DETECTION APPARATUS AND DETECTION METHOD

Abstract

To realize a mechanism capable of determining the presence or absence of a detection target object throughout an entire detection target area based on point cloud data acquired by receiving reflected waves of a laser beam emitted from a specified position. [Solution] A detection device 10 detects a detection target object existing within a detection target area based on point cloud data acquired by receiving a reflected wave of a laser irradiation from a predetermined position. The detection device 10 includes a division unit 151 that divides the detection target area into a plurality of unit detection areas based on a predetermined division condition in which the size of a unit detection area gradually increases as the distance from a predetermined position increases when a predetermined infinite plane state is assumed, and a presence / absence determination unit 155 that determines the presence / absence of a detection target object for each unit detection area by detecting a reduced unit detection area in which the quantity of points in each unit detection area based on point cloud data 171 satisfies a predetermined reduction condition.

Description

[Technical field]

[0001] The present invention relates to a detection device that detects a detection target object within a detection target area. [Background technology]

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

[0003] [Patent Document 1] JP 2023-180614 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when detecting an object using a sensor such as LiDAR, point cloud data is acquired by receiving reflected waves of laser irradiation from the installation position of the sensor, so that, in principle, the further away from the installation position of the sensor, the smaller the point cloud density becomes. When the detection target area becomes wider, a single sensor cannot detect with high resolution the object to be detected within the detection target area, especially an object moving at a position far from the installation position of the sensor. Therefore, it is often necessary to install multiple sensors in various locations while overlapping the areas covered by each sensor depending on the size of the detection target area. However, when multiple sensors are installed and operated, the installation cost and maintenance cost of the sensors increase. Therefore, there has been a demand for a detection system for the detection target object to be configured with as few sensors as possible. To this end, when focusing on a single sensor, a mechanism is required that can determine the presence or absence of a detection target object in as wide an area as possible covered by the single sensor based on point cloud data acquired by receiving reflected waves of laser irradiation from a specific position where the single sensor is installed.

[0005] The problem that the present invention aims to solve is to realize a mechanism that can determine the presence or absence of a detection target object throughout the entire detection area based on point cloud data obtained by receiving reflected waves of a laser irradiation from a specified position. [Means for solving the problem]

[0006] A first invention for solving the above problem is a detection device that detects a detection target object present within a detection target area based on point cloud data acquired by receiving reflected waves of a laser irradiation from a predetermined position, and includes a division means (e.g., division unit 151 in FIG. 16) that divides the detection target area into a plurality of 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 plane state is assumed, and a presence / absence determination means (e.g., presence / absence determination unit 155 in FIG. 16) that determines the presence or absence of the detection target object on a unit detection area basis by detecting reduced unit detection areas in which the quantity of points 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 so that the size of the unit detection area gradually increases as the distance from a predetermined position increases when a predetermined infinite plane state is assumed, and reduced unit detection areas in which the number of point clouds satisfies a predetermined reduction condition are detected, thereby making it possible to determine the presence or absence of a detection target object on a unit detection area basis.

[0008] A second invention, in the above invention, is a detection device, wherein the presence / absence determination means determines the unit detection area closer to the specified position than the reduced unit detection area as a candidate unit detection area in which the object to be detected is present.

[0009] A third invention is a detection device in which, in the above invention, the presence / absence determination means determines, when a plurality of the reduced unit detection areas are adjacent, the unit detection area that is closer to the specified position than the reduced unit detection area that is closest to the specified position among the adjacent reduced unit detection areas, as the candidate unit detection area.

[0010] A fourth invention is a detection device in which, in the above invention, the presence / absence determination means determines whether or not the detection target object exists in the candidate unit detection area using the quantity of points 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. According to the third invention, when a plurality of reduction unit detection areas are adjacent, 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. According to the fourth invention, it can be determined whether or not a detection target object exists in the candidate unit detection area.

[0012] A fifth invention, in the above invention, is the detection device, wherein the reduction condition is that the number of points in the cloud continues to satisfy a predetermined reduction quantity condition for a predetermined period of time or more.

[0013] According to the fifth aspect of the present invention, a unit detection area in which the number of points in the cloud continues to satisfy the reduction quantity condition for a predetermined period of time or more can be detected as a reduced unit detection area.

[0014] A sixth invention, in the above-mentioned invention, is a detection device, wherein the dividing means executes division based on the division condition when the quantity of point clouds for each unit detection area based on the point cloud data is in a predetermined reset state.

[0015] According to the sixth aspect of the present invention, in a predetermined reset state based on the quantity of points in a unit detection area, division based on the division condition can be executed.

[0016] A seventh invention is a detection device in which, in the above invention, the division means determines that the reset state has occurred and performs division of the detection target area when a reset condition is satisfied that at least includes a condition that a unit detection area exists in which a state in which the quantity of point cloud does not satisfy a predetermined tolerance condition continues for a predetermined reset judgment time.

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

[0018] An eighth invention is a detection device according to the above invention, further comprising a detection target object estimation means (e.g., detection target object estimation unit 157 in Figure 16) that estimates a position and / or 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 in which the presence / absence determination means has determined that the detection target object exists.

[0019] According to the eighth aspect of the present invention, the position and size of a detection target object can be estimated from the point cloud of a reduced unit detection area and the point cloud of a unit detection area in which it is determined that the detection target object is present.

[0020] A ninth invention is a detection method for detecting a target object present within a detection target area based on point cloud data acquired by receiving reflected waves of a laser irradiation from a predetermined position, the detection method including: dividing 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 the predetermined position increases when a predetermined infinite plane state is assumed; and detecting reduced unit detection areas in which the quantity of points for each unit detection area based on the point cloud data satisfies a predetermined reduction condition, thereby determining the presence or absence of the target object for each unit detection area.

[0021] According to the ninth aspect of the present invention, it is possible to realize a detection method that provides the same effects as those of the first aspect of the present invention. [Brief description of the drawings]

[0022] [Figure 1] FIG. 13 is a schematic diagram showing an application example of the detection device. [Diagram 2] Schematic diagram showing the detection target area from above. [Diagram 3] FIG. 4 is a diagram showing an example of point cloud data. [Figure 4] FIG. 11 is a diagram showing another example of point cloud data. [Diagram 5] FIG. 11 is a diagram showing another example of point cloud data. [Figure 6] 1A and 1B are diagrams for explaining the principle of determining whether or not a detection target object exists; [Figure 7] 13 is another diagram for explaining the principle of determining whether or not a detection target object exists. FIG. [Figure 8] FIG. [Figure 9] FIG. 11 is another diagram showing an example of division execution. [Figure 10] FIG. 11 is another diagram showing an example of division execution. [Figure 11] FIG. 11 is another diagram showing an example of division execution. [Figure 12] 11A and 11B are diagrams for explaining detection of a reduction unit detection area; [Figure 13] 11A and 11B are diagrams for explaining determination of candidate unit detection areas; [Figure 14] FIG. 13 is a diagram for explaining a lower limit condition. [Figure 15] FIG. 13 is a diagram for explaining an upper limit condition. [Figure 16] FIG. 2 is a block diagram showing an example of a functional configuration of a detection device. [Figure 17] 4 is a flowchart showing a flow of processing performed by a detection device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0024] Fig. 1 is a schematic diagram showing an application example of a detection device 10 in this embodiment, showing an area 5 on a road 3 that is 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 this embodiment detects detection target objects 7, such as vehicles and pedestrians, that exist in the detection target area 5 based on a positioning result by a sensor unit 1 installed at a high position on the side of a road 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 reflected waves of laser irradiation from a predetermined installed position P. The sensor unit 1 calculates distance from the reflection time until the reflected waves are received, measures the position of an object by referring to the irradiation direction, etc., and acquires the positioning result as point cloud data of 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 cyclically scans the laser light within a sector-shaped range in 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 points constituting the point cloud data decreases as it moves away from the predetermined position P. Here, in FIG. 2, the range including the detection target area 5 is partitioned so that the number of points in each grid (hereinafter also referred to as the "point cloud amount") is approximately the same. Since the density of the points decreases as it moves away from the predetermined position P, the partition of the grid is narrower on the near side as viewed from the predetermined position P and wider on the far side. In other words, the distance between adjacent points is greater on the far side of the detection target area 5 than on the near side, and the detection accuracy (resolution) of the detection target object decreases accordingly. Therefore, a mechanism is required to detect the detection target object without missing it even on the far side of the detection target area 5 far from the predetermined position P.

[0027] [detail] 3 to 5 are top views of examples of point cloud data acquired by the sensor unit 1. The predetermined position where the sensor unit 1 is installed is a position on the lower end side of the detection area, slightly to the left of the center, and at a predetermined height from the ground. The point cloud data in FIG. 3 to FIG. 5 is point cloud data acquired in a scene where a vehicle, which is a detection target object, travels from the back side of the detection target area to the front side so as to approach the sensor unit 1. One point obtained for one irradiation of laser light and reception of reflected waves corresponds to one white point. In FIG. 3 to FIG. 5, the detection target object and its "shadow" are shown surrounded by a double line consisting of a white line and a black dashed line superimposed thereon. The "shadow" referred to here is an area where the laser light does not reach because it is blocked by the detection target object as seen from the sensor unit 1. As shown in Figs. 3 to 5, when the state of the detection target object in the detection target area changes from the absence to the presence of the detection target object, the laser light that would have been irradiated to the ground if the detection target object did not exist is irradiated and reflected by the detection target object, so that the point cloud amount at the outer surface part of the detection target object closer to the sensor unit 1 increases compared to when the detection target object does not exist. In addition, the presence of the detection target object creates a "shadow" behind the detection target object as seen from the sensor unit 1. The "shadow" is something that did not exist when the detection target object did not exist. In the "shadow" area, the laser light is blocked by the detection target object and does not reach it, so the point cloud amount decreases compared to when the detection target object does not exist. As shown in Figs. 3 to 5, it is possible to determine the presence or absence of a "shadow" even if it is far from the sensor unit 1. The detection device 10 uses such an increase or decrease in the point cloud amount to determine the presence or absence of a detection target object in the detection target area.

[0028] 6 and 7 are diagrams for explaining the principle of the presence / absence judgment of the detection target object in this embodiment. FIG. 6 is a graph of the point cloud amount on the line L in FIG. 2 along the line L from the side of the 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 of the point cloud amount on the line L in FIG. 2 when the detection target object 7 exists on the line L in the same manner. As shown in FIG. 6, when the detection target object does not exist in the detection target area, the point cloud amount does not change. In contrast, 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 in the graph portion surrounded by the dashed 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 or increase in the point cloud amount can be detected accurately, 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 this embodiment, as shown in Fig. 2, the detection target area is divided into a plurality of unit detection areas so that the point cloud amount is approximately the same, and the point cloud amount is monitored for each unit detection area. Since the point cloud amount in each unit detection area is approximately the same, it is possible to equally determine the increase or decrease in the point cloud amount in all unit detection areas, and it is possible to level out the detection accuracy when viewed in unit detection area units. This makes it possible to detect a "shadow" in unit detection area units, and thus to detect the location of the "shadow" in the detection target area. And, when the detection target object 7 exists, the location where the point cloud amount increases is the 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. It is also 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 that divides the detection target area into a plurality of unit detection areas based on predetermined division conditions, (2) a presence / absence determination process that determines the presence or absence of a detection target object on a unit detection area basis by detecting reduced unit detection areas in which the point cloud amount for each unit detection area based on the point cloud data satisfies predetermined reduction conditions, and (3) a detection target object estimation process that estimates 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 in which it is determined that the detection target object exists in the presence / absence determination process.

[0031] 1. Split processing 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 plane state is assumed. In this embodiment, the detection target area is divided so that the point cloud amount for each unit detection area falls within the reference point cloud amount range, thereby executing division based on the above-mentioned division condition. The specific range of quantities as the reference point cloud amount range may be set appropriately, but 7 to 11 with a median of 9 will be exemplified below as the reference point cloud amount range.

[0032] 8 to 11 are diagrams showing an example of division, focusing on the four areas in FIG. 8. In each diagram, the point cloud amount for each area is displayed. As described above, the density of the point cloud in the detection target area is high on the front side (lower side in FIG. 8, etc.) close to the predetermined position P, and is low on the back side (upper side in FIG. 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 so 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 divides, enlarges, reduces, and integrates the area so that the point cloud amount for each divided area falls within the reference point cloud amount range. For example, FIG. 9 shows the two upper and lower areas on the left side shown in FIG. 8 after they have been enlarged and reduced. FIG. 11 shows an example of division into unit detection areas by repeating division, etc., while allowing adjacent areas to overlap. It is also possible to divide into unit detection areas by repeating division, etc., without allowing adjacent areas to overlap. For example, a configuration may be used in which each area in FIG. 10 is a unit detection area, without dividing as in FIG. 11.

[0034] 2. Presence / absence determination process 2-1. Detection and setting of reduction unit detection area In the presence / absence determination process, the detection device 10 first determines whether the point cloud amount of each unit detection area satisfies a predetermined reduction condition, based on the point cloud data acquired at a predetermined acquisition cycle by the sensor unit 1. Then, the detection device 10 detects the unit detection area that satisfies the reduction condition as a reduced unit detection area.

[0035] FIG. 12 is a diagram for explaining detection of a reduced unit detection area. In FIG. 12, the vertical axis represents the point cloud amount and the horizontal axis represents time, and a graph is shown showing the transition of the point cloud amount for each acquisition period in one unit detection area of ​​interest (target unit detection area). The acquisition period of the point cloud data is, for example, 25 [ms]. FIG. 12 shows the transition of the point cloud amount in the target unit detection area based on the point cloud data acquired every 25 [ms]. Note that the acquisition period 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 amount continues for a predetermined time tB-IN or more and satisfies a predetermined reduction quantity condition." The predetermined time tB-IN is, for example, a length that allows the point cloud data to be acquired twice. In FIG. 12, for ease of understanding, the interval between the timings of acquiring the point cloud data is shown, but more accurately, the predetermined time tB-IN is set to be equal to or longer than one acquisition cycle and shorter than two acquisition cycles, and the predetermined time tB-IN is measured by clocking from the timing of the most recent acquisition of the point cloud data. In addition, the reduction quantity condition can be set, for example, as "the point cloud amount is less than a predetermined reduction determination quantity." In the example of FIG. 12, for example, if the reduction determination quantity is 4, the point cloud amount of the target unit detection area is reduced to 3 at the acquisition timing of 175 [ms] and is 0 at the next acquisition timing of 200 [ms], thereby satisfying the reduction condition. In this example, the detection device 10 detects the target unit detection area as a reduction unit detection area at the acquisition timing of 200 [ms]. The length of the predetermined time tB-IN is not limited to a length that allows the point cloud data to be acquired twice, and may be set appropriately.

[0037] In the presence / absence determination process of this embodiment, the detection device 10 monitors the subsequent transition of the point cloud amount for the reduction unit detection area that has been detected as satisfying 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 continues for a predetermined time tB-OUT or more and satisfies a predetermined return quantity condition". The predetermined time tB-OUT is, for example, a length that allows the point cloud data to be acquired twice. In FIG. 12, for ease of understanding, the interval between the timing of acquiring the point cloud data is shown, but more accurately, the predetermined time tB-OUT is set to be equal to or longer than one acquisition cycle and shorter than two acquisition cycles, and the predetermined time tB-OUT is measured via clocking from the timing of acquiring the point cloud data immediately before. In addition, 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 return condition is satisfied, the detection device 10 cancels the setting as the reduction unit detection area. 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 cancels the setting of the target unit detection area as the reduced unit detection area at the acquisition timing of 300 [ms]. Note that the specific time length of the predetermined time tB-OUT may be set appropriately. Also, the time length may be the same as the predetermined time tB-IN used to determine the reduction condition, or it may be set to a different time length.

[0038] 2-2. Determining candidate unit detection areas Next, the detection device 10 determines a candidate unit detection area in which the detection target object exists based on the setting of the reduced 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 reduced unit detection areas are shown hatched. The example of Fig. 13 shows an example in which three reduced unit detection areas A11, A13, and A15 are set by the previous processing.

[0039] In this embodiment, the detection device 10 determines, for each reduced unit detection area, a unit detection area closer to the predetermined position P than the reduced unit detection area, as a candidate unit detection area in which a detection target object exists. When multiple reduced unit detection areas are adjacent, the detection device 10 determines, as a candidate unit detection area, a unit detection area closer to the predetermined position P than the reduction unit detection area closest to the predetermined position P among the adjacent reduced unit detection areas. 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 multiple adjacent reduced unit detection areas A13 and A15, the unit detection area A23 is determined as the candidate unit detection area.

[0040] 2-3. Determining the presence or absence of a detection target object Next, the detection device 10 determines whether or not a detection target object exists in a 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 a 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. Detected 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" of the detection target object and the three-dimensional coordinates of each point cloud of the unit detection area in which the detection target object is determined to exist, extracts an object existing in the reduced unit detection area and the unit detection area, 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 determines the type of the detection target object from the estimated size. For example, the sizes of four types of objects, namely, a person, a two-wheeled vehicle, a normal automobile, and a large automobile, are defined in advance, and the type of the detection target object is determined 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 is also possible to estimate only the position of the detection target object or only the size of the detection target object.

[0042] 4. Determining the reset state In order to appropriately determine the presence or absence of a detection target object while suppressing the influence of environmental changes such as weather and time of day, the detection device 10 monitors whether a reset state has occurred in which the point cloud amount for each unit detection area should be reset. When the reset state has occurred, the detection device 10 re-executes division of the detection target area based on the above-mentioned division condition.

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

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

[0045] The reset condition at least includes the condition that "there is a unit detection area in which the point cloud amount does not satisfy a predetermined tolerance condition for a predetermined reset judgment time." In this embodiment, for example, being within a reference point cloud amount range is set as the tolerance condition. Then, the detection device 10 judges whether the reset condition is satisfied using a lower limit side condition for detecting a unit detection area that does not satisfy the tolerance condition because the point cloud amount falls below the lower limit of the reference point cloud amount range, and an upper limit side condition for detecting a unit detection area that does not satisfy the tolerance condition because the point cloud amount exceeds the upper limit of the reference point cloud amount range.

[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 Fig. 14 and Fig. 15, the vertical axis represents the point cloud amount and the horizontal axis represents time, and the transition of the point cloud amount for each acquisition cycle in one unit detection area of ​​interest (unit detection area of ​​interest) is shown in a graph.

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

[0048] For example, the point cloud amount of the target unit detection area shown in Fig. 14 is 7 points, which is the lower limit of the reference point cloud amount range, at the acquisition timing of 150 [ms], and satisfies the lower limit side condition from the acquisition cycle until acquisition timing t3 at which the reset determination time tA-D has elapsed. In this example, the detection device 10 determines that the reset state has arrived at the acquisition timing t3. The specific time length of the reset determination time tA-D may be set appropriately.

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

[0050] For example, the point cloud amount of the target unit detection area shown in FIG. 15 is 11 points, which is the upper limit of the reference point cloud amount range, at the acquisition timing of 175 [ms], and satisfies the upper limit side condition from the acquisition timing until acquisition timing t4 at which the reset determination time tA-U has elapsed. In 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 appropriately. In addition, 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] Then, when the detection device 10 determines that the reset state has been reached, it re-executes division based on the division condition and resets the unit detection area.

[0052] [Function configuration] Fig. 16 is a block diagram showing an example of a functional configuration 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 type of computer system.

[0053] The operation input unit 110 is realized by an input device such as a button switch or a touch panel, 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, and performs various displays corresponding to a 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, for example, by an arithmetic circuit such as a CPU (Central Processing Unit) or a control board including the arithmetic circuit, and performs various types of arithmetic processing based on programs, data, etc. stored in the memory unit 170 to control the operation of the detection device 10.

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

[0056] The division unit 151 is a functional unit that executes a division process, and executes division based on a predetermined division condition to divide the detection target area into a plurality of unit detection areas. The division unit 151 also includes a reset state determination unit 153, and when the reset state determination unit 153 determines that a reset state has occurred, executes division based on the division condition to reset the division of the unit detection areas. The settings of each unit detection area divided by the division unit 151 are updated as needed and held as area setting data 173.

[0057] The presence / absence determining unit 155 is a functional unit that executes presence / absence determining processing, and determines the presence / absence of a detection target object for each unit detection area by detecting a reduced unit detection area in which the point cloud amount for each unit detection area satisfies a reduction condition.

[0058] In this embodiment, the presence / absence 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 / absence determination unit 155 detects the unit detection area that satisfies the reduction condition based on the counted point cloud amount as a reduced unit detection area, and updates the reduced unit detection area setting 177. Also, the presence / absence determination unit 155 determines whether the reduction unit detection area satisfies the return condition based on the point cloud amount of the reduction unit detection area for each reduction unit detection area, deletes the setting of the reduced unit detection area that satisfies the return condition from the reduced unit detection area setting 177, and cancels the setting. Then, the presence / absence determination unit 155 determines the unit detection area closer to the predetermined position P than the reduction unit detection area as a candidate unit detection area, and determines whether the detection target object exists in the candidate unit detection area using the point cloud amount of the candidate unit detection area. When multiple reduction unit detection areas are adjacent, the presence / absence determination unit 155 determines, as a candidate unit detection area, a unit detection area that is closer to the predetermined position P than the reduction unit detection area that is closest to the predetermined position P among the adjacent reduction unit detection areas. Then, when the point cloud amount of a candidate unit detection area increases beyond the upper limit of a reference point cloud amount range, for example, the presence / absence determination unit 155 determines that a detection target object is present 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 reduced unit detection area and the point cloud of the unit detection area in which the presence / absence determination unit 155 has determined that a detection target object exists.

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

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

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

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

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

[0066] Next, the presence / absence 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), it determines a 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 as a candidate unit detection area (step S17). If there is no adjacent reduction unit detection area (step S15: NO), the presence / absence determination unit 155 determines, for each reduction unit detection area, a unit detection area closer to the predetermined position P than the reduction unit detection area as a candidate unit detection area (step S19). For each candidate unit detection area determined in step S17 or step S19, the presence / absence determination unit 155 determines whether or not a detection target object exists using the point cloud amount of the candidate unit detection area (step S21).

[0067] If it is determined in step S21 that a detection target object exists (step S22: YES), the detection target object estimation unit 157 estimates 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 in which it is determined in step S21 that the detection target object exists (step S23). Then, the process proceeds to step S31.

[0068] On the other hand, if it is determined in step S21 that the detection target object does not exist (step S22: NO), the reset state determination unit 153 determines whether the reset condition is satisfied for each unit detection area based on the point cloud amount of the unit detection area, and determines whether the reset state has arrived (step S25). Then, if 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). Then, the process proceeds to step S31.

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

[0070] As described above, according to this embodiment, the detection target area can be divided into a plurality of unit detection areas so that the size of the unit detection area gradually increases as the distance from the predetermined position where the laser irradiation and the reflected wave are received increases. Then, by detecting a reduced unit detection area in which the number of points satisfies a predetermined reduction condition based on the point cloud data acquired by the sensor unit 1 at the predetermined position P, it is possible to determine the presence or absence of a detection target object in each unit detection area. In addition, the position and size of the detection target object 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 detection target object exists. [Explanation of symbols]

[0071] 1 sensor unit, 10 detection device, 150 processing unit, 151 division unit, 153 reset state determination unit, 155 presence / absence determination unit, 157 detection target object estimation unit, 170 storage unit, 171 point cloud data, 173 area setting data, 175 point cloud amount transition data by unit detection area, 177 reduction unit detection area setting, P specified position, 5 detection target area, 7 detection target object

Claims

1. A detection device that detects a detection target object present within a detection target area based on point cloud data acquired by receiving a reflected wave of a laser irradiation from a predetermined position, a dividing means for dividing the detection target area into a plurality of unit detection areas based on a predetermined dividing condition in which, assuming a predetermined infinite plane state, the size of the unit detection area gradually increases as the distance from the predetermined position increases; a presence / absence determination means for determining the presence or absence of the detection target object in each unit detection area by detecting a reduced unit detection area in which the quantity of point clouds for each unit detection area based on the point cloud data satisfies a predetermined reduction condition; Equipped with The presence / absence determining means determining, as a candidate unit detection area in which the detection target object exists, the unit detection area that is closer to the predetermined position than the reduced unit detection area, and when a plurality of the reduced unit detection areas are adjacent to each other, the unit detection area that is closer to the predetermined position than the reduced unit detection area that is closest to the predetermined position among the adjacent reduced unit detection areas; determining that the detection target object exists in the candidate unit detection area when a quantity of points in the candidate unit detection area based on the point cloud data satisfies a predetermined increase condition; To carry out Detection device.

2. The reduction condition is that the number of points in the point cloud satisfies a predetermined reduction quantity condition for a predetermined period of time or more. The detection device of claim 1 .

3. A detection device that detects a detection target object present within a detection target area based on point cloud data acquired by receiving a reflected wave of a laser irradiation from a predetermined position, a dividing means for dividing the detection target area into a plurality of unit detection areas based on a predetermined dividing condition in which, assuming a predetermined infinite plane state, the size of the unit detection area gradually increases as the distance from the predetermined position increases; a presence / absence determination means for determining the presence or absence of the detection target object in each unit detection area by detecting a reduced unit detection area in which the quantity of point clouds for each unit detection area based on the point cloud data satisfies a predetermined reduction condition; Equipped with the dividing means, when a reset state is reached in which the quantity of point clouds for each unit detection area based on the point cloud data should be reset by dividing the detection target area again, divides the detection target area again; Detection device.

4. the dividing means determines that the reset state has occurred and executes division of the detection target area when a reset condition is satisfied that at least includes a condition that the unit detection area exists in which a state in which the number of points in the cloud does not satisfy a predetermined tolerance condition continues for a predetermined reset determination time. The detection device of claim 3.

5. a detection target object estimation means for estimating a position and / or a size of the detection target object by using the point cloud of the reduced unit detection area and the point cloud of the unit detection area in which it has been determined by the presence / absence determination means that the detection target object is present; The detection device according to any one of claims 1 to 4, further comprising:

6. A detection method for detecting a detection target object present in a detection target area based on point cloud data acquired by receiving a reflected wave of a laser irradiation from a predetermined position, comprising: Dividing 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 the predetermined position increases when a predetermined infinite plane state is assumed; detecting a reduced unit detection area in which a quantity of point clouds for each unit detection area based on the point cloud data satisfies a predetermined reduction condition, thereby determining the presence or absence of the detection target object for each unit detection area; Including, The determining step comprises: determining, as a candidate unit detection area in which the detection target object exists, the unit detection area that is closer to the predetermined position than the reduced unit detection area, and when a plurality of the reduced unit detection areas are adjacent to each other, the unit detection area that is closer to the predetermined position than the reduced unit detection area that is closest to the predetermined position among the adjacent reduced unit detection areas; determining that the detection target object exists in the candidate unit detection area when a quantity of points in the candidate unit detection area based on the point cloud data satisfies a predetermined increase condition; Including, Detection method.

7. A detection method for detecting a detection target object present in a detection target area based on point cloud data acquired by receiving a reflected wave of a laser irradiation from a predetermined position, comprising: Dividing 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 the predetermined position increases when a predetermined infinite plane state is assumed; detecting a reduced unit detection area in which a quantity of point clouds for each unit detection area based on the point cloud data satisfies a predetermined reduction condition, thereby determining the presence or absence of the detection target object for each unit detection area; Including, The dividing step includes, when a reset state occurs in which a quantity of point clouds for each unit detection area based on the point cloud data should be reset by dividing the detection target area again, dividing the detection target area again. Detection method.

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