CN114415189A

CN114415189A - Laser radar system and calibration method thereof

Info

Publication number: CN114415189A
Application number: CN202011084394.5A
Authority: CN
Inventors: 郑凯; 张海武; 疏达; 李�远
Original assignee: Benewake Beijing Co Ltd
Current assignee: Benewake Beijing Co Ltd
Priority date: 2020-10-12
Filing date: 2020-10-12
Publication date: 2022-04-29
Also published as: WO2022077711A1

Abstract

The embodiment of the invention discloses a laser radar system and a calibration method thereof, relates to the technical field of laser radars, and aims to simply and quickly perform calibration operation. The laser radar system includes: the device comprises a laser emitting unit, a scanning unit, a receiving unit and a control unit; the laser emission unit comprises a light source and a collimator positioned on a light emergent path of the light source, the light source is provided with more than two laser output channels, and laser beams output by different laser output channels are output in a divergent mode after being collimated by the collimator; and/or the receiving unit comprises a photoelectric detector, the photoelectric detector is provided with more than two pixels, and a converging lens is arranged on the light receiving path of the more than two pixels, so that the more than two pixels receive the light reflected back by the target through the converging lens. The invention is suitable for detecting the distance of the target.

Description

Laser radar system and calibration method thereof

Technical Field

The invention relates to the technical field of laser radars, in particular to a laser radar system and a calibration method thereof.

Background

The laser radar is a radar system that detects a characteristic amount such as a position and a velocity of a target by emitting a laser beam. The working principle is to transmit a detection signal (laser beam) to a target, then compare the received signal (target echo) reflected from the target with the transmitted detection signal, and after appropriate processing, obtain the relevant information of the target, such as target distance, orientation, height, speed, attitude, even shape, etc.

At present, the application of the multiline laser radar based on mechanical rotation scanning is wide. The multiline laser radar is a radar which generates a plurality of scanning lines by scanning a laser beam emitted by a laser source once. In the multiline laser radar, a collimator needs to be configured for each laser beam in a laser transmitting unit, and a converging lens needs to be configured for each target echo in a receiving unit. When the optical axes of the laser emitting unit and the laser receiving unit are calibrated, the number of the laser beams emitted by the laser source is large, and the number of the configured collimators and the number of the converging lenses are correspondingly large, so that the calibration difficulty is high, and the calibration time is long.

Disclosure of Invention

In view of this, embodiments of the present invention provide a laser radar system and a calibration method thereof, which can perform calibration operation simply and quickly.

In a first aspect, an embodiment of the present invention provides a laser radar system, including: the laser scanning device comprises a laser emitting unit, a scanning unit, a receiving unit and a control unit, wherein the control unit controls the laser emitting unit to emit laser, and the laser is emitted after being scanned by the scanning unit so as to be received by the receiving unit after being reflected by a target; the laser emission unit comprises a light source and a collimator positioned on a light emergent path of the light source, the light source is provided with more than two laser output channels, and laser beams output by different laser output channels are output in a divergent mode after being collimated by the collimator; and/or the receiving unit comprises a photoelectric detector, the photoelectric detector is provided with more than two pixels, and a converging lens is arranged on the light receiving path of the more than two pixels, so that the more than two pixels receive the light reflected back by the target through the converging lens.

According to a specific implementation manner of the embodiment of the invention, the light source and the collimator are connected together and can rotate together to calibrate the optical axes of the laser emitting unit and the receiving unit.

According to a specific implementation manner of the embodiment of the present invention, the photodetector can move and/or rotate relative to the converging lens to calibrate the optical axes of the laser emitting unit and the receiving unit.

According to a specific implementation manner of the embodiment of the invention, the photodetector and the converging lens can move and/or rotate together to calibrate the optical axes of the laser emitting unit and the receiving unit.

According to a specific implementation manner of the embodiment of the invention, the laser emitted by the light source is pulse laser; the outlets of the more than two laser output channels are linearly arranged in the vertical direction.

According to a specific implementation manner of the embodiment of the invention, beam included angles are formed between different beams output by the collimator in the vertical direction; and the scanning included angle of the scanning unit in the vertical direction is smaller than the minimum included angle in the light beam included angles. The light beams output by the collimator are provided with fixed included angles, the included angles among different light beams are enabled to be in the vertical direction by adjusting the rotation direction of the collimator along the optical axis, and the collimator is fixed by a clamping piece of the collimator after being adjusted.

According to a specific implementation manner of the embodiment of the invention, the scanning included angle of the scanning unit in the vertical direction is adjustable.

According to a specific implementation manner of the embodiment of the invention, the number of the pixels is the same as the number of the laser output channels, and the more than two pixels correspond to the more than two laser output channels one by one.

In a second aspect, an embodiment of the present application further provides a calibration method that can be used in any one of the foregoing laser radar systems, where the calibration method includes:

rotating the light source together with the collimator, and adjusting the position of the light beam output by the collimator, which is incident on the scanning unit; and/or the presence of a gas in the gas,

and adjusting the positions of the more than two pixels relative to the converging lens, or rotating or moving the more than two pixels and the converging lens together, so that the light beams emitted after being scanned by the scanning unit are accurately received by the receiving unit after being reflected by the target.

According to a specific implementation manner of the embodiment of the invention, beam included angles are formed between different beams output by the collimator in the vertical direction; the calibration method further comprises: and adjusting the scanning included angle of the scanning unit in the vertical direction so as to enable the scanning included angle to be smaller than the minimum included angle in the light beam included angles.

According to the laser radar system and the calibration method thereof provided by the embodiment of the invention, more than two pulse lasers emitted by the laser emission unit are output in a collimating way only through one collimator, and/or only one converging lens is arranged on the light receiving path of more than two pixels of the receiving unit, so that the number of the required collimators and/or converging lenses is greatly reduced, and thus, when the optical axis between the laser emission unit and the receiving unit is calibrated, the complexity of operation can be reduced, and the calibration operation is simpler and faster.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic diagram of a lidar system according to an embodiment of the present disclosure.

Fig. 2 is a schematic diagram of an end face of a fiber laser according to an embodiment of the present application.

Fig. 3 is a schematic diagram of a laser transmitter integrated with a fiber laser and a collimator.

FIG. 4 is a diagram of an APD photodetector according to an embodiment of the present application.

Fig. 5 is a schematic diagram of a receiving unit receiving a pulsed laser according to an embodiment of the present application.

Fig. 6 is a schematic diagram of laser emission of a lidar system according to an embodiment of the present application.

Fig. 7 is a schematic diagram of a scanning trajectory of a lidar system according to an embodiment of the present disclosure.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the described embodiments are only some embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the application aims to provide a laser radar system capable of simply and quickly performing calibration operation and a calibration method thereof.

Fig. 1 is a schematic diagram of a lidar system according to an embodiment of the present application, and referring to fig. 1, a lidar system 100 according to an embodiment of the present application includes: the laser scanning device comprises a laser emitting unit 200, a scanning unit 300, a receiving unit 400 and a control unit 500, wherein the control unit 500 controls the laser emitting unit 200 to emit laser, and the laser emitted by the laser emitting unit 200 is emitted after being scanned by the scanning unit 300 so as to be reflected by a target and then received by the receiving unit 400.

And a laser emitting unit 200 for generating pulse laser, collimating the pulse laser, and outputting the collimated pulse laser. The laser device comprises a light source and a collimator positioned on a light emitting path of the light source, wherein the light source is provided with more than two laser output channels, and laser beams output by different laser output channels are output after being collimated by the collimator. Each laser beam is output through one optical fiber, a plurality of optical fibers corresponding to a plurality of laser beams are connected to one optical fiber output connector, and the optical fiber connector is connected with one collimator to realize the collimation output of a plurality of light beams.

The light source may be a semiconductor light source, a fiber coupled light source, or any other type of light source. In terms of wavelength, the light source may be a light source having a wavelength of 905nm, 1550nm, or the like. In one example, the light source employs a narrow pulse laser fiber laser having a wavelength of 1550 nm.

The light source can emit more than two beams of pulse laser. The light source emits more than two beams of pulse laser which are respectively output through different laser output channels.

In one example, the light source comprises a light emitting source. One light emitting source may emit a beam of pulsed laser light. One pulse laser beam is split into two or more pulse laser beams by a beam splitter (e.g., a beam splitter). And outputting more than two beams of pulse laser obtained after beam splitting through different laser output channels respectively.

In another example, the light source includes more than two light emitting sources. Each luminous source can emit a beam of pulse laser, and correspondingly, more than two luminous sources can emit more than two beams of pulse laser simultaneously. More than two beams of pulse laser emitted by more than two luminous sources at the same time are respectively output through different laser output channels.

When the light source includes more than two light-emitting sources, the spacing between the light-emitting sources is specifically arranged. In one embodiment, the distance between the light sources is fixed, for example, 100 and 300 μm, and the light sources are arranged in a straight line, a triangle, or a rectangle.

In order to provide laser radar system 100 with a higher vertical resolution (also referred to as vertical angular resolution), the outlets of the two or more laser output channels of laser emitting unit 200 may be linearly arranged in a vertical direction (e.g., vertical direction), which facilitates scanning unit 300 to form more scanning tracks in the vertical direction, thereby increasing the vertical resolution of laser radar system 100. The vertical resolution refers to the angular resolution of the adjacent light rays in the vertical direction, the vertical resolution is smaller than or equal to the scanning included angle, the vertical resolution at the top and the bottom of the trace graph formed by scanning in fig. 7 is equal to the scanning included angle, and the vertical resolution at the middle part is smaller than the scanning included angle due to the staggered superposition of the 2 channel traces.

In order to make the laser radar system 100 have a higher vertical resolution and at the same time, the size of the light source in the vertical direction is not excessively increased, when the two or more pulse laser beams emitted by the light source are output in a divergent manner after being collimated by the collimator, a preset beam angle is formed between different beams output by the collimator in the vertical direction, and the beam angle is greater than 0.5 degrees and less than 5 degrees.

Accordingly, the scanning angle of the scanning unit 300 in the vertical direction is smaller than the smallest beam angle among the beam angles. Thus, the middle portion of the scanning trace pattern formed by scanning by the scanning unit 300 may have a higher vertical resolution than the top and bottom portions.

The scan angle of the scan unit 300 in the vertical direction can be dynamically adjusted to achieve dynamic adjustment of the vertical resolution of the lidar system 100. Specifically, the control unit 500 may dynamically adjust the vibration amplitude of the galvanometer corresponding to each line in the scanning unit 300, so as to dynamically adjust the scan line angle of the scanning unit 300 in the vertical direction, thereby dynamically adjusting the vertical resolution of the laser radar system 100.

The scanning unit 300 includes a polygon mirror and a galvanometer. The polygon prism is used for realizing scanning in the horizontal direction, the vibrating mirror is used for realizing scanning in the vertical direction, and the combination of the polygon prism and the vibrating mirror can realize scanning detection of the laser radar system 100 in the horizontal direction and the vertical direction. The galvanometer can be a galvanometer driven by a motor or a galvanometer driven by an MEMS (micro electro mechanical system); the prism may have a plurality of reflecting surfaces such as 2 surfaces, 3 surfaces, 4 surfaces, and 6 surfaces.

The receiving unit 400 includes a photo detector having more than two pixels, and a converging lens is disposed on a light receiving path of the more than two pixels, so that the more than two pixels receive light reflected by the target through the converging lens. The photodetector may be a photodetector made of different materials such as silicon and InGaAs. The photodetector may be a PIN photodetector, an apd (avalanche Photo diode) photodetector (also called avalanche photodetector), a geiger mode photodetector, or the like. From the number and arrangement of the pixels, the photodetector may be a line photodetector or an area array photodetector. The pitch of each pixel of the photodetector is specifically arranged. In one embodiment, the arrangement of the pixels of the photodetector is a line array arrangement or an area array arrangement, and the pitch of each pixel may be a fixed equal pitch, for example, 500-1000 μm.

In order to achieve a high accuracy of the detection laser of the laser radar system 100, when the light sources (or ports of the laser output channels) of the laser emitting unit 200 are arranged in a line array or an area array, the pixels of the photodetectors corresponding to the receiving unit 400 are also arranged in a line array or an area array, and each light source (or laser output channel) corresponds to each pixel. For example, there are two laser output channels of the light source in the laser emitting unit 200, which are L1 and L2; there are also two pixels on the photodetector, R1 and R2, R1 corresponding to L1, and R2 and L2. The laser beam emitted from the L1 channel and collimated by the collimator is emitted to the target after being scanned by the scanning unit 300, reflected by the target, and received by the pixel element R1; the laser beam emitted from the L2 channel and collimated by the collimator is scanned by the scanning unit 300, emitted to the target, reflected by the target, and received by the pixel element R2.

The receiving unit 400 may further include a signal conditioning circuit, configured to process the pulse echo received by the photodetector, which is reflected by the target and converged by the converging lens, such as performing denoising or signal enhancement processing. The pulse echo processed by the signal conditioning circuit is output to the control unit 500, and the control unit 500 calculates the target distance according to the time that the pulse echo lags behind the transmission pulse.

And the control unit 500 is configured to control the laser emitting unit 200 to emit pulse laser, then control the scanning unit 300 to scan to realize scanning detection of a target, and finally realize point cloud display of the laser radar by reading an echo signal of the receiving unit 400 and calculating a distance. The control unit 500 may also be used to calculate the strength information of the echo signal returned by the target.

When the laser radar system 100 starts to work, the control unit 500 controls the laser emitting unit 200 to emit pulse laser, the pulse laser is reflected by the galvanometer and the polygon prism and then emitted to a target, the pulse laser is reflected by the target and then received by the photodetector of the receiving unit 400 along the prism and the galvanometer and generates an echo signal, the echo signal is processed by the signal conditioning circuit of the receiving unit 400 and then output to the control unit 500, the control unit 500 calculates the target distance according to the time that the pulse echo lags behind the emitted pulse, meanwhile, the control unit 500 can acquire angle data of the galvanometer and the prism in real time and can acquire three-dimensional point cloud information of the target through calculation, the control unit 500 can calculate the point cloud information of the target in real time through continuous scanning of the galvanometer and the prism and finally sends the point cloud data to the upper computer to display the target in real time.

The optical axis alignment between the laser emitting unit 200 and the receiving unit 400 may be performed by changing the positions of the light emitting source and the collimator, so that the laser beam emitted from the laser emitting unit 200 is scanned by the scanning unit 300, emitted to the target, reflected by the target, and then accurately received by the receiving unit 400. Specifically, the optical axis of the light source or the collimator may be used as a rotation axis, and the light source and the collimator are rotated or moved in a three-dimensional space, so as to calibrate the optical axes of the laser emitting unit 200 and the receiving unit 400.

Compared with the case that each pulse laser beam is respectively provided with one collimator, in the embodiment, more than two pulse laser beams are output by collimation of only one collimator, so that the operation complexity can be reduced when the optical axis between the laser emitting unit 200 and the receiving unit 400 is calibrated, and the calibration operation is simpler and faster.

To further simplify the calibration operation, the light-emitting source and the collimator may be adjusted in position as a whole. In one example, the collimator and the light emitting source are coupled (or integrated) together so that the light emitting source and the collimator as a whole can be positionally adjusted.

In addition to the optical axis alignment between the laser emitting unit 200 and the receiving unit 400 by changing the positions of the light emitting source and the collimator, the optical axis alignment between the laser emitting unit 200 and the receiving unit 400 may also be performed by changing the positions of the photodetector and/or the condensing lens.

In one example, the photodetector can move and/or rotate relative to the converging lens to calibrate the optical axes of the laser emitting unit 200 and the receiving unit 400, so that the laser beam emitted by the laser emitting unit 200 is scanned by the scanning unit 300 and emitted to the target, and after being reflected by the target, the laser beam is accurately received by the receiving unit 400. The movement of the photodetector relative to the converging lens may be a movement in three dimensions (approaching or departing, moving left and right, moving up and down, etc.). The rotation of the photodetector relative to the converging lens may be a rotation using an optical axis of the converging lens as a rotation axis.

In another example, the photodetector and the condensing lens can move and/or rotate together to calibrate the optical axes of the laser emitting unit 200 and the receiving unit 400, so that the laser beam emitted from the laser emitting unit 200 is scanned by the scanning unit 300 and emitted to the target, and after being reflected by the target, is accurately received by the receiving unit 400. The movement of the photodetector and the condensing lens may be a movement in a three-dimensional space (forward or backward, left or right movement, up or down movement, etc.). The rotation of the photodetector and the converging lens can also be carried out by taking the optical axis of the converging lens as a rotating shaft.

Compared with the case that each image element is respectively provided with one converging lens, in the embodiment, only one converging lens exists on the light receiving paths of more than two image elements, so that when the optical axis between the laser emitting unit 200 and the receiving unit 400 is calibrated, the complexity of operation can be reduced, and the calibration operation is simpler and faster.

In the above-described embodiment, the optical axis alignment between the laser emitting unit 200 and the receiving unit 400 can be performed by changing the positions of the light emitting source and the collimator, and by changing the positions of the photodetector and/or the condensing lens. The embodiment of the present application is not limited thereto, and in other embodiments, the optical axis alignment between the laser emitting unit 200 and the receiving unit 400 may be performed only by changing the positions of the light emitting source and the collimator. In this case, more than two beams of pulse laser emitted by the light source need to be output by collimation of only one collimator; more than two pixels of the photoelectric detector can be configured with a convergent lens together or with respective convergent lenses respectively. In still other embodiments, optical axis alignment between the laser emitting unit 200 and the receiving unit 400 may be performed only by changing the position of the photodetector and/or the condensing lens. In this case, more than two pixels of the photodetector need only be configured with a converging lens; and more than two beams of pulse laser emitted by the light source can be output through collimation of one collimator or can be output through collimation of different collimators respectively.

The laser radar system of the present application is described in detail below by taking a specific embodiment as an example:

referring to fig. 1, laser radar system 100 of the present embodiment includes: a laser emitting unit 200, a scanning unit 300, a receiving unit 400, and a control unit 500.

The light source of the laser emitting unit 200 is a narrow pulse laser fiber laser with a wavelength of 1550 nm. Fig. 2 is a schematic diagram of an end face of a fiber head of the fiber laser in this embodiment, referring to fig. 2, a fiber head 201 of the fiber laser has two

laser output channels

202a and 202b, and the two

laser output channels

202a and 202b are arranged at a specific interval, for example, a fixed interval is 100 microns or 300 microns.

Fig. 3 is a schematic diagram of a laser transmitter integrated with a fiber laser and a collimator, and referring to fig. 3, laser output through two

laser output channels

202a and 202b of a fiber head of the fiber laser forms two beams of laser 204a and 204b with a fixed included angle after being output through one collimator.

The laser transmitter 200 integrated with the fiber laser and the collimator is fixed on a laser transmitting structural member (not shown in the figure), and the rotation angle can be adjusted along the central optical axis of the laser transmitter 200, so that two beams of emitted laser 204a and 204b can be detected by two pixels of the receiving APD photoelectric detector.

The center-to-center spacing of the two

laser output channels

202a and 202b matches the center-to-center spacing of the two pixels of the APD photodetector of receiving unit 400.

The galvanometer of the scanning unit 300 is driven by a motor, and the scanning mode, the scanning angle range and the scanning frequency of the galvanometer are controlled by the control unit 500; the prism adopts six prisms, and the scanning optical angle of each surface is more than 90 degrees.

The photodetector of the receiving unit 400 employs an APD photodetector based on InGaAs. Fig. 4 is a schematic diagram of an APD photodetector in this embodiment. In fig. 4, APD photodetector 401 includes two

pixels

402a and 402b arranged in a linear pattern, where the two

pixels

402a and 402b are arranged at a specific center-to-center spacing, for example, the spacing between the two pixels is fixed at 500 microns and 1000 microns.

Fig. 5 is a schematic diagram of the receiving unit receiving the pulsed laser in this embodiment. Referring to fig. 5, a converging lens (also referred to as a receiving lens) 403 converges pulsed

laser light

404a and 404b reflected by a target from two laser beams 204a and 204b of the laser transmitter 200 onto two

pixels

402b and 402a, respectively.

The converging lens 403 is fixed to a receiving structure (not shown). The position of the converging lens 403 is unchanged, and the calibration of the optical axis of the APD photodetector of the receiving unit 400 and the optical axis of the laser emitting unit 200 is realized by adjusting the positions of the APD photodetector 401 with respect to the three dimensions of the converging lens 403.

When the central connecting line of the two

pixels

402a and 402b of the APD photodetector has an angle with the horizontal direction of the machine, the central connecting line of the two

laser output channels

202a and 202b of the laser emission unit 200 also has an angle with the horizontal direction of the machine, and the angle should be the same as the angle between the central connecting line of the two

pixels

402a and 402b of the APD photodetector and the horizontal direction of the machine.

The control unit 500 may calculate distance information and intensity information of the target in real time and read angle information of the prism and the galvanometer of the scanning unit 300 in real time.

Two

laser output channels

202a and 202b of laser transmitting unit 200 of laser radar system 100 correspond one-to-one to two

picture elements

402a and 402b of receiving unit 400.

Fig. 6 is a schematic diagram of laser emission of the lidar system in this embodiment. In fig. 6, two laser beams 204a and 204b emitted from the laser emitting unit 200 of the laser radar system 100 are linearly arranged in the vertical direction.

Fig. 7 is a schematic diagram of a scanning track of the lidar system in this embodiment. As shown in fig. 7, two laser beams emitted by the laser emission unit 200 of the laser radar system 100 are a beam 204a and a beam 204b, respectively, a beam angle α between the two laser beams 204a and 204b is fixed, a spot 207 of the beam 204b scans along the horizontal direction to form a beam trajectory 208, and a spot 207 of the beam 204a scans along the horizontal direction to form a beam trajectory 209;

in fig. 7, the beam angle α is larger than the scan angle β in the vertical direction. Since the beam angle α is larger than the scan angle β in the vertical direction, the vertical resolution at the top and bottom of the trace plot formed by the scan in fig. 7 will be lower than the vertical resolution in the middle. The scanning included angle β is an included angle between two adjacent lines scanned by the galvanometer, and is also an included angle between two adjacent light beams scanned by one laser beam, for example, 204 a.

In the foregoing embodiments of the laser radar system, the laser radar system 100 may send an instruction through the upper computer to switch the multiple operating modes in real time, so as to implement dynamic real-time adjustment of the horizontal field angle, the vertical field angle, the horizontal resolution, the vertical resolution, and the refresh frame rate.

In addition, in the scanning unit 300, since a scanning manner of a prism and a galvanometer combination is adopted, and the laser emitting unit 200 and the receiving unit 400 both emit and receive the pulse laser through the scanning unit 300, high-density point cloud display of the target can be realized with fewer light emitting sources and photodetectors.

Furthermore, the laser transmitter 200, the receiver 400 and the controller 500 may be fixed on the platform or the bracket, and only the prism and the galvanometer may rotate relative to the platform or the bracket, so that the service life and reliability of the whole laser radar system 100 are greatly improved.

The embodiment of the present application further provides a calibration method of a laser radar system, which can be applied to the laser radar system described in any of the foregoing embodiments, and the calibration method may include:

rotating the light source together with the collimator, and adjusting the position of a light beam output by the collimator and incident on the scanning unit; and/or the presence of a gas in the gas,

the positions of more than two pixels relative to the converging lens are adjusted, or more than two pixels and the converging lens rotate or move together, so that the light beams emitted after being scanned by the scanning unit are reflected by the target and then are accurately received by the receiving unit.

The calibration method of this embodiment may be applied to the system embodiment shown in fig. 1, and the implementation principle and the technical effect are similar, which are not described herein again.

In order to improve the vertical resolution of the laser radar system, in one embodiment, a beam angle is formed between different beams output by the collimator in the vertical direction, and the beam angle is greater than 0.5 degrees and less than 5 degrees; the calibration method may further include: and adjusting the scanning included angle of the scanning unit in the vertical direction so as to enable the scanning included angle to be smaller than the minimum light beam included angle in the light beam included angles. The light beams output by the collimator are provided with fixed included angles, the included angles among different light beams are enabled to be in the vertical direction by adjusting the rotation direction of the collimator along the optical axis, and the collimator is fixed by a clamping piece of the collimator after being adjusted.

It should be noted that, in the present specification, all the embodiments are described in a related manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A lidar system, comprising: the laser scanning device comprises a laser emitting unit, a scanning unit, a receiving unit and a control unit, wherein the control unit controls the laser emitting unit to emit laser, and the laser is emitted after being scanned by the scanning unit so as to be received by the receiving unit after being reflected by a target; wherein,

the laser emission unit comprises a light source and a collimator positioned on a light emergent path of the light source, the light source is provided with more than two laser output channels, and laser beams output by different laser output channels are output in a divergent mode after being collimated by the collimator; and/or the presence of a gas in the gas,

the receiving unit comprises a photoelectric detector, the photoelectric detector is provided with more than two pixels, and a converging lens is arranged on the light receiving path of the more than two pixels, so that the more than two pixels receive light reflected by the target through the converging lens.

2. The lidar system of claim 1, wherein the light source and the collimator are coupled together and rotatable together to align optical axes of the laser emitting unit and the receiving unit.

3. Lidar system according to claim 1 or 2, wherein the photodetector is movable and/or rotatable relative to the converging lens for aligning the optical axes of the laser emitting unit and the receiving unit.

4. The lidar system of claim 1 or 2, wherein the photodetector and the converging lens are movable and/or rotatable together to calibrate the optical axes of the laser transmitting unit and the receiving unit.

5. The lidar system of claim 1, wherein the laser emitted by the light source is a pulsed laser;

the outlets of the more than two laser output channels are linearly arranged in the vertical direction.

6. The lidar system of claim 5, wherein the different beams output by the collimator have beam angles in a vertical direction; and the scanning included angle of the scanning unit in the vertical direction is smaller than the minimum included angle in the light beam included angles.

7. The lidar system of claim 6, wherein an included scanning angle of the scanning unit in a vertical direction is adjustable.

8. The lidar system of claim 1, wherein the number of pixels is the same as the number of laser output channels, and wherein the two or more pixels correspond one-to-one to the two or more laser output channels.

9. A calibration method for a lidar system according to any of claims 1 to 8, comprising:

10. The method of claim 9, wherein the different beams output by the collimator have an included beam angle in a vertical direction;

the calibration method further comprises: and adjusting the scanning included angle of the scanning unit in the vertical direction so as to enable the scanning included angle to be smaller than the minimum included angle in the light beam included angles.