Method, apparatus and storage medium for processing multi-echo signals

Abstract

The application provides a multi-echo signal processing method, device and equipment and a storage medium. The multi-echo signal processing method comprises: obtaining a plurality of echo signals in a preset time period, and then obtaining a first echo signal, a last echo signal, a strongest echo signal and a second strongest echo signal in the plurality of echo signals. Finally, the first echo signal and the second echo signal used for target object ranging are determined from the first echo signal, the last echo signal, the strongest echo signal and the second strongest echo signal. In the application, more accurate and diversified initial data is provided for the subsequent ranging data generation process, and the performance of the laser radar ranging is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser radar, and in particular to a multi-echo signal processing method and device, equipment and a storage medium. BACKGROUND

[0002] Laser radar is a target detection technology. Laser is used as a signal light source, a laser beam is emitted to a target object, and a reflection signal of the target object is collected to obtain the position and speed of the target object. Laser radar has the advantages of high measurement accuracy and strong anti-interference capability, and is widely used in remote sensing, measurement, intelligent driving, robots and other fields.

[0003] In the laser radar ranging technology, when part of the emitted laser beam encounters a measured object, it is reflected, causing the laser radar to receive a first echo beam, and the remaining part continues to move forward and is reflected after encountering other measured objects, causing the laser radar to receive a second echo beam. That is, a transmitted laser beam emitted in a certain transmission period may be reflected twice or more, causing the laser radar to receive multiple echo beams in the corresponding reception period. Therefore, the actual ranging information cannot be obtained only according to one echo beam, resulting in inaccurate laser radar ranging. SUMMARY

[0004] The present application provides a multi-echo signal processing method, device, equipment and storage medium to extract multiple echoes and improve the accuracy of laser radar ranging.

[0005] In a first aspect, the present application provides a multi-echo signal processing method, comprising: obtaining multiple echo signals in a preset time period; determining a first echo signal and a last echo signal in the multiple echo signals according to the sampling time of each echo signal; determining at least two echo signals with the largest amplitude in the multiple echo signals according to the amplitude of each echo signal; determining a strongest echo signal and a second strongest echo signal from the at least two echo signals according to a fixed threshold pulse width of the at least two echo signals; determining a corresponding first echo signal and a second echo signal from the first echo signal, the last echo signal, the strongest echo signal and the second strongest echo signal according to a preset double-echo mode, the first echo signal and the second echo signal being used for target object ranging.

[0006] In some possible embodiments, determining the corresponding first echo signal and the second echo signal comprises: when the preset double-echo mode is a first mode, determining that the strongest echo signal is the first echo signal and the last echo signal is the second echo signal; and when the preset double-echo mode is a second mode, determining that the strongest echo signal is the first echo signal and the second strongest echo signal is the second echo signal.

[0007] In some possible implementations, after determining the corresponding first echo signal and second echo signal, the method further includes: processing the first echo signal to obtain a first ranging value and / or a first pulse width value; processing the second echo signal to obtain a second ranging value and / or a second pulse width value; and using at least one of the first ranging value, the first pulse width value, the second ranging value, and the second pulse width value to compensate for the ranging result of the target object.

[0008] In some possible implementations, after determining the corresponding first echo signal and second echo signal, the method further includes: processing one of the echo signals, the first echo signal and the second echo signal, to obtain a third pulse width value; comparing the third pulse width value with a preset threshold; if the third pulse width value is less than the preset threshold, determining the laser beam flight time based on a first time corresponding to the centroid position of the echo signal waveform; if the third pulse width value is greater than the preset threshold, determining the laser beam flight time based on a second time corresponding to a predetermined leading edge position of the echo signal; and if the third pulse width value is equal to the preset threshold, determining the laser beam flight time based on either the first time or the second time; and determining the distance between the lidar and the target object based on the flight time.

[0009] In some possible implementations, the preset threshold includes any one of the following: a first value representing the pulse width of the echo signal at a critical state between saturation and unsaturation; a second value representing the pulse width when distortion begins to occur at the falling edge of the echo signal, the second value being greater than the first value; and a third value being greater than the first value and less than the second value.

[0010] In a second aspect, this application provides a ranging method for a lidar. The method includes: emitting a laser beam; receiving an echo beam reflected from a target object; determining whether the echo mode corresponding to the current operating mode is a single-echo mode or a dual-echo mode; in dual-echo mode, acquiring multiple echo signals corresponding to the echo beam, and obtaining the ranging result of the target object according to the multi-echo signal processing method as described in the first aspect; in single-echo mode, acquiring a third echo signal corresponding to the echo beam, and obtaining the ranging result of the target object based on the third echo signal.

[0011] In a third aspect, this application provides a processing apparatus for multiple echo signals. The processing apparatus includes: a receiving module for acquiring multiple echo signals within a preset time period; and a processing module for determining the first echo signal and the last echo signal among the multiple echo signals based on the sampling time of each echo signal; for determining at least two echo signals with the largest amplitude among the multiple echo signals based on the amplitude of each echo signal; for determining the strongest echo signal and the second strongest echo signal from the at least two echo signals based on a fixed threshold pulse width of the at least two echo signals; and for determining a corresponding first echo signal and a second echo signal from the first echo signal, the last echo signal, the strongest echo signal, and the second strongest echo signal according to a preset dual-echo mode, wherein the first echo signal and the second echo signal are used for distance measurement of the target object.

[0012] In some possible implementations, the processing module is further configured to determine the strongest echo signal as the first echo signal and the last echo signal as the second echo signal when the preset dual echo mode is the first mode; and to determine the strongest echo signal as the first echo signal and the second strongest echo signal as the second echo signal when the preset dual echo mode is the second mode.

[0013] In some possible implementations, the apparatus further includes: a calculation module for processing the first echo signal to obtain a first ranging value and / or a first pulse width value; for processing the second echo signal to obtain a second ranging value and / or a second pulse width value; and for compensating the ranging result of the target object using at least one of the first ranging value, the first pulse width value, the second ranging value, and the second pulse width value.

[0014] In some possible implementations, the apparatus further includes: a calculation module, configured to process the echo signal for one of the first echo signal and the second echo signal to obtain a third pulse width value; compare the third pulse width value with a preset threshold; if the third pulse width value is less than the preset threshold, determine the laser beam flight time based on a first time corresponding to the centroid position of the echo signal peak; if the third pulse width value is greater than the preset threshold, determine the laser beam flight time based on a second time corresponding to a predetermined leading edge position of the echo signal; and if the third pulse width value is equal to the preset threshold, determine the laser beam flight time based on either the first time or the second time; and determine the distance between the lidar and the target object based on the flight time.

[0015] In some possible implementations, the preset threshold includes any one of the following: a first value representing the pulse width of the echo signal at a critical state between saturation and unsaturation; a second value representing the pulse width when distortion begins to occur at the falling edge of the echo signal, the second value being greater than the first value; and a third value being greater than the first value and less than the second value.

[0016] In a fourth aspect, this application provides a ranging device for a lidar. The ranging device includes: a transmitting module for transmitting a laser beam; an echo receiving module for receiving an echo beam reflected from a target object; a determining module for determining whether the echo mode corresponding to the current operating mode is a single-echo mode or a dual-echo mode; a ranging processing module for, in dual-echo mode, acquiring multiple echo signals corresponding to the echo beam and acquiring a ranging result of the target object according to the multi-echo signal processing method of the first aspect; and for, in single-echo mode, acquiring a third echo signal corresponding to the echo beam and acquiring a ranging result of the target object based on the third echo signal.

[0017] In a fifth aspect, this application provides a lidar, comprising: a memory for storing processor-executable instructions; and a processor; wherein the processor is configured to, when executing the executable instructions, implement methods as described in the first aspect, the second aspect, and possible embodiments thereof.

[0018] In a sixth aspect, this application provides a computer storage medium storing computer-executable instructions, which, when executed by a processor, enable the implementation of methods as described in the first aspect, the second aspect, and their possible embodiments.

[0019] The technical solution provided in this application may include the following beneficial effects:

[0020] In this application, the lidar can acquire multiple echo signals from a laser beam received within a preset time period and process these multiple echo signals. During processing, sampling time information and a fixed threshold pulse width for the echo are incorporated as criteria for judgment. Ultimately, information on the first echo signal, the last echo signal, the strongest echo signal, and the second strongest echo signal are obtained from the multiple echo signals, improving the accuracy and robustness of echo detection. Furthermore, an echo type flag is added after multi-echo signal detection, allowing the echo type to be viewed in the lidar output information. This provides more accurate and diverse initial data for subsequent ranging data generation, offering more effective information for point cloud layer perception algorithms, thereby effectively improving the lidar ranging performance.

[0021] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a lidar in related technologies;

[0023] Figure 2 This is a schematic diagram illustrating the multi-echo generation principle of lidar in related technologies.

[0024] Figure 3 This is a schematic diagram illustrating the implementation process of a multi-echo signal processing method in an embodiment of this application.

[0025] Figure 4 This is a schematic diagram of a multi-echo signal in an embodiment of this application;

[0026] Figure 5 This is a schematic diagram of another multi-echo signal in an embodiment of this application;

[0027] Figure 6 This is a schematic diagram illustrating the implementation process of another multi-echo signal processing method in this application embodiment;

[0028] Figure 7 A schematic diagram illustrating the implementation process of a lidar ranging method provided in this application embodiment;

[0029] Figure 8 This is a schematic diagram illustrating the implementation process of another multi-echo signal processing method in this application embodiment;

[0030] Figure 9 This is a schematic diagram of the structure of a multi-echo signal processing device according to an embodiment of this application;

[0031] Figure 10 This is a schematic diagram of the structure of a lidar ranging device according to an embodiment of this application;

[0032] Figure 11 This is a schematic diagram of the structure of a lidar in an embodiment of this application. Detailed Implementation

[0033] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0034] To illustrate the technical solutions described in the embodiments of this application, specific examples will be used for further explanation below.

[0035] LiDAR is a target detection technology. LiDAR emits a laser beam, which is diffusely reflected when it encounters the target object. The reflected beam is received by a detector, and the target object's characteristics such as distance, azimuth, height, velocity, attitude, and shape are determined based on the emitted and reflected beams.

[0036] The applications of lidar are very broad. Besides its military applications, it is now widely used in everyday life, including but not limited to: autonomous vehicles, autonomous aircraft, 3D printing, virtual reality, augmented reality, and service robots. Taking autonomous driving technology as an example, lidar installed in autonomous vehicles can scan the surrounding environment by rapidly and repeatedly emitting laser beams to obtain point cloud data reflecting the shape, position, and movement of one or more target objects in the environment.

[0037] It should be noted that the aforementioned intelligent driving technologies can refer to technologies such as driverless driving, autonomous driving, and driver assistance systems.

[0038] Figure 1 This is a schematic diagram of the structure of a lidar system in related technologies. See also... Figure 1 As shown, the lidar 10 may include: a light emitting device 101, a light receiving device 102, and a processor 103. The light emitting device 101 and the light receiving device 102 are both connected to the processor 103.

[0039] The connections between the aforementioned devices can be electrical or optical fiber connections. For example, the optical emitting device 101 and the optical receiving device 102 may also include multiple optical devices, and the connections between these optical devices may be spatial optical transmission connections.

[0040] The processor 103 is used to control the transmitting device 101 and the optical receiving device 102 so that the optical transmitting device 101 and the optical receiving device 102 can operate normally. For example, the processor 103 can provide driving voltages to the optical transmitting device 101 and the optical receiving device 102 respectively, and the processor 103 can also provide control signals to the optical transmitting device 101 and the optical receiving device 102.

[0041] For example, processor 103 can be a general-purpose processor, such as a central processing unit (CPU), a network processor (NP), etc.; processor 103 can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0042] The light emitting device 101 also includes a light source (not shown). It is understood that the light source can refer to a laser, and the number of lasers can be one or more. In one embodiment, the laser can be a pulsed laser diode (PLD), a semiconductor laser, a fiber laser, etc. The light source is used to emit a laser beam. For example, the processor 103 can send an emission control signal to the light source, thereby triggering the light source to emit a laser beam.

[0043] Understandably, the aforementioned laser beam can also be referred to as a laser pulse, laser, or emission beam, etc.

[0044] In one embodiment, the aforementioned lidar 10 may further include one or more beam-shaping optics and a beam scanning device (not shown). On one hand, the beam-shaping optics and beam scanning device focus and project a laser beam toward a specific location in the surrounding environment (such as a target object). On the other hand, the beam scanning device and one or more beam-shaping optics guide and focus the returning beam onto a detector. A beam scanning device is employed in the optical path between the beam-shaping optics and the target object. The beam scanning device effectively expands the field of view and increases the sampling density within the lidar's field of view.

[0045] The following is combined with Figure 1 The structure of the lidar shown is briefly described, along with the detection process of the lidar on the object 104 being measured.

[0046] See Figure 1 As shown, the laser beam propagates along the emission direction. When the laser beam encounters the object being measured 104, it is reflected from the surface of the object 104, and the reflected beam is received by the laser radar's optical receiving device 102. Here, the laser beam reflected back by the object 104 can be called the echo beam. Figure 1 The laser beam and echo beam are indicated by solid lines.

[0047] After receiving the echo beam, the optical receiver 102 performs photoelectric conversion on the echo beam, that is, converts the echo beam into an electrical signal. The optical receiver 102 outputs the electrical signal corresponding to the echo beam to the processor 103. The processor 103 can obtain point cloud data such as the shape, position, and motion of the object under test 104 based on the electrical signal of the echo beam.

[0048] Furthermore, the echo beam received by the aforementioned optical receiving device 102 is typically a single beam, meaning that one laser beam is reflected once by the object being measured 104 to form one echo beam. However, not all echo beams are single beams. In actual use of lidar, there are also cases where one emitted laser beam is reflected by multiple objects to form multiple echo beams. Figure 2This is a schematic diagram illustrating the multi-echo generation principle of lidar in related technologies, such as... Figure 2 As shown. When the lidar performs ranging, the laser emitter 20 emits a laser beam, a portion of which ( Figure 2 When region a in the image encounters the target object 21, it is reflected, while the remaining part ( Figure 2 The laser beam (in region b) will continue forward, encountering the target object 22 and then being reflected. This results in the lidar receiving an echo from the target object 21 once, and then another echo from the target object 22. Essentially, a single emitted laser beam may be reflected two or more times, causing the lidar to receive multiple echo beams corresponding to a single emitted laser beam.

[0049] In related technologies, lidar defaults to single-echo mode, meaning it only receives and processes the echo beam reflected from the target object, such as the first echo or the strongest echo. Therefore, the lidar will inevitably fail to obtain the echo beam that most accurately reflects the information of the target object, thus affecting the accuracy of lidar ranging.

[0050] To address the aforementioned issues, this application provides a method for processing multi-echo signals. This method can be applied to the aforementioned lidar to process multiple echoes, providing more accurate and diverse initial data for the subsequent ranging data generation process, thereby improving the ranging performance of the lidar. Figure 3 This is a schematic diagram illustrating the implementation flow of a multi-echo signal processing method according to an embodiment of this application. See also... Figure 3 As shown, the processing method for the multi-echo signal may include S301 to S305.

[0051] S301 acquires multiple echo signals within a preset time period.

[0052] Understandably, lidar can continuously receive echo beams within a preset time period, thereby obtaining multiple echo signals converted from the echo beams.

[0053] The echo signal can be an electrical signal obtained by the optical receiving device 102 after receiving the echo beam and performing photoelectric conversion on the echo beam. That is, the echo signal can be a voltage or current that varies with time. For ease of explanation, the following embodiments will use a voltage that varies with time as an example for the echo signal. Furthermore, since the echo signal is a voltage that varies with time, the echo signal can be described as a function of time, and its waveform can be plotted.

[0054] For example, Figure 4 This is a schematic diagram of a multi-echo signal in an embodiment of this application. See also... Figure 4As shown, the X-axis represents time, and the Y-axis represents the relative intensity of the voltage. Based on the relationship between the received voltage and time, the lidar can plot the peaks of the echo signal. For example... Figure 4 The peaks A, B, and C shown represent echo signals A, B, and C received by the lidar, respectively.

[0055] In this embodiment, the preset time period can be understood as the sampling period of the lidar, the single-point measurement period, etc., or it can be understood as a time period set according to the ranging requirements. For example, the preset time period can be 100ns, 500ns, 700ns, etc. Of course, other situations may exist, and this embodiment does not specifically limit them.

[0056] S302, based on the sampling time of each echo signal, determine the first echo signal and the last echo signal among multiple echo signals.

[0057] The first echo signal is the first echo signal within the preset time period, and the last echo signal is the last echo signal within the preset time period.

[0058] Understandably, by executing S301, the lidar can obtain multiple echo signals within a preset time period. Subsequently, by executing S302, the lidar can plot the peak corresponding to each echo signal based on the relationship between the voltage value and time of the echo signal. Simultaneously, the lidar can select any moment within the time range corresponding to the peak as the sampling time of the echo signal. Finally, by comparing the sampling times of the echo signals, the lidar can determine the first and last echo signals among the multiple echo signals.

[0059] For example, such as Figure 4 As shown, along the positive X-axis (the direction of increasing time), peak A is to the left of peak B, meaning the time range corresponding to peak A is earlier than the time range corresponding to peak B. Therefore, the sampling time of echo signal A is earlier than the sampling time of echo signal B. And so on, we can obtain... Figure 4 The first echo signal is echo signal A, and the last echo signal is echo signal C.

[0060] S303, based on the amplitude of each echo signal, determine at least two echo signals with the largest amplitude among multiple echo signals.

[0061] Among them, the maximum amplitude can be the maximum value of the voltage or current value of the echo signal, that is, the highest point of the wave peak corresponding to the echo signal.

[0062] Understandably, a lidar system can obtain the highest point of the peak corresponding to each echo signal. Furthermore, by comparing the peak value (or amplitude) corresponding to the highest point of each peak, a lidar system can identify at least two peaks with the same maximum value. The echo signals corresponding to these at least two peaks are the at least two echo signals with the largest amplitude.

[0063] For example, Figure 5 This is a schematic diagram of another multi-echo signal in an embodiment of this application. See [link / reference] Figure 5 As shown in the diagram, the X-axis represents time, and the Y-axis represents the relative intensity of the voltage. The lidar receives four echo signals within a preset time: echo signal A, echo signal B, echo signal C, and echo signal D. Echo signals B and D both have the maximum amplitude T1, therefore echo signals B and D are the echo signals with the largest amplitude among the multiple echo signals.

[0064] S304, determine the strongest echo signal and the second strongest echo signal from at least two echo signals based on a fixed threshold pulse width of at least two echo signals.

[0065] The strongest echo signal is the echo signal with the largest amplitude within the preset time period, and the second strongest echo signal is the echo signal with the second largest amplitude within the preset time period.

[0066] Understandably, by executing S303, the lidar can obtain at least two echo signals with the largest amplitudes from multiple echo signals. Subsequently, the lidar executes S304 to obtain the fixed threshold pulse width of the echo signals obtained in S303. Finally, the lidar compares the fixed threshold pulse widths of the at least two echo signals, determining the echo signal with the largest fixed threshold pulse width as the strongest echo signal, and the echo signal with the second largest fixed threshold pulse width as the second strongest echo signal.

[0067] In some possible implementations, a lidar can obtain a fixed threshold pulse width from the peaks of the echo signal. Understandably, the lidar can pre-set a threshold voltage, identify two position points from the peaks corresponding to the echo beam where the voltage equals the threshold voltage, and calculate the time difference between these two position points. This difference is the fixed threshold pulse width of the echo signal.

[0068] For example, such as Figure 5 As shown, the lidar can be set to a fixed threshold voltage T2. The two points on the peak of the echo signal B that equal the threshold voltage T2 are b1 and b2, and the two points on the peak of the echo signal D that equal the threshold voltage T2 are d1 and d2. b2 - b1 = the fixed threshold voltage of echo signal B, and d2 - d1 = the fixed threshold voltage of echo signal D.

[0069] It should be noted that the lidar, when executing S303, obtains multiple echo signals with equal amplitude. When the peak amplitudes are equal, the larger the fixed threshold pulse width, the larger the area integral of the corresponding peak, meaning the stronger the echo signal. Therefore, the echo signal with the largest fixed threshold pulse width is necessarily the strongest echo signal.

[0070] S305, according to the preset dual-echo mode, determines the corresponding first echo signal and second echo signal from the first echo signal, the last echo signal, the strongest echo signal and the second strongest echo signal.

[0071] It should be noted that the determination of the first and last echo signals is related to the reception time of the echo signals, while the determination of the strongest and second strongest echo signals is related to the amplitude of the echo signals and the fixed threshold pulse width. Therefore, in some cases, an echo signal can be the first echo signal, the strongest echo signal, or the second strongest echo signal; similarly, an echo signal can be the last echo signal, the strongest echo signal, or the second strongest echo signal.

[0072] Understandably, by executing steps S301 to S304, the lidar can obtain the first echo signal, the last echo signal, the strongest echo signal, and the second strongest echo signal within a preset time period. Subsequently, the lidar executes step S305, and based on the preset dual-echo mode, determines the first echo signal and the second echo signal corresponding to the dual-echo mode from the obtained first echo signal, last echo signal, strongest echo signal, and second strongest echo signal.

[0073] The first and second echo signals are used for ranging the target object. That is, the data from the first and second echo signals are used for generating and processing subsequent ranging data by the lidar. Furthermore, the lidar can obtain echo information from the first and second echoes and identify the echo type in the frame format when outputting the required echo information. This echo type flag can provide more effective information for the point cloud layer perception algorithm.

[0074] In some possible implementations, the lidar determines the corresponding first echo signal and second echo signal, including: when the preset dual echo mode is the first mode, determining the strongest echo signal as the first echo signal and the last echo signal as the second echo signal; when the preset dual echo mode is the second mode, determining the strongest echo signal as the first echo signal and the second strongest echo signal as the second echo signal.

[0075] Understandably, a lidar can determine the first and second echo signals to be output based on whether the dual-echo mode is the first or the second mode.

[0076] The first and second modes correspond to different usage requirements of the LiDAR. These requirements can be set based on practical experience. For example, the first and second modes can correspond to the LiDAR's usage needs in different external environments. When there are highly reflective objects in the external environment, the LiDAR can use the first mode; when there are retroreflective objects in the external environment, the LiDAR can use the second mode.

[0077] The processing method for the above-mentioned multi-echo signals will be illustrated below with specific examples.

[0078] Assuming, Figure 5 For a schematic diagram of a multi-echo signal in a specific example, see [link / reference]. Figure 5 As shown, the lidar receives four echo signals within a preset time: echo signal A, echo signal B, echo signal C, and echo signal D.

[0079] Step 1: The lidar extracts the first echo signal and the last echo signal (such as echo signal A and echo signal D) from echo signal A, echo signal B, echo signal C and echo signal D according to the reception time.

[0080] Step 2: The lidar extracts at least two echo signals (such as echo signal B and echo signal D) with the largest amplitude from echo signal A, echo signal B, echo signal C, and echo signal D.

[0081] Step 3: The lidar extracts the strongest echo signal and the second strongest echo signal (such as echo signal D and echo signal B) from echo signal B and echo signal D according to a fixed threshold value.

[0082] Step 4: The lidar outputs echo signal D according to the strongest echo signal (e.g., echo signal D) and the last echo signal (e.g., echo signal D) corresponding to the first mode.

[0083] In this embodiment, the lidar can acquire multiple echo signals from a laser beam received within a preset time period, and process these multiple echo signals to obtain information on the first echo signal, the last echo signal, the strongest echo signal, and the second strongest echo signal. This embodiment provides more accurate and diverse initial data for the subsequent ranging data generation process, thereby effectively improving the ranging performance of the lidar.

[0084] As described above, the lidar can determine the amplitude and fixed threshold pulse width of multiple echo signals, as well as the first and second echo signals that meet the preset mode requirements, through steps S301 to S305. After steps S301 to S305, the lidar can also use the aforementioned first and second echo signals for lidar ranging.

[0085] In some possible implementations, Figure 6 This is a schematic diagram illustrating the implementation flow of another multi-echo signal processing method in an embodiment of this application. Figure 6 As shown, the lidar can also use the aforementioned first echo signal and second echo signal for lidar ranging. That is, the processing method of the multi-echo signal can also include S601 to S603, which are executed after S301 to S305.

[0086] S601, process the first echo signal to obtain the first ranging value and / or the first pulse width value.

[0087] Understandably, after obtaining the first echo signal through S301 to S306, the lidar can process the data of the first echo signal and calculate the ranging value and / or the first pulse width value corresponding to the first echo signal based on the data of the first echo.

[0088] In one embodiment, the method by which the lidar calculates the first ranging value based on the data of the first echo can be set according to actual needs. For example, firstly, the lidar can determine the peak of the first echo based on the data, and then determine the centroid corresponding to that peak. Finally, the lidar uses the value of the centroid to calculate the ranging value corresponding to the first echo signal using the centroid ranging method.

[0089] In one embodiment, the first pulse width value can be the pulse width of the first echo signal at any peak height (i.e., voltage value). For example, the lidar can set the first pulse width value to the full width at half maximum (FWHM) of the first echo signal. Here, FWHM refers to the peak width at half the peak height, that is, the distance between two points where a straight line parallel to the base of the peak intersects the two sides of the peak.

[0090] S602, process the second echo signal to obtain the second ranging value and / or the second pulse width value.

[0091] Understandably, after obtaining the second echo signal through S301 to S306, the lidar can process the data of the second echo signal and calculate the ranging value and / or the second pulse width value corresponding to the second echo signal based on the data of the second echo.

[0092] The calculation methods for the second ranging value and the second pulse width value can refer to the above description of the first ranging value and the first pulse width value.

[0093] S603, using at least one of the first ranging value, the first pulse width value, the second ranging value, and the second pulse width value, to compensate for the ranging result of the target object being measured.

[0094] Understandably, the lidar can obtain a first ranging value and a first pulse width value calculated based on the first echo signal, and a second ranging value and a second pulse width value calculated based on the second echo signal through steps S601 to S602. Subsequently, the lidar executes step S603, using at least one of the aforementioned first ranging value, first pulse width value, second ranging value, and second pulse width value, that is, using the information obtained from the first echo signal and the second echo signal to compensate for the ranging result of the target object.

[0095] In some possible implementations, the lidar can obtain a first ranging value and a second ranging value through the embodiments of this application. Alternatively, the lidar can obtain the ranging result using a different ranging method than those described in the embodiments of this application. Finally, the lidar uses the first and second ranging values ​​to compensate for the ranging result.

[0096] For example, suppose the lidar obtains a ranging result of 5m through the original echo signal processing method, while the first ranging value and the second ranging value are 7m and 8m respectively. Then the lidar can compensate for 5m based on 7m and 8m to obtain a more accurate ranging result.

[0097] In some possible implementations, the method by which the lidar uses a first pulse width value and a second pulse width value for ranging compensation can be set according to actual needs, and this application embodiment does not specifically limit this. For example, the first and second pulse width values ​​can compensate for the centroid of the echo signal peak. The compensated centroid can be used to calculate the ranging result, thus achieving compensation of the ranging result by the first and second pulse width values. Alternatively, the first and second pulse width values ​​can compensate for the start time of the echo signal peak (equivalent to the echo signal reception time). The compensated start time can be used to calculate the ranging result, thus achieving compensation of the ranging result by the first and second pulse width values.

[0098] In this embodiment, the lidar can obtain the first echo signal and the second echo signal required for ranging from the first echo signal, the last echo signal, the strongest echo signal, and the second strongest echo signal. The first echo signal and the second echo signal are then processed to obtain a first ranging value, a first pulse width value, a second ranging value, and a second pulse width value. By using at least one of the first ranging value, the first pulse width value, the second ranging value, and the second pulse width value, compensation is made for the ranging result of the target object, thus achieving compensation for the lidar ranging result.

[0099] In some possible implementations, Figure 8 This is a schematic diagram illustrating the implementation flow of another multi-echo signal processing method according to an embodiment of this application. Figure 8As shown, in addition to the echo processing methods described in S601 to S603 above, the lidar can also process the echo signal (such as at least one of the first echo signal and the second echo signal mentioned above) and use other methods to achieve lidar ranging. S801 to S806 may also be included after S301 to S305.

[0100] The method begins at S801, where the lidar can receive echo signals. As mentioned earlier, the echo signal refers to the signal obtained by photoelectric conversion, multi-stage amplification, and analog-to-digital conversion of the echo beam. The lidar can, for example, receive echo signals from... Figure 1 The optical receiving device 102 shown receives the echo signal. It should be understood that the echo signal (such as the first echo signal or the second echo signal) can be obtained by performing any known preprocessing on the echo beam, as long as the echo signal is suitable for an ADC-based ranging method.

[0101] Next, we proceed to S802. In S802, the lidar can determine the pulse width, centroid time, and leading-edge time of the echo signal. More specifically, the lidar can first determine the echo interval of the echo signal, and then determine the full width at half maximum (FWHM) of the echo signal within the echo interval as the pulse width. For example, the interval containing the sampling points among multiple sampling points of the echo signal that are greater than a preset value can be determined as the echo interval. Other known methods can be used to determine the echo interval. Any known signal processing method can be used to determine the FWHM of the echo signal within the echo interval; this embodiment does not limit this.

[0102] It should be understood that the center of gravity time and the leading edge time can be determined in S802, or the center of gravity time can be determined in S804 and the leading edge time can be determined in S806.

[0103] Next, we proceed to S803. In S803, the lidar can determine whether the pulse width determined in S802 is less than a preset threshold.

[0104] If the determined pulse width is less than a preset threshold, proceed to S804. In S804, the lidar can determine the laser beam flight time based on the centroid time. More specifically, the lidar calculates the time difference between the centroid time of the echo signal and the first emission time of the laser beam as the laser beam flight time. In some embodiments, the first emission time may be the time corresponding to the centroid position of the laser beam waveform. In other embodiments, the first emission time may be the sum of the following two items: the first item is the transmission time of the trigger signal used to trigger the lidar to emit the laser beam, and the second item is the delay time between the transmission time and the time the lidar emits the laser beam. In still other embodiments, the first emission time may be a preset fixed time. Various known methods can be used to determine the first emission time here. This application embodiment does not limit this.

[0105] If the determined pulse width is greater than or equal to a preset threshold, the process proceeds to S806, where the lidar determines the flight time of the laser beam based on the leading edge time. More specifically, the lidar calculates the time difference between the leading edge time of the echo signal and a second emission time relating to the laser beam's emission as the laser beam's flight time. The second emission time may be the same as or different from the first emission time. In some embodiments, the second emission time may correspond to the time when the laser beam is at its leading edge position at half-peak height. In this case, the second emission time is different from the first emission time. In other embodiments, the second emission time may be the sum of two items: the first item is the transmission time of the trigger signal used to trigger the lidar to emit the laser beam, and the second item is the delay time between that transmission time and the time when the lidar emits the laser beam. In this case, the second emission time is the same as the first emission time. In still other embodiments, the second emission time may be a preset fixed time. In this case, the second emission time is the same as the first emission time. Various known methods can be used to determine the second emission time. This application does not limit this.

[0106] The following describes how to determine the preset threshold as described above. In some embodiments, a first value W1, representing the pulse width (i.e., the width of the peak) of the echo signal at the critical state between saturation and unsaturation, can be determined as the preset threshold. In other embodiments, a second value W2, representing the pulse width at which distortion begins to occur on the falling edge of the echo signal, can be determined as the preset threshold, and the second value W2 is greater than the first value W1. In still other embodiments, a third value W3, greater than the first value W1 and less than the second value W2, can be determined as the preset threshold.

[0107] When the echo signal is unsaturated, jitter occurs at the leading edge. When the echo signal is saturated and the pulse width is too wide, distortion occurs at the falling edge. By setting the preset threshold to the aforementioned first value W1, the laser beam flight time is determined based on the centroid time when the echo signal is unsaturated, and based on the leading edge time when the echo signal is saturated. Alternatively, by setting the preset threshold to the aforementioned second value W2, the laser beam flight time is determined based on the centroid time when the falling edge of the echo signal has not yet distorted, and based on the leading edge time when the falling edge of the echo signal has distorted. Alternatively, by setting the preset threshold to the aforementioned third value W3, it is ensured that the laser beam flight time is determined based on the centroid time when the echo signal is unsaturated, and based on the leading edge time when the falling edge of the echo signal has distorted. Therefore, the laser beam flight time can be determined more accurately, and thus the distance between the lidar and the target object can be determined more accurately.

[0108] It should be understood that the preset threshold depends on the waveform parameters of the emitted laser beam. The preset threshold may differ for emitted laser beams of different heights and / or widths. This preset threshold can be determined, for example, through experimental methods.

[0109] It should be understood that, Figure 8 In this embodiment, when the pulse width equals a preset threshold, the laser beam flight time is determined based on the leading edge time. However, the embodiments of this application are not limited to this. Alternatively, when the pulse width equals the preset threshold, the laser beam flight time can be determined based on the centroid time. In other words, when the pulse width equals the preset threshold, the laser beam flight time can be determined based on either the centroid time or the leading edge time.

[0110] Next, we move to S805. In S805, the lidar can determine the distance between the lidar and the target object based on the laser beam flight time determined in S804 or S806.

[0111] More specifically, the distance R between the lidar and the target object can be calculated according to the following formula (1).

[0112] R = c × t / (2 × n) (1)

[0113] Where c is the speed of light, n is the refractive index of light in air (n is usually assumed to be 1), and t represents the time of flight of the laser beam. It should be understood that other known methods can be used to determine the distance based on the time of flight.

[0114] In some possible implementations, a step (not shown) for fitting compensation of the determined laser beam flight time may be included before S805. For example, the flight time can be fitted and compensated based on the amplitude of the echo signal, the pulse width, the temperature of the environment in which the lidar is located, etc., so that the flight time calculated for echo signals with different intensities corresponding to the same distance is substantially the same. Any known fitting compensation algorithm can be used for compensation.

[0115] As described above, the lidar can set a preset threshold and compare it with the third pulse width value to obtain a flight time that more closely matches the first echo signal, thus increasing the accuracy of lidar ranging. Similarly, the lidar can also use this method to obtain the flight time of the second echo signal, and then obtain the ranging distance calculated from the second echo. Furthermore, the lidar can also summarize the ranging results of the first and second echo signals to obtain a more accurate ranging value. In addition, the ranging method in S801 to S806 can also be applied to S601 to S603 to obtain the first and second ranging values. The specific implementation process can be referred to the description in the above embodiments, and will not be repeated here.

[0116] In this embodiment, the lidar analyzes and processes multiple echo signals received within a preset time period to identify the first and second echo signals. Based on these signals, a pulse width value is obtained, and by comparing the pulse width value with a preset threshold, the flight time for ranging is determined. Finally, the ranging result is calculated. This process effectively improves the ranging accuracy and enhances the ranging performance of the lidar.

[0117] In some possible implementations, after the lidar acquires multiple echo signals within a preset time period, it determines the echo mode corresponding to the current working mode. When the current working mode is determined to be a dual-echo mode, the echo signal processing can be as described in the embodiments of S302 to S305, S601 to S603 and S801 to S803 above.

[0118] In some possible implementations, when the lidar determines that the current operating mode is single-echo mode, the processing method for the multi-echo signal further includes: determining the third echo signal with the largest amplitude among the multiple echo signals based on the amplitude of each echo signal.

[0119] Understandably, the third echo signal is used for ranging the target object. In one embodiment, the lidar can compensate for the ranging result of the target object based on the third echo signal. This method is the same as the method by which the lidar compensates for the ranging result of the target object based on the first and second echo signals. That is, the lidar can process the third echo signal to obtain a fourth ranging value and / or a fourth pulse width value. The lidar uses the fourth ranging value and / or the fourth pulse width value to compensate for the ranging result of the target object. The specific implementation process can be referred to the description of the embodiments in S601 to S603.

[0120] In another embodiment, the lidar can determine the flight time for ranging based on the comparison between the pulse width value of the third echo signal and a preset threshold, and finally calculate the ranging result. This method is the same as the method by which the lidar measures the distance to the target object based on the first and second echo signals. The specific implementation process can be referred to the description of the embodiments in S801 to S803.

[0121] In this embodiment of the application, by analyzing and processing multiple echo signals within a preset time period of the lidar, the third echo signal among the multiple echo signals can be determined. Then, the ranging value and pulse width value can be obtained based on the third echo signal, so as to provide more accurate and diversified initial data for the subsequent ranging data generation process, thereby improving the ranging performance of the lidar.

[0122] Based on the same inventive concept, this application also provides a ranging method for lidar, applied to lidar, the method comprising:

[0123] Step 1: Firing a laser beam.

[0124] Step 2: Receive the echo beam of the laser beam reflected by the target object.

[0125] Understandably, when the laser beam emitted by the lidar hits multiple target objects, it can generate multiple echo signals, and all of these echo signals can be received.

[0126] Step 3: Determine the echo mode corresponding to the current working mode.

[0127] Understandably, lidar can determine whether the current operating mode is single-echo or dual-echo.

[0128] Step four: In dual-echo mode, according to methods S301 to S305, acquire multiple echo signals corresponding to the echo beam, process the multiple echo signals corresponding to the echo beam to obtain the first echo signal and the second echo signal. Then, according to methods S601 to S603 and S801 to S806, acquire the ranging result of the target object.

[0129] Understandably, a lidar can receive and process multiple echo signals to obtain the ranging result of the target object. Specific processing methods can be found in the detailed descriptions of the embodiments in S301 to S305, S601 to S603, and S801 to S806, which will not be repeated here for the sake of brevity.

[0130] Step 5: In single-echo mode, acquire a third echo signal corresponding to the echo beam, and obtain the distance measurement result of the target object based on the third echo signal.

[0131] In some possible implementations, when the lidar determines that the current operating mode is single-echo mode, the lidar ranging method further includes: determining the third echo signal with the largest amplitude among multiple echo signals based on the amplitude of each echo signal.

[0132] Understandably, the third echo signal is used for ranging the target object. In one embodiment, the lidar can compensate for the ranging result of the target object based on the third echo signal. This method is the same as the method by which the lidar compensates for the ranging result of the target object based on the first and second echo signals. That is, the lidar can process the third echo signal to obtain a fourth ranging value and / or a fourth pulse width value. The lidar uses the fourth ranging value and / or the fourth pulse width value to compensate for the ranging result of the target object. The specific implementation process can be referred to the description of the embodiments in S601 to S603.

[0133] In another embodiment, the lidar can determine the flight time for ranging based on a comparison between the pulse width value of the third echo signal and a preset threshold, and finally calculate the ranging result. This method is the same as the method by which lidar measures the distance to the target object based on the echo signal. The specific implementation process can be referred to the descriptions in embodiments S801 to S806.

[0134] In this embodiment, the lidar can accurately determine the distance between the lidar and the target object by receiving and processing multiple echo signals reflected from the laser beam. Furthermore, multiple echo signals can be used to compensate for the ranging distance, further improving the accuracy of the ranging.

[0135] The following example will be used to explain the ranging method of the above-mentioned lidar in detail.

[0136] Figure 7 This is a schematic diagram illustrating the implementation process of a lidar ranging method provided in an embodiment of this application, as shown below. Figure 7 As shown, the following is the processing procedure of the distance measurement method:

[0137] S700, begin.

[0138] S701: After the raw data of the multi-echo signal is acquired, it is preprocessed (e.g., DC component is calculated, noise floor is measured), and then it enters S702.

[0139] S702, perform constant false alarm detection on multi-echo signals (for example, set the corresponding detection threshold according to the noise level and false alarm rate requirements, and remove false points caused by noise based on whether the points that have exceeded the threshold appear more than 3 times in a row, and retain other detection points), and then proceed to S703.

[0140] S703 determines whether the lidar is in dual-echo mode. If yes, proceed to S704; otherwise, proceed to S711.

[0141] S704, the lidar is in dual-echo mode, extracting four valid echoes within a preset time period, and then proceeding to S705.

[0142] S705 identifies the echo type based on amplitude, sampling time, and fixed threshold pulse width, and then proceeds to S706.

[0143] S706, determine the echo type (including first echo, strongest echo, second strongest echo, and last echo), and proceed to S707 after completion.

[0144] S707, determine the first and second echoes according to the first or second mode of the dual echo mode, and then proceed to S708.

[0145] S708, based on the first echo and the second echo, calculate the first ranging value, the first pulse width value, the second ranging value, the second pulse width value, and the first ranging distance, and then proceed to S709.

[0146] S709: Obtain the echo information of the first and second echoes based on the first and second echoes in S707, output the required echo information and mark the echo type in the frame format, and then proceed to S710.

[0147] S710, process the first echo signal and / or the second echo signal, use the ranging value and pulse width value to perform ranging compensation on the first ranging distance or the second ranging distance, and then proceed to S713.

[0148] S711, the lidar is in single-echo mode, the location and amplitude of the strongest amplitude echo are extracted, and then proceed to S712.

[0149] S712, based on the strongest echo mentioned above, calculate the fourth ranging value, the fourth pulse width value, and the second ranging distance, and then proceed to S710.

[0150] S713, End.

[0151] In this embodiment, the lidar can acquire multiple echo signals from a laser beam received within a preset time period and analyze these multiple echo signals. During the analysis, sampling time information and a fixed threshold pulse width for the echo are incorporated as criteria for judgment. Ultimately, information on the first echo signal, the last echo signal, the strongest echo signal, and the second strongest echo signal among the multiple echo signals is obtained, improving the accuracy and robustness of echo detection. Furthermore, an echo type flag is added after multiple echo signal detection, allowing the echo type to be viewed in the lidar output information. This provides more accurate and diverse initial data for subsequent ranging data generation, offering more effective information for point cloud layer perception algorithms, thereby effectively improving the lidar ranging performance.

[0152] Based on the same inventive concept, this application also provides a multi-echo signal processing apparatus. This apparatus can be a chip or system-on-a-chip in a lidar system, or a functional module in the lidar system used to implement the multi-echo signal processing methods described in the various embodiments above. This multi-echo signal processing apparatus can implement the functions performed by the lidar in the various embodiments of the multi-echo signal processing methods described above. These functions can be implemented by hardware executing corresponding software. This hardware or software includes one or more modules corresponding to the aforementioned functions.

[0153] Figure 9 This is a schematic diagram of the structure of a multi-echo signal processing device according to an embodiment of this application. See also... Figure 9 As shown, the multi-echo signal processing device 900 includes: a receiving module 901, used to acquire multiple echo signals within a preset time period; and a processing module 902, used to: determine the first echo signal and the last echo signal among the multiple echo signals based on the sampling time of each echo signal; determine at least two echo signals with the largest amplitude among the multiple echo signals based on the amplitude of each echo signal; determine the strongest echo signal and the second strongest echo signal from the at least two echo signals based on a fixed threshold pulse width of the at least two echo signals; and determine the corresponding first echo signal and second echo signal from the first echo signal, the last echo signal, the strongest echo signal, and the second strongest echo signal according to a preset dual-echo mode, wherein the first echo signal and the second echo signal are used for distance measurement of the target object.

[0154] In some possible implementations, the processing module 902 is further configured to determine the strongest echo signal as the first echo signal and the last echo signal as the second echo signal when the preset dual echo mode is the first mode; and to determine the strongest echo signal as the first echo signal and the second strongest echo signal as the second echo signal when the preset dual echo mode is the second mode.

[0155] In some possible implementations, the multi-echo signal processing device 900 further includes: a calculation module 903, configured to process the first echo signal to obtain a first ranging value and / or a first pulse width value; to process the second echo signal to obtain a second ranging value and / or a second pulse width value; and to compensate for the ranging result of the target object using at least one of the first ranging value, the first pulse width value, the second ranging value, and the second pulse width value.

[0156] In some possible implementations, the multi-echo signal processing device 900 further includes: a calculation module 903, which processes one of the echo signals, the first echo signal and the second echo signal, to obtain a third pulse width value; compares the third pulse width value with a preset threshold; if the third pulse width value is less than the preset threshold, determines the laser beam flight time based on a first time corresponding to the centroid position of the waveform of the echo signal; if the third pulse width value is greater than the preset threshold, determines the laser beam flight time based on a second time corresponding to a predetermined leading edge position of the echo signal; and if the third pulse width value is equal to the preset threshold, determines the laser beam flight time based on either the first time or the second time; and determines the distance between the lidar and the target object based on the flight time.

[0157] In some possible implementations, the preset threshold includes any one of the following: a first value representing the pulse width of the echo signal at a critical state between saturation and unsaturation; a second value representing the pulse width when distortion begins to occur at the falling edge of the echo signal, the second value being greater than the first value; and a third value being greater than the first value and less than the second value.

[0158] In some possible implementations, the multi-echo signal processing device 900 further includes: a determination module 904, used to determine that the echo mode corresponding to the current operating mode is a dual-echo mode.

[0159] In some possible implementations, the determining module 904 is further configured to determine that the echo mode corresponding to the current working mode is a single echo mode; the processing module 902 is further configured to determine the third echo signal with the largest amplitude among multiple echo signals based on the amplitude of each echo signal, and the third echo signal is used for distance measurement of the target object.

[0160] It should be noted that the specific implementation process of the receiving module 901, processing module 902, calculation module 903, and determination module 904 can be found in [reference needed]. Figures 1 to 8 For the sake of brevity, the detailed description of the embodiments will not be repeated here.

[0161] The receiving module 901 mentioned in this embodiment can be a receiver, such as... Figure 1The optical receiving device 102; processing module 902, calculation module 903, and determination module 904 can be one or more processors, such as Figure 1 The processor 103 in the middle.

[0162] Based on the same inventive concept, this application also provides a ranging device for a lidar. This ranging device can be a chip or system-on-a-chip in the lidar, or a functional module in the lidar used to implement the ranging methods described in the various embodiments above. This ranging device can implement the functions performed by the lidar in the various embodiments of the lidar ranging methods described above. These functions can be implemented by hardware executing corresponding software. This hardware or software includes one or more modules corresponding to the above functions.

[0163] Figure 10 This is a schematic diagram of the structure of a lidar ranging device according to an embodiment of this application. See also... Figure 10 As shown, the ranging device 1000 includes: a transmitting module 1001 for transmitting a laser beam; an echo receiving module 1002 for receiving the echo beam reflected by the laser beam from the target object; a determining module 1003 for determining whether the echo mode corresponding to the current working mode is a single-echo mode or a dual-echo mode; a ranging processing module 1004 for acquiring multiple echo signals corresponding to the echo beam in dual-echo mode, and acquiring the ranging result of the target object according to the above-mentioned multi-echo signal processing method; and for acquiring a third echo signal corresponding to the echo beam in single-echo mode, and acquiring the ranging result of the target object according to the third echo signal.

[0164] It should be noted that the specific implementation process of the transmitting module 1001, the echo receiving module 1002, the determining module 1003, and the ranging processing module 1004 can be found in [reference needed]. Figures 1 to 8 For the sake of brevity, the detailed description of the embodiments will not be repeated here.

[0165] The transmitting module 1001 mentioned in this application embodiment can be a transmitting interface, transmitting circuit, or transmitter, etc. Figure 1 The optical transmitting device 101 and the echo receiving module 1002 can be a receiving interface, receiving circuit, or receiver, etc. Figure 1 The optical receiving device 102; the determining module 1003 and the ranging processing module 1004 can be one or more processors, such as... Figure 1 The processor 103 in the middle.

[0166] Based on the same inventive concept, this disclosure provides a lidar, which can be the lidar described in one or more of the above embodiments. Figure 11This is a schematic diagram of the structure of a lidar according to an embodiment of this application. See also... Figure 11 As shown, the lidar 1100 can use general-purpose computer hardware, including a processor 1101 and a memory 1102.

[0167] In some possible implementations, at least one processor can constitute any physical device having circuitry that performs logical operations on one or more inputs. For example, at least one processor may include one or more integrated circuits (ICs), including application-specific integrated circuits (ASICs), microchips, microcontrollers, microprocessors, all or part of a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a field-programmable gate array (FPGA), or other circuitry suitable for executing instructions or performing logical operations. Instructions executed by at least one processor may, for example, be preloaded into memory integrated with or embedded in the controller, or may be stored in separate memory. Memory may include random access memory (RAM), read-only memory (ROM), hard disk, optical disk, magnetic media, flash memory, other permanent, fixed, or volatile memory, or any other mechanism capable of storing instructions. In some embodiments, at least one processor may include more than one processor. Each processor may have a similar architecture, or processors may have different configurations that are electrically connected or disconnected from each other. For example, processors may be separate circuits or integrated into a single circuit. When more than one processor is used, the processors may be configured to operate independently or collaboratively. Processors can be coupled electrically, magnetically, optically, acoustically, mechanically, or through other means that allow them to interact.

[0168] Based on the same inventive concept, the present invention also provides a computer-readable storage medium storing computer instructions thereon, which are executed by a processor using the steps of the above-described multi-echo signal processing method. For specific implementation processes and functions, please refer to the related embodiments described above.

[0169] Those skilled in the art will understand that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0170] The embodiments described above are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for processing multi-echo signals, characterized in that, include: Multiple echo signals are obtained within a preset time period; Based on the sampling time of each echo signal, determine the first echo signal and the last echo signal among the plurality of echo signals; Based on the amplitude of each echo signal, determine at least two echo signals with the largest amplitude among the plurality of echo signals; Based on the fixed threshold pulse width of the at least two echo signals, determine the strongest echo signal and the second strongest echo signal from the at least two echo signals; According to the preset dual-echo mode, the corresponding first echo signal and second echo signal are determined from the first echo signal, the last echo signal, the strongest echo signal and the second strongest echo signal. The first echo signal and the second echo signal are used for distance measurement of the target object. The method further includes, after determining the corresponding first echo signal and second echo signal: For one of the first and second echo signals, the echo signal is processed to obtain a third pulse width value. The third pulse width value is compared with a preset threshold. If the third pulse width value is less than the preset threshold, the laser beam flight time is determined based on a first time corresponding to the centroid position of the echo signal peak. If the third pulse width value is greater than the preset threshold, the laser beam flight time is determined based on a second time corresponding to a predetermined leading edge position of the echo signal. If the third pulse width value is equal to the preset threshold, the laser beam flight time is determined based on either the first or the second time. The distance between the lidar and the target object is determined based on the flight time.

2. The method according to claim 1, characterized in that, The determination of the corresponding first echo signal and second echo signal includes: When the preset dual-echo mode is the first mode, the strongest echo signal is determined to be the first echo signal, and the last echo signal is determined to be the second echo signal; the first mode corresponds to a scenario where there are highly reflective objects in the external environment of the lidar. When the preset dual-echo mode is the second mode, the strongest echo signal is determined to be the first echo signal, and the second strongest echo signal is determined to be the second echo signal; the second mode corresponds to a scenario where there are retroreflective objects in the external environment of the lidar.

3. The method according to claim 1, characterized in that, After determining the corresponding first echo signal and second echo signal, the method further includes: The first echo signal is processed to obtain a first ranging value and / or a first pulse width value; The second echo signal is processed to obtain a second ranging value and / or a second pulse width value; The ranging result of the target object is compensated using at least one of the first ranging value, the first pulse width value, the second ranging value, and the second pulse width value.

4. The method according to claim 1, characterized in that, The preset threshold includes any one of the following: The first value representing the pulse width of the echo signal at the critical state between saturation and unsaturation; A second value representing the pulse width at which distortion begins to occur on the falling edge of the echo signal, the second value being greater than the first value; and A third value that is greater than the first value and less than the second value.

5. A ranging method for a lidar, characterized in that, include: Emit a laser beam; Receive the echo beam reflected by the laser beam from the target object; Determine whether the echo mode corresponding to the current working mode is single echo mode or dual echo mode; In the dual-echo mode, multiple echo signals corresponding to the echo beam are acquired, and the distance measurement result of the target object is acquired according to the processing method of multiple echo signals according to any one of claims 1-4. In the single-echo mode, a third echo signal corresponding to the echo beam is acquired, and the distance measurement result of the target object is obtained based on the third echo signal.

6. A processing device for multi-echo signals, characterized in that, include: The receiving module is used to acquire multiple echo signals within a preset time period; The processing module is configured to: determine the first echo signal and the last echo signal among the plurality of echo signals based on the sampling time of each echo signal; determine at least two echo signals with the largest amplitude among the plurality of echo signals based on the amplitude of each echo signal; determine the strongest echo signal and the second strongest echo signal from the at least two echo signals based on a fixed threshold pulse width of the at least two echo signals; and determine the corresponding first echo signal and second echo signal from the first echo signal, the last echo signal, the strongest echo signal, and the second strongest echo signal according to a preset dual echo mode, wherein the first echo signal and the second echo signal are used for distance measurement of the target object. The device further includes: a calculation module, configured to process one of the echo signals, the first and the second, to obtain a third pulse width value; compare the third pulse width value with a preset threshold; if the third pulse width value is less than the preset threshold, determine the laser beam flight time based on a first time corresponding to the centroid position of the peak of the echo signal; if the third pulse width value is greater than the preset threshold, determine the laser beam flight time based on a second time corresponding to a predetermined leading edge position of the echo signal; and if the third pulse width value is equal to the preset threshold, determine the laser beam flight time based on either the first or the second time; and determine the distance between the lidar and the target object based on the flight time.

7. The apparatus according to claim 6, characterized in that, The processing module is further configured to, when the preset dual-echo mode is the first mode, determine that the strongest echo signal is the first echo signal and the last echo signal is the second echo signal; the first mode corresponds to a scenario where there are highly reflective objects in the external environment of the lidar; when the preset dual-echo mode is the second mode, determine that the strongest echo signal is the first echo signal and the second strongest echo signal is the second echo signal; the second mode corresponds to a scenario where there are retroreflective objects in the external environment of the lidar.

8. The apparatus according to claim 6, characterized in that, The device further includes: The calculation module is used to process the first echo signal to obtain a first ranging value and / or a first pulse width value; to process the second echo signal to obtain a second ranging value and / or a second pulse width value; and to compensate the ranging result of the target object using at least one of the first ranging value, the first pulse width value, the second ranging value, and the second pulse width value.

9. The apparatus according to claim 6, characterized in that, The preset threshold includes any one of the following: a first value representing the pulse width of the echo signal at the critical state between saturation and unsaturation; a second value representing the pulse width when distortion begins to occur at the falling edge of the echo signal, the second value being greater than the first value; and a third value being greater than the first value and less than the second value.

10. A ranging device for a lidar system, characterized in that, include: The transmitting module is used to emit a laser beam; An echo receiving module is used to receive the echo beam reflected by the laser beam from the target object. The determination module is used to determine whether the echo mode corresponding to the current working mode is single echo mode or dual echo mode; A ranging processing module is configured to acquire multiple echo signals corresponding to the echo beam in the dual-echo mode, and acquire the ranging result of the target object according to the multi-echo signal processing method according to any one of claims 1-4; and to acquire a third echo signal corresponding to the echo beam in the single-echo mode, and acquire the ranging result of the target object according to the third echo signal.

11. A lidar, characterized in that, include: Memory used to store processor-executable instructions; A processor; wherein the processor is configured to, when executing the executable instructions, implement the method as described in any one of claims 1 to 5.

12. A computer-readable storage medium, characterized in that, The readable storage medium stores an executable program, wherein the executable program, when executed by a processor, implements the method as described in any one of claims 1 to 5.

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