Method for calibrating laser radar, distance measuring method, distance measuring circuit and radar

Abstract

The invention relates to a method for calibrating a laser radar, a distance measuring method, a distance measuring circuit and a radar, and the method for calibrating the laser radar comprises the steps: for each scanning block, receiving an optical signal from the scanning block through a line of pixels in at least one optical signal collection pixel array in a time period, the pixel corresponding to the light signal intensity peak value is determined, and the measurement distance and the echo area of the row of pixels are determined; repeating the following operations until the distance compensation value and the echo area corresponding to each reflection area are obtained: moving the movable flat plate, so that the plurality of reflection areas are respectively aligned with the laser radar in different time periods; wherein the distance compensation value is a difference value between the measurement distance and the preset distance; and switching the scanning blocks and repeating the operation until the distance compensation values and the echo areas corresponding to the scanning blocks under different reflectivity are obtained. The method can effectively improve the calibration precision of the laser radar, and improves the ranging precision of the laser radar.

Description

Technical Field

[0001] The present application relates to the field of computer technology, and in particular to a method for calibrating a laser radar, a ranging method, a ranging circuit and a radar. Background Art

[0002] With the rapid development of computer technology and information technology, autonomous driving technology has become more and more mature and has begun to provide users with convenient travel services. Radar can collect environmental information so that the autonomous driving decision-making system can adopt driving strategies that are compatible with the environmental information, such as obstacle avoidance.

[0003] However, the measurement results of the calibrated radar in the related art are of low accuracy and cannot meet the high-precision requirements of users. After research and analysis by the applicant, it was found that the low accuracy of the radar measurement results is at least partly due to the low radar calibration accuracy. For example, the related art considers fewer factors that affect the measurement accuracy when calibrating the laser radar, resulting in the calibration accuracy to be improved. Summary of the invention

[0004] In order to solve or partially solve the problems existing in the related art, the present application provides a method for calibrating a laser radar, a ranging method, a ranging circuit and a radar, which can improve the calibration accuracy of the laser radar and thereby improve the accuracy of the measurement results of the laser radar.

[0005] In a first aspect, the present application provides a method for calibrating a laser radar, wherein the laser radar includes at least one light signal acquisition pixel array and at least one laser array, each light signal acquisition array includes a plurality of pixels arranged in an array, and each laser array includes M×N scanning blocks. The method includes: for each scanning block, a row of pixels in at least one light signal acquisition pixel array receives a light signal from the scanning block within a time period to determine a pixel corresponding to a peak value of the light signal intensity, and determines a measured distance and an echo area of ​​the row of pixels; repeating the following operations until a distance compensation value and an echo area corresponding to each reflection area are obtained: moving a movable plate so that each of the plurality of reflection areas is aligned with the laser radar at different time periods; wherein the distance compensation value is the difference between the measured distance and the preset distance; switching the scanning blocks and repeating the above operations until distance compensation values ​​and echo areas corresponding to each scanning block at different reflectivities are obtained.

[0006] A second aspect of the present application provides a method for improving the ranging accuracy of a laser radar, wherein the laser radar includes at least one optical signal acquisition pixel array and at least one laser array, each optical signal acquisition array includes a plurality of pixels arranged in an array, and each laser array includes a plurality of scanning blocks. The method includes: in response to obtaining a scanning block number and an echo area, determining a storage address in a storage space, wherein the storage space stores a correspondence between the scanning block number, the echo area, and the distance compensation value; obtaining a distance compensation value from the storage space based on the storage address; and compensating the distance determined by the laser radar based on the distance compensation value.

[0007] According to a third aspect of the present application, there is provided a circuit for improving the ranging accuracy of a laser radar, wherein the laser radar comprises at least one optical signal acquisition pixel array and at least one laser array, each optical signal acquisition array comprising a plurality of pixels arranged in an array, and each laser array comprising a plurality of scanning blocks, and the circuit comprises: a storage address determination circuit for determining a storage address in a storage space in response to obtaining a scanning block number and an echo area, wherein the storage space stores a correspondence between the scanning block number, the echo area and the distance compensation value; a compensation value acquisition circuit for acquiring a distance compensation value from the storage space based on the storage address; and a distance compensation circuit for compensating for the distance determined by the laser radar based on the distance compensation value.

[0008] A fourth aspect of the present application provides a chip, comprising a circuit for improving the ranging accuracy of a laser radar as described above.

[0009] The fifth aspect of the present application provides a board card, including a circuit or chip as described above for improving the ranging accuracy of laser radar.

[0010] In a sixth aspect, the present application provides a radar, comprising at least one of the circuits, chips or boards described above for improving the ranging accuracy of laser radar.

[0011] A seventh aspect of the present application provides an electronic device, comprising: a processor; and a memory, on which executable code is stored, and when the executable code is executed by the processor, the processor executes the method as described above.

[0012] An eighth aspect of the present application provides a computer-readable storage medium having executable code stored thereon. When the executable code is executed by a processor of an electronic device, the processor executes the above method.

[0013] A ninth aspect of the present application provides a computer program product, comprising an executable code, which implements the above method when the executable code is executed.

[0014] The technical solution provided by the present application may include the following beneficial effects: by transmitting and receiving an object at a specific distance in units of scanning blocks and pixel lines, the measured distance and echo area can be obtained, so that the distance compensation value between the specific distance and the measured distance can be obtained, and then the corresponding relationship between the echo area and the distance compensation value, that is, the energy calibration result, can be obtained. In this way, after compensating the ranging result of the laser radar based on the calibration result, the influence of the energy difference on the ranging result is eliminated, and the accuracy of the ranging result is improved.

[0015] In certain embodiments of the present application, considering the limitation of calibration data and in order to reduce calibration costs, the fitting results of uncalibrated data can be obtained by interval linear calculation.

[0016] In some embodiments of the present application, the storage address can be calculated according to the scanning block number, the row address and the column address of the pixel, so as to conveniently obtain an accurate distance compensation value from the storage space.

[0017] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages of the present application will become more apparent by describing in more detail exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0019] Figure 1 It is a schematic diagram of an application scenario of a method for calibrating a laser radar, a ranging method, a ranging circuit, and a radar shown in an embodiment of the present application;

[0020] Figure 2 It is a schematic diagram of another application scenario of a method for calibrating a laser radar, a ranging method, a ranging circuit, and a radar shown in an embodiment of the present application;

[0021] Figure 3 is a schematic diagram of an accuracy calibration process shown in an embodiment of the present application;

[0022] Figure 4 It is a structural schematic diagram of a receiving sensor calibration platform shown in an embodiment of the present application;

[0023] Figure 5 is a schematic diagram of optical signal acquisition pixel array deviation shown in an embodiment of the present application;

[0024] Figure 6 is a block diagram of a method for calibrating a laser radar according to an embodiment of the present application;

[0025] Figure 7is a schematic diagram of a dynamic calibration platform shown in an embodiment of the present application;

[0026] Figure 8 is a data curve obtained by moving the calibration shown in an embodiment of the present application;

[0027] Fig. 9 is a flow chart of a method for improving laser radar ranging accuracy shown in an embodiment of the present application;

[0028] Fig.10 This is a data flow diagram for improving the ranging accuracy of a laser radar as shown in an embodiment of the present application;

[0029] Fig.11 is a schematic diagram of a data format shown in an embodiment of the present application;

[0030] Fig.12 It is a schematic diagram of the linear calculation compensation value of energy calibration distance shown in an embodiment of the present application;

[0031] Fig.13 is a data flow diagram for improving the ranging accuracy of a laser radar as shown in another embodiment of the present application;

[0032] Fig.14 is a schematic diagram of a data format shown in another embodiment of the present application;

[0033] Fig.15 is a schematic diagram of a temperature calibration process shown in an embodiment of the present application;

[0034] Fig.16 is a structural schematic diagram of a temperature calibration platform shown in an embodiment of the present application;

[0035] Fig.17 is a structural schematic diagram of a temperature calibration platform shown in another embodiment of the present application;

[0036] Fig.18 is a data flow diagram for improving the ranging accuracy of a laser radar as shown in another embodiment of the present application;

[0037] Fig.19 is a schematic diagram of a data format shown in another embodiment of the present application;

[0038] Fig. 20 is a schematic diagram of an absolute distance calibration process shown in an embodiment of the present application;

[0039] Fig.21 is a data flow diagram for improving the ranging accuracy of a laser radar as shown in another embodiment of the present application;

[0040] Fig. 22 is a schematic diagram of a data format shown in another embodiment of the present application;

[0041] Fig.23 is a schematic diagram of a distance compensation value calculation process shown in another embodiment of the present application;

[0042] Fig.24 is a schematic diagram of a pipeline structure for calculating distance shown in an embodiment of the present application;

[0043] Fig.25 is a reflectivity calibration flow chart shown in an embodiment of the present application;

[0044] Fig.26 is a data curve of echo area and distance under different reflectivity shown in an embodiment of the present application;

[0045] Fig. 27 is a structural schematic diagram of a reflectivity calibration platform shown in an embodiment of the present application;

[0046] Fig.28 is a data flow diagram for improving the ranging accuracy of a laser radar as shown in another embodiment of the present application;

[0047] Fig.29 is a schematic diagram of a reflectivity calibration lookup table shown in an embodiment of the present application;

[0048] Fig.30 is a schematic diagram of a process for solving an echo area corresponding to a standard reflectivity and a distance, shown in an embodiment of the present application;

[0049] Fig.31 is a schematic diagram of a process of solving reflectivity by interpolation, shown in an embodiment of the present application;

[0050] Fig.32 is a schematic diagram of a pipeline structure for calculating reflectivity shown in an embodiment of the present application;

[0051] Fig.33 is a schematic diagram of a process for solving an echo area corresponding to a standard reflectivity and a distance, shown in another embodiment of the present application;

[0052] Fig.34 is a schematic diagram of the data format of the reflectivity calibration coefficient shown in an embodiment of the present application;

[0053] Fig.35 A circuit for improving the ranging accuracy of a laser radar is shown in an embodiment of the present application;

[0054] Fig.36 A circuit for improving the accuracy of laser radar reflectivity measurement shown in an embodiment of the present application;

[0055] Fig.37 is a schematic diagram of the structure of a radar shown in an embodiment of the present application;

[0056] Fig.38It is a schematic diagram of the structure of an electronic device shown in an embodiment of the present application. DETAILED DESCRIPTION

[0057] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0058] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "an" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0059] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0060] In order to facilitate the understanding of the present application, some concepts involved in the present application are first explained.

[0061] LiDAR: By emitting outgoing light (such as a laser beam) with a wavelength of about 900nm, the outgoing light will be reflected by the obstacle after encountering it. The processing unit calculates the distance between the obstacle and the vehicle-mounted LiDAR based on the time difference between the reflected light and the outgoing light. In addition, the processing unit can also estimate the reflectivity of the target based on the echo area of ​​the reflected light signal obtained after receiving the reflected light. Vehicle-mounted LiDAR has a small size and a high degree of integration.

[0062] After completing the scanning control, the laser radar collects and calculates the measurement results. Due to the characteristics of the device itself and other reasons, there are deviations in the measurement results of each machine. Therefore, the measurement results need to be calibrated and corrected to achieve more accurate measurement performance.

[0063] The embodiment of the present application provides a method for calibrating a laser radar, a distance measurement method, a distance measurement circuit, and a radar, which transmits and receives an object at a specific distance in units of scanning blocks and pixel lines, and can obtain a measured distance and an echo area, so that a distance compensation value between the specific distance and the measured distance can be obtained, and then a corresponding relationship between the echo area and the distance compensation value can be obtained. In this way, the laser radar can determine the distance compensation value according to the corresponding relationship and the current echo area, which helps to improve the laser radar ranging accuracy.

[0064] In addition, some embodiments of the present application can also determine the corresponding relationship between temperature and distance compensation value, so that the laser radar can determine the distance compensation value according to the corresponding relationship and the current temperature, which helps to improve the ranging accuracy of the laser radar at different temperatures.

[0065] In addition, some embodiments of the present application can also determine the correspondence between the detection distance and the distance compensation value. In this way, the laser radar can determine the distance compensation value according to the correspondence and the current detection distance, which helps to improve the ranging accuracy of the laser radar when the target object is at different distances.

[0066] In addition, certain embodiments of the present application also provide a reflectivity determination method, which helps to improve the reflectivity measurement accuracy of the laser radar when the target object has different reflectivities.

[0067] The technical solution of the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0068] Figure 1 It is a schematic diagram of an application scenario of a method for calibrating a laser radar, a ranging method, a ranging circuit, and a radar shown in an embodiment of the present application.

[0069] Figure 1The hardware structure of the vehicle 10 supporting assisted driving or automatic driving functions is shown. For example, at least one laser radar (Light Detection and Ranging, referred to as LIDAR) 11 is mounted on the roof and / or the side of the vehicle body of the vehicle 10. The detection area of ​​the LIDAR 11 can be fixed, such as a certain LIDAR 11 can be used only for detection of a preset area. The detection area of ​​the LIDAR 11 can be adjustable, such as the laser radar on the vehicle body can scan multiple detection areas by adjusting the posture, etc., or by adjusting the field of view angle range of the laser radar itself. In addition, the vehicle 10 can also be equipped with multiple millimeter wave radars in a manner surrounding the vehicle 10. For example, the vehicle 10 is equipped with 4 millimeter wave radars, with the left side in front of the vehicle, the right side in front of the vehicle, the left side behind the vehicle, and the right side behind the vehicle as the detection range. Through the millimeter wave radar, the distance of the object existing in each detection area can be detected, and the relative speed of the object and the vehicle 10 can be detected.

[0070] Furthermore, the vehicle 10 may also be equipped with a positioning device 12 , such as a Beidou positioning device, a Global Positioning System (GPS), etc. The current position of the vehicle 10 can be determined by the positioning device 12 .

[0071] In addition, the vehicle 10 may also be equipped with an electronic control unit (ECU). The detection signal of at least one of the above-mentioned LIDAR 11, millimeter wave radar and positioning device 12 is sent to the ECU. The ECU can detect and identify obstacles (such as roadblocks, moving objects, trees, adjacent vehicles, etc. around the vehicle 10) based on these signals. In addition, the ECU can be physically divided into multiple units according to their functions, and this application will collectively refer to them as ECUs.

[0072] It should be noted that although the movable device is described as a car, such description is not restrictive and is applicable to a variety of movable devices, such as land robots, water robots, etc.

[0073] Figure 2 It is a schematic diagram of a method for calibrating a laser radar, a ranging method, a ranging circuit, and another application scenario of a radar shown in an embodiment of the present application.

[0074] Figure 2 The aircraft 20 shown may be an aircraft with an assisted driving function and an automatic driving function. The aircraft 20 may include a sensor system 21 and a power mechanism 22 .

[0075] The sensing system 21 may include one or more sensors to sense at least one of the surrounding obstacles, spatial orientation, speed or acceleration of the aircraft 20. The types of sensors include, but are not limited to, ranging sensors, position sensors, motion sensors, inertial sensors or image sensors. The sensing data provided by the sensing system 21 can be used to control the spatial orientation, speed and / or acceleration of the aircraft 20. The sensing system 21 is used to collect relevant information of the aircraft 20. Different types of sensors can sense different types of signals or sense signals from different sources. For example, the sensor includes a radar, an inertial sensor, a GPS sensor, or a visual / image sensor (such as a camera).

[0076] The method for calibrating a laser radar, the method, and the clock circuit of the embodiment of the present application can be applied to Figure 1 or Figure 2 Any one or more electronic devices such as the LIDAR 11, millimeter wave radar, positioning device 12, ECU, sensor system 21 or communication system shown need to use a clock.

[0077] In the above-mentioned application scenarios such as assisted driving, autonomous driving, and smart transportation, quickly and accurately perceiving the surrounding environment of movable equipment is a key point.

[0078] Here, the vehicle's autonomous driving scenario is used as an example for illustrative explanation. According to the vehicle position information, obstacle information, and road information perceived by the sensor system, road signal control is coordinated to improve the quality and efficiency of road management. Specifically, the corresponding autonomous driving vehicle decision can be determined based on the information perceived by the sensor system, and the safe distance between autonomous driving vehicles can be adjusted, so that the vehicle can drive safely and reliably on the road.

[0079] As one of the most important sensors for autonomous driving, LiDAR can provide the decision-making system with important information such as the location, size, and movement of traffic participants in the fields of smart transportation, assisted driving, and autonomous driving. LiDAR is like a person's eyes to autonomous vehicles. How to protect the security of LiDAR data collection and transmission is particularly important, as it is directly related to the personal safety, property safety, and even life safety of the drivers and passengers of the vehicle.

[0080] Related Technology In order to improve the accuracy of LiDAR detection results, the LiDAR can be calibrated before leaving the factory.

[0081] However, the applicant found that the accuracy of the calibrated LiDAR of the related art still cannot meet user needs. After a lot of research and analysis by the applicant, it was found that in the display use environment of the LiDAR, there are many influencing factors that will affect the accuracy of the calibration results of the LiDAR. For example, there are differences in the spatial position parameters and photoelectric parameters of the optical signal acquisition pixel arrays and laser arrays of multiple LiDARs, which will affect the calibration accuracy of the LiDAR. For example, when the temperature of the external environment is different, there will be differences in the calibration results, which will affect the calibration accuracy of the LiDAR. For example, if the reflectivity of the target object is different, it will also affect the accuracy of the ranging results.

[0082] Specifically, the laser emitting device (VCSEL array) contains multiple units (cells), and the parasitic parameters and resistance and capacitance (RC) constants of each cell are not consistent, which makes the turn-on time of light emission inconsistent. The row and column array routing of VCSEL is not completely equal, resulting in a certain delay deviation in the routing.

[0083] The optical signal acquisition pixel array is used as a receiving sensor (Sensor), and its front end is mainly composed of a photoelectric sensor array (such as a single photon avalanche device (SPAD), avalanche photodiode (APD), etc.), a gain circuit, and a time-to-digital converter (TDC) unit. Among them, the photoelectric sensor array and the gain circuit are analog circuits, and the parasitic parameters are different.

[0084] In addition, the echo area needs to be calibrated. For example, in the distance measurement solution, the echo characteristics will affect the accuracy of the algorithm. When the echo is saturated, the waveform is distorted, or when the amplitude is low, the effective signal-to-noise ratio is reduced, making it impossible for the distance measurement algorithm to calculate the most realistic timing moment.

[0085] In addition, the reflectivity needs to be calibrated. For example, when the transmitting circuit is fixed, according to the radar equation, the reflectivity is proportional to the echo energy and inversely proportional to the distance. Due to the different pixel positions, each transceiver and lens position will cause different reflectivity calculation coefficient deviations, requiring separate reflectivity calibration.

[0086] In addition, the optical angle needs to be calibrated: there is some deviation between the theoretical angle in the design and the actual processing and installation, which will affect the ranging results as the distance increases.

[0087] Based on the above reasons, the present application aims to provide a technical solution that can accurately and conveniently achieve functions such as high-precision calibration.

[0088] Figure 3 It is a schematic diagram of the accuracy calibration process shown in an embodiment of the present application.

[0089] See also Figure 3 In order to avoid the complex calibration under the different mapping relationships between the optical signal acquisition pixel array and the laser array, the differences caused by the transmitting device and the receiving device can be decoupled.

[0090] Specifically, first, the relevant parameters of the distance information output by the laser radar can be determined. Then, the relevant parameters can be decoupled to determine the calibration order for the corresponding relationship between some relevant parameters and the distance compensation value. Then, the corresponding relationship between some relevant parameters and the distance compensation value is calibrated according to the calibration order.

[0091] For example, the difference between the pixels of the receiving device is first calibrated (hereinafter referred to as receiving calibration), and then the difference between different scanning blocks and different echo areas (which represent energy) is calibrated (called energy calibration or dynamic calibration). Alternatively, the accuracy at different temperatures can be calibrated (called temperature calibration or static expression), and then the absolute distance calibration is performed. In addition, the reflectivity calculation can also be performed based on the calibrated detection distance.

[0092] In a specific embodiment, the laser radar includes at least one light signal collection pixel array and at least one laser array, each light signal collection array includes a plurality of pixels arranged in an array, and each laser array includes M×N scanning blocks.

[0093] Accordingly, calibrating the correspondence between some relevant parameters and distance compensation values ​​in accordance with the calibration sequence may include the following operations: sequentially performing reception calibration, energy calibration, temperature calibration and absolute distance calibration on the laser radar.

[0094] The following are illustrative examples of various calibration processes.

[0095] Figure 4 is a structural diagram of a receiving sensor calibration platform shown in an embodiment of the present application. Figure 4 In the receiving calibration process, the laser emission can use a line light source + a uniform light sheet to form a unified surface emission, and then measure the entire receiving surface to obtain the distance of at least some pixels, and finally calculate the difference of at least some pixels.

[0096] Figure 4 In the process, it is necessary to ensure a fixed distance d, for example, the distance is set to 2m, and keep the plane target parallel to the radar.

[0097] Specifically, the receiving calibration process may include the following operations: First, based on a standard light source, at least one optical signal acquisition pixel array is calibrated to obtain the attribute differences of the pixels of at least one optical signal acquisition pixel array. Then, the distance determined by the laser radar is compensated based on the attribute differences of the pixels. Receiving calibration can effectively improve problems such as parasitic parameters, inconsistent RC constants, and incompletely equal VCSEL row and column array routing, resulting in a certain delay deviation in the routing.

[0098] Figure 5 Schematic diagram of optical signal acquisition pixel array deviation shown in one embodiment of the present application.

[0099] See also Figure 5 The calculated pixel distance deviation data is as shown in the figure. The input is the row and column number of the pixel, and the output is the distance deviation value.

[0100] It should be noted that after all pixels are calculated, data analysis is performed to find some rules in the same row or column to simplify the whole machine calibration process.

[0101] The energy calibration process is described below by way of example: For example, the laser radar includes at least one light signal acquisition pixel array and at least one laser array, each light signal acquisition array includes a plurality of pixels arranged in an array, and each laser array includes M×N scanning blocks.

[0102] Figure 6 It is a block diagram of a method for calibrating a laser radar shown in an embodiment of the present application. Figure 7 It is a schematic diagram of a dynamic calibration platform shown in an embodiment of the present application.

[0103] Please also see Figure 6 and Figure 7 , the method for calibrating the laser radar includes operations S610 to S630. The calibration platform for energy calibration (dynamic form) of the laser radar includes: a movable plate at a preset distance from the laser radar, the movable plate includes a plurality of reflection areas, at least some of the reflection areas have different reflectivities, the plane of the movable plate is perpendicular to the emission light of the laser radar, and can be moved in a perpendicular direction relative to the laser radar. In the process of determining the pixel corresponding to the peak value of the light signal intensity, the pixel with the strongest signal can be determined.

[0104] In operation S610, for each scanning block, a row of pixels in at least one optical signal acquisition pixel array receives an optical signal from the scanning block within a time period to determine a pixel corresponding to an intensity peak of the optical signal, and to determine a measurement distance and an echo area of ​​the row of pixels.

[0105] In this embodiment, the calibration is performed with scanning blocks as units. Within a time period, the echo area and distance compensation value are calibrated for a reflectivity.

[0106] In operation S620, the following operations are repeated until the distance compensation value and echo area corresponding to each reflection area are obtained: the movable plate is moved so that each of the multiple reflection areas is aligned with the laser radar at different time periods; wherein the distance compensation value is the difference between the measured distance and the preset distance.

[0107] In this embodiment, the corresponding relationship between the distance compensation value and the echo area under different reflectivities can be obtained in different time periods.

[0108] In operation S630, the scanning blocks are switched and the above operations are repeated until distance compensation values ​​and echo areas corresponding to the scanning blocks at different reflectivities are obtained.

[0109] In this embodiment, the above operation can obtain the corresponding relationship between the echo area and the distance compensation value for each scanning block at different reflectivities. The data obtained by calibration is the corresponding relationship between the echo area and the distance compensation value for each scanning block. However, this data is discrete data.

[0110] In some embodiments, after obtaining the distance compensation value and echo area corresponding to each scanning block at different reflectivities, the method may further include the following operation: obtaining the distance compensation value corresponding to the uncalibrated echo area by interpolation calculation.

[0111] In order to obtain more comprehensive data covering the scene, some echo area data values ​​that have not been collected can be simulated and calculated, such as interpolation to obtain data that have not been experimentally obtained. Specifically, multiple interpolation methods can be used to obtain a smooth curve. The calibration data obtained after interpolation is as follows: Figure 8 shown.

[0112] In some embodiments, the method may further include the following operation: after obtaining the distance compensation value and the echo area, the scanning block number, the echo area and the distance compensation value of the scanning block are stored in a specific storage space in association with each other. This makes it easier for the laser radar to read the above association relationship from the specific storage space during operation, so as to compensate for the detected distance value.

[0113] Specifically, storing the scanning block number, echo area, and distance compensation value of the scanning block in a specific storage space in association with each other may include the following operations: storing the distance compensation value in the storage space of the scanning block corresponding to the scanning block number as a unit. The storage space uses the echo area as an index value and the distance compensation value as storage information. This facilitates accurate positioning of the required distance compensation value through the scanning block number and the echo area.

[0114] In some embodiments, the storage spaces of scanning blocks with adjacent scanning block numbers are adjacent, and the number of index values ​​of the storage spaces of all scanning blocks is equal to the number of pixels of the light signal acquisition pixel array. This makes it possible to index the distance compensation value for each pixel of a scanning block, with high compensation accuracy.

[0115] In some embodiments, since there may be two or more laser arrays, taking two laser arrays as an example, data can be stored in the following storage manner: One storage address in the storage space stores two distance compensation value pairs corresponding to the echo area, wherein the distance compensation value pair includes a left distance compensation value and a right distance compensation value.

[0116] In this embodiment, through the energy calibration process, the correspondence between the echo area and the distance compensation value for each scanning block can be obtained, which makes it convenient to determine the distance compensation value for each scanning block and echo area based on the correspondence to improve the accuracy of the laser radar ranging.

[0117] Another aspect of the present application also provides a method for improving the ranging accuracy of laser radar.

[0118] Fig. 9 This is a flow chart of a method for improving laser radar ranging accuracy shown in one embodiment of the present application.

[0119] For example, the laser radar includes at least one light signal acquisition pixel array and at least one laser array, each light signal acquisition array includes a plurality of pixels arranged in an array, and each laser array includes a plurality of scanning blocks. The energy calibration compensation value is stored in a 6912×128 RAM, and the compensation value is stored in units of scanning blocks, and each scanning block stores 128 compensation values ​​corresponding to energy. Among them, 6912 is the number of pixels, such as 96 pixel rows and 72 pixel columns. It should be noted that the size of the above RAM storage space is only for exemplary purposes and cannot be understood as a limitation on the present application.

[0120] See also Fig. 9 The method includes operations S910 to S930.

[0121] In operation S910, in response to obtaining a scanning block number and an echo area, a storage address in a storage space is determined, and the storage space stores a corresponding relationship between the scanning block number, the echo area, and the distance compensation value.

[0122] In this embodiment, during the operation of the laser radar, the scanning block number and the echo area information can be obtained, so that the corresponding distance compensation value can be found in the lookup table (LUT) based on these two types of information.

[0123] Specifically, in response to obtaining the scanning block number and the echo area, determining the storage address in the storage space may include the following operations: first, obtaining the starting scanning block number, the starting pixel number and the channel information. Then, based on the starting scanning block number, the starting pixel number and the channel information, determining the row address, column address and scanning block number of the pixel.

[0124] For example, in response to obtaining the scanning block number and echo area, determining the storage address in the storage space may include the following operations: if the obtained echo area successfully matches the echo area in the storage space, the storage address in the storage space is obtained based on the scanning block number and the obtained echo area.

[0125] Fig.10 This is a data flow diagram for improving the ranging accuracy of laser radar shown in an embodiment of the present application.

[0126] See also Fig.10 , calculate the row and column addresses of the pixel and the scanning block number to which it belongs based on the output starting scanning block (block_start), starting pixel (pixel_start) and cal_vld of the solution module received by the previous stage, and then determine the address of the compensation value in the RAM based on the calculated scanning block number and the input energy.

[0127] In operation S920, a distance compensation value is acquired from a storage space based on the storage address.

[0128] Specifically, the compensation value can be read out from the RAM according to the calculated address and then sent to the energy calibration distance compensation calculation unit for linear solution to calculate the compensation value.

[0129] In operation S930, the distance determined by the laser radar is compensated based on the distance compensation value. Specifically, the distance determined by the laser radar can be compensated by addition, subtraction, etc., to output a more accurate distance value.

[0130] It should be noted that, after compensating the distance determined by the laser radar based on the distance compensation value, the above method can also output the compensated distance from the pixel channel, where the pixel channel is a channel corresponding to the row address and column address of the pixel. Specifically, the distance information and energy value after compensation are finally classified according to the corresponding channel and output in the order of the pixel channel.

[0131] Fig.11 It is a schematic diagram of the data format shown in an embodiment of the present application.

[0132] See also Fig.11Each scanning block corresponds to a storage space, such as BLOCK0, BLOCK1...BLOCKn, etc. Each storage space BLOCK includes, for example, 128 distance compensation value data, and there is a corresponding relationship between each distance compensation value data and the echo area.

[0133] The interpolation calculation process is exemplified below.

[0134] In some embodiments, if the precise address value cannot be directly found, such as the input echo area falls between two echo areas in the lookup table, the distance compensation value corresponding to the input echo area can be calculated by interpolation.

[0135] Specifically, in response to obtaining the scanning block number and echo area, determining the storage address in the storage space may include the following operations: if the obtained echo area fails to match the echo area in the storage space, obtaining the storage addresses of the two echo areas in the storage space that are closest to the obtained echo area, so as to determine the distance compensation value corresponding to the obtained echo area by interpolation calculation based on the two echo areas closest to the obtained echo area and the two distance compensation values ​​corresponding to the two closest echo areas, wherein the two distance compensation values ​​corresponding to the two closest echo areas are obtained based on the storage addresses of the two echo areas closest to the obtained echo area.

[0136] Fig.12 It is a schematic diagram of the linear calculation compensation value of the energy calibration distance shown in an embodiment of the present application.

[0137] See also Fig.12 , the horizontal axis is the echo area (s), and the vertical axis is the distance compensation value (ds).

[0138] Fig.12 ds0, ds1, ds2, ds3, ds4, ds5, ds6, ds7, ds8, ds9, ds10, ds11, ds12, ds13, ds14, ... ds127 are the distance compensation values ​​obtained by looking up the table of 128 configurable energy values ​​(echo areas) s0 to s127. The size of the compensation value is uncertain, and the precision is an 8-bit unsigned char type value (u8). It depends on which interval the current s falls into, so as to linearly calculate the actual distance compensation value.

[0139] See also Fig.12 , assuming that s falls between s7 and s8, the compensation value falls between ds7 and ds8, and the solution of ds is shown in formula (1).

[0140]

[0141] By simplifying formula (1), we can get formula (2).

[0142]

[0143] Energy compensation is fixed-point u8 output. After the compensation value is obtained by table lookup, the final output is calculated and truncated and saturated, as shown in formula (3).

[0144] cac_energy_dst=cal_cfd_time+ds formula (3)

[0145] Combining equations (2) and (3), we can get the distance value solution as shown in equation (4).

[0146]

[0147] In this embodiment, the required distance compensation value can be obtained by interpolation without performing too much calibration work, which can reduce the calibration cost and improve the accuracy of the distance compensation value.

[0148] Fig.13 This is a data flow diagram for improving the ranging accuracy of laser radar shown in another embodiment of the present application.

[0149] See also Fig.13 A storage address in the storage space stores two distance compensation value pairs corresponding to the echo area, wherein the distance compensation value pair includes a left distance compensation value and a right distance compensation value.

[0150] Accordingly, in response to obtaining the scanning block number and the echo area, determining the storage address in the storage space may include the following operations.

[0151] First, obtain the starting scanning block number, starting pixel number and channel information, for example, the output block_start, pixel_start and cal_vld of the solution module received by the previous stage.

[0152] Then, the row address and column address of the pixel are determined based on the starting scanning block number, the starting pixel number and the channel information. For example, block_start, pixel_start and cal_vld are mapped to the row and column addresses of the pixel according to the address mapping rule.

[0153] Next, the distance compensation value selection direction is determined, and the adjusted echo area is obtained, the selection direction includes the left side or the right side, and the adjusted echo area is the multiplication result between the echo area and the preset coefficient. For example, calculate whether the pixel is on the left or the right side.

[0154] Then, based on the distance compensation value, the direction and the adjusted echo area are selected to obtain the distance compensation value from the storage space. Then, according to the input pixel energy, the energy coefficient is multiplied to read the RAM compensation value.

[0155] In addition, after reading the compensation value, it is sent to the energy calibration distance compensation to calculate the actual distance value and output it in pixel channel order.

[0156] In some embodiments, determining the row address and column address of a pixel based on the starting scanning block number, the starting pixel number, and the channel information may include the following operations.

[0157] First, the row address of the pixel is determined based on the lower 2 bits of the scanning block row counter and the scanning block channel counter.

[0158] Then, the column address of the pixel is determined based on the upper 2 bits of the scanning block channel counter.

[0159] Accordingly, determining the distance compensation value selection direction may include the following operations: if the value of the 6th bit of the multiplication result is 1, the left side is used as the distance compensation value selection direction, otherwise the right side is used as the distance compensation value selection direction, wherein the multiplication result is 24-bit data including a 7-bit decimal part, the multiplication result is the multiplication result of the 16-bit echo area and the 8-bit preset coefficient, and the 7-bit decimal part is processed using rounding.

[0160] The address mapping rules include row address rules and column address rules.

[0161] Regarding the row address, it consists of two counters, {block row counter, lower 2 bits of the channel counter in the block}, where the block row counter is determined by the configured row block number threshold and the current block counter. Each time the block counter reaches the configured threshold, the block row counter increases by 1.

[0162] Regarding the column address, it is first divided into 4 block_chn. In 1 block, add 1 at each pixel_start; in 1 row, add 8 at each block_start; return to the starting value (0, 8, 88, 96) when changing rows; select according to the high 2 bits of the channel counter chn_cnt.

[0163] Fig.14 It is a data format diagram shown in another embodiment of the present application.

[0164] See also Fig.14 , the data structure of the energy calibration RAM is as follows Fig.10As shown, the energy calibration table consists of a 4096*32 RAM, one storage address stores the distance compensation values ​​corresponding to 2 energies, and 4096 addresses can store the distance compensation values ​​corresponding to 8192 energies; each energy compensation value is divided into the left side and the right side; the energy calibration table is configured by the CPU through the bus interface.

[0165] The energy input from the previous module is 16 bits. Before looking up the table, it is multiplied by the configured energy coefficient. The energy coefficient is 8 bits, and the precision is u1.7 (including 7 decimal places). After multiplication, a 24-bit energy value is obtained, and the precision is u17.7. After multiplication, the decimal part is processed first, such as rounding. Determine whether bit[6] of the energy after multiplication is 1. If it is 1, the energy value bit[23:7]+1, otherwise the energy value is bit[23:7]. Finally, truncation and saturation processing is performed. Energy values ​​greater than 8191 are processed as 8191.

[0166] The compensation value of each pixel is obtained by looking up the table according to its own energy value and whether the pixel is on the left or right.

[0167] After the compensation value ds is obtained by table lookup, the final output is calculated and truncated and saturated. The formula is shown in formula (3).

[0168] In this embodiment, the detection distance is compensated based on the echo area, which effectively improves the distance measurement accuracy.

[0169] The temperature calibration process is exemplified below.

[0170] Since different scanning blocks have different corresponding relationships with different receiving blocks, when the temperature changes, different scanning blocks will have different distance changes, and different receiving blocks will also have different distance changes, and the scanning blocks will map different receiving blocks as the distance changes. In this way, when the temperature changes, the different mappings of the scanning blocks and the receiving blocks are coupled together. If the temperature of each receiving pixel and each transmitting cell varies greatly with the temperature, this will be a very difficult problem.

[0171] In the following, it is taken as an example that a laser radar includes at least one optical signal acquisition pixel array and a plurality of scanning blocks, each optical signal acquisition array includes a plurality of pixels arranged in an array, and each scanning block includes at least one laser.

[0172] Fig.15 It is a schematic diagram of a temperature calibration process shown in an embodiment of the present application.

[0173] See also Fig.15 The temperature calibration process may include operations S1510 to S1520.

[0174] In operation S1510, the following operations are repeated until distance compensation values ​​corresponding to a plurality of different target temperatures are determined: for a current target temperature, a third distance compensation value for each scanning block at the current target temperature is determined; and switching to a next target temperature is performed.

[0175] In this embodiment, in order to obtain the distance compensation value, the two methods shown can be used.

[0176] For example, one solution is to explore the temperature change characteristics of each pixel of the receiving sensor, and explore the temperature change characteristics of each cell of the transmitting Vcsel, and then make further decisions.

[0177] Specifically, determining the third distance compensation value for each scanning block at the current target temperature may include the following operations.

[0178] First, adjust the temperature of the laser radar to the current target temperature. The current target temperature may be the temperature that needs to be calibrated.

[0179] Then, a fourth distance compensation value for each pixel at the current target temperature is determined, and a fifth distance compensation value for each scanning block at the current target temperature is determined.

[0180] Next, a third distance compensation value is determined based on the fourth distance compensation value and the fifth distance compensation value.

[0181] For example, one solution is to directly carry out the calibration work. The calibration method is to use an external light source to heat and calibrate only the receiving sensor. First, calibrate the temperature curve of each pixel of the receiving sensor, and then use the known pixel temperature curve to calibrate the entire device.

[0182] Specifically, determining the third distance compensation value for each scanning block at the current target temperature may include the following operations.

[0183] First, the temperature of the light signal acquisition pixel array is adjusted to the current target temperature.

[0184] Then, a standard light source is used to emit laser light to determine a fourth distance compensation value for each pixel at the current target temperature.

[0185] Next, a laser is used to emit laser light to determine a third compensation value for each scanning block at the current target temperature, wherein the distance information output by each pixel of the optical signal acquisition pixel array is compensated by a fourth distance compensation value.

[0186] In some embodiments, adjusting the temperature of the light signal acquisition pixel array to the current target temperature may include: using a heating fan or a low temperature box to adjust the temperature of the light signal acquisition pixel array to the current target temperature.

[0187] Fig.16 It is a structural schematic diagram of a temperature calibration platform shown in an embodiment of the present application. Fig.17 It is a structural schematic diagram of a temperature calibration platform shown in another embodiment of the present application.

[0188] See also Fig.16 and Fig.17 , mainly through the equipment to heat or cool the laser radar, so that the laser radar works in a specific temperature range, and then test the influence of temperature on the ranging accuracy, so as to eliminate the influence of temperature on the ranging accuracy. For example, a heating fan can be used to heat the laser radar to a specific operating temperature. For example, a low temperature box can be used to cool the laser radar to a specific low temperature working environment. For example, high temperature is mainly used in production, and the exploration of low temperature is used for low temperature curve fitting interpolation calculation after production.

[0189] In operation S1520, the index value of the scanning block, the target temperature, and the third distance compensation value are associated and stored so as to determine a temperature distance compensation value corresponding to the target temperature based on the third distance compensation value.

[0190] Since the storage space is limited, in order to avoid excessive costs due to the lookup table occupying too much storage space, different storage strategies can be adopted for the compensation values ​​of the commonly used temperature range and the uncommon temperature range.

[0191] In some embodiments, for commonly used temperature ranges, if the distance compensation value needs to be accurate, more storage space can be allocated to store as much calibration data as possible. Specifically, storing the index value of the scanning block, the target temperature, and the third distance compensation value in association can include: for the index value of each scanning block, for the first preset temperature range, determining the third storage address corresponding to each target temperature according to the preset temperature interval and the index value of the current scanning block; and storing the distance compensation value corresponding to each target temperature according to the third storage address.

[0192] In some embodiments, for an uncommon temperature range, such as a low temperature range, while maintaining the accuracy of the compensation data, it is necessary to reduce the storage space occupied to reduce production costs, and a mathematical model can be stored to calculate the distance compensation value. Specifically, the associated storage of the index value of the scanning block, the target temperature, and the third distance compensation value can also include the following operations: for each scanning block index value, for the second preset temperature range, based on the fourth storage address, the first preset temperature slope and the first temperature offset value are stored.

[0193] In some embodiments, for uncommon temperature intervals, such as high temperature intervals, the associated storage of the index value of the scanning block, the target temperature, and the third distance compensation value may also include the following operations: for each scanning block index value, for the third preset temperature range, the second preset temperature slope and the second temperature offset value are stored based on the fifth storage address.

[0194] The first preset temperature range is higher than the second preset temperature range, and the first preset temperature range is lower than the third preset temperature range.

[0195] In this embodiment, for uncommon temperature intervals, a distance compensation value corresponding to the current temperature is calculated by storing a mathematical model, which can effectively reduce the storage cost of the distance compensation value for uncommon temperature intervals while ensuring the distance compensation accuracy for commonly used temperature intervals.

[0196] Accordingly, the distance compensation value corresponding to the temperature may be retrieved and distance compensation may be performed in the following manner.

[0197] Fig.18 This is a data flow diagram for improving the ranging accuracy of laser radar shown in another embodiment of the present application.

[0198] See also Fig.18 , the above method may also include the following operations.

[0199] First, in response to obtaining the index value and temperature information of the scan block, a third storage address in the storage space is determined. The temperature interval may include a common temperature interval and an uncommon temperature interval. For example, an uncommon temperature interval includes a high temperature interval and a low temperature interval. Different storage strategies may be used for the distance compensation values ​​corresponding to the common temperature interval and the uncommon temperature interval.

[0200] Then, a third distance compensation value is obtained from the storage space based on the third storage address.

[0201] Next, the distance determined by the laser radar is compensated based on the third distance compensation value.

[0202] In some embodiments, for a common temperature range, obtaining a third distance compensation value from a storage space based on a third storage address may include the following operations: if the temperature information is within a first preset temperature range, using the storage data of the third storage address in the storage space as the third distance compensation value.

[0203] In some embodiments, for an uncommon temperature range, obtaining a third distance compensation value from a storage space based on a third storage address may include the following operations.

[0204] For example, if the temperature information is within the second preset temperature range, the storage data of the fourth storage address in the storage space is used as the first preset temperature slope and the first temperature offset value; and the third distance compensation value is calculated based on the distance compensation value corresponding to the lowest temperature in the second preset temperature range, the first preset temperature slope and the first temperature offset value.

[0205] For example, if the temperature information is within a third preset temperature range, the storage data at the fifth storage address in the storage space is used as the second preset temperature slope and the second temperature offset value; and the third distance compensation value is calculated based on the distance compensation value corresponding to the highest temperature in the second preset temperature range, the second preset temperature slope and the second temperature offset value.

[0206] The first preset temperature range is higher than the second preset temperature range, and the first preset temperature range is lower than the third preset temperature range.

[0207] Fig.19 It is a data format diagram shown in another embodiment of the present application.

[0208] See also Fig.19 , the compensation value obtained by temperature calibration can be stored in a specific storage space (such as a RAM of 6912*108 size). The compensation value is stored in units of scan blocks, and each scan block stores the compensation value corresponding to -40 to 150°C, of ​​which the low temperature -40 to -1°C stores the low temperature slope and low temperature offset value, and the high temperature 86 to 150°C stores the high temperature slope and high temperature offset value. The address of the compensation value in RAM is calculated according to the input scan block number (block number) and the current temperature value, and the compensation value is read from the RAM according to the calculated address and sent to the temperature calibration distance compensation calculation unit for linear solution to calculate the compensation value, and finally the distance information after compensation is sequentially output. It should be noted that the high temperature range and low temperature range shown above are only exemplary descriptions and cannot be understood as limitations on the present application.

[0209] Specifically, the distance compensation calculation process can be as follows. For example, the processing process according to different temperatures is as follows.

[0210] If the temperature is in the range of 0 to 85°C, the RAM address is generated and the compensation value dt is selected according to the temperature and block number.

[0211] If the temperature is within the range of -40 to -1°C, the compensation value dt is calculated according to the formula dt=a*x+b, where a is the low temperature slope cfg_cold_slope, b is the low temperature offset value cfg_cold_offset, and x is the input temperature.

[0212] If the temperature is within the range of 85-150° C., the compensation value dt is calculated according to the formula dt=a*x+b, where a is the high temperature slope cfg_hot_slope, b is the high temperature offset value cfg_hot_offset, and x is the input temperature.

[0213] Both a and b are 10 bits, bit[9] is the sign bit, bit[8:0] is the value, the precision is S4.6, and a and b are signed numbers.

[0214] After obtaining the compensation value through table lookup or calculation, the final output is calculated and saturation truncation is performed. The calculation formula is shown in formula (5).

[0215]

[0216] In this embodiment, by calibrating the corresponding relationship between temperature and distance compensation value, the ranging accuracy of the laser radar in different temperature environments is effectively improved.

[0217] The absolute distance calibration process is exemplified below.

[0218] Fig. 20 It is a schematic diagram of an absolute distance calibration process shown in an embodiment of the present application.

[0219] See also Fig. 20 The method includes operations S2010 to S2020.

[0220] In operation S2010, the following operations are repeated until distance compensation values ​​corresponding to multiple different target distances are determined: for the current target distance, a first distance compensation value for each pixel at the current target distance is determined, and\or, a second distance compensation value for each scanning block at the current target distance is determined; and switching to the next target distance.

[0221] In operation S2020, the index value of each pixel, each target distance, and the first distance compensation value are stored in association, and / or the index value of each scanning block, each target distance, and the second distance compensation value are stored in association.

[0222] In this embodiment, the index value of a pixel is related to the position of the pixel in the light signal acquisition pixel array, and / or, the index value of a scanning block is related to the position of the scanning block in multiple scanning blocks.

[0223] For example, the position information may be determined by a row index value and a column index value.

[0224] Specifically, for a pixel, associatively storing the index value of each pixel, each target distance, and the first distance compensation value may include the following operations.

[0225] First, the position information of the pixel in the light signal acquisition pixel array is converted into a first row index value, and a plurality of different target distances are converted into a first column index value.

[0226] Then, a first storage address is determined based on the first row index value and the first column index value.

[0227] Next, the first distance compensation value is stored according to the first storage address.

[0228] For the scanning blocks, associatively storing the index value of each scanning block, each target distance, and the second distance compensation value may include the following operations.

[0229] First, the position information of the scanning block in the plurality of scanning blocks is converted into a second row index value, and the plurality of different target distances are converted into a second column index value.

[0230] Then, a second storage address set is determined based on the second row index value and the second column index value.

[0231] Next, a second distance compensation value is stored based on a second storage address set.

[0232] The following is an exemplary description of the use process of the absolute distance calibration result. Take the example of a laser radar including at least one optical signal acquisition pixel array and a plurality of scanning blocks, each optical signal acquisition array including a plurality of pixels arranged in an array, and each scanning block including at least one laser.

[0233] Fig.21 This is a data flow diagram for improving the ranging accuracy of laser radar shown in another embodiment of the present application.

[0234] See also Fig.21 , the method of improving the laser radar ranging accuracy may include the following operations.

[0235] First, in response to obtaining an index value and first distance information of a pixel, a first storage address in a storage space is determined, and\or, in response to obtaining an index value and second distance information of a scan block, a second storage address in the storage space is determined.

[0236] Then, the first distance compensation value and / or the second distance compensation value are acquired from the storage space based on the first storage address and / or the second storage address.

[0237] Next, the distance determined by the laser radar is compensated based on the first distance compensation value and / or the second distance compensation value.

[0238] Specifically, a table is looked up according to the received distance information, and after the corresponding result is found, it is sent to the distance calibration compensation unit to solve the compensation value, and finally the solved distance compensation data is added to the input distance for output.

[0239] Fig. 22 It is a data format diagram shown in another embodiment of the present application.

[0240] For example, the absolute distance compensation lookup table (LUT) is a distance compensation data table obtained in advance according to the target distance D and the pixel position (vcsel cell position) test. Fig. 22 As shown in the left figure, one storage address corresponds to one pixel, and each pixel stores distance compensation values ​​dist0 to dist7 corresponding to 8 distance points.

[0241] For another example, the absolute distance compensation LUT is a distance compensation data table obtained in advance based on the target distance D and the Block position test. Fig. 22 As shown in the figure on the right, one storage address corresponds to one block, and each block stores the distance compensation values ​​dist0 to dist7 corresponding to 8 distance points, and the distance compensation data has a higher accuracy. The distance points can also be set to 6.

[0242] Since the calibration result is discrete data, when performing a table lookup, the distance compensation value corresponding to the distance may be directly found, or the distance compensation value corresponding to the distance may not be directly found.

[0243] In some embodiments, for a scenario in which a distance compensation value corresponding to a distance can be directly found, a first storage address in a storage space is determined in response to obtaining an index value of a pixel and first distance information, including: if the obtained first distance information successfully matches the distance information in the storage space, then obtaining the first storage address in the storage space based on the index value of the pixel and the first distance information.

[0244] In some embodiments, in response to obtaining an index value and second distance information of a scanning block, determining a second storage address in a storage space includes: if the obtained second distance information successfully matches the distance information in the storage space, obtaining the second storage address in the storage space based on the index value and second distance information of the scanning block.

[0245] In some embodiments, for a scenario in which the distance compensation value corresponding to the distance cannot be directly found, in response to obtaining the index value of the pixel and the first distance information, determining the first storage address in the storage space also includes: if the obtained first distance information fails to match the distance information in the storage space, obtaining the first storage address of each of the two distance information closest to the obtained first distance information in the storage space, so as to determine the distance compensation value corresponding to the first distance information by interpolation calculation based on the two distance information closest to the obtained first distance information and the distance compensation values ​​corresponding to the two closest distance information, wherein the distance compensation values ​​corresponding to the two closest distance information are obtained based on the first storage addresses of each of the two distance information closest to the obtained first distance information.

[0246] For another example, in response to obtaining the index value and the second distance information of the scanning block, determining the second storage address in the storage space also includes: if the obtained second distance information fails to match the distance information in the storage space, obtaining the second storage addresses of the two distance information closest to the obtained second distance information in the storage space, so as to determine the distance compensation value corresponding to the second distance information by interpolation calculation based on the two distance information closest to the obtained second distance information and the distance compensation values ​​corresponding to the two closest distance information, wherein the distance compensation value corresponding to the two closest distance information is obtained based on the second storage addresses of the two distance information closest to the obtained second distance information.

[0247] Fig.23 It is a schematic diagram of a distance compensation value calculation process shown in another embodiment of the present application.

[0248] See also Fig.23 , dist0, dist1, dist2, dist3, dist4, dist5, dist6, dist7 are the distance compensation values ​​obtained by looking up the table of the current input distance value cac_temperature_dst=D at a specific distance, and see which interval the current D falls in, so as to linearly calculate the distance compensation value dcal. As shown in the figure, assuming that D falls between d3 and d4, the distance compensation value falls between dist3 and dist4, and the solution of dcal is shown in formula (6).

[0249]

[0250] By transforming equation (6), we can get equation (7).

[0251]

[0252] The distance compensation DCAL is fixed-pointed to the S12 output.

[0253] After the compensation value is obtained by table lookup, the final output is calculated and saturated. The calculation result is u16. The calculation formula of the distance value after compensation is shown in formula (8).

[0254] cac_dist_dst=cac_temperature_dst+dcal formula (8)

[0255] In this embodiment, the distance compensation value corresponding to the current distance is obtained through the calibration result of the distance calibration, which can effectively improve the accuracy of the distance measurement results of the laser radar test of target objects at different distances from the laser radar.

[0256] Another aspect of the present application also provides a circuit diagram for calculating distance.

[0257] Fig.24 It is a schematic diagram of a pipeline structure for calculating distance shown in an embodiment of the present application. Fig.24 The interpolation calculation circuit shown introduces a multi-level register to speed up the calculation and improve the problem of wasting a lot of waiting time due to the different processing speeds of each branch during the calculation process.

[0258] See also Fig.24 The interpolation calculation circuit 2400 may include: a data acquisition circuit, a selection circuit, a subtraction circuit, a division circuit, a multiplication circuit and an addition circuit.

[0259] The data acquisition circuit includes a register for storing distance information and storage address information.

[0260] The selection circuit SEL is used to select an addition operation or a subtraction operation.

[0261] The subtraction circuit SUB is used to calculate a first difference, a second difference and a third difference, wherein the first difference is the difference between two distance information closest to the obtained first distance information, the second difference is the difference between the distance compensation values ​​corresponding to the two closest distance information, and the third difference is the difference between the first distance information and the smaller value of the two closest distance information.

[0262] The division circuit DIV is used to calculate a division result between the second difference and the first difference.

[0263] The multiplication circuit MUL is used to calculate a multiplication result between the division result and the third difference.

[0264] An adding circuit ADD, used for calculating an addition operation result between the distance information and the multiplication operation result according to the selection result of the selection circuit;

[0265] Among them, the output circuit of at least one of the selection circuit, the subtraction circuit, the division circuit, the multiplication circuit, and the addition circuit is a register circuit.

[0266] The formula that needs explanation, Fig.24 Six levels of delay are used in the circuit, and the number of delay levels can be reduced according to the computing speed requirements, such as not applying at least one of the third-level delay, the fourth-level delay, and the fifth-level delay. By using multiple levels of delay, the frequency of the circuit can be effectively increased. For example, as long as the registers of multiple parallel branches have collected completion information, the processing results can be transmitted to the next level, without setting too long a waiting time to wait for multiple parallel branches to complete the current level of calculation.

[0267] Registers are small storage areas used to store data, such as temporarily storing data involved in operations and operation results. Registers are essentially a sequential logic circuit, but this sequential logic circuit only contains storage circuits. The storage circuit of a register is composed of latches or flip-flops (FF for short). A latch or flip-flop can store 1 bit of binary number, and N latches or flip-flops can form an N-bit register group. Register groups can be designed according to the number of bits in a byte in a computer, for example, 8-bit register groups, 16-bit register groups, etc.

[0268] Latches and flip-flops are both logic circuits with storage functions and are the basic logic units that constitute sequential circuits. Latches are circuits that are sensitive to pulse levels and change their states under a certain level. Flip-flops are circuits that are sensitive to the edge of clock pulses and change their states under the rising or falling edge of clock pulses. Flip-flops are classified by logic function into D flip-flops, JK flip-flops, T flip-flops, and SR flip-flops.

[0269] A D flip-flop is taken as an example for illustration.

[0270] The flip-flop is sensitive to pulse edges, and its state changes only at the rising or falling edge of the clock pulse. A flip-flop, also called a bistable gate or a bistable flip-flop, is a digital logic circuit that can operate in two states. The flip-flops maintain their state until they receive an input pulse, also called a trigger. When an input pulse is received, the flip-flop output changes state according to the rules, and then maintains this state until another trigger is received. The flip-flop has the following characteristics: the clock is valid later than the data, which means that the data signal is established first, the clock signal is established later, and is stored in the flip-flop at the valid edge (such as the rising edge or the falling edge).

[0271] In this embodiment, this module adopts a six-stage pipeline structure to implement the above calculation process, namely, data acquisition, selection, subtraction, division, multiplication, and addition. The data generates a total of six levels of delay, which can effectively increase the frequency of the circuit and thus increase the interpolation calculation speed.

[0272] The following is an exemplary description of the calibration process and calculation process of the reflectivity.

[0273] Fig.25 This is a reflectivity calibration flow chart shown in an embodiment of the present application.

[0274] See also Fig.25 As shown, the method for calibrating a laser radar includes operations S2510 to S2530.

[0275] In operation S2510, the following operations are repeated until Q first correspondences are obtained: a first correspondence between the echo area and the distance information under the target reflectivity is calculated based on the parameters of the laser radar, where Q is an integer greater than 2.

[0276] In this embodiment, a theoretical simulation is first performed according to the radar equation to obtain a reflectivity curve.

[0277] Fig.26 It is a data curve of echo area and distance under different reflectivity shown in an embodiment of the present application.

[0278] See also Fig.26 , showing the corresponding relationship between echo area and distance under reflectivity of 10%, 50% and 80%. Then the curve is converted into RAM data. The input of RAM data is area and distance, and the output is reflectivity. In the simulation, the three data of 10%, 50% and 80% are first obtained, and the reflectivity in other intervals is calculated by interpolation. Correspondingly, the value of Q can be 3.

[0279] In operation S2520, by changing the distance between the reflective plate having the target reflectivity and the laser radar, a second correspondence between the echo area and the distance information under the target reflectivity is tested.

[0280] In this embodiment, the data curves of echo area and distance under different standard reflectivities can be measured by the reflectivity calibration platform. The measured data curve and the simulated data curve may not completely overlap, and the difference between the two can be used to correct the reflectivity determined by the laser radar.

[0281] In operation S2530, reflectivity compensation related parameters are determined based on the difference between the first correspondence and the second correspondence to adjust the reflectivity of the laser radar output based on the reflectivity compensation related parameters.

[0282] The reflectivity compensation parameters are various parameters that can be used to compensate for reflectivity, such as echo area coefficient, reflectivity compensation coefficient, etc. In a specific embodiment, the reflectivity compensation related parameters include echo area compensation coefficient, and one echo area compensation coefficient is used to compensate at least one echo area.

[0283] In some embodiments, the second corresponding relationship is determined by a reflectivity calibration platform.

[0284] The reflectivity calibration platform includes a movable guide rail and a standard reflectivity plate arranged on the movable rail. By changing the position of the standard reflectivity plate on the rail, the distance between the reflective plate of the target reflectivity and the laser radar is changed.

[0285] Fig. 27 It is a structural schematic diagram of a reflectivity calibration platform shown in one embodiment of the present application.

[0286] See also Fig. 27 , reflectivity calibration mainly calibrates the relationship curve between area, distance and standard reflectivity. Place the standard reflectivity plate (such as reflectivity of 10%, 50%, 80%) on the movable rail. Then adjust the position of the reflectivity plate and collect different relationship curves. Then convert the obtained curve and store it in the memory. After calculating the distance and amplitude, perform reflectivity table lookup and interpolation calculation.

[0287] In some embodiments, the second correspondence may be stored in a two-dimensional lookup table, wherein one storage address corresponds to an echo area corresponding to Q reflectivities, and the echo area is Q discrete values. It should be noted that each standard reflectivity corresponds to a two-dimensional lookup table.

[0288] The table lookup process is exemplified below.

[0289] Fig.28 This is a data flow diagram for improving the ranging accuracy of laser radar shown in another embodiment of the present application.

[0290] See also Fig.28 The method for improving the accuracy of laser radar reflectivity measurement may include: operations S2810 to S2820.

[0291] In operation S2810, in response to obtaining distance information and detecting echo areas, echo areas corresponding to the distance signal and Q target reflectivities are determined based on a first correspondence relationship, where the first correspondence relationship is a correspondence relationship between the echo area and the distance information at the target reflectivity.

[0292] For example, the reflectivity calibration LUT is two-dimensional: distance 0 to 2687, energy, where energy is 4 discrete unsigned fixed-point u16 data.

[0293] In operation S2820, a reflectivity corresponding to the detection echo area is calculated based on the Q echo areas and the reflectivities corresponding to the respective Q echo areas.

[0294] In some embodiments, the distance information is m-bit data, where m is an integer greater than 2.

[0295] Fig.29 It is a schematic diagram of a reflectivity calibration lookup table shown in an embodiment of the present application.

[0296] See also Fig.29 The reflectivity calibration lookup table consists of a lookup table stored in a specific size of storage space. For example, a memory of size 2688*64bit is used, and one storage address stores the energy value corresponding to four reflectivities (r0, r1, r2, r3). ​​When powered on, the reflectivity table is configured by the CPU through the memory read-write bus interface. In normal working mode, the CPU can read memory data.

[0297] Fig.30 It is a schematic diagram of a process for solving the echo area corresponding to the standard reflectivity and distance shown in an embodiment of the present application.

[0298] See also Fig.30 In response to obtaining the distance information and detecting the echo area, determining the echo areas corresponding to the distance signal and the Q target reflectivities based on the first corresponding relationship may include the following operations.

[0299] First, high p-bit data among m-bit data is obtained, where p is an integer greater than 1 and p is less than m.

[0300] Then, Q echo areas corresponding to the high p-bit data and the Q target reflectivities are determined based on the Q first correspondences.

[0301] It should be noted that the input distance may or may not be directly matched in the lookup table. If it is not directly matched, the relevant echo area can be determined by a special calculation method, and then the reflectivity can be calculated based on the corresponding relationship between the echo area and the reflectivity.

[0302] Since the reflectivity calibration data is relatively small, it is highly likely that the exact echo area cannot be directly matched. The following is an example of a scenario where the exact echo area cannot be directly matched.

[0303] In some embodiments, determining Q echo areas corresponding to high p-bit data and Q target reflectivities based on the Q first correspondences may include the following operations.

[0304] First, determine the two distance information adjacent to the high p-bit data in the first corresponding relationship. Among them, the value of p can depend on the accuracy of the laser radar before the reflectivity calibration is performed. For example, the higher the accuracy of the laser radar, the more accurate bits there are in the echo area (the high-order bits represent the high bits in the data, that is, the approximate range, and the low-order bits represent the low bits in the data, such as the fine range). If the accuracy is higher, fewer bits need to be calibrated. For example, if the accuracy of the high 12 bits [15:4] in the 16-bit data is high enough, then the calibration of the low 4 bits [3:0] data is mainly considered. The above processing method can effectively reduce the amount of calibration calculations, save resources and reduce costs.

[0305] Then, based on the Q first corresponding relationships, (2×Q) echo areas corresponding to the two distance information and Q target reflectivities are determined. Among them, for the scene with a reflectivity calibration lookup table with four standard reflectivities, one distance value can obtain two adjacent distance values, one large and one small. Each adjacent distance value corresponds to Q echo areas. Therefore, (2×Q) echo areas can be obtained.

[0306] Next, based on the (2×Q) echo areas, Q interpolation echo areas corresponding to the data other than the high p-bit data in the m-bit data are obtained through interpolation calculation.

[0307] In some embodiments, determining (2×Q) echo areas corresponding to two pieces of distance information and Q target reflectivities based on Q first correspondences may include the following operations.

[0308] Based on the Q first correspondences, Q first echo areas corresponding to the high p-bit data and the Q target reflectivities are determined, and based on the Q first correspondences, Q second echo areas corresponding to the high (p+1)-bit data in the m-bit data and the Q target reflectivities are determined.

[0309] According to the received distance information, the energy under a specific reflectivity is obtained by looking up the table. If the distance is between two LUT addresses, the 8 energy values ​​corresponding to the upper and lower addresses are found; then the 4 energy values ​​corresponding to the input distance are linearly interpolated according to the energy values ​​obtained from the table. According to the input reflection energy S and the adjacent reflection energy intervals (Sn, Sn-1), the reflectivity is calculated by linear interpolation.

[0310] For example, see Fig.30, s0_near, s1_near, s2_near, s3_near are four energy values ​​obtained by looking up the table of the upper 12 bits [15:4] of the current input distance value cac_dist_dst, corresponding to the four reflectivities of r0, r1, r2, and r3. s0_far, s1_far, s2_far, s3_far are four energy values ​​obtained by looking up the table of the upper 12 bits [15:4]+1 of the current input distance value cac_dist_dst, corresponding to the four reflectivities of r0, r1, r2, and r3. The corresponding s0_insert, s1_insert, s2_insert, and s3_insert are calculated by linear interpolation of the lower 4 bits [3:0] of the input distance value cac_dist_dst.

[0311] s 0_near ≥s 0_far When , use equations (9) to (12) for calculation.

[0312]

[0313]

[0314]

[0315]

[0316] s 0_near < 0_far When , equations (13) to (16) are used for calculation.

[0317]

[0318]

[0319]

[0320]

[0321] Then see which interval the current input energy s falls into, and linearly calculate the actual reflectivity R value.

[0322] Accordingly, based on Q echo areas and the reflectivities corresponding to each of the Q echo areas, calculating the reflectivity corresponding to the detected echo area may include the following operations: determining the reflectivity corresponding to the detected echo area based on Q interpolated echo areas and the reflectivities corresponding to each of the Q interpolated echo areas.

[0323] Fig.31 It is a schematic diagram of a process of solving reflectivity by interpolation, shown in one embodiment of the present application.

[0324] See also Fig.31 Based on the Q interpolated echo areas and the Q standard reflectivities, determining the reflectivity corresponding to the detected echo area may include the following operations.

[0325] First, two target interpolation echo areas adjacent to the detection echo area among the Q interpolation echo areas are determined.

[0326] Then, two standard reflectivities corresponding to the two target interpolation echo areas are determined.

[0327] Next, based on the two target interpolation echo areas and the two standard reflectivities, the reflectivity corresponding to the detection echo area is calculated.

[0328] See also Fig.31 Assuming that s falls between s1_insert and s2_insert, the reflectivity R falls between 45% and 90%, and the solution of R is equation (17).

[0329]

[0330] Formula (17) can be simplified to Formula (18).

[0331]

[0332] The reflectivity R is fixed-point output by u8.

[0333] Another aspect of the present application also provides an interpolation circuit.

[0334] Fig.32 It is a schematic diagram of a pipeline structure for calculating reflectivity shown in an embodiment of the present application.

[0335] See also Fig.32 , the reflectivity corresponding to the detected echo area is calculated through a specific circuit; the specific circuit includes: a data acquisition circuit, a selection circuit SEL, a subtraction circuit SUB, a division circuit DIV, a multiplication circuit MUL and an addition circuit ADD.

[0336] The data acquisition circuit includes a register for storing distance information and detecting echo area.

[0337] The selection circuit is used to select addition operation or subtraction operation.

[0338] The subtraction circuit is used to calculate a first subtraction result between two standard reflectivities corresponding to two target interpolation echo areas, a second subtraction result between the two target interpolation echo areas, and a third subtraction result between the detection echo area and the smaller value of the two target interpolation echo areas.

[0339] The division circuit is used to calculate a division result between the first subtraction result and the second subtraction result.

[0340] The multiplication circuit is used to calculate a multiplication result between the division operation result and the third subtraction operation result.

[0341] The adding circuit is used to calculate the addition result between the multiplication result and the smaller value of two standard reflectivities corresponding to the two target interpolation echo areas according to the selection result of the selection circuit.

[0342] Among them, the output circuit of at least one of the selection circuit, the subtraction circuit, the division circuit, the multiplication circuit, and the addition circuit is a register circuit.

[0343] In this embodiment, a six-stage pipeline structure is used to implement the above calculation process, which includes data acquisition, selection, subtraction, division, multiplication, and addition, and the data generates a total of six levels of delay, which can effectively improve the calculation speed.

[0344] In some embodiments, the echo area may be corrected to further improve the accuracy of the reflectivity calculation. Specifically, the laser radar stores reflectivity compensation related parameters.

[0345] After determining (2×Q) echo areas corresponding to two distance information and Q target reflectivities based on Q first corresponding relationships, the method further includes: compensating the (2×Q) echo areas based on reflectivity compensation related parameters to obtain compensated (2×Q) echo areas.

[0346] Accordingly, based on the (2×Q) echo areas, obtaining Q interpolated echo areas corresponding to the data other than the high p-bit data in the m-bit data through interpolation calculation may include the following operation: based on the compensated (2×Q) echo areas, obtaining Q interpolated echo areas corresponding to the data other than the high p-bit data in the m-bit data through interpolation calculation.

[0347] Fig.33 It is a schematic diagram of the process of solving the echo area corresponding to the standard reflectivity and distance shown in another embodiment of the present application. Fig.34 It is a schematic diagram of the data format of the reflectivity calibration coefficient shown in an embodiment of the present application.

[0348] See also Fig.33 and Fig.34 , Fig.30 The data found by the reflectivity calibration LUT needs to be multiplied by the coefficient value to make the calibration value more accurate. Fig.33 The following table shows the coefficients required for the reflectivity calibration module, which are stored in units of 4x4 pixels. The s0_insert in subsequent calculations is multiplied by the corresponding coefficients.

[0349] Another aspect of the present application also provides a circuit for improving the ranging accuracy of laser radar.

[0350] The laser radar includes at least one optical signal acquisition pixel array and at least one laser array, each optical signal acquisition array includes a plurality of pixels arranged in an array, each laser array includes a plurality of scanning blocks, and the circuit includes:

[0351] The storage address determination circuit is used to determine the storage address in the storage space in response to obtaining the scanning block number and the echo area, and the storage space stores the corresponding relationship between the scanning block number, the echo area and the distance compensation value.

[0352] The compensation value acquisition circuit is used to acquire the distance compensation value from the storage space based on the storage address.

[0353] The distance compensation circuit is used to compensate the distance determined by the laser radar based on the distance compensation value.

[0354] Another aspect of the present application provides another circuit for improving the ranging accuracy of laser radar.

[0355] Fig.35 A circuit for improving the ranging accuracy of a laser radar is shown in an embodiment of the present application.

[0356] See also Fig.35 The laser radar includes at least one optical signal acquisition pixel array and a plurality of scanning blocks, each optical signal acquisition array includes a plurality of pixels arranged in an array, each scanning block includes at least one laser, and the circuit 3500 includes:

[0357] The storage address determination circuit 3510 is used to determine a first storage address in the storage space in response to obtaining an index value and first distance information of a pixel, and\or, to determine a second storage address in the storage space in response to obtaining an index value and second distance information of a scanning block.

[0358] The compensation value acquisition circuit 3520 is used to acquire the first distance compensation value and / or the second distance compensation value from the storage space based on the first storage address and / or the second storage address.

[0359] The distance compensation circuit 3530 is used to compensate the distance determined by the laser radar based on the first distance compensation value and / or the second distance compensation value.

[0360] Another aspect of the present application provides another circuit for improving the ranging accuracy of laser radar.

[0361] Fig.36 A circuit for improving the accuracy of reflectivity measurement by a laser radar is shown in an embodiment of the present application.

[0362] See also Fig.36 The circuit 3600 for improving the accuracy of laser radar reflectivity measurement includes:

[0363] The correspondence determination circuit 3610 is used to determine the echo areas corresponding to the distance signal and Q target reflectivities based on a first correspondence in response to obtaining distance information and detecting echo areas. The first correspondence is the correspondence between the echo area and the distance information under the target reflectivity.

[0364] The reflectivity calculation circuit 3620 is used to calculate the reflectivity corresponding to the detection echo area based on the Q echo areas and the reflectivities corresponding to the Q echo areas.

[0365] It should be noted that logical operations include but are not limited to: "OR", "AND", "NOT", "NOR", "NAND", "XOR", etc. Logic operation circuits include but are not limited to: "OR operation circuit", "AND operation circuit", "NOT operation circuit", "NOR operation circuit", "NAND operation circuit", "XOR operation circuit", etc. These logic operation circuits may also be referred to as logic operation units. In order to compare whether two values ​​are the same, a combination of multiple logic operation circuits may be used to implement this, and accordingly, a combination of multiple logic operation circuits may be used to implement this, which is not limited here.

[0366] Another aspect of the present application also provides a chip. The chip may include a clock circuit as described above, and a functional circuit that implements a specific function based on a clock signal output by the clock circuit. The functional circuit includes but is not limited to: a processor, a transmitter, a receiver, etc.

[0367] In a possible implementation, another aspect of the present application further provides a board, which includes a storage device, an interface device, a control device and the above-mentioned chip. The chip is connected to the storage device, the control device and the interface device respectively. The storage device is configured to store data. The interface device is configured to realize data transmission between the artificial intelligence chip and the external device. The control device is configured to monitor the status of the artificial intelligence chip.

[0368] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated again here.

[0369] Another aspect of the present application further provides a radar. The radar may include the chip or board as described above.

[0370] Fig.37 It is a schematic diagram of the structure of a radar shown in an embodiment of the present application.

[0371] See also Fig.37, the radar 3700 may include a chip or board as shown above, and the chip and / or board may include a clock circuit as described above. Specifically, the clock circuit may include the method for calibrating the laser radar as shown above. The clock circuit may be provided on the board 3710, and a plurality of chips, such as a central control chip, may be provided on the board 3710. The board 3710 may be provided in the housing 3720.

[0372] The radar may be a laser radar, a millimeter wave radar, an ultrasonic radar, etc. The radar may be a scanning radar or a non-scanning radar.

[0373] Fig.38 It is a schematic diagram of the structure of an electronic device shown in an embodiment of the present application.

[0374] See also Fig.38 , the electronic device 3800 may include a memory 3810 and a processor 3820. In addition, the electronic device 3800 may also be provided with at least one of a clock generating circuit, a method for clock calibration of a laser radar, or a radar.

[0375] The processor 3820 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0376] The memory 3810 may include various types of storage units, such as system memory, read-only memory (ROM), and permanent storage. Among them, ROM can store static data or instructions required by the processor 3820 or other modules of the computer. The permanent storage device may be a readable and writable storage device. The permanent storage device may be a non-volatile storage device that does not lose the stored instructions and data even after the computer is powered off. In some embodiments, the permanent storage device uses a large-capacity storage device (such as a magnetic or optical disk, flash memory) as a permanent storage device. In some other embodiments, the permanent storage device may be a removable storage device (such as a floppy disk, optical drive). The system memory may be a readable and writable storage device or a volatile readable and writable storage device, such as a dynamic random access memory. The system memory may store some or all instructions and data required by the processor at run time. In addition, the memory 3810 may include any combination of computer-readable storage media, including various types of semiconductor memory chips (such as DRAM, SRAM, SDRAM, flash memory, programmable read-only memory), and disks and / or optical disks may also be used. In some embodiments, the memory 3810 may include a readable and / or writable removable storage device, such as a laser disc (CD), a read-only digital versatile disc (such as a DVD-ROM, a double-layer DVD-ROM), a read-only Blu-ray disc, an ultra-density optical disc, a flash memory card (such as an SD card, a mini SD card, a Micro-SD card, etc.), a magnetic floppy disk, etc. The computer-readable storage medium does not include carrier waves and transient electronic signals transmitted wirelessly or wired.

[0377] The memory 3810 stores executable codes, which, when processed by the processor 3820 , can enable the processor 3820 to execute part or all of the methods described above.

[0378] In addition, the method according to the present application may also be implemented as a computer program or a computer program product, which includes computer program code instructions for executing some or all of the steps in the above method of the present application.

[0379] Alternatively, the present application can also be implemented as a computer-readable storage medium (or non-transitory machine-readable storage medium or machine-readable storage medium) on which executable code (or computer program or computer instruction code) is stored. When the executable code (or computer program or computer instruction code) is executed by a processor of an electronic device (or server, etc.), the processor executes part or all of the steps of the above-mentioned method according to the present application.

[0380] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for calibrating a laser radar, characterized in that: The laser radar includes at least one light signal collection pixel array and at least one laser array, each light signal collection array includes a plurality of pixels arranged in an array, each laser array includes M×N scanning blocks, and the method includes: For each scanning block, a row of pixels in at least one of the optical signal acquisition pixel arrays receives the optical signal from the scanning block within a time period to determine the pixel corresponding to the peak value of the optical signal intensity, and determine the measurement distance and echo area of ​​the row of pixels; Repeat the following operations until the distance compensation value and the echo area corresponding to each reflection area are obtained: move the movable plate so that the plurality of reflection areas are respectively aligned with the laser radar at different time periods; wherein the distance compensation value is the difference between the measured distance and the preset distance; Switch the scanning blocks and repeat the above operation until the distance compensation value and echo area corresponding to each scanning block at different reflectivity are obtained.

2. The method according to claim 1, characterized in that The calibration platform for calibrating the laser radar includes: a movable plate at a preset distance from the laser radar, the movable plate including multiple reflective areas, at least some of the reflective areas have different reflectivities, the plane of the movable plate is perpendicular to the emission light of the laser radar, and can be moved in a perpendicular direction relative to the laser radar.

3. The method according to claim 1, characterized in that After obtaining the distance compensation value and the echo area corresponding to each scanning block at different reflectivities, the method further includes: The distance compensation value corresponding to the uncalibrated echo area is obtained by interpolation calculation.

4. The method according to claim 1 or 3, characterized in that: After obtaining the distance compensation value and the echo area, the method further includes: The scanning block number, the echo area and the distance compensation value of the scanning block are stored in a specific storage space in association with each other.

5. The method according to claim 4, characterized in that The storing the scanning block number, the echo area and the distance compensation value of the scanning block in a specific storage space in association with each other includes: The distance compensation value is stored in a storage space of a scanning block corresponding to the scanning block number, wherein the storage space uses the echo area as an index value and uses the distance compensation value as storage information.

6. The method according to claim 5, characterized in that The storage spaces of the scanning blocks with adjacent scanning block numbers are adjacent, and the number of index values ​​of the storage spaces of all scanning blocks is equal to the number of pixels of the light signal acquisition pixel array.

7. The method according to claim 4, characterized in that One storage address in the storage space stores two distance compensation value pairs corresponding to the echo area, wherein the distance compensation value pair includes a left distance compensation value and a right distance compensation value.

8. The method according to claim 1, characterized in that Before determining the pixel corresponding to the peak value of the light signal intensity and determining the measurement distance and echo area of ​​the row of pixels, the method further includes: Based on a standard light source, receiving and calibrating at least one of the light signal acquisition pixel arrays respectively, to obtain attribute differences of pixels of at least one of the light signal acquisition pixel arrays; The distance determined by the laser radar is compensated based on the attribute difference of the pixels.

9. The method according to claim 1, characterized in that: Also includes: Determine relevant parameters of the distance information output by the laser radar; Decoupling the related parameters to determine a calibration order for the corresponding relationship between some of the related parameters and the distance compensation value; The corresponding relationship between some of the related parameters and the distance compensation value is calibrated according to the calibration sequence.

10. The method according to claim 9, characterized in that The calibrating the correspondence between some of the related parameters and the distance compensation values ​​according to the calibration sequence includes: The laser radar is calibrated in sequence for reception, energy, temperature and absolute distance.

11. A method for improving laser radar ranging accuracy, characterized in that: The laser radar includes at least one light signal collection pixel array and at least one laser array, each light signal collection array includes a plurality of pixels arranged in an array, each laser array includes a plurality of scanning blocks, and the method includes: In response to obtaining the scanning block number and the echo area, determining a storage address in a storage space, wherein the storage space stores a corresponding relationship between the scanning block number, the echo area, and the distance compensation value; acquiring a distance compensation value from the storage space based on the storage address; The distance determined by the laser radar is compensated based on the distance compensation value.

12. The method according to claim 11, characterized in that The step of determining a storage address in a storage space in response to obtaining a scanning block number and an echo area comprises: Get the starting scanning block number, starting pixel number and channel information; Determine a row address, a column address and a scanning block number of a pixel based on the starting scanning block number, the starting pixel number and the channel information; The method further comprises: After compensating the distance determined by the laser radar based on the distance compensation value, the compensated distance is output from a pixel channel, wherein the pixel channel is a channel corresponding to a row address and a column address of the pixel.

13. The method according to claim 11, characterized in that The step of determining a storage address in a storage space in response to obtaining a scanning block number and an echo area comprises: If the obtained echo area successfully matches the echo area in the storage space, a storage address in the storage space is obtained based on the scanning block number and the obtained echo area.

14. The method according to claim 11, characterized in that The step of determining a storage address in a storage space in response to obtaining a scanning block number and an echo area comprises: If the obtained echo area fails to match the echo area in the storage space, the storage addresses of the two echo areas in the storage space that are closest to the obtained echo area are obtained, so as to determine the distance compensation value corresponding to the obtained echo area by interpolation calculation based on the two echo areas closest to the obtained echo area and the two distance compensation values ​​corresponding to the two closest echo areas, wherein the two distance compensation values ​​corresponding to the two closest echo areas are obtained based on the storage addresses of the two echo areas closest to the obtained echo area.

15. The method according to claim 11, characterized in that A storage address in the storage space stores two distance compensation value pairs corresponding to the echo area, wherein the distance compensation value pair includes a left distance compensation value and a right distance compensation value; The step of determining a storage address in a storage space in response to obtaining a scanning block number and an echo area comprises: Get the starting scanning block number, starting pixel number and channel information; Determine a row address and a column address of a pixel based on the starting scanning block number, the starting pixel number and the channel information; Determine a distance compensation value selection direction, and obtain an adjusted echo area, wherein the selection direction includes a left side or a right side, and the adjusted echo area is a multiplication result between the echo area and a preset coefficient; A distance compensation value is obtained from the storage space based on the distance compensation value selection direction and the adjusted echo area.

16. The method according to claim 15, characterized in that The determining the row address and column address of the pixel based on the starting scanning block number, the starting pixel number and the channel information comprises: Determine the row address of the pixel based on the lower 2 bits of the scanning block row counter and the scanning block channel counter; Determine the column address of the pixel based on the upper 2 bits of the scanning block channel counter; The step of determining the distance compensation value and selecting the direction includes: If the value of the 6th bit of the multiplication result is 1, the left side is used as the distance compensation value selection direction, otherwise the right side is used as the distance compensation value selection direction, wherein the multiplication result is 24-bit data including a 7-bit decimal part, and the multiplication result is the multiplication result of the 16-bit echo area and the 8-bit preset coefficient, and the 7-bit decimal part is processed using rounding.

17. A circuit for improving laser radar ranging accuracy, characterized in that: The laser radar includes at least one optical signal acquisition pixel array and at least one laser array, each optical signal acquisition array includes a plurality of pixels arranged in an array, each laser array includes a plurality of scanning blocks, and the circuit includes: A storage address determination circuit, for determining a storage address in a storage space in response to obtaining a scanning block number and an echo area, wherein the storage space stores a corresponding relationship between the scanning block number, the echo area and the distance compensation value; A compensation value acquisition circuit, used for acquiring a distance compensation value from the storage space based on the storage address; A distance compensation circuit is used to compensate the distance determined by the laser radar based on the distance compensation value.

18. A radar, characterized in that: Comprising a circuit for improving laser radar ranging accuracy according to claim 17.

19. An electronic device, characterized in that: include: processor; as well as A memory having executable codes stored thereon, which, when executed by the processor, causes the processor to execute the method according to any one of claims 1 to 16.

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