Information processing device, information processing method, program and storage medium

Abstract

To correctly estimate the height of a ground surface even if a road surface is wet.SOLUTION: In an information processing device, acquisition means receives reflection light corresponding to an outgoing beam and acquires measurement data. Detection means detects a pair of areas where the symmetry of the measurement data is equal to or more than a prescribed level. Then, estimation means estimates the height of the midpoint between the pair of areas as the ground height.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a technique for acquiring information about the surroundings of a moving object. [Background technology]

[0002] Distance measuring devices have been known that irradiate a measurement object with light, detect the reflected light from the measurement object, and calculate the distance to the measurement object based on the time difference between the timing of irradiating the measurement object with light and the timing of detecting the reflected light from the measurement object. Patent Document 1 discloses a forward vehicle recognition device that changes a lighting pattern for projecting a light projection pattern depending on a detection state of the light projection pattern, and detects the distance and inclination of the forward vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-082750 A Summary of the Invention [Problem to be solved by the invention]

[0004] When detecting objects around a vehicle using a distance measuring device that uses laser light, such as a LIDAR, if the road surface is wet due to rain or other reasons, the amount of road surface data that can be measured by the LIDAR is significantly reduced, making it difficult to estimate the height of the ground.

[0005] The above is an example of a problem to be solved by the present invention. A main object of the present invention is to correctly estimate the ground height even when the road surface is wet. [Means for solving the problem]

[0006] The invention described in the claims is an information processing device comprising: an acquisition means for receiving reflected light corresponding to emitted light and acquiring measurement data; a detection means for detecting a pair of areas in which the symmetry of the measurement data is a predetermined level or higher; and an estimation means for estimating the height of the middle of the pair of areas as the ground height at the position of an object located in the upper area of ​​the pair of areas.

[0007] An invention described in another claim is an information processing method executed by an information processing device, and includes an acquisition step of receiving reflected light corresponding to the emitted light and acquiring measurement data, a detection step of detecting a pair of areas where the symmetry of the measurement data is a predetermined level or higher, and an estimation step of estimating the height of the middle of the pair of areas as the height of the ground at the position of an object located in the upper area of ​​the pair of areas.

[0008] The invention described in another claim is a program that causes a computer to function as an acquisition means that receives reflected light corresponding to the emitted light and acquires measurement data, a detection means that detects a pair of areas where the symmetry of the measurement data is a predetermined level or higher, and an estimation means that estimates the height of the middle of the pair of areas as the ground height at the position of an object located in the upper area of ​​the pair of areas. [Brief description of the drawings]

[0009] [Figure 1] 1 shows a schematic configuration of a lidar according to an embodiment. [Diagram 2] FIG. 13 is a diagram illustrating a method for estimating ground height. [Diagram 3] 13 is a flowchart of a ground height estimation process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In a preferred embodiment of the present invention, the information processing device comprises an acquisition means for receiving reflected light corresponding to the emitted light and acquiring measurement data, a detection means for detecting a pair of areas where the symmetry of the measurement data is a predetermined level or higher, and an estimation means for estimating the height of the center of the pair of areas as the ground level.

[0011] In the above information processing device, the acquisition means receives reflected light corresponding to the emitted light and acquires measurement data. The detection means detects a pair of regions in which the symmetry of the measurement data is equal to or greater than a predetermined level. The estimation means estimates the height of the center of the pair of regions as the ground height. This makes it possible to correctly estimate the ground height even when the road surface is wet.

[0012] In one aspect of the information processing device, the detection means detects at least a pair of regions in which the symmetry of the reflection intensity of the measurement data is equal to or greater than a predetermined value. In this aspect, the ground height can be estimated with high accuracy based on the symmetry of the reflection intensity.

[0013] In another aspect of the information processing device, the detection means detects a plurality of regions in which the reflection intensity is equal to or greater than a predetermined value, and detects a pair of regions that satisfy a range condition indicating a pair in the vertical direction from the plurality of regions. In this aspect, the ground height is estimated using the pair of regions that are paired in the vertical direction.

[0014] In another aspect of the information processing device, the acquiring means acquires point cloud information including the position and reflection intensity of each measurement point as the measurement data, and the detecting means detects an area including a predetermined number or more of measurement points having a reflection intensity equal to or greater than a predetermined value within a predetermined range as a mass area, and detects an upper mass area and a lower mass area that are paired in the vertical direction as the pair of areas. In this aspect, the pair of areas is detected using the mass areas of the measurement points.

[0015] In another aspect of the information processing device, the detection means determines a representative point of the upper block region and a representative point of the lower block region, and detects the upper block region and the lower block region whose representative points satisfy the range condition as the pair of regions. In this aspect, the pair of regions is detected using the representative point of each block region.

[0016] In another aspect of the information processing device, the estimation means calculates a difference between the newly estimated ground height and the previous ground height, and if the difference is equal to or greater than a predetermined allowable difference value, the newly estimated ground height is not adopted. In this aspect, abnormal values ​​caused by sudden noise or the like can be removed.

[0017] In another aspect of the information processing device, the acquisition means acquires point cloud information including the position and reflection intensity of each measurement point as the measurement data, and includes a removal means for removing measurement points located below the ground level from the measurement data. In this aspect, erroneously detected point clouds can be removed from the point cloud information using the estimated ground level.

[0018] In another aspect of the information processing device, the acquisition means acquires point cloud information including a position and a reflection intensity for each measurement point as the measurement data, and includes an object detection means for detecting an object using a measurement point located above the ground level among the measurement data. In this aspect, the accuracy of object detection can be improved by using the estimated ground level.

[0019] In another preferred embodiment of the present invention, an information processing method executed by an information processing device includes an acquisition step of receiving reflected light corresponding to emitted light and acquiring measurement data, a detection step of detecting a pair of areas where the symmetry of the measurement data is equal to or greater than a predetermined value, and an estimation step of estimating the height of the center of the pair of areas as the ground height. According to this information processing method, the ground height can be correctly estimated even when the road surface is wet.

[0020] In another preferred embodiment of the present invention, the program causes a computer to function as an acquisition means for receiving reflected light corresponding to emitted light and acquiring measurement data, a detection means for detecting a pair of regions where the symmetry of the measurement data is equal to or greater than a predetermined value, and an estimation means for estimating the height of the center of the pair of regions as the ground level. The above-mentioned information processing device can be realized by executing the program on a computer. The program can be stored in a storage medium and handled. EXAMPLES

[0021] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. [Device configuration] 1 shows a schematic configuration of a lidar 100 according to this embodiment. The lidar 100 is mounted on a vehicle that performs driving assistance such as autonomous driving. The lidar 100 irradiates a laser beam (also called "irradiated beam") in a predetermined angular range in the horizontal and vertical directions, and receives light (also called "reflected beam") that is reflected by an object and returns, thereby discretely measuring the distance from the lidar 100 to the object and generating point cloud information indicating the three-dimensional position of the object. The lidar 100 is installed so that the measurement range includes at least the forward direction of the vehicle on which it is mounted.

[0022] As shown in FIG. 1, the lidar 100 mainly includes a transmitter 1, a receiver 2, a beam splitter 3, a scanner 5, a piezoelectric sensor 6, a controller 7, and a memory 8.

[0023] The transmitter 1 is a light source that emits pulsed irradiation light toward the beam splitter 3. The transmitter 1 includes, for example, an infrared laser light emitting element. The transmitter 1 is driven based on a drive signal Sg1 supplied from the control unit .

[0024] The receiver 2 is, for example, an avalanche photodiode, generates a detection signal Sg2 corresponding to the amount of received light, and supplies the generated detection signal Sg2 to the controller .

[0025] The beam splitter 3 transmits the pulsed irradiation light emitted from the transmission unit 1. The beam splitter 3 also reflects the reflected light incident thereon via the scanner 5 towards the reception unit 2.

[0026] The scanner 5 is, for example, an electrostatically driven mirror (MEMS mirror), and the inclination (i.e., the angle of optical scanning) changes within a predetermined range based on a drive signal Sg3 supplied from the control unit 7. The scanner 5 reflects the illumination light that has passed through the beam splitter 3 toward the outside of the LIDAR 100, and also emits the reflected light that is incident from the outside of the LIDAR 100 toward the beam splitter 3. A point within the measurement range of the LIDAR 100 at which the illumination light is irradiated is also called a "measurement point."

[0027] The scanner 5 is provided with a piezoelectric sensor 6. The piezoelectric sensor 6 detects distortion caused by stress of a torsion bar that supports a mirror portion of the scanner 5. The piezoelectric sensor 6 supplies the generated detection signal Sg4 to the control unit 7. The detection signal Sg4 is used to detect the orientation of the scanner 5.

[0028] The memory 8 is composed of various volatile and non-volatile memories such as a RAM (Random Access Memory), a ROM (Read Only Memory), and a flash memory. The memory 8 stores a program required for the control unit 7 to execute a predetermined process. The memory 8 also stores various parameters referenced by the control unit 7. The memory 8 also stores point cloud information for the latest predetermined number of frames generated by the control unit 7.

[0029] The control unit 7 includes various processors such as a central processing unit (CPU) and a graphics processing unit (GPU). The control unit 7 executes a program stored in the memory 8 to perform a predetermined process. The control unit 7 is an example of a computer that executes a program. The control unit 7 is not limited to being realized by software according to a program, but may be realized by any combination of hardware, firmware, and software. The control unit 7 may be a user-programmable integrated circuit such as a field-programmable gate array (FPGA) or a microcontroller, or may be an application specific standard produce (ASSP), application specific integrated circuit (ASIC), or the like.

[0030] The control unit 7 functionally includes a transmission driving block 70, a scanner driving block 71, a point cloud information generation block 72, and a point cloud information processing block 73.

[0031] The transmission drive block 70 outputs a drive signal Sg1 that drives the transmission unit 1. The drive signal Sg1 includes information for controlling the emission time of a laser light-emitting element included in the transmission unit 1 and the emission intensity of the laser light-emitting element. The transmission drive block 70 controls the emission intensity of the laser light-emitting element included in the transmission unit 1 using the drive signal Sg1.

[0032] The scanner driving block 71 outputs a driving signal Sg3 for driving the scanner 5. The driving signal Sg3 includes a horizontal driving signal corresponding to the resonance frequency of the scanner 5 and a vertical driving signal for vertical scanning. In addition, the scanner driving block 71 detects the scanning angle of the scanner 5 (i.e., the emission direction of the irradiation light) by monitoring the detection signal Sg4 output from the piezoelectric sensor 6.

[0033] Based on the detection signal Sg2 supplied from the receiving unit 2, the point cloud information generation block 72 generates point cloud information indicating the distance and direction to the object irradiated with the irradiation light for each measurement point, with the lidar 100 as the reference point. In this case, the point cloud information generation block 72 calculates the time from when the irradiation light is emitted until the receiving unit 2 detects the reflected light as the time of flight of light. Then, the point cloud information generation block 72 generates point cloud information indicating the distance according to the calculated time of flight and the irradiation direction of the irradiation light corresponding to the reflected light received by the receiving unit 2 for each measurement point, and supplies the generated point cloud information to the point cloud information processing block 73. Hereinafter, the point cloud information obtained by one scan of all measurement points is referred to as one frame of point cloud information. The point cloud information is an example of measurement data.

[0034] Here, the point cloud information can be regarded as an image in which the measurement points are pixels and the distance indicated by each measurement point is the pixel value. In this case, the irradiation direction of the irradiation light at the elevation and depression angles of the vertically arranged measurement points is different, and the irradiation direction of the irradiation light at the horizontal angle of the horizontally arranged measurement points is different. Hereinafter, an XYZ coordinate system is defined with the horizontal direction (i.e., horizontal direction) of the image as the "Y axis," the vertical direction (i.e., height direction) of the image as the "Z axis," and the distance indicated by the pixel value (i.e., the distance from the LIDAR 100 in the depth direction) as the "X axis." Hereinafter, the XYZ coordinate system is considered to be a three-dimensional coordinate system with the position of the LIDAR 100 as the origin. In addition, the point cloud information includes information on the reflection intensity (i.e., the light receiving intensity at each measurement point) for each pixel.

[0035] The point cloud information generation block 72 may generate point cloud information from which data generated by erroneously detecting an object in the point cloud information (so-called false alarm data) has been removed. Hereinafter, measurement points corresponding to data generated by detecting an actual object are also referred to as "valid points." In this case, the point cloud information further includes flag information indicating whether each measurement point is a valid point or not.

[0036] The point cloud information processing block 73 estimates the height of the ground (hereinafter also referred to as "ground height") based on the point cloud information supplied from the point cloud information generation block 72. Specifically, the point cloud information processing block 73 estimates the ground height based on the point cloud information obtained from a measurement range including the front of the vehicle on which the lidar 100 is mounted.

[0037] In the above configuration, the receiving unit 2 is an example of an acquisition means, and the control unit 7 is an example of a detection means and an estimation means.

[0038] The point cloud information stored in the memory 8 may be output to, for example, a device that controls driving assistance such as automatic driving of a vehicle (also called a "driving assistance device"). In this case, the driving assistance device may be, for example, an ECU (Electronic Control Unit) of the vehicle, or an in-vehicle device such as a car navigation device electrically connected to the vehicle.

[0039] [Ground height estimation method] Next, a method for estimating the ground height will be described. When detecting and identifying objects around the vehicle using a lidar, the ground height is important information. For example, even if the lidar detects the roof of a preceding vehicle as an object, without information on the ground height, it is not possible to distinguish whether the object is the roof of the vehicle or the ground. For this reason, the control unit 7 estimates the ground height based on point cloud information measured by the lidar.

[0040] However, when the road surface (ground) is wet due to rainfall or the like, the specular reflection from the road surface is large, which significantly reduces the number of measurement points obtained by the lidar 100, making it difficult to estimate the ground height. Therefore, in this embodiment, the control unit 7 estimates the ground height by utilizing the specular reflection of a reflector from the road surface.

[0041] Fig. 2(A) shows an example of an image 10A of the front of the vehicle and a point cloud display 20A obtained by the lidar 100. Note that the example of Fig. 2(A) is an image taken in front of a vehicle equipped with the lidar 100, in which the road surface is wet due to rainfall or the like. The image 10A is an image taken of the front of the vehicle equipped with the lidar 100, and includes a boundary line 11 indicating the lane in which the vehicle is traveling, and a direction sign 12 installed on the road. In addition, since the road surface is wet, the image 10A shows a mirror image 13 of the direction sign 12, which appears as a mirror reflection on the wet road surface.

[0042] The point cloud display 20A displays the point cloud information obtained by the LIDAR 100. This point cloud information is obtained by removing data (false alarm data) generated by erroneous detection of the above-mentioned object from all point cloud information generated by the LIDAR 100. In FIG. 2(A), the point cloud area is displayed in a darker (closer to black) color as the reflection intensity increases. The point cloud display 20A includes a horizon 21. In the point cloud display 20A, the area beyond the horizon 21 is a ground area 22 including the sky, and the area in front of the horizon 21 is a road area 23. For convenience, an auxiliary line 23x indicating the traveling direction of the vehicle is displayed in dashed line in the road area 23.

[0043] The point cloud display 20A includes a point cloud 25 at a position corresponding to the direction sign 12 included in the image 10A. Because the direction sign 12 is a reflector with high reflectivity, the direction sign 12 is detected as a point cloud 25 with a large reflection intensity value. The point cloud display 20A also includes a point cloud 26 corresponding to the mirror image 13 in the image 10A. The point cloud 26 is detected as an area with a large reflection intensity value created by the direction sign 12 being mirror-reflected on the wet road surface.

[0044] FIG. 2(B) shows another example of an image 10B of the front of the vehicle and a point cloud display 20B obtained by the lidar 100. The example of FIG. 2(B) also shows a state in which the road surface is wet due to rainfall or the like. The image 10B is an image captured of the front of the vehicle equipped with the lidar 100, and includes a boundary line 11 indicating the lane in which the vehicle is traveling, and a preceding vehicle 15. A reflector 15a is provided at the rear of the preceding vehicle 15. Since the road surface is wet, the image 10B shows a mirror image 16 of the reflector 15a, which appears as a specular reflection on the wet road surface.

[0045] The point cloud display 20B displays the point cloud information obtained by the lidar 100. The point cloud display 20B also shows the point cloud after removing false alarm data from all point cloud information. In FIG. 2(B) as well, the point cloud area is displayed in a darker color the higher the reflection intensity. As in FIG. 2(A), the point cloud display 20B includes a horizon 21, a ground area 22, and a road area 23, and an auxiliary line 23x indicating the traveling direction of the vehicle is displayed in the road area 23.

[0046] The point cloud display 20B includes a point cloud 27 at a position corresponding to the preceding vehicle 15 included in the image 10B. The preceding vehicle 15 is detected as a point cloud 27 with a high reflection intensity value. Among the point cloud 27 corresponding to the preceding vehicle 15, the point cloud 27a corresponding to the reflector 15a in particular has a high reflection intensity. The point cloud display 20B also includes a point cloud 28 at a position corresponding to the mirror image 16 in the image 10B. The point cloud 28 is detected as an area with a high reflection intensity value created by the specular reflection of the reflector 15a on the wet road surface.

[0047] In this way, when the road surface is wet, highly reflective objects (reflectors) such as the direction sign 12 and the reflector 15a are specularly reflected on the road surface, and are detected as areas with high reflection intensity values ​​generated by specular reflection (hereinafter also referred to as "specular reflection areas"). Here, the highly reflective objects and their specular reflection areas are in a line-symmetrical relationship with respect to the horizontal line indicating the ground height. Specifically, if the ground height at the position where the direction sign 12 is installed in the image 10A of FIG. 2(A) is indicated as "G1," the ground height G1 is located in the middle in the height direction between the point cloud 25 corresponding to the direction sign 12 and the point cloud 26 corresponding to the mirror image 13 of the direction sign 12, as shown in the point cloud display 20A. Similarly, if the ground height at the position of the leading vehicle 15 in the example image 10B of Figure 2(B) is indicated as "G2," then, as shown in the point cloud display 20B, the ground height G2 is located in the middle in the vertical direction between the point cloud 27a corresponding to the reflector 15a and the point cloud 28 corresponding to the mirror image 16 of the reflector 15a.

[0048] Therefore, the control unit 7 of the LIDAR 100 detects a pair of areas where the symmetry in the height direction of the three-dimensional coordinate values ​​is equal to or greater than a predetermined value, specifically, a pair of areas where the symmetry in the reflection intensity is equal to or greater than a predetermined value, from the point cloud information after the false alarm data has been removed. In more detail, the control unit 7 detects data that is large in the reflection intensity value and pairs in the height direction, and estimates the midpoint height of those data as the ground height at that position. This makes it possible to correctly estimate the ground height even if the road surface is wet and the amount of point cloud information that can be measured by the LIDAR is reduced.

[0049] [Ground height estimation process] 3 is a flowchart of a ground height estimation process performed by the LIDAR 100. This process is realized by the control unit 7 shown in FIG. 1 executing a program prepared in advance.

[0050] First, the control unit 7 generates point cloud information after removing false alarm data based on the detection signal Sg2 input from the receiving unit 2, and detects a point cloud (hereinafter referred to as "clump data") that is a cluster of measurement points whose reflection intensity is equal to or greater than a predetermined threshold (step S11). Specifically, the control unit 7 detects, as the cluster data, a point cloud constituted by a predetermined number or more of measurement points whose reflection intensity is equal to or greater than a threshold gathered within a predetermined range in the aforementioned XYZ coordinate system. Note that the above-mentioned predetermined threshold and predetermined number are determined in advance by experiments, etc.

[0051] Next, the control unit 7 detects a pair of data (hereinafter also referred to as "paired data") that are aligned in the height direction (Z-axis direction) from among the multiple block data obtained (step S12). Hereinafter, of the upper and lower block data that make up the paired data, the upper block data will be referred to as the "upper block data" and the lower block data will be referred to as the "lower block data." Note that block data is an example of a block region, upper block data is an example of an upper block region, and lower block data is an example of a lower block region.

[0052] Specifically, the control unit 7 first obtains a representative point for each block data. For example, the control unit 7 assumes one block data of the obtained multiple block data as upper block data, and sets the center of the point group constituting the upper block data in the depth direction (X-axis direction) and the left-right direction (Y-axis direction) and the lowest point in the up-down direction (Z-axis direction) as the representative point of the upper block data. Next, the control unit 7 assumes all the remaining block data as lower block data, and sets the center of the point group constituting each lower block data in the depth direction and the left-right direction and the highest point in the up-down direction as the representative point of each lower block data.

[0053] Then, when the representative point of the upper block data and the representative point of the lower block data belong to a predetermined XYZ range condition in the XYZ coordinate system, the control unit 7 judges the upper block data and the lower block data to be paired data. Note that the predetermined XYZ range condition is, for example, predetermined within an error range in the depth direction (X-axis direction) and left-right direction (Y-axis direction), and within a predetermined height range in the height direction (Z-axis direction). In this way, the control unit 7 sequentially assumes all block data to be upper block data, and detects paired data from multiple block data by searching for lower block data that is paired with it.

[0054] Next, the control unit 7 corrects the size of the lower block data (step S13). Specifically, the control unit 7 uses the upper block data to remove the blurred portion included in the lower block data. As described above, the lower block data is an area where reflectors such as direction signs and reflectors are specularly reflected on a wet road surface, and the surrounding area tends to be detected as a larger area that is expanded than the original reflector. The part that is expanded more than the original reflector is called the blurred portion. If the lower block data includes a blurred portion, an error occurs in the estimated ground height due to the size of the blurred portion in the height direction. Therefore, the control unit 7 corrects the size of the lower block data.

[0055] Usually, among the paired data detected in step S12, the upper block data is detected as a direct reflection by the original reflector, so there is little error in size. Therefore, the control unit 7 removes the blurred portion from the lower block data based on the reflection intensity value and size of the upper block data, and corrects the size of the lower block data. For example, the control unit 7 may remove the peripheral area of ​​the lower block data so that the size of the lower block data is approximately equal to that of the upper block data. In addition, the control unit 7 may correct the size of the lower block data in consideration of the reflection intensity value of the lower block data being smaller than the reflection intensity value of the upper block data.

[0056] Next, the control unit 7 estimates the height of the center between the upper block data and the lower block data included in the paired data as the ground height at the depth direction (X-axis direction) position (step S14). For example, the control unit 7 calculates the ground height H as follows. H = {(Z coordinate of the representative point of the upper block data) + (Z coordinate of the representative point of the lower block data)} / 2 Then, the control unit 7 outputs the calculated ground height H, and ends the ground height processing.

[0057] Basically, the control unit 7 may continuously execute the above height estimation process while the vehicle is traveling. However, when only road signs such as direction signs are used as reflectors, the control unit 7 may refer to map data, etc. to detect points where road signs exist, and execute the above process pinpoint-by-pinpoint for each point.

[0058] As described above, according to this embodiment, the ground height can be estimated with high accuracy by utilizing the specular reflection of the reflector even when the road surface is wet due to rainfall, etc. In addition, this method has the advantage that, if paired data can be detected, there is no need for object identification processing to determine whether the original reflector is a direction signboard or a reflector, and therefore the ground height can be estimated efficiently.

[0059] [Variations] Next, modified examples of the above height estimation process will be described. The following modified examples can be applied in appropriate combination.

[0060] (Variation 1) In the above height estimation process, when the ground height H is calculated in step S14, the control unit 7 may determine whether the calculated ground height H is an abnormal value by using a ground height obtained in the past. Specifically, the control unit 7 calculates the difference between the calculated ground height H and the value of the ground height H' obtained in the past. Then, the control unit 7 adopts the obtained ground height H if the calculated difference is equal to or smaller than a predetermined allowable difference value, and does not adopt the obtained ground height if the difference is equal to or larger than the allowable difference value. This makes it possible to prevent other processes from being performed by adopting an abnormal ground height obtained due to sudden noise or the like.

[0061] (Variation 2) In step S12 of the height estimation process, the control unit 7 may detect paired data using different XYZ range conditions for each type of reflector used. As can be seen from Figs. 2(A) and 2(B), the height direction distance between the upper block data and the lower block data constituting the paired data differs between the case where a direction signboard is used as a reflector and the case where a vehicle reflector is used. Therefore, the XYZ range conditions used when detecting paired data in step S12 may be prepared for each type of reflector. More specifically, the XYZ range conditions may be determined for each type of reflector, taking into account the height at which that type of reflector is generally present.

[0062] (Variation 3) In the above height estimation process, the ground height at a point where a reflector such as a direction sign or a vehicle reflector is present can be estimated, but the ground height at a point where no reflector is present cannot be estimated. Therefore, the control unit 7 may obtain the ground height at a point where no reflector is present by interpolation based on the estimated ground heights at a plurality of points and the installation conditions of the lidar 100 on the vehicle.

[0063] [Processing using ground height] Next, a process using the ground height estimated by the above method will be described. According to this embodiment, even if the road surface is wet, the ground height can be estimated, so that the following processes can be performed with high accuracy.

[0064] (false alarm data removal) The estimated ground height can be used to remove false alarm data. As described above, removing false alarm data means removing a point cloud generated by erroneously detecting an object from all point clouds measured by the LIDAR 100. Specifically, the control unit 7 may remove, from all point clouds generated by the LIDAR 100, a point cloud that appears below the estimated ground height as false alarm data. In this case, the control unit 7 is an example of a removal means.

[0065] (Object detection / obstacle detection) The estimated ground height can be used for object detection or obstacle detection. Specifically, the control unit 7 can determine that a point cloud that is above the estimated ground height, among the point clouds after removing false alarm data, is a point cloud that constitutes an object or an obstacle. In this case, the control unit 7 is an example of an object detection means.

[0066] (Object Identification) The estimated ground height can be used for object identification. When an object is identified based on a photographed image in front of the vehicle or a point cloud measured by a lidar, the success or failure of the identification result can be determined using a constraint condition based on the estimated ground height. For example, since the height of a person is about 2 m at most, when the object to be identified is a pedestrian, a constraint condition that the height is within 2 m from the ground is used. The control unit 7 uses the estimated ground height to determine whether the height of an object determined to be a pedestrian by object identification is within 2 m, and if the height is 2 m or more, it can determine that the identification result is incorrect. It should be noted that, not only for pedestrians, but also for vehicles and other objects, if the general height is known, the height can be used as a constraint condition to prevent erroneous identification.

[0067] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above-mentioned embodiments. Various modifications that can be understood by a person skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. In other words, the present invention naturally includes various modifications and corrections that a person skilled in the art could make in accordance with the entire disclosure, including the claims, and the technical ideas. In addition, the disclosures of the above cited patent documents and the like are incorporated herein by reference. [Explanation of symbols]

[0068] 1. Transmitter 2. Receiving section 3 Beam splitter 5. Scanner 6 Piezo Sensor 7 Control section 8. Memory 100 Rider

Claims

1. an acquisition means for receiving reflected light corresponding to the emitted light and acquiring measurement data; A detection means for detecting a pair of regions in which the symmetry of the measurement data is equal to or greater than a predetermined value; an estimation means for estimating the height of the center of the pair of regions as the height of the ground at a position of an object located in the upper region of the pair of regions; An information processing device comprising:

2. The information processing apparatus according to claim 1 , wherein the detection means detects at least a pair of regions in which the symmetry of the reflection intensity of the measurement data is equal to or greater than a predetermined value.

3. 3. The information processing apparatus according to claim 2, wherein the detection means detects a plurality of areas in which the reflection intensity is equal to or greater than a predetermined value, and detects, from the plurality of areas, a pair of areas that satisfy a range condition indicating that the areas are paired in the up-down direction.

4. The acquisition means acquires point cloud information including a position and a reflection intensity for each measurement point as the measurement data, The information processing device according to claim 3, wherein the detection means detects an area that includes a predetermined number or more of measurement points within a predetermined range where the reflection intensity is equal to or greater than a predetermined value as a mass area, and detects an upper mass area and a lower mass area that are paired in the vertical direction as the pair of areas.

5. 5. The information processing apparatus according to claim 4, wherein said detection means determines a representative point of said upper block region and a representative point of said lower block region, and detects, as said pair of regions, an upper block region and a lower block region whose representative points satisfy said range condition.

6. 6. The information processing device according to claim 1, wherein the estimation means calculates a difference between a newly estimated ground height and a previous ground height, and if the difference is equal to or greater than a predetermined allowable difference value, the newly estimated ground height is not adopted.

7. The acquisition means acquires point cloud information including a position and a reflection intensity for each measurement point as the measurement data, 4. The information processing apparatus according to claim 2, further comprising a removing unit that removes measurement points located below the ground level from the measurement data.

8. The acquisition means acquires point cloud information including a position and a reflection intensity for each measurement point as the measurement data, 4. The information processing apparatus according to claim 2, further comprising an object detection unit that detects an object using measurement points located above the ground level in the measurement data.

9. An information processing method executed by an information processing device, an acquisition step of receiving reflected light corresponding to the emitted light and acquiring measurement data; a detection step of detecting a pair of regions in which the symmetry of the measurement data is equal to or greater than a predetermined value; an estimation step of estimating the height of the center of the pair of regions as the height of the ground at the position of an object located in the upper region of the pair of regions; An information processing method comprising:

10. an acquisition means for receiving reflected light corresponding to the emitted light and acquiring measurement data; A detection means for detecting a pair of regions in which the symmetry of the measurement data is equal to or greater than a predetermined value; an estimation means for estimating the height of the center of the pair of regions as the height of the ground at a position of an object located in the upper region of the pair of regions; A program that makes a computer function as a

11. A storage medium storing the program according to claim 10.

Images