JP6265365B2 - Measuring system - Google Patents

Description

  The present invention relates to a measurement system that measures the state of an object at high speed over a wide area by measuring scattered light from the object while irradiating an object at a long distance with laser irradiation.

  As a technique for measuring scattered light in response to pulsed laser irradiation and analyzing the properties of objects at a long distance, there is a technique called bistatic LIDAR (Light Detection and Ranging) (Non-Patent Document 1, (See Patent Document 1).

  The conventional bistatic type LIDAR apparatus detects angle scattered light or forward scattered light from a remote object, so that it can detect relatively high-intensity light, and the concentration of the object including aerosol and particles. Information on size, refractive index, etc. can be measured with high sensitivity and high resolution.

  However, in the conventional bistatic type LIDAR device, it is necessary to precisely synchronize between the transmission device and the reception device (see, for example, Patent Document 1), and the synchronization accuracy between the transmission and reception devices is maintained as the distance increases. It becomes difficult to measure accurately as the area becomes wider.

IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL.GE-20, NO.3, JULY 1982, 229-235

JP 2004-309367 A

  The present invention has been made in view of the above background, and does not require precise synchronization between the transmitting device and the receiving device, and is relatively fast and precise with respect to the atmosphere that spreads over a wide area relatively easily. An object is to provide a measurement system that can be constantly monitored.

In order to achieve the above object, a measurement system according to the present invention emits a pulsed laser beam, changes an emission direction of the laser beam by at least one-dimensional scanning, and illumination that operates the illumination unit. An ejection device having a drive unit, an imaging device that collectively detects non-rear-type scattered light from a target illuminated by a laser beam whose emission direction is changed by an illumination unit, and a predetermined angle of view; and an imaging device A light-receiving device that has an image-capturing drive unit that causes the image-capturing device to capture an image in synchronization with a trigger unit that is attached to the light-receiving device and that is arranged apart from the ejecting device and performs a self-triggered operation independent of the ejecting device With .

  According to the above measurement system, the non-rear scattered light from the object illuminated by the pulsed laser beam is collectively detected by one-dimensional scanning or more, so the state of the object over a wide area is collectively detected. can do. At this time, since the imaging drive unit causes the imaging device to capture an image in synchronization with a trigger unit attached to the imaging device, the scattered light from the target corresponding to the pulsed laser beam is selectively detected and the intensity Information can be obtained, and azimuth information (for example, azimuth angle, elevation angle, etc.) of the object can be obtained from the position on the image. As a result, for example, various types of information relating to the density distribution of aerosols in the atmosphere can be easily obtained with relatively high reliability.

  According to a specific aspect of the present invention, the measurement system further includes an arithmetic processing unit that determines a two-dimensional or higher distribution of the scattering coefficient based on the image signal captured by the imaging device. The estimated value of the scattering or extinction coefficient of the target along the optical path can be evaluated based on the scattered light in the image captured by the imaging device, that is, the intensity and position of the detected light, and the calculation is performed by gradually changing the optical path. The distribution of the two-dimensional or three-dimensional scattering coefficient or extinction coefficient can be determined by the processing unit.

  According to another aspect of the present invention, the arithmetic processing unit calculates, for example, a three-dimensional scattering coefficient distribution by inverse analysis from predetermined initial information. That is, when the scattering coefficient or the extinction coefficient is known for a known optical path, the distribution of the two-dimensional or three-dimensional scattering coefficient or the extinction coefficient in the object is calculated by performing inverse analysis as predetermined initial information. It becomes possible.

  According to still another aspect of the present invention, the illumination unit is disposed on the light exit side of the first and second polygon mirrors, the first and second polygon mirrors rotating around the orthogonal first and second rotation axes, respectively. The first optical element that reduces the angular range of light incident on the reflecting surface of the second polygon mirror and the angle of the light before being incident on the first optical element disposed on the light exit side of the second polygon mirror are proportional to each other. The optical scanning part which has the 2nd optical element to restore | restore automatically. In this case, the first optical element arranged on the light exit side of the first polygon mirror reduces the angle range of light rays incident on the reflecting surface of the second polygon mirror, and is arranged on the light exit side of the second polygon mirror. Since the angle of the light beam before the second optical element is incident on the first optical element is proportionally restored, even if the angle range of scanning by the first and second polygon mirrors is relatively large, distortion in the emission direction is reduced. Scanning can be performed at an accurate angle with reduced.

  According to still another aspect of the present invention, the first optical element substantially matches the incident angles along a predetermined plane parallel to the second rotation axis of the light incident on the reflecting surface of the second polygon mirror, The second optical element has an emission angle along another predetermined plane parallel to the second rotation axis of the light beam reflected by the reflection surface of the second polygon mirror, and the light beam reflected by the reflection surface of the first polygon mirror. It is made to substantially coincide with the injection angle along a predetermined plane parallel to the second rotation axis. Thereby, the deflection angle of the reflection by the first polygon mirror is maintained, and simple two-dimensional scanning in which the first polygon mirror and the second polygon mirror are controlled by the same method becomes possible.

  According to still another aspect of the present invention, the imaging device includes a photoelectric imaging tube that detects an image including scattered light, and the trigger unit is provided along with the photoelectric imaging tube and extracts a signal from the imaging device. Set the timing. In this case, weak scattered light that is difficult to predict can be imaged with high sensitivity in parallel with the detection light by a photoelectric imaging tube or the like, and a high-speed event can be accurately recorded.

According to still another aspect of the present invention, an imaging device includes a solid-state imaging device that is one of a CCD type imaging device and a CMOS type imaging device that detects an output of an image intensifier as a photoelectric imaging tube, The solid-state imaging device is operated based on the timing signal output from the trigger unit. In this case, it is possible to perform high-precision measurement by operating the solid-state imaging device at high speed in synchronization with the photoelectric imaging tube.

It is a schematic diagram explaining the whole measuring system of an embodiment. It is a block diagram explaining the injection device side of a measurement system. It is a perspective view explaining the optical system part of a scanning device main body among injection devices. It is a conceptual diagram which expands and demonstrates an optical system part. (A) is a figure explaining an example of the scanning pattern of the laser beam by an optical system part, (B) is a perspective view explaining the observation by a light-receiving device. It is a figure explaining the light-receiving device side of a measurement system. It is a conceptual diagram of the side cross section explaining the optical amplification part etc. of a light-receiving device. It is a figure explaining the imaging device of a light-receiving device. It is a block diagram which illustrates notionally the main control part of a light-receiving device. It is a principle figure explaining one measuring method using the measuring system of an embodiment.

  Hereinafter, a measurement system according to an embodiment of the present invention will be described in detail with reference to the drawings.

  A measurement system 1000 according to the embodiment shown in FIG. 1 is for monitoring the state of aerosols (contaminant particulates and the like) in the air in real time, and includes an emission device 100 on the light irradiation side and a light receiving device 200 on the light detection side. And as a set. The injection device 100 has a main body 1a and a gantry 1b, and the light receiving device 200 also has a main body 2a and a gantry 2b. The emitting device 100 and the light receiving device 200 are fixedly arranged, for example, about several tens km apart on the ground surface. From the emitting device 100, pulsed laser light L1 is emitted as illumination light so as to be scanned in a two-dimensional direction, and the object OB spread over a wide area illuminated by the laser light L1 is a non-rear type. Detection light L2 is emitted as scattered light. The light receiving device 200 selectively detects the weak detection light L2 from the object OB by the self-trigger function. In addition, although the injection | emission apparatus 100 and the light-receiving device 200 are performing the operation | movement which cooperated, the exact synchronous operation which synchronizes with a common trigger signal is not performed.

  As shown in FIG. 2, the emission device 100 includes a light source device 10 that emits laser light in pulses, a scanning device main body 20 that scans laser light from the light source device 10, and each component that constitutes the emission device 100. A main control unit 101 which is a scanning control unit and an imaging control unit that comprehensively controls the operation of the above. Here, the light source device 10 and the scanning device main body 20 function as an illumination unit that changes the emission direction of the pulsed laser light L1 by two-dimensional scanning, and the main control unit 101 operates the illumination unit. It functions as an illumination drive unit. This injection device 100 irradiates pulsed laser light so as to have an angular direction distributed discretely and substantially uniformly toward the atmosphere.

  The light source device 10 operates under the control of the main control unit 101, and includes a laser generator 11 and an oscillation drive device 12. The laser generator 11 is a pulse-type laser oscillator, and for example, a diode-excited solid laser incorporating an electro-optical Q switch can be used. The oscillation driver 12 is a Q switch trigger circuit, and causes the laser generator 11 to oscillate at a desired timing. In other words, the oscillation drive device 12 receives the trigger pulse from the main control unit 101 and operates the Q switch of the laser generator 11 to emit, for example, periodic laser light RA as a light beam from the laser generator 11.

  The scanning device main body 20 includes an optical unit 21 including a first polygon mirror 51 and a second polygon mirror 52, a first motor drive unit 23 for the first polygon mirror 51, and a second motor for the second polygon mirror 52. Pulse generation for synchronizing and operating the drive unit 24, the mirror rotation control unit 25 for controlling the operation of the first and second motor drive units 23, 24, the mirror rotation control unit 25, the light source device 10 and the like Device 27.

  As shown in FIG. 3, the optical unit 21 includes a first polygon mirror 51 that rotates about the first rotation axis AX1, a second polygon mirror 52 that rotates about the second rotation axis AX2, and a first polygon mirror. The first optical element 53 that adjusts the state of the laser beam RA1 that is a light beam emitted from the first polygon mirror 51 and the light emission side of the second polygon mirror 52 are arranged on the light emission side of the first polygon mirror 51. The second optical element 54 that adjusts the state of the laser beam RA2 that is a light beam emitted from the second polygon mirror 52, the first drive unit 55 that rotates the first polygon mirror 51, and the second polygon mirror 52 are rotated. And a second drive unit 56 to be operated. As shown in FIG. 2, the optical unit 21 is provided with one or more first sensors 57 that are mirror surface detectors attached to the first polygon mirror 51, and the second polygon mirror 52 includes Along with this, one or more second sensors 58 which are mirror surface detectors are provided.

  The first rotation axis AX1 of the first polygon mirror 51 extends parallel to the Z axis, and the second rotation axis AX2 of the second polygon mirror 52 is the first rotation axis AX1, that is, the X axis perpendicular to the Z axis. It extends parallel to. The reflective surface 51a of the first polygon mirror 51 reflects the laser beam RA0 from the light source device 10 of FIG. 2 and emits the laser beam RA1 that is the first stage scanning beam. The reflection surface 52a of the second polygon mirror 52 reflects the laser light RA1 reflected by the reflection surface 51a of the first polygon mirror 51 and passed through the first optical element 53, and laser light RA2 which is the second stage scanning light. Inject. The laser beam RA2 from the reflecting surface 52a of the second polygon mirror 52 passes through the second optical element 54. More specifically, the original laser beam RA0 is incident on the reflecting surface 51a of the first polygon mirror 51 from a direction parallel to the XY plane and close to the X axis. The laser beam RA1 deflected by the reflection at the reflecting surface 51a to become the first-stage scanning light passes through the first optical element 53 and is reflected from the second polygon mirror 52 from the direction parallel to the Y axis. Incident on 52a. The laser beam RA2, which is deflected by the reflection on the reflecting surface 52a and becomes the second stage scanning light, passes through the second optical element 54, thereby reproducing the first stage scanning state and scanning two-dimensionally. The light beam to be emitted, that is, the laser beam L1 emitted from the emission device 100 shown in FIG.

  Here, the laser beam RA1 that is the first-stage scanning light is scanned by the first polygon mirror 51 so as to radiate radially within a predetermined plane parallel to the XY plane. To be parallel. Therefore, the first optical element 53 is an aspheric cylindrical lens in consideration of accuracy improvement. The optical axis AXI of the first optical element 53 is assumed to be parallel to the Y axis, and the first optical element 53 has a curvature in the XY section and has no curvature in the YZ section.

  The laser beam RA2 that is the second-stage scanning beam is scanned by the second polygon mirror 52 so as to diverge radially in a predetermined plane parallel to the plane including the second rotation axis AX2, that is, the XZ plane, The optical element 54 restores the angle of the laser beam RA1 before entering the first optical element 53 in the non-scanning direction. Therefore, the second optical element 54 is an aspheric toric lens in consideration of accuracy improvement. The optical axis AXO of the second optical element 54 is assumed to be parallel to the YZ plane, and the second optical element 54 has a curvature in a cross section parallel to the X axis, and has a curvature in the YZ cross section. .

  As described above, the first polygon mirror 51 deflects the laser beam RA1 that is the source of the laser beam RA2, and the scanning in the X-axis direction, that is, the vertical direction is performed in cooperation with the first and second optical elements 53 and 54. Done. Further, the laser beam RA2 is deflected by the second polygon mirror 52, and scanning in the YZ in-plane direction, that is, the lateral direction is performed. That is, the first and second polygon mirrors 51 and 52 and the first and second optical elements 53 and 54 scan the laser beam RA two-dimensionally in the vertical and horizontal directions.

  FIG. 4 is a diagram conceptually illustrating scanning in the X-axis direction, and the optical path is developed with reference to a predetermined plane parallel to the XY plane. In the figure, the laser beam RA1 from the reflecting surface 51a of the first polygon mirror 51 is scanned within an angular range of ± 2θ. The laser beam RA1 passes through the first optical element 53 and is temporarily parallel to the optical axis AX or Y axis and is incident on the reflecting surface 52a of the second polygon mirror 52. That is, the incident angle of the laser beam RA1 incident on the reflecting surface 52a of the second polygon mirror 52 is the same at any position along a predetermined plane parallel to the second rotation axis AX2. As a result, the laser beam RA2 reflected by the reflecting surface 52a of the second polygon mirror 52 is maintained parallel to the optical axis AX regardless of the rotation angle of the first polygon mirror 51, and is applied to the second optical element 54. Incident. In the second optical element 54, for example, the focal length f2 in the X-axis direction is equal to the focal length f1 in the X-axis direction of the first optical element 53, and the laser light RA2 that has passed through the second optical element 54 is rotated second. Proceeding along another predetermined plane parallel to the axis AX2, once converged and diverged, the laser beam RA1 is scanned in the same angular range as the scanned angular range ± 2θ. That is, the second optical element 54 restores the angle of the laser light RA1 before entering the first optical element 53. More specifically, the second optical element 54 extends along another predetermined surface parallel to the second rotation axis AX2 (see FIG. 3) of the laser light RA2 reflected by the reflecting surface 52a of the second polygon mirror 52. The final emission angle is made to substantially coincide with the original emission angle along a predetermined plane (XY plane) parallel to the second rotation axis AX2 of the light beam reflected by the reflection surface 51a of the first polygon mirror 51.

  The first optical element 53 is a cylindrical lens, and has a three-dimensional outer shape as a locus obtained by moving the cross section (XY cross section) shown in FIG. 3 in the Z direction perpendicular to the optical axis AX. The cross section on the optical axis including the X-axis direction of the first surface and the second surface of the second optical element 54 is the same as the cross section including the X-axis direction of the first surface and the second surface of the first optical element 53. . However, the second optical element 54 is a toric lens, and passes through a certain reference point set on the optical axis AXO through the same cross section as the first optical element 53, and is a rotation axis (not shown) parallel to the X axis. Has a three-dimensional outer shape as a trajectory rotated around.

  In the above description, the focal length f2 in the X-axis direction of the second optical element 54 is equal to the focal length f1 in the X-axis direction of the first optical element 53, but the focal length f2 is different from the focal length f1. You can also. In this case, the angle range in which the laser beam RA2 is scanned is different from the angle range ± 2θ in which the laser beam RA1 is scanned, but has a proportional relationship multiplied by a coefficient. That is, also in this case, the second optical element 54 proportionally restores the angle of the laser light RA1 before entering the first optical element 53. Furthermore, the focal length f2 in the X-axis direction of the second optical element 54 can be negative as well as positive, and also in this case, the laser beam RA2 can be scanned so as to diverge in the X direction.

FIG. 5A is a diagram for explaining an example of the scanning pattern of the laser light RA by the optical unit 21 of FIG. The laser beam RA is changed in the YZ plane by the second polygon mirror 52 while the angle Θ corresponding to the X-axis direction is periodically changed by a predetermined amount (unit scanning angle) by the first polygon mirror 51 in the target area AR. Irradiation is performed discretely in an angle direction in which an angle Φ corresponding to a specific direction is periodically changed by a predetermined amount (unit scanning angle). In the illustrated example, the unit scanning angle by the first polygon mirror 51 and the unit scanning angle by the second polygon mirror 52 are substantially equal. However, the unit scanning angle by the first polygon mirror 51 and the second polygon mirror 51 are the same. Either one of the unit scanning angles by the mirror 52 can be made relatively small.
FIG. 5B is a diagram for explaining a situation where the scanning pattern of the laser beam RA (L1) by the emission device 100 is observed from the light receiving device 200 side. The laser beam L1 emitted from the injection apparatus 100 performs laser scanning without leakage in the laser irradiation area VA that is a three-dimensional space in the sky. As a result, in the light receiving device 200, the detection light L2 is obtained as scattered light from the laser irradiation area VA illuminated by the laser light L1 from the emission device 100 only by capturing an image with the field of view fixed. Here, the front surface (virtual surface perpendicular to the optical axis of the light receiving device 200) SP of the laser irradiation area VA and the detection light L2 from the back surface parallel to this are detected as a two-dimensional distribution pattern P1, and the depth The pattern P2 arranged in the direction is detected over time as changing in a pulse shape on the same line of sight. Note that the laser light L1 from the emission device 100 can have a small extent as desired by adjusting the beam expander provided in the laser generator 11 shown in FIG. 2, and receives the dots (detection units) of the pattern P1. It can be as low as or less than the resolution of the device 200. Further, the scanning of the laser beam L1 on the front surface SP of the laser irradiation area VA can be performed by adjusting the X-axis and Y-axis directions of FIG. 3 so that the inclination of the scanning pattern shown in FIG. The main scanning direction can be set to, for example, a horizontal direction or a vertical direction. In other words, the main scanning of the laser beam L1 can be made to coincide with the X ′ direction and the Y ′ direction in FIG. It becomes easy to detect scattered light from the line as a lattice point. The method of selecting the biaxial scanning plane for the emission of the laser light L1 is geometrically determined in advance so that the light receiving efficiency of the pixels on the light receiving surface of the light receiving device 200 is maximized.

  Returning to FIG. 2, the first sensor 57 provided in association with the first polygon mirror 51 is a unit in which the light source and the light detection element are integrated, and the inspection light is incident on the reflection surface 51a to be reflected. By detecting the reflected light, it is possible to detect information related to the rotation posture of the first polygon mirror 51, and it is used to detect the rotation speed and the starting point of the rotation of the first polygon mirror 51. The second sensor 58 provided along with the second polygon mirror 52 also has the same structure as the first sensor 57, and detects the reflected light that is reflected by making the inspection light incident on the reflecting surface 52a. The information about the rotation posture of the second polygon mirror 52 can be detected, and is used to detect the rotation speed and the starting point of the rotation of the second polygon mirror 52. Detection outputs of the first and second sensors 57 and 58 are transmitted to the mirror rotation control unit 25 and the main control unit 101 via first and second motor drive units 23 and 24 described later.

  The first motor drive unit 23 operates under the control of the mirror rotation control unit 25, and rotates the motor at a constant speed by supplying a drive voltage to the motor incorporated in the first drive unit 55. The first drive unit 55 incorporates an encoder in association with the motor, and outputs an encoder signal indicating the rotation angle of the first polygon mirror 51 driven by the first drive unit 55 to the mirror rotation control unit 25. .

  The second motor drive unit 24 operates under the control of the mirror rotation control unit 25 and rotates the motor at a constant speed by supplying a drive voltage to the motor incorporated in the second drive unit 56. The second drive unit 56 incorporates an encoder in association with the motor, and outputs an encoder signal indicating the rotation angle of the second polygon mirror 52 driven by the second drive unit 56 to the mirror rotation control unit 25. .

  The mirror rotation control unit 25 incorporates a signal processing circuit such as a DSP, processes the encoder signals from the first and second motor drive units 23 and 24, and uses them for feedback. That is, the mirror rotation control unit 25 directly monitors the rotation state of the first and second polygon mirrors 51 and 52 to keep the rotation angle constant.

  The pulse generator 27 generates a reference pulse for operating the scanning device main body 20 under the control of the main control unit 101. The reference pulse from the pulse generator 27 is used for the operation of the mirror rotation control unit 25.

The main control unit 101 is a device composed of a computer or the like. The main control unit 101 operates the pulse generator 27 and the mirror rotation control unit 25 as appropriate, and the first and second polygons via the first and second motor drive units 23 and 24. Encoder signals indicating the rotation angles of the mirrors 51 and 52 are received. The main control unit 101 outputs a trigger signal for generating a laser pulse to the oscillation driving device 12 of the light source device 10 in synchronization with the rotation angles of the first and second polygon mirrors 51 and 52. That is, the main control unit 101 operates the light source device 10 in synchronization with the rotation angles of the first and second polygon mirrors 51 and 52 to thereby perform two-dimensional scanning of the laser light RA and pulse generation timing. Control. The main control unit 101 includes a communication unit 30 that enables communication with an external network NW.
The main control unit 101 can acquire the position coordinates of the emission device 100 using GPS or the like, and can transmit this position information to the light receiving device 200 via the communication unit 30.

  Hereinafter, the light receiving device 200 used as a pair with the emission device 100 of FIG. 2 will be described with reference to FIG. 6 and the like. The light receiving device 200 is, for example, a Schmitt camera type observation device, and includes an imaging optical unit 60 that is a relatively wide-angle infinity imaging system, and an optical amplification unit that amplifies short pulse weak light acquired by the imaging optical unit 60. 70, a detection unit 80 that detects an image obtained by the optical amplification unit 70 at high speed, and a main control unit 201 that is a scanning control unit and an imaging control unit that comprehensively controls the operation of each unit constituting the light receiving device 200. With. Here, the imaging optical unit 60, the optical amplification unit 70, and the detection unit 80 collectively detect non-rear scattered light from the object OB illuminated by the laser light from the emission device 100 with a wide angle of view. The detection unit 80 and the main control unit 201 function as an imaging drive unit for operating the imaging device.

  The imaging optical unit 60 of the light receiving device 200 includes an imaging mirror 61, a correction plate 62, and a gantry device 63. In the imaging optical unit 60, the imaging mirror 61 has a reflecting surface 61a, which is a spherical surface, a paraboloid, or other aspherical surface, as a reflecting mirror for imaging. The detection light L2 incident on the light receiving device 200 is condensed to form an observation target image on the image forming position IS. The correction plate 62 is a thin lens, and at least one of the light incident surface and the light exit surface is an aspheric surface or the like, and corrects the optical path of the light beam DL incident on the imaging mirror 61. The correction plate 62 is not limited to one having a single configuration as shown in the figure, and may have a plurality of configurations.

  As shown in detail in FIG. 7, the optical amplification unit 70 includes an image transmission unit 70a and an image intensifier 70b. The former image transmission unit 70a has a role of guiding an image formed on the image forming position IS spreading two-dimensionally to an optical window of the image intensifier 70b, and a light beam from the object by an optical filter 74 described later. DL can be limited to measurement light in a specific wavelength range.

  The image transmission unit 70 a includes a light transmission substrate 71, a lens array 72, a light guide array 73, and an optical filter 74. Portions of the light transmitting substrate 71, the lens array 72, the light guide array 73, and the like constituting the image transmitting unit 70a are supported by frame-like supports 75a and 75b arranged along a plane perpendicular to the optical axis OA. It is fixed integrally. Here, the support body 75b is also a part of the input unit 76 described later.

The light transmission substrate 71 in the image transmission unit 70a is a curved thin spherical shell member. The outside of the light transmitting substrate 71 is a convex spherical surface, which is an incident surface 71a corresponding to the image forming position IS. The inner side of the light transmitting substrate 71 supports the lens array 72 in a state of being arranged in a spherical shell shape or a dome shape. The lens element 72e constituting the lens array 72 has a role of reducing the exit angle of the light beam passing through the lens array 72 from the incident angle, and reduces the exit NA smaller than the incident NA so as to be close to parallel light. Perform numerical aperture conversion to decrease. Thereby, the incident angle of the light beam incident on the optical filter 74 at the next stage can be reduced. The light guide array 73 is disposed to face the lens array 72 and has a structure in which a large number of elongated light guide elements 73e are bundled. These light guide elements 73e are arranged on a one-to-one basis corresponding to the large number of lens elements 72e constituting the lens array 72. The exit surface 73b of the light guide array 73 faces the input portion 76 of the image intensifier 70b, and forms a concave spherical surface as a whole.
The pair of the lens element 72e of the lens array 72 and the light guide element 73e of the light guide array 73 is aligned so as to be aligned with the direction of the light beam of the laser light that is planned and emitted in advance. It can be arranged to increase the collection efficiency. In this case, the collection efficiency can be improved relatively easily by aligning the light receiving device 200 with the optimal position so that the sensitivity to the emitted laser light is maximized as a whole.

  The optical filter 74 is disposed so as to be inserted into a thin gap GA formed between the lens array 72 and the light guide array 73. The optical filter 74 selectively transmits light having a predetermined wavelength. For example, the optical filter 74 is a band-pass filter that allows specific ultraviolet light or infrared light to pass in a narrow band. The optical filter 74 is divided into, for example, three regions having different wavelength characteristics, and the arrangement of the three regions with respect to the lens array 72 can be changed by rotation or the like. Thereby, images in different wavelength bands can be detected in parallel with a slight time difference. The optical filter 74 can be replaced with another type of optical filter.

The latter image intensifier 70b in the optical amplifying unit 70 amplifies a weak image formed by the imaging mirror 61 and transmitted by the image transmission unit 70a. The image intensifier 70b includes an input unit 76 for photoelectrically converting the imaging light, an electrostatic convergence system 77 for converging the electrons after the photoelectric conversion, and an image obtained by converting the incident electrons in the converged state into light. And an output portion 78 to be formed. Here, the input unit 76 and the electrostatic focusing system 77 are photoelectric imaging tubes for detecting scattered light. The input unit 76 of the image intensifier 70b is fixed to one end on the open side of the metal container body 79. The input unit 76 includes, for example, an optical window 76a that is a fiber optic plate having a flat surface on the outside and a concave curved surface on the inside, and photoelectric conversion is performed on the inside of the optical window 76a by vapor deposition of a photoelectric conversion material having predetermined characteristics. A surface 76c is formed. The electrostatic focusing system 77 is supported on the inner surface of the side wall of the container main body 79. The electrostatic focusing system 77 has a plurality of electrode portions 77a to 77d for electron focusing. The output unit 78 is fixed to the bottom of the container body 79. The output unit 78 is formed of, for example, a fiber optic plate 78a, and a phosphor having a predetermined characteristic is applied to the incident surface 78b. The incident surface 78 b of the fiber optic plate 78 a is disposed at the position of the imaging surface of the electrostatic focusing system 77 and has a surface shape that matches the imaging surface of the electrostatic focusing system 77. A microchannel plate (MCP) may be disposed in front of the fiber optic plate 78a. In this case, incident electrons are multiplied by the MCP, and a fluorescent image corresponding to the electrons multiplied by the fiber optic plate 78a is formed.
There is also a system in which a semiconductor pixel detector is arranged instead of the fiber optic plate with the phosphor screen attached to the output surface to directly detect the incidence of electrons and read out the current output signal for each pixel. In that case, a relay optical system 81 and a trigger sensor (coarse image detection unit 83 and the like), which will be described later, are omitted, and the trigger determination circuit and the readout sensor are integrated.

  The detection unit 80 detects the image amplified by the image intensifier 70b of the light amplification unit 70 as an electrical signal. The detection unit 80 includes a relay optical system 81, a fine image detection unit 82, a coarse image detection unit 83, and a drive circuit 84. The relay optical system 81 includes a distributor 81a disposed on the upstream side of the optical path along the optical axis OA, a main body optical system 81b disposed on the downstream side of the optical path from the distributor 81a, and a trigger branched by the distributor 81a. And a branching optical path part 81c for detecting light. Of the relay optical system 81, the distributor 81a is a beam splitter.

  As shown in FIG. 8, the relay optical system 81 of the detection unit 80 has an image of the output surface 78 c of the output unit 78 provided in the image intensifier 70 b approximately on the imaging surface 82 i of the fine image detection unit 82. Project with. The relay optical system 81 is telecentric on the output surface 78c side of the output unit 78, that is, on the object side, and is non-telecentric or telecentric on the imaging surface 82i side of the fine image detecting unit 82, that is, on the image side.

  The distributor 81a is a prism having a built-in beam split mirror SM which is a kind of half mirror. The distributor 81a distributes the fluorescent image on the output surface 78c of the image intensifier 70b into two fluorescent images having a predetermined intensity, that is, a first fluorescent image and a second fluorescent image. The light beam of the first fluorescent image that travels straight through the beam split mirror SM of the distributor 81a is guided to the first optical path OP1, passes through the main body optical system 81b, and is incident on the imaging surface 82i of the solid-state imaging device 82a. The light beam of the second fluorescent image reflected and bent by the beam split mirror SM of the distributor 81a is guided to the second optical path OP2 and is incident on the imaging surface 83i of the coarse image detector 83 made of a photoelectric imaging tube. The distributor 81a has a predetermined ratio (α (transmittance) / β (reflectance)) between the intensity of light transmitted through the beam split mirror SM and the intensity of light reflected without being transmitted. Is set. Specifically, when the reduction in transmittance due to the absorption of the distributor 81a itself is not considered, for example, the transmittance α = 70% and the reflectance β = 30% are set. The α / β ratio can be arbitrarily set, but is generally larger than 1 from the viewpoint of increasing the amount of light of the first fluorescent image incident on the imaging surface 82i of the fine image detector 82. desirable.

  The main body optical system 81 b is a projection lens composed of a plurality of lenses, and bears the projection function of the relay optical system 81.

  The branching optical path unit 81 c projects the image of the output surface 78 c of the image intensifier 70 b on the imaging surface 83 i of the coarse image detection unit 83 at approximately the same magnification. The branching optical path portion 81c places the highest importance on brightness, and is non-telecentric on both the object side and the image side. The distributor 81a is also a part of the branch optical path portion 81c.

  The fine image detection unit 82 includes, for example, a solid-state image sensor 82a that is a CMOS image sensor, and a drive circuit 82b that causes the solid-state image sensor 82a to perform an imaging operation, and is output from the position / timing control circuit 84b of the drive circuit 84. Based on the timing signal, the solid-state image sensor 82a can perform an imaging operation. The solid-state imaging device 82a has an imaging surface 82i. The entire imaging surface 82i is divided into m (for example, 12) rows in the y direction and n (for example, 12) columns in the x direction so as to divide the imaging surface 82i into a grid. As m rows × n columns = A (for example, 144) channel local area AR1. Each local area AR1 functions independently as a CMOS type image sensor, and two-dimensional image detection is possible. Each local area AR1 can perform an imaging operation at different timings, and independently performs an imaging operation based on an individual timing signal output from the position / timing control circuit 84b. That is, the output surface 78c of the output unit 78 is disposed at a conjugate position of the imaging surface 82i of the solid-state imaging device 82a via the main body optical system 81b, and is virtually m by the local region AR1 that constitutes the imaging surface 82i. It is possible to observe by dividing into rows × n columns = A channel.

  The coarse image detector 83 is a photoelectric imaging tube including a multi-anode photomultiplier, and its imaging surface 83i has m (for example, 12) rows in the y direction and n (for example, 12) columns in the x direction as a whole. It has a divided area AR2 of m rows × n columns = A (for example, 144) channels. That is, the coarse image detection unit 83 has a mesh dynode corresponding to the segment area AR2 of the A channel, and the second image on the imaging surface 83i is only from the anode of the dynode to which the second fluorescent image is input with a predetermined intensity or more. 2 A current obtained by photoelectric conversion of the fluorescence image is output. Note that the time required for the light beam of the second fluorescent image to enter the imaging surface 83i and output the current is about 1 nanosecond. The coarse image detection unit 83 is able to identify the divided region AR2 on which the luminous flux of the second fluorescent image has entered, together with the appearance timing, based on the current output from each anode. In other words, the output surface 78c of the image intensifier 70b is virtually divided into m rows × n columns = A channel by the divided area AR2 constituting the imaging surface 83i of the coarse image detector 83, and can be individually monitored. It has become. Note that the virtual segmented area on the output surface 78c of the image intensifier 70b corresponding to the segmented area AR2 also corresponds to the local area AR1 of the fine image detecting unit 82. Here, the segmented area in which the weak event appears in the output surface 78c is referred to as the appearing area.

  The drive circuit 84 includes a logic circuit unit 84a that operates based on the detection signal of the coarse image detection unit 83, and a position / timing control circuit 84b that operates based on the output of the logic circuit unit 84a. The drive circuit 84 functions as the trigger unit 88 by cooperating with the branch optical path unit 81 c of the relay optical system 81. This trigger unit 88 monitors the light flux of the second fluorescent image distributed by the distributor 81a of the relay optical system 81, and appropriately captures the first fluorescent image by the solid-state image sensor 82a of the fine image detection unit 82. And

  The logic circuit unit 84a includes, for example, a wave height discriminator, and whether or not the current output from each anode of the coarse image detection unit 83 exceeds a predetermined threshold value, that is, the appearance of the weak detection light L2 or the light beam DL. The timing is detected as binary information, for example. Specifically, the logic circuit unit 84a thresholds the current output from the anode of an arbitrary row constituting the coarse image detection unit 83 and the current output from the anode of an arbitrary column. The second fluorescent image detected by the detection unit 83 is converted into position information and timing information regarding each of the x direction (m rows) and the y direction (n columns). That is, when the light beam of the second fluorescent image is incident on the specific segmented area AR2 of the coarse image detecting unit 83, the logic circuit unit 84a outputs information on the time, position, and the like, thereby causing the image intensifier 70b to output the information. For the detected weak detection light L2 or light beam DL, the time, position, moving direction, etc. of the detection light L2 can be obtained.

  The position / timing control circuit 84b includes, for example, a filter, a delay circuit, and the like, and is fine based on information output from the logic circuit unit 84a, that is, position information and timing information regarding incidence of the weak detection light L2 or light DL. The image detection unit 82 is operated. Specifically, the segment area AR2 of the coarse image detector 83 and the local area AR1 of the fine image detector 82 are correlated, and the position / timing control circuit 84b includes the second fluorescence in the segment area AR2. A drive signal is sent to the drive circuit 82b of the fine image detector 82 so that the first fluorescent image is picked up in selective synchronization in the local region AR1 of the solid-state image sensor 82a corresponding to the appearing region where the image is detected. Is output. In other words, the imaging operation by the fine image detection unit 82 is limited to the minimum necessary according to the time, position, moving direction, etc., when the weak detection light L2 or the light beam DL detected by the coarse image detection unit 83 is incident. Therefore, it is possible to extract only high-speed and weak events from the output of the image intensifier 70b and to capture images with a high S / N ratio. At this time, the position / timing control circuit 84 b can also adjust the exposure time of imaging by the solid-state imaging device 82 a based on the output of the coarse image detection unit 83.

  Returning to FIG. 6, the gantry device 63 includes a gantry driving unit 63 b, and the imaging optical system including the imaging mirror 61 and the correction plate 62, the light amplification unit 70, and the detection unit 80 are integrated. Can be directed in a specific direction. The gantry device 63 operates under the control of the main control unit 201, and outputs direction information regarding the azimuth angle ζ and elevation angle η of the optical axis OA of the imaging mirror 61 to the main control unit 201. The main control unit 201 includes a communication unit 90 that enables communication with an external network NW.

  FIG. 9 is a block diagram conceptually illustrating the structure of the main control unit 201 of the light receiving device 200 as the arithmetic processing unit. The main control unit 201 is a device composed of a computer or the like, but with a built-in software, the position measurement unit 4a, the azimuth conversion unit 4b, the optical path calculation unit 4c, the coefficient space table 4d, the coefficient evaluation unit 4e, the storage unit 4f, It functions as the arithmetic processing unit 4q and the like. The position measuring unit 4a acquires the position coordinates of the light receiving device 200 using GPS or the like. The azimuth conversion unit 4b calculates a line-of-sight direction or a directional direction (azimuth angle ζj, elevation angle ηj) corresponding to a specific pixel in the detection image based on the direction information of the optical axis OA from the gantry device 63. The optical path calculation unit 4c calculates the optical path in the air from the directivity obtained by the azimuth conversion unit 4b. The coefficient space table 4d stores initial values and calculation results of a three-dimensional distribution such as the extinction coefficient of the upper atmosphere. The coefficient evaluation unit 4e evaluates a calculated value such as a dissipation coefficient based on the luminance of a specific pixel in the image detected by the fine image detection unit 82. The arithmetic processing unit 4q performs a predetermined calculation based on outputs from the fine image detecting unit 82, the azimuth converting unit 4b, the optical path calculating unit 4c, and the like while referring to the storage unit 4f that stores various data necessary for processing. Visualize and display the state of aerosols in the atmosphere.

もしくは、特定点ＯＢｊの受信光強度Ｐ_obs ^jと特定点ＯＢｊに隣接する次の点ＯＢｊ+１の受信光強度Ｐ_obs ^j+1とを用いてこれらの比Ｐ_obs ^j+1／Ｐ_obs ^jを計算する場合、同様の差分ｅ

のいずれかを最小とするようにして、特定点ＯＢｊの散乱係数ＳＣｊ（κ）から次の点ＯＢｊ+１の散乱係数ＳＣｊ+１を決定することができる。例えば、受光装置２００に最も近い点ＯＢ１の散乱係数ＳＣ１が所定の初期情報として既知であるとすれば、上記特定の指向方向又は視線方向に沿った散乱係数ＳＣ１，ＳＣ２，ＳＣ３，…を順次計算（逆解析）することができる。さらに、特定点ＯＢｊと射出装置１００と受光装置２００とを含む観測断面内で仰角を変えつつ同様の逆解析処理等を行うことで、この観測断面内における散乱係数ＳＣの２次元的な分布を得ることができる。上記所定の初期情報は、例えば地上近傍用の別タイプのエアロゾル計測装置の計測結果を利用することができる。以上の手法と同様に、観測断面を変化させつつ同様の逆解析処理等を行うことで、散乱係数ＳＣの３次元的な分布を決定することもできる。以上において、得られた散乱係数ＳＣに基づいて透過率Ｔを修正しつつ再計算を行うことで、計測の信頼性を高めることができる。なお、以上の計算では、散乱係数ＳＣの空間分布の初期値を仮定しているが、計算の便宜上は、大気空間を小セルに分割して各セルに散乱係数ＳＣを当てはめることが行われる。散乱係数ＳＣを当てはめる空間の分割数は、計測システム１０００の用途や仕様に応じて適宜設定することができる。一般的には、空間の分割数が多いほど計測を精密にでき、空間の分割数が少ないほど収束値を得るまでの時間すなわち処理時間を短くできる。受光装置２００による画像取り込みの分解能や射出装置１００によるレーザー光の走査密度は、散乱係数ＳＣに関する空間分割数に対応する値よりも高くできる。この場合、レーザー走査の幾何学的な自由度が増える。一方、受光装置２００による画像取り込みの分解能は、散乱係数ＳＣに関する空間分割数に対応する値程度とすることもできる。この場合、幾何学的な配置を整合させることができ、低コストで迅速な処理が可能になる。 Hereinafter, an example of a method for monitoring the state of aerosol in the atmosphere by the measurement system 1000 will be described with reference to FIG.
First, consider a case where the light receiving device 200 observes scattered light from a specific point OBj illuminated by the emitting device 100. In this case, the received light intensity exists at the transmittance Tj1 on the path Rj1 from the emitting device 100 to the specific point OBj, the transmittance Tj2 on the path Rj2 from the specific point OBj to the light receiving device 200, and the specific point OBj. It depends on the scattering coefficient SCj (κ) of a substance such as aerosol. Here, the scattering coefficient SCj (κ) is a function of the scattering angle κ. The length LG1 of the path Rj1 and the length LG2 of the path R2 are geometrically calculated from the coordinate data regarding the positions of the emission device 100 and the light receiving device 200, the azimuth angle ζj and the elevation angle ηj in the directional direction being observed. The scattering angle κj is calculated similarly.
When the three-dimensional distribution of the atmospheric scattering coefficient SC is known, or when the three-dimensional distribution of the atmospheric scattering coefficient SC is assumed, the scattering coefficient SCj at the specific point OBj is naturally the paths Rj1 and Rj2 before and after that. The transmittances Tj1 and Tj2 can also be calculated.
Here, assuming that the laser beam L1 is scanned away from the light receiving device 200 in a state limited to a specific directing direction or line-of-sight direction, a group of time-series that move away from the observed directing direction. The received light intensity P can be obtained. If the scattering coefficient SCj of any one specific point OBj is known, the following difference e

Alternatively, using the received light intensity P _obs ^j at the specific point OBj and the received light intensity P _obs ^{j + 1 at} the next point OBj + 1 adjacent to the specific point OBj, the ratio P _obs ^{j + 1} / P _obs ^j A similar difference e

As a result, the scattering coefficient SCj + 1 of the next point OBj + 1 can be determined from the scattering coefficient SCj (κ) of the specific point OBj. For example, if the scattering coefficient SC1 of the point OB1 closest to the light receiving device 200 is known as the predetermined initial information, the scattering coefficients SC1, SC2, SC3,... Along the specific pointing direction or line-of-sight direction are sequentially calculated. (Inverse analysis). Further, by performing the same inverse analysis process while changing the elevation angle in the observation cross section including the specific point OBj, the emission device 100, and the light receiving device 200, the two-dimensional distribution of the scattering coefficient SC in the observation cross section is obtained. Can be obtained. As the predetermined initial information, for example, a measurement result of another type of aerosol measurement device for the vicinity of the ground can be used. Similarly to the above method, the same inverse analysis process or the like is performed while changing the observation cross section, whereby the three-dimensional distribution of the scattering coefficient SC can be determined. In the above, the reliability of measurement can be improved by performing recalculation while correcting the transmittance T based on the obtained scattering coefficient SC. In the above calculation, the initial value of the spatial distribution of the scattering coefficient SC is assumed. However, for convenience of calculation, the atmospheric space is divided into small cells and the scattering coefficient SC is applied to each cell. The number of divisions of the space to which the scattering coefficient SC is applied can be appropriately set according to the use and specification of the measurement system 1000. In general, the larger the number of divisions in space, the more precise the measurement, and the smaller the number of divisions in space, the shorter the time until obtaining a convergence value, that is, the processing time. The resolution of image capturing by the light receiving device 200 and the scanning density of the laser light by the emitting device 100 can be higher than the values corresponding to the number of spatial divisions related to the scattering coefficient SC. In this case, the geometric freedom of laser scanning increases. On the other hand, the resolution of image capture by the light receiving device 200 can be about a value corresponding to the number of spatial divisions related to the scattering coefficient SC. In this case, the geometric arrangement can be matched, and rapid processing can be performed at low cost.

  In order to monitor the state of the aerosol or the like as the measurement system 1000, the main control unit 201 of the light receiving device 200 acquires information on the position coordinates and the like from the injection device 100 using the communication unit 90 as the position measurement unit 4a. The main control unit 201 also acquires information related to the scanning pattern, scanning angle range, scanning reference azimuth, and the like of the laser light L1 from the emission apparatus 100. The main control unit 201 calculates the optical path based on the directivity direction (azimuth angle ζj and elevation angle ηj) of the scanned laser light L1 as the azimuth conversion unit 4b and the optical path calculation unit 4c, and is described above as the coefficient evaluation unit 4e. The extinction coefficient or scattering coefficient along the optical path is determined by referring to the coefficient space table 4d by the inverse analysis, and the result is stored in the storage unit 4f. The main control unit 201 can visualize and display the spatial distribution of the extinction coefficient of the upper atmosphere or the aerosol concentration calculated by the above method. By repeating measurement by the measurement system 1000 at intervals of several seconds to several minutes, it is possible to display the dissipation coefficient of the upper atmosphere or the spatial distribution of the aerosol concentration in substantially real time, and to store the fluctuation in an image.

  Specific examples will be described below. For aerosol measurement, the wavelength of the illumination laser beam L1 emitted from the injection apparatus 100 was set to 355 nm, 266 nm, and the like, and the maximum frequency was set to 100 kHz (300 μJ / pulse). In the case of aerosol, when a wavelength of 266 nm is used for signal detection, 355 nm can be used for background detection. Further, for ozone measurement, the wavelength of the illumination laser beam L1 emitted from the injection apparatus 100 was set to 308 nm or the like, and the maximum frequency was set to 100 kHz (250 μJ / pulse). For the cloud bottom, the wavelength of the laser beam L1 for illumination emitted from the emission device 100 is set to 785 nm or the like. When irradiating the laser beam L1 for illumination, for example, the scanning angle by a polygon mirror was 80 ° × 80 °, scanning was performed at 200 × 200 points / second, and the scanning accuracy was 5 arc minutes. The light receiving device 200 was manufactured as a portable type and a fixed wide type. In the case of the portable type, the viewing angle is 42 °, and the pointing direction or the line-of-sight direction can be detected with an accuracy of 0.02 °. In the case of the fixed wide area type, the viewing angle is 25.6 °, and the pointing direction is with an accuracy of 0.4 °. Alternatively, the line-of-sight direction can be detected.

  According to the measurement system 1000 described above, the non-rear scattered light from the object OB illuminated by the pulsed laser beam L1 is detected at a time by one-dimensional scanning or more. The state of the object OB can be detected collectively. At this time, since the drive circuit 84 and the main control unit 201 as the imaging drive unit cause the fine image detection unit 82 to capture an image in synchronization with the trigger unit 88, the object OB corresponding to the pulsed laser beam is used. The intensity information can be obtained by selectively detecting the scattered light, and the azimuth information (for example, azimuth angle, elevation angle, etc.) of the object OB can be obtained from the position on the image. As a result, for example, various types of information relating to the density distribution of aerosols in the atmosphere can be easily obtained with relatively high reliability. This makes it possible to monitor the local air condition over the facility, air pollution inflow from neighboring countries, air pollution trends in urban areas, etc., and 3D real-time imaging lidar (3D-RTIL) that can comprehensively monitor these Can be put into practical use.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and can be implemented in various modes without departing from the gist thereof. Such modifications are also possible.

  In the above-described embodiment, the scanning device main body 20 includes the polygon mirrors 51 and 52 in the emission device 100. However, a galvanometer mirror can be used instead of the polygon mirrors 51 and 52, and the optical elements 53 and 54 can be omitted. . Furthermore, the scanning pattern by the scanning device main body 20 is not limited to the one illustrated in FIG. 5A, and various patterns can be used according to the purpose and target.

  The light receiving device 200 of the above embodiment is an exemplification, and for example, in the light receiving device 200, the image transmission unit 70a of the light amplifying unit 70 can be omitted.

  In the above embodiment, the distributor 81a associated with the relay optical system 81 is used as a part of the trigger unit 88. However, instead of the distributor 81a associated with the relay optical system 81, another method (for example, an image intensifier) is used. The trigger part provided in 70b can also be used.

  In the above embodiment, the fiber optic plate 78a is provided at the output section 78 of the image intensifier 70b. However, the fiber optic plate 78a can be omitted and an electron beam image can be directly detected by the solid-state imaging device 82a. .

  In the above embodiment, the trigger signal is detected in the divided area AR2 in the light receiving device 200, but the trigger signal can also be detected in the pixel unit.

  In the above embodiment, the concentration distribution of aerosol, ozone, etc. in the atmosphere is measured. However, it is also possible to measure the state of the atmosphere and other objects assuming scattering due to other factors. For example, it is possible to apply real-time realization of cloud bottom measurement and turbulent flow monitoring for air traffic control.

  In the above embodiment, the measurement system 1000 includes a pair of the emission device 100 and the light receiving device 200. However, the measurement system is configured by arranging a plurality of pairs of the emission device 100 and the light reception device 200 in, for example, a lattice shape or an array shape. If 1000 is configured, it is possible to observe or measure the atmospheric state in a wide area. Furthermore, by connecting a large number of pairs of the emission device 100 and the light receiving device 200 via a communication network, it is possible to measure and record a wider area of atmospheric conditions and the like in real time. Thereby, exhaustive monitoring in various ranges ranging from several hundred meters to several thousand km can be realized.

  4a ... Position measurement unit, 4b ... Direction conversion unit, 4c ... Optical path calculation unit, 4d ... Coefficient space table, 4d ... Coefficient space table, 4e ... Coefficient evaluation unit, 4e ... Coefficient evaluation unit, 4f ... Storage unit, 4q ... Calculation Processing unit 10 ... Light source device 20 ... Scanner main body 21 ... Optical unit 23,24 ... Motor drive unit 25 ... Mirror rotation control unit 27 ... Pulse generator 51 ... Polygon mirror 51 ... Relay optical system 51, 52 ... polygon mirror, 53, 54 ... optical element, 57, 58 ... sensor, 60 ... imaging optical part, 61 ... imaging mirror, 63 ... gantry device, 70 ... light amplification part, 70a ... image transmission part, 70b: Image intensifier 72: Lens array 73: Light guide array 74: Optical filter 76c Photoelectric conversion surface 77 Electrostatic focusing system, 78 ... output unit, 78a ... fiber optic plate, 80 ... detection unit, 81 ... relay optical system, 81a ... distributor, 82 ... fine image detection unit, 82a ... solid-state image sensor, 83 ... rough image detection 84: drive circuit, 84a: logic circuit unit, 84b ... timing control circuit, 88 ... trigger unit, 100 ... injection device, 101 ... main control unit, 200 ... light receiving device, 201 ... main control unit, 1000 ... measurement system AX ... optical axis, AX1 ... rotation axis, AX2 ... rotation axis, L1 ... laser light, L2 ... detection light, OA ... optical axis, OB ... object.

Claims (7)

Thereby emits pulsed laser light, and an injection device comprising a lighting unit for changing at least one dimension or more scanning emission direction of the laser light, and an illumination drive unit for operating the illumination unit,
An imaging device for detecting collectively in a non-backward type given above angle scattered light from a subject is injected direction is illuminated by the laser beam changed by the illumination unit, synchronized with the trigger unit associated with the imaging device An imaging drive unit that causes the imaging device to capture an image , and a light receiving device that is arranged apart from the ejection device and performs a self-triggered operation independent of the ejection device ;
Measuring system.   The measurement system according to claim 1, further comprising an arithmetic processing unit that determines a two-dimensional distribution of scattering coefficients based on an image signal captured by the imaging device.   The measurement system according to claim 2, wherein the arithmetic processing unit calculates a distribution of scattering coefficients by inverse analysis from predetermined initial information.   The illumination unit includes first and second polygon mirrors that rotate around orthogonal first and second rotation axes, respectively, and a reflection surface of the second polygon mirror that is disposed on the light exit side of the first polygon mirror. A first optical element for reducing the angle range of light rays incident on the second optical element, and a second optical element disposed on the light exit side of the second polygon mirror to proportionally restore the angle of the light rays before entering the first optical element. The measurement system according to any one of claims 1 to 3, further comprising an optical scanning unit having an optical element. The first optical element substantially matches the incident angles along a predetermined plane parallel to the second rotation axis of the light incident on the reflecting surface of the second polygon mirror;
The second optical element reflects, on the reflecting surface of the first polygon mirror, an emission angle of a light beam reflected by the reflecting surface of the second polygon mirror along another predetermined surface parallel to the second rotation axis. 5. The measurement system according to claim 4, wherein the measured light beam substantially coincides with an emission angle along the predetermined plane parallel to the second rotation axis. The imaging device has a photoelectric imaging tube for detecting an image including scattered light,
The measurement system according to any one of claims 1 to 5, wherein the trigger unit is provided along with the photoelectric imaging tube and sets a timing for extracting a signal from the imaging device. The imaging device includes a solid-state imaging device that is one of a CCD type imaging device and a CMOS type imaging device that detects an output of an image intensifier as the photoelectric imaging tube , and a timing signal output from the trigger unit The measurement system according to claim 6, wherein the solid-state imaging device is operated based on the above.

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