A coupling method applied to a coupling system of multiple laser radars

Abstract

The application discloses a coupling method applied to a coupling system of multiple laser radars, and comprises the following steps: internal parameter calibration; multiple radar spatial distribution, so that the laser radars keep a basic geometric distribution position, wherein geometric parameters among the laser radars include offset d in X, Y and Z axis directions x , d y , d z , and rotation angles γ, β and α around the X, Y and Z axes; external parameter calibration; data collection and fusion, so that point cloud data of the laser radars are transformed to the same coordinate system. The coupling method couples multiple low-line-number laser radars, a coupling platform makes the laser radars meet geometric parameters, and outgoing light rays of the laser radars are uniformly inserted into outgoing light rays of the reference laser radars, so that point cloud data is increased and point cloud data fusion is performed.

Description

[0001] This application is a divisional application of Chinese application No. 201710510980.3, the foregoing is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of laser detection technology, and particularly relates to a coupling method applied to a coupling system of multiple laser radars. BACKGROUND

[0003] Laser radar is a radar system that detects the position, speed and other characteristic quantities of a target by emitting a laser beam. Its working principle is to emit a detection laser beam to a target first, then compare the received signal reflected from the target with the emitted signal, and after appropriate processing, the relevant information of the target, such as target distance, direction, height, speed, attitude, and even shape, can be obtained.

[0004] Due to the inherent advantages of laser radar in environmental perception, it has become the main sensor for automatic driving technology to detect the environment. Currently, the commercially available laser radars mainly have 16 lines, 32 lines, and 64 lines, among which the larger the number of lines, the more abundant the point cloud data obtained. In addition, laser radars are optical, mechanical and electrical integrated products, which require high precision and are difficult to manufacture, and the larger the number of lines, the higher the price. Low-line laser radars have relatively low cost, but the point cloud data obtained is also less. SUMMARY

[0005] The embodiment of the present application provides a coupling platform and system of multiple laser radars, which can obtain abundant point cloud data and reduce cost.

[0006] In order to solve the above technical problems, the embodiment of the present application discloses the following technical scheme:

[0007] In a first aspect, a coupling platform of multiple laser radars is provided, which comprises at least two bases for installing laser radars, the top surface of the base is a mounting surface, and the mounting surfaces are inclined in the same direction and have different inclination angles.

[0008] Preferably, the coupling platform comprises N (N≥2) bases, the included angle between the adjacent outgoing light rays of the laser radars is θ, one of the mounting surfaces is selected as a reference surface, the inclination angle of the reference surface is α, and the inclination angles of the other mounting surfaces are (α+θ / N), (α+2θ / N), …, (α+(N-1)θ / N).

[0009] Preferably, the laser radar includes N (N=2n, n≥1) bases, the included angle between adjacent outgoing light rays of the laser radar is θ, an installation surface is selected as a reference surface, the inclination angle of the reference surface is α, and the inclination angles of the remaining installation surfaces are (α+θ / N), (α+2θ / N),..., (α+(N-1)θ / N).

[0010] Preferably, each base group includes two adjacent bases.

[0011] Preferably, the difference between the inclination angles of the two installation surfaces of the base group is θ / 2.

[0012] Preferably, the centers of the installation surfaces are at the same height.

[0013] Preferably, the bases are located on the same straight line, and the distance between any two adjacent bases is equal.

[0014] Preferably, the installation surfaces are inclined by rotating around the X axis, and the X axis passes through the center of the installation surface and is perpendicular to the main direction of the outgoing light rays of the laser radar.

[0015] Preferably, a light barrier is further arranged between the adjacent bases.

[0016] In the second aspect, a coupling system of multiple laser radars is provided, which includes a coupling platform of multiple laser radars, two coupling platforms are arranged oppositely, and a laser radar is arranged between the coupling platforms, and the two ends of the laser radar are fixed by the bases of the coupling platforms.

[0017] The coupling platform of the multiple laser radars includes at least two bases for installing laser radars, the top surface of the base is an installation surface, the installation surfaces are inclined in the same direction and the inclination angles of the installation surfaces are different, two coupling platforms are arranged oppositely in use, a laser radar is arranged between the coupling platforms, and the two ends of the laser radar are fixed by the bases of the coupling platforms. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 Fig. 1 shows a structural schematic diagram of a coupling platform of a multi-laser radar according to an embodiment of the present application;

[0020] Figure 2 Fig. 2 shows a front view of the multi-laser radar according to the embodiment of the present application; Figure 1

[0021] Figure 3a Fig. 3 shows a sectional view of the multi-laser radar according to the embodiment of the present application in A-A direction; Figure 2

[0022] Figure 3b Fig. 4 shows a sectional view of the multi-laser radar according to the embodiment of the present application in B-B direction; Figure 2

[0023] Figure 3c Fig. 5 shows a sectional view of the multi-laser radar according to the embodiment of the present application in C-C direction; Figure 2

[0024] Figure 3d Fig. 6 shows a sectional view of the multi-laser radar according to the embodiment of the present application in D-D direction; Figure 2

[0025] Figure 4a Fig. 7 shows a schematic diagram of light distribution before coupling of outgoing light of the multi-laser radar according to the embodiment of the present application;

[0026] Figure 4b Fig. 8 shows a schematic diagram of fiber distribution after coupling of outgoing light of the multi-laser radar according to the embodiment of the present application;

[0027] Figure 5 Fig. 9 shows a schematic diagram of coupling effect of the multi-laser radar according to the embodiment of the present application;

[0028] Figure 6 Fig. 10 shows a structural schematic diagram of a coupling platform of a multi-laser radar according to another embodiment of the present application;

[0029] Figure 7 Fig. 11 shows a structural schematic diagram of a coupling system of a multi-laser radar according to another embodiment of the present application;

[0030] Figure 8 Fig. 12 shows a coupling flowchart of a multi-laser radar according to another embodiment of the present application.

[0031] Reference signs

[0032] ​​​​​100. Coupling platform; 110. Base; 111. First mounting surface; 112. Second mounting surface; 113. Third mounting surface; 114. Fourth mounting surface; 120. Boss; 130. Fixing hole; 140. Fixing base plate; 150. Light blocking plate; 200. Coupling platform; 210. Base; 211. First mounting surface; 212. Second mounting surface; 213. Third mounting surface; 300. Coupling platform; 310. LiDAR. Detailed Implementation

[0033] The present invention provides a coupling platform and coupling system for multiple lidars in the following embodiments, enabling the lidars to meet the geometric parameters during coupling and achieve the same effect as high-line-count lidars.

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1:

[0036] like Figure 1 As shown, the coupling platform 100 includes four bases 110 for mounting lidar. The distance between any two adjacent bases 110 is equal. The distance between the bases 110 is determined by the width of the mounting location and the desired effective field of view of the lidar. The top surface of the base 110 is the mounting surface, which is divided into a first mounting surface 111, a second mounting surface 112, a third mounting surface 113, and a fourth mounting surface 114 from left to right. The center of each mounting surface is at the same height. The mounting surface is rotated around the X-axis with the line connecting the centers of the mounting surfaces as the X-axis to achieve tilting. The mounting surfaces are tilted in the same direction, but the tilt angle of each mounting surface is different.

[0037] A ring-shaped boss 120 is provided along the circumference of the mounting surface, and a fixing hole 130 is provided on the mounting surface; during installation, the lidar is snapped into the boss 120 and fixed through the fixing hole 130. It also includes a fixing base plate 140, and the base 110 is set on the fixing base plate 140; the fixing base plate 140 facilitates the overall installation of the coupling platform 100 when it is used.

[0038] like Figure 2 , Figures 3a-3d As shown, it includes 4 bases 110. The angle between adjacent emitted light rays of the lidar is θ. One mounting surface is arbitrarily selected as the reference surface. The tilt angle of the reference surface is α. The tilt angles of the other 3 mounting surfaces are (α+θ / 4), (α+θ / 2), and (α+3θ / 4).

[0039] Each base group includes two adjacent bases 110; the difference between the inclination angles of the two mounting surfaces of the base group is θ / 2; the base group formed by two bases 110 is the minimum unit, and each minimum unit of the base group can meet the geometric parameters of the coupled outgoing laser beams during use, and several minimum units of the base group can also meet the geometric parameters of the coupled outgoing laser beams after being combined, thereby facilitating replacement and adjustment during use.

[0040] For example, the included angle between the adjacent outgoing light rays of the laser radar is 2°, the third mounting surface 113 is selected as the reference surface, the inclination angle of the reference surface is 11°, and the inclination angles of the other three mounting surfaces are 11.5°, 12°, and 12.5°, respectively, which are 11.5°, 12.5°, and 12° for the inclination angles of the first mounting surface 111, the second mounting surface 112, and the fourth mounting surface 114, respectively; the first mounting surface 111 and the second mounting surface 112 belong to one base group, and the difference between the inclination angles of the two is 1°; the third mounting surface 113 and the fourth mounting surface 114 belong to another base group, and the difference between the inclination angles of the two is also 1°.

[0041] As shown in Figure 4a and Figure 4b , the two adjacent outgoing light rays of the reference laser radar are shown in Figure 4a ; the reference laser radar is mounted on the reference surface; the remaining laser radars are mounted on the remaining mounting surfaces, and the outgoing light rays of the remaining laser radars are uniformly inserted into the outgoing light rays of the reference laser radar through the set geometric orientation distribution; as shown in Figure 4b , the outgoing light rays of the remaining three laser radars are uniformly inserted between the two adjacent outgoing light rays of the reference laser radar. The remaining outgoing light rays are also distributed in this way.

[0042] As shown in Figure 5 , light barriers 150 are also arranged between the adjacent bases 110; the light barriers 150 prevent mutual interference between the laser radars. The scanning ranges of the outgoing light rays of the four laser radars are shown in Figure 5 ; the outgoing light rays of the laser radars are m beams, and after the coupling of the multiple laser radars: the effective scanning outgoing light rays of the M1 region in the figure are m beams, the effective scanning outgoing light rays of the M2 region are 2m beams, the effective scanning outgoing light rays of the M3 region are 3m beams, and the effective scanning outgoing light rays of the M4 region are 4m beams. For example, the outgoing light rays of the laser radars are 16 beams, and after the coupling of the multiple laser radars: the effective scanning outgoing light rays of the M1 region in the figure are 16 beams, the effective scanning outgoing light rays of the M2 region are 32 beams, the effective scanning outgoing light rays of the M3 region are 48 beams, and the effective scanning outgoing light rays of the M4 region are 64 beams; the scanning effect of the M4 region is the same as that of the 64-line laser radar with a high line beam.

[0043] Example 2:

[0044] like Figure 6 As shown, the coupling platform 200 includes three bases 210 for mounting lidar, with equal distance between any two adjacent bases 210; the top surface of the base 210 is the mounting surface, which is the first mounting surface 211, the second mounting surface 212, and the third mounting surface 213 from left to right; the center of each mounting surface is at the same height; the mounting surface is tilted by rotating around the X-axis with the line connecting the centers of the mounting surfaces as the X-axis; the mounting surfaces are tilted in the same direction and the tilt angle of each mounting surface is different.

[0045] The angle between adjacent emitted light rays of the lidar is θ. One mounting surface is arbitrarily selected as the reference surface, and the tilt angle of the reference surface is α. The tilt angles of the other two mounting surfaces are (α+θ / 3) and (α+2θ / 3).

[0046] For example, the angle between adjacent emitted light rays of the lidar is 3°, the second mounting surface is selected as the reference surface, the tilt angle of the reference surface is 11°, and the tilt angles of the other three mounting surfaces are 12° and 13°, respectively the tilt angle of the first mounting surface 211 is 12° and the tilt angle of the third mounting surface 213 is 13°.

[0047] Embodiments 1 and 2 of the present invention disclose a coupling platform for multiple lidars, which is used to install and couple multiple lidars, so that the lidars meet the geometric parameters during coupling, and the emitted light of the lidar is uniformly inserted into the emitted light of the reference lidar, thereby increasing the point cloud data and achieving the same scanning effect as high line count lidars; reducing costs and meeting various application scenarios.

[0048] Example 3:

[0049] like Figure 7 As shown, the coupling platform 300 includes the above-mentioned multi-laser radar, with two coupling platforms 300 arranged opposite each other, and also includes a laser radar 310 disposed between the coupling platforms 300, with both ends of the laser radar 310 fixed by the base of the coupling platform 300.

[0050] like Figure 8 As shown, the multi-lidar coupling process includes the following steps:

[0051] Step S301: Internal parameter calibration; ensure the spatial coordinates of the point cloud data acquired by the lidar are accurate, mainly by correcting the lidar's ranging D, pitch angle ψ, and horizontal rotation angle θ.

[0052] Step S302: Spatial distribution of multiple lidars; maintain a basic geometric distribution position for the lidars, with the following geometric parameters between the lidars: offset d in the X, Y, and Z axis directions.x , d y , d z , and rotation angles γ, β, α around X, Y, Z axes.

[0053] Step S303: external parameter calibration; determine the rotation matrix R x , d y , d z , γ, β, α) between multiple laser radars through the geometric parameters of the spatial distribution of the radar 3x3 and the translation matrix T 3x1 , and the calculation formula is as follows:

[0054]

[0055]

[0056] Step S304: data acquisition and fusion; transform the point cloud data of multiple laser radars into the same coordinate system. For example, two laser radars are coupled: the coordinate system of the first radar is W, and the coordinates of the point cloud data obtained by the first radar can be represented as (x w , y w , z w ); the coordinate system of the second radar is U, and the coordinates of the point cloud data obtained by the second radar can be represented as (x u , y u , z u ); take the coordinate system W of the first radar as the reference, transform the point cloud data of the second radar into the coordinate system W of the first radar through the rotation matrix R 3x3 and the translation transformation matrix T 3x1 , realize data fusion of the first radar and the second radar, and the calculation formula is as follows:

[0057]

[0058] Embodiment three of the application discloses a coupling system of multiple laser radars, which is used for coupling multiple laser radars, fixing the laser radars between the coupling platforms, making the laser radars meet the geometric parameters during coupling, uniformly inserting the outgoing light rays of the laser radars into the outgoing light rays of the reference laser radars, and increasing the point cloud data; data fusion is performed on the point cloud data collected by each laser radar, a high-line laser radar is replaced, and the cost is reduced.

[0059] Each embodiment in the specification is described in a progressive manner, and the same or similar parts of each embodiment can be referred to each other. Each embodiment mainly describes the differences from other embodiments. Especially, since the system embodiment is basically similar to the method embodiment, the description is relatively simple, and the related parts can be referred to the part of the method embodiment.

[0060] The above-mentioned embodiments of the present application are not intended to limit the scope of the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall fall within the scope of the present application.

Claims

1. A coupling method for a coupling system of multiple lidar systems, wherein, The coupling system includes a coupling platform and a lidar. The coupling platform includes N bases for mounting the lidar, where N is greater than or equal to 2. The top surface of each base is a mounting surface. The angle between adjacent emitted rays from the lidar is θ. One mounting surface is arbitrarily selected as a reference surface, with an inclination angle of α. The inclination angles of the remaining mounting surfaces are (α+θ / N), (α+2θ / N), ..., (α+(N-1)θ / N). The two ends of the lidar are fixed by the bases of the coupling platform. The coupling method includes the following steps: Internal reference calibration; The spatial distribution of multiple lidars ensures that the lidars maintain a basic geometric distribution position, wherein the geometric parameters between the lidars include offsets d in the X, Y, and Z axis directions. x d y d z , and rotation angles γ, β, α about the X, Y, and Z axes; External parameter calibration; Data is collected and fused, and the point cloud data of the lidar is transformed to the same coordinate system.

2. The coupling method for a coupling system applied to multiple lidar systems as described in claim 1, characterized in that, The internal parameter calibration includes correcting the range D, elevation angle ψ, and horizontal rotation angle θ of the lidar.

3. The coupling method for a coupling system applied to multiple lidar systems as described in claim 1 or 2, characterized in that, The external parameter calibration includes: using the geometric parameters (d) of the radar spatial distribution. x d y d z Determine the rotation matrix R among multiple lidars using γ, β, and α. 3x3 With translation matrix T 3x1 .

4. The coupling method for a coupling system applied to multiple lidar systems as described in claim 3, characterized in that, The geometric parameters (d) distributed through radar space x d y d z Determine the rotation matrix R among multiple lidars using γ, β, and α. 3x3 With translation matrix T 3x1 The calculation formula is as follows:

5. The coupling method for a coupling system applied to multiple lidars as described in claim 1 or 2, wherein the number of lidars is 2, the two lidars being a first lidar and a second lidar respectively, the coordinate system of the first lidar is W, and the coordinates of the point cloud data acquired by the first lidar are represented as (x... w ,y w ,z w The second radar's coordinate system is U, and the coordinates of the point cloud data acquired by the second radar are represented as (x...). u ,y u ,z u ), characterized in that, The process of collecting and fusing data, and transforming the point cloud data of the lidar to the same coordinate system, includes: Using the coordinate system W of the first radar as a reference, and through the rotation matrix R... 3x3 Translation matrix T 3x1 The point cloud data of the second radar is transformed into the coordinate system W of the first radar to achieve data fusion between the first and second radars. The calculation formula is as follows:

Images