JP2024015755A - Target device, adjustment method, adjustment system and adjustment program - Google Patents

Abstract

An object of the present invention is to reduce restrictions on the arrangement of a target device used for adjusting a lidar device. A target device according to the present disclosure is used for adjusting a lidar device. A target device according to the present disclosure is characterized in that it includes a sphere that reflects measurement light irradiated by the lidar device. [Selection diagram] Figure 8

Description

The present invention relates to a target device, an adjustment method, an adjustment system, and an adjustment program.

Patent Document 1 describes a target device used for axis adjustment of a camera device and a lidar device mounted on a vehicle.

JP 2021-85679 Publication

Since the target section of Patent Document 1 is configured in a flat plate shape, it is not possible to measure the target device from the side. Therefore, when using the target device described in Patent Document 1, there are restrictions on the arrangement of the target device.

An object of the present invention is to alleviate constraints on the placement of target devices.

One form of the present invention for achieving the above object is a target device used for adjusting a lidar device, and the target device includes a sphere that reflects measurement light irradiated by the lidar device.

Other problems disclosed in the present application and methods for solving the problems will be made clear by the detailed description section and the drawings.

According to the present invention, restrictions on the arrangement of target devices can be alleviated.

FIG. 1 is an explanatory diagram of the adjustment system 1 of the first embodiment. FIG. 2 is an explanatory diagram of the target device 30 used in the first embodiment. FIG. 3 is a flow diagram of the adjustment method according to the first embodiment. FIG. 4 is an explanatory diagram showing the relationship between the orthogonal coordinate system (x, y, z) and the polar coordinate system (θ, φ, d). FIG. 5A is an explanatory diagram of N point data forming the point group data of the sphere 31. FIG. 5B is an explanatory diagram of the angle difference δ _i and the distance difference r _i . FIG. 6A is an explanatory diagram of a curve D(r) showing the surface of the sphere 31. FIG. 6B is an explanatory diagram of the relationship between the curve D(r) and N coordinates (r _i , d _i ). FIG. 7 is an explanatory diagram of the adjustment system 1 of the second embodiment. FIG. 8 is an explanatory diagram of the target device 30 used in the second embodiment. FIG. 9 is a flow diagram of the adjustment method according to the second embodiment. FIGS. 10A and 10B are explanatory diagrams of the installation situation of the target device 30 of the second embodiment. FIG. 11 is a flow diagram of time adjustment. FIG. 12 is an explanatory diagram of the time adjustment value Δt.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In addition, in the following description, the same or similar configurations may be given the same reference numerals and redundant descriptions may be omitted.

===First embodiment===
<Configuration>
FIG. 1 is an explanatory diagram of the adjustment system 1 of the first embodiment.

The adjustment system 1 is a system for adjusting the lidar device 10 by having the lidar device 10 measure the target device 30 . Note that the adjustment of the lidar device 10 includes, for example, adjusting the arrangement of the lidar device 10, adjusting the output result of the lidar device 10, and the like. The adjustment system 1 includes a lidar device 10, a control device 20, and a target device 30.

The lidar device 10 detects a three-dimensional shape within the measurement area by emitting measurement light toward the measurement area and receiving reflected light (reflected light when the measurement light is reflected from an object within the measurement area). (LiDAR; Light Detection and Ranging, Laser Imaging Detection and Ranging). For example, the LIDAR device 10 detects the time from irradiating the measurement light to receiving the reflected light to detect the reflection point (the point where the measurement light is reflected and the reflected light is generated; the surface of the object). Measure the distance to. Furthermore, the lidar device 10 generates point cloud data by emitting measurement light toward the measurement area at a predetermined resolution and receiving reflected light from a plurality of points in the measurement area. Point cloud data is a collection of point data. The point data is data (coordinate data) indicating coordinates (here, three-dimensional coordinates). The point cloud data of the measurement area includes point data indicating the coordinates of points (reflection points) on the surface of the object.

The control device 20 is a device that controls the adjustment system 1. The control device 20 is composed of one or more computers. The control device 20 acquires point cloud data from the lidar device 10 and performs adjustment processing to be described later. That is, the control device 20 corresponds to a computer that processes point group data (coordinate data) of the lidar device 10. The control device 20 includes an arithmetic device and a storage device (not shown). The computing device is, for example, a computing processing device such as a CPU or a GPU. A part of the arithmetic device may be constituted by an analog arithmetic circuit. A storage device is a device that is composed of a main storage device and an auxiliary storage device, and stores programs and data. Various processes are executed by the arithmetic unit executing the programs stored in the storage device. In the figure, functional blocks of various processes performed by the control device 20 are shown. The control device 20 includes a measuring section 21 and an adjusting section 22. The measurement unit 21 detects objects within the measurement area based on the point cloud data of the lidar device 10. For example, the measurement unit 21 extracts objects such as people and cars within the measurement area based on the point cloud data, and detects the positions of the objects (people, cars, etc.). The adjustment unit 22 performs adjustment processing of the rider device 10. The adjustment process will be described later.

FIG. 2 is an explanatory diagram of the target device 30 used in the first embodiment.
The target device 30 is a device used to adjust the lidar device 10, and is a device that indicates a reference position. The target device 30 includes a sphere 31 and a support member 32.

The sphere 31 is a member (target portion) for indicating a reference position. As described later, the center (center of gravity) of the sphere 31 becomes the reference position. The sphere 31 is configured to reflect the measurement light emitted by the lidar device 10. A reflective film or the like may be applied to the surface of the sphere 31. The sphere 31 has a diameter of about 30 cm, for example, but is not limited to this size. The size of the sphere 31 needs to be such that the lidar device 10 can measure the surface of the sphere 31 at a plurality of points.

If the sphere 31 is placed within the measurement area of the lidar device 10, the lidar device 10 can measure point cloud data for a hemisphere of the sphere 31 from any position and from any angle. Therefore, by calculating the center coordinates (reference position) of the sphere 31 based on the point cloud data for the hemisphere of the sphere 31, it is possible to calculate the reference position of the target part from any position and from any angle. be. For this reason, in the present embodiment, the target section indicating the reference position is formed of the sphere 31. Note that a method for calculating the center coordinates (reference position) of the sphere 31 based on the point group data for a hemisphere will be described later.

The support member 32 is a member for supporting the sphere 31. Here, the support member 32 supports the sphere 31 so that the center of the sphere 31 is at a predetermined height. The support member 32 has a base portion 33 and a support column 34. The pedestal is a part that serves as a pedestal on which the target device 30 is installed. The support column 34 is a part that holds the sphere 31 at a predetermined height. However, the support member 32 is not limited to such a configuration.

The support member 32 has a lower reflectance of measurement light than the sphere 31. This makes it easier to extract the point cloud data of the sphere 31 from the point cloud data of the entire measurement area. An absorption film that absorbs measurement light may be provided on the surface of the support member 32.

As will be described below, the target device 30 will be installed and removed in the measurement area. Therefore, it is desirable that the target device 30 has a structure that is easy to transport. For this reason, it is desirable that the support member 32 is foldable. Further, it is preferable that the sphere 31 is an inflatable structure such as an air bag.

<Adjustment method>
FIG. 3 is a flow diagram of the adjustment method according to the first embodiment. The processes of S102 to S105 in the figure are realized by the arithmetic unit forming the control device 20 executing the adjustment program.

First, an operator installs the target device 30 at a predetermined position (S101). The target device 30 will be installed within the measurement area of the lidar device 10. Note that not all parts of the target device 30 need to be installed within the measurement area of the lidar device 10, and it is sufficient that at least the sphere 31 is installed within the measurement area of the lidar device 10. The operator inputs the position (coordinates) where the target device 30 is installed into the control device 20 . Thereby, the control device 20 can acquire the center coordinates of the sphere 31 of the target device 30.

Next, the adjustment unit 22 of the control device 20 causes the lidar device 10 to measure the measurement area (S102). Since the target device 30 is installed in the measurement area, measurement light is emitted from the lidar device 10 toward the sphere 31, and the lidar device 10 receives reflected light from the sphere 31, thereby measuring the surface of the sphere 31. The coordinates of multiple points at will be measured. The lidar device 10 outputs point cloud data of the measurement area, including point cloud data for a hemisphere of the sphere 31, to the control device 20.

Next, the adjustment unit 22 extracts point cloud data of the sphere 31 (point cloud data for a hemisphere) from the point cloud data of the measurement area (S103). Note that the point cloud data of the sphere 31 can be extracted from the point cloud data of the measurement area by well-known object recognition processing. Note that the point data constituting the point group data of the sphere 31 indicates the coordinates of points on the surface of the sphere 31.

Next, the adjustment unit 22 calculates the center coordinates (reference position) of the sphere 31 based on the point group data of the sphere 31 (S104). Note that a method for calculating the center coordinates (reference position) of the sphere 31 based on the point group data of the sphere 31 will be described later.

Next, the adjustment unit 22 performs processing for adjusting the lidar device 10 based on the center coordinates (reference position) of the sphere 31 (S105). For example, in S105, the adjustment unit 22 calculates an adjustment value (offset value; rider (equivalent to adjustment data regarding adjustment of the device) is calculated, and the adjustment value is stored in a storage unit (not shown).

After the adjustment processing in S105 (after the target device 30 is removed from the measurement area), the measurement unit 21 of the control device 20 corrects the coordinates of the point cloud data acquired from the lidar device 10 using the adjustment values, thereby adjusting the lidar device. The point cloud data indicated by the coordinates relative to the origin of 10 can be adjusted to the point cloud data indicated by the coordinates relative to the origin on the map.

<About the method for calculating the center coordinates of the sphere 31 1>
A method for calculating the center coordinates (reference position) of the sphere 31 based on the point group data of the sphere 31 will be explained. In the following explanation, it is assumed that the coordinates indicated by the N point data forming the point group data for the hemisphere of the sphere 31 are (x _i , y _i , z _i ) (i=1, 2, 3, . . . N). The coordinates of the N pieces of point data each indicate the coordinates of a point on the surface of the sphere 31.

First, the adjustment unit 22 calculates the average value of the coordinates indicated by the N pieces of point data. Here, the coordinates obtained by averaging the N point data are (x _ave , y _ave , z _ave ).

Next, the adjustment unit 22 calculates the center coordinates (x _c , y _c , z _c ) of the sphere 31 based on the following equation. Note that R in the following equation is the radius of the sphere 31 and is a known value.

<About the method for calculating the center coordinates of the sphere 31 2>
In the calculation method described above, there is a possibility that the center coordinates of the sphere 31 are calculated to be closer to the lidar device 10 side. Further, in the calculation method described above, the radius of the sphere 31 needs to be known. Therefore, the center coordinates of the sphere 31 may be calculated using the calculation method described below.

FIG. 4 is an explanatory diagram showing the relationship between the orthogonal coordinate system (x, y, z) and the polar coordinate system (θ, φ, d). Note that the origin in the figure corresponds to the position of the lidar device 10.
First, the adjustment unit 22 converts point data indicating coordinates in an orthogonal coordinate system (x, y, z) to point data indicating coordinates in a polar coordinate system (θ, φ, d) shown in the figure. Note that θ corresponds to a horizontal angle coordinate, φ corresponds to a vertical angle coordinate, and d corresponds to a distance coordinate (distance to the lidar device 10). In the following explanation, it is assumed that the coordinates indicated by the N point data forming the point group data for the hemisphere of the sphere 31 are (θ _i , φ _i , d _i ) (i=1, 2, 3, . . . N).

Next, the adjustment unit 22 calculates the average value of the coordinates indicated by the N point data. Here, the coordinates obtained by averaging the N point data are (θ _ave , φ _ave , d _ave ).

FIG. 5A is an explanatory diagram of N point data forming the point group data of the sphere 31. Each point in the figure indicates a measurement point measured by the lidar device 10 at a predetermined resolution (for example, 0.1 degree resolution). Further, the black circles in the figure indicate positions (coordinates) on the surface of the sphere 31, and indicate positions (coordinates) indicated by N point data forming the point group data of the sphere 31. As shown in the figure, when the resolution of the lidar device 10 is uniform, the coordinates of points on the hemisphere are measured almost symmetrically when viewed from the lidar device 10. Therefore, the coordinates θ _ave and the coordinates φ _ave indicate the coordinates of the center (center of gravity) of the sphere 31. In other words, when the center coordinates of the sphere 31 are (θ _c , φ _c , d _c ), the coordinate θ _c can be calculated as θ _c = θ _ave , and the vertical angle coordinate φ _c can be calculated as φ _c = φ _ave . can. Note that since the lidar device 10 measures the surface of the hemisphere of the sphere 31 closer to the lidar device 10, the coordinate d _ave indicates a coordinate closer to the lidar device 10 than the center coordinate of the sphere 31. It will not be the center coordinate d _c . Therefore, next, a method for calculating the coordinate _dc of the distance to the center (center of gravity) of the sphere 31 will be explained.

FIG. 5B is an explanatory diagram of the angle difference δ _i and the distance difference r _i .

Next, the adjustment unit 22 calculates the angle difference δ _i from the center (center of gravity) of the sphere 31 and the distance difference r _i for the N point data (θ _i , φ _i , d _i ) based on the following equation. and are calculated respectively. Thereby, the adjustment unit 22 can acquire N coordinates (r _i , d _i ).

FIG. 6A is an explanatory diagram of a curve D(r) showing the surface of the sphere 31. When the coordinates of the distance from the center (center of gravity) of the sphere 31 are d _c , the distance difference from the center (center of gravity) of the sphere 31 is r, and the radius of the sphere 31 is R, as shown in FIG. 6A, the sphere 31 A curve D(r) representing the surface of can be expressed as follows.

FIG. 6B is an explanatory diagram of the relationship between the curve D(r) and N coordinates (r _i , d _i ). The solid line in the figure shows the curve D(r) which is the equation of the surface of the sphere 31. Further, the points in the figure indicate coordinates (r _i , d _i ) obtained from N point data.
Based on the N coordinates (r _i , d _i ), the adjustment unit 22 determines a distance d _c and radius such that the N coordinates (r _i , d _i ) plausibly fit the curve D(r). Find R. In other words, the adjustment unit 22 calculates the maximum likelihood estimation value of the distance d _c and radius R in the curve D(r) based on the N coordinates (r _i , d _i ) (N coordinates (r _i , d _i ). The maximum likelihood estimates of the distance d _c and the radius R can be obtained by nonlinear simple regression analysis. Note that when the radius R is known, the adjustment unit 22 substitutes a known value for R in the formula representing the curve D(r), and then calculates the radius R based on the N coordinates (r _i , d _i ). Then, the distance d _c at which the curve D(r) most likely fits these N coordinates (r _i , d _i ) may be determined.

Finally, the adjustment unit 22 converts the coordinates (θ _c , φ _c , d _c ) of the center (center of gravity) of the sphere 31 shown in the polar coordinate system to the orthogonal coordinate system, thereby converting the center coordinates (x _c , y _c , z _c ).

Note that the center coordinates (x _c , y _c , z _c ) of the sphere 31 may be calculated without using the polar coordinate system. For example, when the center coordinates of the sphere 31 are (x _c , y _c , z _c ) and the radius of the sphere 31 is R (known), the coordinates (x, y, z) of the surface of the sphere 31 are It is possible to utilize the fact that the equation (x−x _c ) ² +(y−y _c ) ² +(z−z _c ) ² =R ² holds true. _In this case _, the adjustment unit 22 adjusts the N coordinates ₍ x _i , y _i , z _i ) is the equation of the spherical surface (x _i - x _c ) ² + (y _i - y _c ) ² + (z _i - z _c ) ^{2 =} The center coordinates (x _c , y _{c ,} z _c ) of the sphere 31 are calculated by finding the maximum likelihood estimates of c , y _c , and z _c .

===Second embodiment===
<Configuration>
FIG. 7 is an explanatory diagram of the adjustment system 1 of the second embodiment.
Also in the second embodiment, the adjustment system 1 includes a lidar device 10, a control device 20, and a target device 30. Although two lidar devices 10 are shown in the figure, the number of lidar devices 10 may be one, or two or more. In the figure, two lidar devices 10 are shown measuring the T-junction from different angles. However, the location where the lidar device 10 is installed is not limited to T-junctions and intersections.

FIG. 8 is an explanatory diagram of the target device 30 used in the second embodiment.
Also in the second embodiment, the target device 30 includes a sphere 31 and a support member 32. In the second embodiment, the target device 30 has three spheres 31. In the following description, the three spheres 31 may be distinguished and referred to as "first sphere 31A,""second sphere 31B," and "third sphere 31P," respectively.

The three spheres 31 are arranged so as not to be arranged in a straight line. That is, the center of one sphere 31 (for example, the third sphere 31P) is located at a different position from the line connecting the centers of two other spheres 31 (for example, the first sphere 31A and the second sphere 31B). As a result, by finding the center positions of the three spheres 31, the angle of the lidar device 10 (θx, θy, θz; θx is the angle around the x-axis, θy is the angle around the y-axis, and θz is the angle around the z-axis). angle), and it becomes possible to adjust the angle of the lidar device 10 (described later).

The support member 32 has a base portion 33, a support column 34, and a beam member 35. The beam member 35 is a member that supports the two spheres 31 at a predetermined height. In other words, the beam member 35 is a member that supports the two spheres 31 horizontally. Here, the beam member 35 supports the first sphere 31A and the second sphere 31B, respectively. The two spheres 31 are supported at a predetermined height by having the center of the beam member 35 supported by the pillar 34. Note that the third sphere 31P is arranged at a different height from the first sphere 31A and the second sphere 31B held by the beam member 35. As a result, the center of the third sphere 31P is located at a different position from the line connecting the centers of the first sphere 31A and the second sphere 31B.

A compass needle 36 is provided on the beam member 35 . The compass needle 36 is arranged at the center of the beam member 35. By providing the magnetic compass 36 on the beam member 35, it becomes easy to arrange the first sphere 31A and the second sphere 31B along a desired direction. For example, referring to the magnetic compass 36, the operator places the target device 30 so that the beam member 35 is along the east-west direction, and sets two spheres so that the first sphere 31A is on the west side and the second sphere 31B is on the east side. The target device 30 can be arranged so that the spheres 31 are aligned in the east-west direction.

The target device 30 of the second embodiment has a hanging member 37. The hanging member 37 is a member that suspends the sphere 31 (here, the third sphere 31P) from the support member 32. The hanging member 37 is composed of a thread-like or string-like member. The third sphere 31P is suspended by the hanging member 37, so that it can make a pendulum movement. Note that the third sphere 31P may be fixed to the support member 32 so as not to move. Even if the third sphere 31P is fixed in this way, the angle of the rider device 10 can be adjusted by determining the center positions of the three spheres 31 (described later). However, the movement of the third sphere 31P makes it possible to adjust the times of the two lidar devices 10 (described later).

In the second embodiment as well, it is desirable that the support member 32 (base portion 33, pillar 34, and beam member 35) have a lower reflectance of measurement light than the sphere 31. This makes it easier to extract the point cloud data of the sphere 31 from the point cloud data of the entire measurement area. Also in the second embodiment, it is desirable that the support member 32 (base portion 33, support column 34, and beam member 35) is foldable, and the sphere 31 is an inflatable structure such as an air bag. It is desirable that there be. Thereby, the target device 30 has a structure that is easy to transport, and the installation and removal of the target device 30 becomes easy.

<Adjustment method: 6-axis adjustment>
FIG. 9 is a flow diagram of the adjustment method according to the second embodiment. The processing in S202 to S205 in the figure is realized by the arithmetic unit forming the control device 20 executing the adjustment program.

Also in the second embodiment, the operator first installs the target device 30 at a predetermined position (S201). Note that since the target device 30 is used to adjust the time of the two lidar devices 10 (described later), the target device 30 is preferably installed within a common measurement area of the two lidar devices 10. .

FIGS. 10A and 10B are explanatory diagrams of the installation situation of the target device 30 of the second embodiment.

FIG. 10A shows a coordinate system on the map. In the following description, the coordinate system on the map may be referred to as the "first coordinate system." In the first coordinate system, the x-axis runs along the east-west direction, with the east side being the plus x direction and the west side being the minus x direction. Further, the y-axis runs along the north-south direction, with the north side being the plus y direction and the south side being the minus y direction. Further, the z-axis direction is along the vertical direction, and the upper side is the plus z direction. As shown in FIGS. 10A and 10B, it is assumed that the target device 30 is installed at coordinates (X _t , Y _t , Z _t ) with respect to the origin (0, 0, 0) on the map. Further, it is assumed that the target device 30 is installed so that the beam member 35 is along the x-axis direction (east-west direction). In this embodiment, since the compass needle 36 is provided on the beam member 35, it becomes easy to install the target device 30 so that the beam member 35 is aligned in the east-west direction.

As shown in FIG. 10B, the first spherical body 31A and the second spherical body 31B are supported by the beam member 35 at a predetermined interval. Here, the distance between the center of the first sphere 31A and the center of the second sphere 31B is 2L. Further, the first spherical body 31A and the second spherical body 31B are supported at a predetermined height by the pillars 34 (and the beam members 35). Here, the height of the center A of the first sphere 31A and the center B of the second sphere 31B is assumed to be H. Furthermore, the intermediate position between the center A of the first sphere 31A and the center B of the second sphere 31B is M, and the position of the upper end of the hanging member 37 is also M. Further, the center of the third sphere 31P is P, and the length from the intermediate position M to the center P of the third sphere 31P (the length of the hanging member 37) is l. Note that at this point, the target device 30 is installed with the third sphere 31P stationary.

In the first coordinate system, the coordinates of the center A of the first sphere 31A are (X _t -L, Y _t , Z _t +H), and the coordinates of the center B of the second sphere 31B are (X _t +L, Y _t , Z _t +H), and the coordinates of the center P of the third sphere 31P are (X _t , Y _t , Z _t +H−l). Further, when the center of the first sphere 31A is A and the center of the second sphere 31B is B, the vector AB in the first coordinate system is [2L 0 0] ^T . Further, when the third sphere 31P is stationary, the vector MP in the first coordinate system is [0 0 H−l] ^T . When the operator inputs the position (coordinates) where the target device 30 is installed into the control device 20, the control device 20 receives information about the positions (coordinates) of the three spheres, vector AB, and vector MP in the first coordinate system. can be obtained.

Next, the adjustment unit 22 of the control device 20 causes the lidar device 10 to measure the measurement area (S202). The point cloud data of the measurement area includes point cloud data of three spheres 31 (point cloud data of a hemisphere). The point data forming the point group data indicates coordinates along the coordinate axis of the lidar device 10. In the following description, the coordinate system on the point cloud data (the coordinate system on the lidar device 10) may be referred to as a "second coordinate system."

Next, the adjustment unit 22 extracts point cloud data of the three spheres 31 from the point cloud data of the measurement area (S203), and based on the point cloud data of each sphere 31, the center coordinates of the sphere 31 ( (reference position) are calculated (S204). Note that the processing in S203 and S204 is almost the same as the processing in S103 and S104 described above, so the description thereof will be omitted here. In S204, the center coordinates of the sphere 31 on the second coordinate system are calculated.

Next, the adjustment unit 22 performs processing for adjusting the six axes (x, y, z, θx, θy, and θz) of the lidar device 10 based on the center coordinates of the three spheres 31 (S205). .
For example, the adjustment unit 22 calculates vector AB and vector MP in the second coordinate system based on the center coordinates of the three spheres 31 calculated in S204. Then, the adjustment unit 22 adjusts the lidar device for the x-axis, y-axis, and z-axis of the first coordinate system based on the vector AB and vector MP in the first coordinate system and the vector AB and vector MP in the second coordinate system. 10 angles (angle θx around the x-axis, angle θy around the y-axis, and angle θz around the z-axis) can be determined, and a rotational coordinate transformation matrix can be determined. The rotational coordinate transformation matrix corresponds to an angle adjustment value (adjustment data related to adjustment of the lidar device) for adjusting the angle of the second coordinate system (the angle of the lidar device 10) with respect to the first coordinate system. Further, the adjustment unit 22 converts the center coordinates of the sphere 31 in the second coordinate system based on the rotational coordinate conversion matrix, and converts the center coordinates of the sphere 31 in the first coordinate system based on the difference between the converted coordinates and the center coordinates of the sphere 31 in the first coordinate system. , calculate offset values for the x-axis, y-axis, and z-axis. The offset value corresponds to a shift amount adjustment value (adjustment data related to adjustment of the lidar device) for adjusting the shift amount of the origin of the second coordinate system with respect to the origin of the first coordinate system. The adjustment section 22 stores the angle adjustment value and the shift amount adjustment value in a storage section (not shown). Note that after the adjustment process (after the target device 30 is removed from the measurement area), the measurement unit 21 of the control device 20 converts the coordinates of the point cloud data acquired from the lidar device 10 into adjustment values (angle adjustment value and shift amount adjustment). By correcting the point cloud data represented by the second coordinate system (value), the point cloud data represented by the second coordinate system can be adjusted to the point cloud data represented by the first coordinate system.

<Adjustment method: Time adjustment>
FIG. 11 is a flow diagram of time adjustment. The processes of S302 to S304 in the figure are realized by the arithmetic unit forming the control device 20 executing the adjustment program.

Before the time adjustment process shown in the figure is performed, the adjustment process shown in FIG. 10 is performed on each of the two lidar devices 10 in advance. Therefore, at the stage of time adjustment, the adjustment unit 22 can convert the coordinates measured by each lidar device 10 into coordinates of the common first coordinate system. Further, when performing time adjustment, the target device 30 is installed within the common measurement area of the two lidar devices 10.

First, the operator causes the third sphere 31P of the target device 30 to make a pendulum movement (S301). Next, the adjustment unit 22 of the control device 20 simultaneously measures the third spherical body 31P in motion using the two lidar devices 10 (S302). The adjustment unit 22 causes each lidar device 10 to measure the measurement area to obtain point cloud data of the measurement area, extracts point cloud data of the third sphere 31P from the point cloud data of the measurement area, and extracts point cloud data of the third sphere 31P from the point cloud data of the measurement area. By repeating calculating the center coordinates of the third sphere 31P based on the point group data of the three spheres 31P, the center coordinates of the third sphere 31P are calculated at each time (S303). Note that since the adjustment process shown in FIG. 10 has already been performed in advance, the adjustment unit 22 calculates the center coordinates of the third sphere 31P in the first coordinate system at each time.

FIG. 12 is an explanatory diagram of the time adjustment value Δt. In the figure, a time change P1(t) of the center coordinates of the third sphere 31P measured by one lidar device 10 and a time change P2 of the center coordinates of the third sphere 31P measured by the other lidar device 10 are shown. (t) is shown. The horizontal axis in the figure is time t. The vertical axis in the figure is, for example, the x coordinate (first coordinate system) of the third sphere 31P, but other coordinates may be used.

If the built-in clocks of the two lidar devices 10 are out of sync, as shown in the figure, even if the two lidar devices 10 measure the third sphere 31P at the same time in S302, each lidar device 10 will not be able to measure the third sphere 31P. The temporal change in the center coordinates of the third sphere 31P may deviate. Therefore, the adjustment unit 22 adjusts the times of the two lidar devices 10 based on the center coordinates of the third sphere 31P for each time (S304). For example, the adjustment unit 22 is configured to minimize the difference between the center coordinates of the third sphere 31P measured by one lidar device 10 and the center coordinates of the third sphere 31P measured by the other lidar device 10. Calculate the offset value (time adjustment value). In other words, the adjustment unit 22 calculates the time adjustment value Δt that minimizes P1(t)−P2(t+Δt).

Note that after the adjustment process (after the target device 30 is removed from the measurement area), the measurement unit 21 of the control device 20 uses the time information (time stamp) of the point cloud data acquired from the lidar device 10 according to the time adjustment value Δt. By correcting, the time information of the point cloud data of the plurality of lidar devices 10 can be adjusted, and time synchronization can be performed between the plurality of lidar devices 10.

In the present embodiment, the adjustment unit 22 of the control device 20 adjusts the output result of the lidar device 10 (corrects the coordinates of point group data) as adjustment of the lidar device 10. However, the adjustment of the lidar device 10 is not limited to this. For example, the adjustment unit 22 of the control device 20 may display adjustment values (corresponding to adjustment data regarding adjustment of the lidar device) on a display in order to adjust the arrangement of the lidar device 10. Thereby, the operator can adjust the position and angle of the lidar device 10 according to the adjustment values displayed on the display.

===Summary===
The target device 30 of the first embodiment and the second embodiment includes a sphere 31 that reflects the measurement light emitted by the lidar device 10. This allows the lidar device 10 to measure point cloud data for a hemisphere of the sphere 31 from any position and from any angle, so restrictions on the placement of the target device 30 can be alleviated.

Further, the target device 30 of the second embodiment includes three spheres 31, and the center of one of the three spheres 31 (for example, the third sphere 31P) is located at the center of another two spheres 31 (for example, the third sphere 31P). It is arranged at a different position from the line connecting the centers of the first sphere 31A and the second sphere 31B. This makes it possible to adjust the angle of the rider device 10.

Furthermore, in the target device 30 of the second embodiment, the two spheres 31 (the first sphere 31A and the second sphere 31B) are supported at a predetermined height by the beam member 35, and one sphere 31 (the third sphere 31P) is arranged at a different height from the two spheres 31 supported by the beam member 35. Thereby, the three spheres 31 can be arranged so that the three spheres 31 are not located in a straight line.

Further, the target device 30 of the second embodiment includes a compass needle 36 that indicates the direction of the beam member 35. This makes it easy to install the target device 30 so that the two spheres 31 are aligned in a predetermined direction.

Further, the target device 30 of the second embodiment includes a support member 32 and a hanging member 37 that suspends the sphere 31 from the support member 32, and can cause the sphere 31 to make a pendulum movement. This makes it possible to adjust the time of the lidar device 10.

In addition, in the first embodiment and the second embodiment, it is desirable that the support member 32 has a lower reflectance of measurement light than the sphere 31. This makes it easier to extract the point group data of the sphere 31. Further, in the first embodiment and the second embodiment, it is desirable that the support member 32 is foldable. This provides a structure in which the target device 30 is easily transported. Further, in the first embodiment and the second embodiment, the sphere 31 is preferably an inflatable structure. This provides a structure in which the target device 30 is easily transported.

In the adjustment methods of the first and second embodiments, the target device 30 including the sphere 31 is installed in the measurement area (measurement range) of the lidar device 10 (S101, S201), and the lidar device 10 is used to measure the sphere 31. measuring the coordinates of multiple points on the surface of the sphere 31 (S102 and S103, S202 and S203), measuring the position of the sphere 31 based on the coordinates of the multiple points on the surface of the sphere 31 (S104, S204), and The rider device 10 is adjusted based on the position of the rider 31 (S105, S205). According to such an adjustment method, restrictions on the arrangement of the target device 30 can be alleviated, so that the adjustment work of the lidar device 10 becomes easier.

In addition, in the adjustment methods of the first embodiment and the second embodiment, based on the coordinates (x _i , y _i , z _i ) indicated by the plurality of point data constituting the point cloud data, the coordinates ( The center coordinates (x _c , y _c , z _c ) of the spherical surface are calculated by finding a maximum likelihood estimate such that x _i , y _i , z _i ) plausibly fits the equation of the spherical surface. This allows the lidar device 10 to measure the reference position (the center of the sphere 31) of the target device 30 from any position and from any angle.

Furthermore, in the adjustment methods of the first and second embodiments, the position of the lidar device 10 is adjusted based on the installation position of the target device 30 and the center position of the sphere 31 measured by the lidar device 10. Thereby, the deviation between the reference coordinate system and the coordinate system of the lidar device 10 can be adjusted. Furthermore, in the adjustment method of the second embodiment, the angle of the lidar device 10 is adjusted based on the center positions of the three spheres 31 measured by the lidar device 10. Thereby, the angular deviation between the reference coordinate system and the coordinate system of the lidar device 10 can be adjusted. Further, in the second embodiment, the sphere 31 is caused to move, and the two lidar devices 10 measure the position of the sphere 31 at each time, and the position of the sphere 31 at each time measured by the two lidar devices 10 is measured. The times of the two lidar devices 10 are adjusted based on the positions. Thereby, the time difference between the two lidar devices 10 can be adjusted.

The adjustment system 1 of the first embodiment and the second embodiment includes a lidar device 10, a control device 20 (corresponding to a computer), and a target device 30. Then, the control device 20 (equivalent to a computer) obtains the coordinates of multiple points on the surface of the sphere 31 from the lidar device 10 with the sphere 31 of the target device 30 placed in the measurement area (measurement range) of the lidar device 10. measuring the position of the sphere 31 based on the coordinates of a plurality of points on the surface of the sphere 31 (S104, S204); and measuring the position of the sphere 31 based on the position of the sphere 31 (S105, S205). According to such an adjustment system 1, restrictions on the arrangement of the target device 30 can be alleviated, so that the adjustment work of the lidar device 10 becomes easier.

Further, the adjustment programs of the first embodiment and the second embodiment are configured such that the control device 20 (corresponding to a computer) is configured to control the control device 20 (corresponding to a computer) when the sphere 31 of the target device 30 is placed in the measurement area (measurement range) of the lidar device 10. 31 from the lidar device 10 (S102 and S103, S202 and S203), and measuring the position of the sphere 31 based on the coordinates of the plurality of points on the surface of the sphere 31 (S104, S204). ), and generating adjustment data regarding the adjustment of the lidar device 10 based on the position of the sphere 31 (S105, S205). According to such an adjustment program, restrictions on the arrangement of the target device 30 can be alleviated, so that the adjustment work of the lidar device 10 becomes easier.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and includes various modifications. In addition, the above-described embodiments have been described in detail to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all the described configurations. Further, some of the configurations of the above embodiments can be added to, deleted from, or replaced with other configurations.

1 adjustment system, 10 lidar device,
20 control device, 21 measurement section, 22 adjustment section,
30 target device, 31 sphere,
31A first sphere, 31B second sphere, 31P third sphere,
32 supporting member, 33 base, 34 pillar,
35 beam member, 36 compass needle,
37 Hanging members

Claims (8)

A target device used for adjusting a lidar device, the target device comprising:
comprising a sphere that reflects the measurement light emitted by the lidar device;
Target device. The target device according to claim 1,
It is equipped with three of the spheres,
The center of one of the three spheres is located at a different position from a line connecting the centers of two other spheres,
Target device. The target device according to claim 2,
Two of the three spheres are supported at a predetermined height by a beam member,
One of the three spheres is arranged at a different height from the two spheres supported by the beam member,
Target device. 4. The target device according to claim 3,
comprising a compass needle that indicates the direction of the beam member;
Target device. The target device according to any one of claims 1 to 4,
a support member;
a hanging member that suspends the sphere from the support member;
Equipped with
the sphere makes a pendulum movement;
Target device. installing a targeting device comprising a sphere;
Measuring the coordinates of a plurality of points on the surface of the spherical body by emitting measurement light from a lidar device toward the spherical body and receiving reflected light from the spherical body with the lidar device;
Measuring the position of the sphere based on the coordinates of a plurality of points on the surface of the sphere; and
An adjustment method that adjusts the lidar device based on the position of the sphere. a lidar device that outputs coordinate data indicating the coordinates of a reflection point of the reflected light by emitting measurement light and receiving the reflected light;
a computer that processes the coordinate data of the lidar device;
a target device having a sphere that reflects the measurement light;
Equipped with
The computer includes:
acquiring the coordinate data of a plurality of points on the surface of the sphere from the lidar device with the sphere placed in the measurement range of the lidar device;
Measuring the position of the sphere based on the coordinate data of a plurality of points on the surface of the sphere,
generating adjustment data regarding adjustment of the lidar device based on the position of the sphere;
adjustment system. to the computer,
acquiring coordinate data of a plurality of points on the surface of the sphere from the lidar device with the sphere placed in a measurement range of the lidar device;
Measuring the position of the spherical body based on the coordinate data of a plurality of points on the surface of the spherical body; and Generating adjustment data regarding adjustment of the lidar device based on the position of the spherical body.
Adjustment program to run.

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