CN114488095A - Diagnosis method for laser radar, laser radar and computer storage medium - Google Patents
Diagnosis method for laser radar, laser radar and computer storage medium Download PDFInfo
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- CN114488095A CN114488095A CN202111596456.5A CN202111596456A CN114488095A CN 114488095 A CN114488095 A CN 114488095A CN 202111596456 A CN202111596456 A CN 202111596456A CN 114488095 A CN114488095 A CN 114488095A
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
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Abstract
The invention provides a diagnosis method for a laser radar, which comprises the following steps: s11: emitting a probe pulse; s12: receiving stray light echo generated by the detection pulse; s13: acquiring a current performance value according to the stray light echo; s14: and diagnosing whether the laser radar is abnormal or not according to the current performance value and the reference performance value. The invention diagnoses the transmitting performance and/or receiving performance of the laser radar by using the detection pulse generated by the light transmitting device in the laser radar and the stray light echo generated by the light receiving device based on the detection pulse, and can effectively identify whether the performance of the laser radar is abnormal or not so as to solve the problem that the detection capability of the laser radar is reduced due to the performance attenuation or failure of the light transmitting device and the light receiving device.
Description
Technical Field
The present invention relates to the field of laser radars, and in particular, to a diagnosis method for a laser radar, and a computer storage medium.
Background
The laser radar is a radar system that detects a characteristic amount such as a position and a velocity of a target by emitting a laser beam. Laser radar is widely applied to the fields of automatic driving, unmanned aerial vehicles, intelligent robots and the like due to the advantages of high resolution, good concealment, strong active interference resistance, good detection performance, small size, light weight and the like.
In the use process of the laser radar, the light emitting energy is reduced due to the aging of a light emitting device or the failure of hardware, and the receiving efficiency is reduced due to the aging of a light receiving device or the failure of hardware, so that the maximum remote measurement capability and the target reflectivity capability of the laser radar are reduced. The hardware failure, for example, due to external vibration, failure of fixing glue, etc., causes the optical device to be cracked or dislocated, or the laser and the detector to be damaged, etc., so that the function of the laser radar is degraded or lost, and the detection performance of the laser radar is affected.
Fig. 1 shows a schematic diagram comparing an original state and a performance attenuation state of a light emitting device of a laser radar, the laser radar includes the light emitting device, the light emitting device emits a detection pulse under the control of a trigger signal (control signal), original luminous energy Q in the original state is shown in an upper graph of fig. 1, under the same control amount of the trigger signal and the same environmental condition, the performance attenuation of the light emitting device can make the luminous energy Q generate attenuation, as shown in a lower graph of fig. 1, thereby the luminous energy of the light emitting device is reduced.
Fig. 2 is a schematic diagram showing comparison of echo waveforms of a light receiving device of a laser radar in different performance attenuation states, wherein the laser radar comprises a light emitting device and a light receiving device, the light emitting device emits a detection pulse under the control of a trigger signal, and the light receiving device receives an echo of the detection pulse on a target. Under the trigger signal with the same control quantity and the same environmental condition, the light emitting device emits a probe pulse, and the light receiving device receives the echo of the target with the same distance and reflectivity of the probe pulse, wherein the amplitude of the echo signal received by the light receiving device in the original state is V0, and as the performance of the light receiving device gradually attenuates in the use process (assuming that the performance of the light emitting device does not attenuate), the amplitude of the echo signal after the performance attenuation is reduced to V1, and the amplitude of the echo signal V1 is greater than a threshold value, and the target can be identified, but when the performance of the light receiving device continues to attenuate or fails, the amplitude of the echo signal is reduced to V2, and the amplitude of the echo signal V2 is less than the threshold value, so that the laser radar cannot identify the target, that is, and cannot acquire the distance and reflectivity information of the target.
Therefore, the performance attenuation or failure of the light emitting device and the light receiving device in the laser radar can cause the reduction of the light emitting energy or the reduction of the receiving energy, and further, the laser radar can not detect the target or can detect the target but has larger error of the measured distance or reflectivity information.
The statements in this background section merely disclose technology known to the inventors and do not, of course, represent prior art in the art.
Disclosure of Invention
Aiming at the problem that the detection capability of a laser radar is reduced due to the performance attenuation or failure of a light emitting device and a light receiving device in the prior art, the invention relates to a diagnosis method for the laser radar, which comprises the following steps:
s11: emitting a probe pulse;
s12: receiving stray light echo generated by the detection pulse;
s13: acquiring a current performance value according to the stray light echo;
s14: and diagnosing whether the laser radar is abnormal or not according to the current performance value and the reference performance value.
According to an aspect of the present invention, wherein the current performance value and the reference performance value are respectively obtained under specific conditions, wherein the specific conditions include one or more of an ambient temperature, a detection field of view, and a luminous intensity control amount.
According to one aspect of the invention, wherein the stray light echo is an echo pulse within a time window.
According to an aspect of the invention, 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 echo.
According to an aspect of the invention, the current and/or reference performance values comprise one or more of a peak intensity, a pulse width, and a waveform integral value of the stray light echo.
According to an aspect of the present invention, wherein the step S13 further includes: and when the current performance value is within the preset range, repeating the steps S11-S12 until a plurality of sampling results are obtained.
According to an aspect of the present invention, wherein the step S13 further includes: and acquiring the current performance value based on the average value or the weighted average value of the multiple sampling results.
According to an aspect of the present invention, wherein the step S14 further includes: diagnosing whether the lidar is abnormal based on a deviation between the current performance value and a reference performance value.
According to an aspect of the present invention, the lidar includes a light emitting device and a light receiving device, wherein the step S14 further includes: and diagnosing whether the light emitting intensity of the light emitting device is abnormal and/or the detection efficiency of the light receiving device is abnormal according to the current performance value and the reference performance value.
According to an aspect of the present invention, the lidar comprises a plurality of detection channels, each detection channel comprising at least one laser and at least one detector, wherein the step S14 further comprises: when the deviation between the current performance value and the reference performance value of the detection channel is larger than a first threshold value, the detection result of the detection channel is corrected.
According to an aspect of the present invention, wherein the step S14 further includes: correcting the distance and/or reflection information of the detection channel for detecting the object based on the deviation between the current performance value and the reference performance value.
According to an aspect of the present invention, wherein the step S14 further includes: and determining the number of the detection channels of which 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 the detection channels is greater than the threshold.
The invention also relates to a computer storage medium comprising computer executable instructions stored thereon which, when executed by a processor, implement a diagnostic method as described above.
The invention also relates to a lidar comprising:
a light emitting device including a plurality of lasers configured to emit probe pulses, respectively;
a light receiving device including a plurality of detectors configured to receive stray light echoes generated by the detection pulses, respectively; and
a processing device coupled with the light emitting device and the light receiving device and configured to:
acquiring a current performance value according to the stray light echo;
and diagnosing whether the laser radar is abnormal or not according to the current performance value and the reference performance value.
According to an aspect of the present invention, wherein the light receiving device is further configured to acquire the current performance value and the reference performance value, respectively, under specific conditions including one or more of an ambient temperature, a detection field of view, and a luminous intensity control amount.
According to one aspect of the invention, wherein the stray light echo is an echo pulse within a time window.
According to an aspect of the invention, 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 echo.
According to one aspect of the invention, the current performance value comprises one or more of a peak intensity, a pulse width, and a waveform integration value of the stray light echo.
According to an aspect of the invention, the processing device is further configured to: and when the current performance value is within a preset range, obtaining a multi-sampling result.
According to an aspect of the invention, the processing device is further configured to: and acquiring the current performance value based on the average value or the weighted average value of the multiple sampling results.
According to an aspect of the invention, the processing device is further configured to: diagnosing whether the lidar is abnormal based on a deviation between the current performance value and a reference performance value.
According to an aspect of the invention, the processing device is further configured to: and diagnosing whether the light emitting intensity of the light emitting device is abnormal and/or the detection efficiency of the light receiving device is abnormal according to the current performance value and the reference performance value.
According to an aspect of the invention, the processing device is further configured to: and determining the detection channels with the deviation of the current performance value and the reference performance value larger than a first threshold value, and correcting the detection result of the corresponding detection channels, wherein each detection channel comprises at least one laser and at least one detector.
According to an aspect of the invention, the processing device is further configured to: when the deviation between the current performance value and the reference performance value of the detection channel is larger than a first threshold value, the detection result of the detection channel is corrected.
According to an aspect of the invention, the processing device is further configured to: and determining the number of the detection channels of which 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 the detection channels is greater than the first threshold.
The invention utilizes the detection pulse generated by the light emitting device in the laser radar and the light receiving device to receive the stray light echo generated based on the detection pulse to diagnose the emitting performance and/or the receiving performance of the laser radar, wherein the echo light beam comprises the detection echo and the stray light echo.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to limit the disclosure. In the drawings:
FIG. 1 is a schematic diagram showing a comparison of a light emitting device of a lidar in a raw state and a performance degradation state;
FIG. 2 is a diagram showing the comparison of echo waveforms of the light receiving device of the laser radar in different performance attenuation states;
FIG. 3 shows a schematic diagram of a lidar employing a coaxial transceiver system;
FIG. 4 shows a schematic diagram of another lidar employing a coaxial transceiver system
FIG. 5 shows a flow diagram of a diagnostic method for lidar in accordance with one embodiment of the invention;
FIG. 6 shows a lidar schematic diagram of one embodiment of the invention;
FIG. 7 shows a schematic diagram of stray light echo versus probe echo pulse;
FIG. 8 shows a time window schematic of a stray light echo with respect to an emitter trigger signal;
FIG. 9 is a diagram showing the waveform change of the stray light echo relative to the trigger signal of the transmitting end;
FIG. 10 shows a flow diagram of a diagnostic method for lidar in accordance with another embodiment of the invention;
FIG. 11 shows a diagnostic system schematic of one embodiment of the present invention;
FIG. 12 shows a block schematic diagram of a lidar in accordance with one embodiment of the invention.
Detailed Description
In the following, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection, either mechanically, electrically, or in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly above and obliquely above the second feature, or simply meaning that the first feature is at a lesser level than the second feature.
The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.
The invention provides a diagnosis method for a laser radar, which comprises the steps of transmitting a detection pulse and receiving a stray light echo generated by the detection pulse, and acquiring a current performance value according to the stray light echo; and diagnosing whether the laser radar is abnormal or not according to the current performance value and the reference performance value. The invention diagnoses the transmitting performance and/or receiving performance of the laser radar by using the detection pulse generated by the light transmitting device in the laser radar and the stray light echo generated by the light receiving device based on the detection pulse, and can effectively identify whether the performance of the laser radar is abnormal or not so as to solve the problem that the detection capability of the laser radar is reduced due to the performance attenuation or failure of the light transmitting device and the light receiving device.
The method is applicable to an optical system adopting coaxial transceiving, and fig. 3 shows a schematic diagram of a laser radar adopting the coaxial transceiving system, wherein the laser radar comprises a light emitting device and a light receiving device, a detection light beam L emitted by the light emitting device passes through a collimating component and a light splitting component, the detection light beam L is finally reflected to the outside of the laser radar by a scanning component, and an echo L' reflected by a target is received by the light receiving device after passing through the scanning component, the light splitting component and a converging component. By emitting the detection light beam and receiving the echo light beam reflected by the object, the laser radar can detect the target distance and the reflectivity in the environment, but the performance can be attenuated along with the change of the service life of the light emitting device and the light receiving device, and for the emission performance and the receiving performance of the laser radar, the emission power of the light emitting device and the echo receiving efficiency of the light receiving device are reduced, so that the maximum distance measuring capability and the reflectivity measuring capability of the radar system are reduced.
Stray light generated by the probe light beam L emitted by the light emitting device in the radar system is also received by the light receiving device, so that a stray light echo is formed. Fig. 4 shows a schematic diagram of another lidar employing a coaxial transceiver system, in which a probe beam L emitted from a light emitting device is emitted through a beam splitter and a scanning unit (not shown), and an echo L' is received by a light receiving device after passing through the scanning unit and the beam splitter. An ideal beam splitting mirror would cause the detection pulse L to be incident on the scanning component without changing direction. In practice, however, a small portion of the probing pulse L is reflected by the edge of the beam splitting mirror or the edge of another lens assembly (not shown) and then received by the light receiving device, thereby forming a stray light echo. Therefore, the stray light echo and the echo L 'can be received by the light receiving device, and after the performance of the light emitting device and/or the light receiving device is attenuated, the waveform of the echo L' corresponding to the detection light beam L and the waveform of stray light inside the laser radar have the same change trend, so that the detection pulse generated by the light emitting device in the laser radar and the stray light echo generated by the light receiving device based on the detection pulse are utilized to diagnose the emission performance and/or the receiving performance of the laser radar, no light emitting or light receiving device is required to be additionally arranged, the structure is simple, and the problem that the performance boundary (for example, the maximum detection distance is 200 meters when the reflectivity is 10%) of the laser radar is unexpectedly changed can be effectively identified.
Wherein the unexpected variations include, but are not limited to, the following: for an object with specified reflectivity and specified distance, the laser radar cannot detect the object; or an object is detected, but the reflectivity is lower than expected; or an object is detected, but the reflectivity is higher than expected. Factors that contribute to the unintended variation include: performance degradation of the light emitting device or the light receiving device, such as degradation (attenuation) of a laser to cause reduction in light emission energy or degradation (attenuation) of a detector to cause reduction in echo receiving efficiency, or detection results lower or higher than expected due to hardware failure in the light emitting device or the light receiving device.
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
Fig. 5 shows a flowchart of a diagnosis method for lidar according to an embodiment of the present invention, and the diagnosis method 10 includes steps S11-S14, as follows:
a probe pulse is transmitted at step S11.
Fig. 6 shows a schematic diagram of a laser radar according to an embodiment of the present invention, where the laser radar 20 includes a light emitting device 21 and a light receiving device 22, and the light emitting device 21 emits a detection pulse to the outside of the laser radar 20 after passing through other components, such as a lens assembly, etc.
The stray light echo generated by the probe pulse is received in step S12.
With continued reference to fig. 6, the light emitting device 21 of the laser radar 20 emits a probe pulse, and a probe echo pulse reflected by the target is received by the light receiving device 22. At the same time, stray light generated by the probe pulse in the radar system is also received by the light receiving device 22 of the laser radar 20, and a stray light echo is formed. Wherein, a small part of the detection pulse is reflected by the edge of the optical element and then received by the light receiving device 22 to form stray light; another small portion of the probe pulse is reflected by the mask of the laser radar 20 and received by the light receiving device 22, forming a stray light echo. There are other stray light caused by various reasons, which are not described herein. However, it will be understood by those skilled in the art that the term stray light echo as used herein includes echoes due to reflection, and also includes stray light due to optical crosstalk, etc., and does not limit the technical solution or technical problem solved by the present invention.
The energy of the stray light echo is usually high, so that the stray light echo cannot be distinguished from a detection echo pulse, and a short-distance detection blind area is generated by a laser radar system. When the target is located outside the short-range blind zone of the laser radar 20, as shown in fig. 7, the light receiving device 22 may also receive a probe echo pulse formed by reflecting the probe pulse by the target after receiving the stray light echo. Because the formation time of the stray light echo is determined when the internal structure of the radar system is determined, the stray light echo can be screened out from a plurality of detection echo pulses by receiving the plurality of detection echo pulses generated by the detection pulse.
According to a preferred embodiment of the invention, the stray light echo is an echo pulse within a time window. Fig. 8 shows a time window diagram of the stray light echo with respect to the trigger signal of the light emitting means. The stray light echo is generated immediately after the emission timing of the light emitting device 21, that is, after the trigger signal of the light emitting device 21 is generated, the light emitting device 21 emits a probe pulse, and a part of the probe pulse is normally emitted to the outside of the laser radar 20, and another part of the probe pulse forms a stray light echo in the time window Δ t after the trigger signal is generated, and is finally received by the light receiving device 22.
According to a preferred embodiment of the invention, said time window Δ t comprises a fixed time window, which is related to the size and structure of the lidar 20, and a dynamic time window, which is dynamically adjusted based on the time of reception of the stray light echo. The length of the fixed time window in which the stray light echo is located is determined according to the system characteristics of the laser radar 20, and the fixed time windows in which the stray light echoes of different radar systems are located are different. Generally, the fixed time window Δ t of the stray light echo is determined by the geometric size and the internal structure of the laser radar 20, specifically including the optical path length between the light emitting device 21 and the light receiving device 22 in the laser radar 20, the configuration and the position of the optical device, and the like, and can be known through early measurement.
In fact, a stray light echo formed by a detection pulse in a laser radar system may have a pulse duration longer than a fixed time window Δ t, and therefore, a certain redundancy, that is, a dynamic time window may be set according to the receiving time of the stray light echo. For example, a dynamic time window can be set and adjusted according to the time of the threshold crossing and the peak time of the stray light pulse to obtain a complete stray light echo waveform, which is beneficial to analyzing waveform information subsequently.
For example, in a dirty state of the radar mask, the position of the stray light echo may exceed the range of the fixed time window Δ t. According to the system characteristics, the fixed time window of the stray light echo of the laser radar is determined to be within 10ns after the emission time, and then a dynamic time window of 20-25ns can be set, namely, the light receiving device 22 can receive the echo pulse within 30-35ns after the emission time of the detection pulse and can be used as the stray light echo.
In step S13, a current performance value is acquired from the stray light echo.
With continued reference to fig. 6, the light emitting device 21 emits a probe pulse, and the light receiving device 22 receives a probe echo pulse. When the light emitting device 21 and/or the light receiving device 22 age (attenuate), the waveform of the detection echo pulse changes accordingly, and at the same time, the waveform of the stray light echo changes accordingly, and the change trends of the two are the same. By using the change in the stray light waveform, the laser radar 20 can be diagnosed. Therefore, in this step, the current performance value of the laser radar 20, i.e. the characteristic parameters of the stray light echo, such as the signal amplitude, is obtained first.
According to a preferred implementation of the present invention, in the diagnosis method 10, the step S13 further includes: and when the current performance value is within the preset range, repeating the steps S11-S12 until a plurality of sampling results are obtained. And judging the reasonability of the current performance value to avoid the influence of other factors (such as temperature and other laser light emitting interference). For example, the light emitting device 21 emits a detection pulse specifying the light emission intensity, and determines whether the characteristic parameter of the stray light echo is within a preset range. If so, emitting a detection pulse, receiving a stray light echo generated by the detection pulse, repeating for multiple times, and obtaining multiple sampling results.
According to a preferred implementation of the present invention, in the diagnosis method 10, the step S13 further includes: and acquiring the current performance value based on the average value or the weighted average value of the multiple sampling results. By averaging over multiple measurements, the accuracy of the current performance value can be improved. If the current performance value comprises a plurality of characteristic parameters of the stray light echo, weighted values can be respectively set for the characteristic parameters, and the accuracy of the current performance value can also be improved by obtaining a weighted average value through multiple measurements. For example, when a plurality of feature parameters are used in combination, a method of setting a confidence ratio may be employed, for example: the confidence of the characteristic parameter a is set to 50%, the confidence of the characteristic parameter B is set to 30%, and the confidence of the characteristic parameter C is set to 20%, thereby calculating the current performance value.
In step S14, it is diagnosed whether the laser radar is abnormal or not according to the current performance value and the reference performance value.
Fig. 9 is a schematic diagram showing the waveform change of the stray light echo relative to the trigger signal at the transmitting end, and in conjunction with fig. 6, the light-emitting device 21 transmits a detection pulse after the trigger signal, and the light-receiving device 22 receives the stray light echo within the time window t2-t 1. Before the light emitting device 21 and/or the light receiving device attenuates, the stray light waveform is V0; after attenuation by the light emitting device 21 and/or the light receiving device 22, the stray light waveform is V1. Under the same control quantity of transmitting end trigger signals and the same environmental conditions, the characteristics that the waveform of the stray light changes along with the gradual aging of the light emitting device 21 and/or the light receiving device 22 in the using process are utilized to diagnose whether the laser radar 20 is abnormal or not. That is, the laser radar 20 is diagnosed based on the current performance value and the reference performance value of the stray light echo.
According to a preferred implementation of the invention, the diagnostic method 10 further comprises: under the same specific condition, the current performance value and the reference performance value are respectively obtained, wherein the specific condition comprises one or more of the ambient temperature, the detection field of view and the luminous intensity control quantity. For example, before the laser radar 20 goes offline, the characteristic parameters of the stray light echo received by the light receiving device 22 are used as the reference performance values of the laser radar 20 under the conditions of specifying the temperature interval, the detection field of view and the light intensity control amount (for example, the driving voltage of the laser) determined by calibration. In practical applications, the characteristic parameter of the stray light echo received by the light receiving device 22 is used as the current performance value under the same specific conditions, i.e., under the conditions of a specified temperature interval, a detection field of view and a control amount of the luminous intensity. Thus, the current measurement of the performance value and the reference value have a precondition for comparison. One or more specific conditions may be set as needed, in which the ambient temperature is acquired by a temperature sensor, the detection field of view is obtained by internal configuration information of the laser radar 20, the light emission intensity control amount is acquired by the detection channel light emission state, or the laser is triggered to emit light with a specified light emission intensity within a specified time window when the diagnostic method 10 is performed.
According to a preferred implementation of the invention, the current and/or reference performance values comprise one or more of a peak intensity, a pulse width, and a waveform integral value of the stray light echo. Referring to fig. 9, characteristic parameters of the stray light echo include a peak intensity H1, a pulse width W1, and a waveform integrated value E1. The waveform integrated value is an integrated value of a digital quantity of a stray light echo inside the radar measured by the analog-to-digital converter, namely, a waveform area of the stray light echo. With continued reference to fig. 9, the waveform of the stray light before attenuation by the light emitting device 21 and/or the light receiving device 22 is V0, and its characteristic parameters are used as reference performance values; the stray light waveform attenuated by the light emitting device 21 and/or the light receiving device 22 is V1, and its characteristic parameter is taken as the current performance value. Thus, the current measurement value and the reference value of the performance value have the same comparison parameter, and for example, the transmission/reception performance or the transmission/reception efficiency of the laser radar 20 is diagnosed, so that it is possible to determine whether or not the laser radar 20 is abnormal.
The invention provides a diagnosis method for a laser radar 20, which is suitable for a coaxial optical transceiver system, and diagnoses the transmitting performance and/or receiving performance of the laser radar 20 by using a detection pulse generated by a light-emitting device 21 in the laser radar 20 and a stray light echo generated by a light-receiving device 22 based on the detection pulse, so that whether the performance of the laser radar 20 is abnormal or not can be effectively identified, and the problem that the detection capability of the laser radar 20 is reduced due to the performance attenuation or failure of the light-emitting device 21 and the light-receiving device 22 is solved.
According to a preferred embodiment of the present invention, in the diagnosis method 10, the step S14 further includes: diagnosing whether the laser radar 20 is abnormal based on a deviation between the current performance value and a reference performance value. With continued reference to fig. 9, the waveform of stray light before attenuation by the light emitting device 21 and/or the light receiving device 22 is V0 as a reference performance value; under the same specific conditions, the stray light waveform attenuated by the light emitting device 21 and/or the light receiving device 22 is V1, which is taken as the current performance value. The variation of the stray light echo waveform is used to measure the performance attenuation of the light emitting device 21 and/or the light receiving device 22, thereby determining whether the laser radar 20 is abnormal.
According to a preferred embodiment of the present invention, the lidar 20 includes a light emitting device 21 and a light receiving device 22, and in the diagnosis method 10, the step S14 further includes: based on the current performance value and the reference performance value, it is diagnosed whether or not an abnormality occurs in the luminous intensity of the light emitting device 21 and/or an abnormality occurs in the detection efficiency of the light receiving device 22. For example, after the occurrence of an abnormality in the laser radar 20 is determined based on the current performance value and the reference performance value, the cause of the change in the stray light echo waveform is 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.
According to a preferred embodiment of the present invention, the lidar 20 includes a plurality of detection channels, and in the diagnosis method 10, the step S14 further includes: when the deviation between the current performance value and the reference performance value of the detection channel is larger than a first threshold value, the detection result of the detection channel is corrected. For example, under certain conditions, multiple probe channels are measured sequentially by diagnostic method 10, based on the current performance value and the reference performance value, identifying whether the performance of the probe channel is degraded, and calculating the degradation amount of the performance. When the amount of performance attenuation is larger than the first threshold, the detection result of the channel is corrected to compensate for a measurement error due to attenuation of the light emitting device 21 and/or the light receiving device.
According to a preferred embodiment of the present invention, in the diagnosis method 10, the step S14 further includes: correcting the reflectivity of the detection channel based on a deviation between the current performance value and the reference performance value. For example, based on the current performance value and the reference performance value, whether the performance of the detection channel is attenuated or not is identified, and a performance attenuation amount is calculated and determined. When the amount of performance attenuation is larger than the first threshold, the reflectance of the measured target of the channel is corrected to compensate for a measurement error due to attenuation of the light emitting device 21 and/or the light receiving device 22.
According to a preferred embodiment of the present invention, in the diagnosis method 10, the step S14 further includes: and determining the number of the detection channels of which 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 the detection channels is greater than the threshold. For example, under certain conditions, multiple probe channels are measured sequentially by diagnostic method 10, based on the current performance value and the reference performance value, identifying whether the performance of the probe channel is degraded, and calculating the degradation amount of the performance. And counting the number of the detection channels with the performance attenuation quantity larger than a first threshold value, for example, reporting the fault information when the performance attenuation quantity of one detection channel is larger than the first threshold value.
According to a preferred embodiment of the present invention, in the diagnosis method 10, the step S14 further includes: diagnosing whether the laser radar is abnormal based on whether a deviation between the current performance value and the reference performance value is within an error allowance range. For example, an error allowable range is set according to the tolerance of the radar system to performance degradation, and it is determined whether or not the deviation between the current performance value and the reference performance value is within the error allowable range, thereby diagnosing whether or not the laser radar 20 is abnormal.
Fig. 10 shows a flow chart of a diagnostic method for lidar in accordance with another embodiment of the present invention. The detection pulse generated by the light emitting device in the laser radar and the stray light echo generated by the light receiving device based on the detection pulse are utilized to diagnose the emitting performance and/or the receiving performance of the laser radar, so that whether the performance of the laser radar is abnormal or not 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. The diagnosis method comprises the following steps:
at step S1: a reference performance value is obtained.
Before the laser radar 20 comes off-line, the performance value of the laser radar measured under the condition of specifying the ambient temperature section, the detection field of view, and the control amount of the light intensity of the light emitting device 21 is used as a reference performance value. 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 a reference performance value before the laser radar 20 is aged;
at step S2: under a specific condition, acquiring a current performance value;
wherein the specific condition includes one or more of an ambient temperature, a detection field of view, and a luminous intensity control amount, and the current performance value is acquired under the same specific condition as the reference performance value is acquired. The reference and current performance values include one or more of a peak intensity, a pulse width, and a waveform integral value of the stray light echo.
At step S3: judging whether the current performance value is within a preset range;
and performing reasonableness judgment on the current performance value of each current detection channel to avoid influence of other factors (such as temperature and other laser light emission interference), wherein the reasonableness judgment specifically comprises whether the current performance value is within a preset range, for example, whether the waveform integral value of the stray light echo is within a preset range under the luminous intensity of a specified light emitting device 21.
At step S4: and judging whether the multiple sampling is reached, executing the step S5 when the multiple sampling is completed, and otherwise, executing the step S2 again. The sampling times can be preset and adjustable.
At step S5: judging whether the average value or the weighted average value of the current performance values sampled for multiple times is out of an error allowable range;
the current performance values sampled a plurality of times are averaged or weighted to improve the accuracy of the numerical determination, and 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 amount (i.e., outside the error tolerance). For example, the waveform integrated value of the stray light echo is used as the current performance value, whether the waveform integrated value of the stray light echo is smaller than the difference between the waveform integrated value and the deviation amount in the reference performance value is judged, if yes, step S6 is executed, otherwise, step S8 is executed.
At step S6: judging whether the abnormal times are larger than a threshold value, if the abnormal times are larger than the threshold value, for example, 1 time, executing step S7, that is, judging that there is a fault and reporting the fault, otherwise, executing step S2 again. The abnormal times are the times of the difference between the reference performance value and the deviation amount appearing in the multiple times of sampling, or the number of the detection channels of the difference between the reference performance value and the deviation amount. The threshold value of which can be adjusted.
At step S8: and judging that no abnormity exists, and reporting no fault.
In summary, the diagnostic method 10 is introduced through steps S11-S14, and further described by way of example, therefore, the technical scheme of the invention utilizes the detection pulse generated by the light-emitting device in the laser radar and the stray light echo generated by the light-receiving device based on the detection pulse to diagnose the transmitting performance and/or the receiving performance of the laser radar, wherein the echo pulse comprises a probe echo pulse and a stray light pulse, and when the light emitting device and/or the light receiving device is aged, the waveform change of the detection echo pulse has the same change trend with the waveform of the stray light echo in the laser radar, so that a light source and a light receiving device are not required to be additionally arranged, can effectively identify whether the performance of the laser radar is abnormal or not according to the waveform change of the stray light echo, the problem that the performance of the light emitting device and/or the light receiving device is attenuated or failed to cause the detection capability of the laser radar to be reduced is solved.
The present invention also relates to a computer storage medium comprising computer executable instructions stored thereon which, when executed by a processor, implement the diagnostic method 10 as described above.
The invention also relates to a diagnostic system 30, with reference to fig. 11, the diagnostic system 30 comprising light emitting means 31, light receiving means 32, processing means 33 and storage means 34. Wherein the light emitting device 31 is configured to emit a probe pulse, the light receiving device 22 is configured to receive a stray light echo generated by the probe pulse, and the processing device is configured to obtain a current performance value according to the stray light echo, and diagnose whether an abnormality occurs in the light emitting device 31 and the light receiving device 32 according to the current performance value and a reference performance value. The storage device 34 is configured to store reference performance values. The diagnosis system 30 uses the probe pulse generated by the light emitting device 31 and the stray light echo generated by the light receiving device 32 based on the probe pulse to diagnose the emitting performance of the light emitting device 31 and/or the receiving performance of the light receiving device 32, so as to effectively identify whether the performance abnormality occurs in the light emitting device 31 and/or the light receiving device 32 and to find out the problem of the detection capability reduction.
The invention also relates to a lidar, with reference to fig. 12, the lidar 20 comprising:
a light emitting device 21 including a plurality of lasers 211 configured to emit probe pulses, respectively;
a light receiving device 22 including a plurality of detectors 221 configured to receive stray light echoes generated by the probe pulses, respectively; and
a processing device 23, the processing device 23 being coupled with the light emitting device 21 and the light receiving device 22 and configured to:
acquiring a current performance value according to the stray light echo;
and diagnosing whether the laser radar 20 is abnormal or not according to the current performance value and the reference performance value.
According to a preferred embodiment of the present invention, the light receiving device 21 is further configured to receive the stray light echo generated by the probe pulse under specific conditions, wherein the specific conditions include one or more of an ambient temperature, a probe field of view, and a control amount of light emission intensity.
According to a preferred embodiment of the invention, the stray light echo is an echo pulse within a time window.
According to a preferred embodiment of the present invention, the time window comprises 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 time of reception of the stray light echo.
According to a preferred embodiment of the invention, the current performance value comprises one or more of a peak intensity, a pulse width, and a waveform integration value of the stray light echo.
According to a preferred embodiment of the present invention, the processing device 23 is further configured to: and when the current performance value is within a preset range, obtaining a multi-sampling result.
According to a preferred embodiment of the present invention, the processing device 23 is further configured to: and acquiring the current performance value based on the average value or the weighted average value of the multiple sampling results.
According to a preferred embodiment of the present invention, the processing device 23 is further configured to: diagnosing whether an abnormality of the laser radar 20 occurs based on a deviation between the current performance value and a reference performance value.
According to a preferred embodiment of the present invention, the processing device 23 is further configured to: and diagnosing whether the light emitting intensity of the light emitting device 21 is abnormal and/or the detection efficiency of the light receiving device 22 is abnormal according to the current performance value and the reference performance value.
According to a preferred embodiment of the present invention, the processing device 23 is further configured to: and determining a detection channel with the deviation of the current performance value and the reference performance value larger than a first threshold value, and correcting the detection result of the corresponding detection channel, wherein the plurality of lasers and the plurality of detectors respectively form a plurality of detection channels correspondingly.
According to a preferred embodiment of the present invention, the processing device 23 is further configured to: when the deviation between the current performance value and the reference performance value of the detection channel is larger than a first threshold value, the detection result of the detection channel is corrected.
According to a preferred embodiment of the present invention, the processing device 23 is further configured to: and determining the number of the detection channels of which 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 the detection channels is greater than the first threshold.
According to a preferred embodiment of the present invention, the processing device 23 is further configured to: diagnosing whether the laser radar 20 is abnormal based on whether the deviation between the current performance value and the reference performance value is within an error allowance range.
The light emitting device 21 referred to above includes, for example, the following lasers: a Vertical-Cavity Surface-Emitting Laser (VCSEL); edge Emitting Lasers (EELs). The light receiving device 22 referred to above includes, for example, the following detectors: single Photon Avalanche Diode (SPAD) detectors; avalanche Photodiode (APD) detectors; a Silicon Photomultiplier (SiPM) detector.
The invention diagnoses the transmitting performance and/or receiving performance of the laser radar 20 by using the detection pulse generated by the light-emitting device 21 in the laser radar 20 and the stray light echo generated by the light-receiving device 22 based on the detection pulse, so that whether the performance of the laser radar 20 is abnormal can be effectively identified, and the problem that the detection capability of the laser radar 20 is reduced due to the performance attenuation or failure of the light-emitting device 21 and the light-receiving device 22 is solved.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (25)
1. A diagnostic method for a lidar comprising:
s11: emitting a probe pulse;
s12: receiving stray light echo generated by the detection pulse;
s13: acquiring a current performance value according to the stray light echo;
s14: and diagnosing whether the laser radar is abnormal or not according to the current performance value and the reference performance value.
2. The diagnostic method of claim 1, wherein the current performance value and the reference performance value are each obtained under specific conditions, wherein the specific conditions include one or more of ambient temperature, field of view of detection, and amount of control of luminous intensity.
3. The diagnostic method of claim 1, wherein the stray light echo is an echo pulse within a time window.
4. The diagnostic method of claim 3, wherein the time window comprises a fixed time window and a dynamic time window, the fixed time window being related to a size and a structure of the lidar, the dynamic time window being dynamically adjusted based on a time of receipt of the stray light echo.
5. The diagnostic method of claim 1, the current and/or reference performance values comprising one or more of a peak intensity, a pulse width, and a waveform integration value of the stray light echo.
6. The diagnostic method of claim 1, wherein the step S13 further comprises: when the current performance value is within the preset range, repeating the steps S11-S12 until obtaining a plurality of sampling results.
7. The diagnostic method of claim 6, wherein the step S13 further comprises: and acquiring the current performance value based on the average value or the weighted average value of the multiple sampling results.
8. The diagnostic method of any one of claims 1 to 7, wherein the step S14 further comprises: diagnosing whether the lidar is abnormal based on a deviation between the current performance value and a reference performance value.
9. The diagnostic method according to any one of claims 1 to 7, the lidar comprising a light-emitting device and a light-receiving device, wherein the step S14 further comprises: and diagnosing whether the light emitting intensity of the light emitting device is abnormal and/or the detection efficiency of the light receiving device is abnormal according to the current performance value and the reference performance value.
10. The diagnostic method of any one of claims 1 to 7, the lidar comprising a plurality of detection channels, each detection channel comprising at least one laser and at least one detector, wherein the step S14 further comprises: when the deviation between the current performance value and the reference performance value of the detection channel is larger than a first threshold value, the detection result of the detection channel is corrected.
11. The diagnostic method of claim 10, wherein the step S14 further comprises: correcting the distance and/or reflection information of the detection channel for detecting the object based on the deviation between the current performance value and the reference performance value.
12. The diagnostic method of claim 10, wherein the step S14 further comprises: and determining the number of the detection channels of which 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 the detection channels is greater than the threshold.
13. A computer storage medium comprising computer-executable instructions stored thereon which, when executed by a processor, implement a diagnostic method as claimed in any one of claims 1 to 12.
14. A lidar comprising:
a light emitting device including a plurality of lasers configured to emit probe pulses, respectively;
a light receiving device including a plurality of detectors configured to receive stray light echoes generated by the detection pulses, respectively; and
a processing device coupled with the light emitting device and the light receiving device and configured to:
acquiring a current performance value according to the stray light echo;
and diagnosing whether the laser radar is abnormal or not according to the current performance value and the reference performance value.
15. The lidar of claim 14, wherein the light-receiving device is further configured to obtain the current performance value and the reference performance value, respectively, under specific conditions including one or more of an ambient temperature, a detection field of view, and a luminous intensity control amount.
16. The lidar of claim 14, wherein the stray light echo is an echo pulse within a time window.
17. The lidar of claim 16, wherein the time window comprises a fixed time window and a dynamic time window, the fixed time window being related to a size and a structure of the lidar, the dynamic time window being dynamically adjusted based on a time of receipt of the stray light echo.
18. The lidar of claim 14, wherein the current performance value comprises one or more of a peak intensity, a pulse width, and a waveform integration value of the stray light echo.
19. The lidar of claim 14, the processing device further configured to: and when the current performance value is within a preset range, acquiring a multi-sampling result.
20. The lidar of claim 19, the processing device further configured to: and acquiring the current performance value based on the average value or the weighted average value of the multiple sampling results.
21. The lidar according to any of claims 14-20, wherein the processing device is further configured to: diagnosing whether the lidar is abnormal based on a deviation between the current performance value and a reference performance value.
22. The lidar according to any of claims 14-20, wherein the processing device is further configured to: and diagnosing whether the light emitting intensity of the light emitting device is abnormal and/or the detection efficiency of the light receiving device is abnormal according to the current performance value and the reference performance value.
23. The lidar according to any of claims 14-20, wherein the processing device is further configured to: and determining the detection channels with the deviation of the current performance value and the reference performance value larger than a first threshold value, and correcting the detection result of the corresponding detection channels, wherein each detection channel comprises at least one laser and at least one detector.
24. The lidar of claim 23, the processing device further configured to: when the deviation between the current performance value and the reference performance value of the detection channel is larger than a first threshold value, the detection result of the detection channel is corrected.
25. The lidar of claim 23, the processing device further configured to: and determining the number of the detection channels of which 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 the detection channels is greater than the first threshold.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115184908A (en) * | 2022-06-22 | 2022-10-14 | 苏州一径科技有限公司 | Laser radar anomaly detection method and device, laser radar and storage medium |
| WO2023045424A1 (en) * | 2021-09-23 | 2023-03-30 | 上海禾赛科技有限公司 | Photomask contamination detection method and photomask contamination detection system for laser radar |
| CN117075128A (en) * | 2023-09-11 | 2023-11-17 | 深圳市速腾聚创科技有限公司 | Ranging method, ranging apparatus, electronic device, and computer-readable storage medium |
| WO2024104258A1 (en) * | 2022-11-14 | 2024-05-23 | Hesai Technology Co., Ltd. | Lidar |
| WO2024120491A1 (en) * | 2022-12-07 | 2024-06-13 | Hesai Technology Co., Ltd. | Method and apparatus for detecting obstruction for lidar, and storage medium |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2023045424A1 (en) * | 2021-09-23 | 2023-03-30 | 上海禾赛科技有限公司 | Photomask contamination detection method and photomask contamination detection system for laser radar |
| CN115184908A (en) * | 2022-06-22 | 2022-10-14 | 苏州一径科技有限公司 | Laser radar anomaly detection method and device, laser radar and storage medium |
| CN115184908B (en) * | 2022-06-22 | 2024-01-26 | 苏州一径科技有限公司 | Laser radar anomaly detection method and device, laser radar and storage medium |
| WO2024104258A1 (en) * | 2022-11-14 | 2024-05-23 | Hesai Technology Co., Ltd. | Lidar |
| WO2024120491A1 (en) * | 2022-12-07 | 2024-06-13 | Hesai Technology Co., Ltd. | Method and apparatus for detecting obstruction for lidar, and storage medium |
| CN117075128A (en) * | 2023-09-11 | 2023-11-17 | 深圳市速腾聚创科技有限公司 | Ranging method, ranging apparatus, electronic device, and computer-readable storage medium |
| CN117075128B (en) * | 2023-09-11 | 2024-04-09 | 深圳市速腾聚创科技有限公司 | Ranging method, ranging apparatus, electronic device, and computer-readable storage medium |
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