CN117849814A

CN117849814A - Non-coaxial laser radar system and configuration method thereof

Info

Publication number: CN117849814A
Application number: CN202211224156.9A
Authority: CN
Inventors: 杜欣; 王思拨; 舒博正; 赵拓; 夏冰冰; 石拓
Original assignee: Zvision Technologies Co Ltd
Current assignee: Zvision Technologies Co Ltd
Priority date: 2022-10-08
Filing date: 2022-10-08
Publication date: 2024-04-09

Abstract

The present disclosure provides a method for configuring a non-coaxial lidar system, a vehicle, an electronic device, and a storage medium and a program product. The method comprises the following steps: emitting, by the light emitter, a first ranging laser beam having a first emission angle; receiving, by a first receiving channel of the optical receiver, a first reflected beam of a first ranging laser beam reflected by the target object; in response to receiving the first reflected beam by the first receive channel, calculating a distance of the target object from the non-coaxial lidar system; calculating a first receiving angle of the light receiver for receiving the first reflected beam through coordinate conversion between the first coordinate system and the second coordinate system according to the first emitting angle and the distance; and selecting a second receiving channel for receiving a second reflected beam of the second ranging laser beam from among the plurality of receiving channels of the optical receiver according to the first receiving angles and the first correspondence between the plurality of receiving angles of the optical receiver and the plurality of receiving channels of the optical receiver.

Description

Non-coaxial laser radar system and configuration method thereof

Technical Field

The present disclosure relates to non-coaxial lidar systems, and more particularly to methods, non-coaxial lidar systems, vehicles, electronic devices, media, and program products for configuring non-coaxial lidar systems.

Background

LiDAR systems, also known as laser detection and ranging (LiDAR or LiDAR) systems, measure information, such as the position, velocity, etc., of a target object, such as an object, such as a vehicle or pedestrian, by transmitting a laser beam to the target object and receiving a reflected beam from the target object. The lidar system may include a coaxial lidar system and a non-coaxial lidar system, the distinction between the two being whether the laser transmitting system and the laser receiving system are relatively independent and whether a transmit path from a light source of the lidar to the target object is coaxial with a receive path from the target object to a light receiver of the lidar. Non-coaxial lidar systems may achieve at least a larger angular range of field of view than coaxial lidar systems. However, in the case of a non-coaxial lidar, as the distance between the target object and the lidar changes, the position of the spot on the light receiver of the light beam reflected from the target object may move. Thus, the light spot on the light receiver may partially leave the predetermined detector, thereby reducing the intensity of the detection signal. Further, as the distance between the target object and the lidar changes further, the light spot on the light receiver may completely leave the intended detector and move onto another detector, and thus be completely undetectable by the intended detector.

Therefore, it is necessary to cope with the case where the position of the spot on the light receiver of the light beam reflected from the target object moves as the distance between the target object and the laser radar changes, so that the measurement of the reflected beam is improved in order to adjust or optimize the measurement result of the laser radar system.

Disclosure of Invention

In order to address at least some of the above-mentioned drawbacks of current non-coaxial lidar systems, the present disclosure provides a method for configuring a non-coaxial lidar system, as well as a lidar system, a vehicle, an electronic device, and corresponding media and program products, capable of improving the measurement of reflected beams, achieving a better ranging effect.

One aspect of the present disclosure relates to a method for configuring a non-coaxial lidar system, comprising: emitting, by a light emitter, a first ranging laser beam having a first emission angle, the light emitter having a first coordinate system associated therewith; receiving, by a first receiving channel of an optical receiver, a first reflected beam of a first ranging laser beam reflected by a target object, the optical receiver having a second coordinate system associated therewith; in response to receiving the first reflected beam by the first receive channel, calculating a distance of the target object from the non-coaxial lidar system; calculating a first receiving angle of the light receiver for receiving the first reflected beam through coordinate conversion between the first coordinate system and the second coordinate system according to the first emitting angle and the distance; and selecting a second receiving channel for receiving a second reflected beam of the second ranging laser beam from the plurality of receiving channels of the optical receiver according to a first corresponding relation between the first receiving angle and the plurality of receiving angles of the optical receiver and the plurality of receiving channels of the optical receiver, the first corresponding relation being obtained by training the non-coaxial laser radar system in advance.

One aspect of the present disclosure relates to a method for configuring a non-coaxial lidar system, comprising: emitting, by a light emitter, a first ranging laser beam having a first emission angle, the light emitter having a first coordinate system associated therewith; receiving, by a first receiving channel of an optical receiver, a first reflected beam of a first ranging laser beam reflected by a target object, the optical receiver having a second coordinate system associated therewith; in response to receiving the first reflected beam by the first receive channel, calculating a distance of the target object from the non-coaxial lidar system; calculating a second receiving angle of a second reflected beam of the second ranging laser beam received by the light receiver through coordinate conversion between the first coordinate system and the second coordinate system according to a second emitting angle of the second ranging laser beam and the distance; and selecting a second receiving channel for receiving the second reflected beam from a plurality of receiving channels of the optical receiver according to the second receiving angle and a first corresponding relation between the plurality of receiving angles of the optical receiver and the plurality of receiving channels of the optical receiver, wherein the first corresponding relation is obtained by training the non-coaxial laser radar system in advance.

Another aspect of the disclosure relates to a non-coaxial lidar system. The lidar system comprises a light emitter configured to emit a plurality of ranging laser beams at different emission angles, and a light receiver configured to detect reflected beams of the ranging laser beams reflected by the target object, the light receiver having a plurality of receiving channels. The controller is communicatively coupled with the light source, the scanner, and the light receiver. The controller is configured to perform the method for configuring a lidar system as described above.

Another aspect of the present disclosure relates to a vehicle. The vehicle includes a lidar system and a vehicle controller. The vehicle controller is communicatively coupled with the lidar system. The vehicle controller is configured to perform the method for configuring a lidar system as described above.

Another aspect of the present disclosure relates to an electronic device. The electronic device includes a processor and a memory. The memory is communicatively coupled to the processor and stores computer readable instructions. The computer readable instructions, when executed by the processor, cause the electronic device to perform the method for configuring a lidar system as described above.

Another aspect of the disclosure relates to a computer-readable storage medium storing computer-readable instructions that, when executed by a processor of an electronic device, cause the electronic device to perform a method for configuring a lidar system as described previously.

Another aspect of the disclosure relates to a computer program product comprising computer readable instructions which, when executed by a processor of an electronic device, implement a method for configuring a lidar system as described before.

Drawings

The foregoing and other objects and advantages of the disclosure are further described below in connection with the following detailed description of the embodiments, with reference to the accompanying drawings. In the drawings, the same or corresponding technical features or components will be denoted by the same or corresponding reference numerals.

FIG. 1 shows a schematic composition diagram of a non-coaxial lidar system according to an embodiment of the present disclosure;

FIG. 2a shows an example of laser light emission point distribution when a non-coaxial lidar system performs a field of view scan according to an embodiment of the present disclosure;

FIG. 2b illustrates an example of a received field of view of a lidar system according to an embodiment of the disclosure;

fig. 2c shows a structural example of an optical receiver of a lidar system according to an embodiment of the present disclosure;

FIG. 2d illustrates an example of a laser light emission point and received field of view correspondence for a lidar system according to an embodiment of the disclosure;

FIG. 3 shows a schematic diagram of the variation in spot position on a receiver array of reflected beams of the same laser beam caused by target objects of different distances;

FIG. 4 shows a schematic diagram of spot positions on a receiver array of reflected beams of a plurality of laser beams having different emission angles reflected from target objects of different distances;

FIG. 5 illustrates a flow chart of a method 500 for configuring a lidar system according to an embodiment of the disclosure;

FIG. 6 shows a schematic diagram of a first coordinate system and a second coordinate system associated with an optical transmitter and an optical receiver, respectively, according to an embodiment of the disclosure;

FIG. 7 illustrates a flow chart of a method 700 for pre-training a non-coaxial lidar system according to an embodiment of the present disclosure;

FIG. 8 illustrates a flow chart of a method 800 for configuring a lidar system according to an embodiment of the disclosure;

FIG. 9 illustrates a flow chart of a method 900 for configuring a lidar system according to another embodiment of the disclosure;

FIG. 10 illustrates a schematic composition of a vehicle incorporating a lidar system according to an embodiment of the present disclosure; and is also provided with

Fig. 11 shows a block diagram of a configuration of an electronic device according to an embodiment of the present disclosure.

Detailed Description

The following detailed description is made with reference to the accompanying drawings and is provided to assist in a comprehensive understanding of various example embodiments of the disclosure. The following description includes various details to aid in understanding, but these are to be considered merely examples and are not intended to limit the disclosure, which is defined by the appended claims and their equivalents. The words and phrases used in the following description are only intended to provide a clear and consistent understanding of the present disclosure. In addition, descriptions of well-known structures, functions and configurations may be omitted for clarity and conciseness. Those of ordinary skill in the art will recognize that various changes and modifications of the examples described herein can be made without departing from the scope of the disclosure.

Fig. 1 illustrates an exemplary lidar system 100 to which the techniques of the present disclosure may be applied. Lidar system 100 may include an optical transmitter 101, an optical receiver 106, and a controller 108.

The light emitter 101 includes a light source 102 and a scanner 104. The light source 102 emits an emission beam for scanning the target object 120. The light source 102 may be a laser, for example, a solid state laser such as a Vertical Cavity Surface Emitting Laser (VCSEL) or an external cavity semiconductor laser (ECDL), a laser diode, a fiber laser. The light source 102 may also include an LED. The light source 102 may emit light beams of different forms, including pulsed light, continuous light (CW), and quasi-continuous light. The operating wavelength of the light source may be 650nm to 1150nm, 800nm to 1000nm, 850nm to 950nm, or 1300nm to 1600nm. In one or more embodiments, the light source 102 may further include an optical assembly optically coupled to the light source 102 for collimating or focusing the light beam emitted by the light source 102. Each emitted light beam emitted by the light source 102 may be continuous light for a certain time or may be one or more light pulses.

The scanner 104 is configured to deflect the direction of the emitted light beam from the light source 102 to scan the target object 120 for a wider emitted or scanned field of view. The scanner 104 may have any number of optical mirrors driven by any number of drivers. For example, the scanner 104 may include a planar mirror, a prism, a mechanical galvanometer, a polarization grating, an Optical Phased Array (OPA), a microelectromechanical system (MEMS) galvanometer. For MEMS galvanometers, the mirror surface is rotated or translated in one or two dimensions under electrostatic/piezoelectric/electromagnetic actuation. Under drive of the driver, the scanner 104 directs the light beam from the light source to various locations within the field of view to effect scanning of the target object 120 within the field of view.

In one or more embodiments, the light emitter 101 of the lidar system 100 may also include an emission lens 110. The emission lens 110 may be used to expand the light beam emitted by the light source 102 and diverted by the scanner 104. The emission lens 110 may include a Diffractive Optical Element (DOE) for shaping, separating, or diffusing the light beam. The emission lens 110 may be present alone or may be integrated into other components (e.g., the scanner 104 or the light source 102). The position of the emission lens 110 in the emission light path from the light source to the target object is not limited to that shown in fig. 1, but may be changed to other positions. For example, an emission lens may be disposed between the light source 102 and the scanner 104 such that the light beam emitted by the light source 102 is first expanded by the emission lens and then diverted by the scanner.

After reflecting off target object 120, a portion of the reflected light (or echo signal) returns to lidar system 100 and is received by light receiver 106. The light receiver 106 receives and detects a portion of the reflected light from the target object 120 and generates a corresponding electrical signal. The target object may be any object within the scanning field of view of the lidar that is capable of reflecting the scanning laser light, such as a vehicle, a pedestrian, an animal, a guideboard, an obstacle, a tree, a shelf, furniture, etc. The optical receiver may include a receiving unit and associated receiving circuitry. Each receiving circuit may be adapted to process the output electrical signal of the corresponding receiving unit. The receiving unit comprises various forms of photodetectors or one-dimensional or two-dimensional arrays of photodetectors, and accordingly the receiving circuit may be a circuit or an array of circuits. The photodetector measures the power, phase or time characteristics of the reflected light and produces a corresponding current output. The photodetector may be an avalanche diode (APD), single Photon Avalanche Diode (SPAD), PN photodiode, or PIN photodiode.

The controller 108 is communicatively coupled to one or more of the light source 102 and the scanner 104 of the light emitter 101 and the light receiver 106. The controller 108 may control whether and when the light source 102 emits a light beam. The controller 108 may control the scanner 104 to scan the light beam to a specific location. The controller 108 may process and analyze the electrical signals output by the optical receiver to ultimately determine the position, velocity, etc. characteristics of the target object 120. The controller 108 may include an Integrated Circuit (IC), an Application Specific Integrated Circuit (ASIC), a microchip, a microcontroller, a central processing unit (cpu), a Graphics Processing Unit (GPU), a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA), or other suitable circuitry for executing instructions or performing logic operations. The instructions executed by the controller 108 may be preloaded into an integrated or separate memory (not shown). The memory may store configuration data or commands for the light source 102, the scanner 104, or the light receiver 106. The memory may also store the electrical signal output from the optical receiver 106 or an analysis result based on the output electrical signal. The memory may include Random Access Memory (RAM), read Only Memory (ROM), hard disk, optical disk, magnetic disk, flash memory or other volatile or non-volatile memory, and the like. The controller 108 may include a single or multiple processing circuits. In the case of multiple processing circuits, the processing circuits may have the same or different configurations and may interact or cooperate with each other electrically, magnetically, optically, acoustically, mechanically, etc.

After detecting the reflected light, the controller 108 of the lidar system may calculate the distance of the target object from the time of flight, calculate the reflectivity of the target object from the intensity and the distance of the reflected light, and calculate the spatial position of the target object from the deflection position/angle of the scanner when the scanning beam is emitted, thereby obtaining a three-dimensional measurement result of the target object.

In one or more embodiments, lidar system 100 may also include a receive lens 112 and a stop 113. The receiving lens 112 and the diaphragm 113 are located before the light receiver 106 on the receiving path of the emitted light from the target object 120 to the light receiver 106. The receiving lens 112 may include an imaging system lens such that the focal point of the reflected beam is either in front of or behind the detection surface of the photodetector or photodetector array or is located directly above the detection surface. In some cases, instead of being present as a separate component, the receiving lens 112 may also be integrated into the optical receiver 106. The diaphragm 113 is used to limit the angle of incident light incident on the light receiver 106, block stray light, and the like.

Lidar system 100 of the present application is a non-coaxial lidar system. As shown in fig. 1, the reflected beam reaches the light receiver 106 without returning to the scanner 104, the laser transmitting system and the laser receiving system are independent, and the transmitting path from the light source of the laser radar to the target object is non-coaxial with the receiving path from the target object to the light receiver of the laser radar.

In one or more embodiments, lidar system 100 may also include a housing 114 for enclosing one or more of the foregoing components therein for protection. In some embodiments, the housing 114 is an opaque material, and a transparent area or window 116 may be provided in the housing 114 to allow the emitted or reflected light beam to pass through. In other embodiments, the housing 114 itself is a transparent material, thereby allowing the emitted or reflected light beam to pass through any location.

The lidar system may control the scanner to direct the emitted beam in a predetermined scanning pattern. Typically, the scanner spatially presents a closed scan pattern as it scans, and periodically repeats the scan. Common scan patterns include line and column raster, lissajous patterns, spiral patterns, and the like. Fig. 2a shows an example of a cloud of laser points when the lidar system is scanned in a line and column raster scan pattern. Each pixel point 204 in the point cloud represents a position in the emission field (or scan field) where the scanner directs an emission beam. The aggregate set of all pixels 204 forms the field of view 202 of the lidar system. The emission field of view 202 may have a variety of different shapes depending on the predetermined scan pattern, and is not limited to the rectangular shape shown in fig. 2 a. Each pixel 204 may be associated with one or more emitted light beams or one or more measurements.

Fig. 2b shows an example of a receive field of view distribution of a lidar system comprising a non-coaxial optical transceiver system. In this example, the lidar system includes a receiver array of a plurality of receive sub-modules arranged along at least one direction, each receive sub-module including one or more receive units and their respective receive circuits. Each receiving sub-module is capable of receiving reflected light over a relatively small range. For example, each rectangle 208 in FIG. 2b represents the range of reflected light that a respective one of the receiving sub-modules of the lidar system is capable of receiving, also referred to as the receiving field of view of the respective receiving sub-module. The aggregate of the receive fields of view of all the receive sub-modules constitutes the total receive field of view 206 of the optical receiver.

Fig. 2c shows a schematic composition of an optical receiver in order to provide the receiving field of view lidar system of fig. 2 b. The optical receiver includes an array of one or more receiving units 210 and corresponding one or more receiving circuits 214. The receiving units 210 are connected to respective receiving circuits 214 through electrical connections 212. For example, the receive field of view 208 in fig. 2b corresponds to the receive sub-module of the receive unit 216 and corresponding receive circuitry 218 in fig. 2 c.

Fig. 2d shows an example of the correspondence between the laser emission and reception fields of view in operation of the lidar system with the scanning laser point cloud of fig. 2a and the reception field of view of fig. 2 b. During operation, with the deflection of the scanner, the emitted light beam is directed to different positions in the emitted view field, and the controller instructs the receiving sub-module corresponding to the position in the receiving view field in the light receiver to be started so as to receive the reflected light beam, so that measurement is completed. For example, pixel 218 may correspond to pixel 204 in FIG. 2a and receive field of view 220 may correspond to receive field of view 208 in FIG. 2 b. When the lidar system generates a transmitted beam directed at the pixel 218, the receiving sub-module corresponding to the receiving field of view 220 needs to be turned on, i.e. the receiving sub-module comprising the receiving unit 216 and the receiving circuit 218 in fig. 2c may be turned on. The receiving sub-modules of the optical receiver other than the receiving sub-module corresponding to the receiving field of view 220 may be turned off or dormant.

It should be appreciated that the transmit field of view, receive field of view, and corresponding receive sub-module distribution shown in fig. 2 a-2 d are merely illustrative. The lidar system according to the present disclosure may have different scan patterns, transmit fields of view, receive field of view distributions, shapes, numbers and distributions of receive sub-modules, and correspondence of transmit fields of view and receive fields of view.

Furthermore, the receiver arrays shown in fig. 2a to 2d are schematic and the number and density of receiving sub-modules in the receiver arrays may be greater than shown in the figures.

Fig. 3 shows a schematic diagram of the variation of spot position on the receiver array of the reflected beam of the same laser beam caused by target objects of different distances.

As shown in fig. 3 (a), the same laser beam emitted from the emission lens 110 is irradiated onto and reflected by target objects separated by a distance 1, a distance 2, and a distance 3, respectively, from the lidar system. As shown, distance 1 is less than distance 2, and distance 2 is less than distance 3. The reflected beam reflected from the target object is received by the receiving lens 112 and is incident on the light receiver 106 through the diaphragm 113. As shown, the laser beam incident on the target object located at the distance 1 and the reflected beam reflected from the target object are indicated by solid lines. Similarly, a laser beam incident on a target object located at a distance 2 and a reflected beam reflected from the target object are indicated by broken lines, and a laser beam incident on a target object located at a distance 3 and a reflected beam reflected from the target object are indicated by dashed-dotted lines.

As shown in fig. 3 (a), the spot positions of the reflected beams reflected from the target objects located at the distances 1, 2, and 3 are changed on the receiver array. Specifically, as the distance of the target object increases, the spot position of the reflected beam on the receiver array moves toward the optical axis of the ranging laser beam.

Fig. 3 (b) shows a partial enlarged view of the light receiver 106, which shows a plurality of receiving units 210, wherein at least three receiving units are capable of receiving reflected beams reflected from target objects located at distances 1, 2, and 3, respectively. Specifically, the lower receiving unit corresponds to the receiving channel a, and receives the reflected beam reflected from the target object located at the distance 1. The light spot of the target object of distance 1 in fig. 3 (b) is indicated by a solid circle. Furthermore, the intermediate receiving unit corresponds to the receiving channel b, and receives the reflected beam reflected from the target object located at the distance 2. The spot of the target object of distance 2 in fig. 3 (b) is represented by a dotted circle. In addition, the lower receiving unit corresponds to the receiving channel c, and receives the reflected beam reflected from the target object located at the distance 3. The spot of the target object of distance 3 in fig. 3 (b) is indicated by a dot-dash circle.

As shown in (b) of fig. 3, the spots of the laser beam reflected by the target object at the distance 1 are all incident on the receiving unit of the channel a, and thus the receiving unit of the channel a can generate the detection signal of the spot at the distance 1, while the receiving units of the channel b and the channel c cannot generate the detection signal of the spot at the distance 1. Further, the spot of the laser beam reflected by the target object at the distance 2 is mostly incident on the receiving unit of the channel b and a small part is incident on the receiving unit of the channel c, and the detection signal of the spot of the distance 2 generated by the receiving unit of the channel b is larger than the detection signal of the spot of the distance 2 generated by the receiving unit of the channel c, whereas the receiving unit of the channel a cannot generate the detection signal of the spot of the distance 1. Furthermore, the spots of the laser beam reflected by the target object at the distance 3 are all incident on the receiving unit of the channel c, and thus the receiving unit of the channel c can generate the detection signal of the spot at the distance 3, whereas the receiving units of the channel a and the channel b cannot generate the detection signal of the spot at the distance 3.

Thus, for a laser beam emitted at the same emission angle, as the distance of the target object changes, the angle of reception of the reflected beam received by the light receiver, which is reflected back from the target object, may also change and further cause a change in the reception channel on the light detector, which receives the reflected beam.

Fig. 4 shows a schematic diagram of spot positions on a receiver array of reflected beams of a plurality of laser beams having different emission angles reflected from target objects of different distances.

Similar to fig. 3, the three laser beams emitted from the emission lens 110 in fig. 4 are irradiated onto and reflected by target objects separated by a distance 1, a distance 2, and a distance 3 from the lidar system, respectively.

However, unlike fig. 3, the three laser beams in fig. 4 have different emission angles. Specifically, as shown in fig. 4 (a), the emission angles of the laser beams irradiated to the target objects at the distances 1, 2, and 3 are sequentially reduced, and by setting the specific three emission angles, the spot positions of the three reflected beams reflected from the target objects located at the distances 1, 2, and 3 are substantially coincident on the receiver array, respectively. Fig. 4 (b) shows a partial enlarged view of the light receiver 106, which shows that the light spots from the target objects of distance 1, distance 2 and distance 3 are incident on the receiving unit of the channel c and substantially coincide with each other. In this case, the receiving units of channel c may generate detection signals for the spots of distance 1, distance 2 and distance 3, whereas the receiving units of channel a and channel b may not generate detection signals.

As can be seen from comparing fig. 3 and 4, for a target object at the same distance, as the emission angle of the laser beam emitted by the emission angle changes, the reception angle of the reflected beam received by the light receiver, which is reflected back from the target object, may also change, and further cause a change in the reception channel on the light detector, which receives the reflected beam. Further, as can be seen from fig. 4, when the reception angles of the reflected beams received by the light receiver and reflected back from the target object are the same, the emission angles of the laser beams emitted by the light emitters may be different.

Further, as can be seen from fig. 3 and 4, even if the distance of the target object and the emission angle of the laser beam are changed, when the reception angle of the reflected beam is the same, the position of the spot of the reflected beam on the photodetector is the same, and the corresponding reception channel is the same. In other words, the correspondence between the acceptance angle of the reflected beam and the acceptance channel is kept substantially fixed. As shown in fig. 3 and 4, the reflected beams from the target object all pass through the receiving aperture 105 of the light receiver 106 into the light receiver, and the position of the receiving aperture 105 with respect to the receiving sub-module of the light receiver 106 is fixed. Thus, reflected beams passing through the receiving aperture 105 along the same receiving angle may be incident on the same location of the optical receiver 106. In embodiments of the present application, the receiving aperture 105 may be provided by a diaphragm 113.

In the embodiment of the present application, the correspondence between the reception angle of the reflected beam and the reception channel may be predetermined. Thus, upon receiving the reflected beam, the receiving channel irradiated by the spot of the reflected beam can be determined based on the receiving angle of the reflected beam and the correspondence between the receiving angle and the receiving channel, and the receiving channel can be selected as the optimal receiving channel to receive the reflected beam.

A method 500 of configuring a non-coaxial lidar system according to the present application is described below in connection with fig. 5. Fig. 5 shows a flow chart of a method 500 for configuring a lidar system. The method 500 may be performed in the lidar system 100 of fig. 1. The method 500 begins at block 502 where a first ranging laser beam having a first emission angle is emitted by a light emitter of a non-coaxial lidar system. The laser may be controlled by a controller 108 of the lidar system 100 communicatively coupled thereto. One ranging beam is one laser spot in the field of view (cloud of laser spots) of the emission as the lidar system scans.

In the present application, the light emitter 101 has a first coordinate system (X _t ，Y _t ，Z _t ). Fig. 6 illustrates a first coordinate system (X _t ，Y _t ，Z _t ) Is a schematic diagram of (a). As shown in fig. 6, a first coordinate system (X _t ，Y _t ，Z _t ) Is a rectangular coordinate system of the transmitting end. In one embodiment of the present disclosure, the first coordinate system may beThe definition is as follows: the emission point of the light emitter 101 is the origin of coordinates O _t Y is arranged right in front of the field of view of the laser radar _t Axis, vertical radar field of view Y _t Axis and horizontally right X _t Axis, vertical X _t Y _t The plane is Z _t A shaft.

As shown in fig. 6, a first ranging laser beam O emitted by a light emitter 101 toward a target object T _t T may be an mth point in the field of view of the laser radar, and the first ranging laser beam has a first emission angle (azimuth angle alpha _t，m Pitch angle beta _t，m ). In the first coordinate system, the azimuth angle alpha is the position of the ranging laser beam in X _t Y _t From Y in plane _t Angle of axis deviation, i.e. first distance measuring laser beam O _t T is X _t Y _t Projection in plane with Y _t The angle formed by the shaft. In addition, pitch angle beta is the distance measuring laser beam Z _t Angle of axis deviation, i.e. first distance measuring laser beam O _t T and Z _t The angle formed by the shaft. Furthermore, the target object T is in a first coordinate system with the origin O _t Distance R between _t，m Can be calculated according to the distance between the target object and the laser radar.

Thus, in the first coordinate system, the position of the target object T may be expressed in the form of polar coordinates (R _t，m ，α _t，m ，β _t，m ) And rectangular form (x _t，m ，y _t，m ，z _t，m )。

Thereafter, at block 504, a first reflected beam of the first ranging laser beam reflected by the target object is received by a first receive channel of an optical receiver.

In this application, the optical receiver 106 has associated therewith a second coordinate system (X _r ，Y _r ，Z _r ). Fig. 6 also shows a second coordinate system (X _r ，T _r ，Z _r ) Is a schematic diagram of (a). As shown in fig. 6, a second coordinate system (X _r ，Y _r ，Z _r ) Is a rectangular coordinate system of the receiving end. In one of the present disclosureIn an embodiment, the second coordinate system may be defined as: the receive aperture 105 is centered at the origin of coordinates O _r Right in front of the light receiver 106 is Y _r An axis parallel to the array receiving array of the receiving unit 210 of the light receiver in the direction X _r Axis, vertical X _r Y _r The direction of the plane is Z _r A shaft.

As shown in fig. 6, the first ranging laser beam O reflected from the target object T received by the light receiver _t First reflected beam TO of T _r . The first reflected beam has a first angle of reception (azimuth angle alpha _r，m Pitch angle beta _r，m ). In the second coordinate system, the azimuth angle alpha is the distance measuring laser beam in X, similar to the first coordinate system _r Y _r From Y in plane _r Angle of axis deviation, i.e. first reflected beam TO _r At X _r Y _r Projection in plane with Y _r The angle formed by the shaft. In addition, pitch angle β is the reflected beam from Z _r Angle of axis deviation, i.e. first reflected beam TO _r And Z is _r The angle formed by the shaft. Furthermore, the target object T is in the second coordinate system with the origin O _r Distance R between _r，m Can be calculated according to the distance between the target object and the laser radar.

Thus, in the second coordinate system, the position of the target object T may be expressed in the form of polar coordinates (R _r，m ，α _r，m ，β _r，m ) And rectangular form (x _r，m ，y _r，m ，z _r，m )。

The first reception channel may be predetermined according to the first transmission angle. In embodiments of the present disclosure, the correspondence between the first receiving channel and the first transmitting angle may be obtained by training the non-coaxial lidar system in advance. Pre-training a non-coaxial lidar system is described in further detail below. Furthermore, other solutions are conceivable to the person skilled in the art for determining the first receiving channel from the first transmitting angle.

Thereafter, at block 506, a distance of the target object from the non-coaxial lidar system is calculated in response to receiving the first reflected beam by the first receive channel.

Referring to fig. 6, in case that the first receiving channel is capable of receiving the first reflected beam, the length (R _t，m ) Length (R) of the first reflected beam _r，m ) And (3) summing. On the basis of this, since the relative positional relationship of the first coordinate system and the second coordinate system is fixed, the length (R _t，m ) Length (R) of the first reflected beam _r，m ) The difference is fixed and can be predetermined. Thus, the length (R) of the first ranging laser beam can be determined from the flight time of the ranging laser beam _t，m ) Length (R) of the first reflected beam _r，m ). In this case, the length (R _t，m ) As the distance of the target object from the lidar system.

Furthermore, in another embodiment of the present disclosure, since the first coordinate system is very close to the second coordinate system and/or the difference in length of the ranging laser beam and the reflected beam is small enough to be ignored with respect to the distance of the target object, the length of the first ranging laser beam (R _t，m ) Length (R) of the first reflected beam _r，m ) Substantially equal, and both equal to half the distance traveled by the laser beam from the optical transmitter to the optical receiver. In this case, the length (R _t，m ) And the length (R) _r，m ) Is equal to the distance of the target object from the laser radar system.

Thereafter, at block 508, a first acceptance angle at which the optical receiver receives the first reflected beam is calculated from a first acceptance angle and the distance by coordinate conversion between the first coordinate system and the second coordinate system.

For a given non-coaxial lidar, since the relative positions of the light emitter 101 and the light receiver 106 are related to the structure of the lidar and are fixed, a first coordinate system (X _t ，Y _t ，Z _t ) And a second coordinate system (X _r ，Y _r ，Z _r ) Relative positional relationship between the two.

In an embodiment of the present disclosure, a first coordinate system (X _t ，Y _t ，Z _t ) And a second coordinate system (X _r ，Y _r ，Z _r ) The following positional relationship is provided: a second coordinate system (X _r ，T _r ，Z _r ) Is the origin of coordinates O of _r (center of diaphragm 113) in a first coordinate system (X _t ，Y _t ，Z _t ) The coordinates of (x) ₀ ，y ₀ ，Z ₀ ) And a second coordinate system (X _r ，Y _r ，Z _r ) Coordinate axis X of (2) _r 、Y _r And Z _r Around a first coordinate system (X _t ，Y _t ，Z _t ) X of (2) _t Axis, Y _t Axis, Z _t The rotation angles of the shafts are respectively theta ₁ 、θ ₂ 、θ ₃ 。

For a given non-coaxial lidar, the above parameter x ₀ 、y ₀ 、z ₀ 、θ ₁ 、θ ₂ 、θ ₃ Are known.

As will be appreciated by those skilled in the art, the above parameter x ₀ 、y ₀ 、z ₀ 、θ ₁ 、θ ₂ 、θ ₃ Can be determined according to actual conditions, and x ₀ 、y ₀ 、z ₀ At least one of which is non-zero to achieve non-coaxial characteristics of the lidar, θ ₁ 、θ ₂ 、θ ₃ May be all zero.

Referring to fig. 6, it will be apparent to those skilled in the art that the polar coordinates (R _t，m ，α _t，m ，β _t，m ) Can be converted into rectangular coordinates (x _t，m ，y _t，m ，z _t，m )：

Further, referring to the first coordinate system (X _t ，Y _t ，Z _t ) And a second coordinate system (X _r ，Y _r ，Z _r ) Relative positional relationship between the two, rectangular coordinates (x _t，m ，y _t，m ，z _t，m ) Can be translated into rectangular coordinates (x) in the auxiliary coordinate system by the following coordinate system translation formula _tr ，y _tr ，z _tr ) The coordinate axes of the auxiliary coordinate system are parallel to the coordinate axes of the first coordinate system respectively, but the origin coincides with the second coordinate system:

in the above formula, (x) as described above ₀ ，y ₀ ，z ₀ ) For the second coordinate system (X _r ，Y _r ，Z _r ) Is the origin of coordinates O of _r (center of diaphragm 113) in a first coordinate system (X _t ，Y _t ，Z _t ) Is a coordinate of (b) a coordinate of (c).

Rectangular coordinates (x) _tr ，y _tr ，z _tr ) The rectangular coordinates (x) in the second coordinate system are obtained by rotating the following coordinate system rotation formula _r，m ，y _r，m ，z _r，m )：

In the above formula, the symbols represent matrix multiplication, R ₁ 、R ₂ 、R ₃ A rotation matrix for converting the first coordinate system into the second coordinate system when the second coordinate system rotates around the X axis, the Y axis and the Z axis relative to the first coordinate system, and is identical to the theta ₁ 、θ ₂ 、θ ₃ And (5) associating. Further, R ₁ 、R ₂ 、R ₃ The specific expression of (2) is:

Further, on the basis of this, rectangular coordinates (x _r，m ，y _r，m ，z _r，m ) Can be converted into polar coordinates (R by the following formula _r，m ，α _r，m ，β _r，m )：

Due TO the first reflected beam TO _r Is to connect the target object T and the origin O in the second coordinate system _r Thus the first reflected beam TO can be determined based on the polar coordinates of the target object T in the second coordinate system _r Is of the first angle of reception (azimuth angle alpha _r，m Pitch angle beta _r，m )。

Furthermore, those skilled in the art will appreciate that although the above calculation formula providesBut R is an expression of (1) _r，m Or may be calculated in the previous block 506 without the need for calculation in block 508. In addition, in another embodiment of the present disclosure, R may not be calculated _r，m 。

Furthermore, according to the actual situation, when parameter x ₀ 、y ₀ 、Z ₀ 、θ ₁ 、θ ₂ 、θ ₃ The above calculation formula can be further simplified when one or more of them is zero, so that the calculation complexity can be reduced. Thus, the parameter x can be adjusted when designing a non-coaxial lidar system ₀ 、y ₀ 、z ₀ 、θ ₁ 、θ ₂ 、θ ₃ To reduce computational complexity.

Those skilled in the art will appreciate that other ways of transforming coordinates between the first coordinate system and the second coordinate system may be used and that these solutions are also included in the present application.

Thereafter, at block 510, a second receive channel for receiving a second reflected beam of a second ranging laser beam is selected from the plurality of receive channels of the optical receiver according to a first correspondence between the first receive angle and the plurality of receive angles of the optical receiver and the plurality of receive channels of the optical receiver. The first correspondence is obtained by training the non-coaxial lidar system in advance.

In an embodiment of the present disclosure, the first correspondence between the plurality of receiving angles of the optical receiver and the plurality of receiving channels of the optical receiver includes the plurality of receiving angles and the receiving channel in one-to-one correspondence with each of the plurality of receiving angles. The first correspondence may include, for example, a plurality of reception angles stored in a look-up table, map, or text manner, and an optimal reception channel corresponding to each reception angle.

In this embodiment, in response to receiving the first reflected beam by the first receive channel, a first receive angle is calculated, a closest receive angle to the calculated first receive angle of the plurality of receive angles may be determined, and a corresponding receive channel corresponding to the closest receive angle is selected as the second receive channel.

In this embodiment, based on the calculated reception angle (α _r，m ，β _r，m ) And searching the optimal receiving channel in the channel table according to the first corresponding relation. In an embodiment of the present application, a nearest neighbor search method is as follows:

wherein,representing traversing each acceptance angle in the first correspondence, looking up the acceptance angle (alpha) calculated with the mth point _r，m ，β _r，m ) The closest angle. After the angle is found, the corresponding receiving channel is selected as the final selected channel.

In another embodiment of the present disclosure, the first correspondence between the plurality of acceptance angles of the optical receiver and the plurality of acceptance channels of the optical receiver includes the plurality of acceptance channels and a strongest acceptance angle range for each of the plurality of acceptance channels. The strongest reception angle range of a reception channel refers to that for a reflected beam received at a reception angle within the strongest reception angle range, the signal strength detected by that reception channel is greater than or equal to the signal strengths detected by the other reception channels, i.e. the reception channel is the best reception channel for all reception angles within the reception angle range.

In this embodiment, in response to receiving the first reflected beam by the first receive channel, a first receive angle is calculated, and a receive channel of the plurality of receive channels having a strongest receive angle range including the calculated first receive angle may be selected as the second receive channel.

The range of reflection angles of the reflected beams that each receiving channel can receive (hereinafter referred to as the normal receiving angle range) tends to be larger than the strongest receiving angle range of that receiving channel. In other words, when the range of the reflection angle of the reflected beam is within the normal reception angle range of one reception channel, the signal intensity of the reflected beam is higher than a predetermined threshold or the signal-to-noise ratio thereof is higher than a predetermined threshold, and thus is sufficient to be detected by the reception channel. Thus, the normal acceptance angle range of each acceptance channel is wider than and includes its strongest acceptance angle range. Thus, when a receive channel is capable of receiving a first reflected beam, it is stated that the receive angle is within the normal receive angle range of the receive channel, but it is not stated whether the receive angle is within the strongest receive angle range of the receive channel.

Thus, in this embodiment, for example, where the first acceptance angle is within the strongest acceptance angle range of the first acceptance channel, the first acceptance channel may be selected to continue as the second acceptance channel receiving the second reflected beam of the second ranging beam.

In addition, in the case where the first reception channel is capable of receiving the first reflected beam and the first reception angle is out of the strongest reception angle range of the first reception channel, it is explained that the first reception angle is in a range of the normal reception angle range that does not overlap with the strongest reception angle range. In this case, a receiving channel having the strongest receiving angle range including the first receiving angle among the plurality of receiving channels may be selected as the second receiving channel that receives the second reflected beam of the second ranging beam.

In an embodiment of the present disclosure, the second ranging laser beam refers to a ranging laser beam emitted by a non-coaxial laser radar system after the current ranging laser beam (first ranging laser beam).

In one embodiment, the second ranging laser beam may be the next ranging laser beam in the same emission field of view as the first ranging laser beam. For example, the emission angles of a plurality of adjacent ranging laser beams in the same emission field of view of the lidar system are relatively close and the time interval is short, so that the plurality of adjacent ranging laser beams can be reflected by the same target object and the distance between the target object and the lidar system varies less between the plurality of ranging lasers. Thus, the angle of reception of the first ranging laser beam is typically relatively close to the angle of reception of the second ranging laser beam, falls on the same receiving unit, and is adapted to be received by the same receiving channel. This is particularly true for higher resolution lidar systems. Accordingly, the second reception channel for receiving the second reflected beam of the second ranging laser beam may be selected according to the first reception angle of the first ranging laser beam and the first correspondence between the plurality of reception angles of the optical receiver and the plurality of reception channels of the optical receiver.

In another embodiment, the second ranging laser beam may be a ranging laser beam of the same emission direction in a next emission field of view after the current emission field of view of the lidar. One transmit field of view may correspond to one frame in the range image of the lidar, and thus the second range laser beam may be a range laser beam corresponding to an adjacent next pixel in the same frame of the lidar. Since the time interval between the respective emission fields (frames) of the lidar system is short, the ranging laser beam of the same emission angle in the consecutive multiple emission fields (frames) can be reflected by the same target object and the distance between the target object and the lidar system varies less in the multiple frames. Thus, the angle of reception of the first ranging laser beam is typically relatively close to the angle of reception of the second ranging laser beam, falls on the same receiving unit, and is adapted to be received by the same receiving channel. This is particularly true for lidar systems that scan at higher frame rates. Also, a second reception channel for receiving a second reflected beam of the second ranging laser beam may be selected according to a first reception angle of the first ranging laser beam and a first correspondence between a plurality of reception angles of the optical receiver and a plurality of reception channels of the optical receiver.

Accordingly, one skilled in the art can take the above laser beam or other laser beam as a subsequent ranging laser beam according to the needs and the characteristics of the laser radar system used.

In the present application, by the above technical scheme, the receiving channel of the second ranging laser beam may be selected based on the receiving angle and the receiving channel of the first ranging laser beam, so that the receiving channel having the strongest ranging range may be used when ranging using the second ranging laser beam. Thereby, the problem of spot movement on the light receiver can be solved and the accuracy of measurement is further improved.

In the method 500 for configuring a lidar system of an embodiment of the present disclosure, as shown in block 501, a step of pre-training a non-coaxial lidar system may also be included. Next, a method 700 for pre-training a non-coaxial lidar system is described with reference to fig. 7. Fig. 7 shows a flow chart of a method 700 for pre-training a non-coaxial lidar system. The method 700 may be performed in the lidar system 100 of fig. 1 for a preset target object having a known distance. Method 700 begins at block 702 where a plurality of training laser beams having different training emission angles are respectively emitted by a light emitter of a non-coaxial lidar system being trained.

Assume that there are N scan points in the field of view 202 of the lidar system, each scan point corresponding to a laser firing angle (α _t ，β _t ). Thus, the light emitter 101 of the non-coaxial lidar system may emit N training laser beams having different N emission angles. Furthermore, similar to what has been described above with reference to fig. 6, the light emitter 101 of the non-coaxial lidar system has associated therewith a first coordinate system (X _t ，Y _t ，Z _t ) The optical receiver 106 has associated therewith a second coordinate system (X _r ，T _r ，Z _r ). The nth training laser beam emitted by the light reflector has a training emission angle (azimuth angle alpha _t，n Pitch angle beta _t，n ) And is reflected by the target object at a predetermined distance R.

Thereafter, at block 704, a plurality of training reflected beams of a plurality of training laser beams reflected by a preset target object are received by a plurality of receiving channels of the light receiver 106, respectively.

Assuming that the training reception angle of the nth training reflected beam is azimuth angle alpha _r，n Pitch angle beta _r，n . Similar to what was described above with reference to block 508 of fig. 5 and fig. 6, the reception angle (α _r，n ，β _r，n ) Is based on the training emission angle (alpha) _t，n ，β _t，n ) And a known distance R calculated by coordinate conversion between the first coordinate system and the second coordinate system. For brevity, the process of transmitting the light from the training emission angle (alpha _t，n ，β _t，n ) To training reception angle (alpha) _r，n ，β _r，n ) Is a conversion formula of (a).

It is assumed that there may be M receive channels in the receive array of the photoreceiver, and that each of the M receive channels receives N training reflection beams of N training laser beams, respectively. In an embodiment of the present application, 1 training laser beam may be emitted and each of the M receiving channels may be used to receive the reflected beam of the training laser beam and record the received signal strength (Power) respectively. Then, another training laser beam is emitted, and each of the M receiving channels is used for receiving the reflected beam of the another training laser beam and recording the received signal intensity. By repeating the above process for each training laser beam, a plurality of training reflected beams of the plurality of training laser beams reflected by the preset target object can be received by a plurality of receiving channels of the light receiver 106, respectively.

In another embodiment of the present application, N training laser beams may be emitted separately and N reflected beams of the N training laser beams are received separately with one of the M receiving channels and the received signal strengths are recorded. Thereafter, N training laser beams are respectively emitted, and N reflected beams of the N training laser beams are respectively received using another receiving channel and the received signal intensities are recorded. By repeating the above process for each receiving channel, a plurality of training reflected beams of a plurality of training laser beams reflected by a preset target object can be received by a plurality of receiving channels of the light receiver 106, respectively.

Through the above steps, the relationship between the signal intensities of the respective reception channels, the laser beams of the respective emission angles, and the reflected beams of the laser beams can be obtained. For example, the relationship may be represented by the following table 1.

TABLE 1 relation between signal intensities of receiving channel, laser beam and reflected beam

Thereafter, at block 706, signal strengths of each of the plurality of training reflected beams respectively received by each of the plurality of receive channels are compared.

The signal intensities may be compared by traversing the signal intensities of the reflected beams received by, for example, the respective receive channels for a training laser beam (one row in table 1) to find the receive channel with the greatest signal intensity, i.e., the best receive channel for that point. The receive channel is a receive channel corresponding to a training receive angle of the training laser beam.

The signal intensities may also be compared by traversing the signal intensities of the reflected beams, e.g., of the respective laser beams, for a receiving channel (a column in table 1), to find the reflected beam having the greatest signal intensity, i.e., the best receiving channel for the reflected beam.

Thereafter, at block 708, depending on the manner in which the signal strengths are compared, the training reception angle of the training reflection beam having the greatest signal strength among the training reflection beams received by each of the reception channels may be taken as the training reception angle corresponding to the reception channel, or the reception channel having the greatest signal strength among the reception channels receiving each of the training reception angles may be taken as the reception channel corresponding to the training reception angle.

By repeating the above operation for each training ranging laser beam and each receiving channel having different training emission angles, a plurality of training receiving angles and optimal receiving channels respectively corresponding to each training receiving angle are determined. For example, the relationship may be represented by the following table 2.

TABLE 3 relation table of receiving angles and receiving channels

The correspondence between the plurality of reception angles of the optical receiver and the plurality of reception channels of the optical receiver shown in table 2 is in the form of one-to-one correspondence of each reception angle and the corresponding reception channel. As discussed above, the correspondence between the plurality of reception angles and the plurality of reception channels of the optical receiver may be in the form of a one-to-one correspondence of each reception channel and the corresponding strongest reception angle range, for example, as shown in table 3 below.

TABLE 3 relation table of receiving angles and receiving channels

In addition, in the above training for the non-coaxial lidar system, since the target object is at a fixed distance, the emission angle and the reflection angle of the laser beam are also in one-to-one correspondence. Therefore, through the above training process, in addition to the correspondence between the reception angle of the reflected beam of the laser beam and the reception channel, the correspondence between the emission angle of the laser beam and the reception channel under the training condition can be obtained. For example, the relationship may be represented by the following table 4.

TABLE 4 Table of the relation between the emission angles and the reception channels under training conditions

It will be appreciated by those skilled in the art that the above relationship of the emission angle to the receiving channel is obtained for a target object at a known fixed distance under training conditions, and that the above relationship changes as the distance of the target object changes.

Similarly, the relationship between the transmission angle and the reception channel under the training condition may be a one-to-one correspondence between a range of transmission angles and the reception channel, in addition to the one-to-one correspondence between transmission angles and reception channels shown above, and a detailed description thereof will be omitted.

In embodiments of the present application, the size of the preset target object may be large enough to reflect the training ranging laser beam at each emission angle to the photodetector. Alternatively, the preset target object can be moved without changing the distance to the lidar system to reflect the training ranging laser beam at each emission angle to the photodetector, respectively.

In the above embodiments of the present disclosure, by training the non-coaxial lidar system in advance, the correspondence between the plurality of reception angles of the light receiver and the plurality of reception channels of the light receiver may be obtained. Thus, by using the correspondence, the optimal receiving channel can be selected according to the receiving angle of the reflected beam in the method shown in fig. 5 during the operation of the non-coaxial lidar system.

In addition, by training the non-coaxial lidar system in advance, the correspondence between the plurality of emission angles of the optical transmitter and the plurality of receiving channels of the optical receiver under the training condition can also be obtained.

Using the correspondence between the transmit angle and the receive channel, a first receive channel used in block 504 of fig. 5 may be determined. Based on the emission angle of the first ranging laser beam and according to the correspondence between the emission angle and the reception channel, the reception channel determined in the correspondence may be selected to receive the reflected beam.

The first reception channel may also be a default reception channel or a previously selected reception channel. Furthermore, the first receiving channel may be determined according to at least one of: application scenes of the non-coaxial laser radar system; the speed of movement of the non-coaxial lidar system; and the weather environment in which the non-coaxial lidar system is located.

For example, for a long-distance application scenario, for example, when the laser radar system 100 is installed in an autonomous car and the autonomous car is traveling fast on a public road, since the target object is mostly at a position farther away, a receiving channel having a smaller receiving angle may be selected as the initial receiving channel. In addition, for a short-range application scenario, for example, when the laser radar system 100 is installed in an automatic driving forklift and the automatic driving forklift is slowly traveling on an internal road, since a target object closer in distance is more concerned, a reception lane having a larger reception angle may be selected as an initial reception lane. In addition, for example, when the moving speed of the lidar system 100 is high, a reception channel having a small reception angle may be selected as the initial reception channel. When the moving speed of the lidar system 100 is slow, a reception channel having a larger reception angle may be selected as the initial reception channel. In addition, for example, when the lidar system 100 is in sunny weather, a reception channel having a smaller reception angle may be selected as the initial reception channel. When the lidar system 100 is in a rainy or foggy weather, a reception channel having a larger reception angle may be selected as the initial reception channel.

Returning to fig. 5, in an embodiment of the present disclosure, in block 504, it may also occur that the first receive channel does not receive the first reflected beam while the first reflected beam is received by the first receive channel. For example, when there is no target object in the direction of the first emission angle and thus the first ranging laser beam is not reflected, the first reflected beam is not generated and thus the first receiving channel does not receive the first reflected beam. Further, for example, when the selected first reception channel is not the optimal reception channel and the signal strength of the reflected beam received by the first reception channel is too low or the reflected beam is not received by the first reception channel, the first reflected beam cannot be received by the first reception channel.

In one embodiment of the present application, the target object may be considered to be absent and thus the first receive channel may be used to detect the reflected beam continuously without switching the receive channel.

In one embodiment of the present application, the first receiving channel may be considered not to be a suitable receiving channel, and thus another receiving channel other than the receiving channel corresponding to the current receiving channel among the plurality of receiving channels corresponding to the subsequent ranging laser beams, that is, the other receiving channel is selected for the subsequent ranging laser beams.

Accordingly, in the method 500 for configuring a lidar system according to embodiments of the present disclosure, a block 512 may also be included in which, in response to the first reflected beam not being received by the first receive channel, the first receive channel or another receive channel of the plurality of receive channels other than the first receive channel is selected as the second receive channel.

Fig. 8 shows a flowchart of a method 800 for configuring a lidar system according to an embodiment of the disclosure. The method 800 in fig. 8 provides an alternative embodiment of step 512 in fig. 5.

In one embodiment of the present application, in response to the first reflected beam not being received by the first receive channel, gain adjustment of a receive channel may also be considered before selecting another receive channel of the plurality of receive channels other than the first receive channel.

In this embodiment of the present application, the receive channel may provide a plurality of different gain levels for the received signal of the reflected laser beam. For example, a higher level of gain may amplify the received signal of the reflected laser beam more, while a lower level of gain may amplify the received signal of the reflected laser beam less. The gain levels provided by the receive channels may be two (high gain and low gain), three (high gain, medium gain and low gain) or more.

As shown in fig. 8, in response to the first reflected beam not being received by the first receive channel, a determination is first made in block 802 as to whether the gain level provided by the first receive channel can be increased.

Thereafter, the method proceeds to step 804 or 806 according to the determination result in step 802.

In the event that the gain level provided by the first receive channel can be increased, the method proceeds to step 804. In this step, the first receiving channel is selected as a second receiving channel for receiving a second reflected beam of the second ranging laser beam and increasing the gain level provided thereby.

That is, the receiving channel is not changed in this case, but the gain level of the receiving channel is increased. Thus, the received signal strength can be improved, which is beneficial to increasing the dynamic range of the receiving channel and reducing the number of times of changing the receiving channel as much as possible.

In the event that the gain level provided by the first receive channel cannot be increased, the method proceeds to step 806. In this step, another reception channel other than the first reception channel among the plurality of reception channels is selected as a second reception channel for receiving the second reflected beam of the second ranging laser beam and a gain level provided thereby is maintained, i.e., the other reception channel is selected for the subsequent ranging laser beam and the gain level of the reception channel is not changed.

That is, in this case, the other receiving channels are selected to receive the reflected laser light of the subsequent ranging laser beam.

In this embodiment, in addition to the advantages discussed with reference to the previous embodiments, by combining gain adjustment of the reception channels, it is possible to achieve reflected light detection of a large dynamic range and to minimize the number of switching times of the reception channels.

After step 512, the method 500 shown in FIG. 5 is repeated for subsequent ranging laser beams using the selected receive channel.

In an embodiment of the present application, the strategy of selecting other receiving channels includes: selecting receiving channels sequentially or at intervals according to the size sequence of the receiving angles; selecting a receiving channel from the first receiving channel according to the order of the receiving angles or at intervals; and randomly selecting a receive channel.

The strategy for selecting other receiving channels can be flexibly formulated by a person skilled in the art according to the requirement, so that the receiving channels capable of providing the detection result can be switched to as soon as possible.

By the above technical scheme, even if the first receiving channel cannot receive the reflected beam, the receiving channel which can provide the detection result can be quickly switched by continuously trying to select other receiving channels. Therefore, even if the light spot on the light receiver moves to another receiving unit due to the change in the distance of the target object, a suitable receiving channel can be found.

Fig. 9 shows a flowchart of a method 900 for configuring a lidar system according to another embodiment of the disclosure.

The method 900 begins at block 902 where a first ranging laser beam having a first emission angle is emitted by a light emitter of a non-coaxial lidar system. Thereafter, at block 904, a first reflected beam of the first ranging laser beam reflected by the target object is received by a first receive channel of an optical receiver. Thereafter, at block 906, a distance of the target object from the non-coaxial lidar system is calculated in response to receiving the first reflected beam by the first receive channel. Steps 902, 904, and 906 of method 900 are similar to steps 502, 504, and 506 of method 500 described above with reference to fig. 5, and thus are not described in detail.

Unlike method 500, however, at block 908 of method 900, a second angle of reception of a second reflected beam of a second ranging laser beam by the optical receiver is calculated from a second angle of emission of the second ranging laser beam and the distance by coordinate conversion between the first coordinate system and the second coordinate system.

In this embodiment, for a lidar system, the time interval between the first ranging laser beam and the second ranging laser beam is relatively small and the emission angles of the two may be the same or very close, so that the first ranging laser beam and the second ranging laser beam can strike the same target object and be reflected back. Thus, the target object may be considered to be closer to the lidar system than to the first ranging laser beam. Therefore, when the receiving channel of the second ranging laser beam is selected, the receiving angle of the reflected beam of the second ranging laser beam may be approximately determined using the distance measured based on the first ranging laser beam.

As will be apparent to one of skill in the art,

similar to what is described with reference to method 500, the second ranging laser beam may be a next ranging laser beam in the same emission field of view as the first ranging laser beam or a ranging laser beam of the same emission direction in a next emission field of view after the current emission field of view of the lidar. Those skilled in the art can use the above laser beam or other laser beam as a subsequent ranging laser beam according to the needs and the characteristics of the laser radar system used.

Thereafter, at block 910, a second receive channel for receiving a second reflected beam of a second ranging laser beam is selected from a plurality of receive channels of the optical receiver based on a second angle of receipt of the second reflected beam and a first correspondence between the plurality of angles of receipt of the optical receiver and the plurality of receive channels of the optical receiver, the first correspondence obtained by pre-training the non-coaxial lidar system.

In this embodiment, in response to receiving the first reflected beam by the first receive channel, a second receive angle is calculated, a closest receive angle to the calculated second receive angle of the plurality of receive angles may be determined, and a corresponding receive channel corresponding to the closest receive angle is selected as the second receive channel. For example, the nearest neighbor search method described with reference to method 500 may be used to find the angle closest to the calculated second angle of reception. After the angle is found, the corresponding receiving channel is selected as the final selected channel.

In another embodiment of the present disclosure, when the first correspondence between the plurality of reception angles of the optical receiver and the plurality of reception channels of the optical receiver includes the plurality of reception channels and the strongest reception angle range of each reception channel, in response to receiving the first reflected beam by the first reception channel, the second reception angle is calculated, and a reception channel having the strongest reception angle range including the calculated second reception angle among the plurality of reception channels may be selected as the second reception channel.

Further, similar to method 500, method 900 may further include a step of pre-training the non-coaxial lidar system as indicated by block 901, and may further include a step of selecting the first receive channel or another receive channel of the plurality of receive channels other than the first receive channel as the second receive channel in response to the first reflected beam not being received by the first receive channel as indicated by block 512.

Other matters described with reference to method 500 may also be incorporated into method 900 and are not repeated here.

In some embodiments, techniques for configuring a lidar system according to embodiments of the present disclosure may be implemented within one or more processors within the lidar system, e.g., by controller 108. In other embodiments, when the lidar system is installed in a vehicle device, the techniques of configuring the lidar system according to embodiments of the present disclosure may also be implemented in one or more processors of the vehicle device, such as by a vehicle controller. Alternatively, techniques for configuring a lidar system according to embodiments of the present disclosure may be implemented in conjunction with a vehicle controller and a controller of the lidar system.

Fig. 10 shows a schematic composition of a vehicle 1000 incorporating a lidar system according to an embodiment of the disclosure. Vehicle 1000 may be used to perform methods of configuring a lidar system, such as methods 500, 700, 800, and 900, according to embodiments of the present disclosure. Vehicle 1000 may include at least a lidar system 1002, a vehicle controller 1004, and a motorized system 1006. Lidar system 1002 may be implemented using lidar system 100 in fig. 1. Accordingly, the light source 1012, scanner 1014, light receiver 1016, and controller 1018 correspond to the light source 102, scanner 104, light receiver 106, and controller 108, respectively, of the lidar system 100. Except that the vehicle controller 1004 may be communicatively coupled to the light source 1012, the scanner 1014, and the light receiver 1016 by a controller 1018. In other embodiments, the vehicle controller 1004 may also be communicatively coupled directly to the light source 1012, the scanner 1014, and the light receiver 1016. In some embodiments, lidar system 1002 may not include controller 1018. The technique of configuring a lidar system according to embodiments of the present disclosure may be implemented independently by the vehicle controller 1004, or may be implemented in concert in part by the vehicle controller 1004 and in part by the controller 1018. The motorized system 1006 may include a power subsystem, a braking subsystem, a steering subsystem, and the like. Vehicle controller 1004 may adjust maneuver system 1006 based on the detection results of lidar system 1002.

Furthermore, techniques for configuring a lidar system according to embodiments of the present disclosure may also be implemented in an electronic device in the form of computer-readable instructions.

Fig. 11 shows a block diagram of a configuration of an electronic device 1100 according to an embodiment of the disclosure. Electronic device 1100 may be used to perform methods of configuring a lidar system, such as methods 500, 700, 800, and 900, according to embodiments of the present disclosure. The electronic device 1100 may be any type of general-purpose or special-purpose computing device, such as a desktop computer, laptop computer, server, mainframe computer, cloud-based computer, tablet computer, wearable device, vehicle electronics, or the like. As shown in fig. 11, the electronic device 1100 includes an Input/Output (I/O) interface 1101, a network interface 1102, a memory 1104, and a processor 1103.

The I/O interface 1101 is a collection of components that can receive input from a user and/or provide output to a user. The I/O interface 1101 may include, but is not limited to, buttons, a keyboard, a keypad, an LCD display, an LED display, or other similar display devices, including display devices having touch screen capabilities to enable interaction between a user and an electronic device.

The communication interface 1102 may include various adapters and circuitry implemented in software and/or hardware to enable communication with a lidar system using a wired or wireless protocol. The wired protocol is, for example, any one or more of a serial port protocol, a parallel port protocol, an ethernet protocol, a USB protocol, or other wired communication protocol. The wireless protocol is, for example, any IEEE 802.11Wi-Fi protocol, cellular network communication protocol, or the like.

Memory 1104 includes a single memory or one or more memories or storage locations including, but not limited to, random Access Memory (RAM), dynamic Random Access Memory (DRAM), static Random Access Memory (SRAM), read Only Memory (ROM), EPROM, EEPROM, flash memory, logic blocks of an FPGA, a hard disk, or any other layer of a memory hierarchy. The memory 1104 may be used to store any type of instructions, software, or algorithms, including instructions 1105 for controlling the general functions and operations of the electronic device 1100.

The processor 1103 controls the general operation of the electronic device 1100. The processor 1103 may include, but is not limited to, a CPU, a hardware microprocessor, a hardware processor, a multi-core processor, a single-core processor, a microcontroller, an Application Specific Integrated Circuit (ASIC), a DSP, or other similar processing device capable of executing any type of instructions, algorithms, or software for controlling the operation and functions of the electronic device 1100 in accordance with embodiments described in this disclosure. The processor 1103 may be various implementations of digital circuitry, analog circuitry, or mixed signal (a combination of analog and digital) circuitry that performs functions in a computing system. The processor 1103 may include, for example, a portion or circuit such as an Integrated Circuit (IC), an individual processor core, an entire processor core, an individual processor, a programmable hardware device such as a Field Programmable Gate Array (FPGA), and/or a system comprising multiple processors.

Internal bus 1106 may be used to establish communications between components of electronic device 1100.

The electronic device 1100 is communicatively coupled to a lidar system to be configured to control operation of the lidar system. For example, a configuration method according to the present disclosure may be stored on the memory 1104 of the electronic device 1100 in the form of computer readable instructions. The processor 1103 implements the configuration method by reading the stored computer readable instructions.

Although specific components are used to describe electronic device 1100, in alternative embodiments, different components may be present in electronic device 1100. For example, the electronic device 1100 may include one or more additional processors, memory, network interfaces, and/or I/O interfaces. In addition, one or more of the components may not be present in the electronic device 1100. Additionally, although separate components are shown in fig. 11, in some embodiments, some or all of a given component may be integrated into one or more of the other components in electronic device 1100.

The present disclosure may be implemented as any combination of apparatuses, systems, integrated circuits, and computer programs or program products on a non-transitory computer readable medium.

It should be understood that computer-executable instructions in a computer-readable storage medium or program product according to embodiments of the present disclosure may be configured to perform operations corresponding to the above-described apparatus and method embodiments. Embodiments of a computer readable storage medium or program product will be apparent to those skilled in the art when referring to the above-described apparatus and method embodiments, and thus the description will not be repeated. Computer readable storage media and program products for carrying or comprising the above-described computer-executable instructions are also within the scope of the present disclosure. Such a storage medium may include, but is not limited to, floppy disks, optical disks, magneto-optical disks, memory cards, memory sticks, and the like.

In addition, it should be understood that the series of processes and devices described above may also be implemented in software and/or firmware. In the case of implementation by software and/or firmware, a corresponding program constituting the corresponding software is stored in a storage medium of the relevant device, and when the program is executed, various functions can be performed.

For example, a plurality of functions included in one unit in the above embodiments may be implemented by separate devices. Alternatively, the functions realized by the plurality of units in the above embodiments may be realized by separate devices, respectively. In addition, one of the above functions may be implemented by a plurality of units. Such configurations are included within the technical scope of the present disclosure.

In the present disclosure, the steps described in the flowcharts include not only processes performed in time series in the order described, but also processes performed in parallel or individually, not necessarily in time series. Further, even in the steps of time-series processing, the order may be appropriately changed.

The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The term "or" in this disclosure means an inclusive "or" rather than an exclusive "or". References to a "first" component do not necessarily require the provision of a "second" component. Furthermore, unless explicitly indicated otherwise, reference to "a first" or "a second" component does not mean that the referenced component is limited to a particular order. The term "based on" means "based at least in part on.

Claims

1. A method for configuring a non-coaxial lidar system, comprising:

emitting, by a light emitter, a first ranging laser beam having a first emission angle, the light emitter having a first coordinate system associated therewith;

receiving a first reflected beam of the first ranging laser beam reflected by the target object by a first receiving channel of an optical receiver, the optical receiver having a second coordinate system associated therewith;

in response to receiving a first reflected beam by the first receive channel, calculating a distance of the target object from the non-coaxial lidar system;

calculating a first receiving angle at which the optical receiver receives the first reflected beam by coordinate conversion between the first coordinate system and the second coordinate system according to the first emitting angle and the distance; and

and selecting a second receiving channel for receiving a second reflected beam of a second ranging laser beam from a plurality of receiving channels of the optical receiver according to the first receiving angle and a first corresponding relation between the plurality of receiving angles of the optical receiver and the plurality of receiving channels of the optical receiver, wherein the first corresponding relation is obtained by training the non-coaxial laser radar system in advance.

2. The method of claim 1, wherein,

the first correspondence between the plurality of receiving angles of the optical receiver and the plurality of receiving channels of the optical receiver includes the plurality of receiving angles and the receiving channel corresponding to each of the plurality of receiving angles one by one, and

selecting a second receive channel from a plurality of receive channels of the optical receiver includes: in response to receiving a first reflected beam by the first receive channel, determining a closest receive angle of the plurality of receive angles to the calculated first receive angle, and selecting a corresponding receive channel corresponding to the closest receive angle as the second receive channel.

3. The method of claim 1, wherein,

the first correspondence between the plurality of receiving angles of the optical receiver and the plurality of receiving channels of the optical receiver includes a strongest receiving angle range of the plurality of receiving channels and each receiving channel, wherein, for reflected beams received at a receiving angle within the strongest receiving angle range, a signal strength detected by the receiving channel is greater than or equal to a signal strength detected by other receiving channels, and

selecting a second receive channel from a plurality of receive channels of the optical receiver includes: in response to receiving a first reflected beam by the first receive channel, a receive channel of the plurality of receive channels having a strongest range of receive angles including the first receive angle is selected.

4. A method for configuring a non-coaxial lidar system, comprising:

calculating a second receiving angle of a second reflected beam of the second ranging laser beam received by the light receiver through coordinate conversion between the first coordinate system and the second coordinate system according to a second emitting angle of the second ranging laser beam and the distance; and

and selecting a second receiving channel for receiving the second reflected beam from a plurality of receiving channels of the optical receiver according to the second receiving angle and a first corresponding relation between the plurality of receiving angles of the optical receiver and the plurality of receiving channels of the optical receiver, wherein the first corresponding relation is obtained by training the non-coaxial laser radar system in advance.

5. The method of claim 4, wherein,

selecting a second receive channel from a plurality of receive channels of the optical receiver includes: in response to receiving a first reflected beam by the first receive channel, determining a closest receive angle of the plurality of receive angles to the calculated second receive angle, and selecting a corresponding receive channel corresponding to the closest receive angle as the second receive channel.

6. The method of claim 4, wherein,

selecting a second receive channel from a plurality of receive channels of the optical receiver includes: in response to receiving a first reflected beam by the first receive channel, a receive channel of the plurality of receive channels having a strongest range of receive angles including the second receive angle is selected.

7. The method of claim 1 or 4, wherein the coordinate transformation between the first coordinate system and the second coordinate system comprises:

determining the polar coordinates of the target object in the first coordinate system according to the emission angle of the laser beam and the distance of the target object,

converting the polar coordinates of the target object in the first coordinate system into the polar coordinates of the target object in the second coordinate system according to the relative position relation between the first coordinate system and the second coordinate system, and

and determining the receiving angle of the reflected beam from the target object according to the polar coordinates of the target object in the second coordinate system.

8. The method of claim 7, wherein pre-training the non-coaxial lidar system comprises:

respectively emitting a plurality of training laser beams with different training emission angles by the light emitters;

receiving, by a plurality of receiving channels of the photoreceiver, a plurality of training reflected beams of the plurality of training laser beams reflected by a preset target object having a known distance, respectively, wherein the plurality of training laser beams have different training receiving angles, respectively, and each of the training receiving angles is calculated by coordinate conversion between the first coordinate system and the second coordinate system according to a corresponding training emitting angle and the known distance;

Comparing the signal strength of each of the plurality of training reflected beams received by each of the plurality of receive channels, respectively; and

the training receiving angle of the training reflected beam with the maximum signal intensity in the training reflected beam received by each receiving channel is taken as the training receiving angle corresponding to the receiving channel, or the receiving channel with the maximum signal intensity in the receiving channel receiving each training receiving angle is taken as the receiving channel corresponding to the training receiving angle.

9. The method according to claim 1 or 4, wherein,

the origin of the first coordinate system is located in the center of the emission aperture of the light emitter, and/or,

the origin of the second coordinate system is located at the center of the receiving aperture of the optical receiver.

10. The method according to claim 1 or 4, wherein,

the second ranging laser beam is a next ranging laser beam in the same emission field as the first ranging laser beam and/or a ranging laser beam at the same emission angle in a next emission field after the emission field of the first ranging laser beam.

11. The method of claim 1 or 4, wherein selecting a second receive channel from a plurality of receive channels of the optical receiver comprises:

The first receive channel is selected in response to the first reflected beam not being received by the first receive channel.

12. The method of claim 1 or 4, wherein selecting a second receive channel from a plurality of receive channels of the optical receiver comprises:

another one of the plurality of receive channels other than the first receive channel is selected in response to the first reflected beam not being received by the first receive channel.

13. The method of claim 1 or 4, wherein the plurality of receive channels provide a plurality of different gain levels to the received signal of the reflected laser beam, and

selecting a second receive channel from a plurality of receive channels of the optical receiver further comprises:

in response to the first reflected beam not being received by the first receive channel,

in case the gain level provided by the first receiving channel can be increased, selecting the first receiving channel and increasing the gain level provided by it, or

In the event that the gain level provided by the first receive channel cannot be increased, another one of the plurality of receive channels other than the first receive channel is selected and the gain level provided by it is maintained.

14. The method of claim 1 or 4, further comprising:

determining the first receiving channel according to the first emission angle and the second corresponding relation between a plurality of emission angles of the light emitter and a plurality of receiving channels of the light receiver,

the second corresponding relation is obtained by training the non-coaxial laser radar system in advance.

15. The method of claim 14, further comprising determining the first receive channel according to at least one of:

the application scene of the non-coaxial laser radar system;

the speed of movement of the non-coaxial lidar system; and

and the non-coaxial laser radar system is in a weather environment.

16. The method of claim 1 or 4, wherein the non-coaxial lidar system comprises a receiver array of a plurality of receiving sub-modules arranged along at least one direction, each of the plurality of receiving channels corresponding to a respective one of the receiving sub-modules in the receiver array.

17. A non-coaxial lidar system, comprising:

a light emitter configured to emit a plurality of ranging laser beams at different emission angles;

an optical receiver configured to detect a reflected beam, the reflected beam being the ranging laser beam reflected by a target object, the optical receiver having a plurality of receiving channels; and

A controller communicatively coupled with the optical transmitter and the optical receiver, the controller configured to perform the method of any of claims 1-16.

18. A vehicle, comprising:

a non-coaxial lidar system comprising an optical transmitter configured to transmit a plurality of ranging laser beams at different emission angles, and an optical receiver configured to detect a reflected beam, the reflected beam being the ranging laser beam reflected by a target object, the optical receiver having a plurality of receiving channels; and

a vehicle controller communicatively coupled with the non-coaxial lidar system, the vehicle controller configured to perform the method of any of claims 1-16.

19. An electronic device communicatively coupled with a non-coaxial lidar system, comprising:

a processor; and

a memory communicatively coupled to the processor and storing computer readable instructions that, when executed by the processor, cause the electronic device to perform the method of any of claims 1-16.

20. A computer readable storage medium storing computer readable instructions which, when executed by a processor of an electronic device communicatively coupled to a non-coaxial lidar system, cause the electronic device to perform the method of any of claims 1-16.

21. A computer program product comprising computer readable instructions which, when executed by a processor of an electronic device communicatively coupled to a non-coaxial lidar system, cause the electronic device to perform the method of any of claims 1-16.