Angle estimation method, device and equipment of laser radar and storage medium
By determining the mapping relationship between the echo energy value and the receiving channel, and calculating and calibrating the incident angle of the lidar, the problem of inaccurate ranging caused by the aging of lidar equipment was solved, ensuring the accuracy of ranging and point cloud data.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU ZVISION TECH CO LTD
- Filing Date
- 2022-10-31
- Publication Date
- 2026-05-29
Smart Images
Figure CN115792866B_ABST
Abstract
Description
Technical Field
[0001] This application relates to, but is not limited to, the field of lidar technology, and in particular to a lidar angle estimation method, apparatus, device, and storage medium. Background Technology
[0002] LiDAR (Light Detection and Ranging) is a target detection technology. It uses laser light as a signal source, emitting laser light towards a target object to collect the reflected signal, thereby obtaining information such as the target object's location and velocity. LiDAR has advantages such as high measurement accuracy and strong anti-interference capabilities, and is widely used in remote sensing, surveying, autonomous driving, robotics, and other fields.
[0003] In lidar systems that use detectors such as avalanche photodiodes (APDs) to receive echo beams, prolonged use of the equipment can lead to process aging, causing the point cloud data collected by the lidar to differ from the actual point cloud data during its service life, thus compromising the accuracy of distance measurement. Summary of the Invention
[0004] This application provides a method, apparatus, device, and storage medium for estimating the angle of a lidar, to ensure the accuracy of lidar ranging.
[0005] According to a first aspect of this application, a lidar angle estimation method is provided, the method comprising: obtaining M first echo energy values, where M is a positive integer; the M first echo energy values correspond one-to-one with M receiving channels, the M receiving channels being used to receive first echo beams; and determining the incident angle of the first echo beam corresponding to the first echo beam based on the mapping relationship between the M first echo energy values and the echo energy values corresponding to each receiving channel and the incident angle of the echo beam.
[0006] In one possible implementation, determining the incident angle of the first echo beam based on the mapping relationship between the first echo energy value and the incident angle of the echo beam includes: determining the first center coordinates of the echo spot of the first echo beam in the detector array based on the mapping relationship between the first echo energy value and the echo energy value corresponding to each receiving channel and the center coordinates of the echo spot in the detector array; and determining the incident angle of the first echo beam based on the first center coordinates.
[0007] In one possible implementation, the mapping relationship between the echo energy value corresponding to each receiving channel and the coordinates of the echo spot at the center of the detector array satisfies the following expression (1):
[0008] E i =f[(C ai C ei )-(Ltxa ,L txe (1)
[0009] Where i ranges from 1 to M integers, Ei is the first echo energy value received by the i-th receiving channel, (C ai C ei (L) represents the center coordinates of the regions corresponding to each receiving channel on the surface of the detector array. txa L txe ) represents the center coordinates of the echo spot on the detector array.
[0010] In one possible implementation, determining the incident angle of the first echo beam based on the first center coordinates includes: obtaining the first center coordinates, the size of the detector array, and the field of view angle of the lidar; and determining the incident angle of the first echo beam based on the mapping relationship between the center coordinates of the echo spot on the detector array and the incident angle of the echo beam, the first center coordinates, the size of the detector array, and the field of view angle of the lidar.
[0011] In one possible implementation, the mapping relationship between the center coordinates of the echo spot on the detector array and the incident angle of the echo beam satisfies the following expression (2):
[0012]
[0013] In the formula, Let φ be the azimuth angle of the incident angle of the echo beam, and φ be the elevation angle of the incident angle of the echo beam. The coordinates of the echo spot at the center of the detector array are (L... txa L txe ), L txa L is the x-coordinate value of the center coordinate. txe The vertical coordinate is the center coordinate, and the size of the detector array is L. a ×L e L a The length of the detector array in the azimuth direction, L e Let be the length of the detector array in the elevation direction, and let be the azimuth field of view angle of the lidar. The pitch field of view angle of the lidar is ±φ e .
[0014] In one possible implementation, before obtaining the first echo energy values of the first echo beams received by the M receiving channels, the method further includes: obtaining N second echo energy values, where N is an integer greater than or equal to M, the N first echo energy values correspond one-to-one with the N receiving channels, the N receiving channels are used to receive the second echo beams, and the emission angle of the second laser beam corresponding to the second echo beam is a preset value; and fitting a mapping relationship between the echo energy values corresponding to each receiving channel and the incident angle of the echo beam based on at least the second echo energy values and the incident angle of the second echo beam.
[0015] In one possible implementation, based on at least the second echo energy value and the emission angle of the second laser beam, fitting a mapping relationship between the echo energy value corresponding to each receiving channel and the emission angle of the laser beam includes: obtaining the incident angle of the second echo beam and the center coordinates of the regions corresponding to the N receiving channels on the detector array surface; determining the second center coordinates of the echo spot of the second echo beam on the detector array based on the incident angle of the second echo beam; and fitting a mapping relationship between the echo energy value received by each receiving channel and the incident angle of the echo beam based on the second center coordinates, the center coordinates of the regions corresponding to the N receiving channels on the detector array surface, and the second echo energy value.
[0016] According to a second aspect of this application, a compensation method for a lidar is provided, comprising: obtaining the incident angle of a first echo beam obtained by the method of the first aspect described above; determining the emission angle of the first laser beam based on the incident angle of the first echo beam and the mapping relationship between the incident angle of the echo beam and the emission angle of the laser beam, and performing an angle compensation method.
[0017] According to a third aspect of this application, an angle estimation device for a lidar is provided. This device can be a chip or system-on-a-chip in the lidar, or a functional module in the lidar for implementing the methods of the first aspect and any possible implementation thereof. The device can implement the functions performed by the lidar in the first aspect and any possible implementation thereof, and these functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned functions. The device includes: an acquisition module for acquiring M first echo energy values, where M is a positive integer, and the M first echo energy values correspond one-to-one with M receiving channels, the M receiving channels being used to receive first echo beams; and a determination module for determining the incident angle of the first echo beam based on the M first echo energy values and the mapping relationship between the echo energy values corresponding to each receiving channel and the incident angle of the echo beam.
[0018] In one possible implementation, the determining module is further configured to: determine the first center coordinates of the echo spot of the first echo beam in the detector array based on the mapping relationship between the first echo energy value and the echo energy value corresponding to each receiving channel and the center coordinates of the echo spot in the detector array; and determine the incident angle of the first echo beam according to the first center coordinates.
[0019] In one possible implementation, the mapping relationship between the echo energy value corresponding to each receiving channel and the center coordinates of the echo spot in the detector array satisfies expression (1).
[0020] In one possible implementation, the obtaining module is further configured to obtain the first center coordinates, the size of the detector array, and the field of view angle of the lidar; the determining module is further configured to: determine the incident angle of the first echo beam based on the mapping relationship between the center coordinates of the echo spot in the detector array and the incident angle of the echo beam, the first center coordinates, the size of the detector array, and the field of view angle of the lidar.
[0021] In one possible implementation, the mapping relationship between the center coordinates of the echo spot on the detector array and the incident angle of the echo beam satisfies expression (2).
[0022] In one possible implementation, the obtaining module is further configured to: obtain N second echo energy values, where N is an integer greater than or equal to M, the N first echo energy values correspond one-to-one with N receiving channels, the N receiving channels are used to receive the second echo beam, and the emission angle of the second laser beam corresponding to the second echo beam is a preset value; the device further includes: a fitting module, which is configured to fit the mapping relationship between the echo energy values received by each receiving channel and the incident angle of the echo beam based on at least the second echo energy values and the incident angle of the second echo beam.
[0023] In one possible implementation, the obtaining module is further configured to obtain the incident angle of the second echo beam and the center coordinates of the regions corresponding to the N receiving channels on the detector array surface; the determining module is further configured to determine the second center coordinates of the echo spot of the second echo beam on the detector array based on the incident angle of the second echo beam; and the fitting module is further configured to fit the mapping relationship between the echo energy value received by each receiving channel and the incident angle of the echo beam based on the second center coordinates, the center coordinates of the regions corresponding to the N receiving channels on the detector array surface, and the second echo energy value.
[0024] According to a fourth aspect of this application, a compensation device for a lidar is provided, the compensation device comprising: an acquisition module for acquiring the incident angle of a first echo beam obtained by the method described in the first aspect above; and a compensation module for determining the emission angle of the first laser beam based on the incident angle of the first echo beam and the mapping relationship between the incident angle of the echo beam and the emission angle of the laser beam, and performing angle compensation.
[0025] According to a fifth aspect of this application, a lidar is provided, comprising: a memory storing computer-executable instructions; and a processor connected to the memory for executing the computer-executable instructions to implement the method as described in the first and second aspects and any possible embodiments thereof.
[0026] According to a sixth aspect of this application, a computer storage medium is provided, the computer storage medium storing computer-executable instructions, characterized in that, after being executed by a processor, the computer-executable instructions are capable of implementing the methods described in the first aspect and the second aspect and any possible implementation thereof.
[0027] The advantages of the technical solution provided in this application compared with the prior art are as follows:
[0028] In this application, the incident angle of the first echo beam is determined based on the first echo energy value and the mapping relationship between the echo energy value received by each receiving channel and the incident angle of the echo beam. The incident angle can be calibrated, thereby ensuring the accuracy of lidar ranging.
[0029] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the scope of protection of this application. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the structure of a lidar in related technologies;
[0031] Figure 2 This is a schematic diagram of the first implementation process of the lidar angle estimation method in this application embodiment;
[0032] Figure 3 This is a schematic diagram of the second implementation process of the lidar angle estimation method in this application embodiment;
[0033] Figure 4 This is a schematic diagram of the third implementation process of the lidar angle estimation method in the embodiments of this application;
[0034] Figure 5 This is a schematic diagram of the channel array structure of the APD in the embodiments of this application;
[0035] Figure 6 This is a schematic diagram of the fourth implementation process of the lidar angle estimation method in the embodiments of this application;
[0036] Figure 7 This is a schematic diagram of the channel array of the echo beam incident on the APD in the embodiments of this application.
[0037] Figure 8 This is a schematic diagram of the angle estimation device for lidar in the embodiments of this application;
[0038] Figure 9 This is a schematic diagram of the structure of a lidar in an embodiment of this application. Detailed Implementation
[0039] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted to avoid unnecessary detail that could obscure the description of this application.
[0040] To illustrate the technical solution described in this application, specific embodiments are provided below.
[0041] LiDAR (Light Detection and Ranging) is a target detection technology. LiDAR emits a laser beam, which is diffusely reflected when it encounters a target object. A detector receives the reflected beam and, based on the emitted and reflected beams, determines the target object's distance, orientation, height, velocity, attitude, shape, and other characteristics.
[0042] The applications of lidar are very broad. Besides its military applications, it is now widely used in everyday life, including but not limited to: autonomous vehicles, autonomous aircraft, 3D printing, virtual reality, augmented reality, and service robots. Taking autonomous driving technology as an example, lidar installed in autonomous vehicles can scan the surrounding environment by rapidly and repeatedly emitting laser beams to obtain point cloud data reflecting the shape, position, and movement of one or more target objects in the environment.
[0043] It should be noted that the aforementioned intelligent driving technologies can refer to technologies such as driverless driving, autonomous driving, and driver assistance systems.
[0044] Figure 1 This is a schematic diagram of the structure of a lidar system in related technologies. For example... Figure 1As shown, the lidar 10 may include: a light emitting device 101, a light receiving device 102, and a processor 103. The light emitting device 101 and the light receiving device 102 are both connected to the processor 103.
[0045] The connections between the aforementioned devices can be electrical or optical fiber connections. More specifically, the optical transmitter 101 and the optical receiver 102 may each include multiple optical devices, and the connections between these optical devices may be spatial optical transmission connections.
[0046] The processor 103 is used to control the optical transmitter 101 and the optical receiver 102 so that the optical transmitter 101 and the optical receiver 102 can operate normally. For example, the processor 103 can provide driving voltages to the optical transmitter 101 and the optical receiver 102 respectively, and the processor 103 can also provide control signals to the optical transmitter 101 and the optical receiver 102.
[0047] For example, processor 103 can be a general-purpose processor, such as a central processing unit (CPU), a network processor (NP), etc.; processor 103 can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.
[0048] The light emitting device 101 also includes a light source ( Figure 1 (Not shown). It is understood that the aforementioned light source can refer to a laser, and the number of lasers can be one or more. Optionally, the laser can specifically include a pulsed laser diode (PLD), a semiconductor laser, a fiber laser, etc. The aforementioned light source is used to emit a laser beam. Specifically, the processor 103 can send an emission control signal to the light source, thereby triggering the light source to emit a laser beam.
[0049] Understandably, the aforementioned laser beam can also be referred to as a laser pulse, laser, or emission beam, etc.
[0050] The optical receiving device 102 typically uses photodiodes (such as avalanche photodiodes (APDs) or silicon photomultipliers (SiPMs)) as detectors to receive the echo beam and performs photoelectric conversion via a digital-to-analog converter (ACD). In practical applications, lidar usually employs detector arrays to improve echo reception efficiency and performance.
[0051] The lidar 10 may also include: one or more beam-shaping optical elements and a beam scanning device. Figure 1 (Not shown). On one hand, beam-shaping optics and a beam scanning device focus and project the laser beam toward a specific location in the surrounding environment (such as a target object). On the other hand, a beam scanning device and one or more beam-shaping optics guide and focus the returning beam onto the detector. A beam scanning device is used in the optical path between the beam-shaping optics and the target object. The beam scanning device effectively expands the field of view and increases the sampling density within the lidar's field of view.
[0052] The following is combined with Figure 1 The structure of the lidar shown is briefly described, along with the detection process of the lidar on the object 104 being measured.
[0053] See Figure 1 As shown, the laser beam propagates along the emission direction. When the laser beam encounters the object being measured 104, it is reflected from the surface of the object 104, and the reflected beam is received by the laser radar's optical receiving device 102. Here, the laser beam reflected back by the object 104 can be called the echo beam. Figure 1 The laser beam and echo beam are indicated by solid lines.
[0054] After receiving the echo beam, the optical receiver 102 performs photoelectric conversion on the echo beam, that is, converts the echo beam into an electrical signal. The optical receiver 102 outputs the electrical signal corresponding to the echo beam to the processor 103. The processor 103 can obtain point cloud data such as the shape, position, and motion of the object under test 104 based on the electrical signal of the echo beam.
[0055] In practical applications, as lidar is used for longer periods, it will experience equipment aging, which causes the laser beam emitted by the lidar to drift and change (i.e., the emission angle of the laser beam shifts). This results in the point cloud data collected by the lidar not matching the actual point cloud data, affecting the ranging accuracy of the lidar.
[0056] To address the aforementioned issues, this application provides an angle estimation method for lidar, which can be applied to the lidar described above.
[0057] It should be noted that the detector array in a lidar may include the channel array of an APD or the channel array of other photodetectors. This application embodiment uses the channel array of an APD as an example for specific explanation.
[0058] Figure 2 This is a schematic diagram of the first implementation process of the lidar angle estimation method in this application embodiment. See [link to relevant documentation]. Figure 2 The method may include:
[0059] S201, obtain M first echo energy values.
[0060] Where M is a positive integer, and the M first echo energy values correspond one-to-one with the M receiving channels. The M receiving channels are used to receive the first echo beam.
[0061] Understandably, when a lidar is measuring distance, it emits a laser beam A (the first laser beam). When this laser beam A encounters the object being measured, it is reflected from the surface of the object. The reflected echo beam A (the first echo beam) passes through the channel array of the APD. Assuming that M receiving channels on the APD's channel array all receive the echo beam A, then the echo energy value E of the echo beam A passing through these M receiving channels is collected. i (i.e., the energy value of the first echo E) i ).
[0062] It should be noted that when the lidar collects the energy value of the echo beam received from each receiving channel, it collects the energy value of only one receiving channel at a time until the energy value of the last receiving channel is collected. Therefore, the energy value of the receiving channels can be collected through an analog acquisition link, thereby reducing costs. The analog acquisition circuit may include an operational amplifier and an analog-to-digital converter, which are not specifically limited in this embodiment.
[0063] S202, Based on the mapping relationship between the M first echo energy values and the echo energy values corresponding to each receiving channel and the incident angle of the echo beam, determine the incident angle of the first echo beam.
[0064] Understandably, when the echo beam A passes through the channel array of the APD, it can pass through M receiving channels, and each of these M receiving channels receives a portion of the first echo energy value E of the echo beam A. i Where i takes the value of an integer from 1 to M. Then, the first echo energy value E of the echo beam A corresponding to each of the M receiving channels is... iThen, based on these M first echo energy values E i The mapping relationship between the echo energy value corresponding to each receiving channel and the incident angle of the echo beam A can be used to determine the incident angle of the echo beam A.
[0065] In one possible implementation, S202 may include: determining the first center coordinates of the echo spot of the first echo beam in the detector array based on the mapping relationship between the first echo energy value and the echo energy value corresponding to each receiving channel and the center coordinates of the echo spot in the detector array.
[0066] Understandably, when the echo beam A passes through the channel array of the APD, it will focus on the surface of the channel array to form an echo spot. The lidar will collect the first echo energy value E of the echo beam A received by the M receiving channels. i Then, based on the first echo energy value E i The mapping relationship between the echo energy value corresponding to each receiving channel and the center coordinates of the echo spot in the detector array can determine the coordinates of the optical center of the echo spot of echo beam A on the channel array of the APD (i.e., the first center coordinates).
[0067] Furthermore, the lidar can determine the coordinates of the optical center of the echo spot of the echo beam A on the channel array of the APD according to the following formula (1).
[0068] E i =f[(C ai C ei )-(L txa ,L txe (1)
[0069] In the formula, i takes the value of an integer from 1 to M, and E i Let C be the echo energy value received by the i-th receiving channel. ai C ei ) represents the center coordinates of the regions corresponding to each receiving channel on the surface of the detector array (i.e., the channel array of the APD), (L) txa L txe ) represents the center coordinates of the echo spot on the detector array. The mapping relationship function f can be obtained by the lidar at the factory by switching the receiving channels at different emission angles to obtain the energy of the actual channel, and then fitting the center position of the spot corresponding to the center of each channel and the center of the emission angle. Alternatively, it can be obtained by simulating various parameters of the lidar system.
[0070] For example, when the echo beam A passes through the channel array of the APD in the lidar, the lidar collects the first echo energy value E corresponding to the M receiving channels in the channel array of the APD for the echo beam A. i Based on the mapping relationship between the echo energy value on each receiving channel and the center coordinates of the echo spot on the detector array, the coordinates of the optical center of the echo beam A on the channel array surface of the APD are determined.
[0071] In one possible implementation, after the lidar determines the coordinates of the echo spot of the first echo beam at the first center of the detector array, S202 may further include: determining the incident angle of the first echo beam based on the first center coordinates.
[0072] Understandably, after the lidar determines the first center coordinates of the echo spot of the echo beam A on the channel array surface of the APD, it can determine the incident angle of the echo beam A corresponding to the first center coordinates based on the mapping relationship between the center coordinates of the echo spot on the detector array and the incident angle of the echo beam.
[0073] In one possible implementation, determining the incident angle of the first echo beam based on the first center coordinates includes: obtaining the first center coordinates, the size of the detector array, and the field of view angle of the lidar; and determining the incident angle of the first echo beam based on the mapping relationship between the center coordinates of the echo spot on the detector array and the incident angle of the echo beam, the first center coordinates, the size of the detector array, and the field of view angle of the lidar.
[0074] Understandably, there is a mapping relationship between the center coordinates of the echo spot and the incident angle of the echo beam. The parameters used in this mapping relationship are: the first center coordinates, the size of the detector array, the field of view angle of the lidar, and the incident angle of the echo beam. Among them, the mapping relationship, as well as the size of the detector array and the field of view angle of the lidar in the mapping relationship, are known. When the first center coordinates are known, the incident angle of the first echo beam can be calculated according to this mapping relationship. This mapping relationship can be expressed by expression (2):
[0075]
[0076] In the formula, Let φ be the azimuth angle of the incident angle of the echo beam, and φ be the elevation angle of the incident angle of the echo beam. The coordinates of the echo spot at the center of the detector array are (L... txa L txe ), L txa L is the x-coordinate value of the center coordinate. txe The vertical coordinate is the center coordinate, and the size of the detector array is L.a ×L e L a The length of the detector array in the azimuth direction, L e Let be the length of the detector array in the elevation direction, and let be the azimuth field of view angle of the lidar. The pitch field of view angle of the lidar is ±φ e .
[0077] It should be noted that, taking the channel array surface of the APD as the coordinate axis, and the azimuth zero degree and the horizontal incidence in the elevation direction as the reference zero degree, when the echo beam is incident horizontally in the elevation direction at the azimuth zero degree, the coordinates of the optical center of the echo beam on the channel array surface of the APD are the origin of the coordinates.
[0078] To implement the lidar angle estimation method, steps S201 to S202 may be included before the execution of steps S201 to S202. Specifically, Figure 3 This is a schematic diagram of the second implementation process of the lidar angle estimation method in this application embodiment. See [link / reference] Figure 3 As shown, S201 to S202 are executed before S301 to S302.
[0079] S301, obtain N second echo energy values.
[0080] Where N is an integer greater than or equal to M, the N first echo energy values correspond one-to-one with the N receiving channels, the N receiving channels are used to receive the second echo beam, and the emission angle of the second laser beam corresponding to the second echo beam is a preset value.
[0081] Understandably, before the lidar determines the emission angle of the laser beam A corresponding to the echo beam A based on the mapping relationship between the echo energy values received by each receiving channel and the emission angle of the laser beam, the above mapping relationship is first fitted. The first step in fitting the above mapping relationship is to assume that there are N receiving channels in the channel array of the lidar's APD that can receive the echo beam B (i.e., the second echo beam), where N is a positive integer less than or equal to the total number of receiving channels, and N is greater than or equal to M. Then, the echo energy value E' of the echo beam B corresponding to these N receiving channels is obtained. i (i.e., the energy value of the second echo).
[0082] S302, based on at least the second echo energy value and the incident angle of the second echo beam, fit the mapping relationship between the echo energy value received by each receiving channel and the incident angle of the echo beam.
[0083] Understandably, the lidar obtains the second echo energy value E' of the echo beam B. iThen, based on the second echo energy value E' of the echo beam B... i And the incident angle of the echo beam B, and fit the mapping relationship between the echo energy value corresponding to each receiving channel and the incident angle of the echo beam.
[0084] It should be noted that fitting the mapping relationship between the echo energy value corresponding to each receiving channel and the incident angle of the echo beam can be done before the lidar leaves the factory. This allows the lidar to directly estimate its angle during use after leaving the factory based on the above mapping relationship.
[0085] In one possible implementation, S302 may include S401 to S403 to implement the angle estimation method for lidar. Figure 4 This is a schematic diagram of the third implementation process of the lidar angle estimation method in this application. Figure 4 As shown, the method includes:
[0086] S401, obtain the incident angle of the second echo beam and the center coordinates of the regions corresponding to the N receiving channels on the detector array surface.
[0087] Understandably, in the process of fitting the mapping relationship between the echo energy value received by each receiving channel and the center coordinates of the echo spot in the detector array, the incident angle of the echo beam B and the center coordinates of the regions of the N receiving channels in the APD channel array that can receive the echo beam B are first obtained.
[0088] In one possible implementation, the center coordinates of the regions of the N receiving channels in the channel array of the APD that can receive the echo beam B can be determined based on the known relationship between the receiving channel and the FOV corresponding to the receiving channel.
[0089] In one embodiment, Figure 5 This is a schematic diagram of the channel array structure of the APD in the embodiments of this application. See also... Figure 5 As shown, the APD's channel array has four receiving channels, namely receiving channel C1, receiving channel C2, receiving channel C3, and receiving channel C4. The center coordinates of the region for receiving channel C1 are denoted as (C...). a1 C e1 The center coordinates of the receiving channel C2 area are (C a2 C e2 The center coordinates of the receiving channel C3 area are (C a3 C e3 The center coordinates of the receiving channel C4 area are (C a4 C e4All four receiving channels can receive the echo beam B, which is focused on the channel array surface of the APD to form an echo spot 501.
[0090] S402, based on the incident angle of the second echo beam, determine the second center coordinates of the echo spot of the second echo beam on the detector array.
[0091] Understandably, the lidar can determine the coordinates (i.e., the second center coordinates) of the optical center of the echo beam B on the channel array of the APD based on the incident angle of the echo beam B.
[0092] For example, suppose the size of the channel array of the APD is L a ×L e When designing the optical system for a lidar system, the lidar's field of view (FOV) is... Then, when the incident angle of the echo beam corresponding to the laser beam is At that time, the coordinates (expressed in angular coordinates) of the echo spot on the channel array surface of the APD are:
[0093] S403, based on the second center coordinates, the center coordinates of the regions corresponding to the N receiving channels on the detector array surface, and the second echo energy value, fit the mapping relationship between the echo energy value received by each receiving channel and the incident angle of the echo beam.
[0094] Understandably, the lidar can determine the coordinates of the optical center of the echo beam B on the channel array of the APD, the coordinates of the center of the region corresponding to the N receiving channels, and the second echo energy value E'. i The mapping relationship between the echo energy value received by each receiving channel and the incident angle of the echo beam is fitted.
[0095] Furthermore, the above mapping relationship fitted by the lidar can be expressed by the following formula (3).
[0096] E' i =f[(C ai C ei )-(L' txa ,L' txe (3)
[0097] In the formula, i takes the value of an integer from 1 to N, and E' i Let C be the second echo energy value received by the i-th receiving channel. ai C ei ) represents the center coordinates of the regions corresponding to each receiving channel on the surface of the detector array (i.e., the channel array of the APD), (L' txa ,L'txe (L') represents the center coordinates of the echo spot on the detector array, where (L') txa ,L' txe () is obtained from S402
[0098] It should be noted that the expressions of formula (3) and formula (1) are the same, only the acquisition time of the parameters is different. Formula (3) is the mapping relationship between the echo energy value of each receiving channel and the coordinates of the optical center of the echo spot on the detector array surface before the lidar leaves the factory. Formula (1) is used for angle estimation during the life cycle of the lidar.
[0099] The angle estimation method of the above-mentioned lidar is described below with specific embodiments.
[0100] Assume that the APD's channel array has 4 receiving channels that can receive the echo beam.
[0101] Figure 7 This is a schematic diagram of the channel array structure of the echo beam incident on the APD in the embodiments of this application. See also Figure 7 As shown, (a) indicates that echo beam A is focused on the channel array of the APD, and (b) indicates that echo beam B is focused on the channel array of the APD. Echo beam A is the echo beam received by the lidar during measurement, and echo beam B is the echo beam of a laser beam emitted at a preset angle. Here, the echo spots 701 and 702, focused on the channel array of the APD by echo beams A and B, are significantly different in position on the APD's channel array. Therefore, it is necessary to determine the appropriate method based on the specific conditions of the laser beam. Figure 6 Angle compensation is performed using this method. Figure 6 This is a schematic diagram of the fourth implementation process of the lidar angle estimation method in this application. See [link / reference] Figure 6 As shown, the method may include:
[0102] S601, the lidar obtains the echo energy values E'1, E'2, E'3, and E'4 of the echo beam B received by the four receiving channels capable of receiving the echo beam B, respectively, and the center coordinates (C) of the area corresponding to the four receiving channels. a1 C e1 ), (C a2 C e2 ), (C a3 C e3 ), (C a4 C e4 ) and the incident angle of the echo beam B.
[0103] S602, the lidar determines the coordinates (L') of the optical center of the echo spot 702 of the echo beam B on the channel array surface of the APD based on the incident angle of the echo beam B. txa ,L' txe ).
[0104] S603, the lidar uses the echo energy values E'1, E'2, E'3, E'4, and the coordinates of the area center corresponding to the four receiving channels (C) to determine the area center coordinates. a1 C e1 ), (C a2 C e2 ), (C a3 C e3 ), (C a4 C e4 The coordinates (L') of the optical center of echo spot 702 of echo beam B on the channel array surface of the APD. txa ,L' txe The first mapping relationship between the echo energy value received by the receiving channel and the incident angle of the echo beam is fitted.
[0105] S604, after executing S603, when the lidar performs ranging, it obtains the echo energy values E1, E2, E3, and E4 of the echo beam A received by the four receiving channels that can receive the echo beam A, as well as the coordinates of the center of the area corresponding to the four receiving channels (C). a1 C e1 ), (C a2 C e2 ), (C a3 C e3 ), (C a4 C e4 ).
[0106] S605, the lidar, based on the first mapping relationship obtained in S603, uses the echo energy values E1, E2, E3, E4 and the coordinates of the area center (C) corresponding to the four receiving channels. a1 C e1 ), (C a2 C e2 ), (C a3 C e3 ), (C a4 C e4 Determine the coordinates (L) of the optical center of echo spot 701 of echo beam A on the channel array surface of the APD. txa L txe ).
[0107] S606, the lidar uses the coordinates (L) of the optical center of the echo spot 701 of the echo beam A on the channel array surface of the APD. txa Ltxe ), determine the incident angle of the echo beam A.
[0108] This completes the angle estimation process for the lidar.
[0109] Therefore, in this embodiment of the application, the incident angle of the first echo beam is determined based on the mapping relationship between the first echo energy value and the echo energy value received by each receiving channel and the incident angle of the echo beam. The incident angle can be calibrated, thereby ensuring the accuracy of lidar ranging.
[0110] Based on the same inventive concept, this application also provides a compensation method for a lidar, which is implemented after executing the above-described lidar angle estimation method, including: obtaining the incident angle of a first echo beam; determining the emission angle of the first laser beam according to the mapping relationship between the incident angle of the first echo beam and the emission angle of the laser beam, and performing angle compensation.
[0111] Understandably, after determining the emission angle of laser beam A, the lidar can perform angle compensation on the emission angle of laser beam A based on that emission angle.
[0112] In one possible implementation, the mapping relationship between the incident angle of the first echo beam and the incident angle of the echo beam and the emission angle of the laser beam satisfies the following expression (4):
[0113]
[0114] In the formula, α' is the x-axis angle of the incident angle of the echo beam, β' is the y-axis angle of the incident angle of the echo beam, γ' is the z-axis angle of the incident angle of the echo beam, α is the x-axis angle of the emission angle of the laser beam, β is the y-axis angle of the emission angle of the laser beam, and γ is the z-axis angle of the emission angle of the first laser beam.
[0115] It should be noted that angle compensation based on the launch angle can solve the problem of not being able to guarantee the accuracy of the ranging results.
[0116] Based on the same inventive concept, this application also provides an angle estimation device for a lidar. This device can be a chip or system-on-a-chip in the lidar, or a functional module in the lidar used in the methods described in one or more of the above embodiments. This device can implement the functions performed by the lidar described in one or more of the above embodiments, and these functions can be implemented by hardware executing corresponding software. This hardware or software includes one or more modules corresponding to the above functions. Figure 8 This is a schematic diagram of the angle estimation device for lidar in an embodiment of this application. See also... Figure 8 As shown, the device 800 may include: an acquisition module 801, which can be used to acquire M first echo energy values, where M is a positive integer, and the M first echo energy values correspond one-to-one with M receiving channels, and the M receiving channels are used to receive the first echo beam; and a determination module 802, which can be used to determine the incident angle of the first echo beam based on the mapping relationship between the M first echo energy values and the echo energy values corresponding to each receiving channel and the incident angle of the echo beam.
[0117] In one possible implementation, the determining module 802 can also be used to: determine the first center coordinates of the echo spot of the first echo beam in the detector array based on the mapping relationship between the first echo energy value and the echo energy value corresponding to each receiving channel and the center coordinates of the echo spot in the detector array; and determine the incident angle of the first echo beam according to the first center coordinates.
[0118] In one possible implementation, the mapping relationship between the echo energy value received by each receiving channel and the coordinates of the echo spot at the center of the detector array satisfies expression (1).
[0119] In one possible implementation, the obtaining module 801 can also be used to: obtain the first center coordinates, the size of the detector array, and the field of view angle of the lidar; the determining module 802 can also be used to: determine the incident angle of the first echo beam based on the mapping relationship between the center coordinates of the echo spot in the detector array and the incident angle of the echo beam, the first center coordinates, the size of the detector array, and the field of view angle of the lidar.
[0120] In one possible implementation, the mapping relationship between the center coordinates of the echo spot on the detector array and the incident angle of the echo beam satisfies expression (2).
[0121] In one possible implementation, the obtaining module 801 can also be used to: obtain N second echo energy values, where N is an integer greater than or equal to M, the N first echo energy values correspond one-to-one with N receiving channels, the N receiving channels are used to receive the second echo beam, and the emission angle of the second laser beam corresponding to the second echo beam is a preset value; the device 800 further includes: a fitting module, which can be used to fit the mapping relationship between the echo energy values received by each receiving channel and the incident angle of the echo beam based on at least the second echo energy values and the incident angle of the second echo beam.
[0122] In one possible implementation, the obtaining module 801 can also be used to: obtain the incident angle of the second echo beam and the center coordinates of the regions corresponding to the N receiving channels on the detector array surface; the determining module 802 can also be used to: determine the second center coordinates of the echo spot of the second echo beam on the detector array based on the incident angle of the second echo beam; the fitting module can also be used to: fit the mapping relationship between the echo energy value received by each receiving channel and the incident angle of the echo beam based on the second center coordinates, the center coordinates of the regions corresponding to the N receiving channels, and the second echo energy value.
[0123] It should be noted that the specific implementation process of the above-mentioned acquisition module 801 and determination module 802 can be found in [reference needed]. Figures 2 to 7 For the sake of brevity, the detailed description of the embodiments will not be repeated here.
[0124] The obtaining module 801 and determining module 802 mentioned in the embodiments of this application can be one or more processors.
[0125] Based on the same inventive concept, embodiments of this application provide a compensation device for a lidar, the compensation device may include: an acquisition module, used to acquire the incident angle of a first echo beam obtained by the method described in the first aspect; and a compensation module, used to determine the emission angle of the first laser beam according to the incident angle of the first echo beam and the mapping relationship between the incident angle of the echo beam and the emission angle of the laser beam, and to perform angle compensation.
[0126] Based on the same inventive concept, this application provides a lidar, which can be the lidar described in one or more of the above embodiments. Figure 9 This is a schematic diagram of the structure of a lidar according to an embodiment of this application. See also... Figure 9 As shown, the lidar 900 can use general-purpose computer hardware, including a processor 901 and a memory 902.
[0127] Optionally, the processor 901 and the memory 902 can communicate via bus 903.
[0128] In one possible implementation, at least one processor 901 can constitute any physical device having circuitry that performs logical operations on one or more inputs. For example, at least one processor may include one or more integrated circuits (ICs), including application-specific integrated circuits (ASICs), microchips, microcontrollers, microprocessors, all or part of a central processing unit (CPU), graphics processing unit (GPU), digital signal processor (DSP), field-programmable gate array (FPGA), or other circuitry suitable for executing instructions or performing logical operations. Instructions executed by at least one processor may, for example, be preloaded into memory integrated with or embedded in the controller, or may be stored in separate memory. Memory may include random access memory (RAM), read-only memory (ROM), hard disk, optical disk, magnetic media, flash memory, other permanent, fixed, or volatile memory, or any other mechanism capable of storing instructions. In some embodiments, at least one processor may include more than one processor. Each processor may have a similar architecture, or processors may have different configurations that are electrically connected or disconnected from each other. For example, the processor may be a discrete circuit or integrated into a single circuit. When more than one processor is used, the processors may be configured to operate independently or collaboratively. Processors may be coupled electrically, magnetically, optically, acoustically, mechanically, or by other means that allow them to interact. According to one embodiment of this application, a computer-readable storage medium is also provided, on which computer instructions are stored, which are executed by a processor using the steps of the calibration method described above. Memory 902 may include computer storage media in the form of volatile and / or non-volatile memory, such as read-only memory and / or random access memory. Memory 902 may store operating systems, application programs, other program modules, executable code, program data, user data, etc.
[0129] Furthermore, the aforementioned memory 902 stores information for implementing... Figure 8 The computer executes instructions to obtain the functions of module 801 and module 802. Figure 8 The functions / implementation processes of the acquisition module 801 and the determination module 802 can be achieved through... Figure 9The processor 901 in the memory calls the computer execution instructions stored in the memory 902 to implement the function. For the specific implementation process and function, please refer to the above-mentioned related embodiments.
[0130] Based on the same inventive concept, this application provides a lidar, including: a memory storing computer-executable instructions; and a processor connected to the memory, used to execute the computer-executable instructions and to implement the lidar compensation method as described in one or more of the above embodiments.
[0131] Based on the same inventive concept, this application provides a computer storage medium that stores computer-executable instructions. After being executed by a processor, the computer-executable instructions can realize the compensation method of the lidar as described in one or more of the above embodiments.
[0132] Those skilled in the art will understand that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.
[0133] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.
Claims
1. A method for estimating the angle of a lidar, characterized in that, include: M first echo energy values are obtained, where M is a positive integer. The M first echo energy values correspond one-to-one with the M receiving channels, and the M receiving channels are used to receive the first echo beam. The incident angle of the first echo beam is determined based on the mapping relationship between the M first echo energy values and the echo energy values corresponding to each receiving channel and the incident angle of the echo beam. The step of determining the incident angle of the first echo beam based on the mapping relationship between the M first echo energy values and the echo energy values corresponding to each receiving channel and the incident angle of the echo beam includes: determining the first center coordinates of the echo spot of the first echo beam in the detector array based on the mapping relationship between the first echo energy values and the echo energy values corresponding to each receiving channel and the center coordinates of the echo spot in the detector array; and determining the incident angle of the first echo beam based on the first center coordinates. The step of determining the incident angle of the first echo beam based on the first center coordinates includes: obtaining the first center coordinates, the size of the detector array, and the field of view of the lidar; and determining the incident angle of the first echo beam based on the mapping relationship between the center coordinates of the echo spot in the detector array and the incident angle of the echo beam, the first center coordinates, the size of the detector array, and the field of view of the lidar. The mapping relationship between the center coordinates of the echo spot in the detector array and the incident angle of the echo beam satisfies the following expression: In the formula, The angle is the azimuth angle of the incident angle of the echo beam. Let be the elevation angle of the incident angle of the echo beam, and let the coordinates of the echo spot at the center of the detector array be ( L txa , L txe ), L txa The x-coordinate value of the center coordinate. L txe The vertical coordinate is the center coordinate, and the size of the detector array is L. a ×L e L a The length of the detector array in the azimuth direction, L e Let be the length of the detector array in the elevation direction, and let be the azimuth field of view angle of the lidar. The pitch field of view angle of the lidar is .
2. The method according to claim 1, characterized in that, The mapping relationship between the echo energy value corresponding to each receiving channel and the center coordinates of the echo spot in the detector array satisfies the following expression: Where i takes the value of an integer from 1 to M, E i Let be the energy value of the first echo received by the i-th receiving channel. C ai , C ei ) represents the center coordinates of the regions corresponding to each receiving channel on the surface of the detector array. L txa , L txe ) represents the center coordinates of the echo spot on the detector array.
3. The method according to claim 1, characterized in that, Before obtaining the M first echo energy values, the method further includes: N second echo energy values are obtained, where N is an integer greater than or equal to M. The N second echo energy values correspond one-to-one with N receiving channels. The N receiving channels are used to receive the second echo beam. The emission angle of the second laser beam corresponding to the second echo beam is a preset value. Based on at least the second echo energy value and the incident angle of the second echo beam, a mapping relationship between the echo energy value and the incident angle of the echo beam corresponding to each receiving channel is fitted.
4. The method according to claim 3, characterized in that, The step of fitting the mapping relationship between the echo energy value and the incident angle of the echo beam for each receiving channel based on at least the second echo energy value and the incident angle of the second echo beam includes: Obtain the incident angle of the second echo beam and the center coordinates of the regions corresponding to the N receiving channels on the detector array surface; Based on the incident angle of the second echo beam, determine the second center coordinates of the echo spot of the second echo beam on the detector array; Based on the second center coordinates, the center coordinates of the regions corresponding to the N receiving channels on the detector array surface, and the second echo energy value, a mapping relationship between the echo energy value received by each receiving channel and the incident angle of the echo beam is fitted.
5. A compensation method for a lidar system, characterized in that, include: Obtain the incident angle of the first echo beam obtained by the method as described in any one of claims 1 to 4; Based on the incident angle of the first echo beam and the mapping relationship between the incident angle of the echo beam and the emission angle of the laser beam, the emission angle of the first laser beam is determined and angle compensation is performed.
6. An angle estimation device for a lidar, characterized in that, The device includes: The acquisition module is used to acquire M first echo energy values, where M is a positive integer. The M first echo energy values correspond one-to-one with M receiving channels, and the M receiving channels are used to receive the first echo beam. The determining module is used to determine the incident angle of the first echo beam based on the mapping relationship between the M first echo energy values and the echo energy values corresponding to each receiving channel and the incident angle of the echo beam. The determining module is further configured to: determine the first center coordinates of the echo spot of the first echo beam in the detector array based on the mapping relationship between the first echo energy value and the echo energy value corresponding to each receiving channel and the center coordinates of the echo spot in the detector array; and determine the incident angle of the first echo beam according to the first center coordinates. The obtaining module is further configured to: obtain the first center coordinates, the size of the detector array, and the field of view angle of the lidar; The determining module is further configured to: determine the incident angle of the first echo beam based on the mapping relationship between the center coordinates of the echo spot in the detector array and the incident angle of the echo beam, the first center coordinates, the size of the detector array, and the field of view angle of the lidar. The mapping relationship between the center coordinates of the echo spot in the detector array and the incident angle of the echo beam satisfies the following expression: In the formula, The angle is the azimuth angle of the incident angle of the echo beam. Let be the elevation angle of the incident angle of the echo beam, and let the coordinates of the echo spot at the center of the detector array be ( L txa , L txe ), L txa The x-coordinate value of the center coordinate. L txe The vertical coordinate is the center coordinate, and the size of the detector array is L. a ×L e L a The length of the detector array in the azimuth direction, L e Let be the length of the detector array in the elevation direction, and let be the azimuth field of view angle of the lidar. The pitch field of view angle of the lidar is .
7. The apparatus according to claim 6, characterized in that, The mapping relationship between the echo energy value corresponding to each receiving channel and the center coordinates of the echo spot in the detector array satisfies the following expression: Where i takes the value of an integer from 1 to M, E i Let be the energy value of the first echo received by the i-th receiving channel. C ai , C ei ) represents the center coordinates of the regions corresponding to each receiving channel on the surface of the detector array. L txa , L txe ) represents the center coordinates of the echo spot on the detector array.
8. The apparatus according to claim 6, characterized in that, The obtaining module is further configured to: obtain N second echo energy values, where N is an integer greater than or equal to M, the N second echo energy values correspond one-to-one with N receiving channels, the N receiving channels are used to receive the second echo beam, and the emission angle of the second laser beam corresponding to the second echo beam is a preset value; The device further includes a fitting module, which is used to fit the mapping relationship between the echo energy value and the incident angle of the echo beam corresponding to each receiving channel based on at least the second echo energy value and the incident angle of the second echo beam.
9. The apparatus according to claim 8, characterized in that, The obtaining module is further configured to: obtain the incident angle of the second echo beam and the center coordinates of the regions corresponding to the N receiving channels on the detector array surface; The determining module is further configured to determine the second center coordinates of the echo spot of the second echo beam on the detector array based on the incident angle of the second echo beam. The fitting module is further configured to fit the mapping relationship between the echo energy value received by each receiving channel and the incident angle of the echo beam based on the second center coordinates, the center coordinates of the regions corresponding to the N receiving channels on the surface of the detector array, and the second echo energy value.
10. A compensation device for a lidar, characterized in that, include: The module is configured to obtain the incident angle of the first echo beam obtained by the method as described in any one of claims 1 to 4; The compensation module is used to determine the emission angle of the first laser beam and perform angle compensation based on the incident angle of the first echo beam and the mapping relationship between the incident angle of the echo beam and the emission angle of the laser beam.
11. A lidar, characterized in that, include: Memory, which stores computer-executable instructions; A processor, connected to the memory, is configured to implement the method as described in any one of claims 1 to 5 by executing the computer-executable instructions.
12. A computer storage medium storing computer-executable instructions, characterized in that, The computer-executable instructions, when executed by the processor, can implement the method as described in any one of claims 1 to 5.