Detection device and detection method

Abstract

To realize a system capable of determining the presence or absence of an object to be detected in a whole area of an area to be detected on the basis of point group data acquired by receiving a reflection wave of laser irradiation from a predetermined position.SOLUTION: A detection device 10 detects an object to be detected present in an area to be detected on the basis of point group data 171 acquired by receiving a reflection wave of laser irradiation from a predetermined position. The detection device 10 includes: a division unit 151 that divides the area to be detected into a plurality of unit detection areas on the basis of a predetermined division condition that a size of the unit detection area gradually increases as a distance from the predetermined position increases supposing a predetermined infinite planar state; and a presence / absence determination unit 155 that determines the presence or absence of the object to be detected in a unit of the unit detection area by detecting a reduction unit detection area where the quantity of the point group for each unit detection area based on the point group data 171 satisfies a predetermined reduction condition.SELECTED DRAWING: Figure 16

Description

Technical Field

[0001] The present invention relates to a detection device that detects a detection target object within a detection target area and the like.

Background Art

[0002] Conventionally, a technology has been known in which a roadside unit is installed near a road in an area (detection target area) where autonomous driving is performed to detect objects on the road and around the road (see, for example, Patent Document 1). The roadside unit is equipped with sensors such as LiDAR (Light Detection And Ranging) and detects objects such as vehicles and pedestrians.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when detecting an object using a sensor such as LiDAR, point cloud data is acquired by receiving the reflected wave of laser irradiation from the installation position of the sensor. Therefore, in principle, the point cloud density decreases as the distance from the installation position of the sensor increases. When the detection target area becomes wider, a single sensor cannot detect an object to be detected within the detection target area, particularly an object moving to a position far from the installation position of the sensor, with high resolution. Therefore, it has often been necessary to install multiple sensors at various locations while overlapping the areas covered by each sensor according to the width of the detection target area. However, when installing and operating multiple sensors, the installation cost and maintenance cost of the sensors increase. Therefore, there has been a demand to configure a detection system for a detection target object with as few sensors as possible. For this purpose, focusing on a single sensor, a mechanism is required that can determine the presence or absence of a detection target object throughout the entire detection target area as wide as possible that the single sensor can cover based on the point cloud data acquired by receiving the reflected wave of laser irradiation from the predetermined position where the single sensor is installed.

[0005] The problem to be solved by the present invention is to realize a mechanism capable of determining the presence or absence of a detection target object throughout the entire detection target area based on the point cloud data acquired by receiving the reflected wave of laser irradiation from a predetermined position.

Means for Solving the Problem

[0006] A first invention for solving the above problems is a detection device that detects a detection target object existing in a detection target area based on point cloud data obtained by receiving a reflected wave of laser irradiation from a predetermined position, the detection target area being divided into a plurality of the unit detection areas based on a predetermined division condition in which the size of the unit detection area gradually increases as the distance from the predetermined position increases when assuming a predetermined infinite planar state (for example, the dividing unit 151 in FIG. 16), and a presence / absence determination unit (for example, the presence / absence determination unit 155 in FIG. 16) that determines the presence or absence of the detection target object in units of the unit detection areas by detecting a reduced unit detection area in which the number of point clouds for each unit detection area based on the point cloud data satisfies a predetermined reduction condition.

[0007] According to the first invention, the detection target area is divided into a plurality of unit detection areas such that the size of the unit detection area gradually increases as the distance from the predetermined position increases when assuming a predetermined infinite planar state, and by detecting a reduced unit detection area in which the number of point clouds satisfies a predetermined reduction condition, it is possible to determine the presence or absence of the detection target object in units of the unit detection areas.

[0008] A second invention is the detection device according to the above invention, wherein the presence / absence determination unit determines a unit detection area closer to the predetermined position than the reduced unit detection area as a candidate unit detection area where the detection target object exists.

[0009] A third invention is the detection device according to the above invention, wherein when a plurality of the reduced unit detection areas are connected, the presence / absence determination unit determines a unit detection area closer to the predetermined position than the reduced unit detection area closest to the predetermined position among the connected reduced unit detection areas as the candidate unit detection area.

[0010] A fourth invention is the detection device according to the above invention, wherein the presence / absence determination unit determines whether the detection target object exists in the candidate unit detection area by using the number of point clouds in the candidate unit detection area based on the point cloud data.

[0011] According to the second invention, a unit detection area closer to a predetermined position than the reduction unit detection area can be determined as a candidate unit detection area. Further, according to the third invention, when a plurality of reduction unit detection areas are connected, a unit detection area closer to a predetermined position than the reduction unit detection area closest to the predetermined position can be determined as a candidate unit detection area. And according to the fourth invention, it is possible to determine whether or not a detection target object exists in the candidate unit detection area.

[0012] The fifth invention is a detection device in the above invention, wherein the reduction condition is that the number of point clouds has continuously satisfied a predetermined reduction quantity condition for a predetermined time or more.

[0013] According to the fifth invention, a unit detection area in which the number of point clouds has continuously satisfied a reduction quantity condition for a predetermined time or more can be detected as a reduction unit detection area.

[0014] The sixth invention is a detection device in the above invention, wherein the dividing means performs division based on a division condition in a predetermined reset state of the number of point clouds for each unit detection area based on the point cloud data.

[0015] According to the sixth invention, division based on a division condition can be performed in a predetermined reset state based on the number of point clouds in a unit detection area.

[0016] The seventh invention is a detection device in the above invention, wherein the dividing means determines that the reset state has arrived and performs division of the detection target area when at least including a reset condition that a state where the number of point clouds does not satisfy a predetermined allowable condition continues for a predetermined reset determination time for the unit detection area that exists.

[0017] According to the seventh invention, when the number of point clouds in a unit detection area satisfies a reset condition, it can be determined that the reset state has arrived, and division based on a division condition can be performed.

[0018] The eighth invention is a detection device further comprising detection object estimation means (for example, the detection object estimation unit 157 in FIG. 16) for estimating the position and / or size of the detection object using the point group of the reduction unit detection area and the point group of the unit detection area determined by the presence / absence determination means to be where the detection object exists, in the above invention.

[0019] According to the eighth invention, the position and size of the detection object can be estimated from the point group of the reduction unit detection area and the point group of the unit detection area determined to be where the detection object exists.

[0020] The ninth invention is a detection method for detecting a detection object existing in a detection target area based on point group data obtained by receiving a reflected wave of laser irradiation from a predetermined position, the method including dividing the detection target area into a plurality of the unit detection areas based on a predetermined division condition in which the size of the unit detection area gradually increases as the distance from the predetermined position becomes farther when a predetermined infinite plane state is assumed, and determining the presence or absence of the detection object in units of the unit detection area by detecting a reduction unit detection area in which the number of point groups for each unit detection area based on the point group data satisfies a predetermined reduction condition.

[0021] According to the ninth invention, a detection method having the same effect as the first invention can be realized.

Brief Description of the Drawings

[0022]

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Best Mode for Carrying Out the Invention

[0023] Hereinafter, with reference to the drawings, preferred embodiments of the present invention will be described. Note that the present invention is not limited by the embodiments described below, and the applicable forms of the present invention are not limited to the following embodiments. Also, in the description of the drawings, the same reference numerals are given to the same parts. In the present embodiment, as the detection target object, a moving object such as a vehicle or a pedestrian will be described as an example.

[0024] FIG. 1 is a schematic diagram showing an application example of the detection device 10 in the present embodiment, and shows an area 5 on the road 3 as a detection target area from the side. FIG. 2 is a schematic diagram showing the detection target area 5 from above. The detection device 10 of the present embodiment detects a detection target object 7 such as a vehicle or a pedestrian existing in the detection target area 5 based on the positioning result by the sensor unit 1 installed at a high place on the roadside or the like.

[0025] The sensor unit 1 is composed of a laser sensor such as LiDAR (Light Detection And Ranging), and is a device that acquires point cloud data by receiving the reflected wave of laser irradiation from a predetermined installed position P. The sensor unit 1 obtains the distance from the reflection time until the reflected wave is received, locates the position of the object, etc. with reference to the irradiation direction, etc., and acquires the positioning result as point cloud data in three-dimensional coordinates. In this embodiment, the point cloud data is acquired at a predetermined acquisition period and output to the detection device 10.

[0026] More specifically, as shown in FIG. 2, the sensor unit 1 scans the laser beam circularly within a fan-shaped range in a plan view centered on the predetermined position P, and acquires the position of one point for each irradiation and reception of the reflected wave, thereby acquiring the three-dimensional coordinates of each point irradiated toward the detection target area 5. In principle, the density of the point cloud constituting the point cloud data decreases as the distance from the predetermined position P increases. Here, in FIG. 2, the range including the detection target area 5 is partitioned so that the quantity of the point cloud for each grid (hereinafter also referred to as "point cloud quantity") is about the same. Since the density of the point cloud decreases as the distance from the predetermined position P increases, the grid partition is narrow on the near side as seen from the predetermined position P and wider on the far side. That is, on the far side of the detection target area 5, the distance between adjacent points is farther than on the near side, so the detection accuracy (resolution) of the detection target object decreases accordingly. Therefore, even on the far side of the detection target area 5 far from the predetermined position P, a mechanism for detecting the detection target object without omission is required.

[0027] [Details] Figs. 3 to 5 are top views of examples of the point cloud data acquired by the sensor unit 1. The predetermined position where the sensor unit 1 is installed is a position slightly to the left of the center of the lower end side as viewed in Figs. 3 to 5, and is at a predetermined height from the ground. The point cloud data in Figs. 3 to 5 is the point cloud data acquired in a scene where a vehicle, which is an object to be detected, travels so as to approach the sensor unit 1 from the back side to the front side of the detection target area. One point obtained for one irradiation and reception of the laser light corresponds to one white point. In Figs. 3 to 5, the object to be detected and the location of its "shadow" are shown surrounded by a double line formed by overlapping a white line and a black broken line. The "shadow" here refers to the range where the laser light cannot reach because the laser light is blocked by the object to be detected as viewed from the sensor unit 1. As shown in Figs. 3 to 5, when the state of the detection target area changes from a state where there is no object to be detected to a state where there is an object to be detected, the laser light that was being irradiated on the ground when there was no object to be detected is irradiated and reflected by the object to be detected. Therefore, the amount of the point cloud at the outer surface portion closer to the sensor unit 1 of the object to be detected increases compared to when there is no object to be detected. Further, the presence of the object to be detected creates a "shadow" on the rear side of the object to be detected as viewed from the sensor unit 1. The "shadow" did not exist when there was no object to be detected. At the location of the "shadow", the laser light is blocked by the object to be detected and cannot reach, so the amount of the point cloud decreases compared to when there is no object to be detected. As shown in Figs. 3 to 5, the "shadow" can be determined to exist or not even at a distance from the sensor unit 1. The detection device 10 determines the presence or absence of the object to be detected in the detection target area by utilizing such an increase or decrease in the amount of the point cloud.

[0028] FIG. 6 and FIG. 7 are diagrams for explaining the principle of determining the presence or absence of a detection target object in the present embodiment. FIG. 6 is a graph showing the point cloud amount on line L in FIG. 2 along line L from the side of a predetermined position P, with the vertical axis representing the point cloud amount and the horizontal axis representing the distance from the predetermined position P. FIG. 7 is a graph showing the point cloud amount on line L when the detection target object 7 exists on line L in FIG. 2 in a similar manner. As shown in FIG. 6, when there is no detection target object in the detection target area, the point cloud amount does not change. On the contrary, as shown in FIG. 7, when the detection target object 7 exists in the detection target area, the point cloud amount decreases at the location 9 of the "shadow" blocked by the detection target object 7. Also, as shown by the graph portion surrounded by the dashed-dotted line, the point cloud amount increases at the position of the outer surface of the detection target object 7 closer to the predetermined position P.

[0029] Therefore, if the decrease and increase in the point cloud amount can be accurately detected, it is possible to determine the presence of the detection target object 7. However, as described with reference to FIGS. 3 to 5, the density of the point cloud amount decreases as the distance from the sensor unit 1 increases. Therefore, in the present embodiment, as shown in FIG. 2, the detection target area is divided into a plurality of unit detection areas so that the point cloud amounts are approximately the same, and the point cloud amount is monitored for each unit detection area. Since the point cloud amounts within each individual unit detection area are approximately the same, it is possible to equally realize the determination regarding the increase and decrease of the point cloud amounts in all the unit detection areas, and it is possible to equalize the detection accuracy when viewed in terms of unit detection areas. As a result, it is possible to detect the "shadow" in terms of unit detection areas, and thus it is possible to detect the location of the "shadow" within the detection target area. And the location where the point cloud amount increases when the detection target object 7 exists is a unit detection area closer to the predetermined position P than the location of the "shadow". It is possible to determine the presence or absence of the detection target object 7 from the point cloud amount of this unit detection area. Also, it is possible to estimate the position and size of the detection target object 7 from the three-dimensional coordinates of each point.

[0030] Therefore, in this embodiment, the detection device 10 performs: (1) a division process of dividing a detection target area into a plurality of unit detection areas based on a predetermined division condition; (2) an existence determination process of determining the presence or absence of a detection target object in units of unit detection areas by detecting a reduced unit detection area in which the point cloud amount for each unit detection area based on the point cloud data satisfies a predetermined reduction condition; and (3) a detection target object estimation process of estimating the position and size of the detection target object using the point cloud of the reduced unit detection area and the point cloud of the unit detection area determined to have the detection target object present in the existence determination process.

[0031] 1. Division Process In the division process, the detection device 10 divides the detection target area into a plurality of unit detection areas based on a predetermined division condition in which the size of the unit detection area gradually increases as the distance from a predetermined position P increases when a predetermined infinite planar state is assumed. In this embodiment, the division based on the above-described division condition is executed by dividing the detection target area so that the point cloud amount for each unit detection area is within a reference point cloud amount range. The specific numerical range for the reference point cloud amount range may be set as appropriate, but hereinafter, a range of 7 to 11 with a median value of 9 is exemplified as the reference point cloud amount range.

[0032] Figs. 8 to 11 are diagrams showing an example of execution of division, focusing on the four areas in Fig. 8. In each figure, the point cloud amount of each area is displayed. As described above, the density of the point cloud of the detection target area is large on the near side (the lower side in Figs. 8 etc.) close to the predetermined position P and small on the far side (the upper side in Figs. 8 etc.). As a result of the division, as shown in Fig. 11, the detection target area can be divided into a plurality of unit detection areas such that the size of the unit detection area gradually increases as the distance from the predetermined position P increases.

[0033] Specifically, when dividing the detection target area, the detection device 10 repeatedly performs area division, enlargement, reduction, and integration so that the point cloud amount for each divided area is within the reference point cloud amount range. For example, FIG. 9 shows the states of enlargement and reduction for the upper and lower two areas on the left side shown in FIG. 8, respectively. FIG. 11 shows an example of dividing into unit detection areas by repeatedly performing division, etc. while allowing overlap of adjacent areas. Note that it is also possible to repeatedly perform division, etc. without allowing overlap of adjacent areas and divide into unit detection areas. For example, a configuration may be adopted in which each area in FIG. 10 is used as a unit detection area without performing division, etc. as shown in FIG. 11.

[0034] 2. Presence / Absence Judgment Process 2-1. Regarding Detection and Setting of Reduction Unit Detection Areas In the presence / absence judgment process, first, the detection device 10 determines, for each unit detection area, whether the point cloud amount of the unit detection area satisfies a predetermined reduction condition based on the point cloud data acquired by the sensor unit 1 at a predetermined acquisition cycle. Then, the detection device 10 detects the unit detection area that satisfies the reduction condition as a reduction unit detection area.

[0035] FIG. 12 is a diagram for explaining the detection of a reduction unit detection area. In FIG. 12, with the vertical axis representing the point cloud amount and the horizontal axis representing time, the transition of the point cloud amount for each acquisition cycle in one unit detection area of interest (unit detection area of interest) is graphed. The acquisition cycle of the point cloud data is, for example, 25 [ms]. FIG. 12 shows the transition of the point cloud amount in the unit detection area of interest based on the point cloud data acquired every 25 [ms]. Note that the acquisition cycle of the point cloud data is an example and may be longer or shorter than 25 [ms]. Also, in FIG. 12, the reference point cloud amount range is shown with hatching.

[0036] In this embodiment, the detection device 10 determines the reduction condition as "the point cloud quantity has continuously satisfied a predetermined reduction quantity condition for a predetermined time tB-IN or more". The predetermined time tB-IN is, for example, set to a length that allows the point cloud data to be acquired twice. Although FIG. 12 shows it as the interval of the acquisition timing of the point cloud data for easier understanding, more precisely, the predetermined time tB-IN is set to be equal to or greater than the length of one acquisition cycle and less than the length of two acquisition cycles, and the predetermined time tB-IN is measured through timing from the timing when the point cloud data was last acquired. Also, the reduction quantity condition can be set, for example, as "the point cloud quantity is less than a predetermined reduction determination quantity", etc. In the example of FIG. 12, for example, if the reduction determination quantity is set to 4, the point cloud quantity in the detection area of the target unit decreases to 3 at the acquisition timing of 175 [ms], and becomes 0 at the next acquisition timing of 200 [ms], satisfying the reduction condition. In the case of this example, the detection device 10 detects the detection area of the target unit as the reduction unit detection area at the acquisition timing of 200 [ms]. Note that the time length of the predetermined time tB-IN is not limited to the length that allows the point cloud data to be acquired twice, and can be set as appropriate.

[0037] Also, in the existence determination process of the present embodiment, the detection device 10 monitors the transition of the point cloud amount for the detected reduction unit detection area that is considered to satisfy the reduction condition, and determines whether the point cloud amount satisfies a predetermined return condition. For example, the detection device 10 determines the return condition as "the point cloud amount has continuously satisfied the predetermined return quantity condition for a predetermined time tB - OUT or more". The predetermined time tB - OUT is, for example, set to a length that allows the point cloud data to be acquired twice. Although shown as the interval of the acquisition timing of the point cloud data in FIG. 12 for clarity, more precisely, the predetermined time tB - OUT is set to be equal to or greater than the length of one acquisition cycle and less than the length of two acquisition cycles, and the predetermined time tB - OUT is measured via timing from the timing when the point cloud data was last acquired. Also, the return quantity condition can be set, for example, as "the point cloud amount is equal to or greater than a predetermined return determination quantity". Then, if the detection device 10 satisfies the return condition, the setting as the reduction unit detection area is released. In the example of FIG. 12, for example, if the return determination quantity is 5, the point cloud amount of the target unit detection area increases to 7 at the acquisition timing of 275 [ms], and becomes 10 at the next acquisition timing of 300 [ms], satisfying the return condition. In this example, the detection device 10 releases the setting as the reduction unit detection area for the target unit detection area at the acquisition timing of 300 [ms]. Note that the specific time length of the predetermined time tB - OUT can be set as appropriate. Also, this time length may be the same as the predetermined time tB - IN used for the determination of the reduction condition, or can be set to a different time length.

[0038] 2 - 2. Regarding the determination of the candidate unit detection area Subsequently, the detection device 10 determines a candidate unit detection area where the detection target object exists based on the setting of the reduction unit detection area. FIG. 13 is a diagram for explaining the determination of the candidate unit detection area, and among the unit detection areas obtained by dividing the detection target area, the reduction unit detection areas are shown with hatching. The example of FIG. 13 shows an example in which three reduction unit detection areas A11, A13, and A15 are set by the previous process.

[0039] In this embodiment, for each reduced unit detection area, the detection device 10 determines a unit detection area closer to a predetermined position P than the reduced unit detection area as a candidate unit detection area where a detection target object may exist. When a plurality of reduced unit detection areas are connected, the detection device 10 determines a unit detection area closer to the predetermined position P than the reduced unit detection area closest to the predetermined position P among the connected reduced unit detection areas as the candidate unit detection area. In the example of FIG. 13, for the reduced unit detection area A11, the unit detection area A21 is determined as the candidate unit detection area. Also, for the plurality of connected reduced unit detection areas A13 and A15, the unit detection area A23 is determined as the candidate unit detection area.

[0040] 2-3. Determination of the Existence of the Detection Target Object Subsequently, the detection device 10 determines whether a detection target object exists in the candidate unit detection area by using the point cloud amount of the candidate unit detection area based on the point cloud data. For example, when the point cloud amount of the candidate unit detection area increases beyond the upper limit of the reference point cloud amount range, the detection device 10 determines that a detection target object exists in the candidate unit detection area.

[0041] 3. Detection Target Object Estimation Process In the detection target object estimation process, the detection device 10 uses the three-dimensional coordinates of each point cloud of the reduced unit detection area detected as including the "shadow" part of the detection target object and the three-dimensional coordinates of each point cloud of the unit detection area determined to have the detection target object, extracts the objects existing in those reduced unit detection areas and unit detection areas, and estimates the position and size of the object as the position and size of the detection target object. At that time, the detection device 10 discriminates the type of the detection target object from the estimated size. For example, sizes are defined in advance for four types: a person, a two-wheeled vehicle, a regular automobile, and a large-sized automobile, and the type of the detection target object is discriminated from the estimated size of the detection target object. Note that the configuration is not limited to estimating the position and size of the detection target object, and it may be possible to estimate only the position of the detection target object or only the size of the detection target object.

[0042] 4. Determination of Reset State In order to appropriately determine the presence or absence of the object to be detected while suppressing the influence of environmental changes such as weather and time zone, the detection device 10 monitors whether a reset state in which the point cloud amount for each unit detection area should be reset has arrived. Then, when the reset state arrives, the detection device 10 re-executes the division of the detection target area based on the above-described division conditions.

[0043] In the present embodiment, the detection device 10 determines, for each unit detection area, whether the point cloud amount of the unit detection area satisfies a predetermined reset condition based on the point cloud data for each acquisition cycle acquired by the sensor unit 1. Then, as a result of performing this determination for each of all the unit detection areas, when the point cloud amount of any one of the unit detection areas satisfies the reset condition, the detection device 10 determines that the reset state has arrived.

[0044] Note that the configuration is not limited to determining the reset condition for each of all the unit detection areas, and a configuration for determining the reset condition for a specific unit detection area is also possible. That is, one or a plurality of unit detection areas for which the reset condition is to be determined may be set in advance as determination targets, and the reset condition may be determined for the unit detection areas that are the determination targets. For example, a specific one unit detection area is set as a determination target, and when the point cloud amount of the unit detection area that is the determination target satisfies the reset condition, it is determined that the reset state has arrived. The same applies when a plurality of unit detection areas are set as determination targets. For each of the plurality of unit detection areas set as determination targets, when the point cloud amount satisfies the reset condition, it is determined that the unit detection area that satisfies the reset condition has arrived at the reset state.

[0045] The reset condition at least includes, on the condition that "there is a unit detection area where the state where the point cloud amount does not satisfy the predetermined allowable condition continues for a predetermined reset determination time". In the present embodiment, for example, the allowable condition is that it is within the reference point cloud amount range. Then, the detection device 10 uses a lower limit side condition for detecting a unit detection area that no longer satisfies the allowable condition because the point cloud amount has fallen below the lower limit of the reference point cloud amount range, and an upper limit side condition for detecting a unit detection area that no longer satisfies the allowable condition because the point cloud amount has exceeded the upper limit of the reference point cloud amount range, to determine whether the reset condition is satisfied.

[0046] FIG. 14 is a diagram for explaining the lower limit side condition, and FIG. 15 is a diagram for explaining the upper limit side condition. In FIGS. 14 and 15, with the vertical axis representing the point cloud amount and the horizontal axis representing time, the transition of the point cloud amount for each acquisition period in a certain one unit detection area of interest (the unit detection area of interest) is graphed and shown.

[0047] The lower limit side condition can be set in advance, for example, as "the point cloud amount is greater than or equal to the reduction determination quantity and less than or equal to the lower limit of the reference point cloud amount range". That is, the detection device 10 detects a unit detection area where the point cloud amount has decreased to below the lower limit of the reference point cloud amount range, although it does not fall below the reduction determination quantity used in the detection of the reduction unit detection area, as satisfying the lower limit side condition. Then, after the point cloud amount has become below the lower limit of the reference point cloud amount range, when the state satisfying the lower limit side condition continues for the reset determination time in the unit detection area, the detection device 10 determines that the surrounding environment has changed and the reset state has arrived.

[0048] [[ID=ID=12]]For example, the point cloud amount of the unit detection area of interest shown in FIG. 14 is 7, which is the lower limit of the reference point cloud amount range, at the acquisition timing of 150 [ms]. After that acquisition period, the lower limit side condition is satisfied until the acquisition timing t3 when the reset determination time tA-D has elapsed. In this example, the detection device 10 determines that the reset state has arrived at the time of the acquisition timing t3. The specific time length of the reset determination time tA-D can be set as appropriate.

[0049] On the other hand, the upper limit side condition can be set in advance, for example, as "the point group amount exceeds the upper limit of the reference point group amount range". That is, the detection device 10 detects a unit detection area where the point group amount has increased to the upper limit or more of the reference point group amount range as satisfying the upper limit side condition. Then, after the point group amount becomes the upper limit or more of the reference point group amount range, when the state satisfying the upper limit side condition continues for the reset determination time in the unit detection area, the detection device 10 determines that the surrounding environment has changed and the reset state has arrived.

[0050] For example, the point group amount of the target unit detection area shown in FIG. 15 is 11, which is the upper limit of the reference point group amount range at the acquisition timing of 175 [ms], and satisfies the upper limit side condition until the acquisition timing t4 when the reset determination time tA-U elapses after the acquisition timing. In the case of this example, the detection device 10 determines that the reset state has arrived at the acquisition timing t4. The specific time length of the reset determination time tA-U may be set as appropriate. Also, the time length may be the same as the reset determination time tA-D in FIG. 14, or may be set to a different time length.

[0051] When the detection device 10 determines that the reset state has arrived, it re-executes the division based on the division condition to reset the unit detection area.

[0052] [Functional Configuration] FIG. 16 is a block diagram showing a functional configuration example of the detection device 10. As shown in FIG. 16, the detection device 10 includes an operation input unit 110, a display unit 120, a communication unit 130, a processing unit 150, and a storage unit 170, and is configured as a kind of computer system.

[0053] The operation input unit 110 is realized by an input device such as a button switch or a touch panel, etc., and outputs an operation signal corresponding to the operation input to the processing unit 150. The display unit 120 is realized by a display device such as an LCD (Liquid Crystal Display) or a touch panel, etc., and performs various displays according to the display signal from the processing unit 150. The communication unit 130 is realized by a wired or wireless communication device, and communicates with a given external device.

[0054] The processing unit 150 is realized by an arithmetic circuit such as a CPU (Central Processing Unit) or a control board including the arithmetic circuit, etc., and performs various arithmetic processes based on programs, data, etc. stored in the storage unit 170 to control the operation of the detection device 10.

[0055] In the present embodiment, the processing unit 150 includes a division unit 151, an existence determination unit 155, and a detection target object estimation unit 157. Each of these functional units may be an arithmetic processing block realized as software by executing a program, or may be a circuit block realized by a signal processing circuit. In the present embodiment, it will be described as an arithmetic processing block realized as software by the processing unit 150 executing a predetermined program.

[0056] The division unit 151 is a functional unit that executes division processing, executes division based on predetermined division conditions, and divides the detection target area into a plurality of unit detection areas. Further, the division unit 151 includes a reset state determination unit 153, and when the arrival of the reset state is determined by the reset state determination unit 153, it executes division based on the division conditions to reset the division of the unit detection area. The setting of each unit detection area divided by the division unit 151 is updated and held at any time as area setting data 173.

[0057] The existence determination unit 155 is a functional unit that executes existence determination processing, and determines the existence of the detection target object in units of unit detection areas by detecting a reduction unit detection area in which the point cloud amount for each unit detection area satisfies the reduction condition.

[0058] In this embodiment, the presence determination unit 155 counts the point cloud amount of each unit detection area for each acquisition period of the point cloud data 171 from the sensor unit 1. The counted point cloud amount is accumulated in the point cloud amount transition data 175 for each unit detection area. Then, the presence determination unit 155 detects a unit detection area that satisfies the reduction condition based on the counted point cloud amount as a reduction unit detection area, and updates the reduction unit detection area setting 177. Further, the presence determination unit 155 determines for each reduction unit detection area whether the reduction unit detection area satisfies the return condition based on the point cloud amount of the reduction unit detection area, deletes the setting of the reduction unit detection area that satisfies the return condition from the reduction unit detection area setting 177, and releases the setting. Then, the presence determination unit 155 determines a unit detection area closer to the predetermined position P than the reduction unit detection area as a candidate unit detection area, and determines whether a detection target object exists in the candidate unit detection area using the point cloud amount of the candidate unit detection area. When a plurality of reduction unit detection areas are connected, the presence determination unit 155 sets a unit detection area closer to the predetermined position P than the reduction unit detection area closest to the predetermined position P among the connected reduction unit detection areas as the candidate unit detection area. Then, when the point cloud amount of the candidate unit detection area increases beyond, for example, the upper limit of the reference point cloud amount range, the presence determination unit 155 determines that a detection target object exists in the candidate unit detection area.

[0059] The detection target object estimation unit 157 is a functional unit that executes a detection target object estimation process, and estimates the position and size of the detection target object using the point cloud of the reduction unit detection area and the point cloud of the unit detection area determined by the presence determination unit 155 to have a detection target object.

[0060] The storage unit 170 is realized by a storage medium such as an IC memory or a hard disk. The storage unit 170 stores in advance a program for operating the detection device 10 and realizing various functions of the detection device 10, data used during the execution of the program, etc., or temporarily stores them each time processing is performed. In the present embodiment, the storage unit 170 stores the point cloud data 171 input from the sensor unit 1 for each acquisition cycle, the area setting data 173, the point cloud amount transition data 175 for each unit detection area, and the reduction unit detection area setting 177.

[0061] The area setting data 173 defines the area range of each unit detection area obtained by dividing the detection target area for each unit detection area.

[0062] The point cloud amount transition data 175 for each unit detection area stores the point cloud amount for each unit detection area based on the point cloud data 171 of the acquisition cycle in association with the acquisition cycle of the sensor unit 1.

[0063] The reduction unit detection area setting 177 stores the setting of the reduction unit detection area by the presence / absence determination unit 155. When a new reduction unit detection area is detected by the presence / absence determination unit 155, the identification information of the corresponding unit detection area is added to the reduction unit detection area setting 177, and when the setting of the reduction unit detection area is cancelled, the identification information of the corresponding unit detection area is deleted from the reduction unit detection area setting 177.

[0064] [Processing flow] FIG. 17 is a flowchart showing the processing flow performed by the detection device 10. As shown in FIG. 17, in this processing, first, the division unit 151 executes division based on the division conditions to divide the detection target area into a plurality of unit detection areas and generates the area setting data 173 (step S1). Then, every time the acquisition cycle of the sensor unit 1 elapses (step S3: YES), the processing from step S5 onward is repeated using the acquired point cloud data 171.

[0065] That is, in step S5, the existence determination unit 155 counts the point cloud amount of each unit detection area. Then, the existence determination unit 155 determines, for each unit detection area, whether the reduction condition is satisfied based on the point cloud amount of the unit detection area. If there is a unit detection area that satisfies the reduction condition (step S7: YES), the existence determination unit 155 detects and sets the unit detection area as a reduction unit detection area (step S9). Further, the existence determination unit 155 determines, for each reduction unit detection area, whether the return condition is satisfied based on the point cloud amount of the reduction unit detection area. If there is a unit detection area that satisfies the return condition (step S11: YES), the setting as a reduction unit detection area is cancelled (step S13).

[0066] Subsequently, the existence determination unit 155 refers to the reduction unit detection area setting 177, and if there is an adjacent reduction unit detection area (step S15: YES), the unit detection area closer to the predetermined position P than the reduction unit detection area closest to the predetermined position P among the adjacent reduction unit detection areas is determined as a candidate unit detection area (step S17). If there is no adjacent reduction unit detection area (step S15: NO), the existence determination unit 155 determines, for each reduction unit detection area, the unit detection area closer to the predetermined position P than the reduction unit detection area as a candidate unit detection area (step S19). The existence determination unit 155 determines, for each candidate unit detection area determined in step S17 or step S19, whether the detection target object exists using the point cloud amount of the candidate unit detection area (step S21).

[0067] As a result of the determination in step S21, if it is determined that the detection target object exists (step S22: YSE), the detection target object estimation unit 157 estimates the position and size of the detection target object using the point cloud of the reduction unit detection area and the point cloud of the unit detection area where it is determined that the detection target object exists in step S21 (step S23). Then, the process proceeds to step S31.

[0068] On the other hand, when it is determined in step S21 that the object to be detected does not exist (step S22: NO), the reset state determination unit 153 determines, for each unit detection area, whether the reset condition is satisfied based on the point cloud amount of the unit detection area, and determines the arrival of the reset state (step S25). Then, when it is determined that the reset state has arrived (step S27: YES), the division unit 151 executes division based on the division condition to reset the division of the unit detection area and updates the area setting data 173 (step S29). After that, the process proceeds to step S31.

[0069] Then, in step S31, an end determination is made, and until it is determined to end (step S31: YES), the process returns to step S3.

[0070] As described above, according to the present embodiment, the detection target area can be divided into a plurality of unit detection areas such that the size of the unit detection area gradually increases as the distance from the predetermined position where laser irradiation and reception of the reflected wave are performed increases. Then, by detecting a reduced unit detection area in which the quantity of the point cloud satisfies a predetermined reduction condition based on the point cloud data acquired by the sensor unit 1 at the predetermined position P, the presence or absence of the object to be detected can be determined for each unit detection area. Further, the position and size of the object to be detected can be estimated using the point cloud of the reduced unit detection area and the point cloud of the unit detection area in which it is determined that the object to be detected exists.

Explanation of Reference Numerals

[0071] 1 Sensor unit, 10 Detection device, 150 Processing unit, 151 Division unit, 153 Reset state determination unit, 155 Presence / absence determination unit, 157 Object to be detected estimation unit, 170 Storage unit, 171 Point cloud data, 173 Area setting data, 175 Point cloud amount transition data for each unit detection area, 177 Reduced unit detection area setting, P Predetermined position, 5 Detection target area, 7 Object to be detected

Claims

1. A detection device that detects a detection target object existing in a detection target area based on point cloud data obtained by receiving a reflected wave of laser irradiation from a predetermined position, a dividing means for dividing the detection target area into a plurality of the unit detection areas based on a predetermined division condition in which the size of a unit detection area gradually increases as the distance from the predetermined position increases when a predetermined infinite planar state is assumed; an existence determination means for determining the presence or absence of the detection target object in units of the unit detection areas by detecting a reduced unit detection area in which the quantity of the point cloud for each unit detection area based on the point cloud data satisfies a predetermined reduction condition; A detection device comprising the above.

2. The presence / absence determination means determines, as a candidate unit detection area where the detection target object exists, the unit detection area closer to the predetermined position than the reduced unit detection area. The detection device according to Claim 1.

3. When a plurality of the reduced unit detection areas are connected, the presence / absence determination means determines, as the candidate unit detection area, the unit detection area closer to the predetermined position than the reduced unit detection area closest to the predetermined position among the connected reduced unit detection areas. The detection device according to Claim 2.

4. The presence / absence determination means determines whether or not the detection target object exists in the candidate unit detection area by using the quantity of the point cloud of the candidate unit detection area based on the point cloud data. The detection device according to Claim 2 or 3.

5. The reduction condition is that the quantity of the point cloud has continuously satisfied a predetermined reduction quantity condition for a predetermined time or more. The detection device according to any one of Claims 1 to 3.

6. The dividing means performs division based on the division condition in a predetermined reset state where the quantity of the point cloud for each unit detection area based on the point cloud data is concerned. The detection device according to any one of Claims 1 to 3.

7. When the dividing means satisfies a reset condition including at least that there exists a continuous unit detection area during a predetermined reset determination time in a state where the quantity of the point cloud does not satisfy a predetermined allowable condition, the dividing means determines that the reset state has arrived and performs division of the detection target area. The detection device according to Claim 6.

8. Detection target object estimation means for estimating the position and / or size of the detection target object by using the point cloud of the reduction unit detection area and the point cloud of the unit detection area determined by the presence / absence determination means to have the detection target object present therein. The detection device according to any one of claims 1 to 3, further comprising the same.

9. A detection method for detecting a detection target object existing in a detection target area based on point cloud data obtained by receiving a reflected wave of laser irradiation from a predetermined position, comprising: Dividing the detection target area into a plurality of the unit detection areas based on a predetermined division condition in which the size of the unit detection area gradually increases as the distance from the predetermined position becomes farther when a predetermined infinite planar state is assumed; Determining the presence or absence of the detection target object in units of the unit detection area by detecting a reduction unit detection area in which the quantity of the point cloud for each unit detection area based on the point cloud data satisfies a predetermined reduction condition; A detection method including the above.

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