JP2007218878A - Gas detector tube photographing device, gas detector tube measuring device, gas concentration measuring system and method thereof - Google Patents

Abstract

An object of the present invention is to provide a gas detector tube imaging device capable of obtaining a stable image when a plurality of gas detector tubes are simultaneously imaged using a camera.
A support member 106 that arranges a plurality of gas detection tubes 100 on the same plane, a surface emission type illumination unit 103 that illuminates the plurality of gas detection tubes 100 supported by the support member 106, and an illumination unit 103. And a housing 101 that shields the space between the illumination light from the illumination means 103 and the camera 110 that captures the transmitted light that passes through the plurality of gas detection tubes 100 from outside light.
[Selection] Figure 2

Description

  The present invention relates to a gas detector tube imaging device used for gas concentration measurement using a gas detector tube, a gas detector tube measuring device using the gas detector tube imaging device, a gas concentration measuring system using the gas detector tube measuring device, and It relates to that method.

  When measuring the gas concentration, measurement using a gas detector tube is performed. The gas detector tube is filled with a reagent (detector) that causes a color change when exposed to a specific gas, and detects the gas concentration by reading the length of the discolored layer. The gas detector tube is easy to handle and can detect the concentration of the target gas component simply and in a short time regardless of the level of skill of the operator.

  Conventionally, the color change length of the gas detection tube has been read visually, but the present inventors previously proposed a method for obtaining the color change layer by reading it with an optical scanner (Patent Document 1, Non-Patent Documents 1 to 3). . Data reproducibility is improved by automatic reading, and the amount of color change can be measured with good reproducibility even when the color change boundary is blurred. Furthermore, even a slight color change can be detected, and a slight color change change can be measured. Further, a lot of noise is mixed in the detector tube image, which can also be reduced by signal processing. In addition to these, if an accumulation effect by continuous suction is added, a sensitivity higher by one digit or more than that of the visual reading device can be achieved.

  However, in order to read a plurality of detection tubes by an optical scanner using a line sensor such as a one-dimensional CCD, a mechanical mechanism that scans by moving the sensor or subject in a direction perpendicular to the line direction of the line sensor is used. It was necessary and there was a limit to miniaturization of the device.

  A reader that reads the discoloration length of a gas detector tube optically without a mechanical scan by arranging a line sensor parallel to the axial direction of the detector tube is also conceivable, but only one type of detector tube can be measured at the same time. However, in order to simultaneously measure the concentrations of a plurality of gases using a plurality of detection tubes, a plurality of line sensors are required, and a plurality of control circuits for the line sensors are also required, resulting in a high cost.

Furthermore, Patent Document 2 discloses a measuring apparatus that photographs a plurality of detection tubes at once using a camera. However, in order to simultaneously photograph a plurality of detector tubes with a camera using a two-dimensional imaging sensor, it is necessary to photograph the detector tube and the camera from a distant position rather than closely contacting each other. For example, a digital camera having a camera lens with a focal length of 4.7 mm and a 1 / 2-type CCD sensor (diagonal length of sensor chip is 8 mm, aspect ratio is 3: 4, long side is 6.4 mm), and has a length of 100 mm. The distance L between the subject and the camera lens for photographing the detection agent layer of the detection tube so as to be within the long side of the camera can be calculated by the following equation.
L = 4.7 mm × (100 / 6.4) = 73 mm
That is, it can be seen that the camera lens needs to be separated by 73 mm or more from the detection tube that is the subject.

  When the subject is illuminated from a distant location and the reflected light is photographed with a camera, the positional relationship between the illumination light source, the subject, and the camera is not uniform, and depending on the location of the subject, it may be positive from the glass surface of the gas detector tube. Reflected light may enter the camera and it is difficult to obtain a stable image.

Japanese Patent Laying-Open No. 2005-62026 (paragraph 0030 to paragraph 0031, FIG. 3) JP 2002-131305 A (paragraph 0005, FIG. 1) Tanaka, Yoshioka, Nakamoto, Moriizumi, “Examination of gas interference characteristics and sensitivity improvement by optical malodor sensing system using gas detector tube”, IEEJ Transactions, 125E (2005), pp64-69 Tanaka, Yoshioka, Nakamoto, Moriizumi, “Studies on Odor Sensing Using Gas Detector Tubes”, IEEJ Transactions, 124E (2004), pp321-326 Tanaka, Nakamoto, Moriizumi, “Study on portable malodor sensing network using gas detector tube and 1D CCD image sensor”, Institute of Electrical Engineers of Chemical Sensors, CHS-05-13 (2005)

  Therefore, in the present invention, when photographing a plurality of gas detector tubes at the same time using a camera, a gas detector tube imaging device capable of obtaining a stable image, a gas detector tube measuring device using the gas detector tube imaging device, and An object of the present invention is to provide a gas concentration measuring device and method using the gas detector tube measuring device.

  The present invention was devised to achieve the above-described object, and the gas detector tube photographing apparatus according to claim 1 shoots the transmitted light transmitted through the gas detector tube with a camera having a two-dimensional image sensor. This is a gas detector tube photographing apparatus for providing a structure including a support member, illumination means, and a housing.

  According to the gas detector tube photographing apparatus having such a configuration, the plurality of gas detector tubes are supported by the support member in a state of being arranged on substantially the same plane. The plurality of gas detection tubes arranged in the same plane by the support member are uniformly illuminated by the surface emitting illumination means. And the transmitted light which permeate | transmitted the several gas detection tube passes the inside of the housing | casing which shields external light, and injects into the camera provided with the two-dimensional image sensor.

  In addition to the configuration of the gas detector tube imaging device according to claim 1, the gas detector tube imaging device according to claim 2 is configured to transmit the plurality of gas detector tubes between the gas detector tube and the camera. A light shielding member that selectively transmits light is provided.

  According to the gas detector tube photographing apparatus having such a configuration, only the transmitted light that has passed through the plurality of gas detector tubes out of the illumination light emitted from the illumination means selectively passes through the slit provided in the light shielding member, Incident on the camera.

  The gas detection tube measuring apparatus according to claim 3, wherein the gas detection tube according to claim 1 or 2 is used for photographing the transmitted light that passes through the plurality of gas detection tubes with a camera including a two-dimensional imaging device. A tube photographing device, a camera, a pump, and a controller are provided.

According to this configuration, the gas detection tube measuring apparatus uniformly illuminates the plurality of gas detection tubes arranged in substantially the same plane by the gas detection tube imaging device, and transmits the transmitted light that has passed through the plurality of gas detection tubes. Can be incident. The controller drives (ON) the pump to allow the gas to be detected to pass through the plurality of gas detection tubes for an appropriate period of time, and stops the pump (OFF) to stop the gas flow to the gas detection tubes. be able to. Further, the controller can control lighting (ON) and extinguishing (OFF) of the illumination means at an appropriate timing. Further, the controller can cause the camera to take an image at an appropriate timing.
The gas detection tube measuring apparatus ventilates the gas (atmosphere) to the gas detection tube by performing ON / OFF control of the pump at an appropriate timing using a controller, and becomes a detection agent and a detection target filled in the gas detection tube. The detection agent is discolored by reacting gas components. The gas detection tube measuring apparatus controls the illumination means at an appropriate timing by a controller and controls the camera to control a plurality of gas detection tubes arranged substantially on a plane by the gas detection tube imaging device. Take a transmitted light image.

  A gas concentration measurement system according to claim 4 includes a gas detector tube measuring device according to claim 3, a receiving means for receiving image data, and gas data by analyzing the image data. And a data management means having an image analysis means for calculating the density.

  According to the gas concentration measurement system having such a configuration, the gas detection tube measurement device controls the pump, the illumination unit, and the camera at appropriate timings to capture and transmit the transmitted light images of the plurality of gas detection tubes that are ventilated and discolored. The photographed image data is transmitted to the data management means using the means. The image data can be transmitted using, for example, a communication means such as a mobile phone. The image data is attached to an e-mail and transmitted to a predetermined mail address that can be received by the data management means. On the other hand, the data management means receives the e-mail attached with the image data transmitted from the gas detector tube measuring device using the receiving means. The data management means acquires the image data attached to the e-mail, and calculates the gas concentration from the image data using the image analysis means. A computer can be used as the data management means, and can function as a reception means and an image analysis means by appropriately executing a program. When the transmission form from the transmission unit is an email, the computer functions as a reception unit, connects to the email address of the transmitted email, receives the email, and acquires image data attached to the email . Next, the computer functions as an image analysis unit, analyzes the color change state of the gas detector tube in the acquired image data, and calculates the gas concentration.

  A gas concentration measurement system according to claim 5 is the gas concentration measurement system according to claim 4, wherein the gas concentration measurement system has a plurality of gas detection tube measurement devices, and the data management means includes a plurality of gas detection tube measurement devices. The gas concentration is calculated based on the transmitted image data.

  According to such a configuration, the data management means can collect gas concentrations at a plurality of points where the gas detector tube measuring device is arranged.

  The gas concentration measuring method according to claim 6, wherein a gas flow step for passing gas through the plurality of gas detection tubes, and a photographing step for photographing the transmitted light images of the plurality of gas detection tubes in order to measure the gas concentration, A transmission step for transmitting the captured image data, a reception step for receiving the transmitted image data, and an image analysis step for calculating the gas concentration by analyzing the received image data.

  According to this procedure, the pump is driven by the gas detection tube measuring device, the gas (atmosphere) to be detected is vented to the plurality of gas detection tubes arranged on the substantially same plane, and the gas detection tube is filled. The detection agent is discolored by reacting the detected detection agent with a gas component to be detected by each gas detection tube contained in the aerated gas. A plurality of gas detector tubes each of which has changed color by reacting with a predetermined gas component are uniformly illuminated by a surface emitting type illumination means, and a transmitted light image transmitted through the gas detector tube is obtained by a camera equipped with a two-dimensional imaging device. Photographed in one image at the same time. The photographed image data is attached to an e-mail using a communication means such as a mobile phone and transmitted to a predetermined e-mail address. The transmitted e-mail is received, for example, by causing a computer to function as a receiving unit, and acquires image data attached to the e-mail. The acquired (received) image data calculates the gas concentration by causing the computer to function as an image analysis unit and analyzing the color change information of the gas detector tube image in the image data.

According to the first aspect of the present invention, the light transmitted through the plurality of gas detector tubes arranged on substantially the same plane is incident on the camera including the two-dimensional image sensor through the casing in which the external light is shielded. A stable image can be taken with a plurality of gas detector tubes by the camera without being affected by surface reflection of the gas detector tubes or uneven illumination.
According to the second aspect of the present invention, since only the transmitted light that has passed through the plurality of gas detection tubes is incident on the camera among the illumination light irradiated from the illumination means, the influence of stray light and the like is further reduced, and the contrast is increased. It is possible to take images of a plurality of gas detection tubes well.
According to the third aspect of the present invention, in photographing a plurality of gas detector tubes using the gas detector tube photographing device by the camera, the camera, the illumination means, and the pump are controlled by the controller. The image can be automatically taken without human intervention.
According to the invention of claim 4 or claim 6, the image data of a plurality of gas detector tubes photographed by the gas detector tube measuring device is transmitted, and the gas concentration is calculated by analyzing the image data on the receiving side. Therefore, even when installing gas detector tube measuring devices at a plurality of locations, it is possible to stably measure a wide range of concentrations of a plurality of gas components without manpower.
According to the fifth aspect of the present invention, the gas concentration measuring system can collect the gas concentration data at each point where a plurality of gas detector tube measuring devices are arranged in the data management computer. It is possible to know the gas concentration distribution without manpower.

DESCRIPTION OF EXEMPLARY EMBODIMENTS The best mode for carrying out the invention will be described below with reference to the drawings.
<Device configuration>
First, an embodiment of a gas concentration measurement system 1 according to the present invention will be described with reference to FIG. Here, FIG. 1 is a diagram for explaining the configuration of the gas concentration measurement system 1.
In the embodiment shown in FIG. 1, three gas detector tube measuring devices 2A, 2B, and 2C are installed. A gas detector tube attached to each gas detector tube measuring device 2A, 2B, 2C and used for gas concentration measurement is a camera having transmission means attached to each gas detector tube measuring device 2A, 2B, 2C ( A transmitted light image of the gas detector tube is taken by a camera-equipped mobile phone. The captured image data of the gas detector tube is attached to an e-mail by the e-mail function of the mobile phone, and the nearest base stations 11A, 11B, 11C of each mobile phone, the telephone company 12, the Internet 13, the LAN (Local Area Network) ) Etc., the data is transmitted to a data management computer (host computer) 20 as data management means. The data management computer 20 acquires image data from the received e-mail, calculates the gas concentration by analyzing the image data, and stores and manages the calculated data.
In the gas concentration measurement system 1, a plurality of gas detector tube measuring devices 2 are arranged in a wide geographical area, and the data management computer 20 collects gas concentration data of each place where the gas detector tube measuring device 2 is arranged. Thus, a gas concentration distribution can be obtained.
The place to be arranged is not limited to a wide area, and may be a specific area, one building, one room, and can be used as a gas concentration distribution measuring system.

  Next, the gas detector tube measuring device 2 and the gas detector tube imaging device 10 according to the present embodiment will be described with reference to FIGS. 2 and 3. Here, FIG. 2 is a side view showing the configuration of the gas detector tube measuring device 2 including the gas detector tube photographing device 10, and FIG. 3 is a perspective view thereof.

  The gas detection tube photographing apparatus 10 includes a housing 101, a controller 102, an illumination unit 103, a pipe 104 a, a pipe 104 b, a light shielding member 105, and a support member 106.

In this embodiment, the casing 101 is made of a black acrylic plate so that a stable image can be obtained with little influence of stray light or the like when photographing the gas detector tube, and the casing 101 is combined with the illumination means 103 described later. The inside of the body 101 constitutes a dark box.
An illuminating means 103 made up of a surface emitting light source is disposed at the bottom of the gas detector tube photographing apparatus 10 so that the upper part can be illuminated uniformly.
A support member 106 that supports a plurality (six) of gas detection tubes 100 used for measurement is disposed above the illumination unit 103, and the plurality of gas detection tubes 100 are arranged on substantially the same plane by the support member 106. Arranged. The support member 106 is formed of a mesh member and transmits illumination light emitted from the illumination unit 103.
Further above, a light shielding member 105 having a slit formed in accordance with the gas detection tube 100 is disposed, and only the transmitted light that has passed through the gas detection tube 100 is selectively introduced into the housing 101.
As described above, the photographing hole 101a for photographing the transmitted light image of the gas detection tube 100 by the camera 110 is formed in the upper part of the casing 101 constituting the dark box, and the camera of the imaging unit 110b of the camera 110 is formed. A positioning member 101b for positioning the installation position of the camera 110 is provided so that the lens fits the shooting hole 101a. The positioning member 101b can be adjusted in position according to the shape of the camera to be used.

  In this embodiment, the illumination unit 103 is arranged at the bottom and the camera 110 is attached to the top. However, the illumination unit 103 may be arranged at the top, and the optical path is landscape. You may comprise as follows.

The gas detector tube measuring device 2 is composed of a gas detector tube photographing device 10, a pump 107, a camera 110 with a transmission means, and a controller 102. By attaching the gas detector tube 100, the gas detector tube 100 is provided. It functions as a detector for the gas to be detected.
That is, by operating the pump 107, the atmosphere (gas) to be measured is passed through the gas detection tube 100, and the gas detection tube 100 that changes color due to the ventilation of the atmosphere is photographed, so that the detection target of the gas detection tube 100 is detected. The gas component is detected.

Since the gas detection pipe measuring apparatus 2 vents the gas (atmosphere) to be measured through the gas detection pipe 100 used for measurement, pipes made of Teflon (registered trademark) are provided on the upstream side and the downstream side of the gas detection pipe 100, respectively. 104a and 104b are provided. These pipes are connected to respective ends of the gas detection tube 100 when the gas detection tube 100 is attached to the gas detection tube measuring apparatus 2. The other end of the upstream side pipe 104a is open to the atmosphere, and the other end of the downstream side pipe 104b is connected to the corresponding pump 107. By operating the pump 107 and suctioning it to the pump side, the atmosphere is sucked from the open end of the upstream pipe 104a, and the air to be measured is vented into the gas detection pipe 100 through the pipe 104a. The gas component to be detected by each gas detection tube 100 in the vented atmosphere reacts with the detection agent, and the detection agent changes color to a length corresponding to the amount of the gas component.
When the pump 107 is stopped, the ventilation of the atmosphere to the gas detection tube 100 is also stopped, and the color change reaction is stopped until the pump 107 is operated again.

  The gas detector tube imaging device 2 includes a controller 102 so as to automatically perform a measurement operation using the gas detector tube 100. The controller 102 includes an MCU (Micro-Controller Unit), and includes a cable 111 for connecting the MCU and the camera 110, a peripheral circuit for controlling ON / OFF of the illumination unit 103 and the pump 107 by the MCU, and the like. Is done. The controller 102 controls the pump 107, the illuminating means 103, and the camera 110, and the gas detector tube measuring apparatus 2 can automatically perform the measurement work. Details of the controller 102 will be described later.

  In a preferred embodiment of the gas detector tube measuring apparatus 2, the image sensing device includes a transmission unit 110c that transmits image data, and the image data of the gas detector tube photographed by the camera 110 is data that is a data management unit using the transmission unit 110c. It transmits to the management computer 20 (refer FIG. 1). In this embodiment, a camera-equipped mobile phone in which a camera (camera body 110a, imaging unit 110b) and transmission unit 110c are integrated is used as the camera 110.

Next, each component means of the gas detection tube measuring apparatus 2 will be described in order.
(Lighting means)
First, the illumination means 103 will be described in detail with reference to FIG. 4A is a side view showing the configuration of the illumination means 103, and FIG. 4B is a perspective view thereof.
The illumination means 103 includes a housing 103a, a cold cathode tube 103b, an inverter 103c, a power cable 103d, and a diffusion plate 103e.
In the present embodiment, the illuminating means 103 constitutes a surface emitting light source having the cold cathode tube 103b as a light source. In order to obtain uniform surface-emitting illumination light, the cold cathode tube 103b is bent in the plane. Further, the light emitted from the cold cathode fluorescent lamp 103b is diffused by the diffusion plate 103e made of a white acrylic plate, and surface-emitting illumination light with excellent uniformity of luminance distribution in the light emitting surface can be obtained.
The electrodes at both ends of the cold cathode tube 103b are connected to an inverter 103c for DC-AC conversion, and emit light by supplying high-voltage, high-frequency AC. The power supply cable 103d of the illumination means 103 is connected to a power supply via a control circuit using a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) so that the controller 102 can control ON (lighting) / OFF (lighting off). The

As such a surface emitting type illumination means 103, for example, a surface emitting cold cathode tube backlight set M-416 manufactured by Akizuki Denshi Co., Ltd. can be used.
Note that the surface emitting type illumination means 103 is not limited to a cold cathode tube as a light source, and an LED (light emitting diode), an organic EL (electroluminescence), or the like may be used as long as the amount of light necessary for photographing can be obtained. A light source may be used.

(camera)
The camera 110 shown in FIGS. 2 and 3 includes a main body 110a, an imaging unit 110b, and a communication unit 110c.
The camera 110 uses a digital camera equipped with a two-dimensional image sensor in order to photograph a plurality of gas detection tubes 100 simultaneously. The imaging unit 110b includes a camera lens and a two-dimensional imaging device, and converts an image formed on the two-dimensional imaging device by the camera lens into an electrical signal (image data). The converted image data is appropriately subjected to AD (analog-digital) conversion and image compression processing in the camera body 110a, and stored in a built-in memory of the camera body 110a (not shown).
In addition, in order to enable simultaneous measurement at a plurality of locations over a wide range, the camera 110 includes a transmission unit 110c and can transmit captured image data. As such a device, there is a mobile phone with a camera, and for example, a mover P506iC manufactured by NTT Docomo can be used. This mobile phone is equipped with a digital camera using a two-dimensional CCD sensor having a number of pixels of 2.0 megapixels, and can perform color photography. Also, it has an e-mail transmission function for attaching image data taken with a digital camera to an e-mail and transmitting it to a designated e-mail address.

  The camera 110 is connected to the controller 102 via the cable 111 and can execute processing such as camera shooting and e-mail transmission according to instructions from the controller 102. The gas detector tube measuring apparatus 2 is manually operated. The measurement process of the gas detection tube 100 can be automatically performed without intervention.

The NTT Docomo mobile phone control procedures are disclosed on the company's website below.
(Reference document)
"Technical reference materials for using mobile phone service (digital) version 3.2", NTT DoCoMo, Inc., June 9, 2004
http://www.nttdocomo.co.jp/binary/pdf/corporate/technology/document/pdc/jidoushadenwa.pdf

  The camera 110 is not limited to a camera-equipped mobile phone, and the camera and the transmission means (communication means) may not be integrated. Further, the transmission means is not limited to a mobile phone, and may be a PHS (Personal Handy-phone System) or other transmission means such as a wireless LAN or a wired LAN.

(Gas detector tube)
The gas detector tube 100 reacts with the gas to be detected and changes its color into a particle having a particle diameter of about several tens of μm made of alumina, silica gel or the like in a glass tube having a constant inner diameter of about several mm to several tens of mm. The detection agent coated with the reagent is filled. By passing the sample gas (atmosphere) from one end of the glass tube, a discoloration layer is formed from the gas introduction end (upstream end) to the exhaust end (downstream end) according to the amount of gas component to be detected. It grows. The length of the discoloration layer is longer as the gas concentration to be detected is higher, and shorter as the gas flow rate (volume) is constant.

  The gas detection tube 100 has a different color depending on the type of detection gas and the color of the detection agent is different. Gas detector tubes are commercially available, for example, No. manufactured by Gastec Corporation. 122P (for toluene), No. 71 (for methyl mercaptan) can be used, and gas detector tubes corresponding to various gases can be used.

(Support member)
The support member 106 is disposed above the illumination unit 103, and supports a plurality (six) of gas detection tubes 100 used for measurement in a substantially flat array. The support member 106 has a box shape with an upper opening, and the gas detection tube 100 can be attached and detached from the upper opening. The support member 106 is formed of a mesh member so that illumination light emitted from the illumination unit 103 can illuminate the gas detection tube 100.

  As long as the support member 106 is configured to transmit illumination light uniformly, the lower surface side may be a transparent member such as a transparent acrylic plate instead of a mesh member, or only the end of the gas detection tube 100. The region of the color changing layer may be configured to be open. Further, the diffusion plate 103e on the upper surface of the illumination unit 103 may also serve as a support member, and the diffusion plate 103e may directly support the gas detection tube 100.

(Light shielding member)
The light shielding member 105 is disposed above the support member 106 and is formed of a black acrylic resin in which a slit is formed in accordance with the gas detection tube 100. The light shielding member 105 selectively introduces only the transmitted light that has passed through the gas detection tube 100 into the housing 101, and reduces the influence of stray light or the like when photographing the gas detection tube.

More preferably, slits are formed in accordance with the filling region of the detection agent necessary for measuring the gas concentration, not the entire transmitted light that passes through the gas detection tube 100, and only the transmitted light that has passed through the filling region of the detection agent is transmitted. You may comprise.
Although the light shielding member 105 is formed of a black acrylic plate, matte coating or matte black paper may be applied to further reduce the influence of stray light.
Similarly, matte coating or matte black paper may be applied to the interior of the housing 101.

(pump)
The pump 107 is connected to the downstream end of the gas detection pipe 100 via a pipe 104 b, and is sucked to the pump side by driving the pump 107, thereby venting the atmosphere into the gas detection pipe 100. The power line of the pump 107 is connected to a DC power source of 5 V via a power MOSFET, and ON (drive) / OFF (stop) is controlled by the controller 102.
The pump 107 connects one pump of the same type to each of the six gas detection tubes 100 and sucks each gas detection tube 100 with an equal suction force.
As long as the pump 107 has a suction force that can suck the plurality of gas detection tubes 100 equally, the six downstream pipes 104b may be assembled and sucked by a single pump.
Further, the drive power source of the pump 107 is not limited to a DC power source, and may be an AC power source. Furthermore, you may comprise so that a some pump may be combined.

(controller)
The controller 102 will be described in detail with reference to FIGS. 5 and 6. Here, FIG. 5 is a circuit diagram showing a configuration of the controller 102, FIG. 6 is a circuit diagram showing a circuit associated with the controller 102, (a) is a reset circuit, (b) is an illumination unit 103 and FIG. A control circuit for connection, (c) is a control circuit for connection with the pump 107.
The controller 102 includes an MCU 102a, a reset circuit 102b, an interrupt input circuit 102c, control circuits 102d and 102e, a switch 102f, a regulator REG, a crystal oscillator CRYSTAL, a resistance element, a capacitor, an LED, and the like.

The MCU 102a is a so-called one-chip microcomputer composed of an arithmetic circuit, a RAM, a flash memory or ROM, an input / output circuit, and the like. In the present embodiment, an 8-bit microcontroller PIC16F84A manufactured by Microchip Technology is used as the MCU 102a.
A crystal oscillator CRYSTAL for generating an operation clock of the MCU 102a and a regulator REG for supplying 5V power are connected to the MCU 102a.
A reset circuit 102b and an interrupt input circuit 102c are connected to the reset signal input terminal (MCLR) and the interrupt signal input terminal (RB0 / INT), respectively. The circuit shown in FIG. 6A is an example of the reset circuit 102b and the interrupt input circuit 102c, and includes a resistance element, a capacitor, a diode, and a switch SW. The reset circuit and the interrupt input circuit output H (High) level from the output terminal (OUT) when the switch SW is open, and output L (Low) level when the switch SW is closed. For example, a push button switch can be used as the switch SW, and the reset signal and the interrupt signal can be input to the MCU 102a by pressing the switch SW of the reset circuit and the interrupt input circuit, respectively.

Returning to FIG. 5, control circuits 102d and 102e for controlling ON / OFF of the pump 107 and the illumination means 103 are connected to the terminals RB1 and RB2, which are other input / output terminals.
FIG. 6B is a circuit diagram illustrating a connection state between the control circuit 102e and the illumination unit 103. The control circuit 102e is composed of a MOSFET and two resistance elements. The ground side of the 12V DC power supplied to the illumination means 103 is grounded via a MOSFET (2SK2231 is used in the circuit diagram). The input terminal (IN) of the control circuit 102e is connected to the input / output terminal RB2 of the MCU 102a, and an H level signal is output from the MCU 102a. When applied to the gate of the MOSFET, a current flows between the drain and source of the MOSFET. The illumination means 103 is turned on (ON). Further, when an L level signal is output from the input / output terminal RB2 of the MCU 102a, the current between the drain and source of the MOSFET of the control circuit does not flow, and the illumination means 103 is turned off (OFF).
FIG. 6C is a circuit diagram showing a state of connection between the control circuit 102d and the pump 107. The ON / OFF control is the same as in the case of the illumination means 103 except that the voltage of the DC power supply supplied to the pump is 5V and the input / output terminal of the MCU 102a connected to the input terminal (IN) of the control circuit 102d is RB1. Since the operation is the same, the description is omitted.

Returning to FIG. 5, the input / output terminals RA0, RA1, and RA2 of the MCU 102a are connected to the camera 110 via the cable 111 (see FIG. 3). The input / output terminals RA0 and RA1 of the MCU 102a are used for data transmission / reception (TX signal, RX signal), and can communicate with the camera 110. By communicating with the camera 110, the MCU 102a can instruct the camera 110 to perform processing such as camera shooting and email transmission.
Further, the terminal RA2 is provided for supplying power to the camera 110, and measurement for a long time is possible without being restricted by the capacity of a built-in battery (not shown) of the camera 110.

A switch 102f is connected to the input / output terminals RB4 to RB7 of the MCU 102a, and a 4-bit data input value can be set by the switch 102f.
In the present embodiment, the switch 102f is a digital switch that displays a numerical value of a set value, but an inexpensive dip switch or the like may be used.

  With the configuration described above, the MCU 102a can control the camera 110, the illumination unit 103, and the pump 107 in accordance with a program stored in a program memory (not shown) in the MCU 102a.

  In this embodiment, an example in which an MCU is used as the controller 102 has been described. However, a general-purpose computer such as a notebook PC (Personal Computer) may be used. In addition, the reset circuit, the control circuit, and the like are not limited to the above-described circuits, and any form can be used as long as the same function is realized.

(Data management computer (data management means))
With reference to FIG. 7, a data management computer (host computer) 20 as data management means will be described. Here, FIG. 7 is a block diagram showing a configuration of functions executed in the data management computer 20.
In the data management computer 20, a program that functions as the mail receiving unit 210, the image data storage unit 211, the image analysis unit 212, and the gas concentration data display unit 213 is executed.
An e-mail attached with image data obtained by photographing a gas detection tube image is transmitted by the gas detection tube measuring device 2A or the like (see FIG. 1). The data management computer 20 uses the mail receiving unit 210 to check whether there is a received mail. If there is a received mail, the data management computer 20 acquires the image data attached to the received mail and stores it in the image data storage unit 211.
The image data stored in the image data storage unit 211 uses the image analysis unit 212 to calculate the gas concentration based on the length of the color change layer of the gas detection tube. The data management computer 20 displays the calculated gas concentration data in the form of a numerical value or a graph using the gas concentration data display means 213 in response to an operator request.

Moreover, since the data management computer 20 can collect the gas concentration at each point where the plurality of gas detector tube measuring devices 20 are arranged, it obtains the gas concentration distribution in the area where the gas detector tube measuring device is arranged. You can also. Then, the gas concentration data display means 213 can be used to display the gas concentration distribution on the map.
Details of each means will be sequentially described.

(Mail receiving means (receiving means))
The mail receiving means 210 sequentially searches the mail address of the e-mail transmitted by each gas detector tube measuring device, and when there is a received mail, acquires the image data attached from the received mail and stores it in the image data storage means 211. Remember.

(Image analysis means)
The image analysis unit 212 will be described with reference to FIG. Here, FIG. 8 is a block diagram showing the configuration of the image analysis means 212.
The image analysis means 212 includes an image data acquisition means 220, a detector tube image cutting means 221, an averaging processing means 222, a difference processing means 223, a moving average processing means 224, a discoloration layer area calculating means 225, The gas concentration calculation unit 226, the blank data storage unit 227, the color change layer area storage unit 228, the calibration curve data storage unit 229, and the gas concentration data storage unit 230 are configured.

  The image analysis unit 212 uses the image data acquisition unit 220 to read (acquire) image data obtained by photographing the gas detection tube from the image data storage unit 211. In addition to the acquisition of the image data, detection target information corresponding to the gas detector tube photographed in the image data is also acquired. This detection target information is information on the type of gas detected by the gas detector tube, and includes information on the color to be changed, information on the size of the gas detector tube, etc., and brightness of the three colors RGB according to the color to be changed Select the optimal color signal from the signal. Further, the size information of the gas detector tube corresponds to the length of the region that is filled with the detection agent and can be changed in color, and the color changeable region of the gas detector tube to be analyzed is appropriately determined in the subsequent detector tube image cutting means 221. Used to cut out accurately.

The detection tube image cutout means 221 cuts out one gas detection tube image to be analyzed from a plurality of gas detection tube images included in the image data. In addition, based on the detection target information described above, a luminance signal having a color suitable for the analysis of the gas detection tube is selected from luminance signals of a color image composed of three colors of RGB.
For example, when the discoloration changes from white to yellow, in the subsequent image analysis process, a B color (Blue) signal having the highest sensitivity to yellow is selected from among the color signals of the image data. Moreover, when changing from white to red, the G color (Green) signal is selected, and when changing to blue, the R color (Red) signal is selected. By selecting an appropriate color signal, it is possible to accurately detect the gas concentration by image analysis.

FIG. 9A shows a state in which the image data as it is (raw image) attached to the e-mail transmitted from the gas detector tube measuring device 2 is displayed on the screen of the data management computer 20. On the screen, images 200a to 200f of six gas detection tubes mounted on the gas detection tube measuring device 2 are displayed.
The image analysis unit 212 sequentially analyzes the six detection tube images 200a to 200f, and instructs the detection tube image cutting unit 221 to cut out one of the images. The detection tube image cutting means 221 cuts out the specified detection tube image. FIG. 9B shows a state where one detector tube image is cut out.

The averaging processing means 222 averages pixel values (luminance signals) in the direction perpendicular to the gas traveling direction for the image data of one cut-out tube image. In FIG. 9B, the horizontal direction indicated by the arrow x is the gas traveling direction. The averaging processing means 222 calculates the pixel value in the range indicated by the arrow Ly in the vertical direction (in the direction of the arrow y) of the gas detector tube image and the average value for each pixel in the range indicated by Lx in the gas traveling direction. To do. That is, assuming that the number of pixels in the horizontal direction and the vertical direction of the detection tube image is Lx and Ly, respectively, the average value of Ly is calculated for Lx sets.
By this averaging process, it is possible to reduce granular noise (image unevenness) in the captured image due to the detection agent being a granular material. As a result of this calculation, data representing the relationship between each position of the detection agent layer and the luminance value can be obtained.

The difference processing unit 223 calculates the difference between the data indicating the relationship between the detection agent layer and the luminance value calculated by the averaging processing unit 222 and the blank data from which an unused (unchanged color) gas detector tube has been imaged. Calculate brightness change due to discoloration. The luminance value obtained by photographing with the camera has the highest luminance value before the color change when the color before the color change is white, and the luminance value decreases because the illumination light is absorbed by the color change. Therefore, by calculating the difference value obtained by subtracting the luminance data after the color change from the blank data before the color change as the luminance change, it can be converted into the luminance change data in which the value before the color change is 0 and the numerical value is increased by the color change.
Also, by calculating the difference from the blank data, it is possible to cancel out noise components such as surface reflection of the gas detector tube and uneven sensitivity of the camera, and to detect the gas concentration with high accuracy.
The blank data can be obtained as data obtained by taking an image in an unchanged color state before the start of measurement and averaging the image by the averaging processing means 222 described above. This blank data is stored in the blank data storage means 227, and is read out and used when analyzing the image data of the gas detector tube whose color has changed.

The moving average processing unit 224 performs moving average processing on the difference data calculated by the difference processing unit 223. Here, the moving average is the data indicating the relationship of the change in luminance with respect to the position x of the detection agent layer, and the position x (unit: pixel = pixel) is shifted pixel by pixel and the luminance value of a predetermined pixel range before and after is shifted. This is filter processing for calculating an average value, and can reduce high spatial frequency noise. That is, it is possible to reduce granular noise due to the granularity of the detection agent in the horizontal direction and other color unevenness of the discoloration layer.
In the present embodiment, a 17th-order moving average filter (which averages luminance change values of eight pixels before and after the center pixel) is used. Note that the size of the moving average filter is not limited to the 17th order, and may be appropriately changed according to the noise level. Further, instead of a simple average of the pixel values to be referred to, a weighted average in which the weight is decreased as the distance from the center pixel is increased may be calculated.

The discoloration layer area calculating unit 225 calculates the discoloration layer area from the data indicating the relationship between the position x of the detection agent layer calculated by the moving average processing unit 224 and the luminance change. A method for calculating the discoloration layer area will be described with reference to FIG. Here, FIG. 10 is a diagram schematically showing the relationship between the position x of the detection agent layer calculated by the moving average processing means 224 and the luminance change in comparison with the gas detection tube.
In FIG. 10, the upper graph is a graph showing the relationship between the position of the detection agent layer in the gas traveling direction (discoloration distance) as x and the luminance change as f (x). The gas detector tube changes color from the left end to the right, and the hatched portion of this graph indicates a discolored region.
fya is an average value of the luminance change when the color is completely changed. On the other hand, in the unchanging color region, the luminance change value is 0 by the above-described difference processing. The area where the luminance change gradually changes in the middle of the graph is an area where discoloration is in progress. In this embodiment, the color change layer area is used instead of the color change length so that the color change amount can be appropriately detected even when the boundary between the color change layer and the uncolor change layer is ambiguous.

  The sum of the luminance change in the entire range of the layer filled with the detection agent is S (area S = discolored layer area in FIG. 10), and the number of product substances reacted in all particles of the detection agent is P [ / cm], the gas concentration is obtained using the fact that there is a proportional relationship (S∝P) between S and P. The discoloration layer area S is calculated by the sectional quadrature method.

Next, the piecewise quadrature method will be described. Δx is the sampling interval [cm / pixel], n is the number of data [pixel], x _i is x _i = Δx × i, the length from the origin with the left end of the detection agent in FIG. 10 as the origin, and f (x _i ) _{Assuming that} the luminance change at x _i is S and the area of the shaded area in FIG. 10 is S, S can be obtained from equation (1).

The discoloration layer area calculation unit 225 outputs the calculated discoloration layer area to the gas concentration calculation unit 226 and stores it in the discoloration layer area storage unit 228.
This image analysis technique is disclosed in detail in Non-Patent Document 1 described above by the present inventors.

  The gas concentration calculation means 226 reads the color change layer area data calculated by the color change layer area calculation means 225 and the previous or / and previous color change layer area data stored in the color change layer area storage means 228 to calculate the color change speed. Then, the gas concentration is calculated with reference to the calibration curve data representing the relationship between the color changing speed and the gas concentration stored in advance in the calibration curve data storage means 229. The calculated gas concentration data is stored in the gas concentration data storage means 230.

The procedure for calculating the gas concentration will be described with reference to the drawings as appropriate.
First, an example of an experiment in which toluene gas is used as a detection target gas will be described as a method for creating calibration curve data indicating the relationship between the color change rate and the gas concentration.
First, 100 ppb of toluene gas was packed in a sampling bag (manufactured by GL Science Co., Ltd., made of fluororesin). The gas concentration was confirmed using a PID detector (Photo Ionization Detector, REA model PGM-7240). Introduce the toluene gas in the sampling bag into the gas detector tube (Gastech, Gas detector tube No.122P for toluene) at a constant ventilation rate, take images of the gas detector tube at appropriate intervals, and change the color according to the procedure described above. The layer area was calculated. In addition, since the used toluene gas detector tube changes its color from white to brown, a B color signal is used.
FIG. 16 shows the experimental results. It can be seen that the discolored layer area increases at a constant rate in proportion to the ventilation time. Here, the rate of increase of the color changing layer area (hereinafter referred to as the color changing rate), which is the slope of the graph, depends on the gas concentration. This dependency will be described in the next experiment.
It should be noted that the increase in the discoloration layer area is saturated when the ventilation time is about 20 minutes, because this is because the color has changed to the end of the gas detection tube.

Next, the results of measuring the relationship between the aeration time and the discolored layer area with respect to various concentrations of toluene gas are shown in FIG. The color change layer area increases linearly with the ventilation time, and when the color changes to the end of the gas detector tube, the color change layer area is saturated. It can be seen that the color change rate depends on the density.
From this experimental result, the slope of the portion where the color changing layer area changes linearly for each gas concentration was calculated as the color changing speed of that concentration. FIG. 18 shows the relationship between the toluene gas concentration thus obtained and the color change rate. In this method of calculating the gas concentration from the discoloration rate, it was found that measurement up to 16 ppb indicated by an arrow in the figure was possible.

Returning to FIG. 8, in this embodiment, the relationship between the gas concentration and the color change rate is obtained in advance for various gases to be detected as calibration curve data, and stored in the calibration curve data storage unit 229. Remember.
The gas concentration calculation unit 226 calculates a color change rate from the color change layer area data newly calculated by the color change layer area calculation unit 225 and the color change layer area data at the previous measurement, and uses the calibration curve data to calculate the color change rate. The gas concentration corresponding to the color change rate is calculated. The calculated gas concentration data is stored in the gas concentration data storage unit 230.
In the color change speed calculation, the color change speed may be calculated by referring to the past measurement value instead of referring only to the previous measurement value.

(Gas concentration data display means)
Returning to FIG. 7, the gas concentration data display means 213 calculates the gas concentration data calculated by the image analysis means 212 and stored in the gas concentration data storage means 230 (see FIG. 8) of the image analysis means 212 according to the operator's request. Display on the screen of the data management computer accordingly.
FIG. 19 shows a display example of the gas concentration measurement result. For the gas concentration, a measurement period and a rest period were set at intervals of about 15 minutes, and the measurement was repeated at intervals of about 1 minute during the measurement period. Also, the pump was stopped during the suspension period to prevent the gas detector tube from discoloring.
Then, according to the operator's instruction input via an input means such as a keyboard or mouse (not shown) of the data management computer 20, the gas concentrations at A, B and C3 surrounded by the two-dot chain line are calculated according to the procedure described above. And it is displayed on the graph which shows a time-dependent change of a discoloration layer area.
The display format is not limited to the example shown in FIG. 19, and printing may be performed by connecting a printer instead of the screen display.

  Moreover, the gas concentration measuring system 1 can arrange | position the several gas detection tube measuring apparatus 2, and can measure the gas concentration of a geographically wide place. Then, the data management computer 20 can display a map including the measurement points using the gas concentration data display means 213 and also display the gas concentration value for each measurement point. Further, based on the collected gas concentration data at a plurality of points, for example, an isoconcentration line can be created by using a computer graphics method and displayed on a map so that the gas concentration distribution can be visually easily understood. .

<Operation of the device>
(Operation of gas concentration measurement system)
With reference to FIG. 11, the operation of the gas concentration measurement system 1 shown in FIG. 1 according to the embodiment of the present invention will be described. Here, FIG. 11 is a flowchart showing a processing flow of the gas concentration measurement system 1.
In the configuration example shown in FIG. 1, the gas concentration measurement system 1 includes three gas detector tube measuring devices 2 (2A, 2B, 2C) and one data management means (data management computer) 20. However, the gas detector tube measuring device 2 may be one, or a plurality of two or more may be used.

First, the description starts from the measurement operation by the gas detector tube measuring device 2 (see FIG. 2). The gas detector tube measuring device 2 drives the pump 107 under the control of the controller 102 to vent the atmosphere through the gas detector tube 100 attached to the gas detector tube measuring device 2 (step S10).
Next, the gas detection tube measuring apparatus 2 captures a transmitted light image of the gas detection tube 100 using the camera 110 at a predetermined timing in accordance with the control of the controller 102 (step S11). Note that the controller 102 controls the lighting unit 103 to be lit when photographing.
The gas detection tube measuring apparatus 2 uses the transmission unit 110c to attach the image data captured by the camera 110 to an e-mail and transmit it to an e-mail address that can be received by the data management computer 20 (step S12).

  When an e-mail system is used as the image data transmission and reception means, the e-mail transmitted from the gas detector measuring device 2 is stored in a predetermined mail server, and the data management computer 20 on the receiving side Since the e-mail received at an arbitrary timing can be received, each gas detector tube measuring device 2 (2A, 2B, 2C) and the data management computer 20 can operate asynchronously.

On the other hand, the data management computer 20 (see FIG. 7) receives the image data transmitted from the gas detector tube measuring apparatus 2 using the mail receiving means 210 which is the receiving means for receiving the image data, and is attached. Image data is acquired (step S20). The acquired image data is stored in the image data storage unit 211.
The data management computer 20 reads the image data stored in the image data storage unit 211, analyzes the image data using the image analysis unit 212, and calculates the gas concentration (step S21).
The data management computer 20 displays the calculated gas concentration data on a screen (not shown) of the data management computer 20 in response to an operator's request using the gas concentration data display means 213 (step S22).

Each gas detection tube measuring device 2 repeatedly performs the measurement operation (step S10 to step S12) of the gas detection tube 100 as appropriate according to the settings of the respective controllers 102.
Further, the data management computer 20 repeatedly executes processing (step S20 to step S22) including reception of image data, image analysis of the image data, and display of gas concentration data as necessary. To do.

(Operation of gas detector tube measuring device)
Next, with reference to FIG. 12, the operation of the gas detector tube measuring apparatus 2 according to the embodiment of the present invention shown in FIGS. 2 and 3 will be described in detail. Here, FIG. 12 is a flowchart showing a processing flow of the gas detector tube measuring apparatus 2.
In the present embodiment, the gas detector tube measuring apparatus 2 is controlled by the controller 102 so as to alternately repeat a predetermined number of continuous measurements and a predetermined period of pause.

First, when the power is turned on by a power switch (not shown) of the gas detection tube measuring apparatus 2, the MCU 102a of the controller 102 reads out a program from a built-in program memory and executes processing according to the program. After the power is turned on, the MCU 102a reads the set value by the switch 102f connected to the terminals RB4 to RB7 and inputs it to the variable T (step S100).
Next, the MCU 102a outputs an L level to the terminals RB1 and RB2, maintains the pump 107 and the illumination means 103 in the OFF state via the control circuits 102d and 102e, respectively, and sets the T value input in step S100 to the counter variable Toff. Substitute (step 101).

  Thereafter, the MCU 102a delays for a predetermined time (continues the idle state for a predetermined time) (step S102), and checks whether an interrupt signal is input by the interrupt input circuit 102c (step S103). If no interrupt signal is input (No in step S103), the value of the counter variable Toff is decremented by 1 (step S104), and it is confirmed whether the value of the counter variable Toff has become 0 (step S106). If the counter variable Toff is not 0 (No in step S106), the process returns to step S102, and a predetermined time delay (step S102) and interrupt signal confirmation (step S103) are repeated. Here, considering a case where no interrupt signal is input (step S103 is always No), the delay (step S102) is repeated until the counter variable Toff becomes 0, that is, the set T times. Here, considering a case where 1 minute is set as the delay time, for example, if 15 is set as the T value, the delay is delayed by 15 minutes. That is, for 15 minutes, the gas detection tube measuring apparatus 2 continues to be in a resting state. The processing flow when there is an interrupt signal (Yes in step S105) will be described later. When T delays are performed, the counter variable Toff is also counted down T times to 0 (Yes in step S106), and the process proceeds to step S107.

  In step S107, the MCU 102a outputs an H level to the terminals RB1 and RB2, turns on the pump 107 and the illumination unit 103 via the control circuits 102d and 102e, respectively, and assigns the T value to the counter variable Ton. Next, the MCU 102a electronically captures the image of the gas detection tube 100 to the camera 110 and the image data obtained by photographing from the terminals RA0 and RA1 for communication with the camera 110 via the cable 111 (see FIG. 3). The camera 110 is attached to the mail and instructed to be transmitted to a predetermined mail address, and the camera 110 executes image shooting and mail transmission (step S108).

  Next, the MCU 102a confirms whether or not an interrupt signal is input by the interrupt input circuit 102c (step S109). If no interrupt signal is input (No in step S109), the value of the counter variable Ton is determined. Is decremented by 1 (step S110), and it is checked whether the value of the counter variable Ton has become 0 (step S112). If the counter variable Ton is not 0 (No in Step S106), the process returns to Step S108, the photographing of the gas detection tube by the camera 110, the transmission process of the e-mail attached with the image data (Step S108), and the interruption signal Confirmation (step S109) is repeated. Here, as in step S103, considering that no interrupt signal is made (step S109 is always No), until the counter variable Ton becomes 0, that is, shooting by the camera and e-mail only for the set T times. A continuous measurement state in which the transmission process (step S108) is repeated is entered. For example, when 15 is set as the T value, photographing by the camera 110 and mail transmission, that is, measurement of the gas detection tube 100 is repeated. When T measurements are performed, the counter variable Ton is counted down T times to 0 (Yes in step S112), and the process returns to step S101. In step S101, the pump 107 and the illumination means 103 are turned off and enter a rest state for a predetermined time consisting of steps S102 to S106.

  Here, when the MCU 102a detects the input of the interrupt signal in step S103 during the dormant state (Yes in step S103), the MCU 102a assigns 0 to the counter variable Toff and sets the T value set by the switch 102f. Re-input (step S105). Since 0 is input to the counter variable Toff, the process branches to Yes in the next step S106, the pump 107 and the illumination means 103 are turned on (step S107), and the process consists of steps S108 to S112 according to the new T value. Transition to the continuous measurement state.

  If the MCU 102a detects the input of an interrupt signal in step S109 during the continuous measurement state consisting of step S107 to step S112 (Yes in step S109), the MCU 102a assigns 0 to the counter variable Ton and also sets the switch 102f. The T value set by is input again (step S111). Since 0 is input to the counter variable Ton, the process branches to Yes in the next step S112, the pump 107 and the illumination unit 103 are turned off (step S101), and a transition is made to a rest state according to the new T value.

The input of this interrupt signal is an operation performed when the operator wants to change the measurement interval during automatic measurement by the gas detector tube measuring device 2. That is, the measurement operation according to the new T value can be started by changing the setting of the switch 102f and inputting the interrupt signal via the interrupt input circuit 102c.
Further, when a reset signal is input via the reset circuit 102b, the MCU 102a interrupts the process regardless of which step is being executed, and resumes the execution from step S100 similarly to when the power is turned on.

(Operation of data management computer)
Next, the operation of the data management computer 20 will be described with reference to FIG. FIG. 13 is a flowchart showing the flow of processing of the data management computer 20 shown in FIG.
The data management computer 20 executes mail receiving processing by the mail receiving means 210, checks whether or not an e-mail from the gas detector tube measuring apparatus 2 has been received, and if there is an e-mail received, The image data attached to the mail is acquired and stored in the image data storage unit 211 (step 200).
Next, the data management computer 20 reads out the image data stored in the image data storage unit 211 using the image analysis unit 212, analyzes the image, calculates the gas concentration, and calculates the calculated gas concentration data. Is stored in the gas concentration data storage means 230 (see FIG. 8) (step S201).

  When the gas concentration is calculated (step S201), the data management computer 20 confirms whether or not there is a request for displaying the gas concentration data via an input means such as a keyboard (not shown) from the operator (step S202). When requested (Yes in step S202), the gas concentration data display means 213 is used to read the gas concentration data stored in the gas concentration data storage means 230 (see FIG. 8), and the data management computer 20 is not shown. It is displayed on the display screen (step S203). When the display of the gas concentration data ends, the data management computer 20 returns to the mail reception process (step S200) again. If there is no request for displaying gas concentration data (No in step S202), the data management computer 20 returns to the mail reception process (step S200) without displaying the gas concentration data.

(Operation of mail receiving means (receiving means))
Next, the mail reception process (step S200) shown in FIG. 13 will be described in detail with reference to FIG. Here, FIG. 14 is a flowchart showing the flow of processing of the mail receiving means 210 shown in FIG.
In the present embodiment, nine gas detector tube measuring devices 2 are in operation, and each gas detector tube measuring device 2 transmits an e-mail attached with image data to a corresponding predetermined e-mail address. To do.

  The mail receiving means 210 first substitutes 0 for all elements (i = 1 to 9) of the array variable fail [i] (step S300). Here, the array variable fail [i] is a variable that counts the number of times the acquisition of the e-mail from the i-th gas detector tube measuring device 2 has failed.

  First, in order to obtain an e-mail from the first gas detection tube measuring apparatus 2, 1 is set to the variable i (step S301). Next, it is confirmed whether i is 9 or less (step S302). If it is 9 or less (Yes in step S302), the gas detection tube measuring apparatus 2 having the number set in the variable i sends an e-mail. Connect to the address (step S303). It is confirmed whether there is an e-mail at the connected mail address (step S304). If there is an e-mail (Yes in step S304), the e-mail is received and the corresponding array variable element fail [i] is set to 0. Is substituted to clear the number of failures (step S305). Next, image data attached to the acquired e-mail is acquired (step S306), and the image data is stored in a predetermined folder provided for each gas detector tube measuring device 2 of the image data storage unit 211 (step S306). S307). Then, the e-mail whose image data has been acquired is deleted (step S308). 1 is added to the variable i (step S309), and the process returns to step S302. If the variable i is 9 or less (Yes in step S302), the e-mail is received from the gas detector measuring device 2 with the next number i. It progresses to a process (step S303). Thereafter, similarly, the process of receiving e-mails from the gas detector tube measuring apparatuses 2 of number 1 to number 9 is sequentially performed.

  In step S304, when i is larger than 9 (No in step S304), the process of receiving an e-mail from the gas detector measuring device 2 has been completed, so wait for 75 seconds (step S310). The variable i is set to 1 (step S301), and the process of receiving an e-mail from the first gas detector tube measuring apparatus 2 is repeated. Here, the standby time of 75 seconds corresponds to the measurement interval of the gas detector tube measuring apparatus 2, and when the measurement interval is changed, the standby time may be set as appropriate.

  If no e-mail is received in step S304 (No in step S304), 1 is added to the corresponding array variable element fail [i] (step S311), and the array variable element fail [i] is It is confirmed whether it is 5 or less (step S312). Step S312 confirms whether or not the cumulative number of failed e-mail acquisitions is 5 or less. If the cumulative number is 5 or less (Yes in step S312), the e-mail acquisition of that number i is skipped, i is advanced by 1 (step S309), and the gas detector tube measuring device 2 corresponding to the next number is sent. Receive email from.

  On the other hand, when the cumulative number of failures reaches 6 (No in step S312), the data management computer 20 stops the processing by the mail receiving unit 210.

  In the present embodiment, each gas detector tube measuring device 2 transmits an e-mail attached with image data to a different e-mail address for each measuring device, but one common e-mail address is used. The data management computer 20 confirms information such as the sender of each e-mail and the title of the e-mail to determine which gas detector tube measuring apparatus 2 is the e-mail. It may be.

(Operation of image analysis means)
Next, the image analysis process (step S201) shown in FIG. 13 will be described in detail with reference to FIG. Here, FIG. 15 is a flowchart showing the flow of processing of the image analysis means 212 shown in FIG.
The image analysis unit 212 reads and acquires the image data stored from the image data storage unit 211 by the image data acquisition unit 220 (step S400). From the acquired image data, one image is cut out from a plurality of gas detector tube images included in the image data using the detector tube image cutting means 221 (step S401). The averaging processing means 222 averages pixel values in the direction perpendicular to the gas traveling direction on the cut out image of one gas detector tube (step S402), and the averaged image data is converted into the averaged image data. On the other hand, the difference processing unit 223 is used to calculate a difference value from the blank data stored in the blank data storage unit 227 (step S403). Further, moving average processing is performed on the difference value data using the moving average processing unit 224 (step S404), and the color changing layer area calculating unit 225 is used to calculate the color changing layer area from the data subjected to the moving average processing. The calculated discoloration layer area data is output to the gas concentration calculation means 226 and stored in the discoloration layer area storage means 228 (step S405).

  The image analysis unit 212 uses the gas concentration calculation unit 226 to change the color change layer area data calculated by the color change layer area calculation unit 225 and the previous or / and previous time stored in the color change layer area storage unit 228. The color change rate is calculated based on the color change layer area data, the gas concentration is calculated with reference to the calibration curve data stored in the calibration curve data storage unit 229, and the calculated gas concentration data is stored in the gas concentration data storage unit 230. Store (step S406).

  If there remains an image of the gas detection tube whose gas concentration is to be calculated (Yes in step S407), the process returns to step S401, and the gas concentration calculation processing (step S401 to step S406) for the next gas detection tube is repeated. If there is no unprocessed gas detector tube image (No in step S407), the processing by the image analysis means 212 is terminated.

  In the present embodiment, the gas concentration is calculated based on the color change rate, but at least two times of measurement data (color change layer area data) are required to obtain the color change rate. Therefore, when one or more past measurement data (color change layer area data) is not stored in the color change layer area storage unit 228 (when calculating the first color change layer area), the image analysis unit 212 calculates the gas concentration. The gas concentration by means 226 is not calculated. Alternatively, the data management computer 20 confirms that the image data corresponding to each gas detector tube measuring device 2 has been acquired twice or more by the mail receiving means 210, and then the image analysis processing (gas concentration) by the image analysis means 212. You may control to perform a calculation process.

<Experimental example>
Next, the luminance distribution of the transmitted light image of the gas detector tube photographed using the gas detector tube measuring apparatus 2 according to the present invention and the reflected light image of the gas detector tube photographed by illuminating from the direction of the camera as a comparative example. The luminance distribution is shown in FIGS. 20 and 21, respectively.

Each experimental condition is shown.
(Transmission light image)
Illumination means:
Surface emitting cold cathode tube (Akizuki Electronics Co., Ltd., surface emitting cold cathode tube backlight set M-416)
camera:
Mobile phone with camera (NTT Docomo, Mova P506iC)
Use B color signal Gas detector tube:
Gas detector tube for toluene (Gastec Corporation, Gas detector tube No. 122P)

(Reflected light image (comparative example))
Illumination means:
Fluorescent lamp (Matsushita Electric Industrial Co., Ltd., twin fluorescent lamp FPL27EX-N, length 245 mm)
The learning desk lamp equipped with the above-mentioned fluorescent lamp was used to illuminate with the fluorescent tube arranged approximately parallel to the axial direction of the gas detection tube at substantially the same height as the camera.
Camera, gas detector tube:
Other than the camera, the gas detection tube, and the illumination means, the same configuration as that for the transmitted light image was used.

The gas detector tube for toluene turns from white to brown. 20 and FIG. 21, the position x [pixel] of the gas detector tube indicated by “brown” by the arrow is a layer that has changed to brown by reacting with toluene gas from 0 to 40, and “white” The range indicated by is an unreacted and discolored layer.
In FIG. 20, both the brown region on the left side of the graph and the white region on the right side of the graph show almost flat values except for the position x that is the boundary of discoloration between 40 and 60.
On the other hand, in FIG. 21, the brightness level of the white region where the position x is 80 to 100 is increased by about 30 to 40 compared to the white region where the position x is 60 to 80. This is because in this area, the illumination light is regularly reflected on the glass surface of the gas detector tube and is incident on the camera. With reflective illumination, it is difficult to capture stable images over the entire area to be imaged. Yes.
As shown in FIG. 20, when a transmitted light image is captured using surface-emitting illumination, it can be seen that stable image capturing can be performed on the entire surface of the capturing target region.

It is a block diagram which shows the structure of the implementation environment using the gas concentration measurement system which concerns on embodiment. It is a side view which shows the structure of the gas detection tube measuring apparatus containing the gas detection tube imaging device which concerns on embodiment. It is a perspective view which shows the structure of the gas detection tube measuring apparatus containing the gas detection tube imaging device which concerns on embodiment. It is the side view and perspective view which show the structure of the surface emitting light source of the gas detector tube imaging device which concerns on embodiment. It is a circuit diagram which shows the connection of the controller of the gas detector tube measuring apparatus which concerns on embodiment, and its control object. It is a circuit diagram which shows the peripheral circuit of the controller of the gas detector tube measuring apparatus which concerns on embodiment. (A) is a reset circuit (interrupt input circuit), (b) is a control circuit for controlling the illumination means, and (c) is a control circuit for controlling the pump. It is a block diagram which shows the structure of the data management computer (data management means) of the gas concentration measurement system which concerns on embodiment. It is a block diagram which shows the structure of the image analysis means of the gas concentration measurement system which concerns on embodiment. It is a figure for demonstrating the image analysis by an image analysis means. (A) is the raw image which image | photographed the gas detection tube transmitted from the gas detection tube measuring apparatus, (b) is an image which shows a mode that one gas detection tube image was cut out. It is a figure for demonstrating the calculation method of the discoloration layer area of a gas detection tube. It is a flowchart which shows the flow of a process of the gas concentration measurement system which concerns on embodiment. It is a flowchart which shows the flow of a process of the gas detector tube measuring apparatus which concerns on embodiment. It is a flowchart which shows the flow of a process of the computer for data management (data management means). It is a flowchart which shows the flow of a process of a mail receiving means. It is a flowchart which shows the flow of a process of an image analysis means. It is a graph which shows the experimental result which investigated the relationship between the ventilation time of toluene gas, and a discoloration layer area. It is a graph which shows the experimental result which investigated the gas concentration dependence of the relationship between the ventilation time of toluene gas, and a discoloration layer area. It is a graph which shows the relationship between toluene gas density | concentration and a discoloration speed | rate. It is drawing which shows a mode that the gas concentration measurement result in the painting factory was displayed on the screen. It is a graph which shows the luminance distribution of the image which image | photographed the gas detection tube by the gas detection tube measuring apparatus which concerns on embodiment. It is a graph which shows the luminance distribution of the image which image | photographed the gas detection tube with the conventional method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas concentration measuring system 2, 2A, 2B, 2C Gas detector tube measuring device 10 Gas detector tube imaging device 20 Data management computer (data management means)
DESCRIPTION OF SYMBOLS 100 Gas detection tube 101 Case 101a Image | photographing hole 102 Controller 103 Illumination means 104a, 104b Piping 105 Light shielding member 106 Support member 107 Pump 110 Camera 110a Camera body 110b Imaging unit 110c Transmission means 210 Mail reception means (reception means)
212 Image analysis means

Claims (6)

A gas detector tube imaging device for measuring gas concentration by analyzing an image captured by a camera equipped with a two-dimensional imaging device for transmitted light that passes through a gas detector tube,
A support member for arranging a plurality of the gas detection tubes on the same plane;
A surface emitting type illumination means for illuminating the plurality of gas detection tubes supported by the support member;
A housing that shields from the outside light a space between the illumination unit and the camera that captures the transmitted light through which the illumination light from the illumination unit passes through the plurality of gas detection tubes;
A gas detector tube photographing device characterized by comprising:   2. The gas detection according to claim 1, wherein a light shielding member that selectively transmits the transmitted light that passes through the plurality of gas detection tubes is provided between the plurality of gas detection tubes and the camera. Tube photographing device. The gas detector tube photographing device according to claim 1 or 2,
A camera equipped with a two-dimensional image sensor;
A pump for venting gas through the plurality of gas detection tubes;
A controller for controlling photographing of the camera, turning on and off of the illumination means, and driving and stopping of the pump;
A gas detector tube measuring apparatus comprising: The gas detector tube measuring device according to claim 3, further comprising a transmitting unit that transmits image data of the plurality of gas detector tubes photographed by the camera.
A data managing means comprising: a receiving means for receiving the image data transmitted by the transmitting means; and an image analyzing means for calculating a gas concentration by analyzing the image data received by the receiving means;
A gas concentration measurement system comprising: A plurality of gas detector tube measuring devices;
The data management means calculates a gas concentration based on image data transmitted from the plurality of gas detector tube measuring devices;
The gas concentration measurement system according to claim 4. A gas concentration measurement method using a gas detector tube,
A ventilation step for venting gas to the plurality of gas detection tubes arranged in the same plane;
An imaging step of illuminating the plurality of gas detection tubes with a surface emitting type illumination means, and photographing the transmitted light that passes through the plurality of gas detection tubes with a camera including a two-dimensional imaging device;
A transmission step of transmitting image data of the plurality of gas detection tubes photographed by the camera;
A receiving step of receiving the transmitted image data;
An image analysis step of analyzing the received image data and calculating a gas concentration;
A gas concentration measurement method comprising:

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