LASER RADAR DETECTION METHOD AND LASER RADAR

A detection method of a LiDAR and a LiDAR are provided. The LiDAR includes: a scanner module, the scanner module includes: at least one reflection surface; and the detection method includes: determining multiple corrective detector units based on a pre-stored inclination angle of a surface to be corrected, the surface to be corrected being one of the at least one reflection surface; and performing signal collection by the multiple corrective detector units to determine a point cloud image. Based on the technical solutions of this disclosure, the inclination angle of the surface to be corrected can be compensated to ensure that the determined corrective detector unit corresponds to a fixed field of view direction. Particularly when the scanner module includes multiple reflection surfaces, different corrective detector units are determined based on respective inclination angles of the multiple reflection surfaces, to ensure that each of the reflection surfaces corresponds to a fixed field of view direction based on the determined corrective detector unit, causing inhibition of the occurrence of point cloud jitter among the multiple reflective surfaces.

This application claims priority to Chinese Patent Application No. 202111659798.7 titled “DETECTION METHOD OF LIDAR AND LIDAR” and filed with the China National Intellectual Property Administration on Dec. 30, 2021, the content of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

This disclosure relates to laser detection and, in particular, relates to a detection method of a LiDAR and a LiDAR.

BACKGROUND

LiDAR (light detection and ranging) is a commonly used ranging sensor characterized by long detection range, high resolution, and less environmental interference, and is widely used in fields such as smart robots, unmanned aerial vehicles, and autonomous driving. The LiDAR works by using the time taken by the laser to travel back and forth between the LiDAR and the target, or the frequency shift generated by the frequency modulated continuous light traveling back and forth between the LiDAR and the target, to evaluate information such as the distance or speed of the target.

A LIDAR emits detection light into a three-dimensional space, and the detection light is reflected by the target to be detected, forming an echo signal. The LiDAR receives the echo signal to determine a point cloud image. One type of LiDAR performs detection by reflecting detection light through a reflection surface of a scanner apparatus into a three-dimensional space.

Due to limitations of the manufacturing process, position-orientation control of the reflection surface in the scanner apparatus is challenging and lacks precision, which can easily lead to insufficient light path accuracy and poor stability, manifested as the phenomenon of point cloud jitter.

SUMMARY

Problems to be solved in this disclosure are to provide a detection method of a LiDAR and a LiDAR, to reduce impact of a position and orientation of a reflection surface on a light path, and inhibit occurrence of point cloud jitter.

To solve the problems, this disclosure provides a detection method of a LiDAR. The LiDAR includes a scanner module, the scanner module includes: at least one reflection surface; and the detection method includes: determining multiple corrective detector units based on a pre-stored inclination angle of a surface to be corrected, the surface to be corrected being one of the at least one reflection surface; and performing signal collection by the multiple corrective detector units to determine a point cloud image.

Optionally, the scanner module includes: multiple reflection surfaces; and the detection method further includes: determining the surface to be corrected prior to the determining the multiple corrective detector units, the surface to be corrected being one of the multiple reflection surfaces; and determining the inclination angle of the surface to be corrected based on the determined surface to be corrected. In the step of the determining the multiple corrective detector units, the multiple corrective detector units are determined based on the determined inclination angle of the surface to be corrected, and the multiple corrective detector units correspond to the surface to be corrected.

Optionally, the LiDAR includes a light-emitter module, the light-emitter module includes: multiple light-emitter units, and there is a one-to-one correspondence between the multiple light-emitter units and the multiple corrective detector units; and the step of the performing signal collection by the multiple corrective detector units includes: enabling the light-emitter unit to generate detection light, the detection light forming corresponding echo light after reflected by an object outside the LiDAR; and receiving the echo light by a corresponding corrective detector unit to collect signal.

Optionally, the detection method further includes: determining, after the determining the multiple corrective detector units, multiple corrective light-emitter units based on the inclination angle of the surface to be corrected in combination with the multiple corrective detector units, there being one-to-one correspondence between the multiple corrective light-emitter units and the multiple corrective detector units; and the step of the performing signal collection by the multiple corrective detector units includes: enabling the multiple corrective light-emitter units to generate detection light, the detection light forming corresponding echo light after reflected by an object outside the LiDAR; and receiving the echo light by corresponding corrective detector units to collect signal.

Optionally, each of the corrective light-emitter units includes multiple emitters.

Optionally, the emitter is an independently addressable and independently controlled laser.

Optionally, each of the corrective detector units includes multiple detectors.

Optionally, the detector is an independently addressable and independently controlled detector.

Optionally, the reflection surface rotates around a rotation shaft.

Optionally, the scanner module includes: a rotating mirror, and the reflection surface is a mirror surface of the rotating mirror.

Optionally, the LiDAR includes a light-emitter module to generate detection light; the detection light is emitted after reflected by the surface to be corrected; the emitted detection light forms echo light after reflected by an object outside the LiDAR; and the echo light is reflected by the surface to be corrected to the multiple corrective detector units.

Optionally, the inclination angle of the surface to be corrected includes: a vertical inclination angle and a horizontal inclination angle; and in the step of the determining the multiple corrective detector units, the multiple corrective detector units are determined based on the vertical inclination angle and the horizontal inclination angle.

Accordingly, this disclosure further provides a LiDAR, including: a scanner module, the scanner module includes: at least one reflection surface; and a processor apparatus configured to perform the detection method of this disclosure.

In addition, this disclosure further provides a LiDAR, including: a scanner module, the scanner module including: at least one reflection surface; a corrector module pre-storing an inclination angle of a surface to be corrected and configured to determine multiple corrective detector units based on the inclination angle of the surface to be corrected, the surface to be corrected being one of the at least one reflection surface; and a collector module configured to perform signal collection by the multiple corrective detector units to determine a point cloud image.

Optionally, the scanner module includes: multiple reflection surfaces; the LiDAR further includes: a selector module configured to determine the surface to be corrected, the surface to be corrected being one of the multiple reflection surfaces; and the corrector module determines the inclination angle of the surface to be corrected based on the surface to be corrected determined by the selector module, the corrector module determines the multiple corrective detector units based on the determined inclination angle of the surface to be corrected, and the multiple corrective detector units correspond to the surface to be corrected.

Optionally, the LiDAR includes a light-emitter module, the light-emitter module includes: multiple light-emitter units, and there is a one-to-one correspondence between the multiple light-emitter units and the multiple corrective detector units; and the collector module includes: a detection controller unit configured to control the light-emitter unit to generate detection light, the detection light forming corresponding echo light after reflected by an object outside the LiDAR; and a reception controller unit configured to control a corresponding corrective detector unit to receive the echo light to collect signal.

Optionally, the corrector module is further configured to determine multiple corrective light-emitter units based on the inclination angle of the surface to be corrected in combination with the multiple corrective detector units. There is a one-to-one correspondence between the multiple corrective light-emitter units and the multiple corrective detector units.

The collector module includes: a detection controller unit configured to control the multiple corrective light-emitter units to generate detection light, the detection light forming corresponding echo light after reflected by an object outside the LiDAR; and a reception controller unit configured to control a corresponding corrective detector unit to receive the echo light to collect signal.

Optionally, each of the corrective light-emitter units includes multiple emitters.

Optionally, the emitter is an independently addressable and independently controlled laser.

Optionally, the emitter includes: a vertical cavity surface emitting laser.

Optionally, each of the corrective detector units includes multiple detectors.

Optionally, the detector is an independently addressable and independently controlled detector.

Optionally, the detector includes: a single photon avalanche diode.

Optionally, the reflection surface rotates around a rotation shaft.

Optionally, the scanner module includes: a rotating mirror, and the reflection surface is a mirror surface of the rotating mirror.

Optionally, the LiDAR includes a light-emitter module to generate detection light; the detection light is emitted after reflected by the surface to be corrected; the emitted detection light forms echo light after reflected by an object outside the LiDAR; and the echo light is reflected by the surface to be corrected to the multiple corrective detector units.

Optionally, the inclination angle of the surface to be corrected includes: a vertical inclination angle and a horizontal inclination angle; and the corrector module determines the multiple corrective detector units based on the vertical inclination angle and the horizontal inclination angle.

Compared with the existing technologies, technical solutions of this disclosure have the following advantages:

based on the technical solutions of this disclosure, the multiple corrective detector units are determined based on the pre-stored inclination angle of the surface to be corrected to compensate for the inclination angle of the reflection surface; and signal collection is performed by the multiple corrective detector units to determine a point cloud image. Because he multiple corrective detector units are determined based on the inclination angle of the surface to be corrected, the determination of the corrective detector units can compensate for the inclination angle of the surface to be corrected to ensure that the determined detector unit corresponds to a fixed field of view direction. Particularly when the scanner module includes multiple reflection surfaces, different corrective detector units are determined based on respective inclination angles of the multiple reflection surfaces, to ensure that each of the reflection surfaces corresponds to a fixed field of view direction based on the determined corrective detector unit, causing inhibition of the occurrence of point cloud jitter among the multiple reflective surfaces.

In an optional solution of this disclosure, after the multiple corrective detector units are determined, the multiple corrective light-emitter units are determined based on the inclination angle of the surface to be corrected in combination with the multiple corrective detector units, to perform signal collection by the corrective light-emitter unit and the corrective detector unit. The determination of the multiple corrective light-emitter units can make a receiving field of view of the corrective detector units correspond to a light spot center of the received echo light, to improve the detection efficiency and ensure long ranging distance.

DETAILED DESCRIPTION

As can be known from the BACKGROUND, a LIDAR in the existing technologies has a problem that a reflection surface of a scanner module affects the light path accuracy and stability. Here, the impact of the reflection surface of the scanner module on the light path is analyzed based on a structure of the LiDAR.

With reference toFIG.1, a schematic structural diagram of a LiDAR is shown.

The LiDAR includes: a light-emitter module, a scanner module, and a detector module. The scanner module includes a rotating mirror.

Detection light generated by the light-emitter module11is projected onto a transmission optical module Tx, and the detection light transmitted by the transmission optical module Tx is emitted after reflected by a reflection surface12rin the scanner module12. The emitted detection light forms echo light after reflected by an external target object. The echo light is received and reflected by the reflection surface12rin the scanner module12, projected onto a receiving optical module Rx, transmitted by the receiving optical module Rx, and then projected onto a detector module13.

A distance d between the external target object and the LiDAR is determined based on a time difference Δt between a emission of the detection light by the light-emitter module11and reception of the echo light by the detector module13and based on a ranging principle of time of flight (“TOF”): d=c*Δt/2. c represents the speed of light.

The reflection surface12rin the scanner module12rotates to achieve the detection light scanning. In the LiDAR as shown inFIG.1, the rotating mirror performs 360° scanning to form a scan in a certain field of view of an external space.

A horizontal field of view perpendicular to a rotation shaft is determined by the rotating mirror, and a vertical field of view perpendicular to the horizontal field of view is jointly determined by distribution of a laser/detector in the detector module13of the LiDAR and a position and orientation of the reflection surface12rin the rotating mirror (e.g., a pitch angle of the reflection surface12r).

It can be seen that due to process limitations, the control precision of position and orientation of the reflection surface12ris relatively low. There may be a deviation between an actual position and orientation of the reflection surface12rand an ideal position and orientation of the reflection surface12rduring light path design. There may be an inclination angle, that is, an inclination angle of the reflection surface12r, between the actual position and orientation and the ideal position and orientation of the reflection surface12r. The existence of the inclination angle of the reflection surface12rcan reduce the light path accuracy of the LiDAR, thereby affecting the light path stability.

With reference toFIG.2, a schematic diagram of a scanning field of view after the LiDAR shown inFIG.1is installed on a vehicle is shown.

Particularly, when a scanner apparatus12includes multiple reflection surfaces12r, the control precision of position and orientation of the reflection surfaces12ris relatively low, and it is difficult to maintain position and orientation consistency among the multiple reflection surfaces12r, which can cause inconsistent fields of view corresponding to the multiple reflection surfaces12r, thereby resulting in inconsistent beam angles of the LiDAR among the multiple reflection surfaces12r, and resulting in a problem of point cloud jitter. As shown inFIGS.3and4,FIG.3shows point cloud jitter along a vertical direction caused by a rotating mirror in the LiDAR shown inFIG.1; andFIG.4shows point cloud jitter along a horizontal direction caused by a rotating mirror in the LiDAR shown inFIG.1.

With reference toFIG.5, a principle diagram of a light path for changes of a receiving field of view caused by a rotating mirror in the LiDAR shown inFIG.1is shown.

FIG.5shows a schematic diagram of a light path in a vertical field of view. The ideal position and orientation12idof the reflection surface12ris parallel to the rotation shaft (i.e., without an inclination angle or with an inclination angle of) 0°, while there is 0° (i.e., an inclination angle of) 0° between the actual position and orientation12reof the reflection surface12rand the rotation shaft.

It should be noted that, as shown inFIG.6, the detector module13of the LiDAR includes multiple detector units13a, and the detector units13ainclude multiple detectors13b. The detector13bcan be a single photon avalanche diode (“SPAD”).

As shown inFIG.5, when the reflection surface12ris in the ideal position and orientation12id, echo light received by an i-th detector unit13iis echo light51idin a field of view direction of the i-th channel (e.g., a light path as shown by the dotted line51idinFIG.5); however, when the reflection surface12ris in the actual position and orientation12re, echo light received by the i-th detector unit is echo light51re(as shown by the solid line51reinFIG.5) from a different field of view direction than originally intended (i.e., when12ris in the ideal position and orientation12id), and in such a case, a same detector unit corresponds to different fields of view when the reflection surface12ris in different position and orientations, there is detection angle jitter among different position and orientations of the reflection surface.

Moreover, there is the angle θ° between the actual position and orientation12reand the ideal position and orientation12idof the reflection surface12r, that is, when the inclination angle is 0°, in the vertical field of view, a deflection angle of the echo light is 2*θ°. For example, when there is an angle of 0.1° between the actual position and orientation12reand the ideal position and orientation12idof a reflecting mirror, a vertical field of view angle of the echo light received by the same detector unit shifts by 0.2°, meaning the field of view direction changes by 2*θ°, that is, there is an angle of 2*θ° between the echo light51idand the echo light51re.

It can be seen that when position and orientations of the multiple reflection surfaces12rin the scanner apparatus12are inconsistent, and the inclination angles between the actual position and orientations12reand the ideal position and orientations12idof different reflection surfaces12rare different, the field of view direction of the echo light received by the same detector unit13a(as shown inFIG.6) changes with the scanning process and variation of the reflection surface12r. Each of the reflection surfaces corresponds to a complete traversal of the field of view, so that point cloud jitter occurs between different reflection surfaces.

Typically, during the integration and assembly of the LiDAR, the inclination angle of the reflection surface12rin the scanner apparatus is actively adjusted to achieve the highest consistency among the inclination angles of the multiple reflection surfaces12r. As shown inFIG.1, for a LiDAR with a double-sided rotating mirror, a rotation shaft direction of the double-sided rotating mirror is changed to cause inclination angles of two reflection surfaces12rof the double-sided rotating mirror to be the same. After the assembly of the LiDAR is completed, inclination angles of multiple rotating mirrors are measured by measurement and calibration. The inclination angles of multiple rotating mirrors are used as calibrated compensation values to compensate for angle information of the received echo light, thereby determining a correct point cloud image. In this case, point clouds outputted in the presence of the inclination angles are as shown inFIGS.3and4.

To solve the technical problems, this disclosure provides a detection method of a LiDAR. The LiDAR includes a scanner module, the scanner module includes: at least one reflection surface; and the detection method includes: determining multiple corrective detector units based on a pre-stored inclination angle of a surface to be corrected, the surface to be corrected being one of the at least one reflection surface; and performing signal collection by the multiple corrective detector units to determine a point cloud image.

In the technical solutions of this disclosure, the multiple corrective detector units are determined based on the inclination angle of the surface to be corrected. The determination of the corrective detector units can compensate for the inclination angle of the surface to be corrected to ensure that the determined corrective detector unit corresponds to a fixed field of view direction. Particularly when the scanner module includes multiple reflection surfaces, different corrective detector units are determined based on respective inclination angles of the multiple reflection surfaces, to ensure that each of the reflection surfaces corresponds to a fixed field of view direction based on the determined corrective detector unit, causing inhibition of the occurrence of point cloud jitter among the multiple reflective surfaces.

To make the objects, features, and advantages of this disclosure more obvious and understandable, some embodiments of this disclosure are described in detail below with reference to the drawings.

With reference toFIG.7, a schematic structural diagram of an embodiment of a LiDAR of this disclosure is shown.

The LiDAR includes: a light-emitter module110, a scanner module120, and a detector module130.

The light-emitter module110is configured to generate detection light111e. The detection light111egenerated by the light-emitter module110is projected onto a transmission optical module Tx, and the detection light transmitted by the transmission optical module Tx is projected onto the scanner module120.

As shown inFIG.8, in some embodiments of this disclosure, the light-emitter module110of the LiDAR includes: multiple emitters111i. Specifically, the emitter111iis an independently addressable and independently controlled laser (as shown by circle101inFIG.9).

Specifically, as shown inFIGS.8and9, the multiple emitters111iare arranged in an array to form an emission array. By applying different voltages to connection wires of A1to A3and P1to P6, different emitters111can be selected, achieving independent addressing and independent control of the emitters111i. Specifically, in some embodiments of this disclosure, the emitters111iinclude: a vertical cavity surface emitting laser (“VCSEL”).

The scanner module120is configured to change an emission angle of the detection light111e. The scanner module120includes at least one reflection surface120r. The reflection surface120rreflects the detection light111e, causing the detection light111eto be emitted into an external space of the LiDAR.

In some embodiments of this disclosure, the scanner module120includes a rotation shaft120i; and the reflection surface120rrotates around the rotation shaft120i, that is, the at least one reflection surface120rrotates around the rotation shaft120i. Specifically, in the embodiment as shown inFIG.7, the scanner module120includes: a rotating mirror, the reflection surface120ris a mirror surface of the rotating mirror; and a rotation shaft of the rotating mirror is the rotation shaft120i.

As shown inFIG.7, the rotating mirror is a double-sided rotating mirror, that is, the scanner module120includes 2 reflection surfaces120r, and the 2 reflection surfaces120rrotate around the rotation shaft120i.

After emitted into the external space of the LiDAR, the emitted detection light112forms echo light131after reflected by a target to be measured. The echo light131is received and reflected by a same reflection surface120rin the scanner module120, then projected onto the receiving optical module Rx, transmitted by the receiving optical module Rx, and then projected onto the detector module130.

The detector module130of the LiDAR is configured to receive echo light122transmitted by the receiving optical module Rx to achieve detection.

As shown inFIGS.8and10, the detector module130includes multiple detectors131i. Specifically, the detector131iis an independently addressable and independently controlled detector (as shown by circle101inFIG.10).

Specifically, the multiple detectors131iare arranged in an array to form a receiving array. Each of the detectors131ican be independently powered on and independently read out. By powering on or reading only a detector on a specific address wire, a signal of the single detector can be read. Specifically, in some embodiments of this disclosure, the detector131iincludes a single photon avalanche diode. The circle101inFIG.11is a unit of the detector131i, including a single photon avalanche diode101aand a quenching resistor101b.

It should be noted that, as shown inFIG.8, the light-emitter module110includes multiple light-emitter units111, each of the light-emitter units111includes two or more of the emitters111i; the detector module130includes multiple detector units131, and each of the detector units131includes two or more of the detectors131i. After the LiDAR is calibrated, there is a one-to-one correspondence between the multiple light-emitter units111and the multiple detector units131, that is, an emission field of view of the light-emitter unit111in a far field is the same as a receiving field of view of a corresponding detector unit131in the far field, to form a physical channel. That is to say, in the far field, the field of view of the light-emitter unit111is the same as the field of view of the corresponding detector unit131. In such a case, echo light formed by reflection of the detection light emitted from the light-emitter unit111is received by the corresponding detector unit131, that is, each physical channel has a fixed field of view direction of the channel, for example, 40° from a vertical field of view direction.

It should be further noted that the implementation of the light-emitter unit111including multiple emitters is only an example. In other embodiments of this disclosure, the light-emitter unit111can further be an independent laser, such as an edge-emitting laser (“EEL”).

Further with reference toFIG.8, the LiDAR further includes: a processor apparatus140. The processor apparatus can implement the detection method of this disclosure to compensate for the inclination angle of the reflection surface in the scanner module.

With reference toFIG.11, a schematic flow chart of a detection method implemented by the processor apparatus in the LiDAR embodiment shown inFIG.8.

The detection method includes: performing step S110: determining multiple corrective detector units based on a pre-stored inclination angle of a surface to be corrected, the surface to be corrected being one of the at least one reflection surface; and performing step S120: performing signal collection by the multiple corrective detector units to determine a point cloud image.

Because the multiple corrective detector units are determined based on the inclination angle of the surface to be corrected, the determination of the corrective detector units can compensate for the inclination angle of the surface to be corrected to ensure that the determined corrective detector unit corresponds to a fixed field of view direction. Particularly when the scanner module includes multiple reflection surfaces, different corrective detector units are determined based on respective inclination angles of the multiple reflection surfaces, to ensure that each of the reflection surfaces corresponds to a fixed field of view direction based on the determined corrective detector unit, causing inhibition of the occurrence of point cloud jitter among the multiple reflective surfaces.

As shown inFIGS.7and11, step S110is first performed: determining multiple corrective detector units based on a pre-stored inclination angle of a surface to be corrected. The surface to be corrected is one of the at least one reflection surface120r(as shown inFIG.8).

The step of determining the corrective detector units is configured to compensate for the inclination angle of the surface to be corrected using positions of the corrective detector units.

As shown inFIG.7, in some embodiments of this disclosure, the scanner module120includes multiple reflection surfaces120r. In such a case, as shown inFIG.11, the detection method further includes: performing step S131: determining the surface to be corrected, the surface to be corrected being one of the multiple reflection surfaces, before performing step S110: determining the multiple corrective detector units.

Specifically, the scanner apparatus120includes a rotating mirror, the rotating mirror is an n-sided rotating mirror, and the reflection surface is a mirror surface of the rotating mirror, that is, the scanner apparatus120includes n reflection surfaces. In such a case, the step S131of determining the surface to be corrected is performed, in which the surface to be corrected is one of n mirror surfaces of the n-sided rotating mirror. In the embodiment as shown inFIG.7, the scanner module120includes 2 reflection surfaces120r, and the surface to be corrected is one of 2 mirror surfaces of the double-sided rotating mirror.

After the surface to be corrected is determined, the step S132is performed: determining the inclination angle of the surface to be corrected based on the determined surface to be corrected.

The LiDAR pre-stores the inclination angle of the at least one reflection surface. When there are multiple reflection surfaces, the LiDAR pre-stores inclination angles of the multiple reflection surfaces, and there is a one-to-one correspondence between the inclination angles of the multiple reflection surfaces and the multiple reflection surfaces.

It should be noted that the inclination angle of the surface to be corrected represents an angle between an actual position and orientation and an ideal position and orientation of the surface to be corrected. The ideal position and orientation of the surface to be corrected is a position and orientation of the reflection surface in design requirements of the scanner module120; and the actual position and orientation of the surface to be corrected is a position and orientation of the reflection surface after the scanner module120has been manufactured and assembled.

Specifically, as shown inFIG.12, the scanner module120includes 2 reflection surfaces. In the design requirements, ideal position and orientations121of the 2 reflection surfaces of the scanner module120are parallel to each other, and are parallel to the rotation shaft120i(as shown by the dotted line inFIG.12); and after actual manufacture and assembly are completed, an actual position and orientation122of one of the reflection surfaces deviates from the ideal position and orientation121(as shown by the solid line inFIG.12).

As shown inFIG.13, in some other embodiments of this disclosure, the scanner apparatus230includes 3 reflection surfaces. In the design requirements, ideal position and orientations231of the 3 reflection surfaces of the scanner module230form a triangular prism with a cross section being an equilateral triangle, the rotation shaft220iis located at a position of a connection line of a bottom center of the triangular prism; and after the actual manufacture and assembly are completed, an actual position232of1of the reflection surfaces deviates from the ideal position and orientation121(as shown by the solid line inFIG.13).

It should be noted thatFIGS.12and13only illustrate the deviation of one reflection surface among the multiple reflection surfaces of the scanner apparatus from its ideal position. However, the number of reflection surfaces deviating from the ideal position is not limited in this disclosure. In some other embodiments of this disclosure, among the multiple reflection surfaces of the scanner apparatus, more reflection surfaces may deviate from ideal positions thereof.

In addition, in some embodiments of this disclosure, the inclination angle of the surface to be corrected includes: a vertical inclination angle θ and a horizontal inclination angle ϕ. The vertical inclination angle θ, that is, a pitch angle, of the surface to be corrected represents an angle of projection of an angle between an actual position and orientation and an ideal position and orientation of the reflection surface in a plane of the rotation shaft; and the horizontal inclination angle, that is, a horizontal offset angle, of the surface to be corrected represents an angle of projection of an angle between an actual position and orientation and an ideal position and orientation of the reflection surface in a plane perpendicular to the rotation shaft.

The LiDAR pre-stores at least one group of inclination angles, each group of inclination angles includes a vertical inclination angle θ and a horizontal inclination angle q corresponding to a same reflection surface in the scanner module120. That is to say, the LiDAR pre-stores n groups of inclination angles: (θ1, ϕ1), (θ2, ϕ2), . . . , (θn, ϕn). There is a one-to-one correspondence between the n groups of inclination angles and the n mirror surfaces of the scanner module120.

It should be noted that the at least one group of inclination angles pre-stored in the LiDAR can be determined in a calibration process of the LiDAR. That is to say, in some embodiments of this disclosure, the calibration process of the LiDAR includes: measuring an inclination angle of at least one reflection surface in the scanner module120.

In such a case, the step S132of determining the inclination angle of the surface to be corrected based on the determined surface to be corrected is performed, in which the inclination angle of the surface to be corrected is determined based on a reflection surface as the surface to be corrected. Specifically, the surface to be corrected is an i-th reflection surface of the scanner module120, that is, an i-th mirror surface of the n-sided rotating mirror (i is an integer greater than or equal to 1 and less than or equal to n), and the inclination angle is an i-th group of inclination angles, (θi, ϕi).

Further with reference toFIG.11, after the inclination angle of the surface to be corrected is determined, the step S110is performed: determining multiple corrective detector units131.

In some embodiments of this disclosure, the scanner module includes multiple reflection surfaces, and the surface to be corrected is one of the multiple reflection surfaces. In such a case, the step S110of determining the multiple corrective detector units is performed, in which the multiple corrective detector units are determined based on the determined inclination angle of the surface to be corrected, and the multiple corrective detector units correspond to the determined surface to be corrected.

In addition, as shown inFIGS.8and10, the detector module130of the LiDAR includes multiple detectors131i. In such a case, each of the corrective detector units includes two or more of the detectors131i.

Using the electronic aperture function of the detector array formed by multiple detectors131i, wherein the detectors131iare independently addressable and independently controllable for readout, the photosensitive region corresponding to a channel can be changed through electrical control. Before each reception of the echo light, the photosensitive region (region of interest, “ROI”) is changed to shift, to compensate for the inclination angle of the corresponding surface to be corrected. This ensures that each corresponding corrective detector unit receives echo light in a fixed channel field of view direction. For example, a field of view direction of an i-th channel corresponds to a vertical field of view direction of 40°, when a surface to be corrected 1 is at a first inclination angle, a readout data of a first corrective detector unit is used, and when a surface to be corrected 2 in a second inclination angle, a readout data of a second corrective detector unit is used, to ensure that both of the 2 corrective detector units corresponds to a vertical field of view direction of 40°, causing a receiving field of view of the LiDAR to remain stable at a fixed angle, and avoiding or decreasing detection angle fluctuation among the multiple reflection surfaces.

Specifically, as mentioned, the inclination angle of the surface to be corrected includes: the vertical inclination angle θ and the horizontal inclination angle ϕ. The step S110of determining the multiple corrective detector units is performed, in which the multiple corrective detector units are determined based on the vertical inclination angle θ and the horizontal inclination angle ϕ.

With reference toFIG.14, a schematic diagram of a light path in a vertical field of view of a detection method implemented by the processor apparatus in the embodiment of the LiDAR shown inFIG.8is shown.

Both emitted detection light and received echo light are reflected by the surface to be corrected120ri, and the surface to be corrected120ri; has an inclination angle, that is, there is an angle θ; between an ideal position and orientation120idiand an actual position and orientation120reiof the surface to be corrected120ri. A position of a reflection point of echo light in a field of view direction of a b-th channel (as shown by solid arrow Rband dotted arrow Rb′ in the figure, where the solid arrow Rband the dotted arrow Rb′ are parallel to each other, Rbshows echo light projected at the actual position and orientation120rei, and Rb′ shows echo light projected at the ideal position and orientation120idi) offsets on the surface to be corrected120ri(offset from point O′ at the ideal position and orientation120idito point O at the actual position and orientation120rei). In this case, an ideal detector unit131idbcannot receive the echo light in the field of view direction of the b-th channel. In this case, the ideal detector unit13lid, actually receives echo light in a field of view direction Rk′, there is an angle Δθ=2*θi; between the Rk′ and Rb′. The echo light in the field of view direction of the b-th channel is received by a corrective detector unit130chb.

Specifically,FIG.14shows a schematic light path in a vertical field of view.

The detector module130is located at a focal plane position of the optical receiving assembly Rx. In such a case, prior to compensation, an ordinate of a center position of a b-th ideal detector unit131idbis yb, b is the channel number, and a vertical field angle of a field of view of the b-th channel corresponding to the b-th ideal detector unit131idbis θb, that is, a vertical field angle of detection light emission corresponding to the echo light received by a b-th detector unit is:

f is the focal length of the optical receiving assembly Rx.

The LiDAR pre-stores n groups of inclination angles with one-to-one correspondence between the n reflection surfaces in the scanner module120and the n groups of inclination angles, and vertical inclination angles of the n reflection surfaces are θ1, θ2, . . . , θn, respectively. The vertical inclination angle corresponding to the surface to be corrected120riis θi. Both the emitted detection light and the received echo light are reflected by the surface to be corrected120ri. In such a case, an offset angle in a vertical direction of reflected light formed by reflection of echo light Rbin the field of view direction of the b-th channel from the surface to be corrected120riis Δθ=2*θi, that is, a position of a light spot formed by the reflected light on the detector module130is translated by Δy=Δθ*f along a corresponding direction. In such a case, the step S110of determining the multiple corrective detector units based on the determined inclination angle of the surface to be corrected is performed, in which the difference Δy between an ordinate of a center position of the determined b-th corrective detector unit130chband an ordinate of a center position of the b-th detector unit is determined. Moreover, a direction in which the center position of the b-th corrective detector unit points to the center position of the b-th detector unit is opposite to an offset direction of a reflection point position of the surface to be corrected120ri.

It can be seen that, the step S110of determining the multiple corrective detector units is performed, in which based on the inclination angle of the surface to be corrected, the determined corrective detector units reversely translate the photosensitive region in the detector module130by Δy. In such a case, for the b-th corrective detector unit131chb, a vertical field angle of detection light corresponding to the received echo light is

that is, equal to a corresponding field angle when the surface to be corrected120ridoes not have an inclination angle (vertical inclination angle θi=0).

With reference toFIG.15, a schematic diagram of a light path in a horizontal field of view of a detection method implemented by the processor apparatus in the embodiment of the LiDAR shown inFIG.8is shown.

The compensation principle in the horizontal field of view is similar to the compensation principle in the vertical field of view.

Specifically,FIG.15shows a schematic light path in the horizontal field of view.

Prior to compensation, an abscissa of a center position of the b-th ideal detector unit131idbis xb, b is the channel number, A horizontal field angle of a field of view of the b-th channel corresponding to the b-th ideal detector unit131idbis ϕb, that is, a horizontal field angle of detection light emission corresponding to the echo light received by the b-th detector unit is:

f is the focal length of the optical receiving assembly Rx.

The LiDAR pre-stores n groups of inclination angles with one-to-one correspondence between the n reflection surfaces in the scanner module120and the n groups of inclination angles, and horizontal inclination angles of the n reflection surfaces are ϕ1, ϕ2, . . . , ϕn, respectively. The horizontal inclination angle corresponding to the surface to be corrected120riis ϕi. Both the emitted detection light and the received echo light are reflected by the surface to be corrected120ri. In such a case, an offset angle in a horizontal direction of reflected light formed by reflection of the echo light Rbin the field of view direction of the b-th channel from the surface to be corrected120riis Δϕ=2*ϕi, that is, a position of the light spot formed by the reflected light on the detector module130is translated by Δx=Δϕ*f along a corresponding direction. In such a case, the step S110of determining the multiple corrective detector units based on the determined inclination angle of the surface to be corrected is performed, in which a difference Δx between an abscissa of the center position of the b-th corrective detector unit130chband an abscissa of the center position of the b-th detector unit is determined. Moreover, a direction in which the center position of the b-th corrective detector unit points to the center position of the b-th detector unit is opposite to an offset direction of a reflection point position of the surface to be corrected120ri.

It can be seen that, the step S110of determining the multiple corrective detector units is performed, in which based on the inclination angle of the surface to be corrected, the determined corrective detector unit reversely translate the region of interest in the detector module130by Δx. In such a case, for the b-th corrective detector unit131chb, a horizontal field angle of detection light emission corresponding to the received echo light is

that is, equal to a corresponding field angle when the surface to be corrected120ridoes not have an inclination angle (horizontal inclination angle ϕi=0).

In such a case, the determination of the corrective detector unit can compensate for the inclination angle of the surface to be corrected, to ensure that the determined corrective detector unit corresponds to a fixed field of view direction. Particularly when the scanner module includes multiple reflection surfaces, different corrective detector units are determined based on respective inclination angles of the multiple reflection surfaces, to ensure that each of the reflection surfaces corresponds to a fixed field of view direction based on the determined corrective detector unit, causing inhibition of the occurrence of point cloud jitter among the multiple reflective surfaces.

It should be noted that the ideal detector unit, such as the b-th ideal detector unit13lid, inFIGS.14and15, is a detector unit prior to compensation, that is, the detector unit131determined by calibration of the LiDAR inFIG.8. The ideal detector unit includes two or more of the detectors, and the two or more detectors in the ideal detector unit are at least partially different from multiple detectors in the corrective detector unit.

It should be further noted that, as mentioned, in some embodiments of this disclosure, the detector module130includes multiple detectors131ithat are independently powered on and independently read out. In such a case, a receiving region of a receiving array can be changed by powering only a detector on a specific address wire or reading only a signal of a detector on a specific address wire, to achieve the purpose of maintaining a stable field of view.

Further with reference toFIGS.8and11, in some embodiments of this disclosure, the light-emitter module110of the LiDAR includes multiple independently addressable and independently controlled lasers. In such a case, the detection method further includes: after performing the step S110: determining the multiple corrective detector units, performing S140: determining multiple corrective light-emitter units based on the inclination angle of the surface to be corrected in combination with the multiple corrective detector units, there being one-to-one correspondence between the multiple corrective light-emitter units and the multiple corrective detector units.

The one-to-one correspondence between the multiple corrective light-emitter units and the multiple corrective detector units means that a corrective light-emitter unit and a corresponding corrective detector unit have a same field of view angle in a far field, that is, in the far field, an emission field of view angle of the corrective light-emitter unit is the same as a receiving field of view angle of the corresponding corrective detector unit. Specifically, different voltages are applied to connection wires of the emission array, to select different emitters to emit light.

It should be noted that a light emitter module110of the LiDAR includes multiple emitters. In such a case, each of the corrective light-emitter units includes two or more of the emitters. Based on the determination of the corrective light-emitter unit, the receiving field of view angle of the corrective detector unit is the same as the emission field of view angle of the corrective light-emitter unit, to ensure the ranging capacity and the detection efficiency of the LiDAR.

Further with reference toFIG.11, after the corrective detector unit and the corrective light-emitter unit are determined, the detection method further includes: performing the step S120: performing signal collection by the multiple corrective detector units to determine the point cloud image.

With reference toFIGS.7and16, the step S120of performing signal collection by the multiple corrective detector units131to determine the point cloud image is performed, including: first enabling the multiple corrective light-emitter units111′ to generate detection light, the detection light forming corresponding echo light after reflected by an object outside the LiDAR; and receiving the echo light by a corresponding corrective detector unit131to collect signal.

Specifically, the detection light is emitted after reflected by the surface to be corrected; the emitted detection light forms echo light after reflected by an object outside the LiDAR; and the echo light is reflected by the surface to be corrected to the multiple corrective detector units. The surface to be corrected is one of the multiple reflection surfaces of the Because the corrective detector unit131is determined prior to signal collection, and the corrective detector unit131is determined based on the inclination angle of the surface to be corrected, that is, positions of the corrective detector unit131has been changed to compensate for the deflection caused by the inclination angle of the surface to be corrected, thereby achieving the effects of maintaining a stable field of view.

In addition, with reference toFIG.16, a schematic diagram of implementing signal collection by the corrective light-emitter units111′ and the corrective detector unit131in the embodiment of the LiDAR shown inFIG.8is shown.

The corrective light-emitter unit111′ is determined based on the inclination angle of the surface to be corrected and the corrective detector unit131. In such a case, when a signal is emitted or received, the light spot on the receiving array is still located at a center position of the corrective detector unit131, that is, the corrective detector unit can receive all energy of an echo light spot in a field of view direction of a corresponding channel (the circle in the figure represents the light spot), to improve the detection efficiency and the ranging capacity.

It should be noted that, in other embodiments of this disclosure, as shown inFIG.17, the LiDAR includes a light-emitter module, the light-emitter module210includes: multiple light-emitter units211, and there is a one-to-one correspondence between the multiple light-emitter units211and the multiple corrective detector units231; the step S120of performing signal collection by the multiple corrective detector units231is performed, including: enabling the multiple light-emitter units211to generate detection light, the detection light forming corresponding echo light after reflected by an object outside the LiDAR; and receiving the echo light by a corresponding corrective detector unit231to collect signal.

Accordingly, this disclosure further provides a LiDAR.

With reference toFIG.7, a schematic structural diagram of an embodiment of a LiDAR of this disclosure is shown.

The LiDAR includes: a light-emitter module110and a detector module130.

The light-emitter module110is configured to generate detection light111e. The detection light111egenerated by the light-emitter module110is projected onto a transmission optical module Tx, and the detection light transmitted by the transmission optical module Tx is projected onto the scanner module120.

As shown inFIG.8, in some embodiments of this disclosure, the light-emitter module110of the LiDAR includes: multiple emitters111i. Specifically, the emitter111iis an independently addressable and independently controlled laser (as shown by circle101inFIG.9).

Specifically, as shown inFIGS.8and9, the multiple emitters111are arranged in an array to form an emission array. By applying different voltages to connection wires of A1to A3and P1to P6, different emitters111are selected, achieving independent addressing and independent control of the emitters111i. Specifically, in some embodiments of this disclosure, the emitters111iinclude: a vertical cavity surface emitting laser (“VCSEL”).

The detector module130is configured to receive echo light122transmitted by the receiving optical module Rx to achieve detection.

As shown inFIGS.8and10, the detector module130includes multiple detectors131i. Specifically, the detector131iis an independently addressable and independently controlled detector (as shown by circle101inFIG.10).

Specifically, the multiple detectors131iare arranged in an array to form a receiving array. Each of the detectors131ican be independently powered on and independently read out. By powering on or reading only a detector on a specific address wire, a signal of the single detector can be read. Specifically, in some embodiments of this disclosure, the detector131iincludes a single photon avalanche diode. The circle101inFIG.11is a unit of the detector131i, including a single photon avalanche diode101aand a quenching resistor101b.

It should be noted that the light-emitter module110includes multiple light emitter units, each of the light-emitter units includes two or more of the emitters111i; the detector module130includes multiple detector units, and each of the detector units includes two or more of the detectors131i. After the LiDAR is calibrated, there is a one-to-one correspondence between the multiple light-emitter units and the multiple light-emitter units, that is, an emission field of view of the light-emitter unit in a far field is the same as a receiving field of view of a corresponding detector unit in a far field to form a physical channel. That is to say, at a far-field position, the field of view of the light-emitter unit is the same as the field of view of the corresponding detector unit. In such a case, echo light formed by reflection of the detection light emitted from the light-emitter unit is received by a corresponding receiving unit, that is, each physical channel has a fixed field of view direction of the channel.

It should be further noted that the implementation of the light-emitter unit including multiple emitters is only an example. In other embodiments of this disclosure, the light-emitter unit can further be an independent laser, such as an edge-emitting laser (“EEL”).

Further with reference toFIG.7, the LiDAR further includes: a scanner module120.

The scanner module120is configured to change an emission angle of the detection light111e. The scanner module120includes at least one reflection surface120r. The reflection surface120rreflects the detection light111e, causing the detection light111eto be emitted into an external space of the LiDAR.

In some embodiments of this disclosure, the scanner module120includes a rotation shaft120i; and the reflection surface120rrotates around the rotation shaft120i, that is, the at least one reflection surface120rrotates around the rotation shaft120i. Specifically, in the embodiment as shown inFIG.7, the scanner module120includes: a rotating mirror, the reflection surface120ris a mirror surface of the rotating mirror; and a rotation shaft of the rotating mirror is the rotation shaft120i.

As shown inFIG.7, the rotating mirror is a double-sided rotating mirror, that is, the scanner module120includes 2 reflection surfaces120r, and the 2 reflection surfaces120rrotate around the rotation shaft120i.

After emitted into the external space of the LiDAR, the emitted detection light112forms echo light131after reflected by a target to be measured. The echo light131is received and reflected by a same reflection surface120rin the scanner module120, then projected onto the receiving optical module Rx, transmitted by the receiving optical module Rx, and then projected onto the detector module130.

Further with reference toFIG.8, the LiDAR further includes: a processor apparatus140, the processor apparatus140is connected to both the light-emitter module110and the detector module130, and the processor apparatus140is configured to control the light-emitter module110and the detector module130to perform signal collection, to determine the point cloud image.

With reference toFIG.18, a functional block diagram of the processor apparatus in the embodiment of the LiDAR shown inFIG.8is shown.

The processor apparatus140includes: a corrector module141, the corrector module141pre-storing an inclination angle of a surface to be corrected, the corrector module141is configured to determine multiple corrective detector units based on the inclination angle of the surface to be corrected, the surface to be corrected being one of the at least one reflection surface; and a collector module142, the collector module142is configured to perform signal collection by the multiple corrective detector units to determine a point cloud image.

The corrector module141is configured to compensate for the inclination angle of the surface to be corrected using a position of the corrective detector unit.

As shown inFIG.7, in some embodiments of this disclosure, the scanner module120includes multiple reflection surfaces120r. In such a case, as shown inFIG.18, the processor apparatus140further includes: a selector module143. The selector module143is configured to determine the surface to be corrected. The surface to be corrected is one of the multiple reflection surfaces.

Specifically, the scanner apparatus120includes a rotating mirror, the rotating mirror is an n-sided rotating mirror, and the reflection surface is a mirror surface of the rotating mirror, that is, the scanner apparatus120includes n reflection surfaces.

In such a case, the selector module143selects one mirror surface from n mirror surfaces of the n-sided rotating mirror as the surface to be corrected, that is, the surface to be corrected is one of the n mirror surfaces of the n-sided rotating mirror. In the embodiment as shown inFIG.7, the scanner module120includes 2 reflection surfaces120r, and the selector module143selects one mirror surface from 2 mirror surfaces of the double-sided rotating mirror as the surface to be corrected, that is, the surface to be corrected is one of the 2 mirror surfaces of the double-sided rotating mirror.

The corrector module141determines the inclination angle of the surface to be corrected based on the surface to be corrected determined by the selector module143.

The corrector module141pre-stores the inclination angle of the at least one reflection surface in the scanner module120. When there are multiple reflection surfaces, the LiDAR pre-stores inclination angles of the multiple reflection surfaces, and there is a one-to-one correspondence between the inclination angles of the multiple reflection surfaces and the multiple reflection surfaces.

It should be noted that the inclination angle of the surface to be corrected represents an angle between an actual position and orientation and an ideal position and orientation of the surface to be corrected. The ideal position and orientation of the surface to be corrected is a position and orientation of one of the reflection surfaces in design requirements of the scanner module120; and the actual position and orientation of the surface to be corrected is a position and orientation of the reflection surface after the manufacture and assembly of the scanner module120are completed.

Specifically, as shown inFIG.12, the scanner module120includes 2 reflection surfaces. In the design requirements, ideal position and orientations121of the 2 reflection surfaces of the scanner module120are parallel to each other, and are parallel to the rotation shaft120i(as shown by the dotted line inFIG.12); and after actual manufacture and assembly are completed, an actual position and orientation122of one of the reflection surfaces deviates from the ideal position and orientation121(as shown by the solid line inFIG.12).

As shown inFIG.13, in some other embodiments of this disclosure, the scanner apparatus230includes 3 reflection surfaces. In the design requirements, ideal position and orientations231of the 3 reflection surfaces of the scanner module230form a triangular prism with a cross section being an equilateral triangle, the rotation shaft220iis located at a position of a connection line of a bottom center of the triangular prism; and after the actual manufacture and assembly are completed, an actual position232of1of the reflection surfaces deviates from the ideal position and orientation121(as shown by the solid line inFIG.13).

It should be noted thatFIGS.12and13only illustrate the deviation of one reflection surface among the multiple reflection surfaces of the scanner apparatus from its ideal position. However, the number of reflection surfaces deviating from the ideal position is not limited in this disclosure. In some other embodiments of this disclosure, among the multiple reflection surfaces of the scanner apparatus, more reflection surfaces may deviate from ideal positions thereof.

In addition, in some embodiments of this disclosure, the inclination angle of the surface to be corrected includes: a vertical inclination angle θ and a horizontal inclination angle ϕ. The vertical inclination angle θ, that is, a pitch angle, of the surface to be corrected represents an angle of projection of an angle between an actual position and orientation and an ideal position and orientation of one of the reflection surfaces in a plane of the rotation shaft; and the horizontal inclination angle ϕ, that is, a horizontal offset angle, of the surface to be corrected represents an angle of projection of an angle between an actual position and orientation and an ideal position and orientation of one of the reflection surfaces in a plane perpendicular to the rotation shaft.

The corrector module141pre-stores at least one group of inclination angles, each group of inclination angles includes a vertical inclination angle θ and a horizontal inclination angle φ corresponding to a same reflection surface in the scanner module120. That is to say, the LiDAR pre-stores n groups of inclination angles: (θ1, ϕ1), (θ2, ϕ2), . . . , (θn, ϕn). There is a one-to-one correspondence between the n groups of inclination angles and the n mirror surfaces of the scanner module120.

It should be noted that the at least one group of inclination angles pre-stored in the corrector module141can be determined in a calibration process of the LiDAR. That is to say, in some embodiments of this disclosure, the at least one group of inclination angles pre-stored in the corrector module141is measured in the calibration process of the LiDAR.

In such a case, the corrector module141reads the at least one group of pre-stored inclination angles, and determines the inclination angle of the surface to be corrected based on the surface to be corrected determined by the selector module143. Specifically, the surface to be corrected is an i-th reflection surface of the scanner module120, that is, an i-th mirror surface of the n-sided rotating mirror (i is an integer greater than or equal to 1 and less than or equal to n), and the inclination angle is an i-th group of inclination angles, (Oi, di).

After determining the inclination angle of the surface to be corrected, the corrector module141determines the multiple corrective detector units131.

In some embodiments of this disclosure, the scanner module120includes multiple reflection surfaces, and the surface to be corrected is one of the multiple reflection surfaces. The corrector module141determines the multiple corrective detector units based on the determined inclination angle of the surface to be corrected, and the multiple corrective detector units correspond to the determined surface to be corrected.

In addition, as shown inFIGS.8and10, the detector module130of the LiDAR includes multiple detectors131i. In such a case, each of the corrective detector units includes two or more of the detectors131i.

Using the electronic aperture function of the detector array formed by multiple detectors131i, wherein the detectors131iare independently addressable and independently controllable for readout, the photosensitive region corresponding to a channel can be changed through electrical control. Before each reception of the echo light, the corrector module141changes the photosensitive region (region of interest, “ROI”) to shift, to compensate for the inclination angle of the corresponding surface to be corrected. This ensures that each corresponding corrective detector unit receives echo light in a fixed channel field of view direction. For example, a field of view direction of an i-th channel corresponds to a vertical field of view direction of 40°, when a surface to be corrected 1 is at a first inclination angle, a readout data of a first corrective detector unit is used, and when a surface to be corrected 2 in a second inclination angle, a readout data of a second corrective detector unit is used, to ensure that both of the 2 corrective detector units corresponds to a vertical field of view direction of 40°, causing a receiving field of view of the LiDAR to remain stable at a fixed angle, and avoiding or decreasing detection angle fluctuation among the multiple reflection surfaces.

Specifically, as mentioned, the inclination angle of the surface to be corrected includes: a vertical inclination angle θ and a horizontal inclination angle ϕ; and in such a case, the corrector module141determines the multiple corrective detector units based on the vertical inclination angle θ and the horizontal inclination angle ϕ.

With reference toFIG.14, a schematic diagram of a light path in a vertical field of view of the embodiment of LiDAR shown inFIG.7is shown.

Both emitted detection light and received echo light are reflected by the surface to be corrected120ri, and the surface to be corrected120rihas an inclination angle, that is, there is an angle θibetween an ideal position and orientation120idiand an actual position and orientation120reiof the surface to be corrected120ri. A position of a reflection point of the echo light Rbin a field of view direction of the b-th channel (as shown by solid arrow Rband dotted arrow Rb′ in the figure, where the solid arrow Rband the dotted arrow Rb′ are parallel to each other, Rbshows echo light projected at the actual position and orientation120rei, and Rb′ shows echo light projected at the ideal position and orientation120idi) offsets on the surface to be corrected120ri(offset from point O′ at the ideal position and orientation120idito point O at the actual position and orientation120rei). In this case, an ideal detector unit131idbcannot receive the echo light in the field of view direction of the b-th channel. In this case, the ideal detector unit13lidbactually receives echo light in a field of view direction Rk′, there is an angle Δθ=2*θibetween the Rk′ and Rb′. The echo light in the field of view direction of the b-th channel is received by a corrective detector unit130chb.

Specifically,FIG.14shows a schematic light path in a vertical field of view.

The detector module130is located at a focal plane position of the optical receiving assembly Rx. Prior to compensation, an ordinate of a center position of a b-th ideal detector unit131idbis yb. b is the channel number, and a vertical field angle of a field of view of the b-th channel corresponding to the b-th ideal detector unit131idbis θb, that is, a vertical field angle of detection light emission corresponding to the echo light received by a b-th detector unit is:

f is the focal length of the optical receiving assembly Rx.

The corrector module141pre-stores n groups of inclination angles with one-to-one correspondence between the n reflection surfaces in the scanner module120and the n groups of inclination angles, and vertical inclination angles of the n reflection surfaces are θ1, θ2, . . . , θnrespectively. The vertical inclination angle corresponding to the surface to be corrected120riis θi. Both the emitted detection light and the received echo light are reflected by the surface to be corrected120ri. In such a case, an offset angle in a vertical direction of reflected light formed by reflection of the echo light Rbin the field of view direction of the b-th channel from the surface to be corrected120; is Δθ=2*θi, that is, a position of the light spot formed by the reflected light on the detector module130is translated by Δy=Δθ*f along a corresponding direction. In such a case, the difference Δy between an ordinate of a center position of the b-th corrective detector unit130chband an ordinate of the center position of the b-th detector unit is determined by the corrector module141. Moreover, a direction in which the center position of the b-th corrective detector unit points to the center position of the b-th detector unit is opposite to an offset direction of a reflection point position of the surface to be corrected120ri.

It can be seen that the corrective detector units determined by the corrector module141based on the inclination angle of the surface to be corrected reversely translate the region of interest in the detector module130by Δy. In such a case, for the b-th corrective detector unit131chb, a vertical field angle of detection light emission corresponding to the received echo light is

that is, equal to a corresponding field angle when the surface to be corrected120ridoes not have an inclination angle (vertical inclination angle θi=0).

With reference toFIG.15, a schematic diagram of a light path in a horizontal field of view of the embodiment of LiDAR shown inFIG.7is shown.

The compensation principle in the horizontal field of view is similar to the compensation principle in the vertical field of view.

Specifically,FIG.15shows a schematic light path in the horizontal field of view.

Prior to compensation, an abscissa of a center position of the b-th ideal detector unit131idbis xb, b is the channel number. A horizontal field angle of a field of view of the b-th channel corresponding to the b-th ideal detector unit131idbis ϕb, that is, a horizontal field angle of detection light emission corresponding to the echo light received by the b-th detector unit is:

f is the focal length of the optical receiving assembly Rx.

The corrector module141pre-stores n groups of inclination angles with one-to-one correspondence between the n reflection surfaces in the scanner module120and the n groups of inclination angles, and horizontal inclination angles of the n reflection surfaces are ϕ1, ϕ2, . . . , ϕnrespectively. The horizontal inclination angle corresponding to the surface to be corrected120riis ϕi. Both the emitted detection light and the received echo light are reflected by the surface to be corrected120ri. In such a case, an offset angle in a horizontal direction of reflected light formed by reflection of the echo light Rbin the field of view direction of the b-th channel from the surface to be corrected120riis Δϕ=2*ϕi, that is, a position of the light spot formed by the reflected light on the detector module130is translated by Δx=Δϕ*f along a corresponding direction. In such a case, the difference Δx between an abscissa of the center position of the b-th corrective detector unit130chband an abscissa of the center position of the b-th detector unit is determined by the corrector module141. Moreover, a direction in which the center position of the b-th corrective detector unit points to the center position of the b-th detector unit is opposite to an offset direction of a reflection point position of the surface to be corrected120ri.

It can be seen that the corrective detector units determined by the corrector module141based on the inclination angle of the surface to be corrected reversely translate the region of interest in the detector module130by Δx. In such a case, for the b-th corrective detector unit131chb, a horizontal field angle of detection light emission corresponding to the received echo light is

that is, equal to a corresponding field angle when the surface to be corrected120ridoes not have an inclination angle (horizontal inclination angle ϕi=0).

In such a case, the corrective detector unit determined by the corrector module141can compensate for the inclination angle of the surface to be corrected to ensure that the determined detector unit corresponds to a fixed field of view direction. Particularly when the scanner module includes multiple reflection surfaces, the corrector module141determines different corrective detector units based on respective inclination angles of the multiple reflection surfaces, to ensure that each of the reflection surfaces corresponds to a fixed field of view direction based on the determined corrective detector unit, causing inhibition of the occurrence of point cloud jitter among the multiple reflective surfaces.

It should be noted that the ideal detector unit, such as the b-th ideal detector unit131idbinFIGS.14and15, is a detector unit prior to compensation, that is, the detector unit131determined by calibration of the LiDAR inFIG.8. The ideal detector unit includes two or more of the detectors, and the two or more detectors in the ideal detector unit are at least partially different from multiple detectors in the corrective detector unit.

It should be further noted that, as mentioned, in some embodiments of this disclosure, the detector module130includes multiple detectors131ithat are independently powered on and independently read out. In such a case, the corrector module141changes a receiving region of a receiving array by powering only a detector on a specific address wire or reading only a signal of a detector on a specific address wire, to achieve the purpose of maintaining a stable field of view.

Further with reference toFIGS.8and11, in some embodiments of this disclosure, the light-emitter module110of the LiDAR includes multiple independently addressable and independently controlled lasers. In such a case, the corrector module141is further configured to determine multiple corrective light-emitter units based on the inclination angle of the surface to be corrected in combination with the multiple corrective detector units. There is a one-to-one correspondence between the multiple corrective light-emitter units and the multiple corrective detector units.

The one-to-one correspondence between the multiple corrective light-emitter units and the multiple corrective detector units means that a corrective light-emitter unit and a corresponding corrective detector unit have a same field of view angle in a far field, that is, in the far field, an emission field of view angle of the corrective light-emitter unit is equal to a receiving field of view angle of the corresponding corrective detector unit. Specifically, the corrector module141applies different voltages to connection wires of the emission array, to select different emitters to emit light.

It should be noted that a light emitter module110of the LiDAR includes multiple emitters. In such a case, each of the corrective light-emitter units includes two or more of the emitters. Based on the determination of the corrective light-emitter unit by the corrector module141, the receiving field of view angle of the corrective detector unit is the same as the emission field of view angle of the corrective light-emitter unit, to ensure the ranging capacity and the detection efficiency of the LiDAR.

Further with reference toFIG.1, the processor apparatus140further includes: a collector module142. The collector module142is configured to perform signal collection by the multiple corrective detector units to determine a point cloud image.

The collector module142includes a detection controller unit142a. The detection controller unit142ais configured to control the multiple corrective light-emitter units111′ to generate detection light. The detection light forms corresponding echo light after reflected by an object outside the LiDAR. The collector module142further includes a reception controller unit142b. The reception controller unit142bis configured to control a corresponding corrective detector unit to receive the echo light to collect signal.

Specifically, the detection light is emitted after reflected by the surface to be corrected; the emitted detection light forms echo light after reflected by an object outside the LiDAR; and the echo light is reflected by the surface to be corrected to the multiple corrective detector units. The surface to be corrected is one of the multiple reflection surfaces of the Because the corrective detector unit131is determined by the collector module142prior to signal collection, and the corrective detector unit131is determined based on the inclination angle of the surface to be corrected, that is, positions of the corrective detector unit131has been changed to compensate for the deflection caused by the inclination angle of the surface to be corrected, thereby achieving the effects of maintaining a stable field of view.

In addition, with reference toFIG.16, a schematic diagram of implementing signal collection by the corrective light-emitter units111′ and the corrective detector units131in the embodiment of the LiDAR shown inFIG.8is shown.

The corrective light-emitter unit111′ is determined based on the inclination angle of the surface to be corrected and the corrective detector unit131. In such a case, when a signal is emitted or received, the light spot on the receiving array is still located at a center position of the corrective detector unit131, that is, the corrective detector unit can receive all energy of an echo light spot in a field of view direction of a corresponding channel (the circle in the figure represents the light spot), to improve the detection efficiency and the ranging capacity.

It should be noted that, in other embodiments of this disclosure, as shown inFIG.17, the LiDAR includes a light-emitter module, the light-emitter module210includes: multiple light-emitter units211, and there is a one-to-one correspondence between the multiple light-emitter units211and the multiple corrective detector units231; the collector module142enables the multiple light-emitter units211to generate detection light, the detection light forms corresponding echo light after reflected by an object outside the LiDAR; and the collector module142receives the echo light by a corresponding corrective detector unit231to collect signal.

To sum up, the multiple corrective detector units are determined based on the pre-stored inclination angle of the surface to be corrected to compensate for the inclination angle of the reflection surface; and signal collection is performed by the multiple corrective detector units to determine a point cloud image. Because the multiple corrective detector units are determined based on the inclination angle of the surface to be corrected, the determination of the corrective detector unit can compensate for the inclination angle of the surface to be corrected to ensure that the determined corrective detector unit corresponds to a fixed field of view direction. Particularly when the scanner module includes multiple reflection surfaces, different corrective detector units are determined based on respective inclination angles of the multiple reflection surfaces, to ensure that each of the reflection surfaces corresponds to the fixed field of view direction based on the determined corrective detector unit, causing inhibition of the occurrence of point cloud jitter among the multiple reflective surfaces.

Moreover, after the multiple corrective detector units are determined, the multiple corrective light-emitter units are determined based on the inclination angle of the surface to be corrected in combination with the multiple corrective detector units, to perform signal collection by the corrective light-emitter unit and the corrective detector unit. The determination of the multiple corrective light-emitter units can make a receiving field of view of the corrective detector units correspond to a light spot center of the received echo light, to improve the detection efficiency and ensure long ranging distance.

Although this disclosure is disclosed as above, this disclosure is not limited to the above. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of this disclosure, and therefore the scope of protection of this disclosure shall be subject to the scope limited by the claims.