JP2017044495A - Substance detection device, substance detection system, and substance detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a substance that can hardly be recognized by the captured image of visible light in a detection area easily with a fine resolution without requiring excessive user labor.SOLUTION: A laser diode LD1 for gas detection radiates a laser beam LS1 for gas detection that has a wavelength for gas detection to a detection area. A laser diode LD2 for distance measurement radiates a laser beam LS2 for distance measurement to the detection area. A distance calculation unit 272 measures the distance to an irradiated position on the basis of a reflected light RV2 that is the laser beam LS2 reflected at the irradiated position within the detection area. A signal gain adjustment unit 14 adjusts the output gain of the laser beam LS1 for gas detection in accordance with the measured distance. A substance detection processing unit 273 detects the presence of a gas on the basis of a reflected light RV1 at the irradiated position of the laser beam LS1 for gas detection that has had its output gain adjusted. In the scanning of the laser beam LS1 and the laser beam LS2, the irradiated position of the laser beam LS2 precedes the irradiated position of the laser beam LS1 in time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a substance detection device, a substance detection system, and a substance detection method for detecting a substance that is difficult to visually recognize in a detection region by visible light imaging.

  Conventionally, as a prior art for detecting a substance (for example, gas) that is difficult to visually recognize in a detection region, for example, a gas concentration measuring device that emits measurement light from a semiconductor laser toward a measurement atmosphere is known ( For example, see Patent Document 1).

  The gas concentration measuring device of Patent Document 1 emits measurement light frequency-stabilized by a gas absorption line from a semiconductor laser unit to a measurement atmosphere, and reflects reflected measurement light reflected from the measurement atmosphere as the measurement light is emitted. Light is received by the receiver. The gas concentration measuring device detects a fundamental wave phase sensitive detection signal and a double wave phase sensitive detection signal of the modulation frequency of the semiconductor laser from the output signal of the light receiver, and based on the ratio of both signals, the gas concentration of the measurement atmosphere Measure. Further, in the semiconductor laser unit of the gas concentration measuring apparatus, the light receiver is disposed at the back of the central axis in the bottomed cylindrical main body. A semiconductor laser module including a semiconductor laser, a laser pointer that emits visible light as guide light, a measurement light that is arranged on the optical axis of the light receiver and is emitted from the semiconductor laser, and a guide light that is emitted from the laser pointer. A multiplexing / demultiplexing means for synthesizing on substantially the same axis is incorporated in the main body. Thereby, the gas concentration measuring apparatus can confirm the emission position of the measurement light and accurately emit the measurement light toward the measurement position.

JP-A-2005-106521

  In the configuration of Patent Document 1, gas detection targeting an arbitrary point in the measurement atmosphere is assumed, but an arbitrary two-dimensional area (in other words, in the measurement atmosphere starting from the gas concentration measurement device) Gas detection for spatial areas) is not expected.

  For this reason, using the configuration of Patent Document 1, if an arbitrary two-dimensional area is set as a gas detection range, the user can specify the direction of the semiconductor laser module in the gas concentration measurement device (that is, the emission of laser light). It is necessary to manually change the direction and detect the irradiation position of the laser light in the measurement atmosphere one by one. For this reason, when trying to detect the gas existing in the area (detection region), it takes a lot of labor for the work, and it is difficult to detect the gas under the condition that a fine resolution can be obtained.

  The present invention has been made in view of the above-described conventional circumstances, and easily detects a substance that is difficult to visually recognize with visible light imaging within a detection region without requiring a great deal of user effort. Provided are a substance detection device, a substance detection system, and a substance detection method.

  The present invention provides a first light source that emits first light having a wavelength for detecting a substance to a detection area, and a second light source that emits second light having a wavelength for measuring a distance to the detection area; The distance measurement unit that measures the distance to the irradiation position based on the reflected light of the second light reflected by the irradiation position in the detection area, and the measurement result of the distance measurement unit And a gain adjusting unit that adjusts an output gain of the first light, and the first light whose output gain is adjusted by the gain adjusting unit is reflected at the irradiation position. A substance detection unit that detects the presence or absence of the substance in the detection area based on the reflected light of the first and second lights in the detection area. The first light is irradiated at the irradiation position where the first light is irradiated. That is irradiated irradiated with temporally preceding the position, to provide a substance detection apparatus.

  Further, the present invention is a substance detection method in a substance detection apparatus having at least a first light source and a second light source, and emits measurement light having a distance measurement wavelength from the second light source to a detection area. And measuring the distance to the irradiation position based on the reflected light of the measurement light reflected at the irradiation position in the detection area, and depending on the distance to the irradiation position obtained by the measurement The output gain of the detection light having the wavelength for detecting the substance is adjusted, the detection light with the output gain adjusted is emitted from the first light source to the detection area, and the output gain is adjusted. Based on the reflected light of the detection light reflected at the irradiation position, the detection light detects the presence or absence of the substance in the detection area, and in the scanning of the detection light and the measurement light in the detection area, Irradiation position whose serial detection light is irradiated, the measuring light is irradiated with temporally precedes the irradiation position to be irradiated, providing a substance detection method.

  According to the present invention, a substance that is difficult to visually recognize with visible light imaging can be easily detected with a fine resolution in the detection region without requiring much labor of the user.

Explanatory drawing of the outline | summary of the gas detection camera containing the invisible light sensor of this embodiment The figure which shows the example of a scanning of the detection area by the sensor scan unit in a comparative example The figure which shows the example of a scanning of the detection area by the sensor scan unit in this embodiment The figure explaining the irradiation position of the laser beam for gas detection and the laser beam for distance measurement in the range enclosed with the dotted line frame h of FIG. 3 in time series The figure which shows an example of an internal structure of the sensor scan unit of this embodiment The figure which shows the drive example of the collimating lens provided in the sensor scan unit of this embodiment The figure which shows the example of a drive of the collimating lens seen from the upper direction of FIG. 6 (-z direction) In this embodiment, the figure which shows an example of each irradiation position of the turning operation | movement of a sensor scan unit, the laser beam for distance measurement, and the laser beam for gas detection in the case of scanning one line in a forward direction (-y direction) The figure which shows an example of each irradiation position of the turning operation | movement of a sensor scan unit, the laser beam for distance measurement, and the laser beam for gas detection in the case of scanning 1 line in the backward direction (+ y direction) in this embodiment The block diagram which shows an example of an internal structure of the gas detection camera of this embodiment in detail FIG. 10 is a block diagram showing in detail an example of the internal configuration of the light receiving processing unit shown in FIG. (A), (B) The graph which shows an example of the output gain corresponding to the distance registered into the table Timing chart for explaining an example of a distance detection method in the gas detection camera of the present embodiment The figure explaining an example of the input signal and output signal of a laser beam in case the oscillation frequency of a laser diode is the optimal range with respect to the absorption spectrum of a specific substance The figure explaining an example of the input signal and output signal of a laser beam when the oscillation frequency of a laser diode shifts from the oscillation frequency of the optimal range to the low wavelength side with respect to the absorption spectrum of a specific substance The figure explaining an example of the input signal and output signal of a laser beam when the oscillation frequency of a laser diode shifts from the oscillation frequency of the optimal range to the long wavelength side with respect to the absorption spectrum of a specific substance The flowchart explaining an example of the signal processing procedure of the invisible light sensor in a comparative example The flowchart explaining an example of the signal processing procedure of the invisible light sensor in this embodiment (A) a graph showing an example of the relationship between the distance to the gas to be detected and the signal level of the reflected light reflected by the gas when the output gain of the detection light for gas detection is low in the conventional substance detection device; B) A graph showing an example of the relationship between the distance to the gas to be detected and the signal level of the reflected light reflected by the gas when the output gain of the detection light for gas detection is high in the conventional substance detection device, (C ) Graph showing an example of the relationship between the distance to the gas to be detected and the signal level of the reflected light reflected by the gas when the output gain of the laser beam for gas detection is variable in the gas detection camera of this embodiment Figure showing an example of a monitor display screen

(Background to the contents of this embodiment)
First, before describing in detail an embodiment (hereinafter referred to as “this embodiment”) that specifically discloses an embodiment of a substance detection device, a substance detection system, and a substance detection method according to the present invention, The process leading to the contents of the detection camera as an example of the substance detection apparatus will be described with reference to FIGS. 19 (A) and 19 (B). Hereinafter, gas will be described as an example of an object to be detected by the detection camera of the present embodiment, but the substance to be detected is not limited to gas (see below).

  FIG. 19A shows an example of the relationship between the distance to the gas to be detected and the signal level of the reflected light reflected by the gas when the output gain of the detection light for gas detection is low in the conventional substance detection device. It is a graph to show. FIG. 19B shows an example of the relationship between the distance to the gas to be detected and the signal level of the reflected light reflected by the gas when the output gain of the detection light for gas detection is high in the conventional substance detection device. It is a graph to show. In FIG. 19A and FIG. 19B, the reflected light signal is a light reception signal received by a conventional substance detection device.

  The conventional substance detection apparatus including the above-described Patent Document 1 performs gas detection for an arbitrary place in the measurement atmosphere, and any two-dimensional measurement in the measurement atmosphere starting from the substance detection apparatus. Gas detection was not performed for a large area (in other words, a spatial area).

  In addition, as shown in FIG. 19A, when the output gain of the laser beam for substance detection (in other words, the emission intensity of the laser beam emitted from the substance detection device) is low, a short distance from the substance detection device. When the reflected light reflected by the gas present at the position is received by the substance detection device, the level of the light reception signal is high, so that the gas can be detected. However, since the reflected light reflected by the gas located at a long distance from the substance detection device is received by the substance detection device, the level of the light reception signal is low, so it is difficult to detect the gas. .

  On the other hand, as shown in FIG. 19B, when the output gain of the laser beam for substance detection (in other words, the emission intensity of the laser beam emitted from the substance detection device) is high, the substance detection device is far away from the substance detection device. When the reflected light reflected by the gas present at the position is received by the substance detection device, the level of the light reception signal is high, so that the gas can be detected. However, when the reflected light reflected by the gas present at a short distance from the substance detection device is received by the substance detection device, the level of the received light signal becomes too high and becomes saturated, and the gas detection It was difficult. For this reason, in the prior art, the distance range in which a substance such as gas can be detected is limited to a predetermined distance range (for example, 5 m to 10 m) from the substance detection device, for example.

  Therefore, in the present embodiment below, the distance to the gas as an example of the substance to be detected is measured, and the output gain of the laser beam for gas detection is made variable according to the obtained distance, so that the gas An example of a gas detection system including a gas detection camera and a detection camera as an example of a substance detection apparatus that does not require restriction on the detectable distance range will be described.

  Hereinafter, embodiments of a gas detection camera, a gas detection system, and a gas detection method of this embodiment will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

  FIG. 1 is an explanatory diagram of an outline of a gas detection camera 1 including the invisible light sensor NVSS of the present embodiment. A gas detection camera 1 shown in FIG. 1 includes a visible light camera VSC and a non-visible light sensor NVSS.

  The visible light camera VSC uses, for example, reflected light RM, which is visible light having a predetermined wavelength (for example, 0.4 to 0.7 μm), as in the case of an existing monitoring camera, as a detection example as a predetermined detection area. A person HM and an object (not shown) existing in the space K are imaged. Hereinafter, image data obtained by imaging with the visible light camera VSC is referred to as “visible light camera image data”. As described above, the gas detection camera 1 includes both the configuration of the invisible light sensor NVSS that detects invisible light and the visible light camera VSC that obtains visible light camera image data by imaging.

  The non-visible light sensor NVSS optically scans the detection space K that is the same as the visible light camera VSC for the emission of laser light that can be irradiated to a position having a finite area with a predetermined diameter (hereinafter referred to as an irradiation position). Thus, the laser light LS1 that is invisible light (for example, infrared light) having a predetermined wavelength is projected. The projected laser beam LS1 is light having a wavelength in a wavelength band that is easily absorbed by a substance to be detected (also referred to as a specific substance). Specifically, in this embodiment, the wavelength that is easily absorbed by the gas to be detected. It has a band wavelength.

  The non-visible light sensor NVSS is a light reflected by the object to be detected (for example, a gas GS such as methane gas as a specific substance) or a light reflected by the reflecting object in the detection space after passing through the object to be detected. (That is, the reflected light RV1) is received, and whether or not a specific substance (for example, gas) is detected in the detection space K is determined based on the received light intensity of the received reflected light RV1.

  The specific substance for determining the presence or absence of detection by the non-visible light sensor NVSS is, for example, a substance that is difficult to discriminate with visible light camera image data from the visible light camera VSC (in other words, it is difficult for a person to visually recognize an image with an existing monitoring camera). In addition to gas (gas), it may be a transparent liquid such as water or a transparent solid such as ice, and is not particularly limited. As described above, the case where the detection target substance is the gas GS will be exemplified below.

  In addition, the gas detection camera 1 includes output image data (hereinafter referred to as “substance position”) including, in the visible light camera image data captured by the visible light camera VSC, a determination result of whether or not a specific substance detected by the invisible light sensor NVSS is detected. Display data obtained by synthesizing information (substance name, etc.) on the substance position image data).

  The output destination of the display data from the gas detection camera 1 is an external connection device connected to the gas detection camera 1 via a network (not shown), for example, the camera server CS or the monitor 150 shown in FIG. The gas detection system of this embodiment may be configured to include the gas detection camera 1 and the monitor 150, or may be configured to include the gas detection camera 1 and the camera server CS. Here, the network may be a wired network (for example, an intranet or the Internet), or may be a wireless network (for example, a wireless local area network (LAN)).

  FIG. 2 is a diagram illustrating a scanning example of the detection area SARm by the sensor scan unit 5m in the comparative example. The sensor scan unit 5m of the comparative example rotates the pan head (not shown) in the pan direction P and the tilt direction T so as to satisfy the scan angle of view covering the entire detection area SARm starting from the sensor scan unit 5m. Thus, the laser beam LSm emitted from the gas detection laser diode (not shown) mounted on the pan head is emitted while scanning zigzag. Thereby, the sensor scan unit 5m can irradiate the entire region of the detection region SARm with the laser light LSm.

  FIG. 3 is a diagram illustrating a scanning example of the detection area SAR by the sensor scan unit 5 in the present embodiment. The sensor scan unit 5 of this embodiment turns the pan head 10 (see FIG. 5) in the pan direction P and the tilt direction T so as to satisfy the scan angle of view covering the entire detection area SAR starting from the sensor scan unit 5. By driving, the laser beam LS1 from the gas detection laser diode LD1 (see FIG. 5) and the laser beam LS2 from the distance measurement laser diode LD2 (see FIG. 5) mounted on the pan head 10 are zigzag-shaped. The light is emitted while scanning. In the scanning of the present embodiment, the laser beam LS2 for distance measurement is emitted to the same irradiation position before the irradiation position where the laser beam LS1 for gas detection is irradiated (see FIG. 4).

  FIG. 4 is a diagram illustrating the irradiation positions of the laser beam LS1 for gas detection and the laser beam LS2 for distance measurement in a range surrounded by a dotted frame h in FIG. 3 in time series. In FIG. 4, the laser beams LS <b> 1 and LS <b> 2 are emitted toward the right side of the drawing (see “−y direction” shown in FIG. 1). The laser beams LS1 and LS2 are simultaneously irradiated spotwise so that the irradiation positions are adjacent except for the first irradiation position (that is, the irradiation position shown on the leftmost side in FIG. 4). Hereinafter, the operation in which the gas detection camera 1 spot-irradiates the laser beams LS1 and LS2 to the irradiation positions having the same predetermined diameter and a finite area is abbreviated as “spot irradiation”. Therefore, the emission positions of the laser beams LS1 and LS2 reciprocate in the horizontal direction and also move in the vertical direction so that the emission of the laser beams LS1 and LS2 moves in a zigzag manner in a two-dimensional manner in the detection region SAR. Scanned.

  In the first (ie, leftmost) spot irradiation shown in FIG. 4, the laser beam LS2 for distance measurement is irradiated to the irradiation position SP21.

  In the subsequent spot irradiation (that is, in the center), the laser beam LS2 for distance measurement is irradiated to the irradiation position SP22 moved to the right by one irradiation position from the irradiation position SP21 in the first spot irradiation. At this time, the laser beam LS1 for gas detection is irradiated to the same irradiation position SP11 as the irradiation position SP21 in the first spot irradiation of the laser beam LS2 for distance measurement.

  Similarly, in the subsequent (ie, rightmost) spot irradiation, the irradiation position of the laser beam LS2 for distance measurement and the irradiation position of the laser light LS1 for gas detection both move to the right by one irradiation position. That is, the laser beam LS2 for distance measurement is irradiated to the irradiation position SP23 moved to the right by one irradiation position from the irradiation position SP22 in the last spot irradiation. At this time, the laser beam LS1 for gas detection is irradiated to the same irradiation position SP12 as the irradiation position SP22 in the spot irradiation immediately before the laser beam LS2 for distance measurement. Thereafter, similarly, spot irradiation of the laser beams LS1 and LS2 is repeated.

  As described above, in the gas detection camera 1 of the present embodiment, the irradiation position of the laser beam LS2 for distance measurement precedes the irradiation position of the laser beam LS1 for gas detection by one irradiation position. As a result, the gas detection camera 1 uses the reflected light RV2 reflected by the irradiation position of the laser beam LS2 to the next irradiation position that is the same as the irradiation position of the distance measurement laser beam LS2. The distance to the irradiation position can be measured before the light LS1 is spot-irradiated. Therefore, the gas detection camera 1 sets the output gain of the laser beam LS1 for gas detection according to the distance obtained by the measurement, and sets an appropriate emission intensity for determining the presence / absence of gas with high accuracy. The laser beam LS1 can be irradiated.

  FIG. 5 is a diagram illustrating an example of an internal configuration of the sensor scan unit 5 of the present embodiment. FIG. 5 shows an internal configuration related to the sensor scan unit 5 in the gas detection camera 1 when viewed from the upper side of FIG. 1 (that is, in the −z-axis direction).

  The gas detection camera 1 has a box-shaped housing 1z, for example. An opening 1w for the invisible light sensor NVSS is formed on the front surface (that is, in the x-axis direction) of the housing 1z. Note that transparent glass or resin may be fitted in the opening 1w for waterproofing and dustproofing. Further, the condensing lens V31 (see FIG. 10) of the visible light camera VSC is exposed on the front surface of the housing 1z.

  The sensor scan unit 5 is provided inside the housing 1z so as to be supported. The sensor scan unit 5 includes a pan head 10 that can pivot in a pan direction P (direction along the xy plane in the drawing) and a tilt direction T (z-axis direction in the drawing), and a motor mechanism (not shown) that drives the pan head 10. ) Provided with a pan / tilt unit 15 (see FIG. 10).

  The camera platform 10 as an example of the base includes two laser diodes (that is, a laser diode LD1 for gas detection, a laser diode LD2 for distance measurement), two collimating lenses PLZ1, PLZ2, a photodiode PD, and a condenser lens. CLZ is mounted. On the camera platform 10, the distance measuring laser diode LD2 is disposed above the gas detecting laser diode LD1 in the figure (in the negative direction of the y-axis). The pan / tilt unit 15 detects the emission of the laser beams LS1 and LS2 emitted from the gas detection laser diode LD1 and the distance measurement laser diode LD2 by turning the pan head 10 in the pan direction P and the tilt direction T, respectively. Scanning in two dimensions (horizontal scanning and vertical scanning) is possible within the area SAR.

  The laser light LS1 emitted from the gas detection laser diode LD1 passes through the collimator lens PLZ1 and becomes parallel light, and is emitted toward the detection space K. The reflected light RV1 of the laser light LS1 reflected by the gas GS in the detection space K enters through the opening 1w formed in the housing 1z of the gas detection camera 1, is collected by the condenser lens CLZ, and is photo Light is received by the diode PD0.

  Whether or not the gas GS existing in the detection space K is detected is determined from the absorption spectrum as an example of the absorption characteristic of the reflected light RV1 received by the photodiode PD0. The detection region SAR, which is a range in which the laser light LS1 emitted from the gas detection laser diode LD1 can be scanned in the detection space K, is set by the shape of the opening 1w formed in the housing 1z, for example.

  The laser light LS2 emitted from the distance measuring laser diode LD2 passes through the collimator lens PLZ2 and becomes parallel light, and is emitted toward the detection space K. The reflected light RV2 of the laser light LS2 reflected by the gas GS in the detection space K is incident through the opening 1w formed in the housing 1z of the gas detection camera 1 as in the case of the reflected light RV1 of the laser light LS1. Then, the light is condensed by the condenser lens CLZ and received by the photodiode PD0.

  FIG. 6 is a diagram illustrating an example of driving the collimating lenses PLZ1 and PLZ2 provided in the sensor scan unit 5 of the present embodiment. FIG. 7 is a diagram illustrating an example of driving the collimator lenses PLZ1 and PLZ2 as viewed from above in FIG. 6 (in the −z direction). The collimating lenses PLZ1 and PLZ2 are installed on the camera platform 10 so as to be rotatable about a lens rotation axis AX1 (parallel to the z-axis direction). The mechanisms of the drive units of the collimating lenses PLZ1 and PLZ2 are almost the same.

  A pair of coils KL1a and KL1b are attached to both sides of the collimator lens PLZ1 in the y-axis direction. In addition, a pair of magnets Mg1a and Mg1b are placed on the pan head 10 so as to sandwich the coil KL1a in the z-axis direction. Similarly, a pair of magnets Mg1c and Mg1d are placed on the pan head 10 so as to sandwich the coil KL1b in the z-axis direction. Further, as shown in FIG. 7, the pair of magnets Mg1a and Mg1b covers the current path in the y direction on the lower side of the coil KL1a (that is, does not cover the current in the y direction on the upper side in the figure). ) Installed. Similarly, as shown in FIG. 7, the pair of magnets Mg1c and Mg1d covers the current path in the y direction on the upper side of the coil KL1b (that is, does not cover the current in the y direction on the lower side in the figure). Installed).

  When a pair of magnets Mg1a and Mg1b is arranged so that the side of the magnet Mg1a facing the magnet Mg1b is the N pole and the side of the magnet Mg1b facing the magnet Mg1a is the S pole, Magnetic field lines M1a acting in the −z-axis direction are generated. Similarly, when the pair of magnets Mg1c and Mg1d is arranged such that the side of the magnet Mg1c facing the magnet Mg1d is an N pole and the side of the magnet Mg1d facing the magnet Mg1c is an S pole, the pair of magnets Mg1c and Mg1d A magnetic force line M1b acting in the −z-axis direction is generated between them.

  When a current is passed through the coil KL1a in the direction indicated by the arrow D1a (the direction clockwise to the −z axis), the portion of the coil KL1a sandwiched between the pair of magnets Mg1a and Mg1b is subjected to Fleming's law. A force F1a due to electromagnetic induction acts. This force F1a is a force (rotational force) for rotating the collimating lens PLZ1 counterclockwise in FIG. 7 about the lens rotation axis AX1 (z axis). Similarly, when a current is passed through the coil KL1b in the direction indicated by the arrow D1b (the direction clockwise to the −z axis), the portion of the coil KL1b sandwiched between the pair of magnets Mg1c and Mg1d The force F1b due to electromagnetic induction acts in accordance with the above law. Similar to the force F1a, the force F1b is a force (rotational force) that causes the collimator lens PLZ1 to rotate counterclockwise in FIG. 7 about the lens rotation axis AX1 (z axis). The forces F1a and F1b are proportional to the amounts of current supplied to the coils KL1a and KL1b from the two-dimensional unit control unit 12, which will be described later.

  Further, a spring member (not shown) is attached to the collimator lens PLZ1 so as to urge the collimator lens PLZ1 that is rotatable about the lens rotation axis AX1 to return to the initial position. Therefore, the two-dimensional unit controller 12 stops the collimator lens PLZ1 at an arbitrary rotation angle by supplying current to the coils KL1a and KL1b so that the rotational force of the collimator lens PLZ1 cancels the biasing force of the spring member. Can be made. That is, the collimating lens PLZ1 can be inclined by a predetermined angle with respect to the optical axis. The maximum inclination angle of the collimating lens PLZ1 is a marginal angle at which the coil KL1a is not sandwiched between the pair of magnets Mg1a and Mg1b (the coil KL1b is sandwiched between the pair of magnets Mg1c and Mg1d). The collimating lens PLZ2 will be described in the same manner using the reference numerals corresponding to the collimating lens PLZ1.

  A pair of coils KL2a and KL2b are attached to both sides of the collimator lens PLZ2 in the y-axis direction. Further, a pair of magnets Mg2a and Mg2b are placed on the pan head 10 so as to sandwich the coil KL2a in the z-axis direction. Similarly, a pair of magnets Mg2c and Mg2d are placed on the pan head 10 so as to sandwich the coil KL2b in the z-axis direction. Further, as shown in FIG. 7, the pair of magnets Mg2a and Mg2b covers the current path in the y direction on the upper side in the drawing of the coil KL2a (that is, does not cover the current in the y direction on the lower side in the drawing). ) Installed. Similarly, as shown in FIG. 7, the pair of magnets Mg2c, Mg2d covers the current path in the y direction on the lower side of the coil KL2b in the drawing (that is, does not cover the current in the y direction on the upper side in the drawing). Installed).

  When the pair of magnets Mg2a and Mg2b is arranged so that the side of the magnet Mg2a facing the magnet Mg2b is the N pole and the side of the magnet Mg2b facing the magnet Mg2a is the S pole, , Magnetic field lines M2a acting in the −z-axis direction are generated. Similarly, when the pair of magnets Mg2c and Mg2d is arranged so that the side of the magnet Mg2c facing the magnet Mg2d is an N pole and the side of the magnet Mg2d facing the magnet Mg2c is an S pole, the pair of magnets Mg2c and Mg2d A magnetic force line M2b acting in the −z-axis direction is generated between them.

  When a current is passed through the coil KL2a in the direction indicated by the arrow D2a (the direction clockwise to the −z axis), the portion of the coil KL2a sandwiched between the pair of magnets Mg2a and Mg2b is subjected to Fleming's law. A force F2a due to electromagnetic induction acts. This force F2a is a force (rotational force) that attempts to rotate the collimating lens PLZ2 clockwise about the lens rotation axis AX2 (z axis) in FIG. Similarly, when a current is applied to the coil KL2b in the direction indicated by the arrow D2b (the direction clockwise to the −z axis), the portion of the coil KL2b sandwiched between the pair of magnets Mg2c and Mg2d The force F2b due to electromagnetic induction acts in accordance with the above law. Similar to the force F2a, the force F2b is a force (rotational force) for rotating the collimator lens PLZ2 clockwise about the lens rotation axis AX2 (z axis). These forces F2a and F2b are proportional to the amounts of current supplied to the coils KL2a and KL2b from the two-dimensional unit controller 12 described later.

  In addition, a spring member (not shown) is attached to the collimating lens PLZ2 so as to urge the collimating lens PLZ2 that is rotatable about the lens rotation axis AX2 to return to the initial position. Accordingly, the two-dimensional unit control unit 12 stops the collimator lens PLZ2 at an arbitrary rotation angle by supplying current to the coils KL2a and KL2b so that the rotational force of the collimator lens PLZ2 cancels the biasing force of the spring member. Can be made. That is, the collimating lens PLZ2 can be tilted by a predetermined angle with respect to the optical axis. The maximum inclination angle of the collimating lens PLZ2 is a marginal angle at which the coil KL2a is not sandwiched between the pair of magnets Mg2a and Mg2b (the coil KL2b is sandwiched between the pair of magnets Mg2c and Mg2d).

  As described above, the two-dimensional unit control unit 12 rotates the collimator lenses PLZ1 and PLZ2 to a predetermined rotation angle and tilts the collimator lenses PLZ1 and PLZ2 with respect to the optical axis, whereby the laser beams LS1 and LS1 emitted from the laser diodes LD1 and LD2, respectively. Adjust the pan direction angle of LS2. As a result, the two-dimensional unit control unit 12 determines the irradiation position of the laser light LS1 that is spot-irradiated through the collimating lens PLZ1 and the irradiation position of the laser light LS2 that is spot-irradiated through the collimating lens PLZ2. It can be shifted by one irradiation position. In the present embodiment, both of the collimating lenses PLZ1 and PLZ2 have a rotatable drive unit, but either one may be fixed and only the other may have a drive unit.

  FIG. 8 shows the turning positions of the sensor scan unit 5 when scanning one line in the forward direction (−y direction), the irradiation positions of the laser light LS2 for distance measurement, and the laser light LS1 for gas detection in this embodiment. It is a figure which shows an example. Here, when looking from the top toward the −z-axis direction so as to overlook the paper surface of FIG. 8, the direction in which the camera platform 10 is rotated in the clockwise direction is the plus (+) direction, and the direction in which the head 10 is rotated in the counterclockwise direction is minus. (−) Direction.

  On the camera platform 10, the distance measuring laser diode LD2 is arranged on the upper side (−y-axis direction) in the figure from the gas detecting laser diode LD1, and therefore, the gas detecting laser light LS1 and the distance measuring laser in the forward direction. When scanning the light LS2, the irradiation position SP2 of the distance measurement laser light LS2 precedes the irradiation position SP1 of the gas detection laser light LS1 by one irradiation position without crossing the laser beams. .

  In this case, in order to accurately match the irradiation position SP1 of the gas detection laser beam LS1 irradiated later with the irradiation position SP2 of the distance measurement laser beam LS2 irradiated earlier, the gas detection collimating lens PLZ1 and You may make it adjust by inclining at least one of the collimating lens PLZ2 for distance measurement.

  FIG. 9 shows the turning positions of the sensor scan unit 5 when scanning one line in the return direction (+ y direction), distance measurement laser light LS2 and gas detection laser light LS1 in this embodiment. It is a figure which shows an example. On the camera platform 10, the distance measuring laser diode LD2 is disposed above the gas detecting laser diode LD1 in the figure (in the -y-axis direction), so that the gas detecting laser light LS1 and the distance measuring laser are used in the backward direction. When the laser beam LS2 is scanned, it is necessary to cross the laser beams. At least one of the collimator lens PLZ2 and the collimator lens PLZ2 is greatly inclined, and the irradiation position SP2 of the laser beam LS2 for distance measurement is detected by the gas. The irradiation position SP1 of the laser beam LS1 is preceded by one irradiation position. At this time, in order to accurately match the irradiation position SP1 of the laser beam LS1 for gas detection to be irradiated later with the irradiation position SP2 of the laser beam LS2 for distance measurement irradiated earlier, it may be adjusted simultaneously. .

  In this embodiment, the case where line scanning is performed in the reciprocating direction with the laser beam LS2 for distance measurement and the laser beam LS1 for gas detection has been described. The laser beams LS1 and LS2 may remain crossed or parallel. In this case, the sensor scan unit 5 stops the emission of the respective laser beams LS1 and LS2 at the stage where both the distance measurement and gas detection laser beams LS1 and LS2 have reached the end point in one direction, and immediately It is also possible to move to the start point of the line, start the emission of laser light again, and perform the next line scan. It is also possible to move to the start point of the next line while emitting the laser beam without stopping / resuming the laser beam.

  FIG. 10 is a block diagram showing in detail an example of the internal configuration of the gas detection camera 1 of the present embodiment. As described above, the gas detection camera 1 includes the non-visible light sensor NVSS and the visible light camera VSC. The invisible light sensor NVSS includes a control unit 11, a projection unit PJ, and a light reception processing unit SA. In order to simplify the drawing, in FIG. 10, the gas detection laser diode LD1 and the distance measurement laser diode LD2 are abbreviated as “gas detection LD” and “distance measurement LD”, respectively. The reference numerals “LD1” and “LD2” are different from “LD”.

  The control unit 11 is configured using, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or a DSP (Digital Signal Processor), and for example, totally controls the operation control of each unit of the invisible light sensor NVSS. Signal processing, data input / output processing between other units, data calculation processing, and data storage processing are performed.

  The control unit 11 includes a two-dimensional unit control unit 12, a modulation signal generation unit 13, and a signal gain adjustment unit 14. The two-dimensional unit control unit 12 outputs a pan / tilt drive signal for driving the sensor scan unit 5 in the pan direction P and the tilt direction T to the pan / tilt unit 15. The pan / tilt unit 15 rotates the pan / tilt head 10 in the pan direction and the tilt direction according to the pan / tilt drive signal.

  Further, as described with reference to FIGS. 6 and 7, the two-dimensional unit control unit 12 transmits the collimating lens PLZ1 and the irradiation position of the laser light LS1 that is spot-irradiated and the collimating lens PLZ2. After controlling the amount of current supplied to the coils KL1a, KL1b, KL2a, KL2b in the sensor scan unit 5 so as to shift the irradiation position of the laser beam LS2 irradiated with the spot by one irradiation position, a current is supplied to each coil. Supply.

  The modulation signal generator 13 generates a modulation signal for wavelength-modulating the laser beam LS1 emitted from the gas detection laser diode LD1, and supplies the modulation signal generation unit 13 to the gas detection laser diode LD1 and the distance measurement laser diode LD2 as light source emission signals. Output. The laser diode LD1 for gas detection and the laser diode LD2 for distance measurement emit laser light LS1 and LS2 that have been wavelength-modulated according to the light source emission signal. The modulation signal generation unit 13 may output a signal for emitting laser light LS2 having a constant amplitude and not wavelength-modulated as a light source emission signal input to the distance measuring laser diode LD2. In this case, the distance measuring laser diode LD2 emits a laser beam LS2 having a constant amplitude in accordance with the light source emission signal from the modulation signal generation unit 13.

  Various methods can be used for wavelength modulation. In the present embodiment, wavelength modulation is performed by changing the drive currents of the gas detection laser diode LD1 and the distance measurement laser diode LD2. The drive current is an input signal to each laser diode, and the frequency of the drive current is the frequency modulation frequency. It is also possible to perform wavelength modulation by sweeping (changing) the temperature with a predetermined amplitude with respect to the target temperature for stabilizing each laser diode. In this case, the Peltier element provided in the laser diode absorbs heat or generates heat in accordance with a signal from the control unit 11, so that the temperature of the laser diode can be varied and the wavelength of the laser light can be changed.

  Further, it is desirable that the output gain of the distance measuring laser diode LD2 is set high so that the laser light LS2 reaches a far irradiation position in the detection region SAR. Further, the modulation signal generation unit 13 sets a detection threshold M for detecting a specific substance that is a detection target of the invisible light sensor NVSS in the detection processing unit 27.

  The signal gain adjusting unit 14 as an example of the gain adjusting unit includes a table 14z in which a correspondence relationship between the distance from the gas detection camera 1 and the output gain of the laser light LS1 emitted from the gas detection laser diode LD1 is registered. The signal gain adjustment unit 14 calculates an output gain corresponding to the distance to the irradiation position in the detection region SAR calculated by the distance calculation unit 272 (see FIG. 11) based on the table 14z.

  In addition, the signal gain adjustment unit 14 includes a memory 14y that temporarily stores the calculated output gain. The signal gain adjustment unit 14 sets the output gain stored in the memory 14y to the gas detection laser diode LD1, and adjusts the output gain of the laser light LS1 emitted from the gas detection laser diode LD1 to an optimum value.

  FIGS. 12A and 12B are graphs showing an example of the output gain corresponding to the distance registered in the table 14z. FIG. 12A shows a graph in which the relationship between the distance and the output gain is expressed by a linear function. FIG. 12B shows a graph in which the relationship between the distance and the output gain is expressed by a quadratic function. In both graphs of FIGS. 12A and 12B, the output gain is set to a larger value as the distance becomes longer. These graphs may be set in advance as a function or may be obtained experimentally.

  In addition, the control unit 11 outputs a timing signal for instructing execution of AD conversion in the AD conversion circuit 271 of the detection processing unit 27 described later to the AD conversion circuit 271 in the detection processing unit 27 described later.

  The projection unit PJ includes a gas detection laser diode LD1 as an example of a first light source, a distance measurement laser diode LD2 as an example of a second light source, a gas detection projection light source optical unit OP1, and a distance measurement A projection light source optical unit OP2 and a pan / tilt unit 15 are provided. The gas detection projection light source optical unit OP1 includes a collimator lens PLZ1 and a pair of coils KL1a and KL1b. The distance measurement projection light source optical unit OP2 includes a collimator lens PLZ2 and a pair of coils KL2a and KL2b.

The gas detection laser diode LD1 emits laser light LS1 as an example of detection light that is wavelength-modulated so that the wavelength of the laser light is included in the absorption wavelength band of the gas GS that is the substance to be detected. Here, as a gas is a substance of the detection object, given as an example methane gas (CH _4). The distance measuring laser diode LD2 emits laser light LS2 as an example of wavelength-modulated measuring light, like the gas detecting laser diode LD1.

  The collimating lenses PLZ1 and PLZ2 convert the laser beams LS1 and LS2 emitted from the laser diodes LD1 and LD2 into parallel beams, respectively. As described above, the pair of coils KL1a and KL1b and the pair of coils KL2a and KL2b drive the collimator lens PLZ1 and the collimator lens PLZ2 so as to be inclined by a predetermined angle with respect to the optical axis, respectively.

  The pan / tilt unit 15 pans and tilts the camera platform 10 on which the laser diodes LD1 and LD2, the gas detection projection light source optical unit OP1, the distance measurement projection light source optical unit OP2, the condenser lens CLZ, and the photodiode PD are mounted. Rotate in direction T. That is, the pan / tilt unit 15 is configured to scan the laser beams LS1 and LS2 emitted from the gas detection laser diode LD1 and the distance measurement laser diode LD2 two-dimensionally within a scanning range including the detection region SAR. 10 is turned.

  The light receiving processing unit SA includes a light receiving unit RP that receives the reflected lights RV1 and RV2 reflected in the detection area SAR, and a signal processing unit DS that processes signals of the received laser beams LS1 and LS2. FIG. 11 is a block diagram showing in detail an example of the internal configuration of the light reception processing unit SA shown in FIG. The light receiving unit RP includes a condenser lens CLZ and a photodiode PD0. The signal processing unit DS includes a signal processing unit 26, a detection processing unit 27, and a display processing unit 28.

  The signal processing unit 26 includes an I / V conversion circuit 261, an amplification circuit 262, and a filter processing circuit 263. The detection processing unit 27 includes an AD conversion circuit 271, a distance calculation unit 272, and a substance detection processing unit 273. The functions of the distance calculation unit 272, the substance detection processing unit 273, and the display processing unit 28 are realized by the processor executing a program held in a memory (not shown).

  The condensing lens CLZ condenses the laser light emitted from the gas detection laser diode LD1 and the distance measurement laser diode LD2 and reflected by the specific substance in the detection region SAR, and causes the photodiode PD0 to receive the laser light. The photodiode PD0 generates a charge corresponding to the amount of received laser light and outputs it as a current signal.

  The I / V conversion circuit 261 converts the current signal output from the photodiode PD0 into a voltage signal. The amplifier circuit 262 amplifies the voltage signal output from the I / V conversion circuit 261. The filter processing circuit 263 performs a filter process on the signal amplified by the amplifier circuit 262 and outputs the signal after the filter process to the AD conversion circuit 271 in the detection processing unit 27 as a signal used for substance detection.

  The AD conversion circuit 271 in the detection processing unit 27 converts the signal input from the signal processing unit 26 into a digital signal according to the timing signal output from the control unit 11.

  The signal output from the AD conversion circuit 271 is a signal having a frequency (2f) twice that of the wavelength-modulated laser light signal (frequency 1f) emitted from the gas detection laser diode LD1. A signal having the doubled frequency (frequency 2f) is extracted after being converted into a digital value by the AD conversion circuit 271. In other words, when the laser beam LS1 having the frequency 1f is emitted from the gas detection laser diode LD1, the reflected light RV1 reflected by the gas GS or reflected by the background after passing through the gas GS is reflected by the AD conversion circuit 271. As an output, reflected light having a frequency of 2f is obtained.

  Further, this signal indicates that the temperature of the gas detection laser diode LD1 is not changed, and the modulation wavelength width of the laser light LS1 emitted from the gas detection laser diode LD1 is not shifted from the absorption wavelength band of the specific substance. This is a sine wave signal with a constant frequency obtained based on the signal from the photodiode PD0 (see FIG. 14).

  The distance calculation unit 272 as an example of the distance measurement unit is an irradiation position from the gas detection camera 1 based on the output of the AD conversion circuit 271 corresponding to the reflected light RV2 of the laser light LS2 emitted from the distance measurement laser diode LD2. And a signal representing the calculated distance (distance signal) is output to the control unit 11.

  FIG. 13 is a timing chart for explaining an example of a distance detection method in the gas detection camera 1 of the present embodiment. This represents a change over time in the received light intensity of the laser beam LS2 for distance measurement and the reflected light RV2. Specifically, the distance calculation unit 272 determines that the input of the light source emission signal from the control unit 11 is the time of projection of the laser light LS2 from the distance measurement laser diode LD2 (timing t1 in the drawing). The distance calculation unit 272 receives the reflected light RV2 of the laser light LS2 by the photodiode PD0 in the light reception processing unit SA, and inputs an output from a comparator / peak hold processing unit (not shown) in the amplification circuit 262. Is determined when the reflected light RM is received (timing t2 in the figure). The distance calculation unit 272 can easily derive the distance from the invisible light sensor NVSS to the specific substance, for example, by calculating the distance as “distance = light velocity × (time difference Δt / 2)”.

  The substance detection processing unit 273 as an example of the substance detection unit detects whether or not a specific substance is detected based on the output of the AD conversion circuit 271 corresponding to the reflected light RV1 of the laser beam LS1 emitted from the gas detection laser diode LD1. And a signal representing the detected specific substance is output to the display processing unit 28.

  The display processing unit 28 as an example of the image generation unit is a substance position image indicating a two-dimensional position of the specific substance in the detection region SAR viewed from the invisible light sensor NVSS based on a signal representing the detected specific substance. Generate data. The substance position image data includes image data representing a specific substance and two-dimensional position information (for example, pan angle and tilt angle of the camera platform 10) in the detection area SAR. The display processing unit 28 outputs the substance position image data to the display control unit 37 of the visible light camera VSC.

  In this embodiment, instead of transmitting the substance position image data to the display control unit 37 in the visible light camera VSC, the display processing unit 28, for example, a monitor 150, a camera server CS, or a communication terminal (not shown) described later. ) May be sent directly.

  In this way, display data in which information on the specific substance obtained by the detection processing unit 27 is combined with the visible light image data in the detection region SAR is output. Therefore, the non-visible light sensor NVSS can clearly show to the user where the specific substance is present in the detection region SAR.

  As illustrated in FIG. 10, the visible light camera VSC includes a condenser lens V31, an image sensor V33, a signal processing unit V35, a display control unit 37, and an output unit 38. Each function of the signal processing unit V35 and the display control unit 37 is realized by the processor V20 executing a program held in a memory (not shown).

  The condensing lens V31 collects incident light (reflected light RM) from the outside including the detection area SAR by the invisible light sensor NVSS and forms an image on the imaging surface of the image sensor V33.

  The image sensor V33 is an image sensor having a spectral sensitivity peak with respect to the wavelength of visible light (for example, 0.4 μm to 0.7 μm). The image sensor V33 converts an optical image formed on the imaging surface into an electric signal. The output of the image sensor V33 is input to the signal processing unit V35 as an electrical signal.

  The signal processing unit V35 generates visible light image data defined by, for example, RGB (Red Green Blue) or YUV (luminance / color difference) using an electrical signal that is an output of the image sensor V33. Thereby, visible light image data imaged by the visible light camera VSC is formed. The signal processing unit V35 outputs visible light image data to the display control unit 37.

  For example, when a specific substance is detected at a predetermined position in the visible light image data, the display control unit 37 displays the visible light image data output from the signal processing unit V35 and the substance position output from the display processing unit 28. The display data is generated by combining the image data. This display data is an example of information regarding a specific substance.

  The output unit 38 as an example of the image output unit outputs the display data to an external device (for example, the camera server CS and the monitor 150).

  The camera server CS transmits display data output from the display control unit 37 to a communication terminal or one or more externally connected devices (not shown), and display data on a display screen of the communication terminal or one or more externally connected devices. Prompt display. The monitor 150 displays the display data output from the display control unit 37.

  FIG. 14 is a diagram for explaining an example of an input signal and an output signal of laser light when the oscillation frequency of the laser diode is in the optimum range with respect to the absorption spectrum of the specific substance. FIG. 14 shows an output signal of the laser beam reflected from the specific substance and received by the photodiode with respect to the input signal of the laser beam emitted from the laser diode and subjected to wavelength modulation.

Here, methane gas (CH ₄ ) is taken as an example as a gas that is a substance to be detected. In FIG. 14, the vertical axis represents the received light voltage (unit is a normalized value) corresponding to the output of the I / V conversion circuit 261 corresponding to the reflected light received by the photodiode PD, and the horizontal axis represents the photodiode. It represents the wavelength (nm) of the received laser beam. The portion where the received light voltage is remarkably lowered is an energy absorption region unique to the specific substance, that is, a wavelength band where the absorption rate of the laser beam is high.

  In FIG. 14, the absorption spectrum of the specific substance has a wavelength band centered on 1653.67 nm. On the other hand, the laser light emitted from the laser diode LD1 is modulated with a modulation width of 0.05 nm with a center wavelength of 1653.67 nm as shown in the wavelength modulation range WAR0.

  As described above, the reflected light emitted from the laser diode LD1 and reflected by the specific substance in the detection region SAR or reflected by the background after passing through the specific substance has a certain frequency (1f). It is detected as an output signal having a frequency (2f) twice as large as the input signal of the laser light wavelength-modulated as a sine wave and having a constant amplitude.

  FIG. 15 is a diagram for explaining an example of an input signal and an output signal of laser light when the oscillation frequency of the gas detection laser diode LD1 is shifted from the oscillation frequency in the optimum range to the lower wavelength side with respect to the absorption spectrum of the specific substance. It is. In FIG. 15, as shown in the wavelength modulation range WAR1, the laser light LS1 is wavelength-modulated with, for example, 1653.66 nm as a center wavelength and a modulation width of 0.05 nm. The reflected light in this case is detected as an output signal having a double frequency (2f) and an amplitude that is not constant.

  FIG. 16 is a diagram illustrating an example of an input signal and an output signal of laser light when the oscillation frequency of the gas detection laser diode LD1 is shifted from the oscillation frequency in the optimum range to the long wavelength side with respect to the absorption spectrum of the specific substance. It is. In FIG. 16, as shown in the wavelength modulation range WAR2, the laser beam LS1 is wavelength-modulated with, for example, 1653.68 nm as a center wavelength and a modulation width of 0.05 nm. The reflected light in this case is detected as an output signal having a double frequency (2f) and an amplitude that is not constant.

  As shown in FIGS. 15 and 16, when the wavelength of the laser light emitted from the laser diode LD1 is shifted to the low wavelength side or the long wavelength side, a signal whose amplitude varies is output. This fluctuation in amplitude appears as a state where the wavelength of the laser beam LS1 is shifted from the center wavelength of the energy absorption region of the specific substance. The wavelength of the laser light LS1 depends on the temperature of the laser diode LD1, and if the laser light LS1 deviates greatly due to a temperature change, an output signal having a frequency (2f) twice that of the laser light input signal is not output. That is, it becomes difficult to detect a specific substance. For this reason, temperature control is performed to keep the temperature of the laser diode LD1 constant so that the amplitude of the output signal having a frequency (2f) twice as high as the input signal of the laser light LS1 is constant. preferable. As a result, the gas detection camera 1 can detect an output signal having a frequency (2f) whose amplitude is twice as stable as the input signal of the laser beam LS1, and the accuracy of substance detection is improved.

  Operation | movement of the gas detection camera 1 which has the said structure is shown.

  First, signal processing of the invisible light sensor in the comparative example is shown. In the comparative example, a case where laser light is simply two-dimensionally scanned in the detection region SARm is shown. FIG. 17 is a flowchart for explaining an example of a signal processing procedure of the invisible light sensor in the comparative example. In FIG. 17, when a laser beam is emitted from the gas detection laser diode to the irradiation position in the detection area SARm (S101), if there is a specific substance at the irradiation position in the detection area SARm, The reflected light reflected by a certain gas GS is received by the photodiode PD0. When the output signal from the photodiode PD0 is subjected to various signal processing including amplification processing by the light receiving processing unit SA (S102), the presence or absence of the gas GS as the specific substance is detected (S103).

  Thereafter, it is determined whether or not the substance detection is continued (S104). When the substance detection is continued, the sensor scan unit 5m moves to the next irradiation position (S105). Then, the processing from step S101 is repeated. On the other hand, when the substance detection is not continued, the signal processing of the invisible light sensor is ended as it is.

  FIG. 18 is a flowchart for explaining an example of a signal processing procedure of the invisible light sensor NVSS in the present embodiment. In FIG. 18, the modulation signal generation unit 13 in the control unit 11 outputs a light source emission signal to the distance measuring laser diode LD2, and emits the laser light LS2 toward the irradiation position in the detection region SAR (S1). ). When the photodiode PD0 receives the reflected light RV2 reflected by the laser light LS2 at the irradiation position in the detection region SAR, the distance calculation unit 272 in the light reception processing unit SA receives the irradiation position in the detection region SAR from the sensor scan unit 5. The distance information is acquired by calculating the distance to (S2).

  When the signal gain adjustment unit 14 in the control unit 11 receives the distance information from the distance calculation unit 272, the signal gain adjustment unit 14 acquires an output gain corresponding to the distance calculated in step S3 based on the table 14z (S3). In order to use it as the output gain of the laser beam LS1 for gas detection, it is temporarily stored in the memory 14y (S4).

  The controller 11 determines whether or not the irradiation position of the laser light LS2 emitted from the distance measuring laser diode LD2 is the first irradiation position (S5). When it is the first irradiation position (S5, YES), the two-dimensional unit control unit 12 in the control unit 11 moves the sensor scan unit 5 so that the laser beams LS1 and LS2 can be irradiated to the next irradiation position. (S6). Thereafter, the control unit 11 performs the process of step S1 and repeats the same process.

  On the other hand, when the irradiation position of the laser beam LS2 emitted from the distance measuring laser diode LD2 is not the first irradiation position (S5, NO), the signal gain adjustment unit 14 stores the distance stored in the memory 14y based on the table 14z. An output gain corresponding to the information is acquired, and this output gain is set in the gas detection laser diode LD1 (S7).

  Here, the relationship between the output gain and the received light signal level will be considered. FIG. 19A to FIG. 19C are graphs showing changes in the received light signal level according to distance. FIG. 19A shows the transition of the received light signal level when the output gain is set low. In this case, if the distance to the irradiation position is a short distance, the photodiode obtains a signal with a high light reception level, but at a long distance, the amount of laser light from the laser diode decreases, and the light reception level at which gas detection is possible. I can't get a signal.

  FIG. 19B shows the transition of the received light signal level when the output gain is set high. In this case, even if the distance to the irradiation position is long, the photodiode can obtain a light reception level signal capable of detecting gas, but at a short distance, the light reception level signal is saturated and a high light reception level signal is obtained. I can't.

  On the other hand, in this embodiment, as shown in FIG. 19C, an appropriate output gain corresponding to the distance to the irradiation position is set. FIG. 19C shows the distance to the gas GS to be detected and the reflected light RV1 reflected by the gas GS when the output gain of the laser light LS1 for gas detection is variable in the gas detection camera 1 of the present embodiment. It is a graph which shows an example of the relationship with the signal level. That is, the output gain is set so that the signal level received by the photodiode PD0 falls within a certain level within the range from the short distance to the long distance. The output gain of the laser beam LS1 emitted from the gas detection laser diode LD1 is set to an appropriate value corresponding to the distance to the irradiation position set in the table 14z, so that the photodiode PD0 Even if the irradiation position in the SAR is within a range from a short distance to a long distance, a signal having a substantially constant light reception level can be obtained. The output gain of the distance measuring laser diode LD2 is a relatively large value as described above, and may be a constant value.

  The modulation signal generation unit 13 spot-irradiates the laser beam LS1 for gas detection from the gas detection laser diode LD1 to the irradiation position irradiated with the laser beam LS2 from the distance measurement laser diode LD2 in the previous spot irradiation. (S8). That is, the laser beam LS1 for gas detection is spot-irradiated with a delay of one irradiation position from the laser beam LS2 for distance measurement. At this time, simultaneously with spot irradiation of the laser beam LS1 for gas detection, the modulation signal generation unit 13 spot-irradiates the laser beam LS2 for distance measurement from the laser diode LD2 for distance measurement. That is, the laser beam LS2 for distance measurement is spot-irradiated by one irradiation position ahead of the laser beam LS1 for gas detection.

  The light reception processing unit SA performs various signal processing including amplification processing on the output signal from the photodiode PD0 (S9). The substance detection processing unit 273 detects the presence / absence of the gas GS as the specific substance based on the presence / absence of the output signal having the double frequency (2f) described above as a result of the various signal processing (S10).

  Thereafter, the control unit 11 determines whether or not to continue substance detection (S11). When the substance detection is continued, in step S6, the two-dimensional unit control unit 12 in the control unit 11 moves the sensor scan unit 5 so that the laser beams LS1 and LS2 can be irradiated to the next irradiation position. Thereafter, the control unit 11 returns to the process of step S1 and repeats the same process. On the other hand, when the substance detection is not continued, the control unit 11 ends the signal processing of the invisible light sensor NVSS.

  When the gas GS that is the specific substance is detected in step S10, as described above, the display processing unit 28 generates an image (substance position image data) including the gas GS that is the specific substance. The generated image containing the gas GS as the specific substance is superimposed on the visible light image captured by the visible light camera VSC by the display control unit 37. A composite image obtained by superimposing an image containing the gas GS as the specific substance on the visible light image is displayed on the monitor 150.

  FIG. 20 is a diagram illustrating a display screen example of the monitor 150. The monitor 150 superimposes and displays an image including the gas GS that is a specific substance detected by the invisible light sensor NVSS on a visible light image (an image including the person HM) captured by the visible light camera VSC. Thereby, the user can visually confirm the gas GS displayed on the monitor 150.

  Thus, the gas detection camera 1 of this embodiment, the gas detection laser diode LD1 emits a laser beam LS1 having a wavelength for gas detection in the detection area (sensing area SAR). The distance measuring laser diode LD2 emits a distance measuring laser beam LS2 to the detection region SAR. The distance calculation unit 272 measures the distance to the irradiation position based on the laser beam RV2 reflected at the irradiation position in the detection region SAR. Signal gain adjustment unit 14, in accordance with the distance measured by the distance calculating unit 272 adjusts the output gain of the laser beam LS1 for gas detection. Substance detection processing unit 273, the output gain is adjusted, based on the reflected light RV1 from the irradiation position of the laser beam LS1 for gas detection, it detects the presence of gas. When the gas detection camera 1 scans the laser light LS1 and the laser light LS2 within the detection region SAR, the gas detection camera 1 precedes the laser light LS1.

  Thereby, the gas detection camera 1 can detect a gas (substance) easily in a two-dimensional detection area (detection area SAR). Further, since the output gain of the laser beam LS1 for gas detection is adjusted according to the distance to the irradiation position, the gas detection camera 1 can detect a gas from a short distance to a far distance, and the gas is detected in the detection area SAR. The detectable area can be expanded.

  Further, in the gas detection camera 1, since the laser beam LS1 for gas detection is spot-irradiated at the irradiation position where the laser beam LS2 for distance measurement is previously spot-irradiated, the gas detection camera 1 is used for gas detection. The output gain of the laser beam LS1 can be set to an appropriate value according to the distance. Therefore, the gas detection camera 1 can improve the accuracy of gas detection. Further, distance measurement and gas detection can be performed continuously, and efficient gas detection becomes possible.

  In addition, the gas detection camera 1 rotates the camera platform 10 to which the gas detection laser diode LD1 and the distance measurement laser diode LD2 are fixed, so that the gas detection laser beam LS1 and the distance measurement laser beam LS2 are rotated. Is scanned in the pan direction P and the tilt direction T, the control of scanning the laser beam is simplified and made efficient.

  Further, since the gas detection laser diode LD1 and the distance measurement laser diode LD2 are fixed to the camera platform 10 so that spot irradiation is performed with a shift by one irradiation position, the gas detection laser light LS1 and distance measurement are performed. The control of spot irradiation with the laser beam LS2 shifted by one irradiation position is simplified.

  When the laser beam LS1 for gas detection and the laser beam LS2 for distance measurement are scanned back and forth in the pan direction P, the laser beam for distance measurement is first used in both the forward direction and the backward direction. Since the laser beam LS1 for gas detection is spot-irradiated at the irradiation position where the LS2 is spot-irradiated, the output gain of the laser beam LS1 for gas detection is set to an appropriate value according to the distance in any direction. Can do. Further, the gas detection time can be shortened by reciprocating the gas detection.

  Further, since the gas detection camera 1 generates and outputs an image of the detected gas, the detected gas can be visualized.

  In addition, since the gas image is superimposed on the captured visible light image and displayed on the monitor 150, the user visually recognizes where the gas is on the visible light image by looking at the screen of the monitor 150. it can.

  While the embodiments have been described with reference to the drawings, it is needless to say that the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above-described embodiment, the laser beam LS1 for gas detection and the laser beam LS2 for distance measurement are spot-irradiated with a shift by one irradiation position, but the laser beam LS1 for gas detection is a laser for distance measurement. As long as the light LS2 is spot-irradiated later, the spot irradiating position may be shifted by two or more irradiation positions. Further, not limited to the case of scanning the laser beam LS2 for the laser light LS1 and distance measurement for gas detection and spot irradiation may be scanned with continuous irradiation.

  In the above embodiment, as an example of a specific substance, has been given the methane (CH4), a gas, liquid, solid regardless of, and may be other materials. Table 1, and the specific substance invisible light sensor NVSS can detect, and the wavelength used to detect specific substances are shown. Thereby, the non-visible light sensor NVSS can detect many kinds of specific substances using wavelengths corresponding to individual specific substances, and can generate substance position image data indicating that each specific substance has been detected. it can.

  The present invention provides a substance detection apparatus, a substance detection system, and a substance detection method for easily detecting a substance that is difficult to visually recognize with visible light imaging within a detection area with a fine resolution without requiring much labor of a user. Useful.

DESCRIPTION OF SYMBOLS 1 Gas detection camera 1w Opening part 1z Case 5,5m Sensor scan unit 10 Pan head 11 Control part 12 Two-dimensional unit control part 13 Modulation signal generation part 14 Signal gain adjustment part 14y Memory 14z Table 15 Pan tilt unit 26 Signal processing part 27 Detection processing unit 28 Display processing unit 37 Display control unit 38 Output unit 150 Monitor 261 I / V conversion circuit 262 Amplification circuit 263 Filter processing circuit 271 AD conversion circuit 272 Distance calculation unit 273 Substance detection processing unit AX1, AX2 Lens rotation axis CLZ , V31 condenser lens CS camera server D1a, D1b, D2a, D2b arrow DS signal processing unit F1a, F1b, F2a, F2b force GS gas HM person K detection space KL1a, KL1b, KL2a, KL2b coil LD1, LD2 laser Aode LS1, LS2, RV1, RV2 Laser light SP1, SP2, SP11, SP12, SP21, SP22, SP23 Irradiation position Mg1a, Mg1b, Mg1c, Mg1d, Mg2a, Mg2b, Mg2c, Mg2d Magnet NVSS Invisible light sensor OP1 For gas detection Projection light source optical unit OP2 Projection light source optical unit for distance measurement PD0 Photodiode PJ Projection unit PLZ1, PLZ2 Collimate lens RM Reflected light RP Light reception unit SA Light reception processing unit SAR, SARm Detection region V20 Processor V33 Image sensor V35 Signal processing unit VSC Visible light Camera WAR0, WAR1, WAR2 Wavelength modulation range

Claims (8)

A first light source that emits first light having a wavelength for detecting a substance to a detection area;
A second light source that emits second light having a wavelength for measuring distance to the detection area;
A distance measuring unit that measures the distance to the irradiation position based on the reflected light of the second light reflected by the irradiation position in the detection area;
A gain adjusting unit that adjusts an output gain of the first light according to a measurement result of the distance measuring unit;
A substance that detects the presence or absence of the substance in the detection area based on the reflected light of the first light that is reflected at the irradiation position by the first light whose output gain has been adjusted by the gain adjusting unit. A detector,
In the scanning of the first light and the second light in the detection area, the irradiation position where the second light is irradiated precedes the irradiation position where the first light is irradiated. Irradiated
Substance detection device. The substance detection device according to claim 1,
When the emission of the first light and the emission of the second light with respect to the detection area are scanned along a predetermined direction, the first light source is positioned at the irradiation position of the immediately preceding second light. Emitting the first light to irradiate the first light;
Substance detection device. The substance detection device according to claim 2,
The first light source and the second light source are fixed to a base;
The first light source and the second light source scan the emission of the first light and the emission of the second light along the predetermined direction according to the turning of the base.
Substance detection device. The substance detection device according to claim 3,
The first light source and the second light source are irradiated so that the irradiation position of the first light and the irradiation position of the second light are shifted by one irradiation position in the detection area. Fixed to the base,
Substance detection device. The substance detection device according to claim 2,
When the emission of the first light and the emission of the second light with respect to the detection area are reciprocated and scanned along the predetermined direction, in either the forward direction or the backward direction, At the time of switching the scanning direction, the irradiation direction of the first light and the second light are such that the irradiation position of the second light precedes the irradiation position of the first light by one irradiation position. An irradiation control unit that crosses the irradiation direction of
Substance detection device. The substance detection device according to claim 1,
An image generation unit for generating image data of the substance detected by the substance detection unit;
An image output unit that outputs image data of the substance generated by the image generation unit,
Substance detection device. A substance detection device according to claim 6;
An imaging device that captures a visible light image of the detection area;
A monitor device that superimposes and displays the image data of the substance output by the image output unit on the data of the visible light image captured by the imaging device,
Substance detection system. A substance detection method in a substance detection apparatus having at least a first light source and a second light source,
From the second light source, the measurement light having the distance measurement wavelength is emitted to the detection area,
Measure the distance to the irradiation position based on the reflected light of the measurement light reflected by the irradiation position in the detection area,
According to the distance to the irradiation position obtained by the measurement, adjust the output gain of the detection light having a wavelength for detecting the substance,
From the first light source, the detection light whose output gain is adjusted is emitted to the detection area,
Detecting the presence or absence of the substance in the detection area based on the reflected light of the detection light reflected at the irradiation position, the detection light having the output gain adjusted;
In the scanning of the detection light and the measurement light in the detection area, the irradiation position irradiated with the detection light is irradiated in time earlier than the irradiation position irradiated with the measurement light.
Substance detection method.

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