Diagnostic method for a lidar, lidar and computer storage medium

Abstract

The application provides a diagnostic method for a laser radar, comprising the following steps: S11, emitting a detection pulse; S12, receiving a stray light echo generated by the detection pulse; S13, obtaining a current performance value according to the stray light echo; and S14, diagnosing whether an abnormality occurs in the laser radar according to the current performance value and a reference performance value. The application uses the detection pulse generated by a light emitting device in the laser radar and the stray light echo received by a light receiving device based on the detection pulse to diagnose the emission performance and / or the receiving performance of the laser radar, so that whether the performance of the laser radar is abnormal can be effectively identified, and the problem that the detection capability of the laser radar is reduced due to the performance attenuation or failure of the light emitting device and the light receiving device is solved.

Description

Technical Field

[0001] This invention relates to the field of lidar, and more particularly to a diagnostic method for lidar, a lidar, and a computer storage medium. Background Technology

[0002] LiDAR is a radar system that uses laser beams to detect the position, velocity, and other characteristics of targets. Due to its advantages such as high resolution, good concealment, strong resistance to active interference, excellent detection performance, small size, and light weight, lidar is widely used in fields such as autonomous driving, drones, and intelligent robots.

[0003] During use, lidar systems can experience reduced luminous energy due to aging or hardware failure of the light emitting device. Similarly, aging or hardware failure of the light receiving device can decrease receiving efficiency, thereby reducing the lidar's maximum range and target reflectivity measurement capabilities. Hardware failures, such as those caused by external vibrations or adhesive failure, can lead to broken or misaligned optical components, or damage to the laser and detector, resulting in a degraded or lost lidar function and impacting its detection performance.

[0004] Figure 1 This diagram illustrates a comparison between the optical emitting device of a lidar in its original state and its performance degradation state. The lidar includes an optical emitting device that emits detection pulses under the control of a trigger signal (control signal). The original luminous energy Q in the original state is shown below. Figure 1 As shown in the figure above, under the same control signal and environmental conditions, the performance degradation of the light emitting device will cause a decrease in the emitted energy Q, such as... Figure 1 As shown in the figure below, this reduces the luminous energy of the light-emitting device.

[0005] Figure 2This diagram illustrates a comparison of echo waveforms from a lidar's optical receiver under different levels of performance degradation. The lidar includes an optical transmitter and an optical receiver. The optical transmitter emits a probe pulse under the control of a trigger signal, and the optical receiver receives the echo of the probe pulse on the target. Under the same trigger signal and environmental conditions, the optical transmitter emits a probe pulse, and the optical receiver receives the echo from a target with the same distance and reflectivity. Initially, the echo signal received by the optical receiver has an amplitude of V0. As the performance of the optical receiver gradually degrades during use (assuming no performance degradation of the optical transmitter), the amplitude of the echo signal decreases to V1. Since the amplitude V1 is greater than a threshold, the target can still be identified. However, when the performance of the optical receiver continues to degrade or fails, the amplitude of the echo signal decreases to V2. Since the amplitude V2 is less than the threshold, the lidar can no longer identify the target, i.e., it cannot obtain the target's distance and reflectivity information.

[0006] Therefore, the performance degradation or failure of the light emitting and receiving devices in a lidar will lead to a reduction in the emitted or received energy, resulting in the lidar failing to detect the target or detecting the target but having a large error in the measured distance or reflectivity information.

[0007] The content of the background section only discloses the technology known to the inventors and does not necessarily represent the prior art in this field. Summary of the Invention

[0008] To address the problem of reduced detection capability of lidar due to performance degradation or failure of the optical emitting and receiving devices in existing technologies, this invention relates to a diagnostic method for lidar, comprising:

[0009] S11: Transmit a detection pulse;

[0010] S12: Receive the stray light echo generated by the probe pulse;

[0011] S13: Obtain the current performance value based on the stray light echo;

[0012] S14: Based on the current performance value and the reference performance value, diagnose whether the lidar is malfunctioning.

[0013] According to one aspect of the invention, the current performance value and the reference performance value are obtained under specific conditions, wherein the specific conditions include one or more of ambient temperature, detection field of view, and luminous intensity control.

[0014] According to one aspect of the invention, the stray light echo is an echo pulse within a time window.

[0015] According to one aspect of the invention, the time window includes a fixed time window and a dynamic time window, the fixed time window being related to the size and structure of the lidar, and the dynamic time window being dynamically adjusted based on the reception time of the stray light echo.

[0016] According to one aspect of the invention, the current performance value and / or reference performance value includes one or more of the peak intensity, pulse width, and waveform integral value of the stray light echo.

[0017] According to one aspect of the present invention, step S13 further includes: when the current performance value is within a preset range, repeating steps S11-S12 until multiple sampling results are obtained.

[0018] According to one aspect of the invention, step S13 further includes: obtaining the current performance value based on the average or weighted average of multiple sampling results.

[0019] According to one aspect of the invention, step S14 further includes diagnosing whether the lidar is malfunctioning based on the deviation between the current performance value and the reference performance value.

[0020] According to one aspect of the present invention, the lidar includes a light emitting device and a light receiving device, wherein step S14 further includes: diagnosing whether the luminous intensity of the light emitting device is abnormal and / or whether the detection efficiency of the light receiving device is abnormal based on the current performance value and a reference performance value.

[0021] According to one aspect of the present invention, the lidar includes a plurality of detection channels, each detection channel including at least one laser and at least one detector, wherein step S14 further includes: when the deviation between the current performance value of the detection channel and the reference performance value is greater than a first threshold, correcting the detection result of the detection channel.

[0022] According to one aspect of the invention, step S14 further includes: correcting the distance and / or reflection information of the target detected by the detection channel based on the deviation between the current performance value and the reference performance value.

[0023] According to one aspect of the present invention, step S14 further includes: determining the number of detection channels where the deviation between the current performance value and the reference performance value is greater than a first threshold, and reporting fault information when the number of detection channels is greater than the threshold.

[0024] The present invention also relates to a computer storage medium including computer executable instructions stored thereon, which, when executed by a processor, implement the diagnostic method described above.

[0025] The present invention also relates to a lidar, comprising:

[0026] The optical emitting device includes multiple lasers configured to emit detection pulses individually;

[0027] An optical receiving device includes multiple detectors configured to receive stray light echoes generated by the probe pulses, respectively; and

[0028] A processing device, coupled to the optical emitting device and the optical receiving device, and configured as follows:

[0029] The current performance value is obtained based on the stray light echo;

[0030] Based on the current performance value and the reference performance value, diagnose whether the lidar is malfunctioning.

[0031] According to one aspect of the invention, the light receiving device is further configured to acquire the current performance value and the reference performance value under specific conditions, the specific conditions including one or more of ambient temperature, detection field of view, and luminous intensity control quantity.

[0032] According to one aspect of the invention, the stray light echo is an echo pulse within a time window.

[0033] According to one aspect of the invention, the time window includes a fixed time window and a dynamic time window, the fixed time window being related to the size and structure of the lidar, and the dynamic time window being dynamically adjusted based on the reception time of the stray light echo.

[0034] According to one aspect of the invention, the current performance value includes one or more of the peak intensity of the stray light echo, the pulse width, and the waveform integral value.

[0035] According to one aspect of the present invention, the processing device is further configured to: acquire multiple sampling results when the current performance value is within a preset range.

[0036] According to one aspect of the invention, the processing apparatus is further configured to: obtain the current performance value based on the average or weighted average of multiple sampling results.

[0037] According to one aspect of the invention, the processing device is further configured to diagnose whether the lidar is malfunctioning based on the deviation between the current performance value and the reference performance value.

[0038] According to one aspect of the invention, the processing apparatus is further configured to: diagnose whether the luminous intensity of the light emitting device is abnormal and / or whether the detection efficiency of the light receiving device is abnormal, based on the current performance value and the reference performance value.

[0039] According to one aspect of the invention, the processing apparatus is further configured to: determine a detection channel whose deviation from a current performance value to a reference performance value is greater than a first threshold, and correct the detection results of the corresponding detection channel, wherein each detection channel includes at least one laser and at least one detector.

[0040] According to one aspect of the invention, the processing device is further configured to: correct the detection result of the detection channel when the deviation between the current performance value of the detection channel and the reference performance value is greater than a first threshold.

[0041] According to one aspect of the invention, the processing device is further configured to: determine the number of detection channels in which the deviation between the current performance value and the reference performance value is greater than a first threshold, and report fault information when the number of detection channels is greater than the first threshold.

[0042] This invention utilizes the detection pulses generated by the optical transmitter and the stray light echoes generated by the optical receiver in a lidar to diagnose the lidar's transmission and / or reception performance. The echo beam includes both the detection echo and the stray light echo. When the performance of the optical transmitter and / or the optical receiver degrades or fails, the waveform change of the detection echo shows the same trend as the waveform of the stray light echo inside the lidar. Therefore, the waveform change of the detection echo can be determined based on the waveform change of the stray light echo, thereby effectively identifying whether the lidar has experienced performance abnormalities. This solves the problem of reduced lidar detection capability caused by performance degradation or failure of the optical transmitter and optical receiver. Attached Figure Description

[0043] The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute an undue limitation of this disclosure. In the drawings:

[0044] Figure 1 A schematic diagram comparing the light emitting device of a lidar in its original state and its performance degradation state is shown.

[0045] Figure 2 A schematic diagram showing the echo waveforms of the optical receiving device of a lidar at different levels of performance degradation is presented.

[0046] Figure 3 A schematic diagram of a lidar system employing a coaxial transceiver system is shown.

[0047] Figure 4 A schematic diagram of another type of lidar employing a coaxial transceiver system is shown.

[0048] Figure 5A flowchart of a diagnostic method for lidar according to an embodiment of the present invention is shown;

[0049] Figure 6 A schematic diagram of a lidar according to an embodiment of the present invention is shown;

[0050] Figure 7 A schematic diagram showing the comparison between stray light echo and probe echo pulse is shown;

[0051] Figure 8 This diagram illustrates the time window of stray light echo relative to the transmitter trigger signal.

[0052] Figure 9 A schematic diagram showing the waveform change of stray light echo relative to the transmitter trigger signal is shown;

[0053] Figure 10 A flowchart of a diagnostic method for lidar according to another embodiment of the present invention is shown;

[0054] Figure 11 A schematic diagram of a diagnostic system according to an embodiment of the present invention is shown;

[0055] Figure 12 A schematic diagram of a lidar module according to an embodiment of the present invention is shown. Detailed Implementation

[0056] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0057] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0058] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0059] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0060] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0061] This invention provides a diagnostic method for lidar, comprising transmitting a probe pulse and receiving stray light echoes generated by the probe pulse; obtaining a current performance value based on the stray light echoes; and diagnosing whether the lidar is malfunctioning based on the current performance value and a reference performance value. This invention utilizes the probe pulses generated by the optical transmitter and the stray light echoes received by the optical receiver in the lidar to diagnose the lidar's transmission and / or reception performance. This effectively identifies whether the lidar is experiencing performance abnormalities, thus solving the problem of reduced lidar detection capability caused by performance degradation or failure of the optical transmitter and receiver.

[0062] This method is applicable to optical systems that use coaxial transceivers. Figure 3A schematic diagram of a lidar system employing a coaxial transceiver system is shown. The lidar includes an optical transmitter and an optical receiver. The detection beam L emitted by the optical transmitter passes through a collimating component and a beam splitter, and is finally reflected by a scanning component to the outside of the lidar. The echo L' reflected by the target passes through the scanning component, beam splitter, and convergence component before being received by the optical receiver. By emitting a detection beam and receiving the echo beam reflected by an object, the lidar can detect the distance and reflectivity of targets in the environment. However, as the lifespan of the optical transmitter and receiver changes, their performance will also degrade. For the lidar's transmission and reception performance, this is mainly manifested in a decrease in the emission power of the optical transmitter and the echo reception efficiency of the optical receiver, which will reduce the maximum range and reflectivity measurement capability of the lidar system.

[0063] The stray light generated by the detection beam L emitted by the optical emitting device inside the radar system is also received by the optical receiving device, thus forming a stray light echo. Figure 4 This diagram illustrates another type of lidar employing a coaxial transceiver system. The detection beam L emitted by the optical transmitter passes through a beam splitter and a scanning component (not shown) before exiting. Its echo L' passes through the scanning component and the beam splitter and is received by the optical receiver. Ideally, the beam splitter would ensure that the detection pulse L is incident on the scanning component without changing direction. However, in practice, a small portion of the detection pulse L is reflected by the edge of the beam splitter or other lens assemblies (not shown) and received by the optical receiver, thus forming stray light echoes. It is evident that both stray light echoes and echoes L' are received by the optical receiving device. After the performance of the optical emitting device and / or the optical receiving device degrades, the waveform of the echo L' corresponding to the probe beam L also shows the same trend as the waveform of the stray light inside the lidar. Therefore, this invention utilizes the probe pulse generated by the optical emitting device in the lidar and the optical receiving device to receive the stray light echoes generated based on the probe pulse to diagnose the emission and / or reception performance of the lidar. No additional optical emitting or receiving devices are required, the structure is simple, and it can effectively identify the problem of unexpected changes in the performance boundary of the lidar (e.g., the maximum detection distance is 200 meters when the reflectivity is 10%).

[0064] Unexpected changes include, but are not limited to, the following: the lidar cannot detect an object at a specified reflectivity and distance; or it detects an object, but the reflectivity is lower than expected; or it detects an object, but the reflectivity is higher than expected. Factors leading to unexpected changes include: performance degradation of the optical emitting or receiving device, such as laser aging (attenuation) leading to reduced luminous energy or detector aging (attenuation) leading to reduced echo reception efficiency; or hardware failure in the optical emitting or receiving device causing detection results to be lower or higher than expected.

[0065] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0066] Figure 5 A flowchart of a diagnostic method for lidar according to an embodiment of the present invention is shown. The diagnostic method 10 includes steps S11-S14, as follows:

[0067] In step S11, a probe pulse is emitted.

[0068] Figure 6 A schematic diagram of a lidar according to an embodiment of the present invention is shown. The lidar 20 includes a light emitting device 21 and a light receiving device 22. The light emitting device 21 emits a detection pulse, which passes through other components, such as a lens assembly, and then exits to the outside of the lidar 20.

[0069] In step S12, stray light echoes generated by the probe pulse are received.

[0070] Continue to refer to Figure 6 The laser radar 20 emits a detection pulse from its light-emitting device 21, and the detection echo pulse reflected by the target is received by the light-receiving device 22. Simultaneously, stray light generated within the radar system by this detection pulse is also received by the light-receiving device 22 of the laser radar 20, thus forming a stray light echo. A small portion of the detection pulse is reflected by the edge of the optical element and then received by the light-receiving device 22, forming stray light; another small portion is reflected by the photomask of the laser radar 20 and then received by the light-receiving device 22, forming a stray light echo. There are also various other causes of stray light, which will not be elaborated here. However, those skilled in the art will understand that the stray light echo referred to herein includes echoes generated by reflection, as well as stray light generated by optical crosstalk, etc., and does not constitute a limitation on the technical solution or the technical problem solved by this invention.

[0071] The energy of this stray light echo is usually high, making it indistinguishable from the detection echo pulse, resulting in a near-range detection blind zone for the lidar system. However, when the target is outside the near-range blind zone of the lidar 20, such as... Figure 7 As shown, after receiving the stray light echo, the optical receiver 22 may also receive the detection echo pulse formed by the reflection of the detection pulse by the target. Since the formation time of the stray light echo is fixed when the internal structure of the radar system is fixed, the stray light echo can be filtered out from the multiple detection echo pulses generated by the detection pulse by receiving them.

[0072] According to a preferred embodiment of the present invention, the stray light echo is an echo pulse within a time window. Figure 8A schematic diagram of the time window of stray light echo relative to the trigger signal of the optical transmitter is shown. The stray light echo is generated immediately after the emission time of the optical transmitter 21. That is, after the trigger signal of the optical transmitter 21 is generated, the optical transmitter 21 emits a detection pulse. Part of it is emitted normally to the outside of the lidar 20, and the other part forms a stray light echo within the time window Δt after the trigger signal is generated, which is finally received by the optical receiver 22.

[0073] According to a preferred embodiment of the present invention, the time window Δt includes a fixed time window and a dynamic time window. The fixed time window is related to the size and structure of the lidar 20, while the dynamic time window is dynamically adjusted based on the reception time of the stray light echo. The length of the fixed time window containing the stray light echo is determined according to the system characteristics of the lidar 20, and the fixed time window containing the stray light echo differs for different lidar systems. Typically, the fixed time window Δt containing the stray light echo is determined by the geometry and internal structure of the lidar 20, specifically including the optical path length between the light emitting device 21 and the light receiving device 22 in the lidar 20, the construction and position of the optical components, etc., which can be obtained through prior measurements.

[0074] In reality, the stray light echo generated by the probe pulse within the lidar system may have a pulse duration longer than the fixed time window Δt. Therefore, a certain redundancy can be set according to the reception time of the stray light echo, i.e., a dynamic time window can be set. For example, the dynamic time window can be set and adjusted according to the threshold time and peak time of the stray light pulse to obtain a complete stray light echo waveform, which is beneficial for subsequent analysis of waveform information.

[0075] For example, if the radar dome is dirty, the location of stray light echoes will exceed the range of the fixed time window Δt. Based on the system characteristics, the fixed time window for stray light echoes from the lidar is determined to be within 10 ns after the transmission time. Therefore, a dynamic time window of 20-25 ns can be set. That is, any echo pulse received by the optical receiver 22 within 30-35 ns after the transmission time of the detection pulse can be considered as stray light echo.

[0076] In step S13, the current performance value is obtained based on the stray light echo.

[0077] Continue to refer to Figure 6The optical transmitter 21 emits a probe pulse, and the optical receiver 22 receives the probe echo pulse. When the optical transmitter 21 and / or the optical receiver 22 age (attenuate), the waveform of the probe echo pulse will change accordingly, and simultaneously, the waveform of the stray light echo will also change accordingly, with both showing the same trend. The change in the stray light waveform can be used to diagnose the lidar 20. Therefore, in this step, the current performance value of the lidar 20 is first obtained, that is, the characteristic parameters of the stray light echo, such as the signal amplitude.

[0078] According to a preferred embodiment of the present invention, in diagnostic method 10, step S13 further includes: when the current performance value is within a preset range, repeating steps S11-S12 until multiple sampling results are obtained. The reasonableness of the current performance value is judged to avoid the influence of other factors (such as temperature, interference from other laser emission sources). For example, the light emitting device 21 emits a probe pulse of a specified emission intensity to determine whether the characteristic parameters of the stray light echo are within a preset range. If so, a probe pulse is emitted, and the stray light echo generated by the probe pulse is received, repeating this process multiple times to obtain multiple sampling results.

[0079] According to a preferred embodiment of the present invention, in diagnostic method 10, step S13 further includes: obtaining the current performance value based on the average or weighted average of multiple sampling results. Averaging multiple measurements can improve the accuracy of the current performance value. If the current performance value includes multiple characteristic parameters of stray light echoes, weight values ​​can be set for each of these characteristic parameters, and a weighted average can be obtained through multiple measurements, which can also improve the accuracy of the current performance value. For example, when multiple characteristic parameters are used in combination, a method of setting confidence levels can be adopted, such as setting the confidence level of characteristic parameter A to 50%, the confidence level of characteristic parameter B to 30%, and the confidence level of characteristic parameter C to 20%, and then calculating the current performance value.

[0080] In step S14, based on the current performance value and the reference performance value, it is determined whether the lidar is malfunctioning.

[0081] Figure 9 The diagram illustrates the waveform change of stray light echo relative to the transmitter trigger signal, combined with... Figure 6After a trigger signal, the optical transmitter 21 emits a probe pulse, and the optical receiver 22 receives the stray light echo within a time window t2-t1. Before the optical transmitter 21 and / or the optical receiver attenuate, the stray light waveform is V0; after the optical transmitter 21 and / or the optical receiver 22 attenuate, the stray light waveform is V1. Under the same control quantity trigger signal and the same environmental conditions, the characteristic that the stray light waveform changes as the optical transmitter 21 and / or the optical receiver 22 gradually ages during use is used to diagnose whether the lidar 20 is malfunctioning. That is, the lidar 20 is diagnosed based on the current performance value and the reference performance value of the stray light echo.

[0082] According to a preferred embodiment of the invention, the diagnostic method 10 further includes: acquiring a current performance value and a reference performance value under the same specific conditions, wherein the specific conditions include one or more of ambient temperature, detection field of view, and luminous intensity control quantity. For example, before the lidar 20 is taken offline, the characteristic parameters of the stray light echo received by the light receiving device 22 are used as the reference performance value of the lidar 20 under the specified temperature range, detection field of view, and luminous intensity control quantity (e.g., the driving voltage of the laser) determined through calibration. In practical applications, under the same specific conditions, i.e., the specified temperature range, detection field of view, and luminous intensity control quantity, the characteristic parameters of the stray light echo received by the light receiving device 22 are used as the current performance value. Thus, the current measured value and the reference value of the performance value have a basis for comparison. One or more specific conditions can be set as needed, wherein the ambient temperature is acquired by a temperature sensor, the detection field of view is obtained by the internal configuration information of the lidar 20, the luminous intensity control quantity is acquired by the luminous state of the detection channel, or, when executing the diagnostic method 10, the laser is triggered to emit light at a specified luminous intensity within a specified time window.

[0083] According to a preferred embodiment of the invention, the current performance value and / or reference performance value includes one or more of the peak intensity, pulse width, and waveform integral value of the stray light echo. Reference Figure 9 The characteristic parameters of stray light echoes include peak intensity H1, pulse width W1, and waveform integral value E1. The waveform integral value is the integral of the digital quantity of the stray light echo inside the radar, measured by the analog-to-digital converter; that is, the waveform area of ​​the stray light echo. (Continue to refer to...) Figure 9The stray light waveform before attenuation of the optical transmitter 21 and / or optical receiver 22 is V0, and its characteristic parameters are used as reference performance values; the stray light waveform after attenuation of the optical transmitter 21 and / or optical receiver 22 is V1, and its characteristic parameters are used as current performance values. Thus, the current measured value and the reference value of the performance value have the same comparison parameters, for example, to diagnose the transceiver performance or transceiver efficiency of the lidar 20, thereby determining whether the lidar 20 has malfunctioned.

[0084] This invention provides a diagnostic method for a lidar 20. This diagnostic method is applicable to coaxial transceiver optical systems. It utilizes the detection pulses generated by the optical emitting device 21 and the stray light echoes generated by the optical receiving device 22 based on the detection pulses to diagnose the emission and / or reception performance of the lidar 20. This effectively identifies whether the lidar 20 has experienced performance abnormalities, thereby solving the problem of reduced detection capability of the lidar 20 due to performance degradation or failure of the optical emitting device 21 and the optical receiving device 22.

[0085] According to a preferred embodiment of the present invention, in diagnostic method 10, step S14 further includes: diagnosing whether the lidar 20 is malfunctioning based on the deviation between the current performance value and the reference performance value. (Continue to refer to...) Figure 9 The stray light waveform before attenuation of the optical transmitter 21 and / or optical receiver 22 is V0, which is used as a reference performance value. Under the same specific conditions, the stray light waveform after attenuation of the optical transmitter 21 and / or optical receiver 22 is V1, which is used as the current performance value. The change in the stray light echo waveform is used to measure the performance attenuation of the optical transmitter 21 and / or optical receiver 22, thereby determining whether the lidar 20 has malfunctioned.

[0086] According to a preferred embodiment of the present invention, the lidar 20 includes a light emitting device 21 and a light receiving device 22. In the diagnostic method 10, step S14 further includes: diagnosing whether the luminous intensity of the light emitting device 21 is abnormal and / or whether the detection efficiency of the light receiving device 22 is abnormal based on the current performance value and the reference performance value. For example, after determining that the lidar 20 is abnormal based on the current performance value and the reference performance value, the reasons for the change in the stray light echo waveform are further analyzed based on the performance attenuation curve of the light emitting device 21 and the performance attenuation curve of the light receiving device 22.

[0087] According to a preferred embodiment of the present invention, the lidar 20 includes multiple detection channels. In the diagnostic method 10, step S14 further includes: when the deviation between the current performance value and the reference performance value of the detection channel is greater than a first threshold, correcting the detection result of the detection channel. For example, under specific conditions, the diagnostic method 10 sequentially measures multiple detection channels, identifies whether the performance of the detection channel has degraded based on the current performance value and the reference performance value, and calculates and determines the amount of performance degradation. When the amount of performance degradation is greater than the first threshold, the detection result of the channel is corrected to compensate for the measurement error caused by the attenuation of the light emitting device 21 and / or the light receiving device.

[0088] According to a preferred embodiment of the present invention, in diagnostic method 10, step S14 further includes: correcting the reflectivity of the detection channel based on the deviation between the current performance value and the reference performance value. For example, based on the current performance value and the reference performance value, it is identified whether the performance of the detection channel has degraded, and the amount of performance degradation is calculated and determined. When the amount of performance degradation is greater than a first threshold, the reflectivity of the target measured for that channel is corrected to compensate for the measurement error caused by the attenuation of the light emitting device 21 and / or the light receiving device 22.

[0089] According to a preferred embodiment of the present invention, in the diagnostic method 10, step S14 further includes: determining the number of detection channels whose deviation between the current performance value and the reference performance value is greater than a first threshold; and reporting fault information when the number of detection channels is greater than the threshold. For example, under specific conditions, the diagnostic method 10 sequentially measures multiple detection channels, identifies whether the performance of the detection channel has degraded based on the current performance value and the reference performance value, and calculates and determines the amount of performance degradation. The number of detection channels whose performance degradation is greater than the first threshold is counted; for example, if the performance degradation of one detection channel is greater than the first threshold, fault information is reported.

[0090] According to a preferred embodiment of the present invention, in the diagnostic method 10, step S14 further includes: diagnosing whether the lidar has malfunctioned based on whether the deviation between the current performance value and the reference performance value is within the allowable error range. For example, by setting the allowable error range according to the tolerance of the radar system to performance degradation, it is determined whether the deviation between the current performance value and the reference performance value is within the allowable error range, thereby diagnosing whether the lidar 20 has malfunctioned.

[0091] Figure 10A flowchart of a diagnostic method for lidar according to another embodiment of the present invention is shown. By utilizing the probe pulses generated by the optical transmitter and the stray light echoes generated based on the probe pulses received by the optical receiver in the lidar, the transmission and / or reception performance of the lidar can be diagnosed. This effectively identifies whether the lidar has experienced performance abnormalities, thus solving the problem of reduced lidar detection capability caused by performance degradation or failure of the optical transmitter and receiver. The diagnostic method is as follows:

[0092] In step S1: Obtain the reference performance value.

[0093] Before the lidar 20 is taken offline, the performance values ​​of the lidar are measured under specified ambient temperature range, detection field of view, and light intensity control conditions of the light emitting device 21, and are used as reference performance values. For example, the waveform integral value of the stray light echo of each detection channel received by the light receiving device 22 is used as the reference performance value of the lidar 20 before aging.

[0094] Step S2: Under specific conditions, obtain the current performance value;

[0095] The specific conditions include one or more of the following: ambient temperature, detection field of view, and luminous intensity control parameters. Under the same specific conditions as those used to obtain the reference performance value, the current performance value is obtained. The reference performance value and the current performance value include one or more of the following: peak intensity of stray light echo, pulse width, and waveform integral value.

[0096] In step S3: Determine whether the current performance value is within the preset range;

[0097] The current performance values ​​of each detection channel are judged to ensure reasonableness, avoiding the influence of other factors (such as temperature, interference from other lasers). The reasonableness judgment specifically includes whether the current performance value is within the preset range. For example, under the light intensity of the specified light emitting device 21, whether the waveform integral value of the stray light echo is within the preset range.

[0098] In step S4: Determine whether multiple samplings have been completed. If multiple samplings have been completed, proceed to step S5; otherwise, repeat step S2. The number of samplings can be preset and adjusted.

[0099] Step S5: Determine whether the average or weighted average of the current performance values ​​from multiple samples is outside the allowable error range;

[0100] The average or weighted average of the current performance values ​​from multiple samples is taken to improve the accuracy of numerical judgment. Then, it is determined whether the average or weighted average of the current performance values ​​is less than the difference between the reference performance value and the deviation (i.e., outside the allowable error range). For example, if the waveform integral value of the stray light echo is used as the current performance value, it is determined whether the waveform integral value of the stray light echo is less than the difference between the waveform integral value and the deviation in the reference performance value. If so, step S6 is executed; otherwise, step S8 is executed.

[0101] In step S6: Determine if the number of anomalies exceeds a threshold. If the number of anomalies exceeds the threshold (e.g., 1 time), proceed to step S7, which determines that a fault exists and reports the fault. Otherwise, re-execute step S2. The number of anomalies refers to the number of times the difference between the reference performance value and the deviation occurs in multiple samplings, or the number of detection channels whose values ​​are less than the difference between the reference performance value and the deviation. The threshold can be adjusted.

[0102] In step S8: If no abnormality is found, a fault-free report can be submitted.

[0103] In summary, the diagnostic method 10 has been introduced through steps S11-S14 and further described through embodiments. It can be seen that the technical solution of the present invention utilizes the detection pulse generated by the optical emitting device and the stray light echo generated based on the detection pulse in the laser radar to diagnose the laser radar's emission and / or reception performance. The echo pulse includes a detection echo pulse and a stray light pulse. When the optical emitting device and / or the optical receiving device ages, the waveform change of the detection echo pulse has the same trend as the waveform of the stray light echo inside the laser radar. Therefore, without the need for additional light sources and optical receiving devices, the waveform change of the stray light echo can effectively identify whether the laser radar has experienced performance abnormalities, thus solving the problem of reduced laser radar detection capability caused by the performance degradation or failure of the optical emitting device and / or the optical receiving device.

[0104] The present invention also relates to a computer storage medium including computer executable instructions stored thereon, which, when executed by a processor, implement the diagnostic method 10 as described above.

[0105] The present invention also relates to a diagnostic system 30, see reference. Figure 11The diagnostic system 30 includes an optical transmitter 31, an optical receiver 32, a processing unit 33, and a storage unit 34. The optical transmitter 31 is configured to emit a probe pulse, the optical receiver 32 is configured to receive stray light echoes generated by the probe pulse, and the processing unit is configured to obtain a current performance value based on the stray light echo, and diagnose whether the optical transmitter 31 and the optical receiver 32 are malfunctioning based on the current performance value and a reference performance value. The storage unit 34 is configured to store the reference performance value. The diagnostic system 30 uses the probe pulse generated by the optical transmitter 31 and the stray light echoes received by the optical receiver 32 based on the probe pulse to diagnose the emission performance of the optical transmitter 31 and / or the reception performance of the optical receiver 32, thereby effectively identifying whether the optical transmitter 31 and / or the optical receiver 32 are malfunctioning and promptly detecting problems with reduced detection capability.

[0106] The present invention also relates to a lidar, see reference Figure 12 The lidar 20 includes:

[0107] The light emitting device 21 includes multiple lasers 211 configured to emit detection pulses respectively;

[0108] The optical receiving device 22 includes a plurality of detectors 221 configured to receive stray light echoes generated by the probe pulses, respectively; and

[0109] Processing device 23, coupled to the light emitting device 21 and the light receiving device 22, and configured as follows:

[0110] The current performance value is obtained based on the stray light echo;

[0111] Based on the current performance value and the reference performance value, diagnose whether the lidar 20 is malfunctioning.

[0112] According to a preferred embodiment of the present invention, the light receiving device 21 is further configured to receive stray light echoes generated by the probe pulse under specific conditions, the specific conditions including one or more of ambient temperature, probe field of view, and luminous intensity control.

[0113] According to a preferred embodiment of the present invention, the stray light echo is an echo pulse within a time window.

[0114] According to a preferred embodiment of the present invention, the time window includes a fixed time window and a dynamic time window, the fixed time window being related to the size and structure of the lidar 20, and the dynamic time window being dynamically adjusted based on the reception time of the stray light echo.

[0115] According to a preferred embodiment of the present invention, the current performance value includes one or more of the peak intensity, pulse width, and waveform integral value of the stray light echo.

[0116] According to a preferred embodiment of the present invention, the processing device 23 is further configured to: acquire multiple sampling results when the current performance value is within a preset range.

[0117] According to a preferred embodiment of the present invention, the processing device 23 is further configured to obtain the current performance value based on the average or weighted average of multiple sampling results.

[0118] According to a preferred embodiment of the present invention, the processing device 23 is further configured to diagnose whether the lidar 20 is malfunctioning based on the deviation between the current performance value and the reference performance value.

[0119] According to a preferred embodiment of the present invention, the processing device 23 is further configured to: diagnose whether the luminous intensity of the light emitting device 21 is abnormal and / or the detection efficiency of the light receiving device 22 is abnormal based on the current performance value and the reference performance value.

[0120] According to a preferred embodiment of the present invention, the processing device 23 is further configured to: determine the detection channel whose deviation between the current performance value and the reference performance value is greater than a first threshold, and correct the detection results of the corresponding detection channel, wherein the plurality of lasers and the plurality of detectors respectively form a plurality of detection channels.

[0121] According to a preferred embodiment of the present invention, the processing device 23 is further configured to: correct the detection result of the detection channel when the deviation between the current performance value and the reference performance value of the detection channel is greater than a first threshold.

[0122] According to a preferred embodiment of the present invention, the processing device 23 is further configured to: determine the number of detection channels whose deviation between the current performance value and the reference performance value is greater than a first threshold, and report fault information when the number of detection channels is greater than the first threshold.

[0123] According to a preferred embodiment of the present invention, the processing device 23 is further configured to: diagnose whether the lidar 20 is malfunctioning based on whether the deviation between the current performance value and the reference performance value is within the allowable error range.

[0124] The light emitting device 21 mentioned above includes, for example, the following lasers: vertical-cavity surface-emitting laser (VCSEL); edge-emitting laser (EEL). The light receiving device 22 mentioned above includes, for example, the following detectors: single-photon avalanche diode (SPAD) detector; avalanche photodiode (APD) detector; silicon photomultiplier (SiPM) detector.

[0125] This invention utilizes the detection pulses generated by the optical transmitter 21 and the stray light echoes generated by the optical receiver 22 in the lidar 20 to diagnose the transmission and / or reception performance of the lidar 20. This effectively identifies whether the lidar 20 has experienced performance abnormalities, thus solving the problem of reduced detection capability of the lidar 20 due to performance degradation or failure of the optical transmitter 21 and the optical receiver 22.

[0126] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A diagnostic method for a laser radar, the laser radar comprising a plurality of detection channels, a detection channel of the plurality of detection channels comprising at least one laser and at least one detector, the diagnostic method comprising: S11: emitting a detection pulse; S12: receiving a stray light echo generated by the detection pulse; S13: obtaining a current performance value according to the stray light echo; S14: diagnosing whether an abnormality occurs in the detection channel according to the current performance value and a reference performance value, determining a number of detection channels in which an abnormality occurs, and diagnosing whether an abnormality occurs in the laser radar; wherein the stray light echo is an echo pulse within a time window, the time window comprising a fixed time window and a dynamic time window, the fixed time window being related to a size and structure of the laser radar, the dynamic time window being dynamically adjusted based on a receiving time of the stray light echo, and the time window being greater than the fixed time window; the diagnostic method further comprising: determining a performance attenuation amount of the detection channel according to a deviation between the current performance value and the reference performance value of the detection channel, and correcting a detection result of the detection channel when the performance attenuation amount is greater than a first threshold, the detection result comprising a distance and / or reflection information of a target; the diagnostic method further comprising: performing a reasonableness judgment on the current performance value of the detection channel to determine whether the current performance value is within a preset range; performing multiple samplings on the current performance value of the detection channel; and diagnosing whether an abnormality occurs in the detection channel according to the current performance values obtained through the multiple samplings.

2. The diagnostic method of claim 1, wherein the current performance value and the reference performance value are respectively obtained under specific conditions, the specific conditions comprising one or more of an ambient temperature, a detection field of view, and a light emission intensity control amount.

3. The diagnostic method of claim 1, wherein the current performance value and / or the reference performance value comprises one or more of a peak intensity, a pulse width, and a waveform integral value of the stray light echo; when the current performance value is within a preset range, repeating steps S11-S12 until a plurality of sampling results are obtained; obtaining the current performance value based on an average value or a weighted average value of the plurality of sampling results; diagnosing whether an abnormality occurs in the laser radar based on a deviation between the current performance value and the reference performance value; diagnosing whether an abnormality occurs in a light emission intensity of the light emitting device and / or whether an abnormality occurs in a detection efficiency of the light receiving device according to the current performance value and the reference performance value; and determining a number of detection channels in which a deviation between the current performance value and the reference performance value is greater than a first threshold, and reporting fault information when the number of detection channels is greater than a threshold.

9. A computer storage medium comprising computer executable instructions stored thereon, the executable instructions implementing the diagnostic method of any one of claims 1-8 when executed by a processor.

10. A laser radar comprising: a light emitting device comprising a plurality of lasers configured to respectively emit a detection pulse; ​ ​ ​ ​ ​ ​ ​ ​ 4. The diagnostic method according to claim 1, wherein said step S13 further comprises: ​ 5. The diagnostic method according to claim 4, wherein said step S13 further comprises: ​ 6. The diagnostic method according to any one of claims 1-5, wherein said step S14 further comprises: ​ 7. The diagnostic method according to any one of claims 1-5, the lidar comprising a light emitting device and a light receiving device, wherein the step S14 further comprises: ​ 8. The diagnostic method according to claim 1, wherein said step S14 further comprises: ​ ​ ​ ​ The light receiving device comprises a plurality of detectors configured to respectively receive stray light echoes generated by the detection pulses; And The processing device is coupled with the light emitting device and the light receiving device, and is configured to: obtain a current performance value according to the stray light echoes; diagnose whether an abnormality occurs in a detection channel according to the current performance value and a reference performance value, determine the number of detection channels in which the abnormality occurs, and diagnose whether an abnormality occurs in the laser radar, wherein the laser radar has a plurality of detection channels, and a detection channel in the plurality of detection channels comprises at least one laser and at least one detector; wherein the stray light echoes are echo pulses within a time window, the time window comprises a fixed time window and a dynamic time window, the fixed time window is related to the size and structure of the laser radar, and the dynamic time window is dynamically adjusted based on the receiving time of the stray light echoes; and the time window is greater than the fixed time window; The processing device is further configured to: determine a performance attenuation amount of the detection channel according to the deviation between the current performance value and the reference performance value of the detection channel, and correct a detection result of the detection channel when the performance attenuation amount is greater than a first threshold, the detection result comprising the distance and / or reflection information of a target; The processing device is further configured to: perform a reasonableness judgment on the current performance value of the detection channel to determine whether the current performance value is within a preset range; perform multiple sampling on the current performance value of the detection channel; and diagnose whether an abnormality occurs in the detection channel according to the current performance values obtained through multiple sampling.

11. The laser radar of claim 10, wherein the light receiving device is further configured to respectively obtain the current performance value and the reference performance value under specific conditions, the specific conditions comprising one or more of an ambient temperature, a detection field of view, and a light emission intensity control amount.

12. The laser radar of claim 10, wherein the current performance value comprises one or more of a peak intensity, a pulse width, and a waveform integral value of the stray light echoes.

13. The laser radar of claim 10, wherein the processing device is further configured to obtain a multiple sampling result when the current performance value is within a preset range.

14. The laser radar of claim 13, wherein the processing device is further configured to obtain the current performance value based on an average value or a weighted average value of the multiple sampling results.

15. The laser radar of any one of claims 10-14, wherein the processing device is further configured to diagnose whether an abnormality occurs in the laser radar based on the deviation between the current performance value and the reference performance value.

16. The laser radar of any one of claims 10-14, wherein the processing device is further configured to diagnose whether an abnormality occurs in a light emission intensity of the light emitting device and / or whether an abnormality occurs in a detection efficiency of the light receiving device according to the current performance value and the reference performance value. 17.The lidar of claim 10, wherein the processing device is further configured to determine a number of detection channels whose deviation of current performance value from reference performance value is greater than a first threshold, and report a fault message when the number of detection channels is greater than the first threshold.

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