JP2013224915A - Laser radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser radar device that can quickly and accurately determine something diffusive such as a mist as noise when such the something diffusive is present in a detection area and thus, can quickly and accurately detect a detection target.SOLUTION: A laser radar device 1 is configured to include arrival position detection means and determination means. The arrival position detection means calculates a rotation angle of a deflection part upon generating a laser beam and a lapse time until reflection light corresponding to the laser beam is detected by detection means since the laser beam has been generated and detects an arrival position of the laser beam in external space. Also, when a plurality of arrival positions of the laser beam are detected by the arrival position detection means at any of a plurality of rotation angles in one period of the deflection part, the determination means determines that a detection result of an arrival position at a forward position with respect to an arrival position at the very back position at the plurality of rotation angles results from noise other than the detection target.

Description

  The present invention relates to a laser radar device.

  Conventionally, a system for monitoring an object that enters a monitoring area using a laser radar device has been provided. In this type of system, for example, a laser beam scanning unit and a light receiving unit are provided in the laser radar apparatus, and the laser beam scanning unit scans the space to be monitored. Reflected light from the object when the object is irradiated in space is detected by the light receiving unit, thereby grasping the presence of the object. Then, when the reflected light from the object is detected in this way, based on the irradiation direction of the laser light irradiated to the object and the time required from the generation of the laser light to the reception of the reflected light, When the position of the object is detected and the detected position is within a preset monitoring area, the object is determined as an intruder.

JP 2009-110069 A

  By the way, when a laser radar device as described above is installed to detect an object (such as an intruder) that has entered the monitoring area, the diffused object is sufficiently smaller than the detection target and should not be detected originally. When (such as fog or smoke) enters the monitoring area, or when such a diffusing material such as mist is generated in the monitoring area, these are detected, and each diffusing material is small. Since they appear together on the laser radar as one object, there is a possibility that the detection object may be erroneously determined to have entered. Such a problem is particularly a concern, for example, when a monitoring area is set outdoors that is susceptible to climatic conditions.

  For example, when a laser radar device is installed outdoors and an attempt is made to detect a person who enters the surveillance area set outdoors, fog may suddenly occur outdoors. There is a concern that it may occur within the monitoring area or enter the monitoring area from outside the monitoring area. When the fog enters the monitoring area in this way, the laser light emitted from the laser radar device is reflected by the fog (specifically, the small water droplets that make up the fog) in the monitoring area and appears as a large object. As a result, the fog will be mistaken for an intruder. Also, when trying to detect an intruder that has entered the surveillance area, for example, if fog is generated in a wide range to some extent in front of the intruder, the fog area is determined to be a person. There is also a risk that the exact location of the intruder will not be known.

  On the other hand, as a technique related to the above problem, a technique such as Patent Document 1 is provided. In the technique of this Patent Document 1, laser light scanning is periodically performed on a predetermined detection area, and discontinuous exceeding a predetermined level (exceeding the period, so-called time series) in the measurement period before, after, and after. When a change occurs, the distance information corresponding to the discontinuous information is removed as noise. In the technique of this Patent Document 1, the pulses (P20, P30) that appear when a part of the pulsed laser beam is reflected by raindrops are received light signals of reflected light in the measurement period before, after and in the same measurement direction. Based on the probabilistic idea that it does not normally appear in the waveform, specific distance data acquired in a certain measurement period in a certain measurement direction is acquired in the same measurement direction in the measurement periods before and after that measurement period. If the distance data is significantly different from the detected distance data, it is determined that the specific distance data is caused by noise such as raindrops or snow, and is removed as not being the distance data of the detection target (human body).

  However, in the method of Patent Document 1 described above, every time an object is detected in the monitoring area in order to determine whether the measured object is noise such as raindrops or a detection target (human body). At least two cycles or more of waveforms must be acquired and stored in real time, and further, processing for reading them out and comparing and judging them must be performed. In such a method, even if the reflected light from the object existing in the monitoring area can be confirmed on the apparatus side, processing required to determine whether the object is a detection target (human body) or noise Since the time is increased, it takes time until the determination result is obtained after the reflected light is confirmed on the apparatus side, and as a result, the rapid detection of the detection target (human body) is hindered. Become. Moreover, compared with the raindrop assumed in Patent Document 1, the mist is slow in movement and has a feature that it stays at the same position for a long time. Therefore, when the technique of Patent Document 1 is used in an environment where fog is generated, the fog may be continuously irradiated with a plurality of measurement cycles in the same measurement direction. Without being determined, it is erroneously determined as a detection target (human body). That is, according to the method of Patent Document 1, a diffused substance that stays in the same position for a long time, such as fog, cannot be accurately determined as noise.

  The present invention has been made in order to solve the above-described problems. When a diffused material such as fog exists in the detection area, the diffused material can be quickly and accurately determined as noise. Therefore, an object of the present invention is to provide a laser radar device capable of detecting a detection target quickly and accurately.

In order to achieve the above object, a laser radar device according to a first invention comprises:
Laser light generating means for generating laser light;
A deflection unit configured to deflect the laser beam generated by the laser beam generation unit; and a drive unit configured to rotate the deflection unit, and the deflection unit is rotated by the drive unit to irradiate the external space from the deflection unit. Scanning means for changing the direction of the laser beam,
Detecting means for detecting reflected light from the object when the laser light emitted by the scanning means is reflected by the object existing in the external space;
When the laser light is generated by the laser light generation means, the rotation angle of the deflection unit when the laser light is generated, and the reflected light corresponding to the laser light from the generation of the laser light is the detection means. An arrival position detecting means for detecting an arrival position of the laser beam in the external space based on the rotation angle and the elapsed time,
Determination means for determining that a detection object has been detected on the condition that the arrival position detected by the arrival position detection means is within a predetermined monitoring area;
With
The determination means detects a plurality of arrival positions of the laser light by the arrival position detection means at each irradiation position of the laser light when there are at a plurality of rotation angles in a rotation range of one cycle of the deflection unit. In this case, the detection result of the arrival position ahead of the last arrival position at the plurality of rotation angles is determined to be due to noise other than the detection target.

The laser radar device according to the second invention is
Laser light generating means for generating laser light;
The laser beam from the laser beam generating means is configured to be rotatable about a predetermined center axis, and at least vertically divided into a horizontal direction orthogonal to the center axis and a diagonally lower direction lower than the horizontal direction. A deflection unit that reflects each of them and a driving unit that rotates the deflection unit, and the upper and lower two laser beams irradiated to the external space from the deflection unit by rotating the deflection unit by the driving unit are the central axes. Scanning means for moving around,
First detection means for detecting, through the deflection unit, first reflected light generated by the reflection when the horizontal laser beam divided by the deflection unit is reflected by an object existing in the external space; ,
Second detection means for detecting second reflected light generated by the reflection when the laser beam in the obliquely downward direction divided by the deflection unit is reflected by the external space, via the deflection unit;
When the laser light is generated by the laser light generation means and the first reflected light corresponding to the laser light is detected by the first detection means, the deflection unit rotates when the laser light is generated. An angle and an elapsed time from the generation of the laser light to the detection of the first reflected light by the first detection unit are obtained, and the generation source of the first reflected light is determined based on the rotation angle and the elapsed time. First arrival position detection means for detecting a laser beam arrival position,
Determination means for determining that the detection target is detected on condition that the laser beam arrival position detected by the first arrival position detection means is within a predetermined monitoring area;
When the laser light is generated by the laser light generation means and the second reflected light corresponding to the laser light is detected by the second detection means, the deflection unit rotates when the laser light is generated. An angle and an elapsed time from the generation of the laser light until the second reflected light is detected by the second detection means are obtained, and the oblique downward direction in the external space is determined based on the rotation angle and the elapsed time. Second arrival position detecting means for detecting the arrival position of the laser beam;
When a plurality of arrival positions of the laser beam are detected by the second arrival position detection means at each rotation angle at any one of a plurality of rotation angles in the rotation range of one cycle of the deflection unit, these are continued. Noise detection means for determining that noise is generated at a plurality of rotation angles;
It is characterized by having.

  Since the diffusing material such as mist assumed in the invention of claim 1 has the characteristics that the particles are extremely fine and extremely small, there are particles such as mist on the path of one irradiated laser beam. However, not all of the laser light that passes through the path hits the particles, but some of the laser light continues to travel forward without hitting the particles. Therefore, as in claim 1, "when a plurality of arrival positions are detected at each irradiation position of the laser beam at a plurality of rotation angles in the rotation range of one period of the deflection unit" In each irradiation direction corresponding to the rotation angle, it is assumed that a part of the laser beam is irradiated to a diffusing material such as fog, and the remaining laser beam is irradiated to an object (background, etc.) behind the laser beam. When such a double detection result is obtained, it is determined that the detection result of the front arrival position at each of the plurality of rotation angles is due to noise other than the detection target. It becomes easy to remove. In particular, in the above method, based on the light reception results at a plurality of rotation angles in the rotation range of one cycle of the deflecting unit, it is determined whether the target object related to the light reception results is a detection target or noise such as fog. For example, when reflected light from an object is confirmed in a single scan (that is, one cycle scan), whether the object is a detection target or noise such as fog It becomes possible to discriminate based on the result of one scan. Accordingly, it is possible to detect the detection target more accurately while suppressing erroneous detection due to noise such as fog, and to effectively reduce the time required to distinguish between noise such as fog and the detection target. Thus, a device capable of speeding up detection can be realized.

In the invention of claim 2, the determination means detects the plurality of arrival positions of the laser light by the arrival position detection means in each irradiation direction of the laser light when the deflection unit is at a predetermined number of rotation angles in a continuous switching order. If detected, the detection result of the arrival position ahead of the rearmost arrival position at a predetermined number of rotation angles is determined to be due to noise other than the detection target.
Even when the end of the detection object is irradiated with laser light, two arrival positions may be detected as the arrival position of the laser light. In such a case, the laser light is applied to the end of the detection object. There is a high possibility that a plurality of arrival positions are detected only in one irradiated direction, and a possibility that a plurality of arrival positions are detected in a plurality of consecutive directions is low. Therefore, as described above, when a plurality of arrival positions of the laser beam are detected in each irradiation direction when the deflection unit is at a predetermined number of rotation angles in a continuous switching order, the end of the detection object is detected. A plurality of arrival positions are not detected because a plurality of arrival positions are detected due to the laser beam being irradiated to the part, but a part of the laser light hits a minute diffusive material such as fog in each irradiation direction. It can be said that there is a high possibility of being detected. Therefore, when such a detection result is obtained, if it is determined that the detection result of the front arrival position at a predetermined number of rotation angles is due to noise other than the detection target, it is caused by fog or the like with higher accuracy. It will be easier to remove noise.

According to a third aspect of the present invention, there is provided storage means for storing background data capable of specifying a background object position for each laser light irradiation direction within a scanning range of the laser light by the scanning means, and the determination means has a continuous deflection unit. In the respective irradiation directions of the laser light when the predetermined number of rotation angles are in the switching order, the arrival position detection means closes the position closer to the background object position in each irradiation direction determined by the background data as the arrival position of the laser light. On the condition that the distance position is detected and the far distance position farther than the near distance position is not detected, it is determined that the detection target is detected at the short distance position at the predetermined number of rotation angles.
When a diffusing material such as mist is present in the detection area of the external space, particles of the diffusing material (for example, minute water droplets) are extremely small, so a part of the laser light irradiated in a predetermined direction hits such particles. However, since the remaining portion of the laser beam is irradiated behind the particles, the arrival position of the laser beam in this irradiation direction is at least two positions. Therefore, as in the above configuration, in each irradiation direction, a short-distance position closer to the background object position in each irradiation direction determined by the background data is detected as a laser beam arrival position, and is farther than this short-distance position. When the long distance position is not detected as the arrival position of the laser beam, that is, when there is one laser beam arrival position in each irradiation direction, each laser beam arrival position detected in each irradiation direction (that is, a predetermined number) It is highly possible that each short distance position at the rotation angle is not the position of the minute particles as described above but the position of the detection target. Therefore, if it is determined that the detection target is detected at these short-distance positions on the condition that such a detection result is obtained, the detection target can be detected more accurately.

According to a fourth aspect of the present invention, there is provided storage means for storing background data capable of specifying a background object position for each laser light irradiation direction within a scanning range of the laser light by the scanning means, and the deflection unit at any of a plurality of rotation angles. When the first arrival position and the second arrival position behind the first arrival position are detected by the arrival position detection means in each irradiation direction of the laser beam, the reflection from the first arrival position in each irradiation direction Reflected light from the second arrival position in each irradiation direction by a correction formula or correction table that can set a correction value in each irradiation direction based on the light reception waveform of light and the light reception waveform of reflected light from the second arrival position. Correction means for correcting the received light waveform so as to compensate for the attenuation based on the received light waveform at the first arrival position in each irradiation direction.
Then, the determination means determines the second arrival position based on the correction result obtained by correcting the received light waveform from the second arrival position in each irradiation direction by the correction means and the background object position in each irradiation direction determined by the background data. It is determined whether or not the object existing in the background is the background, and when it is determined that the object is not the background, it is determined that the detection target is detected at the second arrival positions at a plurality of rotation angles.
When a diffusing material such as mist exists in the detection area of the external space, a part of the laser light irradiated in a predetermined direction hits the particle of the diffusing material, and the remaining laser light irradiates the background object behind When this is done, the amount of laser light applied to the background object will be smaller than normal (when irradiated directly without irradiating a diffusing material such as fog), and the received light waveform of the reflected light from the background object will be This greatly changes from the normal light reception waveform that was originally planned. If the light reception waveform from the background object changes in this way, the calculated position of the background object may deviate from the original position determined by the background data.
On the other hand, when the correction means is provided as described above and two positions (first arrival position and second arrival position) are detected as the laser light arrival positions in each irradiation direction, the second arrival in each irradiation direction is detected. If the received light waveform of the reflected light from the position is corrected so as to compensate for the attenuation based on the received light waveform at the first arrival position in each irradiation direction, normal time at each second arrival position (when laser light is directly irradiated) It becomes easy to guess the waveform contents of the above, and it becomes possible to more accurately determine whether or not the second arrival position is the background object position.

In the invention of claim 5, the deflecting unit reflects the laser beam from the laser beam generating means in the horizontal direction and the obliquely lower direction that is lower than the horizontal direction, and reflects the laser beam. By rotating the, it is possible to scan in the horizontal direction and scan in the diagonally downward direction.
And about one laser beam irradiated to a horizontal direction, the reflected light (1st reflected light) which arises when the said laser beam reflects with the object which exists in external space is detected by a 1st detection means, 1st The arrival position detection means can detect the laser light arrival position that is the generation source of the first reflected light based on the detection result of the first detection means. According to this configuration, it is possible to detect an object by horizontal scanning, and it is possible to specify at which position in the horizontal direction an object is present.
On the other hand, with respect to the other laser beam irradiated obliquely downward with the deflection unit as a base point, noise such as fog can be determined based on the same idea as in the first aspect. In the configuration of claim 5, when a plurality of reaching positions are detected by laser beams obliquely downward when there are a plurality of continuous rotation angles within one cycle of the deflecting unit, each of the plurality of rotation angles is detected. In this case, it is assumed that a part of the laser beam obliquely downward is irradiated on a diffusing material such as fog, and the remaining laser beam is irradiated on an object (ground, floor surface, etc.) behind it. In this configuration, when such double detection results are obtained at a plurality of continuous rotation angles, it is determined that noise is generated at the plurality of rotation angles. It is possible to deal with the noise at a more accurate timing, assuming that the noise due to the occurrence is generated. In addition, when the above double detection result is obtained at “a plurality of continuous rotation angles”, a part of the laser beam is irradiated to the end of the detection target, and the remaining laser beam is an object behind the detection target. Since there is a high possibility that this is not the case, the problem of determining a proper detection target as noise is unlikely to occur.
In particular, in the above method, it is possible to determine whether or not noise such as fog is generated based on the light reception result within one cycle without rotating the deflection unit many times, so that noise such as fog is generated. It is possible to effectively reduce the time required to determine whether or not the detection is performed and speed up detection.
Further, in this configuration, the laser beam is divided by the deflection unit so that one laser beam (laser beam mainly used for noise determination) is irradiated obliquely downward, and the obliquely downward laser beam is an optical path. When the whole reaches a certain distance without being obstructed, the object inevitably reaches an object such as the ground or floor. Therefore, for example, “a noise object such as fog is irradiated with a part of the laser beam, but the remaining laser beam does not hit the object far away (for example, far enough that the reflected light cannot be detected). Noise detection omission such as “a double detection result cannot be obtained at the rotation angle” can be prevented, and the detection accuracy of noise such as fog can be significantly improved.

In the invention of claim 6, when it is determined by the noise detection means that noise is generated at a plurality of rotation angles, the first arrival position detection means detects the laser beam at any one of the plurality of rotation angles. Even when the arrival position is detected, it is not determined that the detection target has been detected.
If noise is detected on the basis of laser light obliquely downward at any rotation angle, the cause of noise, such as fog, at that rotation angle is not only object detection in the diagonally downward direction, but also object detection in the horizontal direction. It is highly possible that the Therefore, when it is determined that noise is generated at each rotation angle based on each laser beam irradiated obliquely downward at a plurality of successive rotation angles, the laser beam reaches by horizontal irradiation at each rotation angle. If it is determined that the detection target is not detected even if the position is detected, the risk of erroneously detecting noise such as fog as a detection target can be reduced as much as possible.

In the invention of claim 7, the laser radar device is installed so that the central axis is in a direction perpendicular to the ground or floor surface at a predetermined height from the ground or floor surface. The position where the obliquely downward laser beam reaches the ground or the floor at each rotation angle of the deflecting unit is configured to be outside the monitoring area at each rotation angle.
According to this configuration, the horizontal range in which noise can be detected at each rotation angle (that is, the horizontal range from the device to the ground where the laser beam obliquely downward reaches the base point) is the monitoring area. Since the horizontal range is included, it is possible to detect noise in a manner that covers the monitoring area at each rotation angle. Therefore, noise such as fog generated in the monitoring area can be detected more reliably while suppressing detection omission.

In the invention of claim 8, since the deflecting portion can be used for both light projection and light reception, the number of parts can be reduced and the size can be reduced as compared with a configuration in which a light projecting rotary mirror and a light receiving rotary mirror are provided separately. Furthermore, since the deflecting portion can be used as a concave mirror to collect reflected light, it is not necessary to arrange a large condensing lens or the like, and it is easy to further reduce the size.
Further, the concave mirror is configured to reflect the light entering the direction of a predetermined angle with respect to the concave mirror while collecting the light toward the condensing point on the central axis, and condensing toward the condensing point. Of the received light, the light reflected by the reflecting surface of the mirror is received by the light receiving region of the detecting means. In this configuration, when the laser light (projection laser) is reflected by an object at a short distance, the reflected light is easily guided to the vicinity of the through-hole formed in the mirror when returning to the concave mirror. In other words, the ratio of the light that escapes through the through-hole in the reflected light (reflected light from the object) that enters the concave mirror increases, so the amount of light received by the detection means is effective for the detection of short-distance objects that are likely to saturate. Can be suppressed.
Such a feature is very advantageous when it is desired to discriminate fine particles such as fog by detecting a plurality of received light pulses at a certain rotation angle as in the present invention. For example, when a mist is present at a short distance, when the laser light is reflected by the mist particles and the reflected light is received by the detection means, the received light level easily reaches a saturation level (waveform P1 in FIG. 11A). Example). Once the amount of received light reaches the saturation level in this way, it takes time until the next reflected light can be detected (that is, until the detected amount of received light decreases to a low level). Therefore, when there is an object immediately behind the fog particles, the light reception pulse of the reflected light from the object may be drowned out by the light reception pulses from the fog particles (the waveform P2 in FIG. 11A). Example). However, in the invention of claim 8, since the amount of light received by the detecting means can be effectively suppressed as described above for the reflected light from the object at a short distance, such a problem can be solved. . For example, the waveform P1 ′ in FIG. 11B shows a waveform when the reflected light from the fog particles at a short distance is received with a considerably reduced light receiving level, and thus the light receiving level can be suppressed. For example, even when there is an object immediately behind the fog particles, the light reception waveform P2 from the object and the light reception waveform P1 ′ from the fog particles can be distinguished, and the detection omission of the object is prevented. Can do.
On the other hand, when laser light (projection laser) is reflected by an object at a long distance, when the reflected light returns to the concave mirror, it becomes easy to be guided from the concave mirror to the entire mirror. In other words, the ratio of the light that escapes through the through hole out of the reflected light entering the concave mirror (reflected light from the object) is smaller than in the case of a short distance, so the loss in the light receiving path can be suppressed, and the amount of received light can be reduced. The detection sensitivity of reflected light from a long distance that tends to be small can be reliably increased.

According to the ninth aspect of the present invention, the concave mirror includes a planar reflection portion having a flat planar reflection surface disposed at an incident position of the laser beam from the laser beam generating means, and a concave reflection having a curved concave reflection surface. Light that enters the direction of a predetermined angle (angle of the light projecting laser) with respect to the concave mirror. Is reflected while the concave reflecting portion condenses toward the condensing point on the central axis.
In this way, by providing a plane reflecting portion at the starting position of the projection laser irradiation (reflection position at the concave mirror), the laser light reflected by the concave mirror becomes difficult to diffuse, and the laser beam is increased by increasing the energy density of the laser light. You can fly farther away. However, in this configuration, since the energy density at a short distance is further increased, the above-described problem in the case where fog is present at a short distance (problem of detection of a rear object due to saturation of the amount of received light) is more remarkable. Become. Therefore, it is more effective to apply the above-described characteristic configuration to such a configuration to suppress the detection sensitivity of reflected light from a short distance and increase the detection sensitivity of reflected light from a long distance.

FIG. 1 is a cross-sectional view schematically illustrating a laser radar device according to a first embodiment of the invention. FIG. 2 is an explanatory diagram for explaining how the laser radar device of FIG. 1 is installed outdoors and detected. FIG. 3A is a flowchart illustrating the flow of detection processing performed in the laser radar apparatus of FIG. 1, and FIG. 3B is a flowchart illustrating the flow of initial processing in the detection processing. FIG. 3C is a flowchart illustrating the flow of the distance measurement process in the detection process. FIG. 4 is a flowchart illustrating the flow of the noise discrimination process in the distance measurement process of FIG. FIG. 5 is a graph showing the distance data of the background object obtained by the initial setting process, and shows the distance from the laser radar device to the background object in the irradiation direction at each rotation position (rotation angle). FIG. 6A is a graph showing a light reception waveform of a photodiode when laser light is reflected by a single object in a certain irradiation direction, and FIG. It is a graph which shows the light reception waveform in the photodiode when it reflects with one object. FIG. 7 is an explanatory diagram for explaining attenuation of reflected light from a rear arrival position. FIG. 8 is an explanatory diagram for explaining a correction table for correcting the received light waveform at the rear arrival position. FIG. 9 is an explanatory diagram conceptually illustrating a state of light reception when detecting a short-distance object in the laser radar device according to the first embodiment. FIG. 10 is an explanatory diagram conceptually illustrating a state of light reception when a long-distance object is detected in the laser radar device according to the first embodiment. FIG. 11A is an explanatory diagram illustrating an example of a received light waveform when the received light waveform from a short-range fog particle is saturated and the waveform of the object behind cannot be read, and FIG. It is explanatory drawing explaining the example of the light reception waveform in case the light reception amount from the mist particle | grain is suppressed in the waveform of FIG. 11 (A). FIG. 12 is a perspective view schematically illustrating a deflection unit used in the laser radar apparatus according to the modification of the first embodiment. FIG. 13 is a cross-sectional view schematically illustrating a laser radar device according to the second embodiment of the invention. FIG. 14 is a perspective view schematically showing a deflection unit used in the laser radar apparatus of FIG. FIG. 15 is a schematic cross-sectional view schematically and partially showing a cut surface obtained by cutting the concave mirror used in the laser radar apparatus of FIG. 13 in the plane direction passing through the central axis. FIG. 16 is an explanatory diagram conceptually illustrating a state in which a detection state when the laser radar device of FIG. 13 is installed outdoors to detect an object is viewed from the side. FIG. 17 is an explanatory diagram conceptually illustrating a state in which a detection state when the laser radar device of FIG. 13 is installed outdoors to perform object detection is viewed from above.

[First embodiment]
Hereinafter, a first embodiment of a laser measuring device according to the present invention will be described with reference to the drawings.
(Overview of laser radar equipment)
First, the outline of the laser radar device 1 will be described with reference to FIG.
FIG. 1 is a cross-sectional view schematically illustrating the overall configuration of the laser radar device 1 according to the first embodiment. FIG. 2 is an explanatory diagram for explaining how the laser radar device of FIG. 1 is installed outdoors and detected. FIG. 1 schematically shows a configuration in which the laser radar device 1 is cut along a predetermined cut surface (a cut surface passing through the center axis 42a and the light receiving position of the photodiode 20) along the rotation center axis 42a of the concave mirror 41. Yes. In the following description, the cross section of the transmission plate is shown in white.

  As shown in FIG. 2, the laser radar apparatus 1 includes a laser diode 10 and a photodiode 20 that receives reflected light L2 from the detection object, and the distance and direction to the detection object existing in the scanning area outside the apparatus. It is comprised as an apparatus which detects.

  The laser diode 10 corresponds to an example of “laser light generation means”, receives a pulse current from a drive circuit (not shown) under the control of the control circuit 70, and receives a pulse laser light (laser light L1) corresponding to the pulse current. ) Is emitted intermittently. In the present embodiment, laser light from the laser diode 10 to an object (not shown) outside the apparatus is conceptually indicated by reference numeral L1, and reflected light from the object outside the apparatus to the photodiode 20 is indicated. This is conceptually indicated by reference numeral L2.

The photodiode 20 is composed of, for example, an avalanche photodiode. The photodiode 20 has a light receiving area for receiving light, and is configured to detect light incident on the light receiving area. Laser light L1 is generated from the laser diode 10, and the laser light L1 is emitted from the outside of the apparatus. When the light is reflected by a detection object (not shown) existing in the light, the reflected light L2 (specifically, the light guided to the light receiving region by the concave mirror 41 and the mirror 30 in the reflected light L2) is received and electrically received. It functions to convert to a signal. Note that the reflected light from the detection object is configured to be received by the concave mirror 41 in a predetermined area in the vertical direction. In FIG. 2, the lines L2a, L2a, L2b, The reflected light L2 in the region between L2b is reflected by the concave mirror 41.
In the present embodiment, the photodiode 20 corresponds to an example of a “detection unit”, and detects reflected light from the object when laser light irradiated by a scanning unit described later is reflected by an object existing in the external space. To function.

  A lens 60 is provided on the optical axis of the laser light L1 emitted from the laser diode 10. The lens 60 is configured as a collimating lens, and condenses the laser light L1 generated and diffused by the laser diode 10 and converts it into substantially parallel light.

  A mirror 30 is provided in the vicinity of the optical path of the laser light L1 that has passed through the lens 60. The mirror 30 includes a reflective surface 31 that is inclined at a predetermined angle (for example, 45 °) with respect to the optical axis of the laser light L1, and a through hole 32 that intersects the reflective surface 31. In the present embodiment, the direction of the central axis 42a that is the rotation center of the concave mirror 41 is the vertical direction, and the direction orthogonal to the vertical direction is the horizontal direction, and the reflecting surface 31 of the mirror 30 is at a predetermined angle with respect to the vertical direction. A through hole 32 that is inclined at 45 ° (for example, 45 °) and communicates in the vertical direction so as to penetrate the reflecting surface 31 downward from above is formed. The mirror 30 configured in this manner allows the laser beam L1 emitted from the laser diode 10 and passing in the direction of the central axis 42a to pass through the through hole 32 to the concave mirror 41 side, while reflecting from a detection object outside the apparatus. The light L2 (more specifically, reflected light reflected by the concave mirror 41) is reflected by the reflecting surface 31 and functions to guide to the photodiode 20 side.

  Further, a rotary reflection mechanism 40 is provided on the optical axis of the laser light L1 that passes through the mirror 30. The rotary reflection mechanism 40 includes a concave mirror 41 configured to be rotatable, a shaft portion 42 connected to the concave mirror 41, and a bearing (not shown) that rotatably supports the shaft portion 42. The concave mirror 41 reflects the laser light L1 from the laser diode 10 toward the space, and the concave mirror 41 functions to deflect the reflected light L2 from the detection object outside the apparatus toward the photodiode 20. ing.

  The concave mirror 41 includes a concave reflecting surface 41a disposed on the optical axis of the laser light L1 that has passed through the mirror 30. The reflecting surface 41a of the concave mirror 41 is configured as a paraboloid, for example, and reflects the reflected light L2 in a predetermined region (region between L2a and L2b) incident in parallel along the horizontal direction upward. The shape is adjusted so that the focal position of the reflected light L2 that is condensed and condensed is on the central axis 42a.

  The concave mirror 41 is disposed so as to be rotatable about a central axis 42a extending in the vertical direction. The direction of the central axis 42a, which is the rotation center of the concave mirror 41, substantially coincides with the direction of the laser light L1 that passes through the mirror 30 and enters the concave mirror 41, and the incident position where the laser light L1 enters the concave mirror 41 is The position is near the position P1 on the central axis 42a.

  In the present embodiment, the portion near the position P1 on the reflecting surface 41a of the concave mirror 41 is inclined at an angle of approximately 45 ° with respect to the vertical direction (the direction of the laser light L1 incident on the reflecting surface 41a). The laser beam L1 reflected by the reflecting surface 41a of the concave mirror 41 is irradiated in the horizontal direction. Further, since the concave mirror 41 rotates around the central axis 42a in the direction coinciding with the direction of the incident laser beam L1, the incident angle of the laser beam L1 is always about 45 ° regardless of the rotational position (rotation angle) of the concave mirror 41. And the direction of the laser beam L1 from the position P1 is constantly horizontal (the direction orthogonal to the central axis 42a). In the present embodiment, the direction of the central axis 42a is the vertical direction (vertical direction, vertical direction), and the plane direction orthogonal to the central axis 42a is the horizontal direction.

  Further, the laser radar device 1 is provided with a motor 50 that drives the rotary reflection mechanism 40. The motor 50 rotates the shaft portion 42 to rotate the concave mirror 41 connected to the shaft portion 42. As a specific configuration of the motor 50, various motors such as a DC motor, an AC motor, and a step motor can be used.

  In this configuration, the concave mirror 41 corresponds to an example of a “deflecting unit” and functions to deflect the laser light generated by the laser light generating means. Also. The motor 50 corresponds to an example of a “drive unit” and functions to rotate the deflection unit. Further, the rotary reflection mechanism 40 and the motor 50 correspond to an example of “scanning unit”, and function to change the direction of the laser light irradiated from the deflection unit to the external space by rotating the deflection unit by the driving unit. .

  In the present embodiment, as shown in FIG. 1, a rotation angle sensor 52 that detects the rotation angle position of the shaft portion 42 of the motor 50 (that is, the rotation angle position of the concave mirror 41) is provided. As the rotation angle sensor 52, various known sensors can be used as long as they can detect the rotation angle position of the shaft portion 42, such as a rotary encoder.

  Further, in the laser radar device 1 according to the present embodiment, the laser diode 10, the photodiode 20, the mirror 30, the lens 60, the rotary reflection mechanism 40, the motor 50, and the like are housed in the case 3, and dust and shock protection are achieved. It has been. The case 3 includes a main case portion 4 and a transmission plate 5 and is configured in a box shape as a whole. The main case portion 4 is configured such that the upper wall portion 4a and the lower wall portion 4b are vertically opposed to each other, the peripheral wall portion 4c is configured as an outer peripheral wall on the upper side, and the space between the peripheral wall portion 4c and the lower wall portion 4b. The window 4e is opened so that light can be guided. The window portion 4e is a portion opened so as to allow light to enter and exit from the main case portion 4, is formed over a predetermined area in the circumferential direction below the case 3 and around the concave mirror 41, and is predetermined in the vertical direction. It is provided with the structure which opens an area | region. And the permeation | transmission board 5 which consists of a transparent resin plate, a glass plate, etc. is arrange | positioned so that the window part 4e of this open form may be obstruct | occluded.

  In the laser radar device 1 configured as described above, if the rotation angle θ of the concave mirror 41 (a rotation angle from a predetermined reference rotation position (for example, a position where the rotary encoder indicates the origin)) is determined, the laser beam L1 from the device is determined. The projection direction is specified. Therefore, if the laser radar device 1 is installed in a desired inclination state (for example, a state in which the scanning direction of the laser light L1 is always perpendicular to the vertical direction), the photodiode 20 reflects from the object. By detecting the rotation angle of the concave mirror 41 when the light L2 is received by the rotation angle sensor 52, the orientation of the object can be accurately detected. Whether or not the photodiode 20 receives the reflected light from the object can be determined by whether or not the amount of light received by the photodiode 20 (that is, the output from the photodiode 20) exceeds a threshold, “When the reflected light exceeding the threshold value is received by the photodiode 20” is “when the reflected light L2 from the object is received”.

  Further, if the time T from when the laser light L1 (pulse laser light) is generated by the laser diode 10 until the reflected light L2 corresponding to the laser light L1 is detected by the photodiode 20 is detected, this time T And the speed of light, the length of the optical path from the generation of the laser light L1 to the reception of the reflected light L2 can be calculated, and the distance from the predetermined reference position (for example, position P1) of the laser radar device 1 to the detected object L can also be accurately obtained. That is, it is possible to accurately detect the distance and the direction from the laser radar device 1 to the detection object.

  In the present embodiment, the rotation angle sensor 52 and the control circuit 70 correspond to an example of “arrival position detection means”. When laser light is generated by the laser diode 10 (laser light generation means), the laser light The angle of rotation of the concave mirror 41 (deflecting unit) when this occurs, and the elapsed time from the generation of the laser light until the reflected light corresponding to the laser light is detected by the photodiode 20 (detection means), Based on these rotation angles and elapsed time, it functions to detect the arrival position of the laser beam in the external space.

(Detection process)
Next, detection processing performed by the laser radar device will be described.
FIG. 3A is a flowchart illustrating the flow of detection processing performed in the laser radar apparatus of FIG. 1, and FIG. 3B is a flowchart illustrating the flow of initial processing in the detection processing. FIG. 3C is a flowchart illustrating the flow of the distance measurement process in the detection process. FIG. 4 is a flowchart illustrating the flow of the noise discrimination process in the distance measurement process of FIG. FIG. 5 is a graph showing the distance data of the background object obtained by the initial setting process, and shows the distance from the laser radar device to the background object in the irradiation direction at each rotation position (each rotation angle). . FIG. 6A is a graph showing a light reception waveform of a photodiode when laser light is reflected by a single object in a certain irradiation direction, and FIG. It is a graph which shows the light reception waveform in the photodiode when it reflects with one object. FIG. 7 is an explanatory diagram for explaining attenuation of reflected light from a rear arrival position. FIG. 8 is an explanatory diagram for explaining a correction table for correcting the received light waveform at the rear arrival position.

In the present embodiment, detection processing is performed according to the flow shown in FIG. 3A when a predetermined start condition is satisfied (for example, when power is turned on or when a predetermined operation or the like is performed on an operation unit (not shown)).
In this detection process, the initial setting process (S1) is first performed, and then the distance measurement process (S2) is repeated.

  The initial setting process of S1 has a flow as shown in FIG. 3B. First, an initial value setting process is performed (S10). In the initial value setting process, various settings such as setting of the rotation reference position of the concave mirror 41 are performed. Here, the case where the direction of the arrow F1 shown in FIG. 2 is the reference direction of the rotation angle 0 °, the direction of the arrow F2 is the direction of 180 °, and the range of 0 ° to 180 ° is the detection angle range will be described. To do.

  After the process of S10, a process for setting a ranging area (monitoring area) is performed (S11). In this process, scanning with laser light is performed in a predetermined angle range (angle range of 0 ° to 180 ° shown in FIG. 2), and the arrival position of the laser light is detected at each rotation position (each rotation angle) in this angle range. To do. Specifically, the concave mirror 41 is rotationally driven and the pulsed laser light L1 is sequentially emitted from the laser diode 10 at each rotational angle to scan the laser light L1. The rotational speed of the concave mirror 41 and the emission time interval of the pulse laser beam L1 can be set variously. For example, the timing at which the pulse laser beam L1 is emitted every time the concave mirror 41 rotates by 0.5 °. Can be scanned. Further, it is desirable that the laser beam scan in S11 is performed after confirming that no object is present in the area to be monitored. In this case, each rotational position when each pulse laser beam L1 is emitted. The pulsed laser light L1 projected from the concave mirror 41 at each rotation angle is reflected by the background object, and a part of this reflected light is incident on the concave mirror 41 again. Therefore, the distance from the laser radar device 1 to the background object when the laser beam is irradiated at each rotational position can be calculated.

  In the process of S11, as shown in FIG. 5, the arrival position (distance value to the arrival position) of the laser beam at each rotation position (each rotation angle) in the detection angle range (here, 0 ° to 180 °) is acquired. it can. The distance value to the arrival position at each rotational position detected in this process is the limit position where laser light can be emitted at each rotational position, and the position of the background object in the laser light irradiation direction at each rotational position is It is shown. In this way, data indicating the position of the background object in the laser light irradiation direction at each rotational position in the detection angle range is obtained, and in the embodiment, the inner area divided by the background object in this way is the distance measurement area. Set as (monitoring area). In FIG. 2, background objects are indicated by reference signs A <b> 1 to A <b> 5, and inner distance measurement area areas (monitoring areas) divided by the background objects are indicated by hatching.

  The distance data to the background object at each rotation angle as shown in FIG. 5 corresponds to an example of “background data”, and the position of the background object for each laser light irradiation direction in the laser light scanning range by the scanning unit is shown. It works to identify. The storage unit 80 corresponds to an example of a “storage unit” that stores such background data.

  After the initial setting process shown in FIG. 3B, a distance measurement process is performed (S2). In this distance measurement process, the concave mirror 41 is driven to rotate, and the pulse laser beam L1 is sequentially emitted from the laser diode 10 at each rotation angle to scan the laser beam L1. Then, for example, a received light waveform is acquired for each rotation angle in one cycle of the detection angle range (here, 0 ° to 180 °), and the arrival position (distance value) of the laser beam in the irradiation direction at each rotation angle is calculated. (S20). Here again, at each rotation angle, a time T1 from the projection of the pulse laser beam L1 to the light reception (reception of reflected light exceeding the threshold) is detected, and the laser beam arrival position is detected based on this time T1 and the speed of light. Calculate the distance value. In this process as well, the rotational speed of the concave mirror 41 and the emission time interval of the pulsed laser light L1 can be set variously. For example, as in the initial setting process, a pulse is generated every time the concave mirror 41 rotates by 0.5 °. Scanning can be performed at a timing such that the laser beam L1 is emitted. Then, after calculating the distance value at each rotation angle in the detection angle range (0 ° to 180 °), noise discrimination processing is performed (S21).

The noise determination process of S21 is performed according to the flow as shown in FIG. 4, for example.
First, in the detection angle range (0 ° to 180 °), a group whose distance value to the reaching position is approximated at a plurality of continuous rotation angles is detected. Specifically, in the detection angle range (0 ° to 180 °), when focusing on two consecutive rotation angles, the difference in distance value to the reaching position at these rotation angles is within a predetermined range. The respective arrival positions of these rotation angles are set to the same group, and when the difference in distance value to the arrival position at these rotation angles is not within a predetermined range, the arrival positions of these rotation angles are set to different groups. Perform grouping.

  After S30, it is determined whether or not a plurality of arrival positions are detected at any rotation angle (S31). In the case where only a single object is irradiated with laser light in the laser light irradiation direction at a certain rotation angle, the light reception waveform at the rotation angle has a light reception amount exceeding the threshold as shown in FIG. Only one mountain appears, and in such a case, it can be determined that a single arrival position is detected at the rotation angle. On the other hand, when a plurality of objects are irradiated with laser light in the laser light irradiation direction at a certain rotation angle, the light reception waveform at the rotation angle has a light reception amount exceeding the threshold as shown in FIG. A plurality of mountains appear, and in such a case, it can be determined that a plurality of arrival positions are detected at the rotation angle. In S30, it is determined whether or not a rotation angle at which a plurality of arrival positions are detected exists in the detection angle range (0 ° to 180 °). If there is no rotation angle at which a plurality of arrival positions are detected in the detection angle range (0 ° to 180 °), the process proceeds to Yes in S31, and the position of the detection target object based on the received light waveform at each rotation angle. Is identified. The object detection method in this case is the same as the conventional method, and whether or not an object has been detected in the distance measurement area (that is, the monitoring area set in S11 of FIG. 3B) based on the distance value calculated in S20. If it can be determined that the object has been detected, the position is specified using the object as a detection target.

  On the other hand, if a plurality of arrival positions are detected at any rotation angle, the process proceeds to No in S31, and it is determined whether or not the detection pattern of the plurality of arrival positions corresponds to the pattern of the detection object. (S33). In the process of S33, on condition that there are a plurality of rotation angles at which a plurality of arrival positions are detected (hereinafter also referred to as a plurality of position detection rotation angles), each of the plurality of position detection rotation angles is detected by another plurality of positions. When the rotation angle is within a predetermined angle difference, each of the plurality of position detection rotation angles is determined as a rotation angle where noise is generated (hereinafter also referred to as noise generation rotation angle). Conversely, if any of the multi-position detection rotation angles is not within a predetermined angle difference from the other multi-position detection rotation angles, any of the multi-position detection rotation angles can be determined as a noise generation rotation angle. First, it is determined as the pattern of the detection object.

  The “predetermined angle difference” may be a minimum irradiation step (resolution) of sequentially irradiated laser light, or may be about several times (for example, 2 to 3 times) the minimum irradiation step. . The minimum irradiation step corresponds to an angular difference between a certain laser beam irradiation direction when the concave mirror 41 is driven in a steady state and a next laser beam irradiation direction.

  If it is determined in S33 that the pattern of the detection target exists, the process proceeds to Yes in S33, and the pattern of the detection target (multiple position detection rotation not within a predetermined angle difference from other multiple position detection rotation angles) As for (angle), the frontmost arrival position is specified as the position of the detection target. Further, when the process proceeds to Yes in S33, if there is a noise generation rotation angle, the arrival position before the last arrival position is determined as noise for the noise generation rotation angle, and the last arrival position is determined. Are identified as non-noise objects (detection objects or background objects). This noise generation rotation angle is processed in the same manner as S35 and S36. In addition to the rotation angle at which a single arrival position is detected (single arrival position detection rotation angle) other than the pattern of the detection target and the noise generation rotation angle, the detected arrival position is within the monitoring area. In this case, the arrival position is specified as the position of the detection object, and when the detected arrival position corresponds to the position of the background object, the arrival position is specified as the position of the background object.

  If the pattern of the detection target object does not exist, the process proceeds to No in S33, and the arrival position before the last arrival position at each noise generation rotation angle is determined as noise, and the last arrival position is determined as noise. It is determined that there is no object (detection object or background object) (S35). Then, after S35, a correction process and a position specifying process are performed for the last arrival position at each noise generation rotation angle (S36).

In the process of S36, the received light waveform obtained at each noise generation rotation angle (that is, as shown in FIG. 6B), the waveform corresponding to the first arrival position and the second arrival behind this first arrival position. In the received light waveform including the waveform corresponding to the position), the waveform obtained by the reflected light from the last arrival position (second arrival position) is corrected, and based on this correction result, the last arrival position It is determined whether or not is a background position. As this correction method, various methods can be adopted. For example, as shown in FIG. 7, the waveform width Wa at the threshold value is obtained in the waveform Pa (waveform which becomes a peak) at the end position, and stored in advance. By referring to the correction table, the correction amount Δ from the detection position (first timing exceeding the threshold in the waveform Pa) can be calculated, and the detection position can be corrected.

  In this case, as shown in FIG. 8, a correction table is prepared in which candidate values for the waveform width at the threshold and the correction amounts corresponding to the candidate values are associated with each other. A position that is on the front side by the correction amount (value obtained from the correction table) can be determined as a normal position. In other words, it is assumed that at the last arrival position, the waveform is attenuated by a predetermined amount D as compared with the originally assumed waveform Pb, and the waveform width at the threshold is also shorter than the original waveform width Wb. Therefore, the detection position is set to the front side by the amount retracted due to this attenuation. When the regular position determined in this way corresponds to the background position, it is assumed that the detection target is not detected at the rotational position. On the other hand, when the determined regular position does not correspond to the background position, the corrected position is determined as the position of the detection object at the rotation position.

  In addition, when progressing to No in S33, about the rotation angle (single arrival position detection rotation angle) from which the single arrival position was detected other than the noise generation rotation angle, the detected arrival position is within the monitoring area. In some cases, the arrival position is specified as the position of the detection target, and when the detected arrival position corresponds to the position of the background object, the arrival position is specified as the position of the background object.

  In this example, the control circuit 70 that performs the processing of FIGS. 3 and 4 corresponds to an example of “correction unit”, and the correction formula or correction table that can set the correction value in each irradiation direction is used to change the first in each irradiation direction. It functions to correct the light reception waveform of the reflected light from the two arrival positions so as to compensate for the attenuation based on the light reception waveform of the first arrival position in each irradiation direction. In the above example, the correction is performed using the correction table. However, the relationship between the waveform width and the correction amount is such that the correction amount increases as the waveform width decreases. It may be expressed by (a linear expression such as a proportional expression or a quadratic expression), and the correction amount may be determined by this correction expression.

  In the present embodiment, the control circuit 70 corresponds to an example of “determination means”, and the detection target is detected on the condition that the arrival position detected by the arrival position detection means is within a predetermined monitoring area. It functions to determine that it has been done. Further, the determination means is configured to detect a plurality of arrivals of the laser light by the arrival position detection means at each irradiation position of the laser light when the concave mirror 41 (deflection unit) is at any of a plurality of rotation angles in the rotation range of one cycle. When the position is detected, it is determined that the detection result of the arrival position ahead of the last arrival position at the plurality of rotation angles is due to noise other than the detection target.

(Main effects of the first embodiment)
In the present embodiment, “when a plurality of arrival positions of the laser beam are detected by the arrival position detecting means at each irradiation position of the laser beam when the concave mirror 41 is at any one of a plurality of rotation angles in the rotation range of one cycle. In other words, in each irradiation direction corresponding to each of the plurality of rotation angles, a part of the laser beam is irradiated to a diffusing material such as fog, and the remaining laser beam is applied to an object (background, etc.) behind it. It is assumed that it was irradiated. Therefore, when such a detection result is obtained, if it is determined that the detection result of the front arrival position at each of the plurality of rotation angles is due to noise other than the detection target, noise caused by fog or the like is removed. It becomes easy. In particular, in the above method, based on the light reception results at a plurality of rotation angles in the rotation range of the concave mirror 41 in one cycle, it is determined whether the target object related to the light reception result is a detection target or noise such as fog. For example, when reflected light from an object is confirmed in a single scan (that is, one cycle scan), whether the object is a detection target or noise such as fog It becomes possible to discriminate based on the result of one scan. Accordingly, it is possible to detect the detection target more accurately while suppressing erroneous detection due to noise such as fog, and to effectively reduce the time required to distinguish between noise such as fog and the detection target. Thus, a device capable of speeding up detection can be realized.

In the above configuration, when each multi-position detection rotation angle is within a predetermined angle difference from other multi-position detection rotation angles, each multi-position detection rotation angle is a rotation angle (hereinafter referred to as noise generation). In particular, the laser beam is detected by the arrival position detection means in each irradiation direction of the laser light when the concave mirror 41 (deflection unit) is at two or more rotation angles in a continuous switching order. When a plurality of arrival positions of light are detected, it is determined that the detection result of the arrival position ahead of the last arrival position is due to noise other than the detection target at each of the two or more consecutive rotation angles. Yes.
Even when the end of the detection object is irradiated with laser light, two arrival positions may be detected as the arrival position of the laser light. In such a case, the laser light is applied to the end of the detection object. There is a high possibility that a plurality of arrival positions are detected only in one irradiated direction, and a possibility that a plurality of arrival positions are detected in a plurality of consecutive directions is low. Therefore, as described above, when a plurality of laser light arrival positions are detected in each irradiation direction when the concave mirror 41 (deflection unit) is at a predetermined number of rotation angles in a continuous switching order, detection is performed. A plurality of arrival positions are not detected due to the laser beam being irradiated to the end of the object, but a part of the laser beam hits a minute diffuse object such as fog in each irradiation direction. It can be said that there is a high possibility that a plurality of arrival positions are detected. Therefore, when such a detection result is obtained, if it is determined that the detection result of the front arrival position at a predetermined number of rotation angles is due to noise other than the detection target, it is caused by fog or the like with higher accuracy. It will be easier to remove noise.

In the above configuration, the storage unit 80 (storage unit) that stores the background data that can specify the background object position for each irradiation direction of the laser beam in the scanning range of the laser beam by the scanning unit is provided. In each irradiation direction of the laser beam when the deflecting unit is at a predetermined number of rotation angles in the continuous switching order, the background object position in each irradiation direction determined by the background data as the arrival position of the laser beam by the arrival position detecting means The object to be detected at a short-distance position at a predetermined number of rotation angles, provided that a short-distance position closer than the short-distance position (that is, a single arrival position) is detected and a long-distance position farther than the short-distance position is not detected. Is determined to have been detected.
When a diffusing material such as mist is present in the detection area of the external space, particles of the diffusing material (for example, minute water droplets) are extremely small, so a part of the laser light irradiated in a predetermined direction hits such particles. However, since the remaining portion of the laser beam is irradiated behind the particles, the arrival position of the laser beam in this irradiation direction is at least two positions. Therefore, as in the above configuration, in each irradiation direction, a short-distance position closer to the background object position in each irradiation direction determined by the background data is detected as a laser beam arrival position, and is farther than this short-distance position. When the long distance position is not detected as the arrival position of the laser beam, that is, when there is one laser beam arrival position in each irradiation direction, each laser beam arrival position detected in each irradiation direction (that is, a predetermined number) It is highly possible that each short distance position at the rotation angle is not the position of the minute particles as described above but the position of the detection target. Therefore, if it is determined that the detection target is detected at these short-distance positions on the condition that such a detection result is obtained, the detection target can be detected more accurately.

Further, in the present embodiment, a correction unit is provided, and the correction unit detects the first arrival position by the arrival position detection unit in each irradiation direction of the laser light when the deflecting unit is at any of a plurality of rotation angles. When a second arrival position behind the first arrival position is detected, based on a light reception waveform of reflected light from the first arrival position and a light reception waveform of reflected light from the second arrival position in each irradiation direction By using a correction formula or correction table that can set a correction value in each irradiation direction, the received light waveform of the reflected light from the second arrival position in each irradiation direction is attenuated based on the received light waveform at the first arrival position in each irradiation direction. It is corrected to compensate.
Then, the determination means determines the second arrival position based on the correction result obtained by correcting the received light waveform from the second arrival position in each irradiation direction by the correction means and the background object position in each irradiation direction determined by the background data. It is determined whether or not the object existing in the background is the background, and when it is determined that the object is not the background, it is determined that the detection target is detected at the second arrival positions at a plurality of rotation angles.
When a diffusing material such as mist exists in the detection area of the external space, a part of the laser light irradiated in a predetermined direction hits the particle of the diffusing material, and the remaining laser light irradiates the background object behind When this is done, the amount of laser light applied to the background object will be smaller than normal (when irradiated directly without irradiating a diffusing material such as fog), and the received light waveform of the reflected light from the background object will be This greatly changes from the normal light reception waveform that was originally planned. If the light reception waveform from the background object changes in this way, the calculated position of the background object may deviate from the original position determined by the background data.
On the other hand, when the correction means is provided as described above and two positions (first arrival position and second arrival position) are detected as the laser light arrival positions in each irradiation direction, the second arrival in each irradiation direction is detected. If the received light waveform of the reflected light from the position is corrected so as to compensate for the attenuation based on the received light waveform at the first arrival position in each irradiation direction, normal time at each second arrival position (when laser light is directly irradiated) It becomes easy to guess the waveform contents of the above, and it becomes possible to more accurately determine whether or not the second arrival position is the background object position.

  In the present embodiment, the deflection unit of the scanning unit is configured by the concave mirror 41 configured to be rotatable about the central axis 42a, and the laser light L1 that has passed through the through hole 32 is predetermined in the horizontal direction. It functions so as to be reflected at an angle (in the example of FIG. 1, an angle of 0 ° with respect to the horizontal direction, that is, the same direction) and irradiate the external space. Then, the concave mirror 41 makes light that enters the direction of the predetermined angle with respect to the concave mirror 41 (light that enters in the horizontal direction in the example of FIG. 1) at a condensing point set on the central axis 42a. The light reflected by the reflecting surface 31 of the mirror 30 is received by the light receiving region of the photodiode 20 among the light condensed toward the condensing point. It is like that. In addition, the condensing point when the concave mirror 41 condenses the light entering the horizontal direction may be set on the central axis 42a. For example, it is substantially the same position as the mirror 30 in the vertical direction (for example, in the through hole 32). Position or a position on a virtual plane including the reflective surface 31), or a position above the mirror 30. According to this configuration, since the deflecting unit can be used for both light projection and light reception, the number of parts can be reduced and the size can be reduced compared to a configuration in which a light projection rotary mirror and a light reception rotary mirror are provided separately. Further, since the deflecting portion can be used as the concave mirror 41 to collect reflected light, it is not necessary to arrange a large condensing lens or the like, and it becomes easy to further reduce the size.

  Further, in the configuration of the present embodiment, the projection angle (the angle formed with the horizontal direction in the example of FIG. 1) of the reflected light generated when the projection laser irradiated from the concave mirror 41 at the predetermined angle hits an object in the external space. The reflected light returning to the concave mirror 41 at an angle close to 0 ° is condensed by the concave mirror 41 toward the condensing point, and a part of the reflected light is guided to the photodiode 20 via the mirror 30 and detected. The Rukoto. For example, as shown in FIG. 9, when the projection laser L1 irradiated from the concave mirror 41 is reflected by the object M at a short distance, the projection laser L1 hits the object before being greatly diffused, and is reflected. Is close to a predetermined angle (the emission angle of the laser beam L1 from the position P1) near the irradiation start point of the projection laser (the emission position P1 of the concave mirror 41) on the central axis 42a, as indicated by the one-dot chain line F1 in FIG. It becomes easy to return at an angle. Such reflected light is guided near the central axis 42 a by the concave mirror 41, and a part thereof is reflected by the reflecting surface 31 of the mirror 30 and detected by the photodiode 20. However, the reflected light (refer to the alternate long and short dash line F1) returning to the vicinity of the irradiation start point of the projection laser L1 (the emission position of the concave mirror 41) is guided to the vicinity of the central axis 42a by the concave mirror 41, and some of the light However, since the light passes through the through-hole 32 without being reflected by the mirror 30, the proportion of the light not guided to the photodiode 20 increases, and the amount of light received by the photodiode 20 can be further suppressed. Even if a part of the light reflected by the object at a short distance is incident on the upper and lower ends of the concave mirror 41 at an angle greatly different from the emission angle of the projection laser L1 (see broken lines F2 and F3), Since the light is guided in a direction not related to the guide path to the photodiode 20, it is not received by the photodiode 20.

  Such a feature is very advantageous when it is desired to discriminate fine particles such as fog by detecting a plurality of received light pulses at a certain rotation angle as in the present invention. For example, when the laser light L1 is reflected by the short-distance mist particles when the configuration is such that almost all of the reflected light that enters the deflecting unit from the short-distance object can be guided to the detection means instead of the configuration of the present invention. As shown by the waveform P1 in FIG. 11 (A), the amount of received light immediately reaches the saturation level. Once the amount of received light reaches the saturation level in this way, it takes time until the next reflected light can be detected (that is, until the detected amount of received light decreases to a low level). For this reason, when an object exists immediately behind the fog particles, the light reception pulse of the reflected light from the object may be drowned out by the light reception pulse from the fog particles. For example, when a minute mist particle is present at the position of the object M in FIG. 9 and an object to be detected is present behind it, the received light pulse that detects the mist particle is large as in the waveform P1 in FIG. Since it becomes too much and is integrated with the received light pulse from the object behind it, detection omission of the object will occur. However, in the above-described configuration, as described with reference to FIG. 9, the amount of light received by the photodiode 20 can be effectively suppressed with respect to the reflected light from an object at a short distance. Can be resolved. For example, reflected light from near-distance fog particles can be received with a considerably reduced light receiving level, so that the waveform P1 as shown in FIG. 11A is changed to the waveform P1 ′ shown in FIG. Therefore, even when an object exists immediately behind the fog particles, the received light waveform P2 from the object and the received light waveform P1 ′ from the fog particles can be distinguished from each other. Can be prevented from being missed.

  On the other hand, when the position of the object hit by the projection laser L1 is far from the concave mirror 41, the projection laser L1 is diffused to some extent and then is reflected by the object, and the projection angle (FIG. 1, FIG. 1) in the entire concave mirror 41 is reflected. In the example of 10, the ratio of light (reflected light from an object) entering at an angle close to 0 ° with respect to the horizontal direction increases, and the ratio of light that can be received by the photodiode 20 increases. For example, when the projection laser L1 is reflected by an object M at a considerably far position as shown in FIG. 10, only the vicinity of the irradiation start point of the projection laser L1 (the emission position P1 in the concave mirror 41), such as the alternate long and short dashed lines F41 and F42. In addition, the reflected light having an angle close to the projection angle of the laser beam L1 (that is, the direction close to the horizontal direction) is also distant from the irradiation start point P1 of the projection laser (see the dashed lines F51, F52, F61, and F62). The light entering the entire concave mirror 41 is easily guided to the photodiode 20 by the concave mirror 41 and the mirror 30, and the detection sensitivity can be increased by relatively increasing the amount of received light. In particular, of the reflected light collected toward the photodiode 20 by the concave mirror 41, the ratio of the light passing through the through hole 32 is relatively smaller than that in a short distance, so that loss in the light receiving path can be suppressed. Therefore, the detection sensitivity of reflected light from a long distance can be reliably increased.

[Modification of First Embodiment]
Next, a modification of the first embodiment will be described with reference to FIG. Since this modification is the same as the first embodiment described above except for the shape of the concave mirror, detailed description of parts other than the concave mirror will be omitted, and the drawings, descriptions, symbols, etc. of the first embodiment will be omitted. I will quote it.

  The concave mirror 41 used in the laser radar device according to the modification includes a planar reflecting portion 72 having a flat planar reflecting surface 72a at the incident position of the laser light L1 from the laser diode 10, and a curved concave reflecting surface 71a. And a concave reflecting portion 71, and is rotatable about a central axis 42a passing through the planar reflecting surface 72a. The concave mirror 41 of the first embodiment is configured by a paraboloid (that is, a curved surface configured such that a condensing point is set on the central axis 42a) as the entire reflecting surface 41a is the same as the concave reflecting surface 71a. However, in this modified example, a part (position where the light projecting laser L1 near the position P2 hits) is not a parabolic surface, but a flat surface (planar reflecting surface) inclined at a certain angle with respect to the central axis. 72a). Even in this configuration, the concave mirror 41 is configured to be rotatable about the central axis 42a, and the laser beam L1 that has passed through the through hole 32 is given a predetermined angle (for example, 0 ° with respect to the horizontal direction) by the planar reflecting surface 72a. It is designed to irradiate the external space with reflection. Also in this configuration, at least the concave reflecting portion 71 collects light entering the direction of a predetermined angle (projection laser angle) with respect to the concave mirror 41 toward the condensing point on the central axis 42a. Thus, a part of the light guided toward the condensing point on the central axis 42 a is reflected by the mirror 30 (see FIG. 1 and the like) and received by the photodiode 20. It has become. In addition, in FIG. 12, although the concave mirror 41 used by the modification is shown notionally, the size and shape of a plane reflection part are not restricted to the example of a figure, It can change variously. For example, it is preferable that the outer shape of the orthographic projection when the plane reflecting portion 72 is projected on a horizontal plane (virtual plane orthogonal to the central axis 42a) is a circle centered on the central axis 42a. The diameter of the orthographic projection (the diameter of the circular outer shape) of the portion 72 may be the same as the diameter of the laser beam (spot diameter) at the position P1, and may be slightly larger or slightly smaller than the spot diameter. . Further, the inner surface of the through hole 32 is configured as a cylindrical surface centered on the central axis 42a, and the diameter of the cylindrical surface is slightly larger than the spot diameter of the laser light L1 that passes through the through hole 32. Although desirable, it may be approximately the same as the diameter of the orthographic projection of the planar reflecting portion 72.

  As in this modified example, by providing a plane reflection portion at the irradiation start position of the projection laser L1 (reflection position P1 at the concave mirror 41), the laser light L1 reflected by the concave mirror 41 becomes difficult to diffuse, and the energy of the laser light The density can be increased and the laser beam can be emitted further away. However, in this configuration, since the energy density at a short distance is further increased, the above-described problem in the case where fog is present at a short distance (problem of detection of a rear object due to saturation of the amount of received light) is more remarkable. Become. Therefore, it is more effective to apply the above-described characteristic configuration to such a configuration to suppress the detection sensitivity of reflected light from a short distance and increase the detection sensitivity of reflected light from a long distance.

[Second Embodiment]
Next, a second embodiment will be described with reference to FIGS.
FIG. 13 is a cross-sectional view schematically illustrating the overall configuration of a laser radar device 200 according to the second embodiment. FIG. 13 schematically shows a configuration in which the laser radar device 200 is cut along a predetermined cut surface (a cut surface passing through the center axis 42a and the light receiving position of the photodiode 20) along the rotation center axis 42a of the deflection unit 241. ing. In the following description, the cross section of the transmission plate is shown in white.

  The laser radar device 200 according to the present embodiment has the same configuration as the first embodiment with respect to the case 3, the laser diode 10, the photodiode 20, the mirror 30, the shaft portion 42, the motor 50, and the rotation angle sensor 52. And has the same function as the first embodiment. The control circuit 70 has the same hardware configuration as that of the first embodiment except that the control method is different from that of the first embodiment. In addition, the storage unit 80 has the same hardware configuration as that of the first embodiment except that the stored contents are different from those of the first embodiment. Therefore, the same reference numerals as those in the first embodiment are assigned to these, and detailed description of the hardware configuration and the like is omitted.

  The laser diode 10 corresponds to an example of “laser light generation means” and has the same configuration as that of the first embodiment. Under the control of the control circuit 70, the laser diode 10 receives a pulse current from a drive circuit (not shown), Pulsed laser light (laser light L1) according to the above is intermittently emitted. In the present embodiment, laser light from the laser diode 10 to an object (not shown) outside the apparatus is conceptually indicated by a symbol L1, and a first reflecting portion 73 (to be described later) of the laser light L1 is described. The laser beam irradiated in the horizontal direction from FIG. Further, a laser beam irradiated obliquely downward from a second reflecting portion 74 (FIG. 14 and the like) described later is conceptually indicated by reference numeral L12. On the other hand, when the laser beam L11 irradiated in the horizontal direction hits an object outside the apparatus, a path of reflected light (first reflected light) from this object to the photodiode 20 is conceptually indicated by reference numeral L21. Show. Further, when the laser beam L12 irradiated obliquely downward strikes an object (such as the ground) outside the apparatus, a path of reflected light from this object to the photodiode 220 is conceptually indicated by reference numeral L22. .

  Each of the photodiodes 20 and 220 is configured by, for example, an avalanche photodiode. One photodiode 20 corresponds to an example of “first detection means”, and basically has the same configuration as that of the photodiode 20 used in the first embodiment. When the laser beam L1 is generated and one laser beam (horizontal laser beam L11) branched by the deflecting unit 241 is reflected by an object (not shown) existing in the external space, The generated first reflected light L <b> 21 is configured to be detected via the deflecting unit 241. The reflected light from the horizontal direction is configured to be received by the deflecting unit 241 in a predetermined area in the vertical direction. In FIG. 13, the line L21a is bounded by the vicinity of two lines indicated by reference numerals L21a and L21b. , L21b, the reflected light L2 is reflected by the deflecting unit 241. The other photodiode 220 corresponds to an example of “second detection means”, and the laser beam L1 is generated from the laser diode 10 and the laser beam L1 is branched by the deflecting unit 241 (the lower laser beam). When the laser beam L12 in the direction is reflected by an object in the external space, the second reflected light L22 generated by this reflection is detected via the deflecting unit 241. Incidentally, the reflected light L22 from the obliquely downward direction is also configured to be received by the deflecting unit 241 in a predetermined region. In FIG. 13, the line L22a is bounded by the vicinity of two lines indicated by reference numerals L22a and L22b. , L22b, the reflected light L22 in the region is reflected by the deflecting unit 241.

  Also in this configuration, the lens 60 is provided on the optical axis of the laser light L1 emitted from the laser diode 10, and the mirror 30 is provided in the vicinity of the optical path of the laser light L1 that has passed through the lens 60. The lens 60 is configured as a collimating lens similar to that in the first embodiment, and condenses the laser light L1 generated and diffused by the laser diode 10 and converts it into substantially parallel light. The mirror 30 includes a reflection surface 31 that is inclined at a predetermined angle (for example, 45 °) with respect to the optical axis of the laser beam L1, and a through hole 32 that intersects the reflection surface 31 (specifically, the vertical direction). The laser beam L1 from the laser diode 10 is passed through the through hole 32, while the reflected light L21 from the detection object outside the apparatus (more specifically, the first reflected light L21 entering along the horizontal direction). Is reflected toward the photodiode 20.

  A rotary reflection mechanism 240 is provided on the optical axis of the laser light L1 that passes through the mirror 30. The rotation reflection mechanism 240 includes a deflecting portion 241 configured to be rotatable, a shaft portion 42 connected to the deflecting portion 241, and a bearing (not shown) that rotatably supports the shaft portion 42. The deflection unit 241 is disposed so as to be rotatable about a central axis 42a extending in the vertical direction. The direction of the central axis 42a that is the rotation center of the deflecting unit 241 substantially coincides with the direction of the laser beam L1 that passes through the mirror 30 and enters the deflecting unit 241, and the laser beam L1 enters the deflecting unit 241. The incident position is near the position P1 on the central axis 42a.

  The deflecting unit 241 includes a planar reflecting unit 72 having a planar reflecting surface (planar reflecting surfaces 73a and 74a) disposed on the path of the laser light L1 that has passed through the through hole 32, and wider than the planar reflecting surface. The concave reflecting portion 71 having the concave reflecting surface of the region is configured, and the flat reflecting portion 72 and the concave reflecting portion 71 are configured to rotate integrally around the central axis 42a.

  For example, the planar reflecting portion 72 has an angle (acute angle) formed between the first reflecting portion 73 having the planar reflecting surface 73a in which the angle (angle on the acute angle side) formed with the central axis 42a is set to 45 ° and the central axis 42a. Side angle) is set to be larger than 0 ° and smaller than 45 °, the second reflecting portion 74 having a planar reflecting surface 74a, and the inclination of the first reflecting portion 73 and the second reflecting portion 74 is inclined. Configured differently. The planar reflecting portion 72 configured in this manner reflects the laser light L1 from the laser diode 10 by dividing it into at least two parts in the horizontal direction perpendicular to the central axis 42a and the obliquely lower direction lower than the horizontal direction. ing. That is, of the laser light L1 incident on the planar reflecting portion 72, the light incident on the first reflecting portion 73 is reflected by the first reflecting portion 73 and travels in the horizontal direction. On the other hand, of the laser light L1 incident on the plane reflecting portion 72, the light incident on the second reflecting portion 74 is reflected by the second reflecting portion 74 and is directed obliquely downward. In the present embodiment, assuming a virtual plane including the center axis 42a and including the center of the optical axis of the horizontal laser beam L11, the laser beam L12 directed obliquely downward passes through this virtual plane. ing.

  Thus, in the present embodiment, the portion near the position P1 (the portion of the first reflecting portion 73) on the reflecting surface 241a of the deflecting portion 241 is perpendicular to the direction (the direction of the laser light L1 incident on the reflecting surface 241a). Since the deflection unit 241 rotates about the central axis 42a in the direction coinciding with the direction of the incident laser beam L1, the rotation position (rotation angle) of the deflection unit 241 is approximately 45 °. ) Regardless of whether the incident angle of the laser beam L1 on the above portion (the first reflecting portion 73 portion) is always maintained at about 45 °, and the direction of the laser light L11 from the first reflecting portion 73 is always horizontal (center). Direction perpendicular to the axis 42a). Therefore, when the deflecting unit 241 is rotationally driven by the motor 50, horizontal scanning is performed so that the laser light L11 moves in the horizontal direction along with the rotation. In the present embodiment, the direction of the central axis 42a is the vertical direction (vertical direction, vertical direction), and the plane direction orthogonal to the central axis 42a is the horizontal direction. When the position P1 is used as a reference, the side on which the laser light L1 comes toward the position P1 is the upper side.

  On the other hand, a portion slightly deviating from the central axis 42a at the incident position of the laser beam L1 in the deflecting unit 241 (portion of the second reflecting unit 74) is perpendicular to the planar reflecting surface 74a (the laser beam L1 incident on the reflecting surface 241a). Incline upward so that the angle between the angle and the direction is less than 45 °. Since the deflecting unit 241 rotates around the central axis 42a in the direction coinciding with the direction of the incident laser beam L1, the above-described portion (the second reflecting unit 74) The angle formed between the laser beam L1 and the incident laser beam L1 is always maintained at a constant angle of less than about 45 °, and the direction of the laser beam L12 from the second reflecting portion 74 is set at a fixed angle (0 It is obliquely downward (constant angle larger than 45 ° and smaller than 45 °). Therefore, when the deflection unit 241 is driven to rotate by the motor 50, the laser light L12 is scanned so as to move in the lateral direction while maintaining a certain angle obliquely downward with respect to the horizontal direction. As described above, when the deflection unit 241 is rotationally driven by the motor 50, the upper and lower two laser beams (laser beams L11 and L12 radiated from the deflection unit 241 to the external space move around the central axis 42a. .

  The concave reflecting portion 71 has, for example, an outer surface (concave reflecting surface) configured as a paraboloid, functions as a concave mirror, and is adjacent to the planar reflecting surface (planar reflecting surfaces 73a and 74a) of the planar reflecting portion 72. And the outer surface (concave reflective surface) is arrange | positioned so that the said planar reflective surface may be surrounded. The concave reflecting portion 71 collects the reflected light L21 of a predetermined region (region between L21a and L21b) incident in the horizontal direction while reflecting the reflected light upward, and the focal position of the collected reflected light L21 is The shape is adjusted to be on the central axis 42a. In addition, the reflected light L22 in a predetermined region (region between L22a and L22b) incident obliquely downward is condensed while being reflected upward, and the focal position of the collected reflected light L22 is near the photodiode 220. The shape is adjusted so that

  The shape of the deflection unit 241 will be described in more detail. The outer shape of the plane reflection unit 72 when the deflection unit 241 is viewed in plan (that is, the plane reflection unit 72 when the deflection unit 241 is projected onto a virtual plane orthogonal to the central axis 42a). Of the laser beam L1 in the deflecting unit 241 is substantially coincident with the region of the planar reflecting unit 72 or within the region of the planar reflecting unit 72. It is slightly smaller than the area of the plane reflecting portion 72. In the example of FIGS. 14 and 15, the area of the planar reflecting surface 73 a of the first reflecting portion 73 is larger than the area of the planar reflecting surface 74 a of the second reflecting portion 74, and the center axis 42 a The planar reflecting surface 73a of the first reflecting portion 73 is positioned on the axis.

   The rotary reflection mechanism 240 configured as described above reflects the laser light L1 from the laser diode 10 toward the space by the deflecting unit 241 and returns to the horizontal direction from the object outside the apparatus by the deflecting unit 241. Reflected light (first reflected light L21 that is reflected by the laser beam L11 in the horizontal direction reflected from an object outside the apparatus) is deflected toward the photodiode 20 and reflected from the object outside the apparatus in an oblique direction. The light (second reflected light L22 that is reflected by an obliquely downward laser beam L12 reflected by an object outside the apparatus) is deflected toward the photodiode 220 along a path different from the path of the first reflected light L21. Function.

  The motor 50 and the rotation angle sensor 52 have the same configuration as in the first embodiment, and the motor 50 rotates the shaft portion 42 to rotate the deflection unit 241 connected to the shaft portion 42. The rotation angle sensor 52 detects the rotation angle position of the shaft portion 42 of the motor 50 (that is, the rotation angle position of the deflection unit 241). Also in this configuration, the rotary reflection mechanism 240 and the motor 50 correspond to an example of “scanning means”.

  In the laser radar device 1 configured as described above, when the rotation angle θ of the deflecting unit 241 (the rotation angle from a predetermined reference rotation position (for example, the position where the rotary encoder indicates the origin)) is determined, the horizontal direction from the device is determined. The projection direction of the laser beam L11 is specified. Therefore, if the laser radar device 1 is installed in a specified installation state (for example, an installation state in which the direction of the central axis 42a is vertical), the photodiode 20 receives the reflected light L12 from the object. By detecting the rotation angle of the deflection unit 241 with the rotation angle sensor 52, the orientation of the object can be accurately detected. Whether or not the photodiode 20 receives the reflected light from the object can be determined by whether or not the amount of light received by the photodiode 20 (that is, the output from the photodiode 20) exceeds a threshold, “When the reflected light exceeding the threshold is received by the photodiode 20” is “when the reflected light L21 from the object is received”.

  If a time T1 from when the laser light L1 (pulse laser light) is generated by the laser diode 10 to when the reflected light L12 corresponding to the laser light L11 is detected by the photodiode 20 is detected, this time T1. And the speed of light, the length of the optical path from the generation of the laser light L1 to the reception of the reflected light L21 can be calculated, and the distance from the predetermined reference position (for example, position P1) of the laser radar device 1 to the detected object L can also be accurately obtained. That is, it is possible to accurately detect the distance and the direction from the laser radar device 1 to the detection object.

  In the present embodiment, the rotation angle sensor 52 and the control circuit 70 correspond to an example of “first arrival position detection means”, and the laser light L1 is generated by the laser diode 10, and the first corresponding to the laser light L1. When one reflected light L21 is detected by the photodiode 20, the rotation angle of the deflecting unit 241 when the laser light L1 is generated and the first reflected light L21 is detected by the photodiode 20 from the generation of the laser light L1. Elapsed time T1 to be obtained is obtained, and based on the rotation angle and elapsed time T1, the laser beam arrival position that is the generation source of the first reflected light L21 is detected.

  Further, if the rotation angle θ of the deflecting unit 241 (the rotation angle from a predetermined reference rotation position (for example, the position where the rotary encoder indicates the origin)) is determined, the projection direction of the laser beam L12 obliquely downward from the apparatus is also specified. Is done. Therefore, if the laser radar device 1 is installed in a specified installation state (for example, an installation state in which the central axis 42a is in the vertical direction), the deflection unit when the photodiode 220 receives the reflected light L22 from the object. By detecting the rotation angle 241 with the rotation angle sensor 52, it is possible to accurately detect the azimuth of the object (the azimuth of the position where the second reflected light L22 is generated) to which the laser light L12 in the obliquely downward direction has arrived. Whether or not the photodiode 220 receives the reflected light from the object can be determined by whether or not the amount of light received by the photodiode 220 (that is, the output from the photodiode 220) exceeds a threshold value. “When the reflected light exceeding the threshold value is received by the photodiode 220” is “when the reflected light L22 from the object is received”.

  In this configuration, the rotation angle sensor 52 and the control circuit 70 correspond to an example of “second arrival position detection means”, the laser light L1 is generated by the laser diode 10, and the second reflected light corresponding to the laser light L1. When L22 is detected by the photodiode 220, the rotation angle of the deflecting unit 241 when the laser light L1 is generated and until the second reflected light L22 is detected by the photodiode 220 from the generation of the laser light L1. Elapsed time T2 is obtained, and the arrival position of the laser beam obliquely downward in the external space is detected based on the rotation angle and elapsed time T2.

Next, a detection flow in the laser radar apparatus 200 according to the present embodiment will be described. The general flow of detection is the same as in FIG. 3 used in the first embodiment, and will be described with reference to FIG.
In the present embodiment, detection processing is performed according to the flow shown in FIG. 3A when a predetermined start condition is satisfied (for example, when power is turned on or when a predetermined operation or the like is performed on an operation unit (not shown)). In this detection process, the initial setting process (S1) is first performed, and then the distance measurement process (S2) is repeated.

  The initial setting process of S1 has a flow as shown in FIG. 3B. First, an initial value setting process is performed (S10). In the initial value setting process, various settings such as setting of the rotation reference position of the deflecting unit 241 are performed. Here, the case where the direction of the arrow F1 shown in FIG. 17 is the reference direction of the rotation angle 0 °, the direction of the arrow F2 is the direction of 180 °, and the range of 0 ° to 180 ° is the detection angle range will be described. To do.

  After the process of S10, a process for setting a ranging area (monitoring area) is performed (S11). In this embodiment, in this process, scanning with laser light is performed in a predetermined angle range (0 ° to 180 ° angle range shown in FIG. 17), and obliquely downward at each rotation position (each rotation angle) in this angle range. The arrival position of the laser beam L12 in the direction is detected. Specifically, the deflecting unit 241 is driven to rotate, and the pulse laser beam L1 is sequentially emitted from the laser diode 10 at each rotation position (each rotation angle) to scan the laser beam L12. Note that the rotation speed of the deflection unit 241 and the emission time interval of the pulse laser beam L1 (that is, the emission time interval of the laser beam L12) can be variously set. For example, the deflection unit 241 rotates by 0.5 °. Scanning can be performed at such a timing that the pulse laser beam L1 is emitted every time. Further, it is desirable that the laser beam scan in S11 is performed after confirming that no object is present in the area to be monitored. In this case, each rotational position when each pulse laser beam L1 is emitted. The obliquely downward laser light L12 projected from the deflecting unit 241 at each rotation angle is reflected on the ground or floor (see symbol E in FIG. 16), and a part of the reflected light is incident on the deflecting unit 241 again. And is detected by the photodiode 220. Accordingly, it is possible to calculate the distance from the laser radar device 1 to the ground or the floor surface to which the laser beam L12 reaches when the laser beam L1 is irradiated at each rotational position (for example, the horizontal distance to the arrival position P2). It becomes.

  In the process of S11, as in FIG. 5, the arrival position of the laser beam L12 at each rotation position (each rotation angle) in the detection angle range (here, 0 ° to 180 °) (for example, the laser beam L12 is transmitted at each rotation angle). The distance value in the horizontal direction from the position P1 to the arrival position P2 that reaches the ground or the like can be acquired. The distance value to the arrival position at each rotation position (each rotation angle) detected in this process is a limit position at which the obliquely downward laser beam L12 can be irradiated at each rotation position. In this way, data of the horizontal distance to the arrival position P2 at each rotation position in the detection angle range is obtained. In the embodiment, each of the laser beams L12 at each rotation position (each rotation angle) in the horizontal direction. An area inside the arrival position (that is, an area closer to the laser radar device 1 than each arrival position) is set as a ranging area (monitoring area). In FIG. 17, the locus of the arrival position of the laser beam L12 that is inclined downward is indicated by AR2, and an example of setting the monitoring area is indicated by AR.

  Note that the monitoring area may be set by, for example, data input by an operator without performing the detection operation for the initial setting as described above. In the configuration of the present embodiment, when the laser radar device 1 is installed so that the central axis 42a is in the vertical direction, the ground or floor surface (in FIG. 16, the ground or floor surface is conceptually illustrated by the symbol E). If the height of the position P1 of the laser radar device 1 is known, the inclination of the planar reflecting surface 74a of the second reflecting portion 74 is known, so that the laser beam L12 reaches the arrival position P2. The horizontal distance A2 is determined. That is, when the height of the position P1 from the surface E is h and the angle between the laser beam L12 and the horizontal direction is α, the distance L2 from the position P1 to the arrival position P2 can be obtained by measurement. Therefore, the distance A2 can be obtained as A2 = h / tanα. In this case, when viewed in plan as shown in FIG. 17, the laser beam L12 is on the surface E (ground or floor) on a circle having a radius A2 centered on the position P1 (on the circle indicated by symbol AR2 in FIG. 17). Therefore, the monitoring area may be set so as to be within the circle having the radius A2. For example, in the example of FIG. 17, the monitoring area is set within a substantially semicircle having a radius A1 (where A1 <A2) centered on the position P1.

  As described above, in the present configuration, when the laser radar device 1 is at a predetermined height h from the reference plane E (ground or floor), the central axis 42a is in a direction orthogonal to the reference plane E (ground or floor). The position where the obliquely downward laser beam L12 reaches the reference plane E (ground or floor surface) at each rotation angle of the deflecting unit 241 is configured to be outside the monitoring area at each rotation angle. Yes.

  After the initial setting process shown in FIG. 3B, a distance measurement process is performed (S2). In this distance measurement process, the deflecting unit 241 is rotationally driven and the pulsed laser light L1 is sequentially emitted from the laser diode 10 at each rotational angle, and scanning of the horizontal laser light L11 and the obliquely downward laser light L12 is performed. Then, for example, the light reception waveform at the photodiode 20 (that is, the light reception result waveform of the reflected light L21 of the laser light L11) is acquired for each rotation angle in one cycle of the detection angle range (here, 0 ° to 180 °). The arrival position (distance value) of the horizontal laser beam L11 in the irradiation direction at each rotation angle is calculated (S20). Here, for each rotation angle, a time T1 from the projection of the pulse laser beam L1 to the reception of the reflected light L21 (reception of reflected light exceeding the threshold) is detected, and the horizontal laser is based on this time T1 and the speed of light. The distance value to the laser beam arrival position of the light L11 is calculated. In this process as well, the rotation speed of the deflecting unit 241 and the emission time interval of the pulsed laser light L1 can be set variously. For example, as in the initial setting process, every time the deflecting unit 241 rotates by 0.5 °. Scanning can be performed at such a timing that the pulse laser beam L1 is emitted. Then, after calculating the distance value at each rotation angle in the detection angle range (0 ° to 180 °), noise discrimination processing is performed (S21).

For example, the noise discrimination process of S21 is performed as follows instead of the flow of FIG.
First, it is determined whether or not a plurality of arrival positions are detected by the obliquely downward laser beam L12 at any rotation angle. When the laser beam L12 is irradiated only to a single target (for example, the ground or floor surface) in the laser beam irradiation direction at a certain rotation angle, the light reception waveform at the photodiode 220 at the rotation angle is as shown in FIG. Similarly to 6 (A), only one peak of the received light amount exceeding the threshold appears, and in such a case, it can be determined that a single arrival position is detected at the rotation angle. On the other hand, when a plurality of objects are irradiated with the laser beam L12 in the laser beam irradiation direction at a certain rotation angle, the light reception waveform at the photodiode 220 at the rotation angle is as shown in FIG. A plurality of received light peaks exceeding the threshold value appear, and in such a case, it can be determined that a plurality of arrival positions are detected at the rotation angle. Therefore, it is determined whether or not there is such a rotation angle within the detection angle range (0 ° to 180 °) that the photodiode 220 can detect a plurality of arrival positions during one rotation of the deflecting unit 241. To do. When there is no rotation angle at which a plurality of arrival positions are detected in the detection angle range (0 ° to 180 °), the received light waveform (that is, the photo at each rotation angle) obtained by the horizontal laser beam L11 in the circumference. The position of the detection target is specified based on the received light waveform at the diode 20. The object detection method in this case is the same as the conventional method, and an object is detected in the distance measurement area (that is, the monitoring area set in S11 of FIG. 3B) by scanning with the laser beam L11 irradiated in the horizontal direction. If it can be determined that the object has been detected, the position is specified with the object as a detection target.

  On the other hand, when a plurality of arrival positions are detected by the photodiode 220 as shown in FIG. 6B at any one of a plurality of rotation angles in a certain round, the rounds in which noise is detected in this way, Alternatively, even if the object is detected at the same rotation angle as the noise detected in the horizontal scanning of the laser beam L11 during the subsequent constant rotation including the rotation in which the noise is detected, the result is ignored. That is, even if an object is detected in the monitoring area by irradiation of the laser beam L11 at the rotation angle at which noise is detected by the irradiation of the laser beam L12 (the rotation angle at which the plurality of arrival positions are detected), the object is detected. Instead of treating it as a detection object, treat it as noise. Note that the rotation angle at which noise is not detected by the irradiation of the laser beam L12 (the rotation angle at which the plurality of arrival positions are not detected, that is, the rotation angle that is not an object to be ignored as described above) is the same as in the past. Yes, it is determined whether or not an object is detected in the distance measurement area (that is, the monitoring area set in S11 of FIG. 3B) by scanning with the laser beam L11 irradiated in the horizontal direction. When the detected determination can be made, the position is specified with the object as a detection target. Note that when a plurality of arrival positions are detected by the photodiode 220 as shown in FIG. 6B at any one of a plurality of rotation angles in a certain round, noise such as fog is generated at the rotation angles. You may alert | report by the display on a display part which is not illustrated, audio | voice guidance, data output, etc.

  In this configuration, the control circuit 70 corresponds to an example of “noise detection means”, and detects the second arrival position at each rotation angle at any one of a plurality of continuous rotation angles in the rotation range of one period of the deflection unit 241. When a plurality of laser light arrival positions are detected by the means, it is determined that noise is generated at a plurality of continuous rotation angles.

  In this configuration, the control circuit 70 corresponds to an example of the “determination unit”, and the detection target object is provided that the laser beam arrival position detected by the first arrival position detection unit is within a predetermined monitoring area. Is detected, and when it is determined by the noise detection means that noise is generated at a plurality of rotation angles, the laser beam is detected by the first arrival position detection means at any one of the plurality of rotation angles. Even when the arrival position is detected, it is not determined that the detection target has been detected.

(Main effects of the second embodiment)
When a plurality of arrival positions are detected by the laser beam L12 obliquely downward when there are a plurality of continuous rotation angles within one cycle of the deflecting unit 241, at each of the plurality of rotation angles, fog or the like is detected. It is assumed that a part of the laser beam in the obliquely downward direction L12 is irradiated to the diffuser or the like, and the remaining laser beam is irradiated to the object behind the object (the ground surface, the floor surface, etc.). In this configuration, when such double detection results are obtained at a plurality of continuous rotation angles, it is determined that noise is generated at the plurality of rotation angles. It is easy to take an appropriate response in the apparatus assuming that the resulting noise has occurred. For example, the detection object is detected based on the horizontal laser beam L11 at the same rotation angle as the noise detected in the same rotation as the rotation in which the noise is detected or in a fixed rotation after the noise detection. However, it is easy to take measures such as ignoring the result, or notifying that the noise is generated at the rotation angle at which the noise is detected as error information or the like.

  There is a concern that the same “double detection result” can be obtained even in the case where a part of the laser beam is irradiated to the edge of the detection target and the remaining laser light is irradiated to the object behind the detection target. However, when the above double detection result is obtained at “successive rotation angles”, in such a case (a part of the laser beam is irradiated to the end of the detection target and the remaining laser beam is In the case where the object behind the detection target is not irradiated) is extremely high in terms of probability, and it is difficult to cause a problem that the normal detection target is determined as noise. In particular, the pitch of the rotation angle is made narrower, and the interval when the laser beams of two rotation angles that are continuous in the monitoring area hit the object becomes shorter than the assumed width of the detection object (for example, a person). If comprised in this way, the said effect can be improved further.

  Furthermore, in the above method, it is possible to determine whether or not noise such as fog is generated based on the light reception result within one cycle without rotating the deflecting unit 241 many times. It is possible to speed up detection by effectively reducing the time required to determine whether or not it has occurred. Such noise determination may be performed within the lap in which the noise is detected, or may be performed after the lap in which the noise is detected.

  Further, in this configuration, since the laser beam L1 is divided so that one laser beam L12 (a laser beam mainly used for noise determination) is irradiated obliquely downward, the laser beam L12 has an entire optical path. When it reaches a certain distance without being obstructed, it inevitably reaches an object such as the ground or floor. Therefore, for example, “a noise object such as fog is partially irradiated with laser light, but the remaining laser light does not hit the object far away (for example, far enough that the reflected light cannot be detected), and the rotation angle is Noise detection omission such as “a heavy detection result cannot be obtained” can be prevented, and the detection accuracy of noise such as fog can be significantly improved.

  Further, in this configuration, when the noise detection unit determines that noise is generated at a plurality of rotation angles, the determination unit determines whether the first arrival position detection unit reaches the laser beam at any one of the plurality of rotation angles. Even when the position is detected, it is not determined that the detection object has been detected. When noise is detected based on the laser beam L12 in the obliquely downward direction at any rotation angle, the cause of noise such as fog is detected not only in the obliquely downward direction but also in the horizontal direction at the rotational angle. It can be said that there is a high possibility that it has also affected. Therefore, when it is determined that noise is generated at each rotation angle based on each laser beam L12 irradiated obliquely downward at a plurality of continuous rotation angles, the laser beam is emitted by horizontal irradiation at each rotation angle. If it is not determined that the detection target has been detected even if the arrival position is detected, the risk of misdetecting noise such as fog as a detection target can be reduced as much as possible.

Further, in this configuration, the laser radar device 1 is installed so that the central axis 42a is in a direction orthogonal to the ground or floor surface at a predetermined height h from the reference plane E (ground or floor surface). It has become a thing. The position where the obliquely downward laser beam L12 reaches the reference plane E (the ground surface or the floor surface) at each rotation angle of the deflecting unit 241 is configured to be outside the monitoring area at each rotation angle.
According to this configuration, a horizontal range in which noise can be detected at each rotation angle (that is, a horizontal range from the apparatus to the ground where the laser beam L12 in the oblique direction reaches the ground) is the monitoring area. Since the horizontal range is included, noise such as fog generated in the monitoring area can be detected more reliably while suppressing detection omission. The relationship between the height h from the reference plane E of the laser radar device 1 and the angle of the laser beam L12 obliquely downward (the angle α formed with the horizontal direction), the output of the laser beam L1, and the sensitivity of the photodiode 220 are as follows. A relationship in which the photodiode 220 can reliably detect the reflected light (second reflected light L22) generated by reflecting the laser light L12 on the reference plane E (ground or floor surface) (that is, the photodiode 220 detects the second reflected light L22). When the light is received, the amount of light received by the photodiode 220 may be set so as to exceed a threshold value that is a standard for object detection.

[Other Embodiments]
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  In the first embodiment, the laser radar device in which the scanning direction is limited to the horizontal direction (lateral direction) orthogonal to the central axis 42a is exemplified, but the same applies to a configuration in which the irradiation direction of the laser light can be changed up and down. Applicable to.

  In the first embodiment, the concave mirror 41 is exemplified as the deflecting unit. However, a known structure using a known deflecting unit (for example, a deflecting unit configured as an inclined plane mirror) other than the concave mirror structure may be employed.

  In the second embodiment, the configuration in which the concave reflecting portion 71 is provided around the flat reflecting portion 72 in the deflecting portion 241 is illustrated, but the concave reflecting portion 71 may be configured as a flat mirror.

  In the first embodiment, the inside from the position of the background object is set as the monitoring area. However, the monitoring area may be set separately from the position of the background object. For example, as shown in FIG. 2, a configuration may be adopted in which an area inside a position AR that is a predetermined distance away from the laser radar device 1 in the detection angle range is set as a monitoring area.

DESCRIPTION OF SYMBOLS 1 ... Laser radar apparatus 10 ... Laser diode (laser beam generation means)
20 ... Photodiode (detection means, first detection means)
40: Rotating reflection mechanism (scanning means)
41. Concave mirror (deflection part)
42a ... center axis 50 ... motor (scanning means, drive unit)
52... Rotation angle sensor (arrival position detection means, first arrival position detection means, second arrival position detection means)
70... Control circuit (arrival position detection means, determination means, correction means, first arrival position detection means, second arrival position detection means, noise detection means)
80: Storage unit (storage means)
220... Photodiode (second detection means)
241 ... Deflection part

Claims (9)

Laser light generating means for generating laser light;
A deflection unit configured to deflect the laser beam generated by the laser beam generation unit; and a drive unit configured to rotate the deflection unit, and the deflection unit is rotated by the drive unit to irradiate the external space from the deflection unit. Scanning means for changing the direction of the laser beam,
Detecting means for detecting reflected light from the object when the laser light emitted by the scanning means is reflected by the object existing in the external space;
When the laser light is generated by the laser light generation means, the rotation angle of the deflection unit when the laser light is generated, and the reflected light corresponding to the laser light from the generation of the laser light is the detection means. An arrival position detecting means for detecting an arrival position of the laser beam in the external space based on the rotation angle and the elapsed time,
Determination means for determining that a detection object has been detected on the condition that the arrival position detected by the arrival position detection means is within a predetermined monitoring area;
With
The determination means detects a plurality of arrival positions of the laser light by the arrival position detection means at each irradiation position of the laser light at a plurality of continuous rotation angles in the rotation range of one period of the deflection unit. In this case, the laser radar device is characterized in that the detection result of the arrival position ahead of the rearmost arrival position at a plurality of successive rotation angles is determined to be due to noise other than the detection target.   In the case where a plurality of arrival positions of the laser light are detected by the arrival position detection means in each irradiation direction of the laser light when the deflection unit is at a predetermined number of rotation angles in a continuous switching order. 2. The laser radar according to claim 1, wherein the detection result of the arrival position ahead of the rearmost arrival position at each of the predetermined number of rotation angles is determined to be due to noise other than the detection target. apparatus. Storage means for storing background data capable of specifying a background object position for each laser light irradiation direction in a laser light scanning range by the scanning means;
The determination means is determined by the background data as the arrival position of the laser beam by the arrival position detection means in each irradiation direction of the laser beam when the deflection unit is at a predetermined number of rotation angles in a continuous switching order. The short-distance position closer to the background object position in each irradiation direction is detected and the long-distance position farther than the short-distance position is not detected. The laser radar device according to claim 1 or 2, wherein it is determined that a detection target is detected. Storage means for storing background data capable of specifying a background object position for each irradiation direction of laser light in a scanning range of laser light by the scanning means;
When the arrival position detecting means detects the first arrival position and the second arrival position behind the first arrival position in each irradiation direction of the laser beam when the deflection unit is at any of a plurality of rotation angles. In addition, the second arrival in each irradiation direction by a correction formula or correction table capable of setting a correction value in each irradiation direction based on the light reception waveform of reflected light from the second arrival position in each irradiation direction. Correction means for correcting the light reception waveform of the reflected light from the position so as to compensate for attenuation based on the light reception waveform of the first arrival position in each irradiation direction;
With
The determination means is based on a correction result obtained by correcting the received light waveform from the second arrival position in each irradiation direction by the correction means, and the background object position in each irradiation direction defined by the background data. , It is determined whether or not the object existing at the second arrival position is the background, and when it is determined that the object is not the background, the detection target is detected at the second arrival positions at the plurality of rotation angles. The laser radar device according to claim 1, wherein the laser radar device is determined to be one. Laser light generating means for generating laser light;
The laser beam from the laser beam generating means is configured to be rotatable about a predetermined center axis, and at least vertically divided into a horizontal direction orthogonal to the center axis and a diagonally lower direction lower than the horizontal direction. A deflection unit that reflects each of them and a driving unit that rotates the deflection unit, and the upper and lower two laser beams irradiated to the external space from the deflection unit by rotating the deflection unit by the driving unit are the central axes. Scanning means for moving around,
First detection means for detecting, through the deflection unit, first reflected light generated by the reflection when the horizontal laser beam divided by the deflection unit is reflected by an object existing in the external space; ,
Second detection means for detecting second reflected light generated by the reflection when the laser beam in the obliquely downward direction divided by the deflection unit is reflected by the external space, via the deflection unit;
When the laser light is generated by the laser light generation means and the first reflected light corresponding to the laser light is detected by the first detection means, the deflection unit rotates when the laser light is generated. An angle and an elapsed time from the generation of the laser light to the detection of the first reflected light by the first detection unit are obtained, and the generation source of the first reflected light is determined based on the rotation angle and the elapsed time. First arrival position detection means for detecting a laser beam arrival position,
Determination means for determining that the detection target is detected on condition that the laser beam arrival position detected by the first arrival position detection means is within a predetermined monitoring area;
When the laser light is generated by the laser light generation means and the second reflected light corresponding to the laser light is detected by the second detection means, the deflection unit rotates when the laser light is generated. An angle and an elapsed time from the generation of the laser light until the second reflected light is detected by the second detection means are obtained, and the oblique downward direction in the external space is determined based on the rotation angle and the elapsed time. Second arrival position detecting means for detecting the arrival position of the laser beam;
When a plurality of arrival positions of the laser beam are detected by the second arrival position detection means at each rotation angle at any one of a plurality of rotation angles in the rotation range of one cycle of the deflection unit, these are continued. Noise detection means for determining that noise is generated at a plurality of rotation angles;
A laser radar device comprising:   The determination unit detects the laser beam arrival position by the first arrival position detection unit at any one of the plurality of rotation angles when the noise detection unit determines that noise is generated at a plurality of rotation angles. 6. The laser radar device according to claim 5, wherein even when the detection target is detected, it is not determined that the detection target is detected. The laser radar device is installed so that the central axis is in a direction orthogonal to the ground or floor surface at a predetermined height from the ground or floor surface,
6. The position at which the obliquely downward laser light reaches the ground surface or the floor surface at each rotation angle of the deflecting unit is configured to be outside the monitoring area at each rotation angle. Alternatively, the laser radar device according to claim 6. The reflective surface has a reflective surface that is inclined with respect to the vertical direction when the direction of the central axis serving as the rotation center of the deflection unit is the vertical direction and the direction orthogonal to the vertical direction is the horizontal direction. And passing the laser beam passing in the direction of the central axis to the deflection unit side through the through hole, while reflecting the reflected light from the deflection unit. A mirror that is reflected on the surface and led to the detection means side is provided;
The detection means has a light receiving region for receiving light, and is configured to detect the reflected light incident on the light receiving region,
The deflection unit of the scanning unit includes a concave mirror configured to be rotatable about the central axis, and reflects the laser light that has passed through the through hole at a predetermined angle with respect to the horizontal direction. Configured to irradiate the external space,
The concave mirror is configured to reflect the reflected light entering the direction of the predetermined angle with respect to the concave mirror while collecting the reflected light toward the condensing point on the central axis, and toward the condensing point. 8. The light reflected by the reflecting surface of the mirror among the reflected light collected in this manner is received by the light receiving region of the detecting means. 9. The laser radar device according to item. The concave mirror has a planar reflecting portion having a flat planar reflecting surface disposed at an incident position of the laser light from the laser light generating means, and a concave reflecting portion having a curved concave reflecting surface. And is rotatable about the central axis passing through the plane reflecting surface,
9. The light that enters the direction of the predetermined angle with respect to the concave mirror is reflected while the concave reflecting portion collects light toward a condensing point on the central axis. Laser radar device.

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