Pre-processing circuit, laser receiving apparatus, lidar and carrier

Abstract

Disclosed are a pre-processing circuit, a laser receiving apparatus, a LiDAR and a carrier. The pre-processing circuit is used for a LiDAR, and comprises a first conversion circuit and a second conversion circuit, wherein the first conversion circuit is connected to at least one detector of the LiDAR, and is configured to perform first sampling on an output signal of the at least one detector and output first echo data, the first sampling being performed on the basis of a sampling period; and the second conversion circuit is connected to the at least one detector, and is configured to perform second sampling on the output signal of the at least one detector and output second echo data, the second sampling being performed on the basis of a sampling trigger event, which comprises the magnitude of the output signal reaching or exceeding a first threshold value.

Description

Pretreatment circuit, laser receiving device, laser radar, and vehicle

[0001] This application claims priority to Chinese Patent Application No. 202411386789.9, filed September 29, 2024, entitled “Pretreatment circuit, laser receiving device, laser radar, and vehicle,” the contents of which are incorporated by reference in their entirety in the present disclosure. TECHNICAL FIELD

[0002] Embodiments of the present disclosure relate to the field of optical detection technology, and in particular to a pretreatment circuit, a laser receiving device, a laser radar, and a vehicle. BACKGROUND

[0003] Optical detection technology detects objects using light as a medium. Laser has the characteristics of monochromaticity and good directivity compared to ordinary light sources, and object detection using laser as a medium has been widely applied. For example, a laser radar (LiDAR) uses laser as a medium to detect objects and has been widely used in intelligent driving, industrial manufacturing, unmanned aerial vehicles, robot recognition, geographic mapping, and environmental monitoring. The detection performance of the laser radar still needs to be improved in the application process. SUMMARY

[0004] Embodiments of the present disclosure provide a pretreatment circuit, a laser receiving device, a laser radar, and a vehicle to improve the detection performance of the laser radar.

[0005] In a first aspect, a pretreatment circuit for a laser radar is provided. The pretreatment circuit includes: a first conversion circuit connected to at least one detector of the laser radar and configured to perform first sampling on an output signal of the at least one detector to output first echo data, wherein the first sampling is based on a sampling period; and a second conversion circuit connected to the at least one detector and configured to perform second sampling on the output signal of the at least one detector to output second echo data, wherein the second sampling is based on a sampling trigger event, and the sampling trigger event includes the size of the output signal reaching or exceeding a first threshold.

[0006] By providing the first conversion circuit and the second conversion circuit with different sampling logics in the pretreatment circuit, different logics of sampling are performed on the same detector or group of detectors to obtain different sampling results. The first conversion circuit and the second conversion circuit can provide the first echo data and the second echo data to a subsequent circuit. In this way, the subsequent circuit can obtain more diverse echo data, and the adaptability of the laser radar to the environment is improved by utilizing the diversity of the echo data, thereby improving the detection performance of the laser radar.

[0007] Optionally, the first echo data is used to determine a first echo parameter, and the second echo data is used to determine a second echo parameter.

[0008] Optionally, when the laser radar is in the first working mode, the first conversion circuit and the second conversion circuit are in working states at the same time.

[0009] Optionally, when the laser radar is in the second working mode, the first conversion circuit or the second conversion circuit is in a working state.

[0010] Optionally, the first conversion circuit comprises: a first sampling circuit connected with the at least one detector and configured to perform first sampling to determine a first signal; an accumulation circuit connected with the first sampling circuit and configured to determine first echo data based on the first signal; and a storage circuit configured to store the first echo data.

[0011] Optionally, the second conversion circuit is coupled with a first reference signal, the first reference signal is used to represent a first threshold, and the second echo data comprises a time when the output signal reaches the first threshold.

[0012] Optionally, the second conversion circuit is further coupled with a second reference signal, the second reference signal is used to represent a second threshold, and the second threshold is different from the first threshold.

[0013] Optionally, the second conversion circuit comprises a first conversion sub-circuit, the first conversion sub-circuit comprises a comparator, a second sampling circuit and a decoding circuit, wherein: the comparator comprises a first input end, a second input end and an output end, the first input end is used to couple the output signal of the at least one detector, and the second input end is used to couple the reference signal; the second sampling circuit is connected with the output end of the comparator and is configured to perform second sampling to determine a second signal; and the decoding circuit is connected with the second sampling circuit and is configured to output the second echo data based on the second signal.

[0014] Optionally, the preprocessing circuit further comprises: a processing circuit configured to receive at least one of the first echo data or the second echo data, process the at least one of the first echo data or the second echo data, and determine echo information.

[0015] Optionally, the processing circuit is configured to determine a first echo parameter according to the first echo data; and when the first echo parameter is greater than a parameter threshold, the second echo data is used to determine the echo information; or when the first echo parameter is less than the parameter threshold, the first echo data is used to determine the echo information; or when the first echo parameter is equal to the parameter threshold, one or all of the first echo data or the second echo data is used to determine the echo information.

[0016] In a second aspect, a laser receiving device for a lidar is provided, the laser receiving device comprising: at least one detector; and a pre-processing circuit as provided in the first aspect, connected to the at least one detector.

[0017] In a third aspect, a signal processing method is provided, comprising: receiving first return data or second return data; and processing at least one of the first return data or the second return data to determine return information, wherein the first return data is obtained by first sampling an output signal of at least one detector of a lidar, the first sampling being based on a sampling period; and the second return data is obtained by second sampling the output signal of the at least one detector, the second sampling being based on a sampling trigger event, the sampling trigger event comprising the output signal reaching or exceeding a first threshold.

[0018] Optionally, the processing of at least one of the first return data or the second return data to determine the return information comprises: determining a first return parameter from the first return data; when the first return parameter is greater than a parameter threshold, determining the return information using the second return data; or when the first return parameter is less than the parameter threshold, determining the return information using the first return data; or when the first return parameter is equal to the parameter threshold, determining the return information using one or both of the first return data or the second return data.

[0019] In a fourth aspect, a lidar is provided, comprising: at least one detector; a pre-processing circuit as provided in the first aspect, connected to the at least one detector; and a processor connected to the pre-processing circuit, configured to receive data output by the pre-processing circuit and determine point cloud data of the lidar based on the data output by the pre-processing circuit, wherein the data output by the pre-processing circuit comprises one or more of the first return data, the second return data, and the return information.

[0020] In a fifth aspect, a vehicle is provided, comprising: a main body; and a lidar as provided in the fourth aspect, mounted on the main body.

[0021] Optionally, the vehicle comprises a car. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings used in the embodiments description will be exemplarily introduced as follows, and the drawings in the following description are merely the embodiments of the present disclosure, and those skilled in the art can also obtain other drawings according to the provided drawings without any creative effort. The drawings are used to provide further understanding of the present disclosure, and constitute a part of the specification, and are used to explain the present disclosure together with the embodiments of the present disclosure, and do not constitute a limitation on the present disclosure.

[0023] FIG. 1 shows an example block diagram of a lidar consistent with some embodiments of the present disclosure.

[0024] FIG. 2 shows an example block diagram of a pre-processing circuit consistent with some embodiments of the present disclosure.

[0025] FIG. 3 shows an example block diagram of another pre-processing circuit consistent with some embodiments of the present disclosure.

[0026] FIG. 4 shows an example plot of a second sampling of an output signal of a detector consistent with some embodiments of the present disclosure.

[0027] FIG. 5 shows an example block diagram of yet another pre-processing circuit consistent with some embodiments of the present disclosure.

[0028] FIG. 6 shows an example plot of a digital sampling and accumulation of an output of a detector consistent with some embodiments of the present disclosure.

[0029] FIG. 7 shows an example block diagram of yet another pre-processing circuit consistent with some embodiments of the present disclosure.

[0030] FIG. 8 shows an example block diagram of yet another pre-processing circuit consistent with some embodiments of the present disclosure.

[0031] FIG. 9 shows an example flow diagram of a signal processing method consistent with some embodiments of the present disclosure.

[0032] FIG. 10 shows an example block diagram of a signal processing apparatus consistent with some embodiments of the present disclosure. DETAILED DESCRIPTION

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, specific embodiments of the present disclosure will be described below with reference to the drawings. The drawings in the following description are only some embodiments of the present disclosure, and those skilled in the art can obtain other drawings and embodiments according to these drawings without creative labor, and the adjustments and improvements made without departing from the concept of the present disclosure are within the protection scope of the present disclosure.

[0034] In order to make the drawings simple, only the parts related to the corresponding embodiments are shown in the drawings, which do not represent the actual structure of the product. In addition, in order to make the drawings simple and easy to understand, some structures or components are shown in the drawings, and there may be more or less similar structures or components.

[0035] Lidar uses laser as medium to detect objects and has been applied in many fields. For example, lidar can be applied in intelligent driving, industrial manufacturing, unmanned aerial vehicle, robot identification, geographic mapping, or environmental monitoring, etc. Intelligent driving can also be referred to as autonomous driving or assisted driving, including any level of autonomous driving, such as L1-L5, etc. In applications, lidar can be installed on a vehicle to provide the vehicle with perception data, such as point cloud data. The vehicle can use the perception data to realize one or more functions, such as analysis, decision, or control, etc. The vehicle includes, but is not limited to, a vehicle, a manufacturing terminal, a ship, an aircraft (such as a flying vehicle or an unmanned aerial vehicle, etc.), a robot (such as an industrial robot or a household robot, etc.), or a mapping device, etc.

[0036] The lidar can include, but is not limited to, a mechanical rotating lidar, a semi-solid lidar, or a solid lidar. The semi-solid lidar can include, but is not limited to, a micro electro mechanical system (MEMS) lidar, a rotating mirror lidar, a swinging mirror lidar, or a prism lidar, etc. The solid lidar can include, but is not limited to, an optical phase array (OPA) lidar, a flash lidar, or an electronic scanning lidar, etc. When the vehicle is installed with multiple lidars, the types of the multiple lidars can be the same or different.

[0037] FIG. 1 shows an example block diagram of a lidar consistent with some embodiments of the present disclosure. Referring to FIG. 1, the lidar 100 includes a laser emitting circuit 110, a laser receiving circuit 120, an optical system 130, and a control and processing system 150. The laser emitting circuit 110 can emit laser, which is emitted after being adjusted by the optical system 130. The emitted laser encounters an object and is reflected by the object, and the reflected laser back to the lidar 100 can be referred to as a return. The return is emitted to the laser receiving circuit 120 after being adjusted by the optical system 130. The laser receiving circuit 120 receives the return and converts the return into an electrical signal. Return data obtained based on the electrical signal is provided to the control and processing system 150. The control and processing system 150 processes the return data to obtain perception data (such as point cloud data). The control and processing system 150 sends the perception data to the vehicle, which can use the perception data to realize one or more functions, such as analysis, decision, or control, etc.

[0038] The laser emission circuit 110 includes, for example, a driving circuit 111 and a laser 112. The laser 112 can emit laser light under the driving of the driving circuit 111, and the laser light is emitted through the optical system 130. The laser 112 includes, for example, a semiconductor laser, a solid-state laser, a fiber laser, or another type of laser. The semiconductor laser includes, for example, a laser emission circuit, a vertical cavity surface emitting laser (VCSEL), an edge emitting laser (EEL), a distributed feedback laser (DFB), or the like. The above is merely an example, and the embodiments of the present disclosure do not limit the type of laser.

[0039] The laser reception circuit 120 includes, for example, a detector 121. The optical system 130 can converge the echo reflected by the object onto the light-sensitive surface of the detector 121. The detector 121 can convert the optical signal into an electrical signal using the photoelectric effect. Optionally, the laser reception circuit 120 can further include a gating circuit 123. The gating circuit 123 can gate part or all of the detector 121. The detector 121 includes, for example, a photodetector circuit, a PIN photodiode (PIN PD), an avalanche photodiode (APD), a single photon avalanche diode (SPAD), a silicon photomultiplier (SiPM), or the like. The above is merely an example, and the embodiments of the present disclosure do not limit the type of detector.

[0040] The laser reception circuit 120 can further include a preprocessing circuit 140. The preprocessing includes, for example, one or more of amplification, filtering, sampling, or the like. The preprocessing can be implemented by the preprocessing circuit 140. The preprocessing circuit 140 includes, for example, one or more of an amplification circuit, a filtering circuit, or a sampling circuit. The amplification circuit includes, for example, an amplifier, which can amplify the electrical signal converted by the detector. The filtering circuit includes, for example, a filter, which is used to filter out noise or interference. The sampling circuit can sample the electrical signal output by the detector to obtain echo data.

[0041] For example, gating some or all of the detectors 121 includes loading the gated detectors 121 with an operating voltage. The gated detectors 121 are in a state in which they can respond to optical signals and can convert the echoes into electrical signals. For another example, gating some or all of the detectors 121 can include placing the gated detectors 121 in communication with the pre-processing circuitry 140. The pre-processing circuitry 140 can read or process the electrical signals output by the gated detectors 121. For yet another example, gating some or all of the detectors 121 can include gating pre-selected pre-processing circuitry 140. The gated pre-processing circuitry can be placed in communication with the detectors 121 to read or process the electrical signals output by the detectors 121.

[0042] The optical system 130 includes, for example, one or more optical elements such as lenses, mirrors, prisms, homogenizers, or beam splitters. In some embodiments, the optical system 130 includes a transmitting optical element and a receiving optical element. The transmitting optical element, in the transmitting path of the laser light, can shape the laser light emitted by the laser 112 and adjust the path of the emitted laser light. The receiving optical element, in the receiving path of the laser light, can collect the echoes reflected by the object and focus the echoes onto the light-sensitive surface of the detector 121. For example, the transmitting optical element includes one or more optical elements such as transmitting lenses, mirrors, prisms, homogenizers, or beam splitters. For example, the receiving optical element includes one or more optical elements such as receiving lenses, mirrors, prisms, filters, or beam splitters (or dichroic mirrors). The transmitting optical element and the receiving optical element can be independent, partially multiplexed, or fully multiplexed. For example, the lidar can include independent transmitting and receiving optical elements, such as independent transmitting and receiving lenses. For example, the lidar can include a common optical element, such as a beam splitter, for separating the transmitting and receiving paths. For example, the lidar can include a common lens for shaping coaxial beams in the transmitting and receiving paths.

[0043] The control and processing system 150 can process the echo data to obtain perception data. The control and processing system 150 can also send control signaling to the driving circuit 111 to control the driving circuit 111 to drive the laser 112 to emit laser. The control and processing system 150 can also send control signaling to the gating circuit 123 to control the gating circuit 123 to gate part or all of the detectors 121. In some embodiments of the present disclosure, the control and processing system 150 can include one or more processors. The processor includes, for example but not limited to, an application specific integrated circuit (ASIC), a programmable logic device (PLD) implemented hardware circuit, a microcontroller unit (MCU), a micro processor unit (MPU), a digital signal processor (DSP), or a central processing unit (CPU), etc. The PLD implemented hardware circuit can include, for example but not limited to, a field programmable gate array (FPGA), etc. When the control and processing system 150 includes multiple processors, the types of the processors can be the same or different. For example, the control and processing system 150 can include an MCU and an FPGA; or, the control and processing system 150 can include an MCU, an FPGA, and a CPU; or, the control and processing system 150 can include an MCU, a DSP, and an FPGA; or, the control and processing system 150 can include a CPU and an FPGA, etc. When the control and processing system 150 includes multiple processors, the processors can be separately arranged, or partially integrated together, or can be all integrated together. For example, the control and processing system 150 can be implemented in the form of a system on chip (SOC) or an ASIC.

[0044] In some embodiments, the detectors 121 can be integrated on a chip. The pre-processing circuit 140 can be implemented in the form of an ASIC. The detector chip and the pre-processing circuit chip can be hybrid packaged to be implemented in the form of an SOC.

[0045] Optionally, the lidar 100 can also include a scanning system 160. For example, in a mechanical lidar or a semi-solid lidar, the scanning system 160 can include a scanner and a driver, for example. The driver can drive the scanner to rotate, so that the laser achieves scanning of one or both of the vertical or horizontal fields of view. For example, the laser exits through the scanner, and the rotation of the scanner can change the exit path of the laser. For another example, the echo of the laser can enter the scanner and be guided to the light receiving path through the scanner. The embodiments of the present disclosure do not limit the type of scanner, which can include but is not limited to a rotating mirror, a swing mirror, a vibrating mirror, or other components that can direct the laser to different directions in the environment, etc. For another example, the scanning system 160 can include a rotating platform. One or more of the laser emission circuit, the laser receiving circuit, or the optical system, etc. can be arranged on the rotating platform. With the rotation of the rotating platform, scanning of one or both of the vertical or horizontal fields of view is achieved. When the lidar 100 includes the scanning system 160, the control and processing system 150 can also control the motion of the scanning system 160.

[0046] In some embodiments, the lidar 100 can not include a scanning system. There can be no mechanical rotating components in the lidar. For example, the lidar 100 includes a plurality of lasers 112 and a plurality of detectors 121. The plurality of lasers 112 and the plurality of detectors 121 are arranged in a two-dimensional array. The lasers 112 at different positions in the two-dimensional array emit lasers that exit towards different angles after passing through the optical system 130, thereby achieving two-dimensional scanning of the lidar.

[0047] During detection, changes in the environment can affect the detection performance of the lidar. For example, the detector of the lidar can enter a saturation state when it is in a strong light environment, causing the signal output by the detector to fail to truly reflect the situation of the echo, thereby affecting the detection performance of the lidar. The following takes a detector including a SPAD as an example for illustration.

[0048] The SPAD has high sensitivity and can work under weak light conditions, and can even detect a single photon. However, when the SPAD is in a strong light condition, too many photons enter the SPAD, causing the SPAD to enter a saturation state. In the saturation state, the response capability of the SPAD to the photons has reached the limit, and the output electrical signal can fail to change with the increase in the intensity of the echo. At this time, the output electrical signal of the SPAD can no longer accurately reflect the true situation of the echo, which can affect the detection performance of the lidar.

[0049] In some embodiments of the present disclosure, the response capability of the SPAD array to light can be improved by increasing the number of SPADs in the laser receiving circuit. The SPAD array can include a plurality of SPAD subsets. For example, the electrical signal output by one SPAD subset can be used to obtain echo information of one angle. When part of the SPADs in the subset are triggered by photons and are in a dead time, other SPADs can still respond to photons. The total current or the number of triggers output by the SPAD subset reflects the intensity of light. However, in the limited internal space of the laser radar, the number of SPADs that can be set is limited. The number of SPAD subsets or the number of SPADs included in the SPAD subset is limited. Increasing the number of SPADs can alleviate the saturation phenomenon of the detector caused by strong light to a certain extent. The detection performance of the laser radar still needs to be improved.

[0050] Some schemes are provided in embodiments of the present disclosure, for example, including a preprocessing circuit, a laser receiving device, a signal processing method and device, a laser radar, and a vehicle, etc., which can improve the adaptability of the laser radar to the environment, so that the laser radar has good detection performance in different environments.

[0051] The following will be described with reference to the accompanying drawings.

[0052] FIG. 2 shows an example block diagram of a preprocessing circuit according to some embodiments of the present disclosure. Please refer to FIG. 2. The preprocessing circuit 200 can be used in a laser radar. The preprocessing circuit 200 includes a first conversion circuit 210 and a second conversion circuit 220. The first conversion circuit 210 and the second conversion circuit 220 are connected with a detector 221 of the laser radar. The first conversion circuit 210 can perform first sampling on the output signal of the detector 221, and convert the first signal obtained by the first sampling into first echo data. The first sampling is based on a sampling period. The second conversion circuit 220 can perform second sampling on the output signal of the detector 221, and convert the second signal obtained by the second sampling into second echo data. The second sampling is based on a sampling trigger event. The sampling trigger event includes, for example, that the size of the output signal reaches or exceeds a threshold.

[0053] The lidar can include one or more detector chips. A detector chip can include multiple detectors. When a detector chip includes multiple detectors, the first conversion circuit 210 and the second conversion circuit 220 can sample the detectors independently. Or the first conversion circuit 210 and the second conversion circuit 220 can sample the detectors in groups. For example, a detector chip of the lidar can include multiple groups of detectors. The first conversion circuit 210 and the second conversion circuit 220 can sample the output signals of the multiple detectors in a group in the group. The number of detectors included in different groups of detectors can be the same or different. Alternatively, some groups can include one detector. Some groups can include multiple detectors. The first conversion circuit 210 and the second conversion circuit 220 can be connected to one or a group of detectors, and sample different detectors or the same group of detectors.

[0054] For example, the detectors include SPADs. A detector chip includes multiple subsets of SPADs. A subset of SPADs can include multiple SPADs. The electrical signals output by a subset of SPADs can be sampled by the first conversion circuit 210 or the second conversion circuit 220.

[0055] In some embodiments, a number of first conversion circuits 210 can be provided in the lidar, consistent with the number of subsets of SPADs. In some embodiments, a number of second conversion circuits 220 can be provided in the lidar, consistent with the number of subsets of SPADs. A first conversion circuit 210 or a second conversion circuit 220 can sample the electrical signals output by the subset of SPADs connected thereto. In some embodiments, the number of first conversion circuits 210 and the number of second conversion circuits 220 can be less than the number of subsets of SPADs. The first conversion circuits 210 and the second conversion circuits 220 can be connected to different subsets of SPADs by gating. The first conversion circuit 210 or the second conversion circuit 220 can sample different subsets of SPADs in time division.

[0056] In the above embodiments, the first conversion circuit and the second conversion circuit with different sampling logics are provided in the preprocessing circuit. The first conversion circuit and the second conversion circuit sample a subset of SPADs with different logics respectively, and obtain different sampling results. The different sampling results can be converted into the first echo data and the second echo data and provided to the downstream circuit. In this way, the downstream circuit can obtain more diverse echo data. The diversity of the echo data can improve the adaptability of the lidar to the environment, and thus improve the detection performance of the lidar.

[0057] For example, the first sampling based on the sampling period can periodically sample and quantize the output signal of the detector. The sampling signal obtained by the periodic sampling can more accurately reflect the slight change of the output signal, for example, the waveform of the output signal can be recovered. For the case where the output signal waveform changes slowly, it is beneficial to obtain more abundant echo information in the case where the echo intensity is relatively weak. The second sampling based on the sampling trigger event can quickly respond to the change of the output signal when the output signal changes rapidly, and measure the time of flight of the laser with high precision. It is beneficial to obtain more accurate time of flight in the case where the echo is relatively strong. The first conversion circuit and the second conversion circuit of the preprocessing circuit are set with the above two sampling logics, so that the laser radar can obtain echo data more suitable for the current echo condition when facing different echo intensities. More accurate perception data can be obtained using the echo data to improve the adaptability of the laser radar to the environment and improve the detection performance of the laser radar as a whole.

[0058] The disclosure embodiments do not limit the sampling frequency (or sampling period) of the first sampling, which can be set as needed. The higher the sampling frequency, the higher the degree of recovery of the output signal of the detector, the higher the processing amount of the first conversion circuit, and the higher the power consumption. The lower the sampling frequency, the lower the degree of recovery of the output signal of the detector. The processing amount of the first conversion circuit is reduced, and the power consumption is also reduced. In the sampling frequency design, the sampling frequency can be designed by considering the power consumption and the recovery degree of the signal. In some embodiments of the disclosure, the sampling frequency of the first sampling can be designed to be greater than or equal to twice the highest frequency of the output signal based on the Nyquist sampling theorem, so as to reduce the aliasing phenomenon.

[0059] In some embodiments of the disclosure, the first echo data can be used to determine the first echo parameter. The second echo data can be used to determine the second echo parameter. The first echo parameter and the second echo parameter can be the same or different. For example, the first echo parameter or the second echo parameter can include one or more of the following parameters: peak intensity of the echo pulse, number of echo pulses, arrival time of the echo pulse, pulse width of the echo pulse, slope of the echo pulse, or area of the echo pulse, etc. The above echo parameters can be used to determine echo information, such as echo time or echo intensity, etc.

[0060] The echo parameters (e.g., at least one of the first echo parameters or the second echo parameters) can be determined by a post-stage circuit of the first conversion circuit 210 and the second conversion circuit 220. The post-stage circuit can include a processing circuit, for example. The processing circuit can be part of a control and processing system of the lidar, or can be part of a pre-processing circuit. The processing circuit can perform waveform analysis on the echo data to obtain one or more of the above parameters, for example. The first echo parameters and the second echo parameters can be used to determine one or more of echo times or echo intensities. An echo time can indicate a time at which an echo reaches a detector of the lidar, for example. The echo time can be used to determine a time of flight of a laser, to determine a distance of an object from the lidar. The echo time can be determined by a threshold-crossing time of a rising edge or a falling edge of an echo pulse. The threshold-crossing time can be a time at which a rising edge of an echo pulse reaches a threshold during a rising process, for example. The threshold-crossing time can be the echo time. An echo intensity can indicate a light intensity of an echo. The echo intensity can be related to a reflectivity of an object, and can be used for one or more of target identification, target classification, or noise filtering. The echo intensity can be determined based on one or more of a peak intensity of an echo pulse, a pulse width of an echo pulse, a slope of an echo pulse, or an area of an echo pulse, for example.

[0061] FIG. 3 shows an example block diagram of another pre-processing circuit, consistent with some embodiments of the present disclosure. Referring to FIG. 3, the pre-processing circuit 300 includes a first conversion circuit 310 and a second conversion circuit 320. The first conversion circuit 310 and the second conversion circuit 320 are connected to a detector 321 of a lidar. The first conversion circuit 310 is the same as or similar to the first conversion circuit 210. The second conversion circuit 320 is the same as or similar to the second conversion circuit 220. The pre-processing circuit 300 further includes a processing circuit 330. The processing circuit 330 can receive the first echo data and the second echo data, and process one or both of the first echo data or the second echo data to determine echo information.

[0062] In some embodiments of the present disclosure, the processing circuit 330 can be integrated in the pre-processing circuit 300. In some other embodiments of the present disclosure, the processing circuit 330 can be independent of the pre-processing circuit 300, e.g., as part of a control and processing system of the lidar. The processing circuit 330 can include any of the processors described in the above embodiments, e.g., a DSP or an FPGA, for example.

[0063] In some embodiments of the present disclosure, the processing circuitry can determine a first echo parameter from the first echo data. The first echo parameter can reflect a first echo intensity. The processing circuitry can determine the echo information using the second echo data when the first echo parameter is greater than a parameter threshold. Alternatively, the processing circuitry can determine the echo information using the first echo data when the first echo parameter is less than the parameter threshold. Alternatively, the processing circuitry can determine the echo information using one or both of the first echo data and the second echo data when the first echo parameter is equal to the parameter threshold. The first echo parameter can include any one or more of the echo parameters described above that can determine the echo intensity, such as: a peak intensity of the echo pulse, a number of the echo pulses, a pulse width of the echo pulse, a slope of the echo pulse, or an area of the echo pulse, etc. The parameter threshold is related to the selected echo parameter. For example, when the peak intensity of the echo pulse is selected, the parameter threshold includes an intensity threshold; and the like.

[0064] In some embodiments, the first conversion circuitry can obtain more abundant echo information when the echo intensity is weak. The second conversion circuitry can obtain more accurate echo time when the echo intensity is strong.

[0065] For example, by analyzing the first echo data, a first echo parameter reflecting the echo intensity can be obtained. The first echo parameter can be compared with a parameter threshold, and based on the comparison result, it is determined which echo data output by the first conversion circuit is used to determine the echo information. In this way, the output of the first conversion circuit can be reused to determine whether the current echo condition is more suitable for using the first echo data or the second echo data as the detection result of the lidar, which can improve the detection accuracy of the lidar. The disclosure embodiments do not limit the size of the parameter threshold, which can be set according to the selected parameter and the detector of the lidar. For example, the parameter threshold can be a strong-weak boundary of the echo intensity. When the boundary is exceeded, the detector is more likely to reach saturation. In a scenario with high echo intensity, the number of incident photons to the detector is large. When the number of incident photons is such that the first echo parameter is greater than the parameter threshold, the detector is more likely to reach saturation. At this time, it is more suitable to select the second echo data to determine the echo information to obtain the perception data of the lidar. In a scenario with low echo intensity, the number of incident photons to the detector is small. For example, the number of incident photons is such that the first echo parameter is less than the parameter threshold, and the first echo data can be used to determine the echo information to obtain the perception data of the lidar. At this time, the processing circuit can receive the second echo data, or can not receive the second echo data. When the second echo data is received, the first echo data can be selected to determine the echo information, or the first echo data and the second echo data can be selected to determine the echo information, or the second echo data can be selected to determine the echo information, and the disclosure embodiments do not limit this. For a scenario in which the number of incident photons is such that the first echo parameter is equal to the parameter threshold, the disclosure embodiments do not limit this, and one or all of the first echo data or the second echo data can be selected to determine the echo information.

[0066] Please continue to refer to FIG. 2. In some embodiments of the disclosure, the first conversion circuit 210 can be coupled to a clock signal CLK, and the first sampling is performed based on the clock signal CLK. The first conversion circuit 210 can also be coupled to other periodic trigger signals, and the periodic first sampling is performed based on the trigger signals. The second conversion circuit 220 can be coupled to a reference signal Rf (for the convenience of distinguishing the description, it can be referred to as a first reference signal). The second sampling is used to output a second signal when the size of the output signal reaches or rises to exceed the reference signal Rf. The second sampling can also output the second signal when the size of the output signal reaches or falls to be less than the reference signal Rf. Accordingly, the second sampling can obtain the time when the output signal rises to Rf and the time when the output signal falls to Rf, and the duration when the amplitude of the output signal exceeds Rf. The second echo data can include a digital signal converted by the second signal, for example, a digital signal obtained by decoding the second signal.

[0067] In some embodiments, the reference signal Rf can be used to represent the first threshold. For example, the first threshold can be the above parameter threshold.

[0068] In some embodiments, the number of reference signals Rf can be one or more. When the number of reference signals is more than one, the sizes of the plurality of reference signals are different, and each of the plurality of reference signals is used to represent a different threshold value. For example, in some embodiments of the present disclosure, the second conversion circuit 220 is coupled to a plurality of reference signals with different sizes. The plurality of reference signals are used to represent a plurality of threshold values. One reference signal is used to represent one threshold value. The first reference signal can be any one of the plurality of reference signals. The threshold value represented by the first reference signal can be any one of the plurality of threshold values. For example, the plurality of threshold values includes a first threshold value.

[0069] For example, FIG. 4 shows an example diagram of a second sampling of the output signal of the detector, consistent with some embodiments of the present disclosure. Referring to FIG. 4, the horizontal axis represents time t, and the vertical axis represents the amplitude S of the output signal. By setting a plurality of threshold values with different sizes (for example, threshold values Th1-Th3), the threshold crossing times of different threshold values (for example, the times t1-t3 of the rising edges, or the times of the falling edges) can be obtained. Based on the obtained plurality of threshold crossing times, the waveform of the output signal of the detector can be determined. The second sampling can sample the threshold crossing times with high precision, and can obtain high-precision echo times, and can also determine information such as echo intensity, thereby improving the detection performance of the lidar under strong echoes. For example, when the echo is strong, even if the detector is saturated, the pulse front edges generated by different echo intensities will have slight differences in slope. By collecting a plurality of threshold crossing times through the second sampling, the slope of the pulse front edge can be determined, the echo intensity can be determined, and thus the detection performance of the lidar can be improved.

[0070] In some embodiments of the present disclosure, the power consumption of the lidar can be reduced by setting the size of the threshold value. For example, the threshold value can be raised so that the second conversion circuit outputs the second echo data only when the echo intensity is high. When the echo intensity is low, the second echo data can not be outputted, so as to reduce the power consumption of the lidar. In addition, raising the threshold value can also effectively reduce the jitter of the threshold crossing time caused by noise. Embodiments of the present disclosure do not limit the value of the threshold value, which can be set according to the detection effect of the lidar.

[0071] For example, in some embodiments of the present disclosure, the threshold value can be set based on the amplitude of the output signal of the channel or pixel of the lidar in the first state. The first state, for example, includes a state in which the intensity of the echo is such that more than a preset proportion of the detectors (e.g., more than half of the detectors) corresponding to the channel or pixel are triggered. A channel or pixel of the lidar can correspond to one or more detectors. Taking the example of a laser receiving circuit of the lidar including a SPAD array, a channel or pixel of the lidar can correspond to a SPAD subset. The SPAD subset includes a plurality of SPADs. When more than 50% of the SPADs in a SPAD subset are triggered, the threshold value can be set based on the amplitude of the output signal of the SPAD subset at this time. For example, the number of SPADs included in a SPAD subset is X, the single-photon response amplitude is 1 mV, and the threshold value is set to the amplitude of the output signal when more than 60% of the SPADs in the SPAD subset are triggered, the threshold value can be set to 60% * X * 1 (mV) = 0.6X (mV). If an amplifier is also provided at the output end of the SPAD subset, and the amplification factor of the amplifier is Y, the threshold value can be set to 0.6XY (mV) at this time.

[0072] Embodiments of the present disclosure do not limit the type of detector, which can include any of the detectors described in the above embodiments. The detector can provide an output signal in the form of a digital signal or an analog signal.

[0073] The first conversion circuit and the second conversion circuit are described below, respectively.

[0074] In some embodiments of the present disclosure, the first conversion circuit can include a digital sampling and accumulation circuit or an analog-to-digital conversion circuit. The digital sampling and accumulation circuit can be used to sample and process a digital signal. The analog-to-digital conversion circuit can be used to sample and process an analog signal.

[0075] FIG. 5 shows an example block diagram of another pre-processing circuit, consistent with some embodiments of the present disclosure. FIG. 5 describes an example in which the lidar includes a detector array 522. The detector array 522 can provide an output signal in the form of a digital signal. Referring to FIG. 5, the pre-processing circuit 500 includes a first conversion circuit 510 and a second conversion circuit 520. The first conversion circuit 510 can include a digital sampling and accumulation circuit. The digital sampling and accumulation circuit can perform digital sampling on the signal output by the detector and perform accumulation processing. For example, the first conversion circuit 510 can include a first sampling circuit 511, an accumulation circuit 512, and a storage circuit 513. The first sampling circuit 511 can perform sampling on one or a group of detectors in the detector array. The accumulation circuit 512 can accumulate the digital signal sampled by the first sampling circuit 511 to obtain first echo data. The storage circuit 513 can store the first echo data.

[0076] Taking the example that the detector array 522 comprises a SPAD array, the first sampling circuit 511 can be connected with one or more SPADs. The first sampling circuit 511 can periodically sample the output of the one or more SPADs based on a periodic clock signal CLK. For example, the first sampling circuit 511 can periodically sample the output of a subset of SPADs. One rising edge or one falling edge of the CLK can trigger the first sampling circuit 511 to sample once. The output signal of a triggered SPAD can be recorded as “1”. The output signal of an untriggered SPAD is not counted, or is not counted as “0”. For the case that the first conversion circuit 510 is connected with the output signal of a subset of SPADs, the first sampling circuit 511 can sample the number of SPADs in the subset of SPADs that are triggered at the sampling time. The number of triggered SPADs can reflect the intensity of the received light.

[0077] For example, the first conversion circuit 510 samples the number of triggers of a SPAD triggered at the rising edge or the falling edge of the clock signal CLK, to obtain the sampling time and the corresponding number of triggers. Based on the time when the laser emits the laser and the sampling time, the time of flight corresponding to the sampling time can be determined. Accordingly, a sequence of periodically increasing time of flights and the number of triggers corresponding to each time of flight can be determined. The number of triggers changing with the time of flight can be represented as the echo curve shown in FIG. 4.

[0078] For another example, when the laser radar detects information of a spatial angle, the laser can be emitted multiple times for the spatial angle, and the echoes are received respectively. The detection of a spatial angle comprises multiple transmission and reception cycles. The detector receives the echoes corresponding to each emission of the laser. The first sampling circuit 511 can sample the output of the detector in the multiple transmission and reception cycles respectively. The accumulation circuit 512 can accumulate the number of SPAD triggers in different transmission and reception cycles corresponding to the same time of flight, and store in the storage circuit 513.

[0079] The SPAD has high sensitivity and is easy to be triggered by ambient light, which produces noise in the echo information. The distribution of ambient light with the time of flight is relatively random. The time of flight corresponding to the echo pulse in each transmission and reception cycle is basically consistent. By accumulating the number of triggers in different transmission and reception cycles, the signal amplitude corresponding to the echo pulse can be increased, which is conducive to filtering out the interference of ambient light and improving the signal-to-noise ratio of detection.

[0080] For example, FIG. 6 shows an example of a curve diagram of digital sampling and accumulation of the output of the detector, consistent with some embodiments of the present disclosure. The horizontal axis represents the time of flight t, and the vertical axis represents the number of triggered SPADs n. The curve can reflect the relationship between the number of triggered SPADs and the time of flight. As can be seen, the full waveform can be obtained by the first conversion circuit, and rich echo information can be obtained. In this way, using the echo waveform, the time of flight of the echo can be determined, and the ambient light noise or echo intensity can also be determined. For example, the area of the curve in the sampling time period T can represent the integral of the number of SPAD triggers, and can represent the echo intensity.

[0081] In some other embodiments of the present disclosure, the first conversion circuit can include an analog-to-digital conversion circuit, which can sample the signal output by the detector and quantize it into a digital signal. For example, the analog-to-digital conversion circuit can sample the number of SPAD triggers. The embodiments of the present disclosure do not limit the type of analog-to-digital conversion circuit, which can include but is not limited to a pipeline analog-to-digital converter (ADC), a successive approximation ADC (SAR ADC), an integrating ADC, a parallel comparison ADC, or a voltage-to-frequency conversion ADC, etc.

[0082] The pre-processing circuit 500 can include a plurality of first conversion circuits 510. In this way, parallel sampling and conversion of the detector array can be achieved to improve the processing efficiency of the pre-processing circuit 500.

[0083] FIG. 7 shows a structure example of another pre-processing circuit, consistent with some embodiments of the present disclosure. Please refer to FIG. 7, the pre-processing circuit 700 includes a first conversion circuit 710 and a second conversion circuit 720. The second conversion circuit 720 includes at least one conversion sub-circuit, for example, including conversion sub-circuits 721 to 72N. N represents the number of conversion sub-circuits, and N is greater than or equal to 1. The conversion sub-circuit 72i (i∈[1, N]) includes a comparator Cp, a second sampling circuit Sp, and a decoding circuit Dc. The comparator Cp includes a first input terminal, a second input terminal, and an output terminal. The first input terminal can be coupled to the output signal of the detector 731. The second input terminal can be coupled to a reference signal Rfi (i∈[1, N]). The second sampling circuit Sp can be connected to the output terminal of the comparator Cp. The second sampling circuit Sp can perform a second sampling when the signal output by the output terminal of the comparator Cp flips. The decoding circuit Dc is connected to the second sampling circuit Sp. The decoding circuit Dc can decode the second signal sampled by the second sampling circuit Sp to obtain a digital signal. The digital signal can be used to indicate the time of the second sampling. The second sampling is triggered when the comparator Cp flips. The comparator Cp flips when the output signal of the detector rises above the reference signal Rfi, or when the output signal falls below the reference signal Rfi. In this way, it is equivalent to indicating the rising time of the output signal of the detector. The second input terminals of the comparators of different conversion sub-circuits can be coupled to different reference signals. One reference signal is used to represent one threshold. Accordingly, the second conversion circuit 720 can sample the rising time of the output signal of the detector at different thresholds, further improving the detection accuracy. The decoding circuit Dc, for example, includes a decoder. The decoder can decode the second signal sampled by the second sampling circuit Sp to obtain a digital signal.

[0084] Please continue to refer to FIG. 7, in some embodiments of the present disclosure, the pre-processing circuit 700 can also include an amplifier 730. The amplifier 730 is arranged between the output terminal of the detector 731 and the input terminal of the second conversion circuit 720. The input terminal of the second conversion circuit 720, for example, includes the first input terminal of the comparator Cp of the conversion sub-circuit 72i. In some embodiments of the present disclosure, the amplifier 770, for example, includes a transimpedance amplifier (TIA) to convert the current signal output by the detector into a voltage signal. Optionally, the amplifier 770 can also amplify the output signal of the detector, so that the output signal of the detector is more easily compared with the reference signal. Optionally, the amplifier 770 can also integrate a filtering function to suppress high-frequency noise in the output signal of the detector. This helps to weaken or eliminate high-frequency interference in the output signal of the detector, improving the quality of the output signal of the detector.

[0085] In some embodiments of the present disclosure, the second conversion circuit can sample the output signal of one or more detectors through a sampling resistor. For example, FIG. 8 shows a structural example diagram of another pre-processing circuit consistent with some embodiments of the present disclosure. Referring to FIG. 8, one end of the sampling resistor R can be connected to the output end of the detector 731 and the input end of the second conversion circuit 720, and the other end can be coupled to a supply voltage V.

[0086] For example, in a SPAD array, a common sampling resistor R is connected to the output end of a SPAD subset. The first input end of the comparator Cp is connected between the output end of the SPAD or the SPAD subset and the sampling resistor R.

[0087] In some other embodiments of the present disclosure, the second conversion circuit 720 can sample the output signal of one or more detectors by connecting the output end of one or more detectors through capacitive coupling. For example, in a SPAD array, the output end of a SPAD subset is connected to one end of a capacitor. The other end of the capacitor is connected to the first input end of the comparator Cp.

[0088] The second input end of the plurality of comparators Cp of the second conversion circuit 720 can be connected to different reference signals. Different reference signals correspond to different threshold values. In this way, the over-threshold time of the second sampled waveform with rapidly changing front can be obtained. The time accuracy of the second sampling is very high, reaching the ps level. Under the condition of strong echo with rapidly changing waveform, the second sampling can not only obtain high-precision echo time, but also obtain more echo information, which can improve the detection performance of the laser radar.

[0089] In some embodiments of the present disclosure, when the laser radar is in the first working mode, the first conversion circuit 210 and the second conversion circuit 220 are in working state at the same time. When the laser radar is in the second working mode, one of the first conversion circuit 210 and the second conversion circuit 220 is in working state.

[0090] For example, the first working mode can be referred to as a normal working mode. The second working mode can be referred to as a low-power-consumption working mode (or power-saving mode). When the laser radar is in the first working mode, the first conversion circuit 210 and the second conversion circuit 220 are in the working state at the same time. The echo data obtained by the laser radar can be enriched, and the diversity of the echo data is used to improve the adaptability of the laser radar to the environment and improve the detection performance of the laser radar. When the laser radar is in the second working mode, the power consumption thereof can be saved. When the vehicle has a demand for reducing power consumption, one of the first conversion circuit 210 and the second conversion circuit 220 can be selected to pre-process the output signal of the detector. In this way, the power consumption of the laser radar can be reduced to meet the scene demand of the vehicle for low power consumption. Optionally, when the laser radar is in the second working mode, the second conversion circuit 220 is in the working state. The second sampling is based on a sampling trigger event, and has lower power consumption than the first sampling based on a period. Therefore, the second conversion circuit 220 has lower power consumption than the first conversion circuit 210. When the laser radar is in the second working mode, selecting the second conversion circuit 220 to be in the working state can have a better power saving effect. For example, the application scenario of the second working mode includes that the vehicle is in a standby state. At this time, the change of the object around the laser radar is relatively small, and pre-processing the output signal of the detector by using the second conversion circuit 220 can meet the detection demand in this scene. The power consumption of the laser radar can be saved, and the energy consumption of the vehicle can be reduced.

[0091] In some embodiments of the present disclosure, the laser radar can further include a third working mode. In the third working mode, the laser radar can determine to use the data of the first conversion circuit 210 or the second conversion circuit 220 based on the amplitude of the echo signal. For example, the first conversion circuit 210 can be used to determine the amplitude of the received echo signal. If the amplitude of the echo signal is less than a preset threshold, the first conversion circuit 210 continues to be used to perform the first sampling on the output signal of the detector. At this time, the second conversion circuit 220 can be in a dormant state, and the power consumption can be saved. If the amplitude of the echo signal reaches or exceeds the preset threshold, the second conversion circuit 220 is used to perform the second sampling on the output signal of the detector. The preset threshold can be set according to actual demand, and the present disclosure does not limit this. In this way, by setting the preset threshold, the application scenarios of the first conversion circuit 210 and the second conversion circuit 220 are distinguished, and the flexibility of the laser radar is improved.

[0092] The embodiments of the present disclosure further provide a laser receiving device. The laser receiving device is used in a laser radar. The laser receiving device includes at least one detector and a pre-processing circuit. The pre-processing circuit is connected with the at least one detector. The pre-processing circuit can be the pre-processing circuit provided by the embodiments of the present disclosure.

[0093] FIG. 9 shows a flow diagram of a signal processing method according to some embodiments of the present disclosure. Referring to FIG. 9, the signal processing method can include:

[0094] S910: receiving first echo data or second echo data. The first echo data is obtained by converting a first signal. The first signal is obtained by first sampling an output signal of at least one detector of a laser radar. The first sampling is based on a sampling period. The second echo signal is obtained by converting a second signal. The second signal is obtained by second sampling the output signal of the at least one detector. The second sampling is based on a sampling trigger event. The sampling trigger event includes the size of the output signal reaching or exceeding a first threshold.

[0095] S920: processing one or both of the first echo data or the second echo data to determine echo information.

[0096] The descriptions of the first echo data, the second echo data, the first sampling, and the second sampling can refer to the above embodiments.

[0097] For example, in some embodiments of the present disclosure, the above step S920 can include, for example, determining a first echo parameter according to the first echo data. When the first echo parameter is greater than a parameter threshold, the second echo data is used to determine the echo information. Or, when the first echo parameter is less than the parameter threshold, the first echo data is used to determine the echo information. Or, when the first echo parameter is equal to the parameter threshold, one or both of the first echo data or the second echo data is used to determine the echo information.

[0098] Some embodiments of the present disclosure also provide a signal processing apparatus including units or means for performing each step of any of the signal processing methods provided by the above embodiments. For example, FIG. 10 shows a structural diagram of a signal processing apparatus according to some embodiments of the present disclosure. Referring to FIG. 10, the signal processing apparatus 1000 can include, for example, an interface unit 1010 and a processing unit 1020. The interface unit 1010 is configured to receive first echo data and second echo data. The processing unit 1020 is configured to process one or both of the first echo data or the second echo data to determine echo information. The signal processing apparatus 1000 includes, for example, a processor. The interface unit 1010 includes, for example, a bus interface of the processor in communication with other circuits. The processing unit 1020 includes, for example, a processing core of the processor.

[0099] For example, some embodiments of the present disclosure also provide a signal processing apparatus. The signal processing apparatus can include a processor. The processor can be coupled to a memory. The memory stores instructions. When the instructions are invoked by the processor, the processor can perform any of the signal processing methods in the above method embodiments.

[0100] The embodiments of the present disclosure further provide a computer-readable storage medium. The computer-readable storage medium comprises instructions stored thereon. When the instructions are invoked by a processor, any one of the signal processing methods in the above embodiments is executed. The embodiments of the present disclosure further provide a computer program (or computer program product). The computer program comprises instructions. When the instructions are invoked by a processor, any one of the signal processing methods in the above embodiments is executed.

[0101] In the embodiments of the present disclosure, the output signal of the at least one detector can include a signal output by one detector, or can include a signal output by a group of detectors. The detector or the group of detectors can output the signal through a corresponding readout circuit.

[0102] In the present disclosure, "connection" includes direct connection or indirect connection between objects: the connection between objects can be directly connected through a medium (for example, a wire, a trace, etc.), or can be indirectly connected through other elements, or can be internally connected. "Coupling" includes signal connection between objects, which can be directly connected through a medium (for example, a wire, a trace, etc.), or can be connected through other elements, etc.

[0103] In the present disclosure, unless otherwise explicitly specified and limited, ordinal numbers such as "first", "second", etc. are only used to distinguish the description of the associated objects, and cannot be understood as indicating or implying the relative importance or order between the associated objects. In addition, the ordinal numbers do not represent the number of the associated objects. For example, "the first laser radar" can include one laser radar, or a plurality of laser radars.

[0104] "Multiple" includes two or more, and other quantifiers are similar.

[0105] The term "or", "and / or" in the present disclosure is used to describe the relationship between the associated objects, which means non-exclusive inclusion. For example, "A and / or B" and "A or B" can both include: "A alone", "B alone", or "A and B", where "A" and "B" can include a single object or multiple objects. For example, "A, B and / or C", "A, B or C" and "A, B and C" can both include: "A alone", "B alone", "C alone", "A and B", "A and C", "B and C", or "A, B and C", where "A", "B" and "C" can include a single object or multiple objects. In addition, " / " in the present disclosure is used to represent the relationship between the associated objects "or". In the present disclosure, "at least one of A or B" and "one or more of A and B" have the same meaning as "A or B" above, "one or more of A, B and C" and "at least one of A, B or C" have the same meaning as "A, B or C" above. "One or more of A, B and C" has the same meaning as "A, B or C" above.

[0106] In the above embodiments, the description of each embodiment has its own focus, and the parts not described or recorded in detail in a certain embodiment can be referred to the relevant description of other embodiments. In addition, the above embodiments can be freely combined as needed.

Claims

1. A pre-processing circuit for a lidar, comprising: a first conversion circuit connected with at least one detector of the lidar, configured to perform a first sampling on an output signal of the at least one detector, outputting first echo data, wherein the first sampling is based on a sampling period; a second conversion circuit connected with the at least one detector, configured to perform a second sampling on the output signal of the at least one detector, outputting second echo data, the second sampling being based on a sampling trigger event, wherein the sampling trigger event comprises the output signal reaching or exceeding a first threshold.

2. The pre-processing circuit of claim 1, wherein, the first echo data is used to determine a first echo parameter, and the second echo data is used to determine a second echo parameter.

3. The pre-processing circuit according to claim 1 or 2, characterized in that, when the lidar is in a first operation mode, the first conversion circuit and the second conversion circuit are both in an active state.

4. The pre-processing circuit according to claim 1 or 2, characterized in that, when the lidar is in a second operation mode, the first conversion circuit or the second conversion circuit is in an active state.

5. The pre-processing circuit of claim 1, wherein, the first conversion circuit comprises: a first sampling circuit connected with the at least one detector, configured to perform the first sampling to determine a first signal, an accumulation circuit connected with the first sampling circuit, configured to determine the first echo data based on the first signal, and a storage circuit configured to store the first echo data.

6. The pre-processing circuit according to claim 1, wherein: the second conversion circuit is coupled with a first reference signal, the first reference signal is used to represent the first threshold, and the second echo data comprises a time when the output signal reaches the first threshold.

7. The pre-processing circuit of claim 6, wherein, the second conversion circuit is further coupled with a second reference signal, the second reference signal is used to represent a second threshold, wherein the second threshold is different from the first threshold.

8. The pre-processing circuit according to claim 6 or 7, characterized in that, the second conversion circuit comprises a first conversion sub-circuit, the first conversion sub-circuit comprises: a comparator comprising a first input end, a second input end and an output end, the first input end is used to couple the output signal of the at least one detector, the second input end is used to couple the reference signal, a second sampling circuit connected with the output end of the comparator, configured to perform the second sampling to determine a second signal, and a decoding circuit connected with the second sampling circuit, configured to output the second echo data based on the second signal.

9. The pre-processing circuit of claim 1, wherein, further comprising: a processing circuit configured to receive at least one of the first echo data or the second echo data, process the at least one of the first echo data or the second echo data, and determine echo information.

10. The pre-processing circuit of claim 9, wherein, the processing circuit is configured to determine a first echo parameter according to the first echo data, and when the first echo parameter is greater than a parameter threshold, determine the echo information using the second echo data; or when the first echo parameter is less than the parameter threshold, determine the echo information using the first echo data; or when the first echo parameter is equal to the parameter threshold, determine the echo information using at least one of the first echo data or the second echo data.

11. A laser receiving apparatus characterized by comprising: A laser radar, the laser receiving device comprising: at least one detector; a pre-processing circuit according to any one of claims 1-10, connected to the at least one detector.

12. A signal processing method characterized by, comprising: receiving first echo data or second echo data; processing at least one of the first echo data or the second echo data to determine echo information, wherein the first echo data is obtained by first sampling an output signal of the at least one detector of the laser radar, the first sampling being based on a sampling period; the second echo signal is obtained by second sampling the output signal of the at least one detector, the second sampling being based on a sampling trigger event, the sampling trigger event comprising the output signal reaching or exceeding a first threshold.

13. The signal processing method of claim 12, wherein, the processing at least one of the first echo data or the second echo data to determine echo information comprises: determining a first echo parameter from the first echo data; when the first echo parameter is greater than a parameter threshold, determining the echo information using the second echo data; or, when the first echo parameter is less than the parameter threshold, determining the echo information using the first echo data; or, when the first echo parameter is equal to the parameter threshold, determining the echo information using one or both of the first echo data or the second echo data.

14. A lidar, comprising: comprising: at least one detector; a pre-processing circuit according to any one of claims 1-10, connected to the at least one detector; a processor connected to the pre-processing circuit, configured to receive data output by the pre-processing circuit and determine point cloud data of the laser radar based on the data output by the pre-processing circuit; wherein the data output by the pre-processing circuit comprises one or more of first echo data, second echo data and echo information.

15. A carrier, characterized by comprising: a main body; the laser radar of claim 14, mounted on the main body.

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