JP2019205180A - Hydrogen flame monitoring apparatus and hydrogen handling facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen flame monitoring device capable of highly accurately detecting and visualizing a small hydrogen flame having a small emission intensity even in an environment with a lot of sunlight, and a hydrogen handling facility equipped with such a hydrogen flame monitoring device. A near infrared image capturing means for capturing a near infrared image including a wavelength set within a wavelength range of 1340 to 1500 nm, and a visible light image capturing means for capturing a visible light image are further provided, and the captured near infrared image is further provided. The difference between the infrared image and the visible light image is taken, binarized, and colored to form a flame image, and a calculation device that creates a composite image by superimposing this on a background image consisting of the visible light image, and the obtained composite image A display device for displaying on the screen is provided. According to this configuration, a flame image can be created using near infrared rays in the wavelength range of 1340 to 1500 nm, which is contained in a large amount in hydrogen flames but little in sunlight, so that a small hydrogen flame with a low emission intensity can be used. It is possible to provide a hydrogen flame monitoring device that can be visualized. [Selection diagram]

Description

  The present invention relates to a technique for visualizing a hydrogen flame that is invisible to the naked eye and monitoring the generation of the flame. More specifically, the present invention relates to a hydrogen supply station that supplies hydrogen gas to a fuel cell vehicle, and a chemical factory that produces and uses hydrogen gas. The present invention relates to a hydrogen flame monitoring device suitable for monitoring the occurrence of a flame in a hydrogen handling facility such as, and a hydrogen handling facility provided with such a hydrogen flame monitoring device.

When burning a general substance, carbon in the component burns and emits visible light, so the flame can be seen with the naked eye, but hydrogen gas is almost colorless and transparent even when burned, and with the naked eye It cannot be seen. Therefore, for example, in the event of a fire involving hydrogen gas leakage at a hydrogen handling facility, a technology that can visualize the hydrogen flame and confirm the size and position of the flame is necessary in order to accurately and safely perform the fire fighting operation. It is.
In response to such a request, the applicant of the present invention has made efforts to research and develop a technique for visualizing a colorless and transparent hydrogen flame by image processing. No. 2006-267097), a hydrogen flame visualization device was proposed.

  In the hydrogen flame visualization apparatus described in Patent Document 1, the near-infrared wavelength and the heat ray wavelength were simultaneously detected at the same position in the near-infrared image and the heat ray (far-infrared) image including the wavelength set in the range of 930 to 950 nm. The region is determined to be a hydrogen flame region, an image of the hydrogen flame is created, and the hydrogen flame is visualized by superimposing it on a background image made up of a visible light image.

  Moreover, the hydrogen flame visualization apparatus described in Patent Document 2 captures ultraviolet rays (309 nm) and near infrared rays (950 nm) emitted by a hydrogen flame with a CCD camera, and the difference between these specific wavelength images and adjacent wavelength images. By extracting an image, an image of a hydrogen flame is created, and the hydrogen flame is visualized by superimposing it on an ultraviolet background image or a near infrared background image.

  However, the hydrogen flame visualization measures described in Patent Documents 1 and 2 have the following problems (a) to (c).

(A) The hydrogen flame visualization devices described in Patent Documents 1 and 2 both capture near-infrared images in the wavelength region of 930 to 950 nm, but 930 to be included in the light emitted by the hydrogen flame. The amount of near infrared light at 950 nm is small. Moreover, in order to detect only near-infrared rays in the same wavelength region emitted by a hydrogen flame, it is necessary to remove near-infrared rays having a wavelength close to the same wavelength region contained in sunlight. If an optical bandpass filter that transmits only infrared light is used, the bandwidth (transmission wavelength range) becomes extremely narrow, so not only the near-infrared light amount of sunlight but also the near-infrared light amount of hydrogen flames. Is reduced, making it difficult to detect flames with low emission intensity, such as small hydrogen flames.

(B) In hydrogen handling facilities where hydrogen flame visualization equipment is used, in preparation for hydrogen gas leakage accidents, certain areas where hydrogen supply equipment, hydrogen transport pipes, hydrogen storage tanks, etc. may become ignition sources There is an “explosion-proof area” where it cannot be installed.
Therefore, for example, in the hydrogen flame visualization apparatus described in Patent Documents 1 and 2, a CCD camera for imaging a hydrogen flame using a power source can be an ignition source, so it cannot be installed in an explosion-proof area and is a monitoring target. It had to be installed in a non-explosion-proof area that was quite far from the area. For this reason, it is difficult to detect a small hydrogen flame, and when smoke is generated by a fire or the like, there is a problem that light emitted from the hydrogen flame is blocked by the smoke and cannot be detected.

  Conversely, if you want to install a CCD camera that uses a power supply in an explosion-proof area, you must attach a thick metal hood to the CCD camera, etc. to make it an explosion-proof specification, which increases the size and price of the device. There is a problem that becomes high.

(C) Hydrogen handling facilities where hydrogen flame visualization equipment is used require continuous monitoring means to detect not only hydrogen flames but also abnormalities such as suspicious person intrusions in order to prevent accidents. It is said that.
A general-purpose intruder monitoring device that continuously monitors the intrusion of a suspicious person has a near-infrared image pickup device that picks up a near-infrared image including a wavelength region of approximately 800 to 950 nm and a near-infrared ray in the same wavelength region in many models. A near infrared irradiator for irradiating is provided. The reason is that a near-infrared ray having a relatively short wavelength of 800 to 950 nm can use a general-purpose and inexpensive CCD camera as a near-infrared detector, so that the price of the intruder monitoring device can be kept low. It is.

  Here, since the hydrogen flame visualization apparatus described in Patent Documents 1 and 2 captures a near-infrared image in a wavelength region of 930 to 950 nm, irradiation by the near-infrared irradiator of the general-purpose intruder monitoring apparatus described above. There is a risk of misdetecting light and its reflected light as near-infrared rays from a hydrogen flame. Therefore, there is a problem that such a hydrogen flame visualization device cannot be used together with a general-purpose intruder monitoring device.

JP 2013-36974 A JP 2006-267097 A

Accordingly, an object of the present invention is to provide a hydrogen flame monitoring device that can detect and visualize a small hydrogen flame with low emission intensity with high accuracy even in an environment with a lot of sunlight.
It is another object of the present invention to provide a hydrogen flame monitoring apparatus that can monitor a monitoring target area in an explosion-proof area where hydrogen gas may leak, and that is small in size and excellent in cost.
Furthermore, it is an object to provide a hydrogen flame monitoring device that can be used in combination with such an intruder monitoring device without erroneously detecting near infrared rays emitted from an intruder monitoring device equipped with a general-purpose near infrared irradiator. To do.

It is another object of the present invention to provide a hydrogen handling facility in which a hydrogen flame monitoring device capable of monitoring a monitoring target area is installed in an explosion-proof area where hydrogen gas may leak.
It is another object of the present invention to provide a hydrogen handling facility in which both an intruder monitoring device equipped with a general-purpose near infrared irradiator and a hydrogen flame monitoring device are installed.

The above problems have been solved by the following means.
[1] A hydrogen flame monitoring device for visualizing a hydrogen flame,
A near-infrared image capturing means for capturing a near-infrared image including a wavelength set within a wavelength region of 1340 to 1500 nm;
And an imaging unit comprising visible light image imaging means for imaging a visible light image,
A storage device for recording a near-infrared image and a visible light image of a monitoring target area imaged by the imaging unit;
A difference image between the near-infrared image and the visible light image is extracted, binarized based on a set threshold value to obtain a binary image, further colored to form a flame image, and the flame image is composed of the visible light image. A computing device for creating a composite image superimposed on a background image;
And a hydrogen flame monitoring apparatus comprising: an information processing unit including a display device that displays the composite image on a screen.

[2] The hydrogen flame monitoring device according to [1], wherein the arithmetic unit includes a determination unit that determines presence or absence of a hydrogen flame based on the binary image.

[3] The imaging unit includes a single condensing unit and a spectroscopic unit that distributes light incident on the condensing unit into near infrared rays and visible rays,
In the above [1] or [2], the near infrared light distributed by the spectroscopic means is guided to the near infrared image capturing means, and the visible light is guided to the visible light image capturing means. The hydrogen flame monitoring device described.

[4] The hydrogen flame monitoring as set forth in [3], wherein the condensing means does not have an ignition source, and the condensing means and the spectroscopic means are connected via an optical transmission cable. apparatus.

[5] UV detection means for detecting UV including a wavelength set within a wavelength range of UV emitted by a hydrogen flame,
And a detection unit including a far-infrared detection means for detecting far-infrared light including a wavelength set within a wavelength range of far-infrared emitted by a hydrogen flame,
The arithmetic unit of the information processing unit includes a determination unit that determines that a hydrogen flame has occurred when the detection unit simultaneously detects ultraviolet rays including the set wavelength and far infrared rays including the set wavelength. The hydrogen flame monitoring device according to any one of [1] to [4] above, wherein:

[6] The hydrogen flame monitoring device according to the above [5], wherein the far-infrared detecting means is connected to a condensing means via an optical transmission cable, and the condensing means has no ignition source. .

[7] The hydrogen flame monitoring device according to [5], wherein the far-infrared detecting means includes a far-infrared imaging device that captures a far-infrared image.

[8] In any one of [5] to [7], the light collecting means is connected to the ultraviolet ray detecting means via an optical transmission cable, and the light collecting means does not have an ignition source. The hydrogen flame monitoring device described.

[9] The hydrogen flame monitoring device according to claim 8, wherein the condensing means includes a wavelength converter that converts ultraviolet rays into visible rays.

[10] A hydrogen handling facility with explosion-proof and non-explosion-proof areas,
The hydrogen flame monitoring device according to any one of the above [4], [6], [8] or [9] is installed,
Among the components of these hydrogen flame monitoring devices, each condensing means is arranged in an explosion-proof area,
A hydrogen handling facility characterized in that other components including a spectroscopic means, a far-infrared detecting means or an ultraviolet detecting means connected to the condensing means via an optical transmission cable are arranged in a non-explosion-proof area.

[11] A hydrogen handling facility in which the hydrogen flame monitoring device and the intruder monitoring device according to any one of [1] to [9] are installed,
At least part of the monitoring target area of the hydrogen flame monitoring device and the monitoring target area of the intruder monitoring device overlap,
The intruder monitoring device includes a near infrared ray including a wavelength set within a wavelength region of less than 1340 nm and substantially equal to a wavelength region of a near infrared image captured by the near infrared image capturing unit of the hydrogen flame monitoring device. A hydrogen handling facility comprising a near-infrared irradiator that emits near-infrared rays in a wavelength region that does not overlap.

  The hydrogen flame monitoring device according to the above [1] in the present invention includes an imaging unit including a near-infrared image capturing unit and a visible light image capturing unit, and therefore the near-infrared image capturing unit emits a hydrogen flame. A near-infrared image in the near-infrared wavelength region can be captured, and a visible-light image in the visible-wavelength region without a hydrogen flame emission can be captured by the visible-light image capturing means.

And since the information processing part provided with a memory | storage device, a calculating device, and a display apparatus is comprised, the near-infrared image and visible light image which were imaged by the said imaging part can be recorded with the memory | storage device.
In addition, the difference image between the near infrared image and the visible light image obtained by the arithmetic device is subtracted from the disturbance light components such as illumination light emitted from the various illumination devices reflected in the two images and deleted. Is extracted and binarized with reference to the threshold value set as the difference image, and further colored to form a flame image, and the obtained flame image is superimposed on the background image by the visible light image. A composite image can be created.
Then, by displaying the composite image on the screen by the display device, the hydrogen flame can be visualized, and the size and generation position of the flame can be specified.

  Furthermore, according to the hydrogen flame monitoring apparatus of the present invention, the near-infrared image capturing means captures a near-infrared image including a wavelength set within a wavelength region of 1340 to 1500 nm. , 1430-1500 nm wavelength region is contained in a very large amount, so even a small hydrogen flame with low emission intensity can be clearly imaged and visualized. Moreover, since near infrared rays in the wavelength region of 1340 to 1500 nm are only slightly contained in sunlight, it is possible to prevent a malfunction in which sunlight is erroneously detected as a hydrogen flame.

  Furthermore, the general-purpose intruder monitoring device of the type that detects near infrared rays is provided with a near infrared irradiator that irradiates near infrared rays in a wavelength region of approximately 800 to 950 nm in many models, but the hydrogen flame of the present invention. Since the near-infrared image capturing means of the monitoring device captures a near-infrared image including a wavelength set in the wavelength region of 1340 to 1500 nm, the near-infrared image in the wavelength region of 800 to 950 nm is not imaged. Therefore, according to the hydrogen flame monitoring apparatus of the present invention, there is no possibility of misdetecting the near infrared ray or the reflected light emitted from the near infrared irradiator of the general-purpose intruder monitoring apparatus as the emission of the hydrogen flame. It can be used in combination with the above-mentioned general-purpose intruder monitoring device and is convenient.

Further, the hydrogen flame monitoring apparatus according to the above [2] in the present invention is the hydrogen flame monitoring apparatus according to the above [1], wherein the arithmetic unit includes a discriminating means for discriminating the presence or absence of the hydrogen flame based on the binary image. Have. In the binary image, an area showing a value equal to or greater than the set threshold value is determined as an area where a hydrogen flame exists, and binarized to create an image. It is possible to easily and accurately determine the presence or absence.
Therefore, according to the hydrogen flame monitoring apparatus of the present invention, when a hydrogen flame is detected by the discriminating means, an alarm for generating a hydrogen flame can be issued. Further, it is possible to configure the storage device to store a near-infrared image and a visible light image for a predetermined time before and after the occurrence of the hydrogen flame, using the detection of the hydrogen flame by the determination unit as a trigger.

  Further, the hydrogen flame monitoring apparatus according to the above [3] in the present invention is the hydrogen flame monitoring apparatus according to the above [1] or [2], wherein the imaging unit has a single condensing means and its condensing means. Since the spectroscopic means for dividing the light incident on the light into a near infrared ray and a visible light ray is provided, the angle of view of the near infrared image and the visible light image can be made the same. Therefore, the generation position of the hydrogen flame can be accurately displayed in the composite image in which the flame image is superimposed on the background image.

Furthermore, the hydrogen flame monitoring apparatus according to the above [4] in the present invention is the hydrogen flame monitoring apparatus according to the above [3], in which the condensing means does not have an ignition source, and the condensing means Since the means is connected via the optical transmission cable, it is possible to dispose only the condensing means away from the hydrogen flame monitoring device and to place it where it is not possible to place anything that can be an ignition source.
Therefore, for example, when the hydrogen flame monitoring device of the present invention is installed in a hydrogen handling facility provided with an explosion-proof area and a non-explosion-proof area, the condensing means can be arranged in the explosion-proof area, By arranging the light condensing means in the vicinity of a place where there is a possibility of leakage, the hydrogen flame can be detected with high accuracy.

  In addition, since other components including the light collecting means arranged in the explosion-proof area and the spectroscopic means connected via the optical transmission cable can be arranged in the non-explosion-proof area, the components of the hydrogen flame monitoring device Among them, it is not necessary to use explosion-proof specifications for near-infrared image capturing means and visible image capturing means that can be an ignition source because a power source is used, and the hydrogen flame monitoring device should be small and cost-effective. it can.

  In addition, since the condensing means can be composed of, for example, a lens for condensing light and a member connecting the lens and the optical transmission cable, the condensing means can be formed extremely small in that case. It becomes possible to install in a narrow place.

  In addition, the hydrogen flame monitoring apparatus according to the above [5] in the present invention is set in the wavelength range of ultraviolet rays emitted from the hydrogen flame in the hydrogen flame monitoring apparatus according to any one of the above [1] to [4]. The ultraviolet ray detecting means for detecting the ultraviolet ray including the different wavelength, and the detection unit including the far infrared ray detecting means for detecting the far infrared ray including the wavelength set in the wavelength region of the far infrared ray emitted from the hydrogen flame, the ultraviolet ray is provided. The detection means can detect ultraviolet rays emitted by the hydrogen flame, and the far infrared detection means can detect far infrared rays emitted by the hydrogen flame.

  Then, the arithmetic unit of the information processing unit determines that a hydrogen flame is generated when the detection unit simultaneously detects the ultraviolet ray including the set wavelength and the far infrared ray including the set wavelength. Therefore, the occurrence of a hydrogen flame can be detected with high accuracy. For example, when the ultraviolet ray detection means mistakenly detects the ultraviolet ray contained in the sunlight as the ultraviolet ray emitted from the hydrogen flame, or the far infrared ray detection means causes the temperature rise in the monitored area due to a cause other than the hydrogen flame due to the hydrogen flame. Even if it is mistakenly detected, it is not determined that hydrogen flame is generated unless detection by both detection means is performed at the same time. Therefore, the hydrogen flame monitoring device of the present invention can detect the occurrence of hydrogen flame with high accuracy. It is something that can be done.

  Therefore, according to the hydrogen flame monitoring apparatus of the present invention, it is possible to issue an alarm when the occurrence of a hydrogen flame is detected by the determination means of the arithmetic unit. In addition, with the detection of the occurrence of hydrogen flame by the determination means as a trigger, storage of a near-infrared image and a visible light image for a predetermined time before and after the occurrence of a hydrogen flame in the storage device is started, or a series of images by an arithmetic device You can start the process.

  Furthermore, in order to further improve the detection accuracy of the occurrence of hydrogen flame, the “determination unit” of the arithmetic device may be combined with the “determination unit” that determines the presence or absence of hydrogen flame based on the binary image. For example, when the occurrence of a hydrogen flame is detected by the “determination unit” and the presence of the hydrogen flame is detected by the “determination unit”, it is determined that the hydrogen flame has occurred, As described above, an alarm may be issued, or image storage in the storage device may be started.

The hydrogen flame monitoring apparatus according to [6] in the present invention is the hydrogen flame monitoring apparatus according to [5], wherein the far-infrared detecting means is connected to a condensing means via an optical transmission cable. In addition, since the condensing means does not have an ignition source, it is possible to dispose only the condensing means from the hydrogen flame monitoring device and place the condensing means in a place where an ignition source cannot be arranged.
Therefore, for example, when the hydrogen flame monitoring device of the present invention is installed in a hydrogen handling facility provided with an explosion-proof area and a non-explosion-proof area, the condensing means can be arranged in the explosion-proof area, By arranging the light condensing means in the vicinity of a place where there is a possibility of leakage, the hydrogen flame can be detected with high accuracy.

  Furthermore, other components including the far-infrared detection means connected via the optical transmission cable and the light collecting means arranged in the explosion-proof area can be arranged in the non-explosion-proof area. Of the components, it is not necessary to make the far-infrared detection means, which can be an ignition source because of the use of a power source, an explosion-proof specification, and the hydrogen flame monitoring device can be made small and cost-effective.

  In addition, since the condensing means can be composed of, for example, a lens for condensing light and a member connecting the lens and the optical transmission cable, the condensing means can be formed extremely small in that case. It can be installed in a narrow place.

Moreover, the hydrogen flame monitoring apparatus according to [7] in the present invention is the hydrogen flame monitoring apparatus according to [5], wherein the far infrared detection means includes a far infrared imaging device that captures a far infrared image. Therefore, the far-infrared detection means can be used not only for detecting the occurrence of hydrogen flame but also as a camera for monitoring intruders at night.
Furthermore, based on the far-infrared image acquired by such a far-infrared image pick-up device, the position display and the temperature display of the highest temperature in the monitoring target area are performed, and the temperature rise of the device is detected and the temperature is electrically output. It is also possible to monitor the temperature in the monitored region, such as using as a thermography.
If the far-infrared imaging device is made explosion-proof so that it does not become an ignition source, it can be installed in the vicinity of a location where hydrogen gas may leak, and more hydrogen flames and intruders can be detected. Accuracy can be increased.

Furthermore, the hydrogen flame monitoring apparatus according to the above [8] in the present invention is the hydrogen flame monitoring apparatus according to any one of the above [5] to [7], wherein the light collecting means detects ultraviolet rays via an optical transmission cable. Since the condensing means has no ignition source, it is possible to dispose only the condensing means away from the hydrogen flame monitoring device, and to place the condensing source in a place where it cannot be arranged.
Therefore, the hydrogen flame can be detected with high accuracy by arranging the light condensing means in the vicinity of a place where hydrogen gas may leak. Furthermore, since components other than the light condensing means can be arranged in the non-explosion-proof area, it is not necessary to make them explosion-proof, and the hydrogen flame monitoring device can be made small and cost-effective.

  In addition, since the light condensing means can be composed of, for example, a lens for condensing light and a member connecting the lens and the optical transmission cable, in this case, the light condensing means can be formed to be considerably small. It can be installed in a narrow place.

  Furthermore, the hydrogen flame monitoring device according to the above [9] in the present invention is the hydrogen flame monitoring device according to the above [8], because the condensing means includes a wavelength converter that converts ultraviolet rays into visible rays. Ultraviolet rays from the monitoring target area incident on the light collecting means can be converted into visible light. Therefore, it is possible to use an inexpensive general-purpose product for visible light transmission instead of an expensive special product for ultraviolet transmission as an optical transmission cable for connecting the light collecting means and the ultraviolet detection means. Can be made cost-effective.

In the hydrogen handling facility according to the above [10] in the present invention, the hydrogen flame monitoring device according to any one of the above [4], [6], [8] or [9] is installed. Among the components of the flame monitoring device, each condensing means is disposed in an explosion-proof area, and other condensing means including a spectroscopic means, a far-infrared detecting means or an ultraviolet detecting means connected to the condensing means via an optical transmission cable. Since the components are arranged in the non-explosion-proof area, the hydrogen flame can be detected in the vicinity of a place where there is a risk of leakage of hydrogen gas by the respective light collecting means arranged in the explosion-proof area.
Therefore, in the hydrogen handling facility of the present invention, even a small hydrogen flame can be detected, and the size and position of the hydrogen flame can be accurately identified. Work can be performed accurately and safely.

  In the hydrogen handling facility of the present invention, among the components of the hydrogen flame monitoring device, components that can be ignition sources such as using a power source are arranged in a non-explosion-proof area. Since it is not necessary, it is excellent in cost. In addition, fire due to ignition of leaked hydrogen gas hardly occurs, and it is excellent in safety.

Furthermore, the hydrogen handling facility described in [11] in the present invention is a hydrogen handling facility in which the hydrogen flame monitoring device and the intruder monitoring device described in any of [1] to [9] are installed. And at least part of the monitoring target area of the hydrogen flame monitoring device and the monitoring target area of the intruder monitoring device overlap, and the intruder monitoring device has a wavelength set within a wavelength region of less than 1340 nm. A near-infrared irradiator that irradiates near-infrared rays in a wavelength region that is near-infrared and that does not substantially overlap the wavelength region of the near-infrared image captured by the near-infrared image capturing means of the hydrogen flame monitoring device Therefore, the hydrogen flame monitoring device of the present invention erroneously detects the near infrared ray and the reflected light emitted from the near infrared irradiator of the general-purpose intruder monitoring device as the near infrared ray emitted by the hydrogen flame. No.
Therefore, a general-purpose inexpensive intruder monitoring device can be installed together with the hydrogen flame monitoring device of the present invention, and the same monitoring target area can be monitored simultaneously by both devices, which is convenient and excellent in cost.

  The near-infrared wavelength region detected by the near-infrared imaging device of the hydrogen flame monitoring device and the near-infrared wavelength region irradiated by the near-infrared irradiator of the intruder monitoring device are “substantially not overlapping”. Even if there is a wavelength region that overlaps both, it is a near infrared ray emitted from the near infrared irradiator of the intruder monitoring device, and a near infrared ray emitted from the hydrogen flame by the flame monitoring device. If it is within a range where no erroneous detection is made, the two wavelength regions are understood to be in a state of “substantially not overlapping”.

1 is an overall system diagram of a hydrogen flame monitoring apparatus according to a first embodiment of the present invention. It is a whole system figure of the hydrogen flame monitoring device concerning a 2nd embodiment of the present invention. It is explanatory drawing of the hydrogen handling facility of this invention. It is a graph which shows the emission intensity of a hydrogen flame and sunlight in the near infrared wavelength region.

<< First Embodiment of Hydrogen Flame Monitoring Apparatus >>
First, a first embodiment of the hydrogen flame monitoring device of the present invention will be described.
A hydrogen flame monitoring apparatus 1 illustrated in FIG. 1 includes an imaging unit 2 and an information processing unit 3.
The imaging unit 2 is mainly guided by the light collecting unit 23 that receives light from the monitoring target region, the spectral unit 24 that divides the light received by the light collecting unit 23 into near infrared rays and visible light, and the spectral unit 24. It comprises a near-infrared image capturing means 21 that captures an image by near-infrared light and a visible light image capturing means 22 that captures an image by visible light guided from the spectroscopic means 24.

  The information processing unit 3 uses the storage device 31 that records the near-infrared image and the visible light image transmitted from the imaging unit 2, and the flame image is superimposed on the background image using the near-infrared image and the visible light image. And a display device 33 for displaying the composite image on the screen.

  The basic operation of the information processing unit 3 is to obtain a difference between a near-infrared image of a specific wavelength emitted by a hydrogen flame and a visible light image, and subtract disturbance light components such as illumination light reflected in both images. The erased difference image is extracted, binarized with reference to the threshold value set for the difference image to obtain a binary image, further colored to form a flame image, and the obtained flame image is placed on the background image by the visible light image. The hydrogen flame is visualized by displaying it on the screen as a superimposed composite image.

<Imaging unit>
The condensing unit 23 is connected to the spectroscopic unit 24 via the optical transmission cable 25, and light from the monitoring target region incident on a lens (not shown) provided in the condensing unit 23 is converted into the optical transmission cable. It is configured to pass through 25 and be guided to the spectroscopic means 24.

  The condensing means 23 can be composed of only a lens and a member that connects the lens and the optical transmission cable 25, and therefore does not become a source of ignition, and can be formed extremely small. Therefore, it is difficult to install a CCD camera that uses a normal power source, it can be installed in places where it cannot be ignited, or in extremely narrow places. For example, pressure accumulation in an explosion-proof area of a hydrogen supply station It can also be installed in narrow spaces such as instrument rooms and compressor rooms.

  As the spectroscopic means 24, a known spectroscopic mirror can be used. The spectroscopic mirror is a mirror that reflects visible rays (approximately 400 to 700 nm) and transmits near infrared rays (approximately 800 to 1800 nm), or conversely, is a mirror that transmits visible rays and reflects near infrared rays. May be. Such a spectroscope can be manufactured, for example, by coating a plate glass with dielectric materials having different refractive indexes in a multilayer form.

Further, the spectroscopic unit 24 may be provided with a function as an optical bandpass filter described later in order to reduce the influence of disturbance light. In that case, a spectroscope that transmits or reflects near infrared light including a wavelength arbitrarily set within a wavelength region of 1340 to 1500 nm may be used.
As a specific example of such a spectroscopic means 24, a spectroscope that functions as an optical bandpass filter having a transmission wavelength center of 1350 to 1450 nm and a full width at half maximum of 70 to 90 nm is preferably used. it can.

As the optical transmission cable 25, a cable made of a single optical fiber, an optical fiber bundle cable in which a plurality of optical fibers are bundled, an image fiber cable in which a plurality of optical fibers are bundled and welded, or the like is used. However, it is desirable to use an image fiber cable in order to obtain a clear near-infrared image or a visible light image having a high pixel degree.
The light guided from the condensing means 23 to the spectroscopic means 24 by the optical transmission cable 25 is split into near infrared rays and visible light rays by the spectroscopic means 24, and to the near infrared image capturing means 21 and the visible light image capturing means 22, respectively. Led.

The near-infrared image capturing means 21 is a means for capturing a near-infrared image based on the emission spectrum of H ₂ O generated when hydrogen in the monitoring target region is burned by the near-infrared light guided from the spectroscopic means 24. For example, , A CCD camera equipped with an imaging device capable of capturing a still image or a moving image of a near-infrared image including a wavelength arbitrarily set within a wavelength region of 1340 to 1500 nm.
When such a CCD camera captures a still image, for example, it is preferable if it can automatically capture every few seconds because continuous monitoring is possible. Furthermore, in order to acquire a variety of monitoring images, it is preferable to be able to cover a wide field angle from wide angle to telephoto.

The near-infrared image capturing means 21 may be provided with an optical bandpass filter that transmits only near-infrared light having a specific wavelength in order to reduce the influence of disturbance light. This optical band-pass filter preferably has a full width at half maximum of 10 to 100 nm and further has a full width at half maximum of 50 so that the influence of disturbance light such as illumination light is reduced and the luminance value of the hydrogen flame is not lowered. The thing of -90 nm is more preferable.
In addition, when the function of an optical bandpass filter is given to the spectroscopic means 24, it is not necessary to provide an optical bandpass filter separately.

  As a specific example of the near-infrared image capturing means 21, an InGaAs camera (model number C10633-13) manufactured by Hamamatsu Photonics Co., Ltd. can be suitably used.

  As described above, the near-infrared image capturing means 21 captures a near-infrared image including a wavelength set within the wavelength region of 1340 to 1500 nm. As shown in the graph of FIG. A very large amount of near infrared rays in the wavelength region of 1340 to 1500 nm are contained. For example, the near-infrared emission intensity in the same wavelength region emitted by the hydrogen flame is several times stronger than the emission intensity in the wavelength region of 800 to 950 nm. Therefore, according to the hydrogen flame monitoring apparatus 1, even a small hydrogen flame with low emission intensity can be imaged accurately and visualized clearly.

  Moreover, as shown in the graph of FIG. 4, the near infrared rays of a wavelength range of 1340-1500 nm are contained only a little in sunlight. Therefore, the hydrogen flame monitoring device 1 hardly causes the problem of erroneously detecting sunlight as a hydrogen flame.

FIG. 4 is a graph showing the emission intensity of hydrogen flame and sunlight in the near-infrared wavelength region obtained by the inventors' experiment.
The polygonal line Q1 shows the result of measuring the near-infrared light emission intensity from the nearest position by burning hydrogen gas spouted at a volume of 1 L per minute in the clear sky. The total value with the near-infrared emission intensity contained in sunlight is represented.
A broken line Q2 shows a result of measuring the near-infrared emission intensity under the same conditions as the measurement of Q1, in which hydrogen gas is shut off and no hydrogen flame is present, and the near-infrared light contained in sunlight is shown. Only the emission intensity of is shown.
The horizontal axis (X axis) of the graph indicates the wavelength (unit: nm), and the vertical axis (Y axis) indicates the relative light emission intensity (arbitrary unit).

In order to prevent accidents from occurring, hydrogen handling facilities such as hydrogen supply stations where the hydrogen flame monitoring device 1 is used are continuously monitored to detect not only hydrogen flames but also abnormalities such as suspicious person intrusions. Means are needed.
A general-purpose intruder monitoring device that continuously monitors the intrusion of a suspicious person includes a near-infrared detector that detects a near-infrared ray in a wavelength region of approximately 800 to 950 nm and a near-infrared ray that emits a near-infrared ray in the same wavelength region. An infrared irradiator is provided. If near infrared rays having a relatively short wavelength of 800 to 950 nm are used as described above, a general-purpose inexpensive CCD camera can be used as a near-infrared detector, and the cost of the intruder monitoring device can be kept low. is there.

  Here, since the near-infrared image capturing means 21 of the hydrogen flame monitoring apparatus 1 captures a near-infrared image including a wavelength set within the wavelength region of 1340 to 1500 nm, the near-infrared image capturing unit 21 in the wavelength region of 800 to 950 nm. Infrared is not imaged. Therefore, according to the hydrogen flame monitoring device 1, the near infrared ray or the reflected light emitted from the near infrared irradiator of the general-purpose intruder monitoring device is not erroneously detected as the emission of the hydrogen flame. It can be used together with a general-purpose intruder monitoring device and is convenient.

  Next, the visible light image capturing unit 22 is a unit for capturing a visible light image of the monitoring target region with the visible light guided from the spectroscopic unit 24. For example, the wavelength of the visible light region (400 to 700 nm) is used. It is possible to use a general-purpose CCD camera equipped with an image sensor that can capture a still light image or a moving image of a visible light image including In the case of a CCD camera that captures a still image, for example, any camera that can automatically capture images every few seconds is preferable because continuous monitoring is possible. Furthermore, in order to acquire various monitoring images, it is preferable that a wide angle of view from a wide angle to a telephoto can be covered.

  In addition, a visible light image capturing camera can be used for either color image capturing or monochrome image capturing. However, in general, a color image is easy to see and a hydrogen flame occurrence position can be easily specified. It is desirable to use a camera.

  When the camera for capturing a visible light image is a color CCD camera, a camera equipped with an RGB filter can be used. For the RGB filter, since the red wavelength region is close to the near-infrared wavelength region, it is preferable to use a red signal for extracting the difference image. In addition, since plants scatter strongly near infrared rays, it is preferable to use a green signal that is a wavelength region with high leaf reflectance in an environment with many plants. The image processing software may have a color selection function so that a single color component (red, green, or blue) to be extracted can be selected according to the application.

As a specific example of the visible light image capturing means 22, a color CCD camera (model number WT-250D) manufactured by Watec can be preferably used.
The visible light image capturing means 22 can also be used as an image capturing device for daytime intruder monitoring.

<Information Processing Department>
The information processing unit 3 includes a storage device 31 such as a hard disk, an arithmetic device 32 such as a CPU, and a display device 33 such as a display screen, and can be configured by a personal computer, for example.

A near-infrared image and a visible light image obtained by simultaneously imaging the same monitoring target area by the imaging unit 2 are transmitted to the information processing unit 3 and recorded in the storage device 31.
The storage device 31 normally records a near-infrared image and a visible light image in time series, and erases an old image every time a new image is captured. However, when a hydrogen flame is detected, an image of a predetermined time before and after the flame detection (for example, an image of 24 hours before and after the occurrence of the flame) is stored. By doing so, it is convenient because it is possible to specify a flame occurrence location (hydrogen gas leakage location) after gas shutoff, or to find out the cause of the flame occurrence. To do so, either acquire an image for a predetermined time after the detection of a hydrogen flame and stop updating the image, or move the image for a predetermined time before and after the detection of the flame to another area so that it cannot be overwritten and continue the image update. You can do it.

  The computing device 32 extracts a difference image between the near-infrared image and the visible light image based on the image processing software stored in the storage device 31, binarizes it, colors it into a flame image, and converts it into a visible light image. A series of image processing is performed such that a composite image is created by superimposing the background image on the image.

As a procedure for such image processing, first, a difference image between a near-infrared image and a visible light image is extracted.
Here, the reason for taking the difference between the near-infrared image and the visible light image is that when the near-infrared light emitted by the hydrogen flame is captured, disturbance light such as illumination light exists in the wavelength region, and thus the disturbance light component is visible. This is because the detection is performed using the wavelength of the light beam, and the disturbance light component is subtracted from the near-infrared image to be erased.
When the visible light image is a color image, a single color component image is extracted from the color image and a difference between the near infrared image and the single color component image may be obtained.

Next, the obtained difference image is compared with a set threshold value, a region showing a value equal to or greater than the threshold value is determined as a region where a hydrogen flame exists, and binarization processing is performed to obtain a binary image.
The threshold value used for the binarization process is automatically calculated by a calculation device 32 by creating a density histogram of the difference image and using the known threshold automatic determination method from the histogram.
Note that the threshold setting is not limited to the method in which the arithmetic device automatically calculates and sets as described above. For example, the user manually adjusts the value while viewing the display of the difference image and inputs the value appropriately. A setting method may be used.

  Next, a high-luminance portion of the obtained binary image is compressed, and subsequently expanded to remove fine noise (a portion having a small high-luminance area) and then colored to obtain a flame image. Then, a composite image is created by superimposing the flame image on the background image of the visible light image.

The computing device 32 also has a discriminating means for discriminating the presence or absence of a hydrogen flame based on the binary image. Since the binary image is created by determining an area showing a value equal to or greater than the set threshold as an area where a hydrogen flame exists, the binary image can easily and reliably determine the presence or absence of a hydrogen flame. Can do.
When a hydrogen flame is detected by such a discriminating means, the information processing section 3 issues an alarm for the occurrence of a hydrogen flame, and also stores a near-infrared image and a visible light image for a predetermined time before and after the occurrence of the hydrogen flame in the storage device 31. Operates to save.

  Since the display device 33 is a display screen and can display the composite image in almost real time, it can contribute to a quick and appropriate fire fighting operation.

<< Second Embodiment of Hydrogen Flame Monitoring Apparatus >>
Next, a second embodiment of the hydrogen flame monitoring device of the present invention will be described.
A hydrogen flame monitoring apparatus 10 shown in FIG. 2 is configured by adding a detection unit 4 to the hydrogen flame monitoring apparatus 1 described above, and the detection unit 4 receives ultraviolet rays from the monitoring target region and converts them into visible light. The light means 43 and the ultraviolet-ray detection means 41 which detects the ultraviolet-ray of a specific wavelength from the visible light guide | induced from the condensing means 43 are provided. The detection unit 4 includes a condensing unit 44 that receives far infrared rays from the monitoring target region, and a far infrared ray detecting unit 42 that detects far infrared rays having a specific wavelength guided from the condensing unit 44.
Hereinafter, although the detection part 4 and the information processing part 3 are demonstrated, since the imaging part 2 is the same as the imaging part 2 of the said 1st Embodiment, description is abbreviate | omitted here.

<Detector>
The condensing means 43 includes a lens (not shown) that receives light from the monitoring target area, and a wavelength converter (not shown) that converts ultraviolet light in the wavelength region of 200 to 400 nm into visible light. It is connected to the detection means 41 via the optical transmission cable 45. With this configuration, when ultraviolet rays in the above-described wavelength region emitted by the hydrogen flame enter the lens, the wavelength converter converts the ultraviolet rays into visible light, passes through the optical transmission cable 45, and is guided to the ultraviolet detection means 41.
When visible light transmitted through the optical transmission cable 45 is weak, it may be guided to the ultraviolet ray detection means 41 after being amplified by an amplifier (not shown).

  Here, the reason for converting ultraviolet light to visible light is that a special product for ultraviolet light transmission is required to transmit ultraviolet light as it is with an optical transmission cable, but if it is converted to visible light, it is inexpensive for visible light transmission. This is because a general-purpose product can be used.

The wavelength converter is made of, for example, glass in which a fluorescent material is dispersed, and ultraviolet light incident on the resin excites the fluorescent material to generate visible light, thereby converting the wavelength from ultraviolet light to visible light. It has come to be.
As a specific example of such a visible light converter, functional fluorescent glass “Lumilas” (model number Lumilas-G9) manufactured by Sumita Optical Glass Co., Ltd. can be preferably used.

  Since the condensing means 43 can be composed of only a lens, a wavelength converter, and a member that connects these and the optical transmission cable 45, it does not become an ignition source and can be formed small. Therefore, it is difficult to install a CCD camera using a normal power source, it can be installed in a place where an ignition source cannot be installed, or in an extremely narrow place. For example, it is narrow in an explosion-proof area of a hydrogen supply station. It can also be installed in an accumulator room or a compressor room.

The ultraviolet ray detection means 41 is a sensor that detects ultraviolet rays in a wavelength region of 200 to 400 nm emitted by a hydrogen flame. The ultraviolet rays are converted into visible light in a specific wavelength region by a wavelength converter provided in the light collecting means 43. Therefore, the sensor used for the ultraviolet ray detection means 41 needs to be able to detect visible light in the specific wavelength region.
Therefore, the sensor of the ultraviolet ray detection means 41 can be constituted by a light receiving element having sensitivity only to visible light in a specific wavelength region, and a combination of an optical bandpass filter and a photodiode that transmits only visible light in a specific region. You may comprise by.

Since the ultraviolet rays emitted by the hydrogen flame have emission intensity peaks at wavelengths of 285 nm, 306 nm, and 309 nm, it is preferable to detect the wavelength region including any of the wavelengths indicating these peaks. For example, when it is desired to detect ultraviolet light having a wavelength of 309 nm, the ultraviolet light is converted into visible light by the wavelength converter of the condensing means 43, so that the visible light can be detected by the sensor of the ultraviolet light detecting means 41. That's fine.
As a specific example of the ultraviolet detection means 41, an ultraviolet sensor (model number UV-200) manufactured by Sumita Optical Glass Co., Ltd. can be preferably used.

  Next, the condensing unit 44 includes a lens (not shown) that receives light from the monitoring target region, and is connected to the far-infrared detecting unit 42 via the optical transmission cable 46. With this configuration, the far infrared rays emitted from the hydrogen flame incident on the lens are guided to the far infrared detection means 42 through the optical transmission cable 46.

  The condensing means 44 can be constituted only by a lens and a member that connects the lens and the optical transmission cable 46, and therefore does not become a source of ignition, and can be formed extremely small. Therefore, it can be installed in an explosion-proof area or an extremely narrow place.

The far-infrared detecting means 42 is a means for detecting far-infrared rays caused by the heat of the hydrogen flame, and uses a far-infrared sensor that can detect far-infrared rays including wavelengths set within a wavelength range of approximately 7 to 14 μm. can do.
As a specific example of the far-infrared detector 42 (far-infrared sensor), an infrared flame detector (model number: 1RB-EW) manufactured by NITTAN can be suitably used.

Moreover, when using a far-infrared image pick-up machine as the far-infrared detection means 42, while being able to image the far-infrared image emitted from the hydrogen flame and the peripheral part heated with the hydrogen flame, the far-infrared image resulting from a human body temperature can be imaged. Since it can image, it can be used as an imager for nighttime intruder monitoring.
Furthermore, based on the far-infrared image acquired by such a far-infrared image pick-up device, the position display and the temperature display of the maximum temperature in the monitoring target area are performed, and the temperature rise of the device is detected and the temperature is electrically output. It is also possible to monitor the temperature in the monitored region, such as using as a thermography.

  As a specific example of the far-infrared detecting means 42 (linear infrared imaging device), a long wave infrared camera (model number QUARK2, transmission wavelength 7.5 to 13.5 μm) manufactured by Flare Systems, Inc. can be suitably used.

<Information Processing Department>
The information processing unit 3 of the hydrogen flame monitoring device 10 includes a storage device 31, an arithmetic device 32, and a display device 33, like the information processing unit 3 of the hydrogen flame monitoring device 1 of the first embodiment. It can be configured by a computer.
In the arithmetic device 32, in addition to the components of the arithmetic device 32 of the first embodiment, in the detection unit 4, ultraviolet light having a wavelength emitted by the hydrogen flame and far infrared light having a wavelength caused by the heat of the hydrogen flame are included. Determining means for determining that a hydrogen flame has occurred when detected at the same time is provided.

  Therefore, the hydrogen flame monitoring device 10 can detect the occurrence of a hydrogen flame with high accuracy. The reason is, for example, when the ultraviolet ray detection means 41 erroneously detects the ultraviolet ray contained in the sunlight as the ultraviolet ray emitted from the hydrogen flame, or when the far infrared ray detection means 42 causes a temperature rise in the monitoring target region due to a cause other than the hydrogen flame. This is because it is not determined that a hydrogen flame has occurred unless the detection by both the detection means 41 and 42 is performed at the same time.

The hydrogen flame monitoring device 10 issues an alarm when the determination means of the arithmetic device 32 detects the occurrence of a hydrogen flame.
Further, using the detection of the occurrence of hydrogen flame as a trigger, the storage device 31 starts to store near-infrared images and visible light images for a predetermined time before and after the occurrence of hydrogen flame, and the near-infrared image and visible light by the computing device 32 are started. A series of image processing from extraction of a difference image from an image to creation of a composite image of a hydrogen flame image and a background image is started.

Further, in order to further improve the accuracy of detection of the hydrogen flame, both the “determination unit” of the calculation device 32 and the “determination unit” that determines the presence or absence of the hydrogen flame based on the above binary image can be combined.
For example, when the occurrence of a hydrogen flame is detected by the “determination unit” and the presence of the hydrogen flame is detected by the “determination unit”, it is determined that a hydrogen flame has occurred, and an alarm is issued. It is possible to issue a notification or to start storing a near-infrared image and a visible light image in the storage device 31.

Moreover, since the hydrogen flame monitoring device 10 can be used as an imaging device for monitoring an intruder at night when the far-infrared detecting means 42 is a far-infrared imaging device, it can be used for monitoring an intruder during the daytime. Together with the visible light image capturing means 22 that can be used as an image pickup device, it can be used as a security monitoring device. For example, a hydrogen flame monitoring mode in which no moving object is detected and an intruder detection mode in which a moving object is detected are provided. In the latter case, the moving object is based on a visible light image or far-infrared image, or based on both images. A notification may be issued when (intruder) is detected.
Thus, when the hydrogen flame monitoring device 10 is used as a crime prevention monitoring device, it is not necessary to provide another crime prevention monitoring device for the same monitored area.

≪Hydrogen handling facility≫
Next, the hydrogen handling facility of the present invention will be described.
The hydrogen handling facility 5 shown in FIG. 3 is a hydrogen supply station for filling the fuel cell vehicle C with hydrogen gas, and includes a hydrogen supply device 53 and a hydrogen transport pipe and a hydrogen storage tank (not shown) arranged around the hydrogen supply device 53. A management building 51 and a canopy (roof) 52 that covers these are provided with hydrogen handling equipment.
In the vicinity of the hydrogen supply device 53 of the hydrogen handling facility 5, there is an explosion-proof area E1 that is prohibited from being set up that can be an ignition source, and areas other than the explosion-proof area E1 are non-explosion-proof areas E2. .

A condensing unit 54 of the hydrogen flame monitoring device 10 is installed in the explosion-proof area E1 on the lower surface side of the canopy 52, and the condensing unit 54 is controlled by the optical transmission cable unit 55 in the non-explosion-proof area E2. It is connected to the main body portion of the hydrogen flame monitoring device 10 arranged in the inside.
The light collecting unit 54 is a unit in which the three light collecting means 23, 43 and 44 shown in FIG. 2 are collectively arranged in one small casing, and the optical transmission cable unit 55 is shown in FIG. The three optical transmission cables 25, 45 and 46 shown are bundled together.

  An intruder monitoring device 56 equipped with a near-infrared irradiator is installed in the non-explosion-proof area E2 on the lower surface side of the canopy 52, and a monitoring target area (not shown) by the intruder monitoring device 56 is The region to be monitored S by the light collecting unit 54 of the hydrogen flame monitoring device 10 overlaps in many areas.

  When the hydrogen flame F is generated in the monitoring target area S of the hydrogen handling facility 5, the condensing unit 54 captures the light from the hydrogen flame F, and the optical transmission cable unit 55 and the spectroscopic means 24 of the imaging unit 2 It is transmitted to the ultraviolet detection means 41 and the far infrared detection means 42 of the detection unit 4. Then, the ultraviolet ray detecting means 41 detects ultraviolet rays having a specific wavelength emitted by the hydrogen flame, and the far infrared ray detecting means 42 detects far infrared rays having a specific wavelength caused by the heat of the hydrogen flame. It is determined that a hydrogen flame has occurred, and an alarm is issued. Further, a near-infrared image by a near-infrared ray of a specific wavelength and a visible light image by a visible ray that are spectrally separated by the spectroscopic unit 24 are stored in the storage device 31 for 24 hours before and after the generation of the hydrogen flame F, and the calculation unit 32 Thus, a series of image processing for visualizing the hydrogen flame using the near infrared image and the visible light image is started.

Here, since the condensing unit 54 does not have anything that can be an ignition source, it is arranged in the explosion-proof area E1 so that the entire monitoring target area S can be monitored from a short distance within approximately 5 m. Therefore, even a small hydrogen flame with low emission intensity can be detected, and a clear flame image can be created.
Further, in the hydrogen flame monitoring device 10, the main body part other than the light collecting unit 54 and the optical transmission cable unit 55 is disposed in the management building 51 in the non-explosion-proof area E2, so that the main body part has an explosion-proof specification. Therefore, it is possible to make the hydrogen handling facility 5 excellent in cost.

The intruder monitoring device 56 installed in the non-explosion-proof area E2 of the hydrogen handling facility 5 irradiates a near-infrared image pickup device that picks up a near-infrared image including a wavelength region of approximately 800 to 950 nm and a near-infrared ray in the same wavelength region. It has a near infrared irradiator.
The intruder monitoring device 56 is a widely used intruder monitoring device that monitors and monitors an intruder with a near-infrared image pickup device. At night, the intruder monitoring device 56 is approximately 800 to 950 nm from the near-infrared irradiator. A near infrared ray in the wavelength region is irradiated, and the reflected light is captured by a near infrared image pickup device.

The hydrogen flame monitoring device 10 installed in the hydrogen handling facility 5 includes the near-infrared image capturing means 21, but captures a near-infrared image in the wavelength region of 1340 to 1500 nm. The near-infrared rays of 800 to 950 nm irradiated from the near infrared irradiator are not imaged.
Accordingly, the hydrogen flame monitoring device 10 is a general-purpose intruder monitoring device because there is no possibility of erroneously detecting the irradiation light from the near infrared irradiator of the intruder monitoring device 56 and the reflected light thereof as near infrared light from the hydrogen flame. It can be used together with 56, and is convenient.

  The present invention is suitable for monitoring a fire in a hydrogen handling facility that handles hydrogen in which a flame is not visible during combustion, and is particularly suitable for ensuring the accuracy and safety of a fire fighting operation by visualizing a hydrogen flame. .

1, 10 .. Hydrogen flame monitoring device 2 .. Imaging unit 21 .. Near-infrared image imaging means 22 .. Visible light image imaging means 23 .. Condensing means 24 .. Spectroscopic means 25 .. Optical transmission cable 3. Information processing unit 31 .. Storage device 32 .. Arithmetic device 33 .. Display device 4 .. Detection unit 41 .. Ultraviolet detection means 42 .. Far-infrared detection means 43, 44 .. Condensing means 45, 46. Transmission cable 5 ・ ・ Hydrogen handling facility (hydrogen supply station)
51 .. Management building 52 .. Canopy 53 .. Hydrogen supply device 54 .. Light condensing unit 55 .. Optical transmission cable unit 56 .. Intruder monitoring device C .. Fuel cell vehicle F .. Hydrogen flame E1. Area E2 ・ ・ Non-explosion-proof area S ・ ・ Monitoring area

  The present invention relates to a technique for visualizing a hydrogen flame that is invisible to the naked eye and monitoring the generation of the flame. More specifically, the present invention relates to a hydrogen supply station that supplies hydrogen gas to a fuel cell vehicle, and a chemical factory that produces and uses hydrogen gas. The present invention relates to a hydrogen flame monitoring device suitable for monitoring the occurrence of a flame in a hydrogen handling facility such as, and a hydrogen handling facility provided with such a hydrogen flame monitoring device.

When burning a general substance, carbon in the component burns and emits visible light, so the flame can be seen with the naked eye, but hydrogen gas is almost colorless and transparent even when burned, and with the naked eye It cannot be seen. Therefore, for example, in the event of a fire involving hydrogen gas leakage at a hydrogen handling facility, a technology that can visualize the hydrogen flame and confirm the size and position of the flame is necessary in order to accurately and safely perform the fire fighting operation. It is.
In response to such a request, the applicant of the present invention has worked on research and development of a technique for visualizing a colorless and transparent hydrogen flame by image processing. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2013-36974) and Patent Document 2 (Japanese Patent Application Laid-Open No. 2013-36974) No. 2006-267097), a hydrogen flame visualization device was proposed.

  In the hydrogen flame visualization apparatus described in Patent Document 1, the near-infrared wavelength and the heat ray wavelength were simultaneously detected at the same position in the near-infrared image and the heat ray (far-infrared) image including the wavelength set in the range of 930 to 950 nm. The region is determined to be a hydrogen flame region, an image of the hydrogen flame is created, and the hydrogen flame is visualized by superimposing it on a background image made up of a visible light image.

  Moreover, the hydrogen flame visualization apparatus described in Patent Document 2 captures ultraviolet rays (309 nm) and near infrared rays (950 nm) emitted by a hydrogen flame with a CCD camera, and the difference between these specific wavelength images and adjacent wavelength images. By extracting an image, an image of a hydrogen flame is created, and the hydrogen flame is visualized by superimposing it on an ultraviolet background image or a near infrared background image.

  However, the hydrogen flame visualization measures described in Patent Documents 1 and 2 have the following problems (a) to (c).

(A) The hydrogen flame visualization devices described in Patent Documents 1 and 2 both capture near-infrared images in the wavelength region of 930 to 950 nm, but 930 to be included in the light emitted by the hydrogen flame. The amount of near infrared light at 950 nm is small. Moreover, in order to detect only near-infrared rays in the same wavelength region emitted by a hydrogen flame, it is necessary to remove near-infrared rays having a wavelength close to the same wavelength region contained in sunlight. If an optical bandpass filter that transmits only infrared light is used, the bandwidth (transmission wavelength range) becomes extremely narrow, so not only the near-infrared light amount of sunlight but also the near-infrared light amount of hydrogen flames. Is reduced, making it difficult to detect flames with low emission intensity, such as small hydrogen flames.

(B) In hydrogen handling facilities where hydrogen flame visualization equipment is used, in preparation for hydrogen gas leakage accidents, certain areas where hydrogen supply equipment, hydrogen transport pipes, hydrogen storage tanks, etc. may become ignition sources There is an “explosion-proof area” where it cannot be installed.
Therefore, for example, in the hydrogen flame visualization apparatus described in Patent Documents 1 and 2, a CCD camera for imaging a hydrogen flame using a power source can be an ignition source, so it cannot be installed in an explosion-proof area and is a monitoring target. It had to be installed in a non-explosion-proof area that was quite far from the area. For this reason, it is difficult to detect a small hydrogen flame, and when smoke is generated by a fire or the like, there is a problem that light emitted from the hydrogen flame is blocked by the smoke and cannot be detected.

  Conversely, if you want to install a CCD camera that uses a power supply in an explosion-proof area, you must attach a thick metal hood to the CCD camera, etc. to make it an explosion-proof specification, which increases the size and price of the device. There is a problem that becomes high.

(C) Hydrogen handling facilities where hydrogen flame visualization equipment is used require continuous monitoring means to detect not only hydrogen flames but also abnormalities such as suspicious person intrusions in order to prevent accidents. It is said that.
A general-purpose intruder monitoring device that continuously monitors the intrusion of a suspicious person has a near-infrared image pickup device that picks up a near-infrared image including a wavelength region of approximately 800 to 950 nm and a near-infrared ray in the same wavelength region in many models. A near infrared irradiator for irradiating is provided. The reason is that a near-infrared ray having a relatively short wavelength of 800 to 950 nm can use a general-purpose and inexpensive CCD camera as a near-infrared detector, so that the price of the intruder monitoring device can be kept low. It is.

  Here, since the hydrogen flame visualization apparatus described in Patent Documents 1 and 2 captures a near-infrared image in a wavelength region of 930 to 950 nm, irradiation by the near-infrared irradiator of the general-purpose intruder monitoring apparatus described above. There is a risk of misdetecting light and its reflected light as near-infrared rays from a hydrogen flame. Therefore, there is a problem that such a hydrogen flame visualization device cannot be used together with a general-purpose intruder monitoring device.

JP 2013-36974 A JP 2006-267097 A

Accordingly, an object of the present invention is to provide a hydrogen flame monitoring device that can detect and visualize a small hydrogen flame with low emission intensity with high accuracy even in an environment with a lot of sunlight.
It is another object of the present invention to provide a hydrogen flame monitoring apparatus that can monitor a monitoring target area in an explosion-proof area where hydrogen gas may leak, and that is small in size and excellent in cost.
Furthermore, it is an object to provide a hydrogen flame monitoring device that can be used in combination with such an intruder monitoring device without erroneously detecting near infrared rays emitted from an intruder monitoring device equipped with a general-purpose near infrared irradiator. To do.

It is another object of the present invention to provide a hydrogen handling facility in which a hydrogen flame monitoring device capable of monitoring a monitoring target area is installed in an explosion-proof area where hydrogen gas may leak.
It is another object of the present invention to provide a hydrogen handling facility in which both an intruder monitoring device equipped with a general-purpose near infrared irradiator and a hydrogen flame monitoring device are installed.

The above problems have been solved by the following means.
[1] A hydrogen flame monitoring device for visualizing a hydrogen flame,
A near-infrared image capturing means for capturing a near-infrared image including a wavelength set within a wavelength region of 1340 to 1500 nm;
And an imaging unit comprising visible light image imaging means for imaging a visible light image,
UV detection means for detecting ultraviolet rays including wavelengths set within the wavelength range of ultraviolet rays emitted by hydrogen flames,
And a detection unit comprising a far-infrared detection means for detecting far-infrared light including a wavelength set within a wavelength region of far-infrared emitted by a hydrogen flame,
Storage device for recording the near infrared image and visible light image of the monitored area captured by the imaging unit,
When the detection unit simultaneously detects ultraviolet rays including the set wavelength and far infrared rays including the set wavelength, the determination unit determines that a hydrogen flame is generated, and the near infrared image Extracting the difference image from the visible light image, binarizing it based on the set threshold value to make a binary image, further coloring it to make a flame image, and superimposing the flame image on the background image made up of the visible light image A computing device for creating a composite image,
And a hydrogen flame monitoring apparatus comprising: an information processing unit including a display device that displays the composite image on a screen.

[2] The hydrogen flame monitoring device according to [1], wherein the arithmetic unit includes a determination unit that determines presence or absence of a hydrogen flame based on the binary image.

[3] The hydrogen flame monitoring device according to the above [1] or [2] , wherein the far-infrared detecting means includes a far-infrared imaging device that captures a far-infrared image.

[4] The imaging unit includes a single condensing unit and a spectroscopic unit that divides the light incident on the condensing unit into a near infrared ray and a visible ray,
The above-mentioned [1] to [3], wherein the near infrared rays divided by the spectroscopic means are guided to the near infrared image capturing means, and the visible light is guided to the visible light image capturing means. The hydrogen flame monitoring apparatus in any one .

[5] The hydrogen flame according to [4] , wherein the light collecting means does not have an ignition source, and the light collecting means and the spectroscopic means are connected via an optical transmission cable. Monitoring device.

[6] In the above [5], the light collecting means is connected to the far infrared detecting means and the ultraviolet light detecting means via an optical transmission cable , respectively, and the light collecting means has no ignition source. The hydrogen flame monitoring device described.

[7] A hydrogen handling facility with an explosion-proof area and a non-explosion-proof area,
The hydrogen flame monitoring device according to [6] above is installed,
Among the components of these hydrogen flame monitoring devices, each condensing means is arranged in an explosion-proof area,
A hydrogen handling facility characterized in that other components including a spectroscopic means, a far-infrared detecting means and an ultraviolet detecting means connected to the condensing means via an optical transmission cable are arranged in a non-explosion-proof area.

  The hydrogen flame monitoring device according to the above [1] in the present invention includes an imaging unit including a near-infrared image capturing unit and a visible light image capturing unit, and therefore the near-infrared image capturing unit emits a hydrogen flame. A near-infrared image in the near-infrared wavelength region can be captured, and a visible-light image in the visible-wavelength region without a hydrogen flame emission can be captured by the visible-light image capturing means.

And since the information processing part provided with a memory | storage device, a calculating device, and a display apparatus is comprised, the near-infrared image and visible light image which were imaged by the said imaging part can be recorded with the memory | storage device.
In addition, the difference image between the near infrared image and the visible light image obtained by the arithmetic device is subtracted from the disturbance light components such as illumination light emitted from the various illumination devices reflected in the two images and deleted. Is extracted and binarized with reference to the threshold value set as the difference image, and further colored to form a flame image, and the obtained flame image is superimposed on the background image by the visible light image. A composite image can be created.
Then, by displaying the composite image on the screen by the display device, the hydrogen flame can be visualized, and the size and generation position of the flame can be specified.

  Furthermore, according to the hydrogen flame monitoring apparatus of the present invention, the near-infrared image capturing means captures a near-infrared image including a wavelength set within a wavelength region of 1340 to 1500 nm. , 1430-1500 nm wavelength region is contained in a very large amount, so even a small hydrogen flame with low emission intensity can be clearly imaged and visualized. Moreover, since near infrared rays in the wavelength region of 1340 to 1500 nm are only slightly contained in sunlight, it is possible to prevent a malfunction in which sunlight is erroneously detected as a hydrogen flame.

  Furthermore, the general-purpose intruder monitoring device of the type that detects near infrared rays is provided with a near infrared irradiator that irradiates near infrared rays in a wavelength region of approximately 800 to 950 nm in many models, but the hydrogen flame of the present invention. Since the near-infrared image capturing means of the monitoring device captures a near-infrared image including a wavelength set in the wavelength region of 1340 to 1500 nm, the near-infrared image in the wavelength region of 800 to 950 nm is not imaged. Therefore, according to the hydrogen flame monitoring apparatus of the present invention, there is no possibility of misdetecting the near infrared ray or the reflected light emitted from the near infrared irradiator of the general-purpose intruder monitoring apparatus as the emission of the hydrogen flame. It can be used in combination with the above-mentioned general-purpose intruder monitoring device and is convenient.

The hydrogen flame monitoring apparatus according to [1] in the present invention, far-infrared emitting ultraviolet detector means for detecting the ultraviolet radiation including a wavelength set in the wavelength region of the ultraviolet emitted from the hydrogen flame, and the hydrogen flame In this case, the ultraviolet ray emitted by the hydrogen flame can be detected by the ultraviolet ray detecting means, and the far infrared ray detecting means for detecting the far infrared ray including the wavelength set in the wavelength region of Far infrared rays emitted by a hydrogen flame can be detected by the infrared detection means.

  Then, the arithmetic unit of the information processing unit determines that a hydrogen flame is generated when the detection unit simultaneously detects the ultraviolet ray including the set wavelength and the far infrared ray including the set wavelength. Therefore, the occurrence of a hydrogen flame can be detected with high accuracy. For example, when the ultraviolet ray detection means mistakenly detects the ultraviolet ray contained in the sunlight as the ultraviolet ray emitted from the hydrogen flame, or the far infrared ray detection means causes the temperature rise in the monitored area due to a cause other than the hydrogen flame due to the hydrogen flame. Even if it is mistakenly detected, it is not determined that hydrogen flame is generated unless detection by both detection means is performed at the same time. Therefore, the hydrogen flame monitoring device of the present invention can detect the occurrence of hydrogen flame with high accuracy. It is something that can be done.

  Therefore, according to the hydrogen flame monitoring apparatus of the present invention, it is possible to issue an alarm when the occurrence of a hydrogen flame is detected by the determination means of the arithmetic unit. In addition, with the detection of the occurrence of hydrogen flame by the determination means as a trigger, storage of a near-infrared image and a visible light image for a predetermined time before and after the occurrence of a hydrogen flame in the storage device is started, or a series of images by an arithmetic device You can start the process.

Further, the hydrogen flame monitoring apparatus according to the above [2] in the present invention is the hydrogen flame monitoring apparatus according to the above [1], wherein the arithmetic unit includes a discriminating means for discriminating the presence or absence of the hydrogen flame based on the binary image. Have. In the binary image, an area showing a value equal to or greater than the set threshold value is determined as an area where a hydrogen flame exists, and binarized to create an image. It is possible to easily and accurately determine the presence or absence.
Therefore, according to the hydrogen flame monitoring apparatus of the present invention, the detection accuracy of the occurrence of hydrogen flame can be further enhanced by combining the “discriminating means” of the arithmetic device and the “determining means”. For example, when the occurrence of a hydrogen flame is detected by the “determination unit” and the presence of the hydrogen flame is detected by the “determination unit”, it is determined that the hydrogen flame has occurred, As described above, an alarm may be issued, or image storage in the storage device may be started.

Moreover, the hydrogen flame monitoring apparatus according to [3] in the present invention is the far-infrared image in which the far-infrared detection means captures a far-infrared image in the hydrogen flame monitoring apparatus according to [1] or [2]. Since it consists of an imager, the far-infrared detector can be used not only for detecting the occurrence of hydrogen flame but also as a camera for monitoring intruders at night.
Furthermore, based on the far-infrared image acquired by such a far-infrared image pick-up device, the position display and the temperature display of the highest temperature in the monitoring target area are performed, and the temperature rise of the device is detected and the temperature is electrically output. It is also possible to monitor the temperature in the monitored region, such as using as a thermography.
If the far-infrared imaging device is made explosion-proof so that it does not become an ignition source, it can be installed in the vicinity of a location where hydrogen gas may leak, and more hydrogen flames and intruders can be detected. Accuracy can be increased.

Moreover, the hydrogen flame monitoring apparatus according to the above [4] in the present invention is the hydrogen flame monitoring apparatus according to any one of the above [1] to [3]. Since the spectroscopic unit that divides the light incident on the condensing unit into near infrared rays and visible rays is provided, the angle of view of the near infrared image and the visible ray image can be made the same. Therefore, the generation position of the hydrogen flame can be accurately displayed in the composite image in which the flame image is superimposed on the background image.

Furthermore, the hydrogen flame monitoring apparatus according to the above [5] in the present invention is the hydrogen flame monitoring apparatus according to the above [4] , wherein the condensing means has no ignition source, and the condensing means and the spectroscopic means Since the means is connected via the optical transmission cable, it is possible to dispose only the condensing means away from the hydrogen flame monitoring device and to place it where it is not possible to place anything that can be an ignition source.
Therefore, for example, when the hydrogen flame monitoring device of the present invention is installed in a hydrogen handling facility provided with an explosion-proof area and a non-explosion-proof area, the condensing means can be arranged in the explosion-proof area, By arranging the light condensing means in the vicinity of a place where there is a possibility of leakage, the hydrogen flame can be detected with high accuracy.

  In addition, since other components including the light collecting means arranged in the explosion-proof area and the spectroscopic means connected via the optical transmission cable can be arranged in the non-explosion-proof area, the components of the hydrogen flame monitoring device Among them, it is not necessary to use explosion-proof specifications for near-infrared image capturing means and visible image capturing means that can be an ignition source because a power source is used, and the hydrogen flame monitoring device should be small and cost-effective. it can.

  In addition, since the condensing means can be composed of, for example, a lens for condensing light and a member connecting the lens and the optical transmission cable, the condensing means can be formed extremely small in that case. It becomes possible to install in a narrow place.

Further, the hydrogen flame monitoring apparatus according to the above [6] in the present invention is the hydrogen flame monitoring apparatus according to the above [5], wherein the condensing means is an optical transmission cable for the far infrared detecting means and the ultraviolet detecting means , respectively. Since the condensing means does not have an ignition source, it is possible to dispose only the condensing means away from the hydrogen flame monitoring device and place it where an ignition source cannot be placed. .
Therefore, for example, when the hydrogen flame monitoring device of the present invention is installed in a hydrogen handling facility provided with an explosion-proof area and a non-explosion-proof area, the condensing means can be arranged in the explosion-proof area, By arranging the light condensing means in the vicinity of a place where there is a possibility of leakage, the hydrogen flame can be detected with high accuracy.

In addition, other components including far-infrared detection means and ultraviolet detection means connected via a light transmission cable to the light-collecting means arranged in the explosion-proof area can be arranged in the non-explosion-proof area. Of the components of the flame monitoring device, it is not necessary to make the far-infrared detection means and ultraviolet detection means that can become ignition sources because of the use of a power source, and the hydrogen flame monitoring device is small and cost-effective. can do.

  In addition, since the condensing means can be composed of, for example, a lens for condensing light and a member connecting the lens and the optical transmission cable, the condensing means can be formed extremely small in that case. It can be installed in a narrow place.

Further, in the hydrogen flame monitoring apparatus according to [6], if it has a wavelength converter condensing means of the ultraviolet converts the ultraviolet into visible light, from the monitoring target area incident on the condensing means The ultraviolet rays can be converted into visible rays, which is preferable . In this case, it is possible to use an inexpensive general-purpose product for visible light transmission instead of an expensive special product for ultraviolet transmission as an optical transmission cable for connecting the light collecting means and the ultraviolet detection means. The flame monitoring device can be made cost-effective.

In the hydrogen handling facility described in [7] in the present invention, the hydrogen flame monitoring device described in [6] is installed, and among the components of these hydrogen flame monitoring devices, each condensing means is explosion-proof. Other components are disposed in the non-explosion-proof area, including the spectroscopic means, far-infrared detecting means and ultraviolet detecting means arranged in the area and connected to the light collecting means via an optical transmission cable. Therefore, the hydrogen flame can be detected in the vicinity of a location where there is a risk of leakage of hydrogen gas by each condensing means arranged in the explosion-proof area.
Therefore, in the hydrogen handling facility of the present invention, even a small hydrogen flame can be detected, and the size and position of the hydrogen flame can be accurately identified. Work can be performed accurately and safely.

  In the hydrogen handling facility of the present invention, among the components of the hydrogen flame monitoring device, components that can be ignition sources such as using a power source are arranged in a non-explosion-proof area. Since it is not necessary, it is excellent in cost. In addition, fire due to ignition of leaked hydrogen gas hardly occurs, and it is excellent in safety.

It is a whole system diagram of a hydrogen flame monitoring device concerning a reference form. It is an overall system diagram of a hydrogen flame monitoring apparatus according to implementation embodiments of the present invention. It is explanatory drawing of the hydrogen handling facility of this invention. It is a graph which shows the emission intensity of a hydrogen flame and sunlight in the near infrared wavelength region.

«Reference embodiment of the hydrogen flame monitoring equipment»
First, the reference embodiment of the hydrogen flame monitoring device.
A hydrogen flame monitoring apparatus 1 illustrated in FIG. 1 includes an imaging unit 2 and an information processing unit 3.
The imaging unit 2 is mainly guided by the light collecting unit 23 that receives light from the monitoring target region, the spectral unit 24 that divides the light received by the light collecting unit 23 into near infrared rays and visible light, and the spectral unit 24. It comprises a near-infrared image capturing means 21 that captures an image by near-infrared light and a visible light image capturing means 22 that captures an image by visible light guided from the spectroscopic means 24.

  The information processing unit 3 uses the storage device 31 that records the near-infrared image and the visible light image transmitted from the imaging unit 2, and the flame image is superimposed on the background image using the near-infrared image and the visible light image. And a display device 33 for displaying the composite image on the screen.

  The basic operation of the information processing unit 3 is to obtain a difference between a near-infrared image of a specific wavelength emitted by a hydrogen flame and a visible light image, and subtract disturbance light components such as illumination light reflected in both images. The erased difference image is extracted, binarized with reference to the threshold value set for the difference image to obtain a binary image, further colored to form a flame image, and the obtained flame image is placed on the background image by the visible light image. The hydrogen flame is visualized by displaying it on the screen as a superimposed composite image.

<Imaging unit>
The condensing unit 23 is connected to the spectroscopic unit 24 via the optical transmission cable 25, and light from the monitoring target region incident on a lens (not shown) provided in the condensing unit 23 is converted into the optical transmission cable. It is configured to pass through 25 and be guided to the spectroscopic means 24.

  The condensing means 23 can be composed of only a lens and a member that connects the lens and the optical transmission cable 25, and therefore does not become a source of ignition, and can be formed extremely small. Therefore, it is difficult to install a CCD camera that uses a normal power source, it can be installed in places where it cannot be ignited, or in extremely narrow places. For example, pressure accumulation in an explosion-proof area of a hydrogen supply station It can also be installed in narrow spaces such as instrument rooms and compressor rooms.

  As the spectroscopic means 24, a known spectroscopic mirror can be used. The spectroscopic mirror is a mirror that reflects visible rays (approximately 400 to 700 nm) and transmits near infrared rays (approximately 800 to 1800 nm), or conversely, is a mirror that transmits visible rays and reflects near infrared rays. May be. Such a spectroscope can be manufactured, for example, by coating a plate glass with dielectric materials having different refractive indexes in a multilayer form.

Further, the spectroscopic unit 24 may be provided with a function as an optical bandpass filter described later in order to reduce the influence of disturbance light. In that case, a spectroscope that transmits or reflects near infrared light including a wavelength arbitrarily set within a wavelength region of 1340 to 1500 nm may be used.
As a specific example of such a spectroscopic means 24, a spectroscope that functions as an optical bandpass filter having a transmission wavelength center of 1350 to 1450 nm and a full width at half maximum of 70 to 90 nm is preferably used. it can.

As the optical transmission cable 25, a cable made of a single optical fiber, an optical fiber bundle cable in which a plurality of optical fibers are bundled, an image fiber cable in which a plurality of optical fibers are bundled and welded, or the like is used. However, it is desirable to use an image fiber cable in order to obtain a clear near-infrared image or a visible light image having a high pixel degree.
The light guided from the condensing means 23 to the spectroscopic means 24 by the optical transmission cable 25 is split into near infrared rays and visible light rays by the spectroscopic means 24, and to the near infrared image capturing means 21 and the visible light image capturing means 22, respectively. Led.

The near-infrared image capturing means 21 is a means for capturing a near-infrared image based on the emission spectrum of H ₂ O generated when hydrogen in the monitoring target region is burned by the near-infrared light guided from the spectroscopic means 24. For example, , A CCD camera equipped with an imaging device capable of capturing a still image or a moving image of a near-infrared image including a wavelength arbitrarily set within a wavelength region of 1340 to 1500 nm.
When such a CCD camera captures a still image, for example, it is preferable if it can automatically capture every few seconds because continuous monitoring is possible. Furthermore, in order to acquire a variety of monitoring images, it is preferable to be able to cover a wide field angle from wide angle to telephoto.

The near-infrared image capturing means 21 may be provided with an optical bandpass filter that transmits only near-infrared light having a specific wavelength in order to reduce the influence of disturbance light. This optical band-pass filter preferably has a full width at half maximum of 10 to 100 nm and further has a full width at half maximum of 50 so that the influence of disturbance light such as illumination light is reduced and the luminance value of the hydrogen flame is not lowered. The thing of -90 nm is more preferable.
In addition, when the function of an optical bandpass filter is given to the spectroscopic means 24, it is not necessary to provide an optical bandpass filter separately.

  As a specific example of the near-infrared image capturing means 21, an InGaAs camera (model number C10633-13) manufactured by Hamamatsu Photonics Co., Ltd. can be suitably used.

  As described above, the near-infrared image capturing means 21 captures a near-infrared image including a wavelength set within the wavelength region of 1340 to 1500 nm. As shown in the graph of FIG. A very large amount of near infrared rays in the wavelength region of 1340 to 1500 nm are contained. For example, the near-infrared emission intensity in the same wavelength region emitted by the hydrogen flame is several times stronger than the emission intensity in the wavelength region of 800 to 950 nm. Therefore, according to the hydrogen flame monitoring apparatus 1, even a small hydrogen flame with low emission intensity can be imaged accurately and visualized clearly.

  Moreover, as shown in the graph of FIG. 4, the near infrared rays of a wavelength range of 1340-1500 nm are contained only a little in sunlight. Therefore, the hydrogen flame monitoring device 1 hardly causes the problem of erroneously detecting sunlight as a hydrogen flame.

FIG. 4 is a graph showing the emission intensity of hydrogen flame and sunlight in the near-infrared wavelength region obtained by the inventors' experiment.
The polygonal line Q1 shows the result of measuring the near-infrared light emission intensity from the nearest position by burning hydrogen gas spouted at a volume of 1 L per minute in the clear sky. The total value with the near-infrared emission intensity contained in sunlight is represented.
A broken line Q2 shows a result of measuring the near-infrared emission intensity under the same conditions as the measurement of Q1, in which hydrogen gas is shut off and no hydrogen flame is present, and the near-infrared light contained in sunlight is shown. Only the emission intensity of is shown.
The horizontal axis (X axis) of the graph indicates the wavelength (unit: nm), and the vertical axis (Y axis) indicates the relative light emission intensity (arbitrary unit).

In order to prevent accidents from occurring, hydrogen handling facilities such as hydrogen supply stations where the hydrogen flame monitoring device 1 is used are continuously monitored to detect not only hydrogen flames but also abnormalities such as suspicious person intrusions. Means are needed.
A general-purpose intruder monitoring device that continuously monitors the intrusion of a suspicious person includes a near-infrared detector that detects a near-infrared ray in a wavelength region of approximately 800 to 950 nm and a near-infrared ray that emits a near-infrared ray in the same wavelength region. An infrared irradiator is provided. If near infrared rays having a relatively short wavelength of 800 to 950 nm are used as described above, a general-purpose inexpensive CCD camera can be used as a near-infrared detector, and the cost of the intruder monitoring device can be kept low. is there.

  Here, since the near-infrared image capturing means 21 of the hydrogen flame monitoring apparatus 1 captures a near-infrared image including a wavelength set within the wavelength region of 1340 to 1500 nm, the near-infrared image capturing unit 21 in the wavelength region of 800 to 950 nm. Infrared is not imaged. Therefore, according to the hydrogen flame monitoring device 1, the near infrared ray or the reflected light emitted from the near infrared irradiator of the general-purpose intruder monitoring device is not erroneously detected as the emission of the hydrogen flame. It can be used together with a general-purpose intruder monitoring device and is convenient.

  Next, the visible light image capturing unit 22 is a unit for capturing a visible light image of the monitoring target region with the visible light guided from the spectroscopic unit 24. For example, the wavelength of the visible light region (400 to 700 nm) is used. It is possible to use a general-purpose CCD camera equipped with an image sensor that can capture a still light image or a moving image of a visible light image including In the case of a CCD camera that captures a still image, for example, any camera that can automatically capture images every few seconds is preferable because continuous monitoring is possible. Furthermore, in order to acquire various monitoring images, it is preferable that a wide angle of view from a wide angle to a telephoto can be covered.

  In addition, a visible light image capturing camera can be used for either color image capturing or monochrome image capturing. However, in general, a color image is easy to see and a hydrogen flame occurrence position can be easily specified. It is desirable to use a camera.

  When the camera for capturing a visible light image is a color CCD camera, a camera equipped with an RGB filter can be used. For the RGB filter, since the red wavelength region is close to the near-infrared wavelength region, it is preferable to use a red signal for extracting the difference image. In addition, since plants scatter strongly near infrared rays, it is preferable to use a green signal that is a wavelength region with high leaf reflectance in an environment with many plants. The image processing software may have a color selection function so that a single color component (red, green, or blue) to be extracted can be selected according to the application.

As a specific example of the visible light image capturing means 22, a color CCD camera (model number WT-250D) manufactured by Watec can be preferably used.
The visible light image capturing means 22 can also be used as an image capturing device for daytime intruder monitoring.

<Information Processing Department>
The information processing unit 3 includes a storage device 31 such as a hard disk, an arithmetic device 32 such as a CPU, and a display device 33 such as a display screen, and can be configured by a personal computer, for example.

A near-infrared image and a visible light image obtained by simultaneously imaging the same monitoring target area by the imaging unit 2 are transmitted to the information processing unit 3 and recorded in the storage device 31.
The storage device 31 normally records a near-infrared image and a visible light image in time series, and erases an old image every time a new image is captured. However, when a hydrogen flame is detected, an image of a predetermined time before and after the flame detection (for example, an image of 24 hours before and after the occurrence of the flame) is stored. By doing so, it is convenient because it is possible to specify a flame occurrence location (hydrogen gas leakage location) after gas shutoff, or to find out the cause of the flame occurrence. To do so, either acquire an image for a predetermined time after the detection of a hydrogen flame and stop updating the image, or move the image for a predetermined time before and after the detection of the flame to another area so that it cannot be overwritten and continue the image update. You can do it.

  The computing device 32 extracts a difference image between the near-infrared image and the visible light image based on the image processing software stored in the storage device 31, binarizes it, colors it into a flame image, and converts it into a visible light image. A series of image processing is performed such that a composite image is created by superimposing the background image on the image.

As a procedure for such image processing, first, a difference image between a near-infrared image and a visible light image is extracted.
Here, the reason for taking the difference between the near-infrared image and the visible light image is that when the near-infrared light emitted by the hydrogen flame is captured, disturbance light such as illumination light exists in the wavelength region, and thus the disturbance light component is visible. This is because the detection is performed using the wavelength of the light beam, and the disturbance light component is subtracted from the near-infrared image to be erased.
When the visible light image is a color image, a single color component image is extracted from the color image and a difference between the near infrared image and the single color component image may be obtained.

Next, the obtained difference image is compared with a set threshold value, a region showing a value equal to or greater than the threshold value is determined as a region where a hydrogen flame exists, and binarization processing is performed to obtain a binary image.
The threshold value used for the binarization process is automatically calculated by a calculation device 32 by creating a density histogram of the difference image and using the known threshold automatic determination method from the histogram.
Note that the threshold setting is not limited to the method in which the arithmetic device automatically calculates and sets as described above. For example, the user manually adjusts the value while viewing the display of the difference image and inputs the value appropriately. A setting method may be used.

  Next, a high-luminance portion of the obtained binary image is compressed, and subsequently expanded to remove fine noise (a portion having a small high-luminance area) and then colored to obtain a flame image. Then, a composite image is created by superimposing the flame image on the background image of the visible light image.

The computing device 32 also has a discriminating means for discriminating the presence or absence of a hydrogen flame based on the binary image. Since the binary image is created by determining an area showing a value equal to or greater than the set threshold as an area where a hydrogen flame exists, the binary image can easily and reliably determine the presence or absence of a hydrogen flame. Can do.
When a hydrogen flame is detected by such a discriminating means, the information processing section 3 issues an alarm for the occurrence of a hydrogen flame, and also stores a near-infrared image and a visible light image for a predetermined time before and after the occurrence of the hydrogen flame in the storage device 31. Operates to save.

  Since the display device 33 is a display screen and can display the composite image in almost real time, it can contribute to a quick and appropriate fire fighting operation.

«Implementation form of hydrogen flame monitoring equipment»
Next, the implementation form of the hydrogen flame monitoring device of the present invention.
A hydrogen flame monitoring apparatus 10 shown in FIG. 2 is configured by adding a detection unit 4 to the hydrogen flame monitoring apparatus 1 described above, and the detection unit 4 receives ultraviolet rays from the monitoring target region and converts them into visible light. The light means 43 and the ultraviolet-ray detection means 41 which detects the ultraviolet-ray of a specific wavelength from the visible light guide | induced from the condensing means 43 are provided. The detection unit 4 includes a condensing unit 44 that receives far infrared rays from the monitoring target region, and a far infrared ray detecting unit 42 that detects far infrared rays having a specific wavelength guided from the condensing unit 44.
Hereinafter, although the detection part 4 and the information processing part 3 are demonstrated, since the imaging part 2 is the same as the imaging part 2 of the said reference form, description is abbreviate | omitted here.

<Detector>
The condensing means 43 includes a lens (not shown) that receives light from the monitoring target area, and a wavelength converter (not shown) that converts ultraviolet light in the wavelength region of 200 to 400 nm into visible light. It is connected to the detection means 41 via the optical transmission cable 45. With this configuration, when ultraviolet rays in the above-described wavelength region emitted by the hydrogen flame enter the lens, the wavelength converter converts the ultraviolet rays into visible light, passes through the optical transmission cable 45, and is guided to the ultraviolet detection means 41.
When visible light transmitted through the optical transmission cable 45 is weak, it may be guided to the ultraviolet ray detection means 41 after being amplified by an amplifier (not shown).

  Here, the reason for converting ultraviolet light to visible light is that a special product for ultraviolet light transmission is required to transmit ultraviolet light as it is with an optical transmission cable, but if it is converted to visible light, it is inexpensive for visible light transmission. This is because a general-purpose product can be used.

The wavelength converter is made of, for example, glass in which a fluorescent material is dispersed, and ultraviolet light incident on the resin excites the fluorescent material to generate visible light, thereby converting the wavelength from ultraviolet light to visible light. It has come to be.
As a specific example of such a visible light converter, functional fluorescent glass “Lumilas” (model number Lumilas-G9) manufactured by Sumita Optical Glass Co., Ltd. can be preferably used.

  Since the condensing means 43 can be composed of only a lens, a wavelength converter, and a member that connects these and the optical transmission cable 45, it does not become an ignition source and can be formed small. Therefore, it is difficult to install a CCD camera using a normal power source, it can be installed in a place where an ignition source cannot be installed, or in an extremely narrow place. For example, it is narrow in an explosion-proof area of a hydrogen supply station. It can also be installed in an accumulator room or a compressor room.

The ultraviolet ray detection means 41 is a sensor that detects ultraviolet rays in a wavelength region of 200 to 400 nm emitted by a hydrogen flame. The ultraviolet rays are converted into visible light in a specific wavelength region by a wavelength converter provided in the light collecting means 43. Therefore, the sensor used for the ultraviolet ray detection means 41 needs to be able to detect visible light in the specific wavelength region.
Therefore, the sensor of the ultraviolet ray detection means 41 can be constituted by a light receiving element having sensitivity only to visible light in a specific wavelength region, and a combination of an optical bandpass filter and a photodiode that transmits only visible light in a specific region. You may comprise by.

Since the ultraviolet rays emitted by the hydrogen flame have emission intensity peaks at wavelengths of 285 nm, 306 nm, and 309 nm, it is preferable to detect the wavelength region including any of the wavelengths indicating these peaks. For example, when it is desired to detect ultraviolet light having a wavelength of 309 nm, the ultraviolet light is converted into visible light by the wavelength converter of the condensing means 43, so that the visible light can be detected by the sensor of the ultraviolet light detecting means 41. That's fine.
As a specific example of the ultraviolet detection means 41, an ultraviolet sensor (model number UV-200) manufactured by Sumita Optical Glass Co., Ltd. can be preferably used.

  Next, the condensing unit 44 includes a lens (not shown) that receives light from the monitoring target region, and is connected to the far-infrared detecting unit 42 via the optical transmission cable 46. With this configuration, the far infrared rays emitted from the hydrogen flame incident on the lens are guided to the far infrared detection means 42 through the optical transmission cable 46.

  The condensing means 44 can be constituted only by a lens and a member that connects the lens and the optical transmission cable 46, and therefore does not become a source of ignition, and can be formed extremely small. Therefore, it can be installed in an explosion-proof area or an extremely narrow place.

The far-infrared detecting means 42 is a means for detecting far-infrared rays caused by the heat of the hydrogen flame, and uses a far-infrared sensor that can detect far-infrared rays including wavelengths set within a wavelength range of approximately 7 to 14 μm. can do.
As a specific example of the far-infrared detector 42 (far-infrared sensor), an infrared flame detector (model number: 1RB-EW) manufactured by NITTAN can be suitably used.

Moreover, when using a far-infrared image pick-up machine as the far-infrared detection means 42, while being able to image the far-infrared image emitted from the hydrogen flame and the peripheral part heated with the hydrogen flame, the far-infrared image resulting from a human body temperature can be imaged. Since it can image, it can be used as an imager for nighttime intruder monitoring.
Furthermore, based on the far-infrared image acquired by such a far-infrared image pick-up device, the position display and the temperature display of the maximum temperature in the monitoring target area are performed, and the temperature rise of the device is detected and the temperature is electrically output. It is also possible to monitor the temperature in the monitored region, such as using as a thermography.

  As a specific example of the far-infrared detecting means 42 (linear infrared imaging device), a long wave infrared camera (model number QUARK2, transmission wavelength 7.5 to 13.5 μm) manufactured by Flare Systems, Inc. can be suitably used.

<Information Processing Department>
The information processing unit 3 of the hydrogen flame monitoring device 10 includes a storage device 31, an arithmetic device 32, and a display device 33, like the information processing unit 3 of the hydrogen flame monitoring device 1 of the first embodiment. It can be configured by a computer.
In the arithmetic device 32, in addition to the constituent elements of the arithmetic device 32 of the reference embodiment, the detection unit 4 simultaneously detects ultraviolet rays having a wavelength generated by the hydrogen flame and far infrared rays having a wavelength caused by the heat of the hydrogen flame. In this case, determination means for determining that a hydrogen flame has occurred is provided.

  Therefore, the hydrogen flame monitoring device 10 can detect the occurrence of a hydrogen flame with high accuracy. The reason is, for example, when the ultraviolet ray detection means 41 erroneously detects the ultraviolet ray contained in the sunlight as the ultraviolet ray emitted from the hydrogen flame, or when the far infrared ray detection means 42 causes a temperature rise in the monitoring target region due to a cause other than the hydrogen flame. This is because it is not determined that a hydrogen flame has occurred unless the detection by both the detection means 41 and 42 is performed at the same time.

The hydrogen flame monitoring device 10 issues an alarm when the determination means of the arithmetic device 32 detects the occurrence of a hydrogen flame.
Further, using the detection of the occurrence of hydrogen flame as a trigger, the storage device 31 starts to store near-infrared images and visible light images for a predetermined time before and after the occurrence of hydrogen flame, and the near-infrared image and visible light by the computing device 32 are started. A series of image processing from extraction of a difference image from an image to creation of a composite image of a hydrogen flame image and a background image is started.

Further, in order to further improve the accuracy of detection of the hydrogen flame, both the “determination unit” of the calculation device 32 and the “determination unit” that determines the presence or absence of the hydrogen flame based on the above binary image can be combined.
For example, when the occurrence of a hydrogen flame is detected by the “determination unit” and the presence of the hydrogen flame is detected by the “determination unit”, it is determined that a hydrogen flame has occurred, and an alarm is issued. It is possible to issue a notification or to start storing a near-infrared image and a visible light image in the storage device 31.

Moreover, since the hydrogen flame monitoring device 10 can be used as an imaging device for monitoring an intruder at night when the far-infrared detecting means 42 is a far-infrared imaging device, it can be used for monitoring an intruder during the daytime. Together with the visible light image capturing means 22 that can be used as an image pickup device, it can be used as a security monitoring device. For example, a hydrogen flame monitoring mode in which no moving object is detected and an intruder detection mode in which a moving object is detected are provided. In the latter case, the moving object is based on a visible light image or far-infrared image, or based on both images. A notification may be issued when (intruder) is detected.
Thus, when the hydrogen flame monitoring device 10 is used as a crime prevention monitoring device, it is not necessary to provide another crime prevention monitoring device for the same monitored area.

≪Hydrogen handling facility≫
Next, the hydrogen handling facility of the present invention will be described.
The hydrogen handling facility 5 shown in FIG. 3 is a hydrogen supply station for filling the fuel cell vehicle C with hydrogen gas, and includes a hydrogen supply device 53 and a hydrogen transport pipe and a hydrogen storage tank (not shown) arranged around the hydrogen supply device 53. A management building 51 and a canopy (roof) 52 that covers these are provided with hydrogen handling equipment.
In the vicinity of the hydrogen supply device 53 of the hydrogen handling facility 5, there is an explosion-proof area E1 that is prohibited from being set up that can be an ignition source, and areas other than the explosion-proof area E1 are non-explosion-proof areas E2. .

A condensing unit 54 of the hydrogen flame monitoring device 10 is installed in the explosion-proof area E1 on the lower surface side of the canopy 52, and the condensing unit 54 is controlled by the optical transmission cable unit 55 in the non-explosion-proof area E2. It is connected to the main body portion of the hydrogen flame monitoring device 10 arranged in the inside.
The light collecting unit 54 is a unit in which the three light collecting means 23, 43 and 44 shown in FIG. 2 are collectively arranged in one small casing, and the optical transmission cable unit 55 is shown in FIG. The three optical transmission cables 25, 45 and 46 shown are bundled together.

  An intruder monitoring device 56 equipped with a near-infrared irradiator is installed in the non-explosion-proof area E2 on the lower surface side of the canopy 52, and a monitoring target area (not shown) by the intruder monitoring device 56 is The region to be monitored S by the light collecting unit 54 of the hydrogen flame monitoring device 10 overlaps in many areas.

  When the hydrogen flame F is generated in the monitoring target area S of the hydrogen handling facility 5, the condensing unit 54 captures the light from the hydrogen flame F, and the optical transmission cable unit 55 and the spectroscopic means 24 of the imaging unit 2 It is transmitted to the ultraviolet detection means 41 and the far infrared detection means 42 of the detection unit 4. Then, the ultraviolet ray detecting means 41 detects ultraviolet rays having a specific wavelength emitted by the hydrogen flame, and the far infrared ray detecting means 42 detects far infrared rays having a specific wavelength caused by the heat of the hydrogen flame. It is determined that a hydrogen flame has occurred, and an alarm is issued. Further, a near-infrared image by a near-infrared ray of a specific wavelength and a visible light image by a visible ray that are spectrally separated by the spectroscopic unit 24 are stored in the storage device 31 for 24 hours before and after the generation of the hydrogen flame F, and the calculation unit 32 Thus, a series of image processing for visualizing the hydrogen flame using the near infrared image and the visible light image is started.

Here, since the condensing unit 54 does not have anything that can be an ignition source, it is arranged in the explosion-proof area E1 so that the entire monitoring target area S can be monitored from a short distance within approximately 5 m. Therefore, even a small hydrogen flame with low emission intensity can be detected, and a clear flame image can be created.
Further, in the hydrogen flame monitoring device 10, the main body part other than the light collecting unit 54 and the optical transmission cable unit 55 is disposed in the management building 51 in the non-explosion-proof area E2, so that the main body part has an explosion-proof specification. Therefore, it is possible to make the hydrogen handling facility 5 excellent in cost.

The intruder monitoring device 56 installed in the non-explosion-proof area E2 of the hydrogen handling facility 5 irradiates a near-infrared image pickup device that picks up a near-infrared image including a wavelength region of approximately 800 to 950 nm and a near-infrared ray in the same wavelength region. It has a near infrared irradiator.
The intruder monitoring device 56 is a widely used intruder monitoring device that monitors and monitors an intruder with a near-infrared image pickup device. At night, the intruder monitoring device 56 is approximately 800 to 950 nm from the near-infrared irradiator. A near infrared ray in the wavelength region is irradiated, and the reflected light is captured by a near infrared image pickup device.

The hydrogen flame monitoring device 10 installed in the hydrogen handling facility 5 includes the near-infrared image capturing means 21, but captures a near-infrared image in the wavelength region of 1340 to 1500 nm. The near-infrared rays of 800 to 950 nm irradiated from the near infrared irradiator are not imaged.
Accordingly, the hydrogen flame monitoring device 10 is a general-purpose intruder monitoring device because there is no possibility of erroneously detecting the irradiation light from the near infrared irradiator of the intruder monitoring device 56 and the reflected light thereof as near infrared light from the hydrogen flame. It can be used together with 56, and is convenient.

  The present invention is suitable for monitoring a fire in a hydrogen handling facility that handles hydrogen in which a flame is not visible during combustion, and is particularly suitable for ensuring the accuracy and safety of a fire fighting operation by visualizing a hydrogen flame. .

1, 10 .. Hydrogen flame monitoring device 2 .. Imaging unit 21 .. Near-infrared image imaging means 22 .. Visible light image imaging means 23 .. Condensing means 24 .. Spectroscopic means 25 .. Optical transmission cable 3. Information processing unit 31 .. Storage device 32 .. Arithmetic device 33 .. Display device 4 .. Detection unit 41 .. Ultraviolet detection means 42 .. Far-infrared detection means 43, 44 .. Condensing means 45, 46. Transmission cable 5 ・ ・ Hydrogen handling facility (hydrogen supply station)
51 .. Management building 52 .. Canopy 53 .. Hydrogen supply device 54 .. Light condensing unit 55 .. Optical transmission cable unit 56 .. Intruder monitoring device C .. Fuel cell vehicle F .. Hydrogen flame E1. Area E2 ・ ・ Non-explosion-proof area S ・ ・ Monitoring area

Claims (11)

A hydrogen flame monitoring device for visualizing a hydrogen flame,
A near-infrared image capturing means for capturing a near-infrared image including a wavelength set within a wavelength region of 1340 to 1500 nm;
And an imaging unit comprising visible light image imaging means for imaging a visible light image,
A storage device for recording a near-infrared image and a visible light image of a monitoring target area imaged by the imaging unit;
A difference image between the near-infrared image and the visible light image is extracted, binarized based on a set threshold value to obtain a binary image, further colored to form a flame image, and the flame image is composed of the visible light image. A computing device for creating a composite image superimposed on a background image;
And a hydrogen flame monitoring apparatus comprising: an information processing unit including a display device that displays the composite image on a screen.   The hydrogen flame monitoring apparatus according to claim 1, wherein the arithmetic unit has a discriminating unit that discriminates the presence or absence of a hydrogen flame based on the binary image. The imaging unit includes a single condensing unit and a spectroscopic unit that divides light incident on the condensing unit into a near infrared ray and a visible ray,
The near infrared ray divided by the spectroscopic means is guided to the near infrared image capturing means, and the visible light is guided to the visible light image capturing means. Hydrogen flame monitoring device.   4. The hydrogen flame monitoring apparatus according to claim 3, wherein the condensing means does not have an ignition source, and the condensing means and the spectroscopic means are connected via an optical transmission cable. UV detection means for detecting ultraviolet rays including wavelengths set within the wavelength range of ultraviolet rays emitted by hydrogen flames,
And a detection unit including a far-infrared detection means for detecting far-infrared light including a wavelength set within a wavelength range of far-infrared emitted by a hydrogen flame,
The arithmetic unit of the information processing unit includes a determination unit that determines that a hydrogen flame has occurred when the detection unit simultaneously detects ultraviolet rays including the set wavelength and far infrared rays including the set wavelength. The hydrogen flame monitoring device according to any one of claims 1 to 4, wherein the hydrogen flame monitoring device is provided.   6. The hydrogen flame monitoring apparatus according to claim 5, wherein the far-infrared detecting means is connected to a condensing means via an optical transmission cable, and the condensing means has no ignition source.   6. The hydrogen flame monitoring apparatus according to claim 5, wherein the far-infrared detector comprises a far-infrared image pickup device that picks up a far-infrared image.   The hydrogen flame according to any one of claims 5 to 7, wherein a condensing means is connected to the ultraviolet ray detecting means via an optical transmission cable, and the condensing means does not have an ignition source. Monitoring device.   9. The hydrogen flame monitoring apparatus according to claim 8, wherein the condensing means includes a wavelength converter that converts ultraviolet light into visible light. A hydrogen handling facility with explosion-proof and non-explosion-proof areas,
The hydrogen flame monitoring device according to any one of claims 4, 6, 8, or 9 is installed,
Among the components of these hydrogen flame monitoring devices, each condensing means is arranged in an explosion-proof area,
A hydrogen handling facility characterized in that other components including a spectroscopic means, a far-infrared detecting means or an ultraviolet detecting means connected to the condensing means via an optical transmission cable are arranged in a non-explosion-proof area. A hydrogen handling facility in which the hydrogen flame monitoring device and the intruder monitoring device according to any one of claims 1 to 9 are installed,
At least part of the monitoring target area of the hydrogen flame monitoring device and the monitoring target area of the intruder monitoring device overlap,
The intruder monitoring device includes a near infrared ray including a wavelength set within a wavelength region of less than 1340 nm and substantially equal to a wavelength region of a near infrared image captured by the near infrared image capturing unit of the hydrogen flame monitoring device. A hydrogen handling facility comprising a near-infrared irradiator that emits near-infrared rays in a wavelength region that does not overlap.

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