JP2020008482A - Object detection device - Google Patents

Abstract

To precisely detect an object even if the number of reflection light from the object is small.SOLUTION: An object detection device 1 includes: a laser radar 10 capable of changing distribution density of laser beam irradiation; an irradiation control part 21 for applying a plurality of laser beams from the laser radar into a detection object area with first distribution density; and an object detection part 22 for detecting an object on the basis of a light reception result of reflection light. The object detection part 22 calculates the number of reflection light reflected by an object for each detected object. The irradiation control part 21 sets a detailed detection area so as to include at least one portion of an object in which the number of reflection light is less than a reference value when objects in which the number of reflection is less than a predetermined reference value exist, and applies laser beams into the detailed detection area with second distribution density higher than first distribution density.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an object detection device that detects an object using a laser radar installed on the ground.

  For example, there is an object detection device that detects an object using a laser radar installed on the ground. 2. Description of the Related Art An object detection device using a laser radar irradiates a plurality of laser beams into a target area where an object is to be detected, and detects an object to be detected based on reflected light of the irradiated laser beam. Such an object detection device is described in Patent Document 1, for example.

JP 2005-513636 A

  In such an object detection device using a laser radar, for example, the longer the distance from the laser radar, the wider the distance between the irradiation positions of the laser light, so the number of laser light irradiating the object decreases, The number of light reflected from the object is also reduced. Further, in such an object detection device, for example, when an object having many black portions is irradiated with laser light, the number of light reflected from the object decreases depending on the color of the object. For this reason, in this technical field, there is a demand for an object detection device that can accurately detect an object even when the number of reflected lights from the object is small.

  An object detection device according to one aspect of the present invention is configured to irradiate a plurality of positions in a detection target region with laser light, receive reflected light of the irradiated laser light, and distribute laser light irradiation in the detection target region. A laser radar installed on the ground whose density can be changed, and an irradiation controller for irradiating a plurality of laser beams from the laser radar to the detection target area at a first distribution density in each scan cycle for detecting an object in the detection target area And an object detection unit that detects an object based on a result of receiving the reflected light for each scan cycle received by the laser radar, and the object detection unit includes, for each detected object, the reflected light reflected by the object. When the number of reflected lights calculated by the object detection unit is smaller than a predetermined reference value, at least one of the objects whose reflected light number is smaller than the reference value is calculated. The detailed detection area is set in the detection target area so as to include the laser light, and in the next scan cycle, the detailed detection area is irradiated with laser light at a second distribution density higher than the first distribution density to perform detection. A region other than the detailed detection region in the target region is irradiated with laser light at the first distribution density.

  When an object having a small number of reflected light is present, the object detection device irradiates a laser beam with a second distribution density having a high density in a next scan cycle in a detailed detection area including at least a part of the object. I do. Thus, an object having a small number of reflected light is irradiated with a large amount of laser light in the next scan cycle. Therefore, the object detection device can increase the number of reflected lights reflected by the object. As described above, the object detection device can accurately detect the object even when the number of reflected lights from the object is small.

  In the object detection device, the irradiation control unit includes at least a part of the object in which the number of reflected lights calculated by the object detection unit is less than the reference value, and which is far from the laser radar by a predetermined reference distance or more. The detailed detection area may be set as described above. In this case, the object detection device can irradiate a large amount of laser light in the next scan cycle even for an object irradiated with a small number of laser lights due to a long distance from the laser radar. Thus, the object detection device can accurately detect a distant object.

  In the object detection device, a laser radar irradiates a laser beam with a predetermined irradiation cycle, and reflects the laser beam radiated from the irradiating portion toward a detection target area, and also sets a reflection angle of the laser beam. A reflector that reflects the laser light at a plurality of positions in the detection target area by changing the position, and a light receiving unit that receives the reflected light of the laser light reflected by the object, the irradiation control unit includes: By changing the irradiation period of the laser light, the distribution density of the irradiation of the laser light may be changed. In this case, the object detection device can easily change the distribution density of the laser light irradiation by changing the irradiation cycle of the laser light in the irradiation unit.

  According to one aspect of the present invention, even when the number of reflected lights from an object is small, the object can be detected with high accuracy.

It is a figure showing the schematic structure of the object detecting device concerning an embodiment. FIG. 3 is a diagram illustrating a detailed detection area set in a detection target area for detecting an object. 5 is a flowchart illustrating a flow of an object detection process performed by the object detection device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

  The object detection device 1 illustrated in FIG. 1 detects a person, a vehicle, and the like moving on a road as objects to be detected. The detection result of the object detection device 1 is transmitted to a higher-level device or the like of the object detection device 1 and used for various processes in the higher-level device or the like. The object detection device 1 includes a laser radar 10 and a calculation unit 20.

  The laser radar 10 irradiates a plurality of positions in a detection target area, which is a target area for object detection, with laser light, and receives reflected light of the irradiated laser light. The laser radar 10 is also called a lidar (Light Detection and Ranging) or a Laser Range Finder. The laser radar 10 is fixed to a support member such as a pillar installed on the ground or a wall of a building. The laser radar 10 may be installed on the ground. In the present embodiment, the object detection device 1 detects a person, a vehicle, or the like moving on a road as an object to be detected. For this reason, the laser radar 10 is installed so that a vehicle or the like moving on a road can be looked down from above. The laser radar 10 irradiates a plurality of laser beams from an upper position toward a road surface of a road, and receives light reflected by an object.

  The laser radar 10 includes an irradiation unit 11, a reflection unit 12, and a light reception unit 13. The irradiation unit 11 includes a light emitting element that generates a laser beam. The irradiating unit 11 irradiates a laser beam at a predetermined irradiation cycle. The reflection unit 12 includes a mirror that reflects the laser light. The reflection unit 12 reflects the laser light emitted from the irradiation unit 11 toward the detection target area by a mirror. In addition, the reflection unit 12 can change the angle of the mirror. The reflection unit 12 reflects the laser light to a plurality of positions in the detection target area by changing the angle of the mirror to change the reflection angle of the laser light. Thereby, a plurality of positions in the detection target region are irradiated with the laser light. Further, the reflection unit 12 reflects the reflected light reflected by the object and returned to the laser radar 10 toward the light receiving unit 13. The light receiving unit 13 receives the light reflected by the object via the reflecting unit 12.

  Further, the laser radar 10 can change the distribution density of the laser light irradiation in the detection target area. That is, the laser radar 10 can irradiate a part of the detection target region with laser light at a distribution density different from that of the other regions. In the present embodiment, the laser radar 10 irradiates the laser beam by changing the irradiation cycle when the irradiation unit 11 irradiates the laser beam while keeping the changing speed of the mirror angle by the reflection unit 12 constant. Change the distribution density of. For example, the irradiation part 11 increases the distribution density of the laser light irradiation by increasing the irradiation period of the laser light.

  The laser radar 10 irradiates a plurality of positions in the detection target area with laser light in each scan cycle for detecting an object in the detection target area based on an instruction from the arithmetic unit 20. In addition, the laser radar 10 changes the distribution density of laser light irradiation based on an instruction from the arithmetic unit 20. The laser radar 10 outputs the result of receiving the laser beam to the calculation unit 20.

  The calculation unit 20 detects an object to be detected based on the result of receiving the laser light in the laser radar 10. The arithmetic unit 20 is, for example, an electronic control unit having a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], and the like. In the arithmetic unit 20, for example, various programs are implemented by loading a program stored in the ROM into the RAM and executing the program loaded into the RAM by the CPU. The calculation unit 20 may be configured by a plurality of electronic control units.

  The calculation unit 20 functionally includes an irradiation control unit 21 and an object detection unit 22. The object detection unit 22 acquires, from the laser radar 10, the result of receiving the reflected light when the plurality of positions in the detection target area are irradiated with the laser light. The light reception result is information in which the irradiation position (direction of irradiation) of the laser light and the reflection position (distance to the reflection position) of the laser light are associated with each reflection light.

  The object detection unit 22 detects an object based on the result of receiving the reflected light for each scan cycle received by the laser radar 10. Specifically, the object detection unit 22 detects the position of the object (the direction from the laser radar 10) and the distance to the object (the distance from the laser radar 10) based on the result of receiving the reflected light. The object detection unit 22 can detect the position of the object and the distance to the object by a known method based on the result of receiving the reflected light. For example, the object detection unit 22 may determine that the reflection positions of the reflected light are close to each other as one object and detect the position and the distance of the object. In addition, the object detection unit 22 determines the type of the detection target object, such as whether the detected object is a person or a vehicle. Note that the object detection unit 22 can determine the type of the detection target object based on the result of receiving the reflected light by a known method. For example, the object detection unit 22 may determine the type based on characteristics of the shape of the detected object.

  The object detection unit 22 may track the object based on the position of the detection target object detected in each scan cycle. Further, the object detection unit 22 calculates the number of light reflected by the object for each detected object.

  Here, the object detection unit 22 detects the object based on the reflected light reflected at a position at a height of the road from the road surface equal to or higher than a predetermined height. Thus, the object detection unit 22 can prevent the road surface from being detected as an object. Further, the object detection unit 22 can suppress detection of an object other than the detection target (for example, a small animal, dust blown by the wind, or the like) existing on the road surface.

  In the present embodiment, the object detection unit 22 detects an object including two or more reflected lights. Objects that include only one point of reflected light are excluded from detection targets. Thereby, the object detection unit 22 can suppress erroneous detection that an object is present due to, for example, noise or the like. However, the object detection unit 22 is not limited to detecting an object including two or more reflected lights, and may detect an object including a predetermined number or more of reflected lights.

  The irradiation control section 21 controls the irradiation of the laser beam in the laser radar 10. The irradiation control unit 21 causes the laser radar 10 to irradiate the detection target area with a plurality of laser beams at the first distribution density in each scan cycle for detecting an object in the detection target area. The first distribution density is predetermined.

  When there is an object whose number of reflected lights calculated by the object detection unit 22 is less than a predetermined reference value, the irradiation control unit 21 includes at least a part of the object whose number of reflected lights is less than the reference value. First, a detailed detection area is set in the detection target area. In the present embodiment, the predetermined reference value for the number of reflected lights is three. However, the predetermined reference value of the number of reflected lights is not limited to three. As the predetermined reference value of the number of reflected lights, for example, any value of 2 or more and 10 or less may be set.

  Here, the details of the detailed detection area set in the detection target area will be described with reference to FIG. As shown in FIG. 2, reflected light P1 and P2 are received at a right portion in the detection target region L. In this case, the object detection unit 22 detects that the object X1 exists in a portion including the positions where the reflected lights P1 and P2 are received. Then, the object detection unit 22 calculates the number of reflected lights reflected by the object X1. Here, the number of reflected lights reflected by the object X1 is two.

  Since the number of reflected lights reflected by the object X1 is less than a predetermined reference value (less than 3), the irradiation control unit 21 sets the detailed detection area in the detection target area L to include at least a part of the object X1. La is set. Note that the detailed detection area La only needs to include at least a part of the object X1 detected based on the reflected lights P1 and P2, and may include the entire object X1. Further, the size of the detailed detection area La can be set as appropriate. For example, the irradiation control unit 21 can set a predetermined area centered on the center coordinates of the object X1 as the detail detection area La.

  Note that, as shown in FIG. 2, a plurality of reflected lights P3 are detected in a left portion in the detection target region L. The plurality of reflected lights P3 are adjacent to each other. In this case, the object detection unit 22 detects that the object X2 exists at the position where the plurality of reflected lights P3 are detected. The number of light beams reflected by the object X2 is nine. Therefore, in the present embodiment, the object detection unit 22 does not set the detailed detection area La for the object X2.

  Here, when setting the detailed detection area, the irradiation control unit 21 is an object in which the number of reflected lights calculated by the object detection unit 22 is less than the reference value and is equal to or more than a predetermined reference distance from the laser radar 10. The detailed detection area may be set to include at least a part of a distant object. That is, when setting the detailed detection area, the irradiation control unit 21 may set the detailed detection area only for a distant object.

  When the detailed detection area La is set, the irradiation control unit 21 supplies the laser beam from the laser radar 10 to the detailed detection area La at the second distribution density higher than the first distribution density in the next scan cycle. Irradiate. Further, the irradiation control unit 21 causes the laser radar 10 to irradiate a region other than the detailed detection region La in the detection target region L with the first distribution density.

  As described above, the laser radar 10 can change the distribution density of laser beam irradiation by changing the irradiation cycle of the irradiation unit 11. The irradiation control unit 21 changes the distribution density of the laser light irradiation by changing the irradiation cycle of the laser light in the irradiation unit 11. Specifically, the irradiation control unit 21 controls the irradiation cycle of the irradiation unit 11 so that the laser beam is irradiated at the second distribution density in the detailed detection area La. Similarly, the irradiation control unit 21 controls the irradiation cycle of the irradiation unit 11 so that a region other than the detailed detection region La in the detection target region L is irradiated with the laser beam at the second distribution density.

  By irradiating the detailed detection area La with laser light at the second distribution density, the object X1 existing in the detection target area L is irradiated with a large amount of laser light, and the number of reflected lights reflected by the object X1 Increase. Accordingly, the object detection unit 22 performs detection based on the reflected light of the laser light irradiated at the second distribution density, thereby performing detection based on the reflected light of the laser light irradiated at the first distribution density. The object X1 can be detected with higher accuracy than in the case.

  Specifically, for example, when the object X1 is located at a position distant from the laser radar 10, the distance between the irradiation positions of the laser light increases as the object X1 moves away from the laser radar 10. Therefore, even if the object X1 is detected in the current scan cycle, the object X1 may not be detected in the next scan cycle depending on the moving position of the object X1. Even in such a case, the possibility that the object X1 is irradiated with the laser light is increased by irradiating the detailed detection area La including the object X1 with a large amount of laser light in the next scan cycle. Thereby, the object detection unit 22 can accurately detect the object X1 based on the reflected light of the laser light irradiated at the second distribution density.

  Further, for example, when there are many black portions where the color of the outer surface of the object X1 is difficult to reflect the laser beam, in the current scan cycle, the laser beam is irradiated on the non-black portion of the object X1 and the object X1 is detected. Also, depending on the moving position of the object X1, the object X1 may not be detected in the next scan cycle. Even in such a case, by irradiating a large amount of laser light in the detailed detection area La including the object X1 in the next scan cycle, it is possible to irradiate the non-black portion of the object X1 with laser light. The nature increases. Thereby, the object detection unit 22 can accurately detect the object X1 based on the reflected light of the laser light irradiated at the second distribution density.

  Next, the flow of an object detection process performed by the object detection device 1 will be described with reference to FIG. Note that the processing illustrated in FIG. 3 is started from the start when an instruction to start the object detection processing is issued from a higher-level device of the object detection apparatus 1 or the like. The process illustrated in FIG. 3 ends when an instruction to end the object detection process is issued from a higher-level device of the object detection device 1 or the like.

  As shown in FIG. 3, the irradiation control unit 21 controls the laser radar 10 to irradiate the detection target area with the laser light at the first distribution density (S101). The irradiation control unit 21 determines whether the irradiation of the laser beam has been completed at the first distribution density at all positions in the detection target region (S102). If the irradiation has not been completed at all positions (S102: NO), the irradiation control unit 21 repeats the processing of S101 and S102 until the irradiation has been completed at all positions.

  When the irradiation has been completed for all the positions (S102: YES), that is, when the irradiation for the current one scan cycle has been completed, the object detection unit 22 determines based on the result of receiving the reflected light for the current one scan cycle. Then, a process of detecting an object is executed (S103). The object detection unit 22 determines whether an object has been detected (S104). If no object has been detected (S104: NO), the calculation unit 20 returns to the process of S101 again and starts irradiation of laser light in the next scan cycle. On the other hand, when an object is detected (S104: YES), the object detection unit 22 calculates the number of light reflected by the detected object (S105). Then, the irradiation control unit 21 determines whether or not there is an object whose number of reflected lights calculated by the object detection unit 22 is less than the reference value (S106). When there is no object whose number of reflected lights is less than the reference value (S106: NO), the calculation unit 20 returns to the process of S101 again and starts irradiation of laser light in the next scan cycle.

  When there is an object whose number of reflected lights is less than the reference value (S106: YES), the irradiation control unit 21 details in the detection target region so as to include at least a part of the object whose number of reflected lights is less than the reference value. A detection area is set (S107). After setting the detailed detection area, the irradiation control unit 21 starts irradiation of laser light in the next scan cycle. Specifically, the irradiation control unit 21 irradiates the laser beam from the laser radar 10 with the second distribution density in the detailed detection area, and the first distribution density in the area other than the detailed detection area in the detection target area. Irradiates laser light from the laser radar 10 (S108).

  The irradiation control unit 21 determines whether or not the irradiation of the laser beam has been completed at the first distribution density and the second distribution density at all positions in the detection target area in the current scan cycle (S109). If the irradiation has not been completed at all positions (S109: NO), the irradiation control unit 21 repeats the processing of S108 and S109 until the irradiation has been completed at all positions. When the irradiation has been completed for all the positions (S109: YES), that is, when the irradiation for the current one scan cycle has been completed, the object detection unit 22 performs the process of detecting an object in S103 described above.

  As described above, when there is an object whose number of reflected lights is less than the reference value, in the processing of S107 to S109, a detailed detection area is set and laser light irradiation is performed at the first distribution density and the second distribution density. . At the start of the object detection process, and when there is no object whose number of reflected lights is less than the reference value, in the processes of S101 and S102, laser light irradiation is performed at the first distribution density.

  As described above, when there is an object having a small number of reflected lights, the object detection device 1 sets the second distribution density having a high density in the next scan cycle in the detailed detection area including at least a part of the object. Is irradiated with laser light. Thus, an object having a small number of reflected light is irradiated with a large amount of laser light in the next scan cycle. Therefore, the object detection device 1 can increase the number of light reflected by the object. As described above, the object detection device 1 can accurately detect the object even when the number of reflected lights from the object is small.

  When setting the detailed detection area, the irradiation control unit 21 may set the detailed detection area only for a distant object. In this case, the object detection device 1 can irradiate a large amount of laser light in the next scan cycle even for an object that is irradiated with a small number of laser lights because the distance from the laser radar 10 is long. Thus, the object detection device 1 can accurately detect a distant object.

  The irradiation control unit 21 can change the distribution density of the laser light irradiation by changing the irradiation cycle of the laser light in the irradiation unit 11. Here, when the irradiation cycle of the laser beam is made faster, the amount of heat generated by the irradiation unit 11 increases. The object detecting apparatus 1 does not irradiate the entire target area with laser light at the second distribution density, but only for an object that may be difficult to detect with high accuracy due to a small number of reflected lights. (Only for the detailed detection area), the laser beam is irradiated at the second distribution density. Thereby, the object detection device 1 can accurately detect an object while suppressing heat generation of the irradiation unit 11.

  As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above embodiments. For example, the laser radar 10 is not limited to changing the distribution density of the laser light irradiation by changing the irradiation cycle of the laser light in the irradiation unit 11. For example, the laser radar 10 changes the distribution density of laser light irradiation by adjusting the direction of reflection of the laser light in the reflecting unit 12 while keeping the irradiation cycle of the laser light in the irradiation unit 11 constant. Is also good.

  The object detection device 1 is not limited to detecting a person or the like moving on a road. For example, the object detection device 1 may detect entry of a person or a vehicle into a facility such as a railroad crossing or a facility such as a warehouse.

REFERENCE SIGNS LIST 1 object detection device 10 laser radar 11 irradiation unit 12 reflection unit 13 light reception unit 20 calculation unit 21 irradiation control unit 22 object detection unit L detection target area La detailed detection areas P1, P2, P3 reflected light X1, X2 object

Claims (3)

A plurality of positions in the detection target area are irradiated with laser light to receive the reflected light of the laser light and are installed on the ground capable of changing the distribution density of the laser light irradiation in the detection target area. Laser radar and
For each scan cycle for detecting an object in the detection target area, an irradiation control unit configured to irradiate the laser light in the detection target area with a plurality of the laser beams at a first distribution density.
An object detection unit that detects the object based on a result of receiving the reflected light for each scan cycle received by the laser radar,
With
The object detection unit, for each of the detected objects, calculates the number of the reflected light reflected by the object,
The irradiation control unit, when the number of the reflected light calculated by the object detection unit there is less than a predetermined reference value of the object, at least the number of the reflected light of the object less than the reference value A detail detection area is set in the detection target area so as to include a part thereof, and in the next scan cycle, the laser is provided in the detail detection area at a second distribution density higher than the first distribution density. An object detection device that irradiates light and irradiates the laser light at the first distribution density to an area other than the detailed detection area in the detection target area.   The irradiation control unit, the number of the reflected light calculated by the object detection unit is less than the reference value, and at least a part of the object present at a distance more than a predetermined reference distance from the laser radar. The object detection device according to claim 1, wherein the detailed detection region is set to include the detailed detection region. The laser radar,
An irradiation unit that irradiates the laser light at a predetermined irradiation cycle,
The laser light emitted from the irradiation unit is reflected toward the detection target area, and the laser light is reflected at a plurality of positions in the detection target area by changing a reflection angle of the laser light. A reflector,
A light receiving unit that receives the reflected light of the laser light reflected by the object,
With
The object detection device according to claim 1, wherein the irradiation control unit changes a distribution density of the laser light irradiation by changing an irradiation cycle of the laser light in the irradiation unit.

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