JP6786067B2 - Spectral device and reflection spectrum junction processing method - Google Patents

Description

The present invention relates to a spectroscopic device used for mineral exploration activities and the like.

In mineral exploration activities, the distribution of minerals on the ground surface is investigated by various methods. Among the mineral exploration methods, there is an image analysis method that applies remote sensing technology. This is a method of analyzing satellite images captured by artificial satellites. It acquires the reflection spectrum of light reflected on the ground surface, and minerals within the imaging range from the reflection spectrum pattern (hereinafter, "spectral pattern"). This is a method for identifying the type and distribution of light. Mineral identification is performed by collating the spectral pattern obtained from the satellite image with a database called a library in which master data of the spectral pattern of the mineral is recorded.

On the other hand, the reflection of light on the surface of the mineral whose reflection spectrum is to be measured differs depending on whether it is, for example, lumpy, clay-like, or powdery. That is, even if the same mineral is used, the spectral pattern differs slightly depending on the state of the mineral. In addition, other minerals existing in the vicinity may affect each other and the spectral pattern may differ. For this reason, in order to carry out accurate mineral exploration with satellite images, field verification is performed, and information on the spectral pattern obtained from satellite images and information on the actual state of minerals and the existence of other minerals in the field are provided. It is important to keep them tied together. By accumulating such information in the database, it becomes possible to identify minerals more realistically in the subsequent mineral exploration based on satellite images.

As a conventional technique for acquiring a spectral pattern, there is a spectroscopic device described in Patent Document 1. In the spectroscope of Patent Document 1, a detection head provided with a light source and an optical fiber irradiates a sample with light, and the reflected light is sent to the spectroscope via the optical fiber to acquire a spectrum pattern.

Japanese Unexamined Patent Publication No. 2004-309314

Characteristic parts appear in the near-infrared and mid-infrared wavelength regions in the spectral patterns of various minerals. For example, FIG. 1 is a diagram showing an example of a mineral spectrum pattern, and in the spectrum pattern of this mineral, characteristic portions appear in the wavelength regions near 1400 nm and 2200 nm. As described above, it is necessary to acquire the reflection spectrum in a wide wavelength range in order to identify the mineral.

On the other hand, it has been difficult to measure the reflection spectrum in a wide wavelength range as shown in FIG. 1 with one spectroscope due to the limitation of the performance of the diffraction grating of the spectroscope in the spectroscopes generally on the market. Further, even with a spectroscope capable of measuring the reflection spectrum in a wide wavelength range, the measurement accuracy is lowered in the wavelength range near the upper limit and the lower limit of the measurable wavelength range, and it is difficult to obtain the actual spectrum pattern of the mineral. Met. For this reason, conventionally, a plurality of spectroscopic devices having different measurable wavelength ranges are prepared for the mineral to be measured, the reflection spectra are measured by each spectroscopic device, and these reflection spectra are joined into one to form a spectrum pattern. I had acquired it.

However, when measuring the reflection spectrum with a plurality of spectroscopes, it is difficult to make the measurement conditions exactly the same, and each time the reflection spectrum is measured by each spectroscope, the position shift of the measurement point and the amount of incoming light There were differences. That is, even if the reflection spectra measured by each spectroscope are joined, the obtained spectrum pattern is strictly different from the spectrum pattern obtained under the same measurement conditions, which means that the mineral identification accuracy is high. It becomes a factor to decrease.

The present invention has been made in view of the above circumstances, and an object of the present invention is to accurately measure the reflection spectrum of a measurement object and improve the identification accuracy of the measurement object.

The present invention that solves the above problems is a spectroscopic device that measures the reflection spectrum of an object to be measured, and includes a probe that incorporates a light source that irradiates the object to be measured with light and captures the light reflected by the object to be measured. A guide that connects a spectroscope body having a plurality of spectroscopes having different possible wavelength ranges from each other, the probe and the spectroscope body, and distributes the reflected light of the measurement object taken in from the probe to each spectroscope. The control unit includes an optical path and a control unit that performs bonding processing of the reflection spectrum acquired by each spectroscope, and the control unit cuts off the disturbance portion on the upper limit side of the wavelength region of the first spectrum to obtain the junction wavelength upper limit value. The disturbance portion on the lower limit side of the wavelength range of the second spectrum is cut off to set the lower limit of the wavelength of the junction, and the second wavelength range within the range of the upper limit of the wavelength of the junction and the lower limit of the wavelength of the junction is set. The average value of the reflectance of one spectrum is calculated to set the first spectrum average value, and the reflection of the second spectrum in the wavelength range within the range of the upper limit of the wavelength of the junction and the lower limit of the wavelength of the junction. The average value of the rate is calculated to set the second spectrum average value, and the reflectance value of either one of the first spectrum and the second spectrum is referred to as the first spectrum average value. It is corrected so that it matches the second spectral average value and the spectral pattern does not change, and is corrected in the wavelength range within the range of the upper limit value of the junction wavelength and the lower limit value of the junction wavelength. It is characterized in that it is configured to control joining one spectrum and the other spectrum.

From another point of view, the present invention is a method for joining reflection spectra of reflection spectra measured by a plurality of spectroscopes, in which the disturbance portion on the upper limit side of the wavelength range of the first spectrum is cut off to obtain the junction wavelength. The upper limit is set, the disturbance portion on the lower limit side of the wavelength region of the second spectrum is cut off to set the junction wavelength lower limit, and the wavelength within the range between the junction wavelength upper limit and the junction wavelength lower limit. The average value of the reflectance of the first spectrum is calculated in the region to set the first spectral average value, and the second spectrum is set in the wavelength region within the range of the junction wavelength upper limit value and the junction wavelength lower limit value. The average value of the reflectance of the spectra is calculated to set the second spectrum average value, and the value of the reflectance of either one of the first spectrum and the second spectrum is set to the first spectrum. Corrected so that the average value and the second spectral average value match and the spectral pattern does not change, and in the wavelength range within the range of the junction wavelength upper limit value and the junction wavelength lower limit value. , It is characterized by joining one corrected spectrum and the other spectrum.

According to the present invention, it is possible to accurately measure the reflection spectrum in a wide wavelength range with one spectroscope. This makes it possible to improve the identification accuracy of the measurement object.

It is a figure which shows an example of the spectral pattern of a mineral. It is a perspective view which shows the schematic structure of the spectroscopic apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows the schematic structure of the probe which concerns on embodiment of this invention. It is a schematic diagram which shows the state which the light shielding ring of the probe which concerns on embodiment of this invention is closed. It is a block diagram which shows the schematic structure of the spectroscopic apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows the distribution structure of the optical fiber which concerns on embodiment of this invention. It is a figure which shows the two reflection spectra acquired by the spectroscopic apparatus which concerns on embodiment of this invention. It is a figure which shows the outline of the control flow of the general spectrum joining processing method. It is a figure which shows the spectrum which joined by the general spectrum joining processing method. It is a figure which shows the outline of the control flow of the spectrum joining processing method which concerns on embodiment of this invention. It is a figure explaining the procedure of the spectrum bonding processing method which concerns on embodiment of this invention. It is a figure explaining the procedure of the spectrum bonding processing method which concerns on embodiment of this invention. It is a figure explaining the procedure of the spectrum bonding processing method which concerns on embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the present specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals to omit duplicate description.

As shown in FIG. 2, the spectroscope 1 according to the present embodiment includes a probe 10 for irradiating the measurement target mineral with light, a spectroscope main body 20 for measuring the reflection spectrum of the light reflected by the measurement target mineral, and the probe 10. An optical fiber cable 30 for connecting the spectroscopic apparatus main body 20 is provided.

The housing 21 of the spectroscopic apparatus main body 20 is provided with a recess 22 formed so as to be recessed one step with respect to the outermost surface. One end of the optical fiber cable 30 is connected to the tip of the probe 10 slightly from the center, and the other end is connected to the spectroscope main body 20 in the recess 22. By connecting the optical fiber cable 30 in the recess 22 in this way, it is possible to suppress inadvertent contact with the connector when handling the probe 10, and it is possible to suppress damage to the connector. Further, one end of the power cable 11 of the probe 10 is connected to the rear end of the probe 10, and the other end is connected to the recess 22 of the spectroscopic device main body 20. A power cable (not shown) is also connected to the spectroscope main body 20, and power is supplied from the outside. Further, the probe 10 is provided with a trigger button 12, and when the trigger button 12 is pressed down, the measurement of the reflection spectrum is started.

As shown in FIG. 3, a light source 13 is provided inside the probe 10. The type of the light source 13 is not particularly limited as long as it can emit light in a wide wavelength range. For example, an incandescent lamp whose spectral distribution of emitted light is close to that of blackbody radiation can be mentioned, and even an incandescent lamp can have a high color temperature and has a long life. It is more preferable to use a long halogen lamp. The optical fiber cable 30 is fixed at an angle of, for example, about 40 ° to the optical axis of the light source 13, and is attached to the probe 10 so that the reflected light from the mineral M to be measured is taken into the optical fiber cable. It is connected.

A ring-shaped light-shielding ring 14 having an opening through which reflected light passes is provided at the tip of the probe 10, and the light-shielding ring 14 is rotatably attached in the circumferential direction. Usually, the reflection spectrum obtained by a spectroscope includes noise called dark current from a photodetector or an electronic circuit that converts light that has passed through the spectroscope into an electric signal. Therefore, in order to measure the reflection spectrum peculiar to the mineral to be measured more accurately, it is necessary to consider the influence of dark current. Therefore, it is preferable to provide the light-shielding ring 14 at the portion where the reflected light of the mineral M to be measured is taken in as in the present embodiment. By rotating the light-shielding ring 14 to block the reflected light as shown in FIG. 4, it is possible to grasp the influence of the dark current when the reflection spectrum is not measured. Although the light-shielding ring 14 is used in the present embodiment, the structure for blocking the reflected light is not particularly limited, and a shutter structure capable of freely opening and closing the path of the reflected light may be provided.

As shown in FIG. 5, the spectroscope main body 20 includes a plurality of spectroscopes 23, a control unit 24, and an output unit 25. Each spectroscope 23 has a different measurable wavelength range. In the present embodiment, the first spectroscope 23a uses the B & W TEK BRC-711E having a measurable wavelength range of 400 to 1000 nm, and the second spectroscope is used. B & W TEK BTC-261P having a measurable wavelength range of 900 to 1700 nm was used as the instrument 23b, and B & W TEK BTC-263 having a measurable wavelength range of 1600 to 2500 nm was used as the third spectroscope 23c. There is. The measurable wavelength range of the spectroscope 23 used, the number of spectroscopes 23, and the like are appropriately changed according to the mineral M to be measured. Further, since the measurement accuracy of the reflection spectrum may decrease in the vicinity of the upper limit and the lower limit of the measurable wavelength range, the measurable wavelength ranges of the plurality of spectroscopes 23 are overlapped with each other as in the present embodiment. It is preferable to select each spectroscope.

As shown in FIG. 6, a plurality of optical fibers 31 are bundled inside the optical fiber cable 30 that connects the probe 10 and the spectroscopic apparatus main body 20. The optical fiber cable 30 connected to the probe 10 is distributed to three optical fiber cables 30a, 30b, 30c inside the spectroscope main body 20, and the distributed optical fiber cables 30a, 30b, 30c are shown in FIG. It is connected to each of the three spectroscopes 23a, 23b, and 23c shown, and on the probe side, its ends are substantially axially symmetrical or randomly arranged. Therefore, the reflection spectra measured by the three spectroscopes 23a, 23b, and 23c are those measured under the same conditions as the position where the light is irradiated to the mineral M to be measured and the position where the reflected light is received.

Depending on the specifications of the spectroscope 23 used, the light sensitivities of the spectroscopes 23a, 23b, and 23c may differ from each other. In this case, as in the present embodiment, a plurality of optical fibers 31 may be provided inside the optical fiber cable 30, and the number of optical fibers 31 may be distributed according to the light sensitivity of each spectroscope 23a, 23b, 23c. preferable. As a result, the spectroscopes 23a, 23b, and 23c can be operated simultaneously with the highest efficiency, which leads to a reduction in measurement time, which is advantageous for portable applications and, for example, the sensitivity of each spectroscope. When adjusting the brightness of the light source according to the above, it is possible to avoid the change in color temperature that occurs in the incandescent bulb, the reflection spectrum can be measured more accurately, and a more realistic spectrum pattern can be obtained. At the same time, it becomes easy to calibrate each spectroscope.

The control unit 24 shown in FIG. 5 is configured to perform a process of joining the reflection spectra acquired by the spectroscopes 23a, 23b, and 23c to each other, and can perform a process of joining the spectra described later. It has a calculation function. The reflection spectra measured by the spectroscopes 23a, 23b, and 23c are joined to one reflection spectrum by the control unit 24, and the information of the reflection spectrum is sent to the output unit 25 as a spectrum pattern of the mineral M to be measured. The output unit 25 is configured to display the spectrum pattern on a display unit (not shown) such as a display provided outside the spectroscopic device 1. The control unit 24 may be provided outside the spectroscopic apparatus main body 20. Further, the display unit may be provided on the spectroscopic apparatus main body 20.

The spectroscopic device 1 according to the present embodiment is configured as described above. By using this spectroscope 1, it is possible to acquire a reflection spectrum in a wide wavelength range by measurement under the same conditions. By the way, when there are three spectroscopes 23, three reflection spectra can be obtained. Therefore, in order to obtain a spectral pattern of the mineral M to be measured, it is necessary to combine those reflection spectra into one.

Hereinafter, an example of a method for joining the reflection spectrum will be described.

For example, it is assumed that two spectroscopes 23 obtain a reflection spectrum as shown in FIG. The "first spectrum" in FIG. 7 is a reflection spectrum obtained by the first spectroscope 23a, and the "second spectrum" is a reflection spectrum obtained by the second spectroscope 23b.

As one of the general spectrum joining processing methods, there is a joining processing method carried out according to the control flow shown in FIG. First, as step S100, as shown in FIG. 9, the upper limit of the wavelength range in which the spectrum is bonded by cutting off the portion affected by the disturbance such as scattering at the upper limit side end of the wavelength range of the first spectrum. Set the value (hereinafter, "junction wavelength upper limit value"). The method of determining the disturbance portion of the reflection spectrum may be the same as the conventional method. For example, the reflection spectrum obtained by each spectroscope is approximated by a three-dimensional curve, and the wavelength range greatly deviated from the approximation is defined as the disturbance portion. There is a way.

Next, as step S110, at the lower end of the wavelength region of the second spectrum, the portion affected by disturbance such as scattering is cut off, and the lower limit of the wavelength region for performing the spectrum junction processing (hereinafter, “” Set the lower limit of wavelength at the junction ").

Finally, as step S120, the weighted average value of the reflectance of the first spectrum and the reflectance of the second spectrum is calculated in the wavelength range within the range of the upper limit value of the junction wavelength and the lower limit value of the junction wavelength. Specifically, at the lower limit of the wavelength of the junction, the weight of the reflectance of the first spectrum and the reflectance of the second spectrum is set to 100: 0, and the reflectance of the first spectrum is the spectrum after the junction processing (hereinafter, Let it be the reflectance of "junction spectrum"). Then, the reflectance of the junction spectrum is calculated so that the influence of the first spectrum becomes smaller and the influence of the second spectrum becomes larger toward the junction wavelength upper limit value from the junction wavelength lower limit value. For example, at a wavelength (about 950 nm) between the lower limit of the wavelength of the junction and the upper and lower values of the wavelength of the junction, the weights of the reflectance of the first spectrum and the reflectance of the second spectrum are set to 50:50, and both reflections are made. Dividing the sum of the rates by 2 gives the reflectance of the junction spectrum. Further, in the upper limit of the wavelength of the junction, the weight of the reflectance of the first spectrum and the reflectance of the second spectrum is set to 0: 100, and the reflectance of the second spectrum is defined as the reflectance of the junction spectrum. By performing such a calculation, the reflection spectra can be smoothly connected.

However, in the case of the above spectrum joining process, if the signal levels of the spectroscopes 23 are different from each other, even if the spectra can be smoothly connected to each other, the joining spectrum is sufficient for the reflection spectrum of the mineral M to be measured. It cannot be said that it is reflected in. In particular, since the spectroscope 1 according to the present embodiment can make the measurement conditions of the reflection spectra in each spectroscope 23 substantially the same, the reflectance of the first spectrum is the reflectance of the second spectrum as shown in FIG. On the other hand, it is presumed that the signal levels of both spectra are different in the state where the overall size is smaller.

Therefore, in the present embodiment, the spectrum joining process is performed according to the control flow shown in FIG.

First, in step S200, the upper limit of the wavelength of the junction is set in the same manner as in step S100 described above. Subsequently, in step S210, the lower limit of the wavelength of the junction is set in the same manner as in step S110 described above.

Next, as step S220, as shown in FIG. 11, the average value of the reflectance of the first spectrum in the wavelength range within the range of the junction wavelength upper limit value and the junction wavelength lower limit value (hereinafter, “first spectrum”. Calculate the average value "). The average value here is a simple average value.

Next, as step S230, the average value of the reflectance of the second spectrum in the wavelength range within the range of the upper limit value of the junction wavelength and the lower limit value of the junction wavelength (hereinafter, “second spectral average value”) is calculated. .. The average value here is a simple average value.

Then, in step S240, as shown in FIG. 12, the first spectrum is offset so as to coincide with the first spectrum mean value and the second spectrum mean value. That is, the reflectance value of the first spectrum is corrected so that the first spectral mean value and the second spectral mean value match and the spectral pattern of the first spectrum does not change.

Finally, as step S250, as shown in FIG. 13, the bonding process of the corrected first spectrum and the second spectrum in the wavelength range within the range of the junction wavelength upper limit value and the junction wavelength lower limit value. I do. The joining treatment method at this time is the same as the method carried out in step S120 shown in FIG. The spectrum joining process according to the present embodiment ends here.

In this way, when the joining process of the first spectrum and the second spectrum is performed, the signal level of the first spectrum is corrected to obtain a more realistic spectral pattern of the mineral M to be measured. Can be done. The joining process of the second spectrum and the reflection spectrum obtained by the third spectroscope 23c is also carried out in the same manner as in steps S200 to S250.

As described above, according to the spectroscope 1 according to the present embodiment, a plurality of spectroscopes 23 are built in the spectroscope main body 20, and the reflected light of the mineral to be measured taken in from the probe 10 is transmitted through the optical fiber cable 30. Since it is distributed to each spectroscope 23, the measurement conditions of the reflection spectrum in each spectroscope 23 can be made substantially the same. Therefore, it is possible to accurately measure the reflection spectrum in a wide wavelength range with one spectroscope. Thereby, the identification accuracy of the mineral can be improved. Further, when acquiring the spectrum pattern, it is not necessary to measure the reflection spectrum many times with a plurality of spectroscopic devices as in the conventional case, so that the working time can be shortened.

Then, the control unit 24 of the spectroscope 1 is configured to join the reflection spectra of each spectroscope 23 by the method shown in steps S200 to S250, thereby obtaining a more realistic mineral spectrum pattern. Can be done. Thereby, the identification accuracy of the mineral can be further improved.

In the present embodiment, the optical fiber 31 is used as the light guide path which is the path of the reflected light, but other members may be used as long as the reflected light can be appropriately sent to the spectroscope 23. Further, the mounting position of the light guide path with respect to the probe 10 and the mounting position of the light source 13 are not limited to those described in the present embodiment. That is, the probe 10 may have a configuration capable of irradiating the measurement target with light by the built-in light source 13 and taking the light reflected by the measurement target into the light guide path connected to the probe 10.

Further, in the spectrum joining processing method of the present embodiment, the first spectrum is moved in step S240, but the second spectrum may be offset toward the first spectrum. Further, the method for joining the spectrum in step S250 is not limited to the method described in this embodiment, and may be another generally known method.

Further, in the present embodiment, the spectroscopic device 1 is operated by an external power source, but for example, a battery may be mounted on the spectroscopic device main body 20 to form a portable spectroscopic device 1. As a result, when visiting the site for mineral exploration, the spectral pattern of the mineral M to be measured can be obtained on the spot. Therefore, the time required to complete the identification of the mineral can be shortened as compared with the case where the collected mineral is brought back and the reflection spectrum is measured.

Although the embodiments of the present invention have been described above, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the technical idea described in the claims, and of course, the technical scope of the present invention also includes them. It is understood that it belongs to.

The present invention can be applied to the identification work of minerals related to metal resource exploration. The object to be identified is not limited to minerals related to metal resource exploration, and may be other materials. For example, in the field of civil engineering, it can be applied to quality control of stone materials including slopes, embankments, constituent minerals of cuts, rocks / minerals collected from the face of a tunnel, and crushed stones. Further, the method for joining the reflection spectra according to the present invention is not limited to the case of joining the reflection spectra measured by a spectroscope having a plurality of spectroscopes, but also a plurality of reflection spectra measured by a conventional spectroscope. It can also be applied when joining.

1 Spectrometer 10 Probe 11 Power cable 12 Trigger button 13 Light source 14 Light-shielding ring 20 Spectrometer body 21 Spectrometer body housing 22 Concave 23 Spectrometer 23a First spectroscope 23b Second spectroscope 23c Third spectroscope 24 Control unit 25 Output unit 30 Optical fiber cable 30a Distributed optical fiber cable 30b Distributed optical fiber cable 30c Distributed optical fiber cable 31 Optical fiber M Measurement target mineral

Claims (7)

A probe that has a built-in light source that irradiates the object to be measured and captures the light reflected by the object to be measured.
A spectroscope body having a plurality of spectroscopes having different measurable wavelength ranges,
A light guide path that connects the probe and the main body of the spectroscope and distributes the reflected light of the measurement object captured from the probe to each spectroscope.
It is equipped with a control unit that performs joining processing of the reflection spectrum acquired by each spectroscope.
The control unit
The disturbance part on the upper limit side of the wavelength range of the first spectrum is cut off to set the upper limit value of the wavelength of the junction.
The disturbance part on the lower limit side of the wavelength range of the second spectrum is cut off to set the lower limit value of the wavelength of the junction.
The average value of the reflectance of the first spectrum is calculated in the wavelength range within the range of the upper limit of the wavelength of the junction and the lower limit of the wavelength of the junction, and the first spectrum average value is set.
The average value of the reflectance of the second spectrum is calculated in the wavelength range within the range of the upper limit of the wavelength of the junction and the lower limit of the wavelength of the junction, and the second spectrum average value is set.
The reflectance value of either one of the first spectrum and the second spectrum is set so that the first spectrum mean value and the second spectrum mean value match, and the spectrum pattern. Correct so that
A spectroscopic apparatus configured to control joining one of the corrected spectra and the other spectrum in a wavelength range within the range of the upper limit of the wavelength of the junction and the lower limit of the wavelength of the junction. The spectroscopic device according to claim 1, wherein the light guide path is formed by bundling a plurality of optical fibers. The spectroscope according to claim 2, wherein the number of the optical fibers connected to each spectroscope differs depending on the sensitivity of each spectroscope. The spectroscopic device according to any one of claims 1 to 3, wherein the probe is provided with a light-shielding shutter that can be opened and closed at a portion where the reflected light of the measurement object is taken in. The spectroscopic device according to any one of claims 1 to 4, wherein the light source is a halogen lamp. The spectroscopic device according to any one of claims 1 to 5, further comprising a battery. It is a method of joining reflection spectra that joins reflection spectra measured by multiple spectroscopes.
The disturbance part on the upper limit side of the wavelength range of the first spectrum is cut off to set the upper limit value of the wavelength of the junction.
The disturbance part on the lower limit side of the wavelength range of the second spectrum is cut off to set the lower limit value of the wavelength of the junction.
The average value of the reflectance of the first spectrum is calculated in the wavelength range within the range of the upper limit of the wavelength of the junction and the lower limit of the wavelength of the junction, and the first spectrum average value is set.
The average value of the reflectance of the second spectrum is calculated in the wavelength range within the range of the upper limit of the wavelength of the junction and the lower limit of the wavelength of the junction, and the second spectrum average value is set.
The reflectance value of either one of the first spectrum and the second spectrum is set so that the first spectrum mean value and the second spectrum mean value match, and the spectrum pattern. Correct so that
A method for joining a reflection spectrum, which joins one of the corrected spectra and the other spectrum in a wavelength range within the range of the upper limit of the wavelength of the junction and the lower limit of the wavelength of the junction.

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