CN111427027A

CN111427027A - Method, device and system for calibrating multi-line laser radar

Info

Publication number: CN111427027A
Application number: CN202010158016.0A
Authority: CN
Inventors: 胡小波; 刘云备
Original assignee: LeiShen Intelligent System Co Ltd
Current assignee: LeiShen Intelligent System Co Ltd
Priority date: 2020-03-09
Filing date: 2020-03-09
Publication date: 2020-07-17

Abstract

The embodiment of the invention discloses a method, a device and a system for calibrating a multi-line laser radar. The method comprises the following steps: acquiring spot images formed by laser beams emitted by at least two laser emitters in a multi-line laser radar in a calibration environment, wherein the calibration environment comprises at least two reference points with preset distances; determining a first distance between adjacent light spots in the light spot image according to the light spot image and a preset distance; determining a second distance between a first light spot in adjacent light spots and the multi-line laser radar and a third distance between a second light spot in the adjacent light spots and the multi-line laser radar according to laser beams received by the multi-line laser radar; and determining the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar according to the first distance, the second distance and the third distance, and calibrating the actual vertical angle between the adjacent laser transmitters. According to the embodiment of the invention, the calibration speed and the calibration accuracy of the multi-line laser radar are improved.

Description

Method, device and system for calibrating multi-line laser radar

Technical Field

The embodiment of the invention relates to the technical field of laser radars, in particular to a method, a device and a system for calibrating a multi-line laser radar.

Background

The multiline laser radar is one kind of laser radar, and utilizes several laser transmitters to emit several laser beams to detect the position of obstacle, the direction of obstacle and the distance between obstacles. Usually, part of laser transmitters in the multi-line laser radar are installed according to a vertical arrangement mode (also called a linear array arrangement mode), and a certain vertical angle is formed between adjacent laser transmitters, so that detection in a certain range in the vertical direction is realized.

Due to the process problem, errors exist between the actual installation positions of a plurality of laser transmitters in the multi-line laser radar and the designed installation positions, so that the actual vertical angle and the theoretical vertical angle between the adjacent laser transmitters have deviation, and the detection range of the multi-line laser radar in the vertical direction is further influenced. Therefore, after the multiple laser transmitters in the multi-line beam lidar are installed, the vertical angle between adjacent laser transmitters needs to be calibrated. At present, the multi-line laser radar is placed on a rotating platform, a stepping motor electrically connected with the rotating platform is controlled to rotate by a certain angle, and the rotating angle of each laser transmitter in the multi-line laser radar is recorded. And then, calculating to obtain the actual vertical angle between the adjacent laser transmitters according to the recorded rotating angle of each laser transmitter, comparing the obtained actual vertical angle between the adjacent laser transmitters with the theoretical vertical angle, determining whether to adjust the vertical angle of the adjacent laser transmitters in the multi-line laser radar, and performing corresponding adjustment when the adjustment is needed.

However, when the above method calibrates the vertical angle of the adjacent laser emitters, it is to measure the angle of the single laser emitter first, and then obtain the actual vertical angle between the adjacent laser emitters according to the angle measurement result of the single laser emitter, so that the zero-angle position cannot be determined, and the calibration speed is slow.

Disclosure of Invention

The embodiment of the invention provides a method, a device and a system for calibrating a multi-line laser radar, which improve the calibration speed and accuracy of the multi-line laser radar.

In a first aspect, an embodiment of the present invention provides a method for calibrating a multiline laser radar, where the method includes:

acquiring spot images formed by laser beams emitted by at least two laser emitters in the multi-line laser radar in a calibration environment, wherein the calibration environment comprises at least two reference points with preset distances;

determining a first distance between adjacent light spots in the light spot image according to the light spot image and the preset distance;

according to the laser beams received by the multi-line laser radar, determining a second distance between a first light spot in the adjacent light spots and the multi-line laser radar and a third distance between a second light spot in the adjacent light spots and the multi-line laser radar;

and determining the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar according to the first distance, the second distance and the third distance, and calibrating the actual vertical angle between the adjacent laser transmitters.

In a second aspect, an embodiment of the present invention further provides a calibration method for a multiline laser radar, where the method includes:

according to the light spot image and the preset distance, determining a fourth distance between a first light spot in adjacent light spots in the light spot image and the center position of the light spot image and a fifth distance between a second light spot in the adjacent light spots and the center position of the light spot image, and acquiring a vertical distance between the multi-line laser radar and the curtain;

determining a sixth distance between the first spot and the multiline lidar based on the fourth distance and the vertical distance, and determining a seventh distance between the second spot and the multiline lidar based on the fifth distance and the vertical distance;

determining a first included angle between the sixth distance and the vertical distance according to the fourth distance, the vertical distance and the sixth distance, and determining a second included angle between the seventh distance and the vertical distance according to the fifth distance, the vertical distance and the seventh distance;

and determining the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar according to the first included angle and the second included angle, and calibrating the actual vertical angle between the adjacent laser transmitters.

In a third aspect, an embodiment of the present invention further provides a calibration apparatus for a multiline laser radar, where the apparatus includes:

the system comprises a light spot image acquisition module, a light spot image acquisition module and a calibration module, wherein the light spot image acquisition module is used for acquiring light spot images formed in a calibration environment by laser signals emitted by at least two laser transmitters in the multi-line laser radar, and the calibration environment comprises at least two reference points with preset distances;

the first distance determining module is used for determining a first distance between adjacent light spots in the light spot image according to the light spot image and the preset distance;

the first distance determining module is further configured to determine, according to the laser beam received by the multi-line lidar, a second distance between a first spot of the adjacent spots and the multi-line lidar, and a third distance between a second spot of the adjacent spots and the multi-line lidar;

and the first angle determining and calibrating module is used for determining the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar according to the first distance, the second distance and the third distance, and calibrating the actual vertical angle between the adjacent laser transmitters.

In a fourth aspect, an embodiment of the present invention further provides a calibration apparatus for a multiline laser radar, where the apparatus includes:

the system comprises a light spot image acquisition module, a light spot image acquisition module and a calibration module, wherein the light spot image acquisition module is used for acquiring light spot images formed in a calibration environment by laser beams emitted by at least two laser emitters in the multi-line laser radar, and the calibration environment comprises at least two reference points with preset distances;

the second distance determining module is used for determining a fourth distance between a first light spot in adjacent light spots in the light spot image and the central position of the light spot image and a fifth distance between a second light spot in the adjacent light spots and the central position of the light spot image according to the light spot image and the preset distance, and acquiring a vertical distance between the multi-line laser radar and the curtain;

the second distance determining module is further configured to determine a sixth distance between the first light spot and the multiline lidar according to the fourth distance and the vertical distance, and determine a seventh distance between the second light spot and the multiline lidar according to the fifth distance and the vertical distance;

an included angle determining module, configured to determine a first included angle between the first light spot and the light spot image center position according to the fourth distance, the vertical distance, and the sixth distance, and determine a second included angle between the second light spot and the light spot image center position according to the fifth distance, the vertical distance, and the seventh distance;

and the second angle determining and calibrating module is used for determining the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar according to the first included angle and the second included angle and calibrating the actual vertical angle between the adjacent laser transmitters.

In a fifth aspect, an embodiment of the present invention further provides a calibration system for a multiline laser radar, where the system includes:

the multi-line laser radar is used for emitting a plurality of laser beams and receiving the laser beams;

the camera is used for acquiring spot images formed by laser beams emitted by at least two laser emitters in the multi-line laser radar in a calibration environment;

the calibration device comprises a memory and a processor, wherein the memory stores a computer program, so that the processor realizes the calibration method of the multiline laser radar in the embodiment of the invention when executing the computer program.

The technical scheme disclosed by the embodiment of the invention has the following beneficial effects:

through gathering the laser beam of two at least laser emitter launches among the multi-line laser radar, the facula image that forms in the calibration environment, and according to the facula image with predetermine the distance, confirm the first distance between the adjacent facula in the facula image, according to the laser beam that multi-line laser radar received, confirm the second distance between first facula and the multi-line laser radar among the adjacent facula, and the third distance between second facula and the multi-line laser radar among the adjacent facula, then according to first distance, second distance and third distance, confirm the actual vertical angle between the adjacent laser emitter among the multi-line laser radar, and calibrate the actual vertical angle between the adjacent laser emitter. From this, realize carrying out short-term test to the actual vertical angle between the adjacent laser emitter among the multi-line laser radar, and solved because of the error that step motor exists, lead to the problem that vertical angle calibration precision is low between the adjacent laser emitter to the calibration speed and the precision to multi-line laser radar have been improved.

Drawings

Fig. 1 is a schematic flowchart of a calibration method for a multiline lidar according to an embodiment of the present invention;

fig. 2(a) is a schematic diagram of a spot image collected in the first embodiment of the present invention;

FIG. 2(b) is a schematic diagram of determining an actual vertical angle between adjacent laser emitters in a multi-line lidar based on a spot image and the multi-line lidar, in accordance with an embodiment of the present invention;

fig. 3 is a schematic flowchart of a calibration method for a multiline lidar according to a second embodiment of the present invention;

fig. 4 is a schematic flowchart of another calibration method for a multiline lidar according to a third embodiment of the present invention;

fig. 5 is a schematic diagram of determining a sixth distance between a first spot of adjacent spots and the multi-line lidar and a seventh distance between a second spot of adjacent spots and the multi-line lidar, according to the third embodiment of the invention;

fig. 6 is a schematic structural diagram of a calibration apparatus for a multiline lidar according to a fourth embodiment of the present invention;

fig. 7 is a schematic structural diagram of a calibration apparatus for a multiline lidar according to a fifth embodiment of the present invention;

fig. 8 is a schematic structural diagram of a calibration system of a multiline lidar according to a sixth embodiment of the present invention.

Detailed Description

The embodiments of the present invention will be described in further detail with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of and not restrictive on the broad invention. It should be further noted that, for convenience of description, only some structures, not all structures, relating to the embodiments of the present invention are shown in the drawings.

Example one

Fig. 1 is a schematic flowchart of a calibration method for a multiline lidar according to an embodiment of the present invention, where the method is applicable to a scenario in which a vertical angle between adjacent laser transmitters in the multiline lidar is calibrated, and the method may be implemented by a calibration apparatus for the multiline lidar, where the calibration apparatus may be composed of hardware and/or software and may be integrated in a calibration system for the multiline lidar. The method specifically comprises the following steps:

s101, acquiring spot images formed by laser beams emitted by at least two laser emitters in the multi-line laser radar in a calibration environment, wherein the calibration environment comprises at least two reference points with preset distances.

Before S101 is executed, the embodiment of the present invention may first set up a calibration environment of the multiline lidar and place the multiline lidar in the calibration environment.

During specific implementation, a curtain can be arranged on the blank wall, at least two reference points with preset distances are arranged in the curtain, and the distance proportionality coefficient is determined according to the preset distances between the at least two reference points and the number of pixel points between the at least two reference points in the image shot by the camera. In this embodiment, at least two reference points with preset distances in the curtain may be set according to the same horizontal line, or may also be set according to the same vertical line, which is not limited herein. For clarity of the description of the embodiments of the present invention, the following description will be made by taking at least two reference points in the curtain as an example, which are set according to the same horizontal line. Wherein the preset distance is determined based on an actual distance between at least two reference points.

In this embodiment, determining the distance scaling factor specifically includes: if the number of the reference points is two, measuring the distance between the two reference points by using a distance meter, and dividing the distance between the two reference points by the number of pixel points between the two reference points in the image with the two reference points to obtain a distance proportion coefficient; if the number of the reference points is more than two, the distance between two adjacent reference points and the number of pixel points between the two reference points in the image with the two reference points are measured by using a distance meter respectively, after distance scale coefficients are obtained, all the distance scale coefficients are added and averaged, and the calculated average value is used as a final distance scale coefficient.

It should be noted that, in order to ensure that laser beams sent by at least two laser transmitters in the multiline lidar form clear spots on the curtain, the embodiment of the present invention may select a curtain with a color with less reflection, such as gray, to reduce reflection interference.

After the curtain is set, the width of the curtain can be determined by using a range finder or based on curtain size information, and then the multi-line laser radar is fixed at a preset pose, so that a light spot formed by a multi-line laser beam emitted by the multi-line laser radar in the calibration environment is parallel to a straight line formed by at least two reference points. For example, if the at least two reference points are arranged in the same horizontal direction in the curtain, the posture of the multiline laser beam emitted by the multiline lidar and the parallel posture of the at least two reference points in the same horizontal direction in the curtain are controlled to be fixed, and the multiline lidar is controlled to be in a static mode, that is, the multiline lidar is transversely arranged in the calibration environment. For another example, if the at least two reference points are arranged in the same vertical direction in the curtain, the posture of the multi-line laser beam emitted by the multi-line laser radar and the posture of the at least two reference points in the same vertical direction in the curtain in parallel are controlled to be fixed, and the multi-line laser radar is controlled to be in a static mode, that is, the multi-line laser radar is vertically arranged in the calibration environment. The fixed position of the multiline lidar may be any position on a perpendicular line of the center position of the curtain, which is not specifically limited in the present invention.

After the multi-line laser radar is placed in the calibration environment, the embodiment of the invention can also utilize a distance meter to measure the vertical distance between the multi-line laser radar and the center position of the curtain. And then, calculating a field angle according to the vertical distance and the width of the curtain, determining a camera based on the field angle, and then arranging the camera right above the multi-line laser radar or at other positions capable of completely shooting the whole curtain.

And then, start multi-line laser radar to make two at least laser emitter in the multi-line laser radar send laser beam simultaneously, and form the facula on the curtain, thereby control the camera and carry out image acquisition to the curtain that has the facula, in order to gather facula image. For example, as shown in fig. 2(a), the acquired light spot image is shown, wherein the light spot is marked with 21, the reference point is marked with 22, and the curtain is marked with 23.

It should be noted that, in the embodiment of the present invention, the shape of the reference point may be an arbitrary shape different from the shape of the light spot, for example, as shown in fig. 2(a), the light spot is an ellipse, and the reference point is a rectangle; alternatively, the light spot is circular, the reference point is square, and the like, which is not particularly limited herein.

S102, determining a first distance between adjacent light spots in the light spot image according to the light spot image and the preset distance.

Illustratively, the embodiment of the invention can extract light spots from a light spot image by utilizing Hough transform in image processing, then determine the central pixel point position of each light spot and at least two reference points based on the moment of the image, then determine a first pixel difference value between the central pixel point positions of adjacent light spots in the light spot image, and a second pixel difference value between the central pixel point positions of at least two reference points; and determining a distance scale coefficient according to the second pixel difference value and a preset distance between at least two reference points, and then determining a first distance between adjacent light spots in the light spot image according to the first pixel difference value and the distance scale coefficient. Wherein the distance scaling factor is determined by dividing a preset distance between the at least two reference points by the second pixel difference value. For example, if the preset distance is 1 meter (m) and the second pixel difference is 10, the distance scaling factor is 0.1 when 1/10 is 0.1.

For example, if the multiline lidar is a four-line lidar, then there are 4 spots in the acquired spot image, a1, a2, A3 and a4 respectively, and then the adjacent spots include: a1 and a2, a2 and A3, and A3 and a 4. Wherein, when the adjacent light spots are a1 and a2, and the pixel difference (first pixel difference) between the adjacent light spots a1 and a2 is 5, the distance scaling factor is 0.1, then the first distance between the adjacent light spots a1 and a2 is determined to be 0.5 meters (m); when the adjacent spots are a2 and A3, and the first pixel difference between the adjacent spots a2 and A3 is 4, the range scaling factor is 0.1, then the first distance between the adjacent spots a2 and A3 is determined to be 0.4 m; when the adjacent spots are A3 and a4, and the first pixel difference between the adjacent spots A3 and a4 is 5, the range scaling factor is 0.1, then the first distance between the adjacent spots A3 and a4 is determined to be 0.5 m.

S103, according to the laser beams received by the multi-line laser radar, determining a second distance between a first light spot in the adjacent light spots and the multi-line laser radar, and a third distance between a second light spot in the adjacent light spots and the multi-line laser radar.

And S104, determining the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar according to the first distance, the second distance and the third distance, and calibrating the actual vertical angle between the adjacent laser transmitters.

In the embodiment of the present invention, the second distance between the first spot of the adjacent spots and the multi-line lidar and the third distance between the second spot of the adjacent spots and the multi-line lidar may be determined according to the laser beam emitted by the multi-line lidar and the received laser beam, and the specific determination process refers to the existing scheme and is not described herein in detail.

When the actual vertical angle between the adjacent laser transmitters is specifically determined, a cosine value between the adjacent laser transmitters in the multi-line laser radar can be determined according to the first distance, the second distance between the first light spot in the adjacent light spots and the multi-line laser radar and the third distance between the second light spot in the adjacent light spots and the multi-line laser radar by utilizing a cosine law;

and determining an angle corresponding to the cosine value according to an inverse cosine function, and determining the angle as an actual vertical angle between adjacent laser transmitters in the multi-line laser radar.

For example, as shown in fig. 2(b), if the multi-line lidar 24 is 4 lines, 4 spots are extracted from the spot image, which are a1, a2, A3 and a4, respectively, wherein if the adjacent spots are a1 and a2, and the first distance between a1 and a2 is D11, the second distance between a1 and the multi-line lidar 24 is D12, and the third distance between a2 and the multi-line lidar 24 is D13, a triangle may be formed according to D11, D12 and D13, wherein the included angle between D12 and D13 is the actual vertical angle β between the adjacent laser transmitters a1 and a2 corresponding to the adjacent spots a1 and a2, respectively₁。

Specifically, the actual vertical angle β between adjacent laser emitters a1 and a2 may be calculated by the following equations (1) and (2)₁：

β₁＝arc cosβ₁…………………………………(2)

Similarly, if the adjacent light spots are A2 and A3 and the position between A2 and A3 is the same as that between A3A distance D21, a second distance D13 between the A2 and the multiline lidar 24, and a third distance D22 between the A3 and the multiline lidar 24, form a triangle according to D21, D13 and D22, wherein the included angle between D13 and D22 is the actual vertical angle β between the adjacent laser transmitters a2 and A3 corresponding to the adjacent light spots A2 and A3 respectively₂。

Specifically, the actual vertical angle β between adjacent laser emitters a2 and a3 may be calculated by the following equations (3) and (4)₂：

β₂＝arc cosβ₂………………………………(4)

Similarly, if the adjacent light spots are A3 and a4, and the first distance D31 between A3 and a4, the second distance D22 between A3 and the multi-line lidar 24, and the third distance D32 between a4 and the multi-line lidar 24, a triangle may be formed according to D31, D22, and D32, wherein the included angle between D22 and D32 is the actual vertical angle β between the adjacent laser transmitters A3 and a4 corresponding to the adjacent light spots A3 and a4, respectively₃。

Specifically, the actual vertical angle β between adjacent laser emitters a3 and a4 may be calculated by the following equations (5) and (6)₃：

β₃＝arc cosβ₃………………………………………(6)

Further, after obtaining the actual vertical angle between the adjacent laser emitters, the present embodiment may calibrate the actual vertical angle between the adjacent laser emitters.

Illustratively, embodiments of the present invention may calibrate the actual vertical angle between adjacent laser emitters;

in a first mode

And calibrating the actual vertical angle between the adjacent laser transmitters to a theoretical vertical angle according to the theoretical vertical angle between the adjacent laser transmitters stored by the multi-line laser radar.

Specifically, this embodiment may obtain the theoretical vertical angle between the adjacent laser transmitters stored from the multi-line laser radar, and then determine the theoretical vertical angle between the adjacent laser transmitters according to the identification information of the adjacent laser transmitters. Then, the theoretical vertical angle and the actual vertical angle between the adjacent laser transmitters are compared, and whether the difference between the theoretical vertical angle and the actual vertical angle is within the allowable deviation range is judged. In the embodiment of the present invention, the identification information of the adjacent laser transmitters refers to information for uniquely determining the identity of the laser transmitter, such as the serial number of the laser transmitter.

If the difference value is within the allowable deviation range, determining that the actual vertical angle between the adjacent laser transmitters meets the requirement; if the difference is not within the allowable deviation range, determining that the actual vertical angle between the adjacent laser transmitters is not in accordance with the requirement, and adjusting the actual vertical angle based on the theoretical vertical angle between the adjacent laser transmitters to enable the difference between the adjusted actual vertical angle and the theoretical vertical angle to be within the allowable deviation range.

In the embodiment of the present invention, the allowable deviation range may be set according to actual needs, and is not specifically limited herein. For example, the allowable deviation range is [ +0.03, -0.03] or [ +0.05, -0.05], and the like.

Mode two

And sending the actual vertical angle between the adjacent laser emitters to a user so that the user can calibrate the actual vertical angle of the adjacent laser emitters.

For example, the actual vertical angle between the adjacent laser transmitters may be sent to the user, so that the user obtains the theoretical vertical angle between the corresponding adjacent laser transmitters from the theoretical vertical angle between the adjacent laser transmitters according to the identification information of the adjacent laser transmitters. Then, the theoretical vertical angle and the actual vertical angle between the adjacent laser transmitters are compared, and whether the difference between the theoretical vertical angle and the actual vertical angle is within the allowable deviation range is judged.

Mode III

And replacing the actual vertical angle between the adjacent laser transmitters with the theoretical vertical angle between the adjacent laser transmitters to perform coordinate calculation.

For example, according to a preset communication protocol, the present embodiment records an actual vertical angle between adjacent laser transmitters into the multi-line laser radar, so as to replace a theoretical vertical angle between adjacent laser transmitters for coordinate calculation.

In specific implementation, the actual vertical angle between the adjacent laser transmitters is burnt into the multi-line laser radar according to a preset communication protocol, so that the multi-line laser radar determines the theoretical vertical angle between the adjacent laser transmitters according to the identification information of the adjacent laser transmitters carried in the preset communication protocol.

The preset communication protocol may be any protocol capable of performing data interaction with the multiline lidar, and is not specifically limited herein.

That is to say, after determining the actual vertical angle between the adjacent laser emitter among the multi-line laser radar, burn the actual vertical angle between the adjacent laser emitter to the multi-line laser radar through predetermineeing communication protocol to make the theoretical vertical angle between the adjacent laser emitter of multi-line laser radar based on self storage, calibrate the actual vertical angle between this adjacent laser emitter.

When the actual vertical angle between the adjacent laser transmitters is burnt to the multi-line laser radar by the preset communication protocol, the identification information of the adjacent laser transmitters can be carried in the preset communication protocol, so that the multi-line laser radar can obtain the theoretical vertical angle of the adjacent laser transmitters based on the identification information of the adjacent laser transmitters carried in the preset communication protocol. The identification information of the adjacent laser transmitters refers to information for uniquely determining the laser transmitters, such as laser transmitter numbers and the like.

According to the technical scheme provided by the embodiment of the invention, laser beams emitted by at least two laser emitters in the multi-line laser radar are collected to form a light spot image in a calibration environment, a first distance between adjacent light spots in the light spot image is determined according to the light spot image and a preset distance, a second distance between the first light spot in the adjacent light spots and the multi-line laser radar and a third distance between the second light spot in the adjacent light spots and the multi-line laser radar are determined according to the laser beams received by the multi-line laser radar, then an actual vertical angle between the adjacent laser emitters in the multi-line laser radar is determined according to the first distance, the second distance and the third distance, and the actual vertical angle between the adjacent laser emitters is calibrated. From this, realize carrying out short-term test to the actual vertical angle between the adjacent laser emitter among the multi-line laser radar, and solved because of the error that step motor exists, lead to the problem that vertical angle calibration precision is low between the adjacent laser emitter to the calibration speed and the precision to multi-line laser radar have been improved.

Example two

Fig. 3 is a schematic flow chart of a calibration method for a multiline lidar according to a second embodiment of the present invention, where on the basis of the first embodiment, the present embodiment further optimizes calibration of an actual vertical angle between adjacent laser transmitters according to a theoretical vertical angle between adjacent laser transmitters stored in the multiline lidar. As shown in fig. 3, the method is as follows:

s301, acquiring spot images formed by laser beams emitted by at least two laser emitters in the multi-line laser radar in a calibration environment, wherein the calibration environment comprises at least two reference points with preset distances.

S302, determining a first distance between adjacent light spots in the light spot image according to the light spot image and the preset distance.

And S303, determining a second distance between a first spot of the adjacent spots and the multi-line laser radar and a third distance between a second spot of the adjacent spots and the multi-line laser radar according to the laser beams received by the multi-line laser radar.

S304, determining the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar according to the first distance, the second distance and the third distance.

S305, obtaining the theoretical vertical angle between the adjacent laser transmitters stored by the multi-line laser radar, and subtracting the theoretical vertical angle between the adjacent laser transmitters from the actual vertical angle between the adjacent laser transmitters to obtain a difference value.

For example, if the adjacent laser emitters are a1 and a2, a2 and a3, and a3 and a4, a1 and a2, the actual vertical angle β between them₁A1 and a2, numbered 1 and 2 in the multiline lidar, respectively, and an actual vertical angle β between a2 and a3₂A2 and a3, numbered 2 and 3 in multiline lidar, respectively, and the actual vertical angle β between a3 and a4₃A3 and a4 are numbered 3 and 4 in the multiline lidar respectively, then the theoretical vertical angle β between a1 and a2 is obtained from the multiline lidar according to the numbering of a1, a2, a3 and a4 in the multiline lidar₁', theoretical vertical angle β between a2 and a3₂', and the theoretical vertical angle between a3 and a4, β₃’。

Then, the actual vertical angle between a1 and a2 is β₁Angle β from theoretical vertical₁' subtract to get the difference Δ β₁The actual vertical angle between a2 and a3 is β₂Angle β from theoretical vertical₂' subtract to get the difference Δ β₂And a mixture of a3 and a4True vertical angle β between₃Theoretical vertical angle β between a3 and a4₃' subtract to get the difference Δ β₃。

S306, determining whether the difference value is within an allowable deviation range, if not, executing S307, otherwise, executing S308.

S307, if the difference value is not within the allowable deviation range, adjusting the actual vertical angle between the adjacent laser transmitters to a theoretical vertical angle according to the difference value.

Specifically, if it is determined that the difference is not within the allowable deviation range, the theoretical vertical angle between the adjacent laser transmitters is converted from the polar coordinate system to the rectangular coordinate system in which the actual vertical angle between the adjacent laser transmitters is located, so as to obtain the theoretical positions of the adjacent laser transmitters in the rectangular coordinate system. And then, adjusting the actual positions of the adjacent laser transmitters under the rectangular coordinate system according to the theoretical positions of the adjacent laser transmitters under the rectangular coordinate system, so that the adjusted actual positions are consistent with the theoretical positions, and the purpose of adjusting the actual vertical angles between the adjacent laser transmitters is achieved.

It should be noted that, when the embodiment of the present invention adjusts the actual vertical angle between the adjacent laser emitters, the following situations may be included:

situation one

If the difference value between the actual vertical angle and the theoretical vertical angle between the adjacent laser transmitters is not within the allowable deviation range and has larger deviation with the allowable deviation range, for example, the difference value exceeds a set value, the multiline laser radar is disassembled, and the installation positions of the laser transmitters are readjusted.

The setting value is adaptively set according to the actual application requirement, and is not specifically limited herein.

For example, if the allowable deviation range is [ +0.05, -0.05], the difference between the actual vertical angle and the theoretical vertical angle between adjacent laser transmitters is +0.15, the set value is ± 0.03, it is determined that the difference is not within the allowable deviation range and exceeds the set value ± 0.03, and the difference has a large deviation from the allowable deviation range, a dismantling operation of the multiline lidar is required to readjust the mounting positions of the plurality of laser transmitters on the multiline lidar.

Situation two

And if the difference value between the actual vertical angle and the theoretical vertical angle between the adjacent laser transmitters is not within the allowable deviation range but does not exceed the set value of the allowable deviation range, adjusting the installation position of the laser transmitters on the multi-line laser radar.

And S308, if the difference value is within the allowable deviation range, determining that the actual vertical angle between the adjacent laser transmitters meets the requirement, and not adjusting.

According to the technical scheme provided by the embodiment of the invention, after the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar is determined, the theoretical vertical angle between the adjacent laser transmitters stored by the multi-line laser radar is obtained according to the identification information between the adjacent laser transmitters, and then the actual vertical angle between the adjacent laser transmitters is calibrated according to the theoretical vertical angle between the adjacent laser transmitters. Thereby realize carrying out short-term test to the actual vertical angle between the adjacent laser emitter among the multi-line laser radar, and solved because of the error that step motor exists, lead to the problem that vertical angle calibration precision between the adjacent laser emitter is low to the calibration rate and the precision to multi-line laser radar have been improved.

EXAMPLE III

Fig. 4 is a schematic flowchart of another calibration method for a multiline lidar according to a third embodiment of the present invention, where the method is applicable to a scenario in which a vertical angle between adjacent laser transmitters in the multiline lidar is calibrated, and the method may be implemented by a calibration apparatus for the multiline lidar, where the calibration apparatus may be composed of hardware and/or software, and may be integrated in a calibration system for the multiline lidar. The method specifically comprises the following steps:

s401, acquiring light spot images formed by laser beams emitted by at least two laser emitters in the multi-line laser radar in a calibration environment, wherein the calibration environment comprises at least two reference points with preset distances.

In this embodiment, the multiline laser radar is fixed at a preset pose, so that a light spot formed by a multiline laser beam emitted by the multiline laser radar in the calibration environment is parallel to a straight line formed by at least two reference points.

The implementation process of S401 in the embodiment of the present invention is the same as that of S101 in the first embodiment, and reference is specifically made to the implementation process of S101, which is not described herein in detail.

S402, according to the light spot image and the preset distance, determining a fourth distance between a first light spot in adjacent light spots in the light spot image and the center position of the light spot image and a fifth distance between a second light spot in the adjacent light spots and the center position of the light spot image, and obtaining a vertical distance between the multi-line laser radar and the curtain.

In this embodiment, the central position of the light spot image refers to a central position on the same line with all the light spots in the light spot image.

Illustratively, light spots can be extracted from a light spot image by utilizing Hough transform in image processing, the central pixel point position of each light spot in the light spot image and the central pixel point positions of at least two reference points are determined based on the moment of the image, and the central position of the light spot image is determined; determining a third pixel difference value between the central pixel point position of each light spot in the light spot image and the central position of the light spot image, and a second pixel difference value between the central pixel point positions of at least two reference points; and then determining a distance proportion coefficient according to the second pixel difference value and a preset distance between at least two reference points, and determining a fourth distance between a first light spot in adjacent light spots in the light spot image and the central position of the light spot image and a fifth distance between a second light spot in the adjacent light spots and the central position of the light spot image according to a third pixel difference value and the distance proportion coefficient. Wherein the distance scaling factor is determined by dividing a preset distance between the at least two reference points by the second pixel difference value. For example, if the preset distance is 1 meter (m) and the second pixel difference is 10, the distance scaling factor is 0.1 when 1/10 is 0.1.

For example, if the multi-line lidar is 4 lines, then 4 spots, a1, a2, A3 and a4 respectively, are extracted from the spot image, and then the adjacent spots are determined as: a1 and a2, a2 and A3, A3 and a 4. When the center position of the spot image is Q, the distance scaling factor is 0.3, the first spot of the adjacent spots is a1, the second spot of the adjacent spots is a2, the pixel difference (third pixel difference) between a1 and Q is 8, and the third pixel difference between a2 and Q is 6, then the fourth distance between the first spot a1 and Q is determined as: 2.4m, and the fifth distance between the second light spots A2 and Q is 1.8 m; when the first spot of the adjacent spots is a2, the second spot is A3, and the third pixel difference between a2 and Q is 6, and the third pixel difference between A3 and Q is 7, then the fourth distance between the first spots a2 and Q is determined as: 1.8m, the fifth distance between the second spots A3 and Q is: 2.1 m; when the first spot of the adjacent spots is A3, the second spot is a4, and the third pixel difference between A3 and Q is 7, and the third pixel difference between a4 and Q is 9, then the fourth distance between the first spots A3 and Q is determined as: 2.1, the fifth distance between the second spots a4 and Q is: 2.7 m.

Furthermore, in the embodiment of the invention, the vertical distance between the multi-line laser radar and the curtain can be obtained by using the distance measuring instrument.

S403, determining a sixth distance between the first light spot and the multi-line laser radar according to the fourth distance and the vertical distance, and determining a seventh distance between the second light spot and the multi-line laser radar according to the fifth distance and the vertical distance.

For example, the present embodiment may determine a sixth distance between the first light spot and the multiline lidar according to the fourth distance and the vertical distance, and determine a seventh distance between the second light spot and the multiline lidar according to the fifth distance and the vertical distance by using the pythagorean theorem.

As shown in fig. 5, if the multiline laser radar 51 is 4 lines, the image of the spot is obtained4 spots, a1, a2, A3 and a4, can be extracted. Wherein if the first spot of the adjacent spots is A1, the second spot is A2, and the fourth distance between A1 and the spot image center position Q is S_A1,QAnd a fifth distance between a2 and the spot image center position Q is S_A2,QIf the vertical distance between the multi-line lidar 51 and the curtain 52 is S, the distance (sixth distance) S between the a1 and the multi-line lidar 51 is determined by the pythagorean theorem according to a right triangle formed by three points a1, Q and the multi-line lidar 51_A1,51And determining the distance (seventh distance) S between the A2 and the multi-line laser radar 51 by using the Pythagorean theorem according to a right triangle formed by the three points A2, Q and the multi-line laser radar 51_A2,51。

Specifically, the sixth distance S between a1 and the multiline lidar 51 may be determined by the following equation (7)_A1,51：

Further, a seventh distance S between a2 and multiline lidar 51 may be determined by equation (8) below_A2,51：

Similarly, if the first spot of the adjacent spots is A2, the second spot is A3, and the fourth distance between A2 and the spot image center position Q is S_A2,QAnd a fifth distance between a3 and the spot image center position Q is S_A3,QIf the vertical distance between the multi-line lidar 51 and the curtain 52 is S, the sixth distance S between the a2 and the multi-line lidar 51 is determined by the pythagorean theorem according to a right triangle formed by the three points a2, Q and the multi-line lidar 51_A2,51And determining a seventh distance S between A3 and the multi-line laser radar 51 by using the Pythagorean theorem according to a right triangle formed by three points A3, Q and the multi-line laser radar 51_A3,51。

Specifically, A2 and multiline excitation can be determined by the above equation (8)Sixth distance S between the light radars 51_A2,51。

Further, a seventh distance S between a3 and multiline lidar 51 may be determined by the following equation (9)_A3,51：

Similarly, if the first spot of the adjacent spots is A3, the second spot is A4, and the fourth distance between A3 and the spot image center position Q is S_A3,QAnd a fifth distance between a4 and the spot image center position Q is S_A4,QIf the vertical distance between the multi-line lidar 51 and the curtain 52 is S, the sixth distance S between the A3 and the multi-line lidar 51 is determined by the pythagorean theorem according to a right triangle formed by the three points A3, Q and the multi-line lidar 51_A3,51And determining a seventh distance S between A4 and the multi-line laser radar 51 by using the Pythagorean theorem according to a right triangle formed by three points A4, Q and the multi-line laser radar 51_A4,51。

Specifically, the sixth distance S between a3 and the multiline lidar 51 may be determined by the above equation (9)_A3,51。

Further, a seventh distance S between a4 and multiline lidar 51 may be determined by equation (10) below_A4,51：

S404, determining a first included angle between the sixth distance and the vertical distance according to the fourth distance, the vertical distance and the sixth distance, and determining a second included angle between the seventh distance and the vertical distance according to the fifth distance, the vertical distance and the seventh distance.

In this embodiment, when a first included angle between a sixth distance and a vertical distance and a second included angle between a seventh distance and the vertical distance are determined, a first cosine value between the sixth distance and the vertical distance is determined according to the fourth distance, the vertical distance and the sixth distance by using a cosine theorem, and a second cosine value between the seventh distance and the vertical distance is determined according to the fifth distance, the vertical distance and the seventh distance;

and determining a first included angle corresponding to the first cosine value and a second included angle corresponding to the second cosine value according to an inverse cosine function.

Continuing with the above description of the example shown in fig. 5, assuming that the adjacent light spots are a1 and a2, where the first light spot is a1 and the second light spot is a2, in the right triangle formed by a1, Q and the multi-line lidar 51, the included angle between the line segment where a1 and the multi-line lidar 51 are located and the line segment where Q and the multi-line lidar 51 are located is the first included angle θ₁(ii) a In the right triangle formed by the A2, the Q and the multi-line laser radar 51, the included angle between the line segment of the A2 and the multi-line laser radar 51 and the line segment of the Q and the multi-line laser radar 51 is the second included angle theta₂。

Specifically, the first included angle θ can be determined by the following equations (11) and (12)₁：

θ₁＝arcCOSθ₁…………………………………………(12)

Further, the second angle θ can be determined by the following equations (13) and (14)₂：

θ₂＝arcCOSθ₂……………………………………(14)

Similarly, if the adjacent light spots are a2 and A3, the first light spot is a2, and the second light spot is A3, then in the right triangle formed by a2, Q and the multi-line lidar 51, the line segment where a2 and the multi-line lidar 51 are located, and the line segment where Q and the multi-line lidar 51 are locatedThe angle between the line segments is the first angle theta₂(ii) a In the right triangle formed by the A3, the Q and the multi-line laser radar 51, the included angle between the line segment of the A3 and the multi-line laser radar 51 and the line segment of the Q and the multi-line laser radar 51 is the second included angle theta₃。

Specifically, the first included angle θ can be determined by the above equations (13) and (14)₂：

Further, the second angle θ can be determined by the following equations (15) and (16)₃：

θ₃＝arcCOSθ₃……………………………………(16)

Similarly, if the adjacent light spots are A3 and a4, where the first light spot is A3 and the second light spot is a4, in the right triangle formed by A3, Q and the multi-line lidar 51, an included angle between a line segment of the A3 and the multi-line lidar 51 and a line segment of the Q and the multi-line lidar 51 is the first included angle θ₃(ii) a In the right triangle formed by the A4, the Q and the multi-line laser radar 51, the included angle between the line segment of the A4 and the multi-line laser radar 51 and the line segment of the Q and the multi-line laser radar 51 is the second included angle theta₄。

Specifically, the first included angle θ can be determined by the above equations (15) and (16)₃：

Further, the second angle θ can be determined by the following equations (17) and (18)₄：

θ₄＝arcCOSθ₄……………………………………(18)

S405, determining the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar according to the first included angle and the second included angle, and calibrating the actual vertical angle between the adjacent laser transmitters.

Specifically, in this embodiment, the difference value or the sum value of the included angles between the first included angle and the second included angle may be determined as the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar.

Continuing with the above example of fig. 5, assume that the adjacent spots are a1 and a2, and from the example in S404, in the right triangle formed by a1, Q and the multiline lidar 51, ∠ a1,51, Q ═ θ₁In a right triangle formed by a2, Q and the multiline laser radar 51, ∠ a2,51, Q ═ θ₂Then theta₁-θ₂＝θ₁₂Theta of₁₂I.e., the actual vertical angle between adjacent laser emitters a1 and a 2.

Similarly, assume that the adjacent spots are a2 and A3, and from the example in S404, in the right triangle formed by a2, Q and the multiline lidar 51, ∠ a2,51, Q ═ θ₂In a right triangle formed by A3, Q and the multiline laser radar 51, ∠ A3,51, Q ═ θ₃Then theta₂+θ₃＝θ₂₃Theta of₂₃I.e., the actual vertical angle between adjacent laser emitters a2 and a 3.

Similarly, assume that the adjacent spots are A3 and a4, and from the example in S404, in the right triangle formed by A3, Q and the multiline lidar 51, ∠ A3,51, Q ═ θ₃In a right triangle formed by a4, Q and the multiline laser radar 51, ∠ a4,51, Q ═ θ₄Then | θ₃-θ₄|＝θ₃₄Theta of₃₄I.e., the actual vertical angle between adjacent laser emitters a3 and a 4.

Further, after obtaining the actual vertical angle between the adjacent laser emitters, the actual vertical angle between the adjacent laser emitters may be calibrated.

in a first mode

Mode two

For example, the actual vertical angle between the adjacent laser transmitters may be sent to the user, so that the user may obtain the theoretical vertical angle between the corresponding adjacent laser transmitters from the theoretical vertical angle between the adjacent laser transmitters required by the user according to the identification information of the adjacent laser transmitters. Then, the theoretical vertical angle and the actual vertical angle between the adjacent laser transmitters are compared, and whether the difference between the theoretical vertical angle and the actual vertical angle is within the allowable deviation range is judged.

Mode III

According to the technical scheme provided by the embodiment of the invention, a light spot image formed in a calibration environment is acquired by collecting laser beams emitted by at least two laser emitters in a multi-line laser radar, a fourth distance between a first light spot in adjacent light spots in the light spot image and the central position of the light spot image and a fifth distance between a second light spot in the adjacent light spots and the central position of the light spot image are determined according to the light spot image and a preset distance, vertical processing between the multi-line laser radar and a curtain is acquired, a sixth distance between the first light spot and the multi-line laser radar is determined according to the fourth distance and the vertical distance, a seventh distance between the second light spot and the multi-line laser radar is determined according to the fifth distance and the vertical distance, a first included angle between the sixth distance and the vertical distance is determined according to the fourth distance, the vertical distance and the sixth distance, and a first included angle between the sixth distance and the vertical distance is determined according to the fifth distance, Determining a second included angle between the seventh distance and the vertical distance; and determining the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar according to the first included angle and the second included angle, and calibrating the actual vertical angle between the adjacent laser transmitters. From this, realize carrying out short-term test to the actual vertical angle between the adjacent laser emitter among the multi-line laser radar, and solved because of the error that step motor exists, lead to the problem that vertical angle calibration precision is low between the adjacent laser emitter to the calibration speed and the precision to multi-line laser radar have been improved.

Example four

Fig. 6 is a schematic structural diagram of a calibration apparatus for a multiline lidar according to a fourth embodiment of the present invention. As shown in fig. 6, a calibration apparatus 600 for a multiline lidar according to an embodiment of the present invention includes: a spot image acquisition module 610, a first distance determination module 620 and a first angle determination and calibration module 630.

The system comprises a light spot image acquisition module 610, a calibration environment and a control module, wherein the light spot image acquisition module 610 is used for acquiring light spot images formed in the calibration environment by laser signals emitted by at least two laser emitters in the multi-line laser radar, and the calibration environment comprises at least two reference points with preset distances;

a first distance determining module 620, configured to determine a first distance between adjacent light spots in the light spot image according to the light spot image and the preset distance;

the first distance determining module 620 is further configured to determine, according to the laser beam received by the multi-line lidar, a second distance between a first spot of the adjacent spots and the multi-line lidar, and a third distance between a second spot of the adjacent spots and the multi-line lidar;

a first angle determining and calibrating module 630, configured to determine an actual vertical angle between adjacent laser transmitters in the multi-line lidar according to the first distance, the second distance, and the third distance, and calibrate the actual vertical angle between the adjacent laser transmitters.

As an optional implementation manner of the embodiment of the present invention, the multiline laser radar is fixed at a preset pose, so that a light spot formed by a multiline laser beam emitted by the multiline laser radar in the calibration environment is parallel to a straight line formed by at least two reference points.

As an optional implementation manner of the embodiment of the present invention, the first distance determining module 620 is specifically configured to:

extracting light spots from the light spot image, and determining the position of each light spot and the central pixel points of at least two reference points;

determining a first pixel difference value between the positions of central pixel points of adjacent light spots in the light spot image and a second pixel difference value between the positions of the central pixel points of at least two reference points;

determining a distance scale factor according to the second pixel difference value and a preset distance between at least two reference points;

and determining a first distance between adjacent light spots in the light spot image according to the first pixel difference value and the distance scale coefficient.

As an optional implementation manner of the embodiment of the present invention, the calibration environment is an environment provided with a curtain; the at least two reference points are disposed on the curtain.

As an optional implementation manner of the embodiment of the present invention, the first angle determining and calibrating module 630 is specifically configured to:

determining cosine values between adjacent laser transmitters in the multi-line laser radar according to the first distance, the second distance and the third distance by using a cosine law;

calibrating the actual vertical angle between the adjacent laser transmitters to a theoretical vertical angle according to the theoretical vertical angle between the adjacent laser transmitters stored by the multi-line laser radar; alternatively, the first and second electrodes may be,

sending the actual vertical angle between the adjacent laser transmitters to a user so that the user can calibrate the actual vertical angle of the adjacent laser transmitters; alternatively, the first and second electrodes may be,

As an optional implementation manner of the embodiment of the present invention, the apparatus 600 further includes: a data burning module;

the data burning module is used for burning the actual vertical angle between the adjacent laser transmitters into the multi-line laser radar according to a preset communication protocol so as to replace the theoretical vertical angle between the adjacent laser transmitters for coordinate calculation.

As an optional implementation manner of the embodiment of the present invention, the first angle determining and calibrating module 630 is further configured to:

the method comprises the following steps of (1) making a difference between a theoretical vertical angle between adjacent laser transmitters and an actual vertical angle between the adjacent laser transmitters to obtain a difference value;

determining whether the difference is within an allowable deviation range;

and if the difference is not within the allowable deviation range, adjusting the actual vertical angle between the adjacent laser transmitters to a theoretical vertical angle according to the difference.

It should be noted that the explanation of the embodiment of the calibration method for a multiline laser radar is also applicable to the calibration device for a multiline laser radar of this embodiment, and the implementation principle is similar, and is not repeated here.

EXAMPLE five

Fig. 7 is a schematic structural diagram of a calibration apparatus for a multiline lidar according to a fifth embodiment of the present invention. As shown in fig. 7, a calibration apparatus 700 for a multiline lidar according to an embodiment of the present invention includes: a spot image acquisition module 610, a second distance determination module 710, an included angle determination module 720, and a second angle determination and calibration module 730.

The system comprises a light spot image acquisition module 610, a calibration environment and a control module, wherein the light spot image acquisition module 610 is used for acquiring light spot images formed in the calibration environment by laser beams emitted by at least two laser emitters in the multi-line laser radar, and the calibration environment comprises at least two reference points with preset distances;

a second distance determining module 710, configured to determine, according to the light spot image and a preset distance, a fourth distance between a first light spot of adjacent light spots in the light spot image and the center position of the light spot image, and a fifth distance between a second light spot of the adjacent light spots and the center position of the light spot image, and obtain a vertical distance between the multi-line laser radar and the curtain;

the second distance determining module 710 is further configured to determine a sixth distance between the first light spot and the multiline lidar according to the fourth distance and the vertical distance, and determine a seventh distance between the second light spot and the multiline lidar according to the fifth distance and the vertical distance;

an included angle determining module 720, configured to determine a first included angle between the first light spot and the central position of the light spot image according to the fourth distance, the vertical distance, and the sixth distance, and determine a second included angle between the second light spot and the central position of the light spot image according to the fifth distance, the vertical distance, and the seventh distance;

and a second angle determining and calibrating module 730, configured to determine an actual vertical angle between adjacent laser emitters in the multi-line laser radar according to the first included angle and the second included angle.

As an optional implementation manner of the embodiment of the present invention, the second distance determining module 710 is specifically configured to:

extracting light spots from the light spot image, and determining the position of a central pixel point of each light spot and at least two reference points and the central position of the light spot image;

determining a third pixel difference value between the central pixel point position of each light spot in the light spot image and the central position of the light spot image, and a second pixel difference value between the central pixel point positions of at least two reference points;

and determining a fourth distance between a first light spot in adjacent light spots in the light spot image and the central position of the light spot image and a fifth distance between a second light spot in the adjacent light spots and the central position of the light spot image according to the third pixel difference and the distance scale coefficient.

and determining a sixth distance between the first light spot and the multi-line laser radar according to the fourth distance and the vertical distance by utilizing the pythagorean theorem, and determining a seventh distance between the second light spot and the multi-line laser radar according to the fifth distance and the vertical distance.

As an optional implementation manner of the embodiment of the present invention, the included angle determining module 720 is specifically configured to:

determining a first cosine value between the sixth distance and the vertical distance according to the fourth distance, the vertical distance and the sixth distance by using a cosine theorem, and determining a second cosine value between the seventh distance and the vertical distance according to the fifth distance, the vertical distance and the seventh distance;

As an optional implementation manner of the embodiment of the present invention, the second angle determining and calibrating module 730 is specifically configured to:

and determining the difference value or the sum value of the included angles between the first included angle and the second included angle as the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar.

As an optional implementation manner of the embodiment of the present invention, the second angle determining and calibrating module 730 is further configured to:

determining whether the difference is within an allowable deviation range;

According to the technical scheme provided by the embodiment of the invention, the actual vertical angle between the adjacent laser transmitters in the multi-line laser radar is quickly detected, and the problem of low calibration precision of the vertical angle between the adjacent laser transmitters due to errors of the stepping motor is solved, so that the calibration speed and the calibration precision of the multi-line laser radar are improved.

EXAMPLE six

Fig. 8 is a schematic structural diagram of a calibration system of a multiline lidar according to a fourth embodiment of the present invention. As shown in fig. 8, a calibration system 800 for a multiline lidar according to an embodiment of the present invention includes: multiline lidar 810, camera 820, and calibration device 830;

the multi-line laser radar 810 is used for emitting a plurality of laser beams and receiving the laser beams;

the camera 820 is used for acquiring spot images formed by laser beams emitted by at least two laser emitters in the multiline laser radar in a calibration environment;

the calibration apparatus 830 includes a memory 831 and a processor 832, wherein the memory 831 stores a computer program, so that the processor 832 implements the calibration method of the multiline lidar according to the embodiment of the present invention when executing the computer program.

The calibration device in this embodiment specifically refers to the calibration device for the multiline lidar in the fourth or fifth embodiment.

It should be noted that the explanation of the embodiment of the calibration method for a multiline laser radar is also applicable to the calibration system for a multiline laser radar of this embodiment, and the implementation principle is similar, and is not repeated here.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method of calibrating a multiline lidar comprising:

2. The method of claim 1, further comprising:

and fixing the multi-line laser radar at a preset pose so that a light spot formed by the multi-line laser beam emitted by the multi-line laser radar in the calibration environment is parallel to a straight line formed by at least two reference points.

3. The method according to claim 1, wherein the determining a first distance between adjacent spots in the spot image according to the spot image and the preset distance specifically comprises:

4. A method according to any of claims 1-3, wherein the calibration environment is an environment provided with a curtain; the at least two reference points are disposed on the curtain.

5. The method according to claim 1, wherein the determining the actual vertical angle between adjacent laser emitters in the multiline lidar from the first distance, the second distance and the third distance comprises:

6. The method of claim 1, wherein said calibrating the actual vertical angle between the adjacent laser emitters comprises:

7. The method according to claim 6, wherein the calibrating the actual vertical angle between the adjacent laser emitters to a theoretical vertical angle in accordance with the stored theoretical vertical angles between the adjacent laser emitters by the multiline lidar comprises:

determining whether the difference is within an allowable deviation range;

8. A method of calibrating a multiline lidar comprising:

9. A multiline lidar calibration device comprising:

10. A system for calibrating a multiline lidar comprising:

calibration apparatus comprising a memory and a processor, the memory having stored therein a computer program such that the processor, when executing the computer program, implements a method of calibrating a multiline lidar according to any of claims 1-8.