Lidar system, control method and control apparatus

Abstract

A LiDAR system, a control method and a control apparatus. The LiDAR system comprises a transmitting unit, a first scanning unit, and a first optical element arranged between the transmitting unit and the first scanning unit. The first optical element is used for adjusting the propagation direction of light beams emitted by the transmitting unit, so as to transmit the light beams emitted by the transmitting unit to the first scanning unit. The deflection effect of the first optical element on the light beams is determined on the basis of the scanning speed of the first scanning unit. The LiDAR system, control method and control apparatus can be used in detection or sensing systems of new energy vehicles or intelligent driving vehicles, can compensate for and reduce the impact of the scanning process of a scanning unit on the propagation of light beams, and can improve the speed measurement and ranging performance of a LiDAR.

Description

Laser radar system, control method and control device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on December 19, 2023, with application number 202311760922.8 and invention name “Lidar system, control method and control device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of detection technology, and more specifically, to a laser radar system, a control method, and a control device. Background Art

[0003] Lasers are widely used in detection devices, such as lidar (LiDAR). The detection light signal emitted by the LiDAR illuminates the target object and, after reflection, produces a scattered light signal. The system receives this reflected scattered light signal and, after beating it with the local oscillator light, generates an intermediate-frequency current signal. This intermediate-frequency current signal includes the target's time delay information, from which the target's distance can be inferred. Furthermore, if the target has a velocity in the direction of the laser, the return light signal will be Doppler modulated, resulting in the final intermediate-frequency signal including Doppler frequency information.

[0004] When using low-channel LiDAR, a scanning mechanism can achieve wide field-of-view imaging. However, the scanning process can lead to delays in transmission and reception, scanning decoherence, and other phenomena, which can affect the LiDAR's speed and ranging performance. Therefore, ensuring the LiDAR's speed and ranging performance when using a scanning mechanism has become a pressing issue. Summary of the Invention

[0005] The present application provides a laser radar system, a control method and a control device, which can improve the speed and distance measurement performance of the laser radar when a scanning mechanism is adopted.

[0006] In a first aspect, a laser radar system is provided. The laser radar system may include a transmitting unit, a first optical element, and a first scanning unit, wherein the first optical element is disposed between the transmitting unit and the first scanning mechanism. The transmitting unit is configured to transmit a light beam. The first scanning unit is configured to scan the light beam from the first optical element. The first optical element is configured to receive a first light beam at a first time point and emit a first detection beam; receive a second light beam at a second time point and output a second detection beam, wherein the angle between the first light beam and the first detection beam is a first angle, and the angle between the second light beam and the second detection beam is a second angle, and the angular difference between the first angle and the second angle is determined based on the scanning speed of the first scanning mechanism.

[0007] Exemplarily, the light beam emitted by the emitting unit may be a pulsed light beam, or may be a continuous wave light beam, which is not limited in the embodiments of the present application. The first time point and the second time point may be any time points. The first light beam may include the light beam emitted by the emitting unit at the first time point, or the light beam emitted by the emitting unit that reaches the first optical element at the first time point. Similarly, the second light beam may include the light beam emitted by the emitting unit at the second time point. For the first optical element, the first detection beam may be the outgoing light corresponding to the first light beam; accordingly, the first light beam may be the outgoing light corresponding to the first detection beam. Similarly, the second detection beam may be the outgoing light corresponding to the second light beam, and accordingly, the second light beam may be the incident light corresponding to the second detection beam.

[0008] Exemplarily, the first optical element is disposed between the transmitting unit and the first scanning unit, and may include: the first optical element is disposed on the propagation path of the light beam emitted by the transmitting unit. On this propagation path, the light beam first propagates to the first optical element and then to the first scanning unit. The first optical element can be used to change the propagation path of the light beam emitted by the transmitting unit. For example, the first optical element can change the propagation path of the light beam emitted by the transmitting unit, and the first steering angle and the second steering angle can be generated by the first optical element deflecting the light beam.

[0009] In the traditional solution, for low-channel laser radar, a scanning mechanism can be used to scan the light beam by changing the posture of the scanning mechanism, thereby achieving large field of view imaging. However, the scanning process will lead to phenomena such as transmission and reception delay angle and scanning decoherence, which will affect the speed and ranging performance of the laser radar. For example, taking the continuous wave laser radar in the traditional solution as an example, under the action of the scanning mechanism, in one sampling period, the detection light beam emitted by the scanning mechanism will scan the corresponding area of ​​the surface of the target object once with a preset trajectory. Accordingly, the light spot formed by the detection light beam irradiating the surface of the target object can be called a detection light spot, and the trajectory of the movement of the detection light spot can be called the scanning trajectory of the detection light spot (which can be simply referred to as the scanning trajectory).

[0010] On the one hand, in actual scenarios, the microstructure of the surface of the target object has ups and downs and is highly random. The microstructure will produce a certain degree of phase modulation on the detection light signal. When a scanning mechanism (such as a scanning mirror) is used, when the light beam emitted by the scanning mechanism is irradiated at different positions on the surface of the target object, the microstructures at different positions will produce different degrees of phase modulation, resulting in additional modulation of the spectrum of the intermediate frequency signal, which is the so-called scanning decoherence phenomenon. In traditional solutions, it is difficult to know or eliminate the phase modulation caused by the microstructure during the scanning process.

[0011] On the other hand, when the scanning mechanism scans at a high speed, the position (or posture) of the scanning mechanism will change between the time the probe beam is emitted by the scanning mechanism and the time the return light of the probe beam returns to the scanning mechanism. This makes it difficult to align the target signal at the receiving optical fiber or waveguide, which is a phenomenon called the transceiver delay angle. This transceiver delay angle significantly degrades the signal strength detected by the receiving side.

[0012] For example, in the laser radar system provided by the present application, the first angle and the second angle are generated by the deflection effect of the first optical element on the light beam, and the angular difference between the first angle and the second angle is determined according to the scanning speed of the first scanning unit. That is to say, compared with the traditional solution, in the laser radar system provided by the present application, a first optical element capable of deflecting the light beam is provided between the transmitting unit and the first scanning unit, and the deflection effect of the first optical element on the light beam is determined according to the scanning speed of the first scanning unit. When the first scanning unit is in different postures during the scanning process, by controlling the deflection effect of the first optical element on the light beam, taking a continuous wave radar as an example, the scanning trajectory of the detection light spot can be adjusted, thereby improving the speed and ranging performance of the laser radar.

[0013] In one embodiment, during a sampling cycle, the first optical element's deflection of the beam's propagation direction is controlled based on the scanning speed of the first scanning unit, enabling multiple scans of the same region on the surface of the target object. In other words, during the same scanning cycle, the region can be scanned multiple times along a preset scanning trajectory. This approach allows the phase modulation effect of the beam on the region's microstructure to be determined, thereby mitigating the impact of scanning decoherence on the performance of laser speed and ranging measurements.

[0014] In another embodiment, in a sampling period, the deflection effect of the first optical element on the propagation direction of the light beam is controlled according to the scanning speed of the first scanning unit, so that the movement distance of the detection light spot on the surface of the target object in the sampling period can be shortened, the phase modulation caused by scanning in the sampling period can be reduced, and the influence of the transmission and reception delay angle caused by scanning on the laser speed and ranging performance can be reduced.

[0015] In this application, the deflection effect of the first optical element on the propagation direction of the light beam is determined according to the scanning speed of the first scanning unit, which can compensate for and reduce the impact of the scanning process of the scanning unit on the propagation of the light beam, and can reduce the impact of the scanning unit on the speed and ranging performance of the laser radar.

[0016] In some possible implementations, the lidar system may further include a receiving unit configured to receive return light from the probe beam. For example, after the probe beam emitted by the first optical element is scanned by the scanning unit, it is reflected by the target object to generate return light from the probe beam. This return light from the probe beam can then be transmitted through the scanning unit to the receiving unit, where it is received. Furthermore, speed and distance can be measured based on the return light from the probe beam and the local oscillator light of the beam emitted by the transmitting unit.

[0017] In conjunction with the first aspect, in certain implementations of the first aspect, the first optical element can deflect the light beam through reflection. For example, the first optical element can include an optical element such as a galvanometer mirror or an oscillating mirror that deflects the light beam through reflection. For another example, by adjusting the posture of the galvanometer mirror or oscillating mirror, the deflection effect on the propagation direction of the light beam can be changed.

[0018] In combination with the first aspect, in certain implementations of the first aspect, the first steering angle is generated by reflection when the first optical element is at a first reflection angle, and the second steering angle is generated by reflection when the first optical element is at a second reflection angle, and the change in the reflection angle of the first optical element is determined according to the scanning speed of the first scanning unit.

[0019] For example, in a scenario where the first optical element achieves light beam deflection through reflection, when the position of the incident light beam remains unchanged, when the first optical element is at different reflection angles (it can also be said that the first optical element is in different postures), the position of the corresponding outgoing light beam will change, and the angle between the incident light beam and the outgoing light beam will change.

[0020] In scenarios where the first optical element deflects the light beam through reflection, the light beam deflection effect of the first optical element is associated with its posture. In this application, by determining the change in the reflection angle of the first optical element based on the scanning speed of the first scanning unit, it is possible to control the angular difference between the first and second steering angles without having to measure them in real time, thereby simplifying the control of the light beam deflection effect of the first optical element.

[0021] In combination with the first aspect, in some implementations of the first aspect, during the first sampling period, the rotation speed of the first optical element is the same as the scanning speed of the first scanning unit, and the first optical element and the first scanning unit deflect the light beam in opposite directions.

[0022] Exemplarily, the first sampling period may be any sampling period. The first sampling period may include a first time point and a second time point.

[0023] In the present application, the deflection of the light beam by the first optical element can compensate for the deflection effect of the light beam by the first scanning unit, shorten the movement distance of the detection spot on the surface of the target object during the sampling period, reduce the degradation of the signal strength on the receiving side caused by the posture change of the first scanning unit, and reduce the impact of scanning on the performance of laser speed and ranging.

[0024] In combination with the first aspect, in certain implementations of the first aspect, in the first half of the first sampling period, the rotational speed of the first optical element is zero; in the second half of the first sampling period, the rotational speed of the first optical element is twice the scanning speed of the first scanning unit, and the first optical element and the first scanning unit have opposite deflection directions of the light beam.

[0025] In the present application, within the same sampling period, the same scanning trajectory can be scanned back and forth through the deflection of the light beam by the first optical element and the scanning effect of the light beam by the first scanning unit, thereby obtaining the phase modulation result of the light beam by the microstructure, and reducing the impact of the scanning on the laser speed and ranging performance.

[0026] In conjunction with the first aspect, in certain implementations of the first aspect, the first optical element can deflect the light beam through refraction. For example, the first optical element can include a rotatable lens, a photoelectric crystal, a magnetoelectric crystal, a pyroelectric crystal, a liquid crystal, etc. For another example, by adjusting the refractive index of the photoelectric crystal, its deflection effect on the propagation direction of the light beam can be changed.

[0027] For example, the refractive index of each part of the rotatable lens can be the same. By changing the shape and / or posture of the rotatable lens, the deflection effect of the rotatable lens on the light beam can be changed.

[0028] In combination with the first aspect, in certain implementations of the first aspect, the first optical element includes a rotatable lens, the first side of the rotatable lens includes a first plane, the second side of the rotatable lens includes a first curved surface, the curvature of the first curved surface at a first position changes linearly when the rotatable lens moves along the first axis, the first position includes the exit position when the light beam exits through the first curved surface, the first axis is perpendicular to the first plane, and the angular difference between the first steering angle and the second steering angle is generated by the movement of the rotatable lens along the first axis.

[0029] For example, the first plane and the first curved surface can be arranged relative to each other along a first axis, and the light beam emitted by the emitting unit can be incident along the first plane and emitted along the first curved surface. Accordingly, when the rotatable lens rotates along the first axis, the curvature of the light beam at the exit position on the first curved surface changes along a certain direction (e.g., a first direction). For example, the curvature can change linearly along the first direction. The first direction can be the direction in which the exit position of the light beam changes when the scanning lens moves.

[0030] In combination with the first aspect, in certain implementations of the first aspect, a movement speed of the rotatable lens along the first axis is determined according to a scanning speed of the first scanning unit.

[0031] In one embodiment, a light beam emitted by the emitting unit enters the rotatable lens via a first plane and, accordingly, exits from the first curved surface. Assuming the incident light beam is parallel to the first axis, the curvature of the light beam at the exit position on the first curved surface varies linearly along a first direction. For example, when the first scanning unit scans at a uniform speed, the rotatable lens can be controlled to rotate at a uniform speed along the first axis based on the scanning speed of the first scanning unit.

[0032] In the present application, the movement speed of the rotatable lens along the first axis is determined based on the scanning speed of the first scanning unit, and the angular difference between the first steering angle and the second steering angle can be controlled without the need to measure the two in real time, which can simplify the control of the light beam deflection effect of the first optical element.

[0033] In combination with the first aspect, in some implementations of the first aspect, the first optical element includes a photoelectric crystal, a magnetoelectric crystal, a pyroelectric crystal, or a liquid crystal element, and a change in the refractive index of the first optical element is determined according to a scanning speed of the first scanning unit.

[0034] In the present application, the change in the refractive index of the first optical element is determined based on the scanning speed of the first scanning unit, and the angular difference between the first steering angle and the second steering angle can be controlled without the need to measure the two in real time, which can simplify the control of the light beam deflection effect of the first optical element.

[0035] In combination with the first aspect, in certain implementations of the first aspect, the system also includes a second scanning unit arranged between the first optical element and the first scanning unit, the second scanning unit being used to transmit the light beam emitted by the coherent light beam through the first optical element to the first scanning unit, and the scanning speed of the first scanning unit is greater than the scanning speed of the second scanning unit.

[0036] For example, a laser radar system may include multiple scanning units to enable scanning in multiple dimensions. Accordingly, the scanning speeds of the multiple scanning units may differ. For example, a laser scanning system may include a fast scanning unit and a slow scanning unit. The first scanning unit may include a fast scanning unit, and the second scanning unit may include a slow scanning unit.

[0037] In combination with the first aspect, in certain implementations of the first aspect, the light beam emitted by the emitting unit is a coherent light beam.

[0038] A second aspect provides a control method that can be executed by a LiDAR system, or by an intelligent driving device equipped with the LiDAR system, or by a chip or processor corresponding to the LiDAR system. In some possible implementations, the chip or processor corresponding to the LiDAR system can be installed within the radar or externally.

[0039] The method includes: obtaining a scanning speed of a first scanning unit; determining an angular difference between a first steering angle and a second steering angle according to the scanning speed of the first scanning unit, wherein the first steering angle includes an angle between a first light beam and a first detection light beam at a first time point, the first detection light beam being a light beam emitted by the first light beam through a first optical element; the second steering angle includes an angle between a second light beam and a second detection light beam at a second time point, the second detection light beam being a light beam emitted by the second light beam through a first optical element, the first optical element being arranged between an emitting unit and the first scanning unit, and the first light beam and the second light beam being emitted by the emitting unit.

[0040] In conjunction with the second aspect, in certain implementations of the second aspect, the first steering angle is generated by reflection when the first optical element is at the first reflection angle, and the second steering angle is generated by reflection when the first optical element is at the second reflection angle. Determining the angular difference between the first steering angle and the second steering angle based on a scanning speed of the first scanning unit may include determining a change in the reflection angle of the first optical element based on the scanning speed of the first scanning unit.

[0041] In combination with the second aspect, in certain implementations of the second aspect, the speed of change of the reflection angle of the first optical element includes the rotational speed of the first optical element. During the first sampling period, the rotational speed of the first optical element is the same as the scanning speed of the first scanning unit, and the first optical element and the first scanning unit have opposite deflection directions of the light beam.

[0042] In combination with the second aspect, in certain implementations of the second aspect, the speed of change of the reflection angle of the first optical element includes the rotational speed of the first optical element. In the first half of the first sampling period, the rotational speed of the first optical element is zero; in the second half of the first sampling period, the rotational speed of the first optical element is twice the scanning speed of the first scanning unit, and the first optical element and the first scanning unit have opposite deflection directions of the light beam.

[0043] In conjunction with the second aspect, in certain implementations of the second aspect, the first optical element includes a rotatable lens, a first side of the rotatable lens includes a first plane, a second side of the rotatable lens includes a first curved surface, a curvature of the first curved surface at a first position changes linearly when the rotatable lens moves along a first axis, the first position includes an exit position of a light beam when it exits through the first curved surface, and the first axis is perpendicular to the first plane. Determining the angular difference between the first steering angle and the second steering angle based on a scanning speed of the first scanning unit may include: determining a movement speed of the rotatable lens along the first axis based on the scanning speed of the first scanning unit.

[0044] In conjunction with the second aspect, in certain implementations of the second aspect, the first steering angle and the second steering angle are generated by refraction by the first optical element. Determining the angular difference between the first steering angle and the second steering angle based on a scanning speed of the first scanning unit may include determining a rate of change of a refractive index of the first optical element based on the scanning speed of the first unit.

[0045] In combination with the second aspect, in certain implementations of the second aspect, a second scanning unit is arranged between the first optical element and the first scanning unit, and the light beam emitted by the coherent light beam through the first optical element is transmitted to the first scanning unit through the second scanning unit, and the scanning speed of the first scanning unit is greater than the scanning speed of the second scanning unit.

[0046] In combination with the second aspect, in some implementations of the second aspect, the light beam emitted by the emission unit may include a coherent light beam.

[0047] In combination with the second aspect, in some implementations of the second aspect, the first optical element may include a galvanometer mirror, a swing mirror, a rotatable lens, a photoelectric crystal, a magnetoelectric crystal, a pyroelectric crystal, or a liquid crystal element.

[0048] In a third aspect, a control device is provided, which may include: an acquisition unit for acquiring a scanning speed of a first scanning unit; a processing unit for determining an angular difference between a first steering angle and a second steering angle based on the scanning speed of the first scanning unit, the first steering angle including an angle between a first light beam and a first detection light beam at a first time point, the first detection light beam being a light beam emitted by the first optical element, the second steering angle including an angle between a second light beam and a second detection light beam at a second time point, the second detection light beam being a light beam emitted by the second light beam through the first optical element, the first optical element being arranged between the emitting unit and the first scanning unit, the first light beam and the second light beam being emitted by the emitting unit.

[0049] In conjunction with the third aspect, in certain implementations of the third aspect, the first steering angle is generated by reflection when the first optical element is at the first reflection angle, and the second steering angle is generated by reflection when the first optical element is at the second reflection angle. The processing unit may be configured to determine a change in the reflection angle of the first optical element based on a scanning speed of the first scanning unit.

[0050] In combination with the third aspect, in certain implementations of the third aspect, the speed of change of the reflection angle of the first optical element includes the rotational speed of the first optical element. In the first half of the first sampling period, the rotational speed of the first optical element is zero; in the second half of the first sampling period, the rotational speed of the first optical element is twice the scanning speed of the first scanning unit, and the first optical element and the first scanning unit have opposite deflection directions of the light beam.

[0051] In combination with the third aspect, in certain implementations of the third aspect, the speed of change of the reflection angle of the first optical element includes the rotational speed of the first optical element. In the first half of the first sampling period, the rotational speed of the first optical element is zero; in the second half of the first sampling period, the rotational speed of the first optical element is twice the scanning speed of the first scanning unit, and the first optical element and the first scanning unit have opposite deflection directions of the light beam.

[0052] In conjunction with the third aspect, in certain implementations of the third aspect, the first optical element includes a rotatable lens, a first side of the rotatable lens includes a first plane, a second side of the rotatable lens includes a first curved surface, a curvature of the first curved surface at a first position changes linearly when the rotatable lens moves along a first axis, the first position includes an exit position of a light beam when it exits through the first curved surface, and the first axis is perpendicular to the first plane. The processing unit may be configured to determine a movement speed of the rotatable lens along the first axis based on a scanning speed of the first scanning unit.

[0053] In combination with the third aspect, in certain implementations of the third aspect, the first steering angle and the second steering angle are generated by the first optical element through refraction, and the processing unit can be used to: determine the change rate of the refractive index of the first optical element based on the scanning speed of the first unit.

[0054] In combination with the third aspect, in certain implementations of the third aspect, a second scanning unit is arranged between the first optical element and the first scanning unit, and the light beam emitted by the coherent light beam through the first optical element is transmitted to the first scanning unit through the second scanning unit, and the scanning speed of the first scanning unit is greater than the scanning speed of the second scanning unit.

[0055] In combination with the third aspect, in certain implementations of the third aspect, the light beam emitted by the emission unit may include a coherent light beam.

[0056] In a fourth aspect, a control device is provided, which includes: a memory for storing a computer program; and a processor for executing the computer program stored in the memory, so that the device performs the method in the above-mentioned first aspect and any possible implementation thereof.

[0057] In a fifth aspect, a detection system is provided, which includes: an emitting unit, a first optical element, a first scanning unit and a control platform, and the control platform includes the device of the third aspect or the fourth aspect and any possible implementation thereof.

[0058] In a sixth aspect, a computer program product is provided, comprising: a computer program code, which, when executed on a computer, enables the computer to execute the method in the second aspect and any possible implementation thereof.

[0059] In the seventh aspect, a computer-readable storage medium is provided, wherein the computer-readable medium stores a computer program. When the computer program runs on a computer, the computer executes the method in the second aspect and any possible implementation thereof.

[0060] In an eighth aspect, a chip is provided, which includes a circuit for executing the method in the above-mentioned second aspect and any possible implementation thereof.

[0061] In a ninth aspect, an intelligent driving device is provided, which includes the apparatus of the third aspect or the fourth aspect and any possible implementation thereof, or a system including the fifth aspect and any possible implementation thereof.

[0062] Exemplarily, the intelligent driving device may include a vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] FIG1 is a schematic diagram of the time-frequency characteristics of a frequency modulated continuous wave provided in an embodiment of the present application;

[0064] FIG2 is a schematic diagram of a detection scenario provided in an embodiment of the present application;

[0065] FIG3 is a schematic diagram of another detection scenario provided in an embodiment of the present application;

[0066] FIG4 is a schematic diagram of another detection scenario provided in an embodiment of the present application;

[0067] FIG5 is a schematic diagram of a system architecture provided in an embodiment of the present application;

[0068] FIG6 is a flow chart of a control method provided in an embodiment of the present application;

[0069] FIG7 is a schematic diagram of another detection scenario provided in an embodiment of the present application;

[0070] FIG8 is a schematic diagram of another detection scenario provided in an embodiment of the present application;

[0071] FIG9 is a schematic diagram of a scanning trajectory of a detection light spot provided in an embodiment of the present application;

[0072] FIG10 is a schematic diagram of another scanning trajectory of a detection light spot provided in an embodiment of the present application;

[0073] FIG11 is a schematic diagram of another detection scenario provided in an embodiment of the present application;

[0074] FIG12 is a schematic diagram of another detection scenario provided in an embodiment of the present application;

[0075] FIG13 is a schematic block diagram of a control device provided in an embodiment of the present application;

[0076] FIG14 is a schematic block diagram of another control device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0077] The technical solution in this application will be described below with reference to the accompanying drawings.

[0078] For example, according to the form of the detection signal emitted, radar can be divided into pulse radar and continuous wave radar. Pulse radar can detect surrounding target objects through high-frequency pulse signals. Continuous wave radar can include single-frequency continuous wave radar, multi-frequency continuous wave radar and frequency modulated continuous wave radar. Frequency modulated continuous wave (FMCW) radar can detect the distance and speed of surrounding objects by sending FMCW signals with lower cost equipment. The frequency modulation method can include triangle wave modulation, sawtooth wave modulation, etc., and an FMCW signal whose frequency changes with time can be obtained by frequency modulation. For lidar, the detection signal is a light signal, which can also be called a detection beam.

[0079] The detection signal emitted by the FMCW lidar can generate a return signal after being reflected by the target object, and the detection system can receive this return signal. Based on the return signal of the detection signal and the local oscillator signal of the detection signal, an intermediate frequency photocurrent signal (also called an intermediate frequency signal) can be obtained through beat frequency. This intermediate frequency signal can include time delay information of the target object, from which the distance to the target can be obtained. When the target object has a velocity in the direction pointed by the detection signal (also called radial velocity), due to the Doppler effect, there will be a difference between the frequency of the return signal and the frequency of the detection signal. The following uses triangle wave modulation as an example and is combined with Figure 1 to illustrate the FMCW radar.

[0080] For example, FIG1 is a schematic diagram of the time-frequency characteristics of a frequency modulated continuous wave provided in an embodiment of the present application. Taking a triangular wave signal as the detection signal as an example, the time-frequency characteristics of the corresponding return signal and intermediate frequency signal can be shown in FIG1. ​​The translation of the return signal relative to the detection signal along the time axis can correspond to the distance information of the target object. The translation of the return signal relative to the detection signal along the frequency axis can correspond to the speed information of the target. By beating the local oscillator signal and the return signal, a beat frequency signal can be obtained.

[0081] Let R represent the relative distance between the target and the radar, v the relative velocity, and f1 and f2 the maximum and minimum values ​​of the beat signal in the frequency domain, respectively. The distance and velocity of the target relative to the radar satisfy the following relationship: R ∝ (f1 + f2), v ∝ (f1 - f2).

[0082] For lidar, the use of a continuous-wave coherent detection mechanism may lead to problems such as speckle, scanning decoherence, and transmit-receive delay angles.

[0083] 1. Speckle effect:

[0084] The surface of a target object inevitably exhibits roughness, meaning its microstructure inevitably exhibits high undulations. Each point on a rough surface can be understood as a combination of countless point or surface sources. When the probe beam emitted by a lidar strikes the rough surface of the target object, each point or surface source on the rough surface can reflect or transmit the incident light, with the reflected or transmitted light at different points exhibiting different phases. Due to the large number of independent point or surface sources, the reflected or projected light exhibits dramatic and irregular variations in intensity over time.

[0085] When the laser radar's light spot illuminates the target surface, the backscattered light generated by the spot elements at different locations within a single spot will experience different time delays due to the influence of the target surface's microstructure. This manifests as varying degrees of phase modulation of the backscattered light, causing wavefront distortion. Because the surface height fluctuations of the target object are highly random, the phase of the backscattered light is correspondingly randomly modulated, manifesting as the coherent superposition of the backscattered light spot elements within the receiving field of view. Since the phase modulation of each spot element is random, some locations experience coherence enhancement and others experience coherence cancellation, ultimately appearing as alternating bright and dark spots, the so-called speckle. The speckle effect is particularly pronounced when the wavelength of the probe light is of the same order of magnitude as the microscopic height fluctuations of the target object's surface.

[0086] When the system receives the speckle, it beats the local oscillator light to obtain an intermediate frequency signal. This intermediate frequency signal can satisfy: I(t)=Aexp[j(ω(t)+θ)]=∑E0(x,y;t)E s (x,y;t)

[0087] Where x and y represent different positions on the spot, and t represents time. A represents the frequency of the intermediate frequency signal, θ represents the initial phase of the intermediate frequency signal, and ω(t) represents the angular frequency of the intermediate frequency signal. E0(x, y; t) represents the complex amplitude of light at different positions within the spot of the local oscillator signal (abbreviated as the local oscillator spot), and E s (x, y; t) represents the complex amplitude of light at different locations within the return signal's spot (referred to as the return spot). Because the return spot is modulated by the rough surface of the target object, its amplitude and phase are altered compared to the detection signal's spot (referred to as the detection spot), preventing it from fully coherently reinforcing the local oscillator spot to produce ideal coherent detection. Therefore, the amplitude A and initial phase θ of the intermediate frequency signal are both dependent on the surface characteristics of the target object. Generally speaking, the amplitude A of the intermediate frequency signal is lower than the ideal amplitude, resulting in a lower signal-to-noise ratio (SNR) in the actual return signal than in the ideal return signal.

[0088] When the detection spot is irradiated at different positions on the target surface, the amplitude and phase of the corresponding intermediate frequency signal will change accordingly due to the changes in the surface characteristics of the target object.

[0089] 2. Scanning decoherence

[0090] Since the intermediate frequency signal is affected by the surface characteristics of the target object, when the detection spot quickly scans across the surface of the target object, the intermediate frequency signal corresponding to different sampling time points will change.

[0091] For example, Figure 2 is a schematic diagram of a detection scenario provided by an embodiment of the present application. At a certain moment, a detection beam is irradiated on the surface of a target object, forming a detection spot. The spot boundary shown in Figure 2 can be understood as the boundary of the beam corresponding to the spot during its propagation process.

[0092] At different sampling times, the detection spot is at different positions on the surface of the target object. For example, the intermediate frequency signal corresponding to the nth sampling time point can be expressed as: I(n) = A n exp[j(ω(n)+θ n )]. Among them, A n and θ n It can represent the amplitude and initial phase of the intermediate frequency signal corresponding to the nth sampling time point, where n is a positive integer.

[0093] In an ideal scenario, as the scanning progresses, the detection spot moves on the surface of the target object, and the A of the intermediate frequency signal n and θ n It does not change with the change of sampling time. However, due to the phase modulation of the light beam by the microstructure, the A of the intermediate frequency signal in the actual scene n and θ n changes with the sampling time. The phase θ n Variations in sampling time can cause additional phase modulation of the IF signal, a phenomenon known as scanning decoherence. These phase variations in the IF signal's spectrum can also affect the LiDAR's speed and ranging performance.

[0094] 3. Transmit and receive delay angle

[0095] In scenarios where a scanning mechanism is employed, the probe light emitted by the LiDAR is directed toward the target object through the scanning mechanism. As the scanning proceeds, the probe beam can strike different locations on the target object's surface. Scattered light reflected from the target object's surface is received by the detection system via the scanning mechanism. The detection system may include a receiving bin, which can be the area within the sensor where the photodiodes are distributed. This scattered light can be received by using methods such as apertures or lenses to ensure that the entire light spot falls within the receiving bin.

[0096] Because the relative distances between different targets and the radar vary, the return signal's delay relative to the detection signal varies accordingly. The scanning mechanism's rotation angles may differ under different delays, resulting in different transmit and receive delay angles. This results in varying degrees of deviation of the beam spot center from the equivalent receiving element. This deviation varies with the relative distance between the target and the radar.

[0097] For example, FIG3 is a schematic diagram of another detection scenario provided by an embodiment of the present application. As shown in FIG3 , the detection system 100 may include a transmitting unit, a receiving unit, and a scanning mechanism. The detection system 100 may include a lidar system. The light beam emitted by the transmitting unit may be irradiated onto the surface of the target object via the scanning mechanism. When the scanning mechanism is in different postures, the detection light beam irradiates different positions on the surface of the target object. The light reflected by the surface of the target object may be captured by the receiving unit via the scanning mechanism.

[0098] In one embodiment, as shown in FIG3 , taking target 2 as an example, during a sampling period, when the light beam emitted by the emitting unit is emitted by the scanning mechanism, the scanning mechanism is in posture M. When the reflected light from target 2 enters the scanning mechanism, the scanning mechanism may be in posture N. In other words, between the moment the probe light beam is emitted by the scanning mechanism and the moment the return light enters the scanning mechanism, the posture of the scanning mechanism may change due to its actuation.

[0099] In another embodiment, as shown in Figure 3, a scanning mechanism can be used to scan the light beam emitted by the transmitting unit across the surfaces of targets 1 and 2. Due to the different relative distances between targets 1 and 2 and the radar, the return light corresponding to targets 1 and 2 will have different time delays relative to the detection beam. During the scanning process, the center of the light spot focused by the lens will deviate to varying degrees on the equivalent receiving surface element.

[0100] When the scanning mechanism's scanning speed is high and the scanning mechanism rotates through a large angle during a sampling cycle (for example, a large difference between posture M and posture N), the return light spot on the receiving surface may shift by microns. This means that the equivalent receiving surface of the optical fiber or waveguide on the receiving side will experience a micron-level shift. Consequently, the relative distance between the target object and the radar may deviate by tens or even hundreds of meters. This deviation severely impacts the ranging and velocity measurement performance of the lidar.

[0101] In addition, since the relative position relationship between the target object and the radar is unknown, it is difficult to compensate for the transmit and receive delay angles by pre-biasing. For coherent detection, it is also impossible to simply compensate for the transmit and receive delay angles by increasing the area of ​​the transmitting unit or using multimode fiber to couple the return signal. On the one hand, increasing the area of ​​the transmitting unit requires coupling a larger area of ​​local oscillator light, which will lead to a significant increase in the system's shot noise, thereby reducing the signal-to-noise ratio of the return signal. On the other hand, using multimode fiber to couple the return signal will result in decoherence effects between different modes, which will also lead to a decrease in detection efficiency.

[0102] It should be noted that the description of the detection system in FIG3 is only an example, and the embodiments of the present application do not limit the specific structure of the detection system. For example, in some possible implementations, the receiving unit can be coupled to the transmitting unit. For another example, different from the method shown in FIG3, in some possible implementations, the receiving unit and the transmitting unit can be coaxially arranged. For another example, in some possible implementations, the scanning mechanism can include multiple scanning units to achieve scanning in multiple dimensions. The scanning unit can include a galvanometer, an oscillating mirror, a rotating mirror, etc.

[0103] For example, Figure 4 is a schematic diagram of another detection scenario provided by an embodiment of the present application. Figure 4 shows a scanning method of the detection system 200, wherein the receiving unit (not shown in Figure 4) of the detection system 200 can be configured similarly to the detection system 100.

[0104] As shown in (a) of Figure 4 , the scanning mechanism in the detection system 200 shown in Figure 4 may include a scanning mirror 1 and a scanning mirror 2. The scanning mirror 1 and the scanning mirror 2 can be understood as a scanning unit respectively. Accordingly, the light beam emitted by the emitting unit can be irradiated to the surface of the target through the scanning mirror 1 and the scanning mirror 2. The scanning mirror 1 can rotate along the rotation direction 1, and the scanning mirror 2 can rotate along the rotation direction 2. The rotation direction 1 and the rotation direction 2 can be set orthogonally. By rotating the scanning mirror 1 and the scanning mirror 2, scanning in multiple dimensions can be achieved.

[0105] In some possible implementations, scanning mirror 1 can be implemented by a galvanometer, and the rotation of scanning mirror 1 can be achieved by a stepper motor. Scanning mirror 2 can be implemented by a rotating mirror, and its scanning method can be continuous scanning. In some possible implementations, scanning mirror 1 and / or scanning mirror 2 can also be implemented by other methods, which are not limited in the embodiments of the present application.

[0106] Exemplarily, assuming that the posture of the scanning mirror 1 remains unchanged while the scanning mirror 2 rotates along the rotation direction 2, the detection light beam moves along the scanning direction 1 as shown in (b) of Figure 4 on the surface of the target object. When the posture of the scanning mirror 2 remains unchanged while the scanning mirror 1 rotates along the rotation direction 1, the detection light beam moves along the scanning direction 2 on the surface of the target object. For example, when the scanning mirror 1 is in posture A and the scanning mirror 2 is in posture 1, the light spot boundary #1 shown in (a) of Figure 4 can be understood as the boundary of the light beam emitted by the emitting unit in this scene during its propagation process; the corresponding detection light spot can be A-1 in (b) of Figure 4. For another example, when the scanning mirror 1 is in posture A and the scanning mirror 2 is in posture 2, the light beam emitted by the emitting unit in this scene can be represented by the light spot boundary #2 in its propagation path; the corresponding detection light spot can be A-2 in (b) of Figure 4. For another example, when scanning mirror 1 is in posture B and scanning mirror 2 is in posture 1, the detection spot is shown as B-1 in Figure 4(b); when scanning mirror 1 is in posture B and scanning mirror 2 is in posture 2, the detection spot is shown as B-2 in Figure 4(b). As can be seen in Figure 4(a), when the posture of scanning mirror 2 changes, the direction of the light beam irradiated on the target surface changes.

[0107] In one embodiment, the scanning speed of scanning mirror 2 can be much faster than that of scanning mirror 1. That is, a combination of slow and fast scanning is employed. Accordingly, scanning mirror 1 can correspond to a fast scanning unit, and scanning mirror 2 can correspond to a slow scanning unit. Scanning mirror 1 can also be referred to as a slow scanning mirror, and scanning mirror 2 can also be referred to as a fast scanning mirror. For example, when the slow scanning mirror is in posture A, because the fast scanning mirror rotates much faster than the slow scanning mirror, when the posture of the fast scanning mirror changes from posture 1 to posture 2, it can be considered that the posture of the slow scanning mirror has not changed. Accordingly, the detection light spot sweeps across the surface of the target object along scanning direction 1. For another example, when the slow scanning mirror rotates to posture B, the fast scanning mirror can rotate again along rotation direction 2 from posture 1 to posture 2, thereby achieving multi-dimensional scanning of the target. For another example, scanning mirror 1 in posture A and scanning mirror 2 in posture 1, and scanning mirror 1 in posture A and scanning mirror 2 in posture 2, can correspond to the scanning mechanism in system 100 being in posture M and posture N, respectively. Similarly, the system 200 may have problems with the transmit and receive delay angle and scanning decoherence.

[0108] As mentioned above, when the lidar detects the distance and speed of the target object by scanning, there will inevitably be problems with scanning decoherence and transmission and reception delay angles, resulting in additional phase modulation and a reduction in the signal-to-noise ratio of the return signal, which seriously affects the system's ranging and speed measurement performance.

[0109] In view of this, an embodiment of the present application provides a control method and a control device, which can compensate for and reduce the impact of the scanning process of the scanning unit on the propagation of the light beam through the deflection effect of the first optical element on the propagation direction of the light beam, and can reduce the impact of the scanning unit on the performance of laser speed and ranging.

[0110] For example, FIG5 is a schematic diagram of a system architecture provided in an embodiment of the present application. As shown in FIG5 , the system 300 may include a transmitting unit 310, a first scanning unit 320, and a first optical element 330. The first optical element 330 is disposed between the transmitting unit 310 and the first scanning unit 320. For example, the first optical element 330 is disposed on the propagation path of the light beam emitted by the transmitting unit 310. On this propagation path, the light beam is sequentially transmitted to the first optical element 330 and the first scanning unit 320. The first optical element 330 can be used to change the propagation path of the light beam emitted by the transmitting unit 310.

[0111] For example, the transmitting unit 310 can be used to transmit a light beam. The first scanning unit 320 can be used to scan the light beam from the first optical element 330. The first optical element 330 can be used to receive a first light beam at a first time point and emit a first detection beam; receive a second light beam at a second time point and output a second detection beam. The angle between the first light beam and the first detection beam is a first angle, and the angle between the second light beam and the second detection beam is a second angle. The angular difference between the first angle and the second angle is determined based on the scanning speed of the first scanning mechanism 320. For example, the light beam emitted by the transmitting unit 310 can be a coherent light beam.

[0112] Exemplarily, the first time point and the second time point may be any time points. The first light beam may include the light beam emitted by the emitting unit 310 at the first time point, or the light beam emitted by the emitting unit 310 that reaches the first optical element 330 at the first time point. Similarly, the second light beam may include the light beam emitted by the emitting unit 310 at the second time point, or the light beam emitted by the emitting unit 310 that reaches the first optical element 330 at the second time point. For the first optical element, the first detection beam may be the outgoing light corresponding to the first light beam; accordingly, the first light beam may be the outgoing light corresponding to the first detection beam. Similarly, the second detection beam may be the outgoing light corresponding to the second light beam, and accordingly, the second light beam may be the incident light corresponding to the second detection beam.

[0113] In some possible implementations, the first optical element 330 can deflect the light beam through reflection. For example, the first optical element 330 can include an optical element such as a galvanometer or an oscillating mirror that deflects the light beam through reflection. For another example, by adjusting the posture of the galvanometer or oscillating mirror, the deflection effect on the propagation direction of the light beam can be changed.

[0114] In some possible implementations, the first optical element 330 can deflect the light beam through refraction. For example, the first optical element can include a lens, a photoelectric crystal, a magnetoelectric crystal, a pyroelectric crystal, a liquid crystal, etc. For another example, by adjusting the lens's posture, the light beam's propagation path within the lens can be altered to meet the desired light beam deflection effect in different scenarios. For another example, by adjusting the refractive index of the photoelectric crystal, its deflection effect on the propagation direction of the light beam can be changed.

[0115] In some possible implementations, the system 300 may further include a receiving unit 340. The light beam emitted by the transmitting unit 310 passes through the first optical element 330 and is then irradiated by the first scanning unit 320. After passing through the first scanning unit 320, it can be irradiated onto the surface of the target object. The return light of the probe beam generated by reflection from the target object can be received by the receiving unit 340 via the first scanning unit 320. The receiving unit 340 can be coaxial with the transmitting unit 310 or not, and this is not limited in this application.

[0116] In one embodiment, the functions and uses of the transmitting unit 310 and the receiving unit 340 are the same or similar to those of the transmitting unit and the receiving unit in the systems 100 and 200 .

[0117] In some possible implementations, the first optical element may be disposed between the first scanning unit 320 and the transmitting unit 310, and between the first scanning unit 320 and the receiving unit 340. In other words, the first optical element may be disposed on the propagation path of the light beam emitted by the transmitting unit, and also on the propagation path of the return light.

[0118] In some possible implementations, the system 300 may further include other units or elements. For example, a collimating lens may be provided between the transmitting unit 310 and the first optical element 330. For another example, a collimating lens may be provided between the receiving unit 340 and the first optical element 330.

[0119] For example, the first scanning unit 320 may be disposed in a scanning mechanism, and the first optical element 330 may be independent of the scanning mechanism, or may be coupled to the scanning mechanism, which is not limited in this embodiment of the present application.

[0120] In some possible implementations, the scanning mechanism may include multiple scanning units, including the first scanning unit 320, to enable scanning in multiple directions. For example, the system 300 may further include a second scanning unit 350, which may be disposed between the first optical element 330 and the first scanning unit 320. The second scanning unit 350 may be configured to transmit the light beam emitted by the first optical element 330 to the first scanning unit 320. The second scanning unit 350 has a slower scanning speed than the first scanning unit. For example, the scanning directions of the second scanning unit 350 and the first scanning unit 320 may be orthogonal to enable scanning in two directions. For another example, the second scanning unit 350 may transmit the light beam emitted by the first optical element 330 to the first scanning unit 350 by changing the propagation direction of the light beam. For another example, the second scanning unit 350 may include a slow scanning unit, and the first scanning unit 320 may include a fast scanning unit. For another example, the second scanning unit 350 and the first scanning unit 320 may be coupled to the same scanning mechanism.

[0121] For example, FIG6 is a flow chart of a control method provided in an embodiment of the present application. The method 400 can be executed by a lidar system, or can be executed by an intelligent driving device equipped with the lidar system, or can be executed by a control device corresponding to the lidar system, or can be executed by a chip or processor in the control device. The control device corresponding to the lidar system can be coupled to the system, or can be independent of the system. The method 400 may include:

[0122] S410: Obtain a scanning speed of a first scanning unit.

[0123] For example, scanning of the light beam from the first optical element can be achieved by changing the posture of the first scanning unit. For example, at a first time point and a second time point, the posture of the first scanning unit 320 can be a first scanning posture and a second scanning posture, respectively. The first scanning unit 320 will produce different deflection effects on the light beam when in different scanning postures. In other words, the angle between the light beam from the first optical element 330 and the light beam emitted after passing through the first scanning unit 320 is determined by the scanning posture of the first scanning unit 320. The change in this angle between different moments is determined by the change in the scanning posture of the first scanning unit 320.

[0124] In one embodiment, for two given time points, such as time point #1 and time point #2, it is assumed that the first scanning unit 320 scans the light beam from the first optical element 330 at a constant speed. The change in the posture of the first scanning unit 320 between the two time points is determined by the scanning speed of the first scanning unit.

[0125] In another embodiment, when the first scanning unit 320 scans at a varying speed, for given two time points, the change in the posture of the first scanning unit 320 between the two time points is determined by the scanning speed of the first scanning unit 330 between the two time points.

[0126] In some possible implementations, the scanning speed of the first scanning unit 320 may be determined by acquiring the postures of the first scanning unit 320 at multiple time points.

[0127] S420, determine the angular difference between the first steering angle and the second steering angle based on the scanning speed of the first scanning unit, the first steering angle includes the angle between the first light beam and the first detection beam at a first time point, the first detection beam is the light beam emitted by the first optical element, the second steering angle includes the angle between the second light beam and the second detection beam at a second time point, the second detection beam is the light beam emitted by the second light beam through the first optical element, the first optical element is arranged between the emitting unit and the first scanning unit, and the first light beam and the second light beam are emitted by the emitting unit.

[0128] For example, reference may be made to the description in the system architecture 300 regarding the first time point, the second time point, the first steering angle, and the second steering angle.

[0129] In some possible implementations, the first steering angle is generated by reflection when the first optical element 330 is at a first reflection angle, and the second steering angle is generated by reflection when the first optical element 330 is at a second reflection angle. The change in the reflection angle of the first optical element 330 is determined according to the scanning speed of the first scanning unit 320.

[0130] For example, in a scenario where the first optical element 330 deflects a light beam through reflection, the deflection effect of the light beam can be adjusted by adjusting the reflection angle (or posture) of the first optical element 330. Similarly, in a scenario where the first optical element 330 deflects a light beam through refraction, the propagation path of the light beam in the lens can be adjusted by adjusting the posture of the first optical element 330, thereby adjusting the light beam deflection effect.

[0131] In one embodiment, it is assumed that the light beam emitted by the emitting unit 310 maintains its propagation path unchanged before reaching the first optical element 330. When the first optical element 330 is at different reflection angles, the light beam will be emitted from the first optical element 330 at different angles. Since the propagation path of the incident light beam remains unchanged, the result is that the change in the angle between the incident light beam and the outgoing light beam depends on the change in the reflection angle of the first optical element 330. In other words, according to the reflection angle (or posture) of the first optical element 330, its deflection effect on the light beam, such as the first steering angle and the second steering angle, can be determined. In other words, the angular difference between the first steering angle and the second steering angle can be obtained based on the posture of the first optical element 330 at the corresponding time point. The change in the posture of the first optical element 330 between corresponding time points is determined by the movement speed of the first optical element 330.

[0132] For example, in a scenario where the first optical element 330's deflection effect on the light beam is adjusted by adjusting its posture, determining the angular difference between the first steering angle and the second steering angle based on the scanning speed of the first scanning unit 320 may include determining the movement speed of the first optical unit 330 based on the scanning speed of the first scanning unit 320. For example, based on the movement speed of the first optical unit 330, changes in the posture of the first optical element 330 between corresponding time points can be determined, and accordingly, changes in the deflection effect of the first optical element 330 on the light beam between corresponding time points can be determined.

[0133] In one embodiment, during the first sampling period, the rotation speed of the first optical element 330 is the same as the scanning speed of the first scanning unit 320, and the first optical element 330 and the first scanning unit 320 deflect the light beam in opposite directions. The first sampling period can be any sampling period. For example, the first time point and the second time point can be any two time points within the first sampling period.

[0134] In another embodiment, in the first half of the first sampling period, the rotation speed of the first optical element 330 is zero; in the second half of the first sampling period, the rotation speed of the first optical element 330 is twice the scanning speed of the first scanning unit 320, and the first optical element 330 and the first scanning unit 320 have opposite deflection directions of the light beam.

[0135] In the present application, the movement speed of the first optical unit 330 is determined according to the scanning speed of the first scanning unit 320, and the angular difference between the first steering angle and the second steering angle can be controlled without the need to measure the two in real time, which can simplify the control of the light beam deflection effect of the first optical element.

[0136] In some possible implementations, in scenarios where the first optical element 330 deflects a light beam through refraction, the light beam deflection effect can be controlled by controlling the refractive index of the first optical element 330. For example, assuming that the first optical element 330 includes a photoelectric crystal, the refractive index of the photoelectric crystal can be controlled according to the scanning speed of the first scanning unit 320 to control the light beam deflection effect of the first optical element.

[0137] In some possible implementations, a second scanning unit is provided between the first optical element 330 and the first scanning unit 320 , and the second scanning unit can transmit the light beam emitted by the first optical element 330 to the first scanning unit 320 .

[0138] The following briefly describes the working mode of the detection system involved in the embodiment of the present application with reference to Figures 7 to 12. The systems involved in Figures 7 to 12 can be understood as expansions or variations of the system 300.

[0139] For example, Figure 7 is a schematic diagram of a detection scenario provided by an embodiment of the present application. As shown in Figure 7, system 500 may include a transmitting unit, a first optical element, a scanning mirror 1, and a scanning mirror 2. Scanning mirror 1 in system 500 may correspond to second scanning unit 350 in system 300, and scanning mirror 2 may correspond to first scanning unit 320. System 500 can be understood as an extension or variation of system 300, or as an addition of a first optical element to system 200.

[0140] In one embodiment, when the scanning mirror 1 is in posture A and the scanning mirror 2 is in posture 1, the boundary of the propagation path of the light beam emitted by the emitting unit may be spot boundary #1. In the case where the first optical element is not provided (taking system 200 as an example), when the scanning mirror 1 is in posture A and the scanning mirror 2 is in posture 2, the boundary of the propagation path of the light beam emitted by the emitting unit may be spot boundary #2, as shown in (a) in FIG4 . In the case where the first optical element is provided, according to the scanning speed of the scanning mirror 2, by adjusting the deflection effect of the first optical element on the light beam, when the scanning mirror 1 is in posture A and the scanning mirror 2 is in posture 2, the boundary of the light beam in its propagation path may be spot boundary #3, as shown in FIG7 . In this way, the influence of the scanning decoherence caused by scanning and the transmit and receive delay angle on the speed and ranging performance of the laser radar can be reduced.

[0141] In some possible implementations, the first optical element may include a galvanometer. For example, as shown in FIG8 , FIG8 is a schematic diagram of a detection scenario provided in an embodiment of the present application. As shown in FIG8 , system 600 can be understood as a variation or extension of systems 300 and 500 , and the scanning mirror 3 in system 600 can correspond to the first optical element in systems 300 and 500 .

[0142] For example, in system 600, rotation direction 1 and rotation direction 2 can be arranged orthogonally. Rotation direction 1 and rotation direction 3 can also be arranged orthogonally. Assuming that scanning mirror 2 is a continuously rotating mirror and scanning mirror 3 is a galvanometer or oscillating mirror, scanning mirror 3 can change the propagation direction of the light beam through reflection. Assuming that the scanning speed of scanning mirror 1 is much lower than the scanning speed of scanning mirror 2, the rotation of scanning mirror 1 can be ignored during a sampling period.

[0143] In one embodiment, during the same sampling period, the scanning mirrors 2 and 3 may rotate at the same speed, but in opposite directions. For example, the rotation direction 2 may be clockwise and the rotation direction 3 may be counterclockwise; or vice versa.

[0144] As shown in Figure 8, assuming that the scanning mirror 2 rotates clockwise, the scanning mirror 3 can be controlled to rotate counterclockwise. For example, in the same sampling period, the change in the direction of the light beam caused by the scanning of the scanning mirror 2 can be compensated by controlling the rotation of the scanning mirror 3. After the sampling period ends, the scanning mirror 3 can be controlled to return to its initial state. In the next sampling period, the scanning mirrors 2 and 3 can be controlled to rotate in the previous sampling period, so that the change in the direction of the light beam caused by the scanning mirror 2 in the sampling period can be compensated by controlling the rotation of the scanning mirror 3. In this reciprocating manner, the direction of the light beam emitted by the scanning mechanism can be controlled. The scanning trajectory of the detection light spot in this scenario is introduced in conjunction with Figure 9 below.

[0145] As shown in FIG9 , when the scanning mirror 3 is not provided or is inactive, the scanning trajectory formed by the light beam emitted by the scanning mirror 2 and irradiated onto the target object when the scanning mirror 2 rotates can be scanning trajectory 1. When the rotation speed of the scanning mirror 3 is the same as that of the scanning mirror 2 but the two rotate in opposite directions, the direction of the light beam emitted by the scanning mirror 2 can remain unchanged during a sampling cycle as the scanning mirror 2 rotates. Due to the relative position between the scanning mirror 2 and the scanning mirror 3, the light beam emitted by the scanning mirror 2 may shift in the scanning direction during a scanning cycle. For example, as shown in FIG8 , as the scanning mirror 2 changes from posture 1 to posture 2, the light spot boundary moves from light spot boundary #1 to light spot boundary #3 by controlling the rotation of the scanning mirror 3. Accordingly, the scanning trajectory of the detection light spot can be scanning trajectory 2, as shown in FIG9 . By adjusting the relative position between the scanning mirror 2 and the scanning mirror 3, the amount of this shift can be reduced.

[0146] In this embodiment of the present application, by controlling the rotation of scanning mirror 3, the length of the scanning trajectory of the detection light spot on the target object surface can be reduced, thereby suppressing the scanning decoherence caused by the scanning mechanism. Furthermore, because the direction of the detection light emitted by scanning mirror 2 remains unchanged during the same sampling period, the problem of reduced return signal power caused by the transmission and reception delay angle can be greatly improved, and the signal-to-noise ratio of the return signal can be improved, thereby improving the ranging and speed measurement performance of the lidar.

[0147] In another embodiment, the rotation speed of scanning mirror 3 can be different at different stages of a scanning cycle. For example, in the first half of a sampling cycle, scanning mirror 3 may not rotate; in the second half of the sampling cycle, the rotation direction of scanning mirror 3 and scanning mirror 2 can be opposite, and the rotation speed of scanning mirror 3 can be twice that of scanning mirror 2. The scanning trajectory of the detection light spot in this scenario is described below with reference to Figure 10.

[0148] As shown in Figure 10, when scanning mirror 3 is not provided or is inoperative, the scanning trajectory formed by the light beam emitted by scanning mirror 2 and irradiated onto the target object when scanning mirror 2 rotates can be scanning trajectory 1. When scanning mirror 3 does not rotate in the first half of the sampling period, but rotates in the opposite direction of scanning mirror 2 at twice the speed of scanning mirror 2 in the second half of the sampling period, the scanning trajectory formed by the light beam emitted by scanning mirror 2 and irradiated onto the target object can be scanning trajectory 3. In other words, within one sampling period, the detection light spot can scan the target object surface twice in opposite directions along the same scanning trajectory.

[0149] In this embodiment, upon receiving the return signal from the sampling period, the decoherence effect of the second scan can be compensated by extracting the phase modulation information obtained from the first scan. This allows the phase modulation effect of the microstructure on the light beam to be determined, thereby reducing the impact of the scan on the laser speed and ranging performance, and improving the ranging and speed measurement performance of the LiDAR.

[0150] In some possible implementations, scanning mirror 1 , scanning mirror 2 , and scanning mirror 3 may be coupled in the same scanning mechanism.

[0151] In some possible implementations, the beam pointing adjustment mechanism may include a lens. For example, as shown in FIG11 , FIG11 is a schematic diagram of another detection scenario provided by an embodiment of the present application. As shown in FIG11 , system 700 can be understood as a variation or extension of systems 300 and 500 , and lens 1 in system 700 can correspond to the first optical element.

[0152] For example, in system 700, when lens 1 rotates along rotation direction 4, the deflection effect of lens 1 on the light beam will change. For example, as shown in FIG11(a), ignoring the rotation of scanning mirror 1, when scanning mirror 2 rotates from posture 1 to posture 2, by controlling lens 1 to rotate along rotation axis 1 to the corresponding posture, the boundary of the light beam on its propagation path can be changed from spot boundary #1 to spot boundary #3.

[0153] In one embodiment, lens 1 may include surface 1 and surface 2 disposed opposite each other. Surface 1 may be disposed on one side of the emitting unit, and surface 2 may be disposed on one side of the scanning mirror 1. Surface 1 may be a flat surface, and surface 2 may be a curved surface. Surface 1 and surface 2 may correspond to a first flat surface and a first curved surface in system 300, respectively, and rotation axis 1 may correspond to a first axis in system 300.

[0154] As shown in (b) in Figure 11, when the lens 1 rotates along the rotation axis 1, the light beam emitted by the emitting unit can illuminate different positions of the surface 1, and accordingly, be emitted from different positions of the surface 2. The dotted line shown in (b) in Figure 11 can represent the exit position of the light beam on the surface 2 during the rotation of the lens 1 along the rotation axis 1. For example, the curvature of the surface 2 can change linearly along the dotted line shown in (b) in Figure 11, so that when the lens 1 rotates, the angle between the first incident light and the first exit light can change linearly. For another example, by controlling the rotation speed of the lens 1 according to the rotation speed of the scanning mirror 2, the scanning trajectory of the detection light spot can be as shown in scanning trajectory 2 or scanning trajectory 3.

[0155] In some possible implementations, the first optical element may include an electro-optical crystal. For example, as shown in FIG12 , FIG12 is a schematic diagram of another detection scenario provided by an embodiment of the present application. System 800 can be understood as a variation or extension of systems 300 and 500 , and the electro-optical crystal in system 800 may correspond to the first optical element in systems 300 and 500 .

[0156] For example, in system 800, the electro-optical crystal can be tilted relative to the light beam emitted by the emission unit. In system 800, the refractive index of the electro-optical crystal can be adjusted to adjust the light beam deflection effect of the electro-optical crystal. For example, by controlling the refractive index of the electro-optical crystal based on the rotation speed of scanning mirror 2, the scanning trajectory of the detection light spot can be adjusted as shown in scanning trajectory 2 or scanning trajectory 3.

[0157] The method provided in the embodiments of the present application is described in detail above with reference to Figures 5 to 12. The apparatus provided in the embodiments of the present application will be described in detail below with reference to Figures 13 and 14. The description of the apparatus embodiment corresponds to the description of the method embodiment. Therefore, for any details not described in detail, reference can be made to the method embodiment above.

[0158] For example, FIG13 shows a schematic block diagram of a control device (hereinafter referred to as device 1000 ) provided in an embodiment of the present application. The device may include an acquisition unit 1010 and a processing unit 1020 .

[0159] The apparatus 1000 may include a unit for executing any one of the methods in FIG. 5 to FIG. 12 , and each unit in the apparatus 1000 may be used to execute a corresponding process in any one of the method embodiments in FIG. 5 to FIG. 12 .

[0160] When the apparatus 1000 is used to execute the method 400 in FIG. 6 , the acquiring unit 1010 may be used to execute step S410 in the method 400 , and the processing unit 1020 may be used to execute step S420 in the method 400 .

[0161] Specifically, the acquisition unit 1010 can be used to acquire a scanning speed of the first scanning unit 320. The processing unit 1020 can be used to determine an angular difference between a first steering angle and a second steering angle based on the scanning speed of the first scanning unit 320, where the first steering angle includes the angle between a first light beam and a first detection light beam at a first time point, where the first detection light beam is the light beam emitted by the first optical element 330, and the second steering angle includes the angle between a second light beam and a second detection light beam at a second time point, where the second detection light beam is the light beam emitted by the first optical element 330, where the first optical element 330 is disposed between the transmitting unit 310 and the first scanning unit 320, and the first and second light beams are emitted by the transmitting unit 310.

[0162] Exemplarily, the control device may be a laser radar, or it may be a chip or processor in the laser radar, or it may be a terminal (such as a computing platform) in an intelligent driving device for performing signal processing or control on the radar, or a chip or processor in the terminal, or it may be a chip or processor in a control device corresponding to the laser radar, etc.

[0163] In some possible implementations, the first steering angle is generated by reflection when the first optical element 330 is at the first reflection angle, and the second steering angle is generated by reflection when the first optical element 330 is at the second reflection angle. The processing unit 1020 can be configured to determine a change in the reflection angle of the first optical element 330 based on a scanning speed of the first scanning unit 320.

[0164] In some possible implementations, the first optical element 330 includes a rotatable lens, wherein a first side of the rotatable lens includes a first plane, and a second side of the rotatable lens includes a first curved surface. When the rotatable lens moves along a first axis, the curvature of the first curved surface at a first position changes linearly. The first position includes the exit position of the light beam when it exits through the first curved surface. The first axis is perpendicular to the first plane. The processing unit 1020 may be configured to determine the movement speed of the rotatable lens along the first axis based on the scanning speed of the first scanning unit 320.

[0165] In some possible implementations, the first steering angle and the second steering angle are generated by refraction of the first optical element 330 , and the processing unit 1020 may be configured to determine a change rate of a refractive index of the first optical element 330 according to a scanning speed of the first unit.

[0166] In some possible implementations, the processing unit 1020 may be configured to determine the position and / or velocity of the target object based on the return light of the detection light beam and the local oscillator light of the light beam emitted by the emission unit.

[0167] It should be understood that the division of the various units in the above devices is merely a division of logical functions. In actual implementation, they may be fully or partially integrated into a single physical entity, or physically separated. All units in the above devices may be implemented entirely through a processor calling software, entirely through hardware circuits, or partially through a processor calling software, with the remainder implemented through hardware circuits.

[0168] In a specific implementation, the acquisition unit 1010 can be implemented by at least one transceiver or transceiver-related circuitry, and the processing unit 1020 can be implemented by at least one processor or processor-related circuitry. In one example, one or more processors can determine changes in the refractive index of the first optical element 330 based on the scanning speed of the first scanning unit 320. In another example, one or more processors can determine changes in the posture of the first optical element 330 based on the scanning speed of the first scanning unit 320. For example, in a specific implementation, the apparatus 1000 can be an intelligent driving device equipped with a lidar, or a chip or processor within the intelligent driving device.

[0169] For example, FIG14 is a schematic block diagram of another control device 2000 (hereinafter referred to as device 2000) provided in an embodiment of the present application. The device 2000 may include: a processor 2010, an interface circuit 2020, and a memory 2030. The processor 2010, the interface circuit 2020, and the memory 2030 are connected via an internal connection path. The memory 2030 is used to store instructions, and the processor 2010 is used to execute the instructions stored in the memory 2030 and receive / send some parameters through the interface circuit 2020. Optionally, the memory 2030 can be coupled to the processor 2010 via an interface or integrated with the processor 2010.

[0170] It should be noted that the interface circuit 2020 may include, but is not limited to, a transceiver device such as an input / output interface to enable communication between the device 2000 and other devices or communication networks. For example, communication with a radar and / or internal circuits of an intelligent driving device may be achieved through the interface circuit 2020.

[0171] In an embodiment of the present application, a processor is a circuit having a signal processing capability. In one implementation, the processor may be a circuit having the capability to read and execute instructions, such as a central processing unit (CPU), a microprocessor, a graphics processing unit (GPU) (which may be understood as a microprocessor), or a digital signal processor (DSP); in another implementation, the processor may implement certain functions through the logical relationship of a hardware circuit, and the logical relationship of the hardware circuit may be fixed or reconfigurable, such as a hardware circuit implemented by a processor as an application-specific integrated circuit (ASIC) or a programmable logic device (PLD), such as a field programmable gate array (FPGA). In a reconfigurable hardware circuit, the process of the processor loading a configuration document to implement the hardware circuit configuration may be understood as the process of the processor loading instructions to implement the functions of some or all of the above units. In addition, it can also be a hardware circuit designed for artificial intelligence, which can be understood as an ASIC, such as a neural network processing unit (NPU), a tensor processing unit (TPU), a deep learning processing unit (DPU), etc.

[0172] An embodiment of the present application further provides a detection system, which includes an emitting unit, a first optical element, a first scanning unit and a control platform, and the control platform may include the above-mentioned device 1000 or 2000.

[0173] An embodiment of the present application also provides a computer program product, which includes: computer program code, which, when running on a computer, enables the computer to execute any one of the method embodiments in Figures 5 to 12 above, and any possible implementation thereof.

[0174] An embodiment of the present application also provides a computer-readable storage medium, which stores program code or instructions. When the computer program code or instructions are executed by a computer processor, the processor implements any method embodiment in Figures 5 to 12 above, and any possible implementation method thereof.

[0175] An embodiment of the present application also provides a chip, including a circuit, for executing any method embodiment in Figures 5 to 12 above, and any possible implementation thereof.

[0176] An embodiment of the present application also provides a cloud server, which may include the above-mentioned device 1000 or the above-mentioned device 2000.

[0177] An embodiment of the present application also provides an intelligent driving device, which may include any one of the above-mentioned laser radar systems 300 to 800, or may include the above-mentioned device 1000 or 2000, or may include the above-mentioned detection system.

[0178] Exemplarily, the intelligent driving device can be a vehicle. The vehicle involved in the embodiments of the present application is a vehicle in a broad sense, which can be a means of transportation (such as a commercial vehicle, a passenger car, a motorcycle, a flying car, a train, etc.), an industrial vehicle (such as a forklift, a trailer, a tractor, etc.), an engineering vehicle (such as an excavator, a bulldozer, a crane, etc.), agricultural equipment (such as a lawn mower, a harvester, etc.), amusement equipment, a toy vehicle, etc. The embodiments of the present application do not specifically limit the type of vehicle. For example, the vehicle in the present application can include a pure electric vehicle / battery electric vehicle (pure EV / battery EV), a hybrid electric vehicle (hybrid electric vehicle, HEV), a range extended electric vehicle (REEV), a plug-in hybrid electric vehicle (PHEV) or a new energy vehicle (NEV), etc.

[0179] It should be understood that for the convenience and brevity of description, the specific working processes and beneficial effects of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0180] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0181] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0182] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0183] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0184] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0185] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk, or an optical disk.

[0186] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A laser radar system, characterized in that: include: An emitting unit, a first scanning unit and a first optical element, wherein the first optical element is disposed between the emitting unit and the first scanning unit; The transmitting unit is used to: transmit a light beam; The first optical element is used for: receiving a first light beam at a first time point and emitting a first detection light beam, wherein an angle between the first light beam and the first detection light beam is a first steering angle; receiving a second light beam at a second time point and emitting a second detection light beam, wherein an angle between the second light beam and the second detection light beam is a second steering angle, and an angle difference between the second steering angle and the first steering angle is determined according to a scanning speed of the first scanning unit; The first scanning unit is used to scan the light beam from the first optical element.

2. The system according to claim 1, characterized in that The first optical element includes a galvanometer, a swing mirror, a rotatable lens, a photoelectric crystal, a magnetoelectric crystal, a thermoelectric crystal or a liquid crystal element.

3. The system according to claim 1 or 2, characterized in that: The first steering angle is generated by reflection when the first optical element is at a first reflection angle, and the second steering angle is generated by reflection when the first optical element is at a second reflection angle. The change in the reflection angle of the first optical element is determined according to the scanning speed of the first scanning unit.

4. The system according to claim 3, characterized in that In a first sampling period, a rotation speed of the first optical element is the same as a scanning speed of the first scanning unit, and the first optical element and the first scanning unit have opposite deflection directions of the light beam.

5. The system according to claim 3, characterized in that In the first half of the first sampling period, the rotation speed of the first optical element is zero; in the second half of the first sampling period, the rotation speed of the first optical element is twice the scanning speed of the first scanning unit, and the first optical element and the first scanning unit have opposite deflection directions of the light beam.

6. The system according to claim 1 or 2, characterized in that: The first optical element includes a rotatable lens, a first side of the rotatable lens includes a first plane, a second side of the rotatable lens includes a first curved surface, when the rotatable lens moves along a first axis, the curvature of the first curved surface at a first position changes linearly, the first position includes an exit position when the light beam exits through the first curved surface, the first axis is perpendicular to the first plane, and the angular difference between the first steering angle and the second steering angle is generated by the movement of the rotatable lens along the first axis.

7. The system according to claim 6, characterized in that The movement speed of the rotatable lens along the first axis is determined according to the scanning speed of the first scanning unit.

8. The system according to claim 1 or 2, characterized in that: The first optical element includes a photoelectric crystal, a magnetoelectric crystal, a pyroelectric crystal or a liquid crystal element, and a change in the refractive index of the first optical element is determined according to a scanning speed of the first scanning unit.

9. The system according to any one of claims 1 to 8, characterized in that The system also includes a second scanning unit arranged between the first optical element and the first scanning unit, the second scanning unit is used to transmit the detection light beam emitted by the first optical element to the first scanning unit, and the scanning speed of the first scanning unit is greater than the scanning speed of the second scanning unit.

10. The system according to any one of claims 1 to 9, characterized in that The light beam emitted by the emitting unit is a coherent light beam.

11. A control method, characterized in that: include: Acquire the scanning speed of the first scanning unit; The angular difference between the first steering angle and the second steering angle is determined according to the scanning speed of the first scanning unit, the first steering angle includes the angle between the first light beam and the first detection beam at a first time point, the first detection beam is the light beam emitted by the first optical element, the second steering angle includes the angle between the second light beam and the second detection beam at a second time point, the second detection beam is the light beam emitted by the second light beam through the first optical element, the first optical element is arranged between the emitting unit and the first scanning unit, and the first light beam and the second light beam are emitted by the emitting unit.

12. The method according to claim 11, characterized in that The first steering angle is generated by reflection when the first optical element is at a first reflection angle, the second steering angle is generated by reflection when the first optical element is at a second reflection angle, and determining the angle difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit includes: A change in the reflection angle of the first optical element is determined according to a scanning speed of the first scanning unit.

13. The method according to claim 12, characterized in that The speed of change of the reflection angle of the first optical element includes the rotation speed of the first optical element. In the first sampling period, the rotation speed of the first optical element is the same as the scanning speed of the first scanning unit, and the first optical element and the first scanning unit have opposite deflection directions of the light beam.

14. The method according to claim 12, characterized in that The speed of change of the reflection angle of the first optical element includes the rotation speed of the first optical element. In the first half of the first sampling period, the rotation speed of the first optical element is zero; in the second half of the first sampling period, the rotation speed of the first optical element is twice the scanning speed of the first scanning unit, and the first optical element and the first scanning unit have opposite deflection directions of the light beam.

15. The method according to claim 11, characterized in that The first optical element includes a rotatable lens, a first side of the rotatable lens includes a first plane, a second side of the rotatable lens includes a first curved surface, a curvature of the first curved surface at a first position changes linearly when the rotatable lens moves along a first axis, the first position includes an exit position when the light beam exits through the first curved surface, the first axis is perpendicular to the first plane, and determining the angle difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit includes: The movement speed of the rotatable lens along the first axis is determined according to the scanning speed of the first scanning unit.

16. The method according to claim 11, characterized in that The first steering angle and the second steering angle are generated by the first optical element through refraction, and determining the angle difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit includes: A speed of change of the refractive index of the first optical element is determined according to a scanning speed of the first unit.

17. The method according to any one of claims 11 to 16, characterized in that A second scanning unit is arranged between the first optical element and the first scanning unit. The second scanning unit is used to transmit the detection light beam emitted by the first optical element to the first scanning unit. The scanning speed of the first scanning unit is greater than the scanning speed of the second scanning unit.

18. The method according to any one of claims 11 to 17, characterized in that The light beam emitted by the emitting unit is a coherent light beam.

19. A control device, characterized in that: include: An acquisition unit, used for acquiring a scanning speed of the first scanning unit; A processing unit, used to: determine an angular difference between a first steering angle and a second steering angle according to a scanning speed of the first scanning unit, the first steering angle includes an angle between a first light beam and a first detection light beam at a first time point, the first detection light beam is a light beam emitted by the first light beam through a first optical element, the second steering angle includes an angle between a second light beam and a second detection light beam at a second time point, the second detection light beam is a light beam emitted by the second light beam through the first optical element, the first optical element is arranged between a transmitting unit and the first scanning unit, and the first light beam and the second light beam are emitted by the transmitting unit.

20. The control device according to claim 19, characterized in that The first steering angle is generated by reflection when the first optical element is at a first reflection angle, and the second steering angle is generated by reflection when the first optical element is at a second reflection angle, and the processing unit is used to: A change in the reflection angle of the first optical element is determined according to a scanning speed of the first scanning unit.

21. The control device according to claim 20, characterized in that: The speed of change of the reflection angle of the first optical element includes the rotation speed of the first optical element. In the first half of the first sampling period, the rotation speed of the first optical element is zero; in the second half of the first sampling period, the rotation speed of the first optical element is twice the scanning speed of the first scanning unit, and the first optical element and the first scanning unit have opposite deflection directions of the light beam.

22. The control device according to claim 20, characterized in that: The speed of change of the reflection angle of the first optical element includes the rotation speed of the first optical element. In the first half of the first sampling period, the rotation speed of the first optical element is zero; in the second half of the first sampling period, the rotation speed of the first optical element is twice the scanning speed of the first scanning unit, and the first optical element and the first scanning unit have opposite deflection directions of the light beam.

23. The control device according to claim 19, characterized in that The first optical element includes a rotatable lens, a first side of the rotatable lens includes a first plane, a second side of the rotatable lens includes a first curved surface, a curvature of the first curved surface at a first position changes linearly when the rotatable lens moves along a first axis, the first position includes an exit position when a light beam exits through the first curved surface, the first axis is perpendicular to the first plane, and the processing unit is used to: The movement speed of the rotatable lens along the first axis is determined according to the scanning speed of the first scanning unit.

24. The control device according to claim 19, characterized in that The first steering angle and the second steering angle are generated by the first optical element through refraction, and the processing unit is used for: A speed of change of the refractive index of the first optical element is determined according to a scanning speed of the first unit.

25. The control device according to claim 19, characterized in that A second scanning unit is arranged between the first optical element and the first scanning unit. The second scanning unit is used to transmit the detection light beam emitted by the first optical element to the first scanning unit. The scanning speed of the first scanning unit is greater than the scanning speed of the second scanning unit.

26. The control device according to claim 19, characterized in that The light beam emitted by the emitting unit is a coherent light beam.

27. A control device, characterized in that: include: Memory for storing computer programs; A processor, configured to execute the computer program stored in the memory, so that the apparatus performs the method according to any one of claims 11 to 18.

28. A detection system, characterized in that: It comprises an emitting unit, a first optical element, a first scanning unit and a control platform, wherein the control platform comprises the control device as claimed in any one of claims 19 to 27.

29. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed by a computer, the method according to any one of claims 11 to 18 is implemented.

30. A computer program product, characterized in that The computer program product comprises a computer program code, and when the computer program code is run on a computer, the method according to any one of claims 11 to 18 is executed.

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