阅读说明：本技术 一种激光雷达扫描装置以及激光雷达扫描方法 (Laser radar scanning device and laser radar scanning method ) 是由 魏巍 黄嘉健 冉晟垚 于 2021-09-07 设计创作，主要内容包括：本发明公开了一种激光雷达扫描装置以及激光雷达扫描方法,本发明通过控制第一激光发射器发射第一激光并控制第一振镜转动以使第一激光沿着目标对象的横向进行扫描,以及控制第二激光发射器发射第二激光并控制第二振镜转动以使第二激光沿着目标对象的纵向进行扫描,使得第一激光和第二激光分别沿着目标对象在不同方向上扫描,提高扫描过程中对目标对象的覆盖度；确定发射第一激光至第一激光接收模块接收第一激光的第一飞行时间以及发射第二激光至第二激光接收模块接收第二激光的第二飞行时间,确定第一激光点的第一位置以及第二激光点的第二位置,生成目标对象的深度图像,丰富了深度图像的细节,本发明可广泛应用于激光雷达领域。(The invention discloses a laser radar scanning device and a laser radar scanning method.A first laser emitter is controlled to emit first laser and a first vibrating mirror is controlled to rotate so that the first laser scans along the transverse direction of a target object, and a second laser emitter is controlled to emit second laser and a second vibrating mirror is controlled to rotate so that the second laser scans along the longitudinal direction of the target object, so that the first laser and the second laser respectively scan along the target object in different directions, and the coverage of the target object in the scanning process is improved; the method comprises the steps of determining first flight time of transmitting first laser to a first laser receiving module to receive the first laser and second flight time of transmitting second laser to a second laser receiving module to receive the second laser, determining a first position of a first laser point and a second position of a second laser point, and generating a depth image of a target object, wherein details of the depth image are enriched.)

1. A lidar scanning apparatus, comprising:

the first laser radar system comprises a first laser transmitter, a first galvanometer and a first laser receiving module;

the second laser radar system comprises a second laser transmitter, a second galvanometer and a second laser receiving module;

the processing module comprises a control unit and a processing unit;

the control unit is used for controlling the first laser emitter to emit first laser and controlling the first galvanometer to rotate so that the first laser scans along the transverse direction of a target object, and controlling the second laser emitter to emit second laser and controlling the second galvanometer to rotate so that the second laser scans along the longitudinal direction of the target object; the first laser emits a plurality of first laser points on the target object, and the second laser emits a plurality of second laser points on the target object;

the processing unit is configured to determine a first flight time for transmitting the first laser to the first laser receiving module to receive the first laser and a second flight time for transmitting the second laser to the second laser receiving module to receive the second laser, determine a first position of the first laser spot and a second position of the second laser spot according to the first flight time and the second flight time, and generate a depth image of the target object according to the first position and the second position.

2. The lidar scanning device of claim 1, wherein: the first laser receiving module comprises a first receiving lens and a first photoelectric receiving diode, the first photoelectric receiving diode is electrically connected with the processing module, the first photoelectric receiving diode is arranged behind the first receiving lens, and the first laser is received by the first photoelectric receiving diode through the first receiving lens.

3. A lidar scanning method comprising:

controlling a first laser emitter to emit first laser and a first galvanometer to rotate so that the first laser scans along the transverse direction of a target object, and controlling a second laser emitter to emit second laser and a second galvanometer to rotate so that the second laser scans along the longitudinal direction of the target object; the first laser emits a plurality of first laser points on the target object, and the second laser emits a plurality of second laser points on the target object;

determining a first flight time from the emission of the first laser to the reception of the first laser by a first laser receiving module and a second flight time from the emission of the second laser to the reception of the second laser by a second laser receiving module;

determining a first position of the first laser spot and a second position of the second laser spot according to the first flight time and the second flight time;

and generating a depth image of the target object according to the first position and the second position.

4. The lidar scanning method of claim 3, wherein: the controlling the first laser emitter to emit first laser and the first galvanometer to rotate so that the first laser scans along the transverse direction of the target object comprises the following steps:

controlling a first laser emitter to emit first laser through a first pulse signal and controlling a first galvanometer to rotate through a first triangular wave signal so that the first laser scans along the transverse direction of a target object; the frequency of the first triangular wave signal is used for controlling the rotation frequency of the first vibrating mirror, and the amplitude of the first triangular wave signal is used for controlling the rotation amplitude of the first vibrating mirror.

5. The lidar scanning method of claim 3, wherein: the controlling the first galvanometer to rotate to enable the first laser to scan along the transverse direction of the target object, and controlling the second galvanometer to rotate to enable the second laser to scan along the longitudinal direction of the target object comprises:

controlling the first galvanometer to rotate so that the first laser light scans along a first path along a target object in a transverse first forward direction, and controlling the second galvanometer to rotate so that the second laser light scans along a second path along a target object in a longitudinal second forward direction, so as to complete the first scanning;

controlling the first galvanometer to rotate so that the first laser light scans along a third path in a repeated or non-repeated manner along a first reverse direction of the target object in the transverse direction, and controlling the second galvanometer to rotate so that the second laser light scans along a fourth path in a repeated or non-repeated manner along a second reverse direction of the target object in the longitudinal direction to complete a second scanning; the first path and the third path are staggered and form the same angle, the second path and the fourth path are staggered and form the same angle, and the first laser point and the second laser point are formed in the first scanning process and the second scanning process.

6. Lidar scanning method according to any of claims 3 to 5, wherein: first galvanometer includes first cross axle and first axis of ordinates, the second galvanometer includes second cross axle and second axis of ordinates, control first galvanometer and control second galvanometer and rotate, include:

controlling the first transverse axis to rotate at a first frequency and the first longitudinal axis to rotate at a second frequency, and controlling the second transverse axis to rotate at the second frequency and the second longitudinal axis to rotate at the first frequency; the first frequency is greater than the second frequency.

7. Lidar scanning method according to any of claims 3 to 5, wherein: the determining a first flight time from the emitting of the first laser to the receiving of the first laser by the first laser receiving module and a second flight time from the emitting of the second laser to the receiving of the second laser by the second laser receiving module includes:

and calculating first flight time of transmitting the first laser to a first laser receiving module to receive the first laser and second flight time of transmitting the second laser to a second laser receiving module to receive the second laser through a time-to-digital converter unit.

8. Lidar scanning method according to any of claims 3 to 5, wherein: determining a first position of the first laser spot and a second position of the second laser spot based on the first time of flight and the second time of flight, comprising:

acquiring the azimuth angle and the elevation angle of each first laser point and each second laser point;

calculating first distance information of each first laser point according to each first flight time and the light velocity, and calculating a three-dimensional coordinate of each first laser point as the first position according to the first distance information, the azimuth angle and the elevation angle of the first laser point;

and calculating second distance information of each second laser point according to each second flight time and the light velocity, and calculating a three-dimensional coordinate of each second laser point as the second position according to the second distance information, the azimuth angle and the elevation angle of the second laser point.

Technical Field

The invention relates to the field of laser radars, in particular to a laser radar scanning device and a laser radar scanning method.

Background

The laser radar is one of the most important sensors in application products such as unmanned vehicles, unmanned planes and intelligent robots, the maximum scanning angle and the ranging precision of the laser radar are important parameters for reflecting the safety degree of the application products, and particularly in urban environments, a high-precision laser radar system is particularly important. The lidar technology is to collect original point cloud data by using a lidar device and reversely establish a model capable of truly reflecting the appearance and the internal structure of a target object, however, the scanning mode of the lidar capable of realizing two-dimensional scanning and depth point cloud image establishment at present cannot completely cover the area in a field of view, effective two-dimensional point cloud information is difficult to extract for some target objects with extreme length and width, and the details of a depth image restored by the lidar are not rich enough and the resolution is low, so that a solution is required to be found.

Disclosure of Invention

In view of the above, in order to solve the above technical problems, an object of the present invention is to provide a laser radar scanning apparatus and a laser radar scanning method that improve coverage and resolution.

The technical scheme adopted by the invention is as follows:

a lidar scanning apparatus comprising:

the first laser radar system comprises a first laser transmitter, a first galvanometer and a first laser receiving module;

the second laser radar system comprises a second laser transmitter, a second galvanometer and a second laser receiving module;

the processing module comprises a control unit and a processing unit;

the control unit is used for controlling the first laser emitter to emit first laser and controlling the first galvanometer to rotate so that the first laser scans along the transverse direction of a target object, and controlling the second laser emitter to emit second laser and controlling the second galvanometer to rotate so that the second laser scans along the longitudinal direction of the target object; the first laser emits a plurality of first laser points on the target object, and the second laser emits a plurality of second laser points on the target object;

the processing unit is configured to determine a first flight time for transmitting the first laser to the first laser receiving module to receive the first laser and a second flight time for transmitting the second laser to the second laser receiving module to receive the second laser, determine a first position of the first laser spot and a second position of the second laser spot according to the first flight time and the second flight time, and generate a depth image of the target object according to the first position and the second position.

Further, the first laser receiving module comprises a first receiving lens and a first photoelectric receiving diode, the first photoelectric receiving diode is electrically connected with the processing module, the first photoelectric receiving diode is arranged behind the first receiving lens, and the first laser is received by the first photoelectric receiving diode through the first receiving lens.

A laser radar scanning method, comprising:

controlling a first laser emitter to emit first laser and a first galvanometer to rotate so that the first laser scans along the transverse direction of a target object, and controlling a second laser emitter to emit second laser and a second galvanometer to rotate so that the second laser scans along the longitudinal direction of the target object; the first laser emits a plurality of first laser points on the target object, and the second laser emits a plurality of second laser points on the target object;

determining a first flight time from the emission of the first laser to the reception of the first laser by a first laser receiving module and a second flight time from the emission of the second laser to the reception of the second laser by a second laser receiving module;

determining a first position of the first laser spot and a second position of the second laser spot according to the first flight time and the second flight time;

and generating a depth image of the target object according to the first position and the second position.

Further, the controlling the first laser emitter to emit the first laser and the first galvanometer to rotate so that the first laser scans along the transverse direction of the target object includes:

controlling a first laser emitter to emit first laser through a first pulse signal and controlling a first galvanometer to rotate through a first triangular wave signal so that the first laser scans along the transverse direction of a target object; the frequency of the first triangular wave signal is used for controlling the rotation frequency of the first vibrating mirror, and the amplitude of the first triangular wave signal is used for controlling the rotation amplitude of the first vibrating mirror.

Further, the controlling the first galvanometer to rotate to enable the first laser to scan along the transverse direction of the target object, and controlling the second galvanometer to rotate to enable the second laser to scan along the longitudinal direction of the target object includes:

controlling the first galvanometer to rotate so that the first laser light scans along a first path along a target object in a transverse first forward direction, and controlling the second galvanometer to rotate so that the second laser light scans along a second path along a target object in a longitudinal second forward direction, so as to complete the first scanning;

controlling the first galvanometer to rotate so that the first laser light scans along a third path in a repeated or non-repeated manner along a first reverse direction of the target object in the transverse direction, and controlling the second galvanometer to rotate so that the second laser light scans along a fourth path in a repeated or non-repeated manner along a second reverse direction of the target object in the longitudinal direction to complete a second scanning; the first path and the third path are staggered and form the same angle, the second path and the fourth path are staggered and form the same angle, and the first laser point and the second laser point are formed in the first scanning process and the second scanning process.

Further, the first galvanometer includes a first transverse axis and a first longitudinal axis, the second galvanometer includes a second transverse axis and a second longitudinal axis, the controlling of the first galvanometer rotation and the controlling of the second galvanometer rotation include:

controlling the first transverse axis to rotate at a first frequency and the first longitudinal axis to rotate at a second frequency, and controlling the second transverse axis to rotate at the second frequency and the second longitudinal axis to rotate at the first frequency; the first frequency is greater than the second frequency.

Further, the determining a first flight time from the transmitting of the first laser to the receiving of the first laser by the first laser receiving module and a second flight time from the transmitting of the second laser to the receiving of the second laser by the second laser receiving module includes:

and calculating first flight time of transmitting the first laser to a first laser receiving module to receive the first laser and second flight time of transmitting the second laser to a second laser receiving module to receive the second laser through a time-to-digital converter unit.

Further, the determining a first position of the first laser spot and a second position of the second laser spot according to the first time of flight and the second time of flight comprises:

acquiring the azimuth angle and the elevation angle of each first laser point and each second laser point;

calculating first distance information of each first laser point according to each first flight time and the light velocity, and calculating a three-dimensional coordinate of each first laser point as the first position according to the first distance information, the azimuth angle and the elevation angle of the first laser point;

and calculating second distance information of each second laser point according to each second flight time and the light velocity, and calculating a three-dimensional coordinate of each second laser point as the second position according to the second distance information, the azimuth angle and the elevation angle of the second laser point.

The invention has the beneficial effects that: the first laser emitter is controlled to emit first laser and the first galvanometer is controlled to rotate so that the first laser scans along the transverse direction of a target object, the second laser emitter is controlled to emit second laser and the second galvanometer is controlled to rotate so that the second laser scans along the longitudinal direction of the target object, the first laser and the second laser respectively scan along the target object in different directions by controlling the rotation of the different first galvanometer and the second galvanometer, so that the first laser points and the second laser points have certain number and density, and the coverage degree of the target object in the scanning process is improved; determining a first flight time of transmitting first laser to a first laser receiving module to receive the first laser and a second flight time of transmitting second laser to a second laser receiving module to receive the second laser; and determining the first position of the first laser point and the second position of the second laser point according to the first flight time and the second flight time to generate a depth image of the target object, so that the details of the finally generated depth image are enriched, and the resolution is improved.

Drawings

Fig. 1 is a schematic perspective view of a lidar scanning apparatus according to an embodiment of the present invention;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a schematic flow chart illustrating steps of a laser radar scanning method according to the present invention;

fig. 4(a) is a schematic diagram of a repetitive mode scan according to an embodiment of the present invention, fig. 4(b) is a schematic diagram of a non-repetitive mode scan according to an embodiment of the present invention, fig. 4(c) is a schematic diagram of a first scan according to an embodiment of the present invention, and fig. 4(d) is a schematic diagram of a second scan according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a lidar system according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of the positions of laser spots according to an embodiment of the present invention.

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but 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 application.

The terms "first," "second," "third," and "fourth," etc. in the description and claims of this application and in the accompanying drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

As shown in fig. 1 and 2, an embodiment of the present invention provides a lidar scanning apparatus including a first lidar system 100, a second lidar system 200, and a processing module (not shown).

As shown in fig. 1 and 2, optionally, first laser radar system 100 includes a first laser transmitter 11, a first galvanometer 12, and a first laser receiving module. In the embodiment of the present invention, the first laser receiving module includes a first receiving lens 13 and a first photo receiving diode 14, the first photo receiving diode 14 is electrically connected to the processing module, the first photo receiving diode 14 is disposed behind the first receiving lens 13, and the first laser is received by the first photo receiving diode 14 through the first receiving lens 13. Optionally, the first galvanometer 12 includes a first transverse axis X1 and a first longitudinal axis Y1, the first transverse axis X1 and the first longitudinal axis Y1 have corresponding control mirrors, and the processing module controls rotation of the first transverse axis X1 and the first longitudinal axis Y1 to enable rotation of the first galvanometer 12.

As shown in fig. 1 and 2, optionally, the second laser radar system 200 includes a second laser transmitter 21, a second galvanometer 22, and a second laser receiving module. In the embodiment of the present invention, the second laser receiving module includes a second receiving lens 23 and a second photo receiving diode 24, the second photo receiving diode 24 is electrically connected to the processing module, the second photo receiving diode 24 is disposed behind the second receiving lens 23, and the second laser is received by the second photo receiving diode 24 through the second receiving lens 23. Optionally, the second galvanometer 22 includes a second transverse axis X2 and a second longitudinal axis Y2, the second transverse axis X2 and the second longitudinal axis Y2 have corresponding control mirrors, and the processing module controls rotation of the second transverse axis X2 and the second longitudinal axis Y2 to enable rotation of the second galvanometer 22. The first galvanometer mirror 12 and the second galvanometer mirror 22 include, but are not limited to, galvanometer mirrors or MEMS mirrors.

As shown in fig. 1 and 2, it should be noted that the first galvanometer 12 and the second galvanometer 22 are used for controlling the path of laser scanning; the first laser emitter 11 and the second laser emitter 21 include a laser emitter driving function, and are both configured with a collimating lens, and the collimating lens can make the light spot smaller than the lens. The first laser receiving module and the second laser receiving module may include an echo amplifying circuit; the first receiving lens 13 and the second receiving lens 23 are large-area optical special convex lenses, and are used for focusing the echo signals, that is, focusing the laser light reflected from the target object, so that the laser light hits the first photo receiving diode 14 or the second photo receiving diode 24 and is absorbed.

Optionally, in this embodiment of the present invention, the processing module includes a control unit and a processing unit.

Specifically, the control unit is configured to control the first laser emitter 11 to emit the first laser and control the first galvanometer 12 to rotate so that the first laser scans along the transverse direction of the target object, and control the second laser emitter 21 to emit the second laser and control the second galvanometer 22 to rotate so that the second laser scans along the longitudinal direction of the target object. It should be noted that, during the scanning process, the first laser emits a plurality of first laser points on the target object, and the second laser emits a plurality of second laser points on the target object.

Specifically, the processing unit is configured to determine a first flight time for transmitting the first laser to the first laser receiving module to receive the first laser and a second flight time for transmitting the second laser to the second laser receiving module to receive the second laser, determine a first position of the first laser spot and a second position of the second laser spot according to the first flight time and the second flight time, and generate the depth image of the target object according to the first position and the second position.

The first laser radar system and the second laser radar system in the embodiment of the present invention are not limited to the left-right distribution structure, and may be a top-bottom distribution structure. It should be noted that, the processing module in the embodiment of the present invention includes, but is not limited to, an FPGA main controller, and controls the first laser emitter 11 and the second laser emitter 21 to emit laser light through the generated pulse signal; generating a triangular wave signal to drive the first galvanometer 12 and the second galvanometer 22 to rotate; a first time of flight and a second time of flight are determined by a time-to-digital converter unit (TDC) in the processing unit, and then a first position and a second position are determined. It should be noted that the generating of the depth image of the target object according to the first position and the second position may be to transmit the point cloud data including the first position and the second position to the upper computer to generate the depth image of the target object, that is, the processing module includes the FPGA main controller and a part of the upper computer at this time. Optionally, the time-to-digital converter unit is a dual-channel time-to-digital converter, which may be built in the FPGA main controller or may also be a TDC-GP2X timing chip, and is not specifically limited, and may be used to implement high-precision time of flight technology tof (time of flight) timing of the first laser radar system 100 and the second laser radar system 200, and store a timing result in a digital register of the FPGA main controller with 8 bits, and the TDC implemented based on the FPGA has functions of a basic coarse-coarse time counter, delay calibration, temperature compensation, and the like.

As shown in fig. 3, an embodiment of the present invention provides a laser radar scanning method, which can be applied to the laser radar scanning apparatus, and includes steps S100 to S400:

s100, controlling a first laser emitter to emit first laser and a first galvanometer to rotate so that the first laser scans along the transverse direction of the target object, and controlling a second laser emitter to emit second laser and a second galvanometer to rotate so that the second laser scans along the longitudinal direction of the target object.

In the embodiment of the invention, in the scanning process, the first laser emits a plurality of first laser points on the target object, and the second laser emits a plurality of second laser points on the target object.

It should be noted that the frequency of laser emission and the frequency of oscillating mirror swing affect the point cloud data contained in each image, and the amplitude of oscillating mirror swing affects the maximum scanning angle, so that the internal program of the FPGA can be adjusted according to the actual situation, and the frequency of laser emission and the frequency and amplitude of oscillating mirror rotation (oscillation) are adjusted to obtain the point cloud data meeting the actual requirements.

In the embodiment of the invention, the processing module controls the first laser emitter to emit the first laser through the first pulse signal and controls the first galvanometer to rotate through the first triangular wave signal so that the first laser scans along the transverse direction of the target object, and controls the second laser emitter to emit the second laser through the second pulse signal and controls the second galvanometer to rotate through the second triangular wave signal so that the second laser scans along the longitudinal direction of the target object. Optionally, the first pulse signal and the second pulse signal are narrow trigger pulse signals of 24khz, 50 ns. The first triangular wave signal includes two triangular wave signals respectively driving the first horizontal axis X1 and the first vertical axis Y1, and the second triangular wave signal also includes two triangular wave signals respectively driving the second horizontal axis X2 and the second vertical axis Y2. The frequency of the first triangular wave signal is used for controlling the rotation frequency of the first galvanometer, specifically the rotation frequency of a first horizontal axis X1 and a first vertical axis Y1, and the frequency of the second triangular wave signal is used for controlling the rotation frequency of the second galvanometer, specifically the rotation frequency of a second horizontal axis X2 and a second vertical axis Y2; the amplitude of the first triangular wave signal is used for controlling the rotation amplitude of the first galvanometer, specifically the rotation amplitude of the first horizontal axis X1 and the first vertical axis Y1, and the amplitude of the second triangular wave signal is used for controlling the rotation amplitude of the second galvanometer, specifically the rotation amplitude of the second horizontal axis X2 and the second vertical axis Y2. It should be noted that, when a higher imaging speed is required, the rotation frequency of the galvanometer may be adjusted in real time, for example, the adjustment procedure may make the frequency of the driving triangular wave signal larger, and for a target object with a larger width, the rotation amplitude of the transverse axis of the galvanometer may be adjusted in real time, for example, the adjustment procedure may make the driving triangular wave signal have a larger amplitude.

In the embodiment of the invention, the driving signal of the triangular wave is used, and the angle of the triangular wave is linearly changed to achieve the consistency of the front scanning angle and the rear scanning angle, so that the scanning angle of the second scanning can be consistent with the first scanning angle when the first scanning and the second scanning are carried out subsequently, the scanning paths are not overlapped but staggered, and the number and the density of the obtained laser points are increased. In addition, when a square wave is used, the oscillating change of the galvanometer is not uniform, and when a sawtooth wave is used, the front and rear scanning angles are not uniform.

Optionally, in this embodiment of the present invention, the first horizontal axis is controlled to rotate at the first frequency and the first vertical axis is controlled to rotate at the second frequency, and the second horizontal axis is controlled to rotate at the second frequency and the second vertical axis is controlled to rotate at the first frequency; the first frequency is (much) greater than the second frequency. It is understood that the first frequency and the second frequency are frequencies of triangular wave signals. For example, in the case that the frame rate is 10fps and each frame is scanned once, the frequency of the first horizontal axis rotation is 340Hz, and the frequency of the first vertical axis rotation is 10Hz, then correspondingly, the frequency of the second horizontal axis rotation is 10Hz, and the frequency of the second vertical axis rotation is 340 Hz.

In the embodiment of the present invention, in step S100, controlling the first galvanometer to rotate to enable the first laser to scan along the transverse direction of the target object, and controlling the second galvanometer to rotate to enable the second laser to scan along the longitudinal direction of the target object, includes steps S110 to S120:

s110, controlling the first galvanometer to rotate so that the first laser scans along a first path in a first transverse positive direction along the target object, and controlling the second galvanometer to rotate so that the second laser scans along a second path in a second longitudinal positive direction along the target object, so as to complete the first scanning.

S120, controlling the first galvanometer to rotate so that the first laser light scans along the third path in a repeated mode or a non-repeated mode along the first transverse reverse direction of the target object, and controlling the second galvanometer to rotate so that the second laser light scans along the fourth path in a repeated mode or a non-repeated mode along the second longitudinal reverse direction of the target object to complete second scanning; the first path and the third path are staggered and form the same angle, the second path and the fourth path are staggered and form the same angle, and the first laser point and the second laser point are formed in the processes of first scanning and second scanning.

It should be noted that the scanning principle of the repetitive mode is shown in fig. 4(a), the repetitive mode refers to that the scanning path of the laser radar system repeats and becomes an image after reaching one frame, while the scanning principle of the non-repetitive mode is shown in fig. 4(b), and refers to that the scanning path does not repeat into an image after the laser radar system scans for two or more frames, the arrow indicates the direction of the scanning path, X indicates the lateral direction, and Y indicates the longitudinal direction. In the embodiment of the present invention, a non-repeating manner is taken as an example, that is, a path of the second scanning and a path of the first scanning are not repeated, that is, the first path and the third path, and the second path and the fourth path are staggered. It will be appreciated that when scanned in a repetitive manner, the third path at least partially overlaps (or is identical to) the first path and the fourth path at least partially overlaps (or is identical to) the second path.

Specifically, as shown in fig. 4(c), during the first scan, the first path extends in a first positive direction in the transverse direction (scanning in the left-right direction and from bottom to top in the longitudinal direction), starting with path L11 and ending with path L12, and the second path extends in a second positive direction in the longitudinal direction (scanning in the longitudinal direction and from left to right in the transverse direction), starting with path L21 and ending with path L22. As shown in fig. 4(d), on the basis of the first scanning, a second scanning is performed, and during the second scanning, the third path extends in a first reverse direction in the transverse direction (the first reverse direction is scanned in the left-right direction with respect to the first forward direction, and specifically is scanned in the left-right direction and is from top to bottom in the longitudinal direction), starts with the path L31 and ends with the path L32, and the fourth path extends in a second reverse direction in the longitudinal direction (the second reverse direction is scanned in the longitudinal direction with respect to the second forward direction, and is scanned in the transverse direction from right to left), starts with the path L41 and ends with the path L42, so as to implement the scanning of the target object M, ensure the scanning of the target object M, and improve the integrity of the scanning process. It should be noted that the first laser point exists in the first path and the third path, the second laser point exists in the second path and the fourth path, and it can be seen that the first path and the third path are staggered, parallel and at the same angle, that is, the angle between the sub-paths included in the first path is the same as the angle between the sub-paths of the third path, and the second path and the fourth path are staggered, parallel and at the same angle, that is, the angle between the sub-paths included in the second path is the same as the angle between the sub-paths included in the fourth path.

As shown in fig. 5, in the embodiment of the present invention, during the first scanning and the second scanning, the first lidar system (group) starts to operate, the second lidar system (group) is in a static state, when the first lidar system emits a single photon (first laser) and is received by the first laser receiving module, the first lidar system (group) shifts to the static state, and the second lidar system (group) shifts to an operating state, which is similar to the case where the second lidar system completes the transmission and reception of the single photon (second laser)), the first lidar system (group) shifts to the operating state, and so on, the processes of the first scanning and the second scanning can be completed.

S200, determining a first flight time of transmitting the first laser to the first laser receiving module to receive the first laser and a second flight time of transmitting the second laser to the second laser receiving module to receive the second laser.

In the embodiment of the present invention, the first flight time refers to an elapsed time from when the first laser emitter emits the first laser to reach the target object and reflect to the first laser receiving module for receiving (specifically, receiving by the first photo receiving diode); the second time of flight refers to the time that the second laser transmitter transmits the second laser light to reach the target object and is reflected to the second laser receiving module to be received (specifically, received by the second photodiode). Specifically, the first time of flight and the second time of flight are calculated by a time-to-digital converter unit (TDC).

S300, determining a first position of the first laser spot and a second position of the second laser spot according to the first flight time and the second flight time.

Specifically, step S300 includes steps S310-S330:

s310, acquiring the azimuth angle and the elevation angle of each first laser point and each second laser point.

S320, calculating first distance information of each first laser point according to each first flight time and the light speed, and calculating a three-dimensional coordinate of each first laser point as a first position according to the first distance information, the azimuth angle and the elevation angle of the first laser point.

S330, calculating second distance information of each second laser point according to each second flight time and the light speed, and calculating a three-dimensional coordinate of each second laser point as a second position according to the second distance information, the azimuth angle and the elevation angle of the second laser point.

Specifically, as shown in fig. 6, assume that there is a laser point P on the target object, where P has an azimuth angle α and an elevation angle β, X from the origin of coordinates₁、Y₁、Z₁Respectively represents three coordinate axes, and the calculation formula is as follows:

X₂＝d sinαcosβ

Y₂＝d sinαsinβ

Z₂＝d cosα

where d is distance information, v is the speed of light, t is the time of flight, X₂、Y₂、Z₂Respectively, an abscissa, an ordinate and a vertical coordinate in the three-dimensional coordinate. It can be understood that when the laser point P is the first laser point, the flight time is the first flight time, and the coordinate is originalThe point is the position of the first laser emitter, and the distance information obtained by calculation by using the formula is the first distance information and the first position of the first laser point; when the laser point P is a second laser point, the flight time is a second flight time, the origin of coordinates is the position of the second laser emitter, and the distance information calculated by the formula is the second distance information and the second position of the second laser point.

It should be noted that the above calculation process may be completed by an FPGA, where the azimuth angle α and the elevation angle β may be determined according to the rotation frequency of the horizontal axis and the vertical axis, a CORDIC algorithm is adopted inside the FPGA to implement the operation of a trigonometric function, or a MATLAB generates a sine value and a cosine value corresponding to the azimuth angle α and the elevation angle β angle of each laser point and stores the values in two mif files, the files are stored in a ROM of the FPGA, and then a specific step length is set according to the rotation frequency of the horizontal axis and the vertical axis to extract an effective value therefrom.

And S400, generating a depth image of the target object according to the first position and the second position.

In the embodiment of the invention, each first position and each second position represent a depth point to form a part of a point cloud, the first positions and the second positions are stored in an upper computer, the upper computer stores the first positions and the second positions, and all the depth points represented by the first positions and the second positions are synthesized to obtain a high-resolution depth image of a target object.

According to the laser radar scanning method and the laser radar scanning device, the scanning mode that the first vibrating mirror and the second vibrating mirror are used for sharing two groups of vibrating mirrors is adopted, the target object of a scanning field of view can be scanned from different directions and angles, the scanning field of view is expanded, the two-channel high-precision time-to-digital converter is realized through the FPGA, the high-precision high-density point cloud information extraction of the laser radar system based on the vibrating mirror scanning is realized, so that the depth image of the surface of the target object with richer details can be extracted, the coverage of the target object in the scanning process is improved, the working efficiency of the laser radar system is improved, the details of the finally generated depth image are enriched, the resolution is improved, and the high-precision distance measurement and timing can be realized by adopting the two-channel high-precision time-to-digital converter

It should be understood that in the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" for describing an association relationship of associated objects, indicating that there may be three relationships, e.g., "a and/or B" may indicate: only A, only B and both A and B are present, wherein A and B may be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single item(s) or plural items. For example, at least one (one) of a, b, or c, may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, a division of a unit is merely a logical division, and an actual implementation may have another division, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form. Units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment. In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.