Laser radar system, control method and control device

Abstract

The invention provides a laser radar system, a control method and a control device. The laser radar 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 the light beam emitted by the emitting unit so as to transmit the light beam emitted by the emitting unit to the first scanning unit. The deflection effect of the first optical element on the light beam is determined according to the scanning speed of the first scanning unit. The embodiment of the invention can be used for a detection or sensing system of a new energy vehicle or an intelligent driving vehicle, can compensate and reduce the influence of the scanning process of the scanning unit on light beam propagation, and can improve the speed and distance measurement performance of the laser radar.

Description

Technical Field

[0001] The present application relates to the field of detection technology, and more specifically, to a lidar system, a control method, and a control device. Background Art

[0002] Lasers are widely used in detection devices, such as lidar. The detection optical signal emitted by the lidar irradiates the target object and can generate a scattered optical signal after reflection. The system receives the reflected scattered optical signal and can obtain an intermediate-frequency current signal after beating with the local oscillator light. The intermediate-frequency current signal includes the time-delay information of the target, and the target distance can be inversely calculated therefrom. At the same time, if the target has a velocity in the laser pointing direction, it will also generate a Doppler frequency modulation on the backscattered optical signal, so that the final intermediate-frequency signal includes Doppler frequency information.

[0003] In the case of a lidar with a low channel, large-field imaging can be achieved by setting up a scanning mechanism. However, the scanning process will cause phenomena such as transceiver delay angle and scanning decoherence, which affect the speed measurement and distance measurement performance of the lidar. Therefore, how to ensure the speed measurement and distance measurement performance of the lidar in the case of using a scanning mechanism has become an urgent problem to be solved. Summary of the Invention

[0004] The present application provides a lidar system, a control method, and a control device, which can improve the speed measurement and distance measurement performance of the lidar in the case of using a scanning mechanism.

[0005] In a first aspect, a lidar system is provided. The lidar system may include a transmitting unit, a first optical element, and a first scanning unit. The first optical element is disposed between the transmitting unit and the first scanning mechanism. The transmitting unit is configured to emit 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 light beam; receive a second light beam at a second time point and output a second detection light beam. The angle between the first light beam and the first detection light beam is a first angle, and the angle between the second light beam and the second detection light beam is a second angle. The angular difference between the first angle and the second angle is determined according to the scanning speed of the first scanning mechanism.

[0006] Exemplarily, the light beam emitted by the emitting unit may be a pulsed light beam, or alternatively, a continuous wave light beam. The embodiments of the present application do not limit this. 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 that arrives at the first optical element at the first time point from the light beam emitted by the emitting unit. 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 light beam may be the outgoing light corresponding to the first light beam; correspondingly, the first light beam may be the outgoing light corresponding to the first detection light beam. Similarly, the second detection light beam may be the outgoing light corresponding to the second light beam, and correspondingly, the second light beam may be the incident light corresponding to the second detection light beam.

[0007] Exemplarily, the first optical element is disposed between the emitting 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 emitting 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 may be used to change the propagation path of the light beam emitted by the emitting unit. For example, the first optical element may change the propagation path of the light beam emitted by the emitting unit, and the first steering angle and the second steering angle may be generated by the deflection effect of the first optical element on the light beam.

[0008] In the traditional solution, for a low-channel lidar, a scanning mechanism may be adopted and the attitude of the scanning mechanism may be changed to scan the light beam, so as to achieve large field of view imaging. However, the scanning process will cause phenomena such as transceiver delay angle and scanning decoherence, which affect the speed measurement and ranging performance of the lidar. Exemplarily, taking the continuous wave lidar 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 a corresponding area on the surface of the target object along a preset trajectory. Correspondingly, the light spot formed when the detection light beam irradiates on the surface of the target object may be called a detection light spot, and the trajectory of the movement of the detection light spot may be called the scanning trajectory of the detection light spot (which may be simply referred to as the scanning trajectory).

[0009] On the one hand, in the actual scenario, the microscopic structure on the surface of the target object has undulations and is highly random. The microscopic structure will produce a certain degree of phase modulation on the detected optical signal. In the case of adopting a scanning mechanism (such as a scanning mirror), when the light beam emitted by the scanning mechanism irradiates different positions on the surface of the target object, the microscopic structures at different positions will produce different degrees of phase modulation, resulting in additional modulation of the spectrum of the intermediate frequency signal, that is, the so-called scanning decoherence phenomenon. In the traditional solution, it is difficult to know or eliminate the phase modulation caused by the microscopic structure during the scanning process.

[0010] On the other hand, when the scanning speed of the scanning mechanism is relatively fast, the position (or attitude) of the scanning mechanism will change between the moment when the detection beam exits the scanning mechanism and the moment when the return light of the detection beam returns to the scanning mechanism. This makes it difficult to align the target signal at the optical fiber or waveguide on the receiving side, namely the transceiver delay angle phenomenon. This transceiver delay angle will significantly deteriorate the signal intensity detected on the receiving side.

[0011] Exemplarily, in the lidar system provided by the present application, the first included angle and the second included angle are generated by the deflection effect of the first optical element on the beam, and the angle difference between the first included angle and the second included angle is determined according to the scanning speed of the first scanning unit. That is to say, compared with the traditional solution, in the lidar system provided by the present application, a first optical element capable of deflecting the beam is provided between the transmitting unit and the first scanning unit, and the deflection effect of the first optical element on the beam is determined according to the scanning speed of the first scanning unit. When the first scanning unit is in different attitudes during the scanning process, by controlling the deflection effect of the first optical element on the beam, taking a continuous wave radar as an example, the scanning trajectory of the detection spot can be adjusted, thereby improving the speed measurement and ranging performance of the lidar.

[0012] In one embodiment, during a sampling period, by controlling the deflection effect of the first optical element on the propagation direction of the beam according to the scanning speed of the first scanning unit, the same area on the surface of the target object can be scanned multiple times. That is to say, in the same scanning cycle, this area can be scanned multiple times along a preset scanning trajectory. By this means, the phase modulation effect of the microstructure of this area on the beam can be known, and further the influence of the scanning decoherence phenomenon on the lidar speed measurement and ranging performance can be reduced.

[0013] In another embodiment, during a sampling period, by controlling the deflection effect of the first optical element on the propagation direction of the beam according to the scanning speed of the first scanning unit, the moving distance of the detection spot on the surface of the target object within this sampling period can be shortened, the phase modulation caused by the scanning within this sampling period can be reduced, and the influence of the transceiver delay angle caused by the scanning on the lidar speed measurement and ranging performance can also be reduced.

[0014] In the present application, determining the deflection effect of the first optical element on the propagation direction of the beam according to the scanning speed of the first scanning unit can compensate for and reduce the influence of the scanning process of the scanning unit on the beam propagation, and can reduce the influence of the scanning unit on the lidar speed measurement and ranging performance.

[0015] In some possible implementation manners, the lidar system may further include a receiving unit, which can be used to receive the return light of the detection beam. For example, after the detection beam emitted by the first optical element is scanned by the scanning unit and reflected by the target object, the return light of the detection beam can be generated. The return light of the detection beam can be propagated to the receiving unit through the scanning unit and received by the receiving unit. Further, velocity measurement and distance measurement can be performed based on the return light of the detection beam and the local oscillator light of the beam emitted by the transmitting unit.

[0016] In combination with the first aspect, in some implementation manners of the first aspect, the first optical element can deflect the beam through reflection. For example, the first optical element can include an optical element such as a galvanometer mirror or a pendulum mirror that deflects the beam through reflection. Also, for example, by adjusting the postures of the galvanometer mirror and the pendulum mirror, the deflection effect on the propagation direction of the beam can be changed.

[0017] In combination with the first aspect, in some implementation manners of the first aspect, the first steering angle is generated through reflection when the first optical element is at the first reflection angle, and the second steering angle is generated through reflection when the first optical element is at the 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.

[0018] Exemplarily, in a scenario where the first optical element deflects the beam through reflection, when the position of the incident 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 beam will change, and the angle between the incident beam and the outgoing beam will change.

[0019] In a scenario where the first optical element deflects the beam in a manner of reflection, the deflection effect of the first optical element on the beam is associated with its posture. In this application, determining the change in the reflection angle of the first optical element according to the scanning speed of the first scanning unit can control the angle difference between the two without the need to measure the first steering angle and the second steering angle in real time, and can simplify the control of the deflection effect of the first optical element on the beam.

[0020] In combination with the first aspect, in some implementation manners of the first aspect, within 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 deflection directions of the first optical element and the first scanning unit for the beam are opposite.

[0021] Exemplarily, the first sampling period can be any sampling period. The first sampling period can include a first time point and a second time point.

[0022] In this application, the deflection of the beam by the first optical element can compensate for the deflection effect of the first scanning unit on the beam, which can shorten the moving distance of the detection spot on the surface of the target object within the sampling period, and can also reduce the degradation of the signal intensity on the receiving side caused by the attitude change of the first scanning unit, and can reduce the impact of scanning on the performance of laser velocity measurement and ranging.

[0023] Combined with the first aspect, in some implementation manners of the first aspect, in the first half period of the first sampling period, the rotation speed of the first optical element is zero; in the second half period 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 deflection directions of the first optical element and the first scanning unit on the beam are opposite.

[0024] In this application, within the same sampling period, through the deflection of the beam by the first optical element and the scanning effect of the first scanning unit on the beam, the same scanning trajectory can be reciprocally scanned, thereby the phase modulation result of the microstructure on the beam can be obtained, and the impact of scanning on the performance of laser velocity measurement and ranging can be reduced.

[0025] Combined with the first aspect, in some implementation manners of the first aspect, the first optical element can achieve the deflection of the beam through refraction. For example, the first optical element can include a rotatable lens, a photoelectric crystal, a magnetoelectric crystal, a thermoelectric crystal, a liquid crystal element, etc. Also, for example, by adjusting the refractive index of the photoelectric crystal, the deflection effect of the photoelectric crystal on the propagation direction of the beam can be changed.

[0026] Exemplarily, the refractive index everywhere inside the rotatable lens can be the same. By changing the shape and / or attitude of the rotatable lens, the deflection effect of the rotatable lens on the beam can be changed.

[0027] Combined with the first aspect, in some implementation manners of the first aspect, the first optical element includes a rotatable lens. The first side of the rotatable lens includes a first plane, and the second side of the rotatable lens includes a first curved surface. When the rotatable lens moves along the first axis, the curvature of the first curved surface at the first position changes linearly. The first position includes the exit position when the 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.

[0028] Exemplarily, the first plane and the first curved surface can be arranged oppositely along the first axis. The beam emitted by the emitting unit can be incident along the first plane and exit along the first curved surface. Correspondingly, when the rotatable lens rotates along the first axis, the curvature of the exit position of the beam on the first curved surface will change in a certain direction (such as the first direction). For example, it changes linearly along the first direction. The first direction can be the change direction of the exit position of the beam when the scanning lens moves.

[0029] In combination with the first aspect, in some implementations of the first aspect, the moving speed of the rotatable lens along the first axis is determined according to the scanning speed of the first scanning unit.

[0030] In one embodiment, the light beam emitted by the emitting unit is incident on the rotatable lens through the first plane, and correspondingly, exits from the first curved surface. Assuming that the incident light beam is parallel to the first axis, the curvature at the exit position of the first curved surface varies linearly in the first direction. For example, when the first scanning unit scans in a uniform speed scanning mode, the rotatable lens can be controlled to rotate uniformly along the first axis according to the scanning speed of the first scanning unit.

[0031] In this application, determining the moving speed of the rotatable lens along the first axis according to the scanning speed of the first scanning unit can control the angle difference between the two without the need to measure the first steering angle and the second steering angle in real time, and can simplify the control of the light beam deflection effect of the first optical element.

[0032] 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 thermoelectric crystal or a liquid crystal element, and the change in the refractive index of the first optical element is determined according to the scanning speed of the first scanning unit.

[0033] In this application, determining the change in the refractive index of the first optical element according to the scanning speed of the first scanning unit can control the angle difference between the two without the need to measure the first steering angle and the second steering angle in real time, and can simplify the control of the light beam deflection effect of the first optical element.

[0034] In combination with the first aspect, in some implementations of the first aspect, the system further includes a second scanning unit disposed between the first optical element and the first scanning unit. The second scanning unit is configured to transmit the light beam emitted from 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 that of the second scanning unit.

[0035] Exemplarily, a lidar system may include multiple scanning units to achieve scanning in multiple dimensions. Correspondingly, the scanning speeds of the multiple scanning units may be different. For example, a laser scanning system may include a fast scanning unit and a slow scanning unit. The first scanning unit may include the fast scanning unit, and the second scanning unit may include the slow scanning unit.

[0036] In combination with the first aspect, in some implementations of the first aspect, the light beam emitted by the emitting unit is a coherent light beam.

[0037] Second aspect, a control method is provided, which can be executed by a lidar system, or can be executed by an intelligent driving device provided with the lidar system, or can be executed by a chip or a processor corresponding to the lidar system. In some possible implementation manners, the chip or the processor corresponding to the lidar system can be disposed in the radar, or can also be disposed outside the radar.

[0038] The method includes: obtaining the scanning speed of the first scanning unit; determining the angular difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit, where the first steering angle includes the included angle between the first light beam and the first detection light beam at the first time point, the first detection light beam is the light beam emitted from the first light beam through the first optical element, the second steering angle includes the included angle between the second light beam and the second detection light beam at the second time point, the second detection light beam is the light beam emitted from the second light beam through the first optical element, the first optical element is disposed between the transmitting unit and the first scanning unit, and the first light beam and the second light beam are emitted by the transmitting unit.

[0039] In combination with the second aspect, in some implementation manners 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 according to the scanning speed of the first scanning unit may include: determining the change in the reflection angle of the first optical element according to the scanning speed of the first scanning unit.

[0040] In combination with the second aspect, in some implementation manners of the second aspect, the speed of change of the reflection angle of the first optical element includes the rotation speed of the first optical element. 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 deflection directions of the first optical element and the first scanning unit for the light beam are opposite.

[0041] In combination with the second aspect, in some implementation manners of the second aspect, 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 period of the first sampling period, the rotation speed of the first optical element is zero; in the second half period 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 deflection directions of the first optical element and the first scanning unit for the light beam are opposite.

[0042] In combination with the second aspect, in certain implementations of the second aspect, the first optical element includes a rotatable lens. The first side of the rotatable lens includes a first plane, and the second side of the rotatable lens includes a first curved surface. When the rotatable lens moves along the first axis, the curvature of the first curved surface changes linearly at the first position. 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. Determining the angular difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit may include: determining the moving speed of the rotatable lens along the first axis according to the scanning speed of the first scanning unit.

[0043] In combination with the second aspect, in certain implementations of the second aspect, the first steering angle and the second steering angle are generated by the refraction of the first optical element. Determining the angular difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit may include: determining the change speed of the refractive index of the first optical element according to the scanning speed of the first unit.

[0044] In combination with the second aspect, in certain implementations of the second aspect, a second scanning unit is provided between the first optical element and the first scanning unit. The light beam exiting from the first optical element through the coherent light beam is transmitted to the first scanning unit through the second scanning unit. The scanning speed of the first scanning unit is greater than the scanning speed of the second scanning unit.

[0045] In combination with the second aspect, in certain implementations of the second aspect, the light beam emitted by the emitting unit may include a coherent light beam.

[0046] In combination with the second aspect, in certain 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 thermoelectric crystal, or a liquid crystal element.

[0047] In a third aspect, a control device is provided. The control device may include: an acquisition unit for acquiring the scanning speed of the first scanning unit; a processing unit for: determining the angular difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit. The first steering angle includes the included angle between the first light beam and the first detection light beam at the first time point. The first detection light beam is the light beam exiting from the first optical element through the first light beam. The second steering angle includes the included angle between the second light beam and the second detection light beam at the second time point. The second detection light beam is the light beam exiting from the first optical element through the second light beam. The first optical element is disposed between the emitting unit and the first scanning unit. The first light beam and the second light beam are emitted by the emitting unit.

[0048] In combination with the third aspect, in some implementation manners 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 can be configured to: determine the change in the reflection angle of the first optical element according to the scanning speed of the first scanning unit.

[0049] In combination with the third aspect, in some implementation manners of the third aspect, the speed of the change in the reflection angle of the first optical element includes the rotation speed of the first optical element. In the first half period of the first sampling period, the rotation speed of the first optical element is zero; in the second half period 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 deflection directions of the first optical element and the first scanning unit for the light beam are opposite.

[0050] In combination with the third aspect, in some implementation manners of the third aspect, the speed of the change in the reflection angle of the first optical element includes the rotation speed of the first optical element. In the first half period of the first sampling period, the rotation speed of the first optical element is zero; in the second half period 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 deflection directions of the first optical element and the first scanning unit for the light beam are opposite.

[0051] In combination with the third aspect, in some implementation manners of the third aspect, the first optical element includes a rotatable lens. The first side of the rotatable lens includes a first plane, and the second side of the rotatable lens includes a first curved surface. When the rotatable lens moves along the first axis, the curvature of the first curved surface at the first position changes linearly. 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. The processing unit can be configured to: determine the moving speed of the rotatable lens along the first axis according to the scanning speed of the first scanning unit.

[0052] In combination with the third aspect, in some implementation manners of the third aspect, the first steering angle and the second steering angle are generated by the refraction of the first optical element. The processing unit can be configured to: determine the change speed of the refractive index of the first optical element according to the scanning speed of the first unit.

[0053] In combination with the third aspect, in some implementation manners of the third aspect, a second scanning unit is disposed between the first optical element and the first scanning unit. The light beam emitted from the first optical element by the coherent light beam is transmitted to the first scanning unit through the second scanning unit. The scanning speed of the first scanning unit is greater than the scanning speed of the second scanning unit.

[0054] In combination with the third aspect, in some implementation manners of the third aspect, the light beam emitted by the emitting unit can include a coherent light beam.

[0055] Fourthly, 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 executes the method in the first aspect and any possible implementation manner thereof as described above.

[0056] Fifthly, a detection system is provided, which includes: a transmitting unit, a first optical element, a first scanning unit, and a control platform, and the control platform includes the device in the third aspect or the fourth aspect and any possible implementation manner thereof as described above.

[0057] Sixthly, a computer program product is provided, and the computer program product includes: computer program code, which, when running on a computer, causes the computer to execute the method in the second aspect and any possible implementation manner thereof as described above.

[0058] Seventhly, a computer-readable storage medium is provided, and the computer-readable medium stores a computer program, which, when running on a computer, causes the computer to execute the method in the second aspect and any possible implementation manner thereof as described above.

[0059] Eighthly, a chip is provided, and the chip includes a circuit for executing the method in the second aspect and any possible implementation manner thereof as described above.

[0060] Ninthly, an intelligent driving device is provided, and the intelligent driving device includes the device in the third aspect or the fourth aspect and any possible implementation manner thereof, or includes the system in the fifth aspect and any possible implementation manner thereof as described above.

[0061] Exemplarily, the intelligent driving device may include a vehicle. Description of the Drawings

[0062] Figure 1 is a schematic diagram of the time-frequency characteristics of a frequency-modulated continuous wave provided by an embodiment of the present application;

[0063] Figure 2 is a schematic diagram of a detection scenario provided by an embodiment of the present application;

[0064] Figure 3 is a schematic diagram of another detection scenario provided by an embodiment of the present application;

[0065] Figure 4 is a schematic diagram of another detection scenario provided by an embodiment of the present application;

[0066] Figure 5 is a schematic diagram of a system architecture provided by an embodiment of the present application;

[0067] Figure 6It is a schematic flowchart of a control method provided by an embodiment of the present application;

[0068] Figure 7 It is a schematic diagram of another detection scenario provided by an embodiment of the present application;

[0069] Figure 8 It is a schematic diagram of another detection scenario provided by an embodiment of the present application;

[0070] Figure 9 It is a schematic diagram of the scanning trajectory of a detection light spot provided by an embodiment of the present application;

[0071] Figure 10 It is a schematic diagram of the scanning trajectory of another detection light spot provided by an embodiment of the present application;

[0072] Figure 11 It is a schematic diagram of another detection scenario provided by an embodiment of the present application;

[0073] Figure 12 It is a schematic diagram of another detection scenario provided by an embodiment of the present application;

[0074] Figure 13 It is a schematic block diagram of a control device provided by an embodiment of the present application;

[0075] Figure 14 It is a schematic block diagram of another control device provided by an embodiment of the present application. Detailed implementation manners

[0076] Next, the technical solutions in the present application will be described with reference to the accompanying drawings.

[0077] Exemplarily, according to the form of the emitted detection signal, a radar can be classified into a pulsed radar and a continuous wave radar. A pulsed radar can detect surrounding target objects through high-frequency pulsed signals. A continuous wave radar can include a single-frequency continuous wave radar, a multi-frequency continuous wave radar, a frequency-modulated continuous wave radar, etc. A frequency-modulated continuous wave (FMCW) radar can detect the distance and speed of surrounding objects by sending FMCW signals with relatively low-cost equipment. The frequency modulation method can include triangular wave modulation, sawtooth wave modulation, etc., and an FMCW signal with frequency varying with time can be obtained through frequency modulation. For a lidar, the detection signal is an optical signal, which can also be called a detection beam.

[0078] 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 (which can also be called an intermediate-frequency signal) can be obtained through beat frequency. This intermediate-frequency signal can include the time-delay information of the target object, and thus the distance of the target can be obtained. When the target object has a velocity in the direction pointed to by the detection signal (which can also be called the 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. Taking the following triangular wave modulation as an example, in combination with Figure 1 the FMCW radar will be described.

[0079] Exemplarily, Figure 1 is a schematic diagram of the time-frequency characteristics of a frequency-modulated continuous wave provided by 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 as Figure 1 shown. 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 velocity information of the target. By performing beat frequency on the local oscillator signal and the return signal, a beat frequency signal can be obtained.

[0080] Let R represent the relative distance between the target object and the lidar, v represent the relative velocity between the target object and the lidar, and f1 and f2 respectively represent the maximum and minimum values of the beat frequency signal in the frequency domain. The distance and velocity of the target object relative to the lidar can satisfy the following relationships: R ∝ (f1 + f2), v ∝ (f1 - f2).

[0081] For lidars, adopting a coherent detection mechanism of continuous waves may cause problems such as speckle, scanning decoherence, and transceiver delay angle.

[0082] 1. Speckle effect:

[0083] There is inevitably roughness on the surface of the target object, that is, there are inevitably height fluctuations in its surface microstructure. Each point on the rough surface can be understood as a combination of countless points or surface sources. When the detection beam emitted by the lidar irradiates the rough surface of the target object, for each point or surface source on the rough surface, the incident light can be reflected or transmitted, and the reflected light or transmitted light from different points has different phases. Due to the huge number and independence of the points or surface sources from each other, the reflected light or transmitted light changes violently and irregularly in terms of intensity with spatial variation.

[0084] When the spot emitted by the lidar irradiates the target surface, affected by the microscopic structure of the target surface, within a single spot, the backscattered light generated by the spot micro-elements at different positions will have different time delays, manifested as different degrees of phase modulation of the backscattered light, thus causing wavefront distortion of the backscattered light. Due to the strong randomness of the height fluctuations on the surface of the target object, the phase of the backscattered light is correspondingly randomly modulated, manifested as the coherent superposition between the spot micro-elements of the backscattered light within the receiving field of view. And because the modulation received by the phase of each spot micro-element is random, there is coherent enhancement at some positions and coherent cancellation at some positions, finally presenting as bright and dark spots, namely the so-called speckles. When the wavelength of the detection light is on the same order of magnitude as the microscopic height fluctuations on the surface of the target object, the speckle effect is particularly obvious.

[0085] After the system receives this speckle, by performing beat frequency with the local oscillator light, an intermediate frequency signal can be obtained. This intermediate frequency signal can satisfy:

[0086] I(t) = Aexp[j(ω(t) + θ)] = ΣE0(x, y; t) E s(x, y; t)

[0087] where x, 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. E o (x, y; t) represents the complex amplitude of the light at different positions within the spot of the local oscillator signal (simply referred to as the local oscillator spot), and E s (x, y; t) represents the complex amplitude of the light at different positions within the spot of the return signal (simply referred to as the return spot). Due to the modulation of the return spot by the rough surface of the target object, compared with the spot of the detection signal (simply referred to as the detection spot), both the amplitude and phase of the return spot change and cannot completely coherently enhance with the local oscillator spot to produce ideal coherent detection. Therefore, both the amplitude A and the initial phase θ in the intermediate frequency signal are associated with the surface characteristics of the target object. Generally speaking, the amplitude A of the intermediate frequency signal will be lower than the ideal amplitude, resulting in a lower signal-to-noise ratio of the actual return signal than that of the ideal return signal.

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

[0089] 2. Scanning decoherence

[0090] Due to the influence of the surface characteristics of the target object on the intermediate frequency signal, when the detection spot quickly scans across the surface of the target object, the intermediate frequency signals corresponding to different sampling time points will change.

[0091] Exemplarily, Figure 2 is a schematic diagram of a detection scenario provided by an embodiment of the present application. At a certain moment, the detection beam irradiates the surface of the target object, forming a detection light spot. As Figure 2 shown by the boundary of the light spot, it can be understood as the boundary of the light beam corresponding to the light spot during propagation.

[0092] At different sampling times, the detection light 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(m(n) + θ n )]. Wherein, A n and θ n can represent the amplitude and initial phase of the intermediate-frequency signal corresponding to the nth sampling time point, and n is a positive integer.

[0093] In an ideal scenario, as the scanning progresses, the detection light spot moves on the surface of the target object, and A n and θ n of the intermediate-frequency signal do not change with the sampling time. However, due to the phase modulation of the light beam by the microstructure, in the actual scenario, A n and θ n of the intermediate-frequency signal change with different sampling times. And the change of the phase θ n with the sampling time may cause additional phase modulation to the intermediate-frequency signal, that is, the so-called scanning decoherence. The change of the phase with the sampling time point will cause an additional change in the spectrum of the intermediate-frequency signal, and the change of the spectrum will affect the speed measurement and ranging performance of the lidar.

[0094] 3. Transceiver delay angle

[0095] In a scenario with a scanning mechanism, the detection light emitted by the lidar is irradiated onto the target object through the scanning mechanism. As the scanning progresses, the detection beam can irradiate different positions on the surface of the target object. The scattered light reflected from the surface of the target object is received by the detection system through the scanning mechanism. The detection system may include a receiving surface element, and the receiving surface element may refer to the area where the photodiodes in the sensor are distributed. The light spot can be made to fall entirely inside the receiving surface element through means such as a diaphragm or a lens to achieve the reception of the scattered light.

[0096] Due to the different relative distances between different target objects and the radar, correspondingly, there will be differences in the time delay of the return signal relative to the detection signal. At different time delays, the angles of rotation of the scanning mechanism may be different, that is, the so-called transceiver delay angles will be different. This will cause the center of the light spot to deviate to different degrees on the equivalent receiving surface element. When the relative distance between the target object and the radar is different, the deviation amount is also different.

[0097] Exemplarily, Figure 3 is a schematic diagram of another detection scenario provided by an embodiment of the present application. As Figure 3 shown, 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 through 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 can be acquired by the receiving unit through the scanning mechanism.

[0098] In one embodiment, as Figure 3 shown, taking the target 2 as an example, in a sampling period, when the light beam emitted by the transmitting unit exits the scanning mechanism, the scanning mechanism is in the posture M. When the reflected light reflected by the target 2 enters the scanning mechanism, the scanning mechanism may be in the posture N. That is to say, between the moment when the detection light beam exits the scanning mechanism and the moment when the return light enters the scanning mechanism, the posture of the scanning mechanism may change due to its actuation.

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

[0100] When the scanning speed of the scanning mechanism is relatively high, in a sampling period, when the angle turned by the scanning mechanism is relatively large (for example, the gap between the postures M and N is relatively large), it may cause the offset of the return light spot on the receiving surface element to be on the order of micrometers. That is to say, on the equivalent receiving surface element of the optical fiber or waveguide on the receiving side, there is an offset on the order of micrometers. Correspondingly, the deviation of the relative distance between the target object and the radar may reach the order of dozens of meters or even hundreds of meters. This deviation seriously affects 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 transceiver delay angle by means of pre-bias. For coherent detection, it is also impossible to simply compensate for the transceiver delay angle 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 the local oscillator light, which will cause a significant increase in the shot noise of the system, thereby reducing the signal-to-noise ratio of the return signal. On the other hand, using multimode fiber to couple the return signal will have a decoherence effect between different modes, also resulting in a reduction in the detection efficiency.

[0102] It should be noted that Figure 3 the description of the detection system in [] is only an example, and the specific structure of the detection system in the embodiments of the present application is not limited. For example, in some possible implementation manners, the receiving unit may be coupled to the transmitting unit. Another example is that Figure 3 different from the manner shown in [], in some possible implementation manners, the receiving unit and the transmitting unit may be coaxially arranged. Another example is that in some possible implementation manners, the scanning mechanism may include multiple scanning units to achieve multi-dimensional scanning. The scanning unit may include a galvanometer, a swinging mirror, a rotating mirror, etc.

[0103] Exemplarily, Figure 4 is a schematic diagram of another detection scenario provided by the embodiments of the present application. Figure 4 shows the scanning manner of the detection system 200, where the setting manner of the receiving unit ( Figure 4 not shown) of the detection system 200 may be similar to that of the detection system 100.

[0104] As Figure 4 shown in (a) of [], in the detection system 200 shown in Figure 4 the scanning mechanism may include a scanning mirror 1 and a scanning mirror 2. The scanning mirror 1 and the scanning mirror 2 can be respectively understood as a scanning unit. Correspondingly, the light beam emitted by the transmitting unit can be irradiated onto 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 orthogonally arranged. By rotating the scanning mirror 1 and the scanning mirror 2, multi-dimensional scanning can be achieved.

[0105] In some possible implementation manners, the scanning mirror 1 can be implemented by a galvanometer, and the rotation of the scanning mirror 1 can be achieved by a stepping motor. The scanning mirror 2 can be implemented by a rotating mirror, and its scanning manner can be continuous scanning. In some possible implementation manners, the scanning mirror 1 and / or the scanning mirror 2 can also be implemented by other means, and the embodiments of the present application do not limit this.

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

[0107] In one embodiment, the scanning speed of the scanning mirror 2 can be much greater than that of the scanning mirror 1. That is, a combination of slow scanning and fast scanning is adopted. Correspondingly, the scanning mirror 1 can correspond to the fast scanning unit, and the scanning mirror 2 can correspond to the slow scanning unit. The scanning mirror 1 can also be called the slow scanning mirror, and the scanning mirror 2 can also be called the fast scanning mirror. For example, when the slow scanning mirror is in the attitude A, since the rotation speed of the fast scanning mirror is much greater than that of the slow scanning mirror, when the attitude of the fast scanning mirror changes from the attitude 1 to the attitude 2, it can be considered that the attitude of the slow scanning mirror does not change. Correspondingly, the detection spot sweeps across the surface of the target object along the scanning direction 1. For another example, when the slow scanning mirror rotates to the attitude B, the fast scanning mirror can rotate again from the attitude 1 to the attitude 2 along the rotation direction 2, so as to realize the scanning of multiple dimensions of the target. For another example, when the scanning mirror 1 is in the attitude A and the scanning mirror 2 is in the attitude 1, and when the scanning mirror 1 is in the attitude A and the scanning mirror 2 is in the attitude 2, they can respectively correspond to the scanning mechanism in the system 100 being in the attitude M and the attitude N. Similarly, the system 200 will have problems of transceiver delay angle and scanning decoherence.

[0108] As described above, when the lidar detects the distance and speed of the target object by scanning, there will inevitably be problems of scanning decoherence and transceiver delay angle, resulting in additional phase modulation and a decrease in the signal-to-noise ratio of the returned signal, thus seriously affecting the ranging and speed measurement performance of the system.

[0109] In view of this, the embodiments of the present application provide a control method and a control device. Through the deflection effect of the first optical element on the light beam propagation direction, it is possible to compensate for and reduce the influence of the scanning process of the scanning unit on the light beam propagation, and reduce the influence of the scanning unit on the laser speed measurement and ranging performance.

[0110] Exemplarily, Figure 5 is a schematic diagram of a system architecture provided by the embodiments of the present application. As shown in Figure 5As shown, 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, and 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] Exemplarily, the transmitting unit 310 can be used to emit 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 the first light beam at the first time point and emit a first detection light beam; receive the second light beam at the second time point and output a second detection light beam. The angle between the first light beam and the first detection light beam is the first angle, and the angle between the second light beam and the second detection light beam is the second angle. The angular difference between the first angle and the second angle is determined according to 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 can be any time points. The first light beam can include the light beam emitted by the transmitting unit 310 at the first time point, or the light beam that reaches the first optical element 330 at the first time point from the light beam emitted by the transmitting unit 310. Similarly, the second light beam can include the light beam emitted by the transmitting unit 310 at the second time point, or the light beam that reaches the first optical element 330 at the second time point from the light beam emitted by the transmitting unit 310. For the first optical element, the first detection light beam can be the outgoing light corresponding to the first light beam; correspondingly, the first light beam can be the incoming light corresponding to the first detection light beam. Similarly, the second detection light beam can be the outgoing light corresponding to the second light beam, and correspondingly, the second light beam can be the incoming light corresponding to the second detection light beam.

[0113] In some possible implementation manners, 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 mirror or a pendulum mirror that deflects the light beam through reflection. Also, for example, by adjusting the attitude of the galvanometer mirror or the pendulum mirror, the deflection effect on the propagation direction of the light beam can be changed.

[0114] In some possible implementation manners, the first optical element 330 can deflect a light beam through refraction. For example, the first optical element can include a lens, a photoelectric crystal, a magnetoelectric crystal, a thermoelectric crystal, a liquid crystal element, etc. For another example, by adjusting the attitude of the lens, the propagation path of the light beam in the lens can be changed to meet the requirements for the deflection effect of the light beam in different scenarios. For another example, by adjusting the refractive index of the photoelectric crystal, the deflection effect on the propagation direction of the light beam can be changed.

[0115] In some possible implementation manners, the system 300 may further include a receiving unit 340. The light beam emitted by the transmitting unit 310 is irradiated to the first scanning unit 320 after passing through the first optical element 330, and after passing through the first scanning unit 320, it can be irradiated to the surface of the target object. The return light of the detection light beam generated by reflection from the target object can be received by the receiving unit 340 through the first scanning unit 320. The receiving unit 340 may be coaxially arranged with the transmitting unit 310 or may not be coaxially arranged, and the present application does not make a limitation on this.

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

[0117] In some possible implementation manners, the first optical element can be disposed between the first scanning unit 320 and the transmitting unit 310 and is also between the first scanning unit 320 and the receiving unit 340. That is to say, the first optical element can be disposed on the propagation path of the light beam emitted by the transmitting unit and is also disposed on the propagation path of the return light.

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

[0119] Exemplarily, the first scanning unit 320 can be disposed in a scanning mechanism. The first optical element 330 can be independent of the scanning mechanism or can also be coupled to the scanning mechanism, and the embodiments of the present application do not make a limitation on this.

[0120] In some possible implementations, the scanning mechanism may include a plurality of scanning units including a first scanning unit 320 to implement scanning in multiple directions. Exemplarily, the system 300 may further include a second scanning unit 350, and the second scanning unit 350 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 from the first optical element 330 to the first scanning unit 320. The scanning speed of the second scanning unit 350 is less than that of the first scanning unit. For example, the scanning directions of the second scanning unit 350 and the first scanning unit 320 may be orthogonally arranged to implement scanning in two directions. For another example, by changing the propagation direction of the light beam, the second scanning unit 350 may transmit the light beam emitted from the first optical element 330 to the first scanning unit 350. For another example, the second scanning unit 350 includes a slow scanning unit, and the first scanning unit 320 includes 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] Exemplarily, Figure 6 It is a schematic flowchart of a control method provided by an embodiment of the present application. The method 400 may be executed by a lidar system, or may be executed by an intelligent driving device provided with the lidar system, or may be executed by a control device corresponding to the lidar system, or may be executed by a chip or a processor in the control device. The control device corresponding to the lidar system may be coupled to the system or may be independent of the system. The method 400 may include:

[0122] S410, obtain the scanning speed of the first scanning unit.

[0123] Exemplarily, scanning of the light beam from the first optical element may be achieved by changing the attitude of the first scanning unit. For example, at a first time point and a second time point, the attitudes of the first scanning unit 320 may be a first scanning attitude and a second scanning attitude, respectively. The first scanning unit 320 will have different deflecting effects on the light beam in different scanning attitudes. That is to say, the included 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 attitude of the first scanning unit 320. The change of this included angle between different moments is determined by the change of the scanning attitude 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 uniform speed. The change in the attitude of the first scanning unit 320 between these 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 two given time points, the change in the attitude of the first scanning unit 320 between these two time points is determined by the scanning speed of the first scanning unit 330 between these two time points.

[0126] In some possible implementation manners, the scanning speed of the first scanning unit 320 can be determined by obtaining the attitudes of the first scanning unit 320 at multiple time points.

[0127] S420. Determine the angle difference between the first steering angle and the second steering angle 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 light beam at the first time point. The first detection light beam is the light beam emitted from the first light beam through the first optical element. The second steering angle includes the angle between the second light beam and the second detection light beam at the second time point. The second detection light beam is the light beam emitted from the second light beam through the first optical element. The first optical element is disposed between the emitting unit and the first scanning unit. The first light beam and the second light beam are emitted by the emitting unit.

[0128] Exemplarily, the first time point, the second time point, the first steering angle, and the second steering angle can refer to the description in the system architecture 300.

[0129] In some possible implementation manners, 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 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] Exemplarily, in a scenario where the first optical element 330 deflects the light beam by reflection, the deflection effect of the light beam can be adjusted by adjusting the reflection angle (or the attitude) of the first optical element 330. Similarly, in a scenario where the first optical element 330 deflects the light beam by refraction, the propagation path of the light beam in the lens can be adjusted by adjusting the attitude of the first optical element 330 to achieve the adjustment of the light beam deflection effect.

[0131] In one embodiment, it is assumed that the propagation path of the light beam emitted by the transmitting unit 310 remains unchanged before reaching the first optical element 330. When the first optical element 330 is at different reflection angles, the light beam will exit 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 exiting light beam depends on the change in the reflection angle of the first optical element 330. That is to say, according to the reflection angle (or posture) of the first optical element 330, its deflection effect on the light beam can be determined, such as the first steering angle and the second steering angle. That is to say, 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 points. The change in the posture of the first optical element 330 between the corresponding time points is determined by the moving speed of the first optical element 330.

[0132] Exemplarily, in a scenario where the deflection effect of the first optical element 330 on the light beam is adjusted by adjusting the posture of the first optical element 330, determining the angular difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit 320 may include: determining the moving speed of the first optical unit 330 according to the scanning speed of the first scanning unit 320. For example, according to the moving speed of the first optical unit 330, the change in the posture of the first optical element 330 between the corresponding time points can be determined, and correspondingly, the change in the deflection effect of the first optical element 330 on the light beam between the corresponding time points can be determined.

[0133] In one embodiment, within 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 deflection directions of the first optical element 330 and the first scanning unit 320 on the light beam are opposite. 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 yet another embodiment, in the first half period of the first sampling period, the rotation speed of the first optical element 330 is zero; in the second half period 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 deflection directions of the first optical element 330 and the first scanning unit 320 on the light beam are opposite.

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

[0136] In some possible implementation manners, in a scenario where the first optical element 330 deflects a light beam through refraction, the refractive index of the first optical element 330 can be controlled to control the light beam deflection effect. For example, assuming that the first optical element 330 includes a photoelectric crystal, the change in the refractive index of the photoelectric crystal is 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 implementation manners, a second scanning unit is disposed between the first optical element 330 and the first scanning unit 320, and the second scanning unit can transmit the light beam emitted from the first optical element 330 to the first scanning unit 320.

[0138] The following Figures 7 to 12 briefly introduces the working mode of the detection system involved in the embodiments of the present application. Figures 7 to 12 The system involved in

[0139] Exemplarily, Figure 7 is a schematic diagram of a detection scenario provided by an embodiment of the present application. As Figure 7 shown, the system 500 may include a transmitting unit, a first optical element, a scanning mirror 1, and a scanning mirror 2. The scanning mirror 1 in the system 500 may correspond to the second scanning unit 350 in the system 300, and the scanning mirror 2 may correspond to the first scanning unit 320. The system 500 can be understood as an extension or deformation of the system 300, and can also be understood as adding a first optical element on the basis of the system 200.

[0140] In one embodiment, when the scanning mirror 1 is in the attitude A and the scanning mirror 2 is in the attitude 1, the boundary of the propagation path of the light beam emitted by the transmitting unit can be the spot boundary #1. In the case where the first optical element is not provided (taking the system 200 as an example), when the scanning mirror 1 is in the attitude A and the scanning mirror 2 is in the attitude 2, the boundary of the propagation path of the light beam emitted by the transmitting unit can be the spot boundary #2, as Figure 4 shown in (a) of Figure 7 In the case where the first optical element is provided, according to the scanning speed of the scanning mirror 2, by adjusting the light beam deflection effect of the first optical element, when the scanning mirror 1 is in the attitude A and the scanning mirror 2 is in the attitude 2, the boundary of the propagation path of the light beam can be the spot boundary #3, as

[0141] shown in Figure 8 In some possible implementation manners, the first optical element may include a galvanometer mirror. For example, as Figure 8This is a schematic diagram of a detection scenario provided by an embodiment of the present application. As Figure 8 shown, the system 600 can be understood as a deformation or extension of the systems 300 and 500, and the scanning mirror 3 in the system 600 can correspond to the first optical element in the systems 300 and 500.

[0142] Exemplarily, in the system 600, the rotation direction 1 and the rotation direction 2 can be orthogonally arranged. The rotation direction 1 and the rotation direction 3 can be orthogonally arranged. Assuming that the scanning mirror 2 is a continuous rotating mirror and the scanning mirror 3 is a galvanometer mirror or a pendulum mirror, the scanning mirror 3 can change the propagation direction of the light beam through reflection. Assuming that the scanning speed of the scanning mirror 1 is much smaller than the scanning speed of the scanning mirror 2, the rotation of the scanning mirror 1 can be ignored in one sampling period.

[0143] In one embodiment, in the same sampling period, the rotation speeds of the scanning mirror 2 and the scanning mirror 3 can be the same, but their rotation directions can be opposite. For example, the rotation direction 2 is clockwise and the rotation direction 3 is counterclockwise; or, the rotation direction 2 is counterclockwise and the rotation direction 3 is clockwise.

[0144] As Figure 8 shown, 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 light beam pointing caused by the scanning of the scanning mirror 2 can be compensated by controlling the rotation of the scanning mirror 3. After the end of this sampling period, the scanning mirror 3 can be controlled to return to its initial state. In the next sampling period, the scanning mirror 2 and the scanning mirror 3 can be controlled to rotate as in the previous sampling period, so that in this sampling period, the change in the light beam pointing caused by the scanning mirror 2 can be compensated by controlling the rotation of the scanning mirror 3. Repeating this process, the pointing of the light beam emitted by the scanning mechanism can be controlled. The scanning trajectory of the detection light spot in this scenario will be introduced below in combination with Figure 9 the following.

[0145] As Figure 9 shown, in the case where the scanning mirror 3 is not provided or the scanning mirror 3 does not act, when the scanning mirror 2 rotates, the scanning trajectory formed by the light beam emitted by the scanning mirror 2 irradiating the target object can be the scanning trajectory 1. In the case where the rotation speed of the scanning mirror 3 is the same as that of the scanning mirror 2 but their rotation directions are opposite, in one sampling period, the pointing of the light beam emitted by the scanning mirror 2 may not change with the rotation of the scanning mirror 2. Due to the relative position between the scanning mirror 2 and the scanning mirror 3, within one scanning period, the light beam emitted by the scanning mirror 2 may have a translation in the scanning direction. For example, as Figure 8 shown, as the scanning mirror 2 changes from attitude 1 to attitude 2, by controlling the rotation of the scanning mirror 3, the light spot boundary moves from the light spot boundary #1 to the light spot boundary #3. Correspondingly, the scanning trajectory of the detection light spot can be the scanning trajectory 2, asFigure 9 As shown, by adjusting the relative positions between the scanning mirror 2 and the scanning mirror 3, this translation amount can be compressed.

[0146] In the embodiments of the present application, by controlling the rotation of the scanning mirror 3, the length of the scanning trajectory of the detection light spot on the surface of the target object can be reduced, thereby suppressing the scanning decoherence caused by the scanning mechanism. Moreover, since the direction of the detection light emitted by the scanning mirror 2 remains unchanged within the same sampling period, the problem of the reduction in the return signal power caused by the transceiver delay angle can be greatly improved, the signal-to-noise ratio of the return signal can be increased, and the ranging and velocity measurement performance of the lidar can be improved.

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

[0148] As Figure 10 shown, in the case where the scanning mirror 3 is not provided or the scanning mirror 3 does not operate, when the scanning mirror 2 rotates, the scanning trajectory formed by the light beam emitted by the scanning mirror 2 irradiating the target object can be the scanning trajectory 1. When the scanning mirror 3 does not rotate in the first half of the sampling period and rotates in the second half of the sampling period in the opposite direction to the scanning mirror 2 at twice the speed of the scanning mirror 2, the scanning trajectory formed by the light beam emitted by the scanning mirror 2 irradiating the target object can be the scanning trajectory 3. That is to say, within a sampling period, the detection light spot can perform two scans in opposite directions on the surface of the target object along the same scanning trajectory.

[0149] In the embodiments of the present application, when receiving the return signal of this sampling period, the scanning decoherence effect of the second scan can be compensated by extracting the phase modulation information obtained from the first scan. The phase modulation effect of the microstructure on the light beam can be known, the influence of the scan on the ranging and velocity measurement performance of the laser can be reduced, and the ranging and velocity measurement performance of the lidar can be improved.

[0150] In some possible implementation manners, the scanning mirror 1, the scanning mirror 2, and the scanning mirror 3 can be coupled to the same scanning mechanism.

[0151] In some possible implementation manners, the light beam direction adjustment mechanism can include a lens. For example, as Figure 11 shown, Figure 11 is a schematic diagram of another detection scenario provided by the embodiments of the present application. As Figure 11As shown, 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] Exemplarily, in system 700, when lens 1 rotates in the rotation direction 4, the deflection effect of lens 1 on the light beam will change. For example, as shown in (a) of Figure 11 , ignoring the rotation of scanning mirror 1, when scanning mirror 2 rotates from attitude 1 to attitude 2, by controlling lens 1 to rotate to the corresponding attitude along rotation axis 1, the boundary of the light beam on its propagation path can be changed from light spot boundary #1 to light spot boundary #3.

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

[0154] As Figure 11 shown in (b) of Figure 11 , when lens 1 rotates along rotation axis 1, the light beam emitted from the emitting unit can irradiate different positions on surface 1, and correspondingly, it exits from different positions on surface 2. Figure 11 The dotted line shown in (b) of Figure 11 can represent the exit position of the light beam on surface 2 during the rotation of lens 1 along rotation axis 1. For example, the curvature of surface 2 can linearly change along the dotted line shown in (b) of Figure 11 , so that when lens 1 rotates, the angle between the first incident light and the first exit light can linearly change. Also, for example, by controlling the rotation speed of lens 1 according to the rotation speed of 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 implementation manners, the first optical element may include an electro-optic crystal. For example, as Figure 12 shown, Figure 12 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-optic crystal in system 800 can correspond to the first optical element in systems 300 and 500.

[0156] Exemplarily, in system 800, the electro-optic crystal may be inclined with respect to the light beam emitted from the emitting unit. In system 800, by adjusting the refractive index of the electro-optic crystal, the deflection effect of the electro-optic crystal on the light beam can be adjusted. For example, by controlling the refractive index of the electro-optic crystal according to the rotation speed of scanning mirror 2, the scanning trajectory of the detection light spot can be as shown in scanning trajectory 2 or scanning trajectory 3.

[0157] In the above context, in combination with Figures 5 to 12 the method provided in the embodiments of the present application has been described in detail. Next, in combination with Figure 13 and Figure 14 the device provided in the embodiments of the present application will be described in detail. The description of the device embodiments corresponds to the description of the method embodiments. Therefore, for the content not described in detail, reference may be made to the above method embodiments.

[0158] Exemplarily, Figure 13 a schematic block diagram of a control device (hereinafter referred to as device 1000) provided in the embodiments of the present application is shown. The device may include an acquisition unit 1010 and a processing unit 1020.

[0159] The device 1000 may include units for executing Figures 5 to 12 any of the methods, and each unit in the device 1000 may be used to execute the corresponding processes in any of the above Figures 5 to 12 method embodiments.

[0160] Among them, when the device 1000 is used to execute the method 400 in Figure 6 , the acquisition 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 may be used to: acquire the scanning speed of the first scanning unit 320. The processing unit 1020 may be used to: determine the angular difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit 320. The first steering angle includes the included angle between the first light beam and the first detection light beam at the first time point. The first detection light beam is the light beam emitted from the first light beam through the first optical element 330. The second steering angle includes the included angle between the second light beam and the second detection light beam at the second time point. The second detection light beam is the light beam emitted from the second light beam through the first optical element 330. The first optical element 330 is disposed between the emitting unit 310 and the first scanning unit 320. The first light beam and the second light beam are emitted by the emitting unit 310.

[0162] Exemplarily, the control device may be a lidar, or may be a chip or a processor in the lidar, or may be a terminal (such as a computing platform) in the intelligent driving device for signal processing or control of the lidar, or a chip or a processor in the terminal, or may be a chip or a processor in the control device corresponding to the lidar, etc.

[0163] In some possible implementation manners, 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 processing unit 1020 can be configured to: determine the change in the reflection angle of the first optical element 330 according to the scanning speed of the first scanning unit 320.

[0164] In some possible implementation manners, the first optical element 330 includes a rotatable lens. The first side of the rotatable lens includes a first plane, and the 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 changes linearly at a first position. 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. The processing unit 1020 can be configured to: determine the moving speed of the rotatable lens along the first axis according to the scanning speed of the first scanning unit 320.

[0165] In some possible implementation manners, the first steering angle and the second steering angle are generated by the refraction of the first optical element 330. The processing unit 1020 can be configured to: determine the change speed of the refractive index of the first optical element 330 according to the scanning speed of the first unit.

[0166] In some possible implementation manners, the processing unit 1020 can be configured to: determine the position and / or speed of the target object according to the return light of the detection light beam and the local oscillator light of the light beam emitted by the emitting unit.

[0167] It should be understood that the division of each unit in the above device is only a division of logical functions. In actual implementation, it can be fully or partially integrated into a physical entity, or physically separated. All units of the above device can be implemented entirely in the form of software called by a processor, or entirely in the form of hardware circuits, or partially in the form of software called by a processor, and the remaining part in the form of hardware circuits.

[0168] In the specific implementation process, the above acquisition unit 1010 can be implemented by at least one transceiver or transceiver-related circuit, and the processing unit 1020 can be implemented by at least one processor or processor-related circuit. In one example, one or more processors can determine the change in the refractive index of the first optical element 330 according to the scanning speed of the first scanning unit 320. In one example, one or more processors can determine the change in the attitude of the first optical element 330 according to the scanning speed of the first scanning unit 320. Exemplarily, in the specific implementation process, the device 1000 can be an intelligent driving device provided with a lidar, or a chip or processor disposed in the intelligent driving device.

[0169] Exemplarily, Figure 14It is a schematic block diagram of another control device 2000 (hereinafter referred to as device 2000) provided by an embodiment of the present application. The device 2000 may include: a processor 2010, an interface circuit 2020, and a memory 2030. Among them, the processor 2010, the interface circuit 2020, and the memory 2030 are connected through 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 to receive / send partial parameters through the interface circuit 2020. Optionally, the memory 2030 can be coupled to the processor 2010 through an interface or integrated with the processor 2010.

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

[0171] In the embodiments of the present application, a processor is a circuit with signal processing capabilities. In one implementation, the processor can be a circuit with instruction reading and running capabilities, such as a central processing unit (CPU), a microprocessor, a graphics processing unit (GPU) (which can be understood as a type of microprocessor), or a digital signal processor (DSP), etc.; in another implementation, the processor can implement certain functions through the logical relationship of a hardware circuit, and the logical relationship of this hardware circuit is fixed or can be reconfigured. For example, the processor is a hardware circuit implemented by 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 configuration of the hardware circuit can 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 a type of ASIC, such as a neural network processing unit (NPU), a tensor processing unit (TPU), a deep learning processing unit (DPU), etc.

[0172] The embodiments of the present application also provide a detection system, which includes a transmitting unit, a first optical element, a first scanning unit, and a control platform, and the control platform can include the above-mentioned device 1000 or 2000.

[0173] The embodiments of the present application also provide a computer program product, which includes: computer program code. When the computer program code runs on a computer, it causes the computer to execute any one of the method embodiments described above Figures 5 to 12 and any possible implementation thereof.

[0174] The embodiments of the present application also provide a computer-readable storage medium, which stores program code or instructions. When the computer program code or instructions are executed by the processor of the computer, it causes the processor to implement any one of the method embodiments described above Figures 5 to 12 and any possible implementation thereof.

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

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

[0177] An embodiment of this application also provides an intelligent driving device, which may include any one of the above-mentioned lidar 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 may be a vehicle. The vehicle involved in the embodiments of this application is a vehicle in a broad sense, and may be a means of transportation (such as a commercial vehicle, a passenger vehicle, a motorcycle, a flying vehicle, 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.), an agricultural equipment (such as a lawn mower, a harvester, etc.), a recreational equipment, a toy vehicle, etc. The embodiments of this application do not specifically limit the type of the vehicle. For example, the vehicle in this application may include a pure electric vehicle (pure electric vehicle / battery electric vehicle, pureEV / battery EV), a hybrid electric vehicle (hybrid electric vehicle, HEV), a range-extended electric vehicle (range-extended electric vehicle, REEV), a plug-in hybrid electric vehicle (plug-in hybrid electric vehicle, PHEV) or a new energy vehicle (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 above-described systems, devices and units may refer to the corresponding processes in the foregoing method embodiments, and will not be elaborated herein.

[0180] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or by a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

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

[0182] In several embodiments provided in the present 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 illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For example, 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 displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be in electrical, mechanical, or other forms.

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

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

[0185] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art or a part of this 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 to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application. The foregoing storage medium includes: various media that can store program codes such as USB flash drives, mobile hard disks, read-only memories, random access memories, magnetic disks, or optical discs.

[0186] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, and all should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A lidar system, characterized in that, Comprising: A transmitting unit, a first scanning unit, and a first optical element, wherein the first optical element is disposed between the transmitting unit and the first scanning unit; The transmitting unit is configured to: emit a light beam; The first optical element is configured to: Receive a first light beam at a first time point and emit a first detection light beam, the angle between the first light beam and the first detection light beam being a first turning angle; Receive a second light beam at a second time point and emit a second detection light beam, the angle between the second light beam and the second detection light beam being a second turning angle, and the angular difference between the second turning angle and the first turning angle being determined according to the scanning speed of the first scanning unit; The first scanning unit is configured 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 mirror, 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 turning angle is generated by reflection when the first optical element is at a first reflection angle, the second turning 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.

4. The system according to claim 3, characterized in that, Within a 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 deflection directions of the first optical element and the first scanning unit with respect to the light beam are opposite.

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

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, and the curvature of the first curved surface at a first position changes linearly when the rotatable lens moves along a first axis, the first position including an exit position when the light beam exits through the first curved surface, the first axis being perpendicular to the first plane, and the angular difference between the first turning angle and the second turning angle is generated by the movement of the rotatable lens along the first axis.

7. The system according to claim 6, wherein 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 thermoelectric crystal, or a liquid crystal element, and the change in the refractive index of the first optical element is determined according to the scanning speed of the first scanning unit.

9. The system according to any one of claims 1 to 8, characterized in that, The system further includes a second scanning unit disposed between the first optical element and the first scanning unit, the second scanning unit being configured 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 being 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 transmitting unit is a coherent light beam.

11. A control method, characterized in that, Comprising: Obtain the scanning speed of the first scanning unit; Determine the angular difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit. The first steering angle includes the angle between the first light beam at the first time point and the first detection light beam. The first detection light beam is the light beam emitted from the first light beam through the first optical element. The second steering angle includes the angle between the second light beam at the second time point and the second detection light beam. The second detection light beam is the light beam emitted from the second light beam through the first optical element. The first optical element is disposed between the emitting unit and the first scanning unit. 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 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 according to the scanning speed of the first scanning unit includes: Determine the change in the reflection angle of the first optical element according to the scanning speed of the first scanning unit.

13. The method according to claim 12, wherein The speed of change in the reflection angle of the first optical element includes the rotation speed of the first optical element. 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 deflection directions of the first optical element and the first scanning unit for the light beam are opposite.

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

15. The method according to claim 11, wherein The first optical element includes a rotatable lens. The first side of the rotatable lens includes a first plane, and the second side of the rotatable lens includes a first curved surface. When the rotatable lens moves along the first axis, the curvature of the first curved surface at the first position changes linearly. 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. Determining the angular difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit includes: Determine the moving speed of the rotatable lens along the first axis according to the scanning speed of the first scanning unit.

16. The method according to claim 11, wherein The first steering angle and the second steering angle are generated by the refraction of the first optical element. Determining the angular difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit includes: Determine the change speed of the refractive index of the first optical element according to the 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 disposed between the first optical element and the first scanning unit. The second scanning unit is configured to transmit the detection light beam emitted from 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, Comprising: An acquisition unit configured to acquire the scanning speed of the first scanning unit; A processing unit configured to: determine the angular difference between the first steering angle and the second steering angle according to the scanning speed of the first scanning unit, where the first steering angle includes the angle between the first light beam and the first detection light beam at a first time point, the first detection light beam is the light beam emitted from the first light beam through a first optical element, the second steering angle includes the angle between the second light beam and the second detection light beam at a second time point, the second detection light beam is the light beam emitted from the second light beam through the first optical element, the first optical element is disposed 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.

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. The processing unit is configured to: Determine the change in the reflection angle of the first optical element according to the scanning speed of the first scanning unit.

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

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

23. The control device according to claim 19, wherein The first optical element includes a rotatable lens. The first side of the rotatable lens includes a first plane, and the 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 when the light beam exits through the first curved surface. The first axis is perpendicular to the first plane. The processing unit is configured to: Determine the movement speed of the rotatable lens along the first axis 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 refraction of the first optical element. The processing unit is configured to: Determine the change speed of the refractive index of the first optical element according to the scanning speed of the first unit.

25. The control device according to claim 19, characterized in that, A second scanning unit is disposed between the first optical element and the first scanning unit. The second scanning unit is configured to transmit the detection light beam emitted from 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.

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, Comprising: A memory for storing a computer program; A processor for executing the computer program stored in the memory, so that the device executes the method according to any one of claims 11 to 18.

28. A detection system, characterized in that, Comprising a transmitting unit, a first optical element, a first scanning unit and a control platform, the control platform comprising a control device according to any one of claims 19 to 27.

29. A computer-readable storage medium, characterized in that, On which a computer program is stored, 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 includes computer program code, and when the computer program code runs on a computer, the method according to any one of claims 11 to 18 is executed.

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