Echo processing method and apparatus

Abstract

An echo processing method and apparatus, relating to the field of LiDAR, and used for filtering interference noise generated by a target object having high reflectivity. The method comprises: determining from a plurality of pieces of statistical data first statistical data of which the frequencies are greater than a preset threshold value, each of the plurality of pieces of statistical data comprising a plurality of times of flight and a frequency corresponding to each of the plurality of times of flight, and the statistical data being data obtained by accumulating and counting the times of flight recorded in corresponding pixels (S802); according to first position information and a preset offset value, determining interference noise, the first position information being position information of first pixels corresponding to the first statistical data in an SPAD array, the interference noise being generated by a target object having high reflectivity, and the preset offset value being a preset position offset value of the first pixels in the transverse direction of the SPAD array (S803); and filtering interference noise in the plurality of pieces of statistical data, so as to obtain target data (S805).

Description

Echo processing method and device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on August 8, 2023, with application number 202310997008.9 and application name “A Method and Device for Echo Processing”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the field of laser radar, and in particular to an echo processing method and device. Background Art

[0003] At present, the direct time of flight (DTOF) system in the laser radar calculates the distance information of the object through the detection signal emitted to the object and the echo signal reflected by the object. For example, the TOF system synchronizes with the time of emission of the detection signal and records the time of receiving the echo signal to determine the signal's flight time ΔT, and calculates the distance information of the object based on the flight time ΔT. However, in actual applications, the signal received by the TOF system may include various interference noise signals in addition to the echo signal reflected by the object, such as interference noise signals generated by highly reflective objects, interference noise signals generated by the laser radar itself, or interference noise signals caused by external ambient light. The interference noise signal will affect the flight time ΔT, resulting in errors in the calculated distance information. Therefore, how to filter out the interference noise signal has become a problem that needs to be solved urgently by those skilled in the art.

[0004] The prior art provides an echo processing technology, which first performs histogram statistics on the flight time to obtain a histogram of the flight time distribution, then performs high-order matched filtering on the histogram data to filter out low-frequency noise and high-frequency noise (for example, glitches) in the histogram data, and performs peak detection (also known as echo analysis) on the waveform corresponding to the filtered histogram data to obtain multiple peaks and multiple troughs. Waveforms with values ​​greater than a preset trough value and greater than a preset peak value are screened out to obtain echo data.

[0005] However, high-order matched filtering and peak detection cannot filter out the interfering noise signals generated by high-reflectivity objects.

[0006] Summary of the Invention

[0007] The present application provides an echo processing method and device, which relate to the field of laser radar and are used to filter out interference noise generated by target objects with high reflectivity.

[0008] To achieve the above objectives, this application adopts the following technical solutions:

[0009] In a first aspect, an echo processing method is provided, which is applied to a laser radar including a single-photon avalanche diode (SPAD) array, the SPAD array including multiple pixels arranged horizontally and vertically, each pixel including multiple single-photon avalanche diodes (SPAD), the method including: determining multiple statistical data based on the echo signal received by the laser radar, each of the multiple statistical data corresponding to a pixel; determining a first statistical data having a frequency greater than a preset threshold value among the multiple statistical data, each of the multiple statistical data including multiple flight times, and a frequency corresponding to each of the multiple flight times, the statistical data being data obtained by accumulating and statistically analyzing the flight times recorded in the corresponding pixel; determining interference noise based on first position information and a preset offset value, the first position information being the position information of the first pixel corresponding to the first statistical data in the SPAD array, the interference noise being generated by a target object with high reflectivity, and the preset offset value being a preset position offset value of the first pixel along the horizontal direction of the SPAD array; filtering out the interference noise in the multiple statistical data to obtain target data.

[0010] In the technical solution provided in the present application, interference noise of high-reflectivity objects determined by the first position information of the first pixel and the preset offset value in multiple statistical data is filtered out, thereby improving the accuracy of the target data; further, when the target data is used to calculate the distance to the object, the accuracy of the ranging is improved.

[0011] In a possible implementation of the first aspect, at least one pixel group located in the same row is determined based on first position information, where the pixel group includes one or multiple consecutive first pixels. Second position information of an interfering pixel is determined based on the first position information of the first first pixel, the first position information of the last first pixel in the at least one pixel group, and a preset offset value. Based on the second position information, statistical data in the interfering pixel is determined as interference noise. In this possible implementation, the second position information of the interfering pixel is determined, the statistical data in the interfering pixel is determined as interference noise, and the interference noise is filtered out, thereby improving the accuracy of the target data.

[0012] In a possible implementation of the first aspect, determining a first statistical data item having a frequency greater than a preset threshold among the multiple statistical data items includes: dividing the SPAD array into multiple regions, each region including at least one pixel; and simultaneously scanning the multiple regions to determine the first statistical data item. In this possible implementation, simultaneously scanning the multiple regions increases the rate at which the first statistical data item is determined.

[0013] In a possible implementation of the first aspect, after receiving the plurality of statistical data, the method further includes: performing low-order matched filtering on the plurality of statistical data. In the above possible implementation, noise, such as glitches, in the plurality of statistical data is filtered out, thereby improving the accuracy of the plurality of statistical data.

[0014] In a possible implementation of the first aspect, after obtaining the target data, the method further includes: performing high-order matched filtering on the target data. In the above possible implementation, the signal-to-noise ratio of the target data is improved.

[0015] In a possible implementation of the first aspect, the echo processing method is applied to a high reflectivity scene. In the above possible implementation, interference noise in a high reflectivity scene can be filtered out, thereby increasing the application scenarios of the echo processing method.

[0016] In a second aspect, an echo processing device is provided, which is applied to a laser radar including a single-photon avalanche diode (SPAD) array, the SPAD array including multiple pixels arranged horizontally and vertically, each pixel including multiple single-photon avalanche diodes (SPAD), and the echo processing device including: a determination unit for determining multiple statistical data based on the echo signal received by the laser radar, each of the multiple statistical data corresponding to a pixel; the determination unit is also used to determine a first statistical data in the multiple statistical data whose frequency is greater than a preset threshold, each of the multiple statistical data including multiple flight times and the frequency corresponding to each of the multiple flight times, the statistical data is data obtained by accumulating and counting the flight times recorded in the corresponding pixel; the determination unit is also used to determine interference noise based on first position information and a preset offset value, the first position information is the position information of the first pixel corresponding to the first statistical data in the SPAD array, the interference noise is generated by a target object with high reflectivity, and the preset offset value is a preset position offset value of the first pixel along the horizontal direction of the SPAD array; a filtering unit is used to filter out the interference noise in the multiple statistical data to obtain target data.

[0017] In a possible implementation of the second aspect, the determination unit is further used to: determine at least one pixel group located in the same row based on the first position information, the pixel group including one or multiple consecutive first pixels; determine the second position information of the interfering pixel based on the first position information of the first first pixel in the at least one pixel group, the first position information of the last first pixel and a preset offset value; and determine the statistical data in the interfering pixel as the interference noise based on the second position information.

[0018] In a possible implementation manner of the second aspect, the determination unit is further configured to: divide the SPAD array into multiple regions, each region including at least one pixel; and simultaneously scan the multiple regions to determine the first statistical data.

[0019] In a possible implementation manner of the second aspect, the apparatus further includes: a first filtering unit, configured to perform low-order matched filtering on the multiple statistical data.

[0020] In a possible implementation manner of the second aspect, the apparatus further includes: a second filtering unit, configured to perform high-order matched filtering on the target data.

[0021] In a possible implementation manner of the second aspect, the echo processing device is applied in a high reflectivity scenario.

[0022] In a third aspect, an echo processing device is provided, comprising: a processor, a memory and a communication interface, wherein the communication interface is used to transmit data, the memory is used to store instructions, and the processor is used to execute the echo processing method provided by the first aspect or any possible implementation of the first aspect.

[0023] In a fourth aspect, a laser radar is provided, which includes: a receiver, a transmitter, and an echo processing device provided by the above-mentioned second aspect or any possible implementation of the second aspect.

[0024] In a fifth aspect, a terminal device is provided, including: a laser radar, which is used to execute the echo processing method provided by the above-mentioned first aspect or any possible implementation method of the first aspect.

[0025] In a sixth aspect, a vehicle is provided, comprising a laser radar, wherein the laser radar is used to execute the echo processing method provided by the first aspect or any possible implementation of the first aspect.

[0026] In another aspect of the present application, a computer-readable storage medium is provided, which includes computer instructions. When the computer instructions are executed on an echo processing device, the echo processing device executes the echo processing method provided by the first aspect or any possible implementation of the first aspect.

[0027] In another aspect of the present application, a computer program product containing instructions is provided. When the computer program product is run on a computer device, the computer device executes the echo processing method provided by the first aspect or any possible implementation of the first aspect.

[0028] It can be understood that the echo processing device, laser radar, terminal equipment, vehicle, computer-readable storage medium and computer program product provided above can be used to execute the corresponding method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method provided above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a schematic structural diagram of a DTOF system;

[0030] FIG2 is a flow chart of a filtering method;

[0031] FIG3 is a schematic flow chart of another filtering method;

[0032] FIG4 is a schematic structural diagram of a terminal device provided in an embodiment of the present application;

[0033] FIG5 is a schematic diagram of the structure of another terminal device provided in an embodiment of the present application;

[0034] FIG6 is a schematic structural diagram of another terminal device provided in an embodiment of the present application;

[0035] FIG7 is a schematic structural diagram of a SPAD array provided in an embodiment of the present application;

[0036] FIG8 is a schematic flow chart of an echo processing method provided in an embodiment of the present application;

[0037] FIG9 is a schematic diagram of a histogram provided in an embodiment of the present application;

[0038] FIG10 is a schematic structural diagram of another SPAD array provided in an embodiment of the present application;

[0039] FIG11 is a schematic flow chart of another echo processing method provided in an embodiment of the present application;

[0040] FIG12 is a schematic structural diagram of another SPAD array provided in an embodiment of the present application;

[0041] FIG13 is a schematic diagram of an application scenario provided by an embodiment of the present application;

[0042] FIG14 is a schematic structural diagram of an echo processing device provided in an embodiment of the present application;

[0043] FIG15 is a schematic structural diagram of another echo processing device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] In this application, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple. In addition, the embodiments of this application use words such as "first" and "second" to distinguish between identical or similar items with substantially the same function and effect. For example, the first threshold and the second threshold are merely to distinguish different thresholds and do not define their order of precedence. Those skilled in the art will understand that words such as "first" and "second" do not define the quantity or execution order.

[0045] It should be noted that, in this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" or "for example" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0046] Before introducing the embodiments of the present application, the principle of direct time of flight (DTOF) ranging is briefly described first.

[0047] Direct time of flight (DTOF) systems in lidar calculate the distance to an object by emitting a detection signal and reflecting the return signal. For example, a TOF system synchronizes the time the detection signal is emitted and records the time the return signal is received to determine the signal's time of flight, ΔT. This time of flight is then used to calculate the distance to the object.

[0048] Currently, the DTOF system uses a single photon avalanche diode (SPAD) array in conjunction with a vertical cavity surface emitting laser (VCSEL) to achieve ranging.

[0049] Exemplarily, as shown in FIG1 , a DTOF system 100 includes a laser driver 101, a VCSEL 102, a receiver 103, a transmitting optical lens 104, and a receiving optical lens 105. The receiver 103 includes a SPAD array. The SPAD array may include multiple pixels (also referred to as channels), and the multiple pixels are also distributed in an array. Each pixel includes multiple SPADs in an array. Each pixel can be used to capture a single photon in a very short time and record its time and spatial position. For example, each pixel can include a time-to-digital converter (TDC). Each pixel records the time when a single photon is captured through the TDC and generates a histogram of the time-of-flight distribution.

[0050] Specifically, VCSEL 102, driven by laser driver 101, transmits a pulse signal (also called a detection signal) of a specific wavelength toward the target object through transmitting optical lens 104. The pulse signal is reflected by the target object within the field of view (FOV) of VCSEL 102. The receiving optical lens 105 focuses the reflected echo signal. Receiver 103 receives the echo signal through the SPAD array as a detection event and records the corresponding time. Following the above process, N detections are performed, resulting in N corresponding flight times. The flight times corresponding to each detection event are accumulated and statistically analyzed to generate a histogram of the flight time distribution. Interference noise signals are ignored in Figure 1.

[0051] The processing module calculates the target distance based on the flight time with the highest frequency. The target distance D satisfies the formula (1): D=(ΔT×C) / 2 (1)

[0052] Where ΔT is the time it takes to receive the echo signal, and C is the speed of light.

[0053] It should be noted that, in actual applications, the TOF system can determine the flight time by synchronizing with the time of transmitting the detection signal and recording the time of receiving the echo signal; it can also determine the flight time based on the difference between the time of transmitting the detection signal and the time of receiving the echo signal.

[0054] However, in practical applications, the signals received by a TOF system may include not only echo signals reflected by objects but also various interference noise signals, such as those generated by highly reflective objects or ambient light. This interference noise can affect the time of flight ΔT, leading to errors in the calculated distance information. Therefore, filtering out this interference noise has become a pressing issue for those skilled in the art. Currently, two solutions are used to filter out this interference noise signal.

[0055] Solution 1: Filter the received signal by adjusting the echo detection threshold of the receiving channel. The specific method flow chart is shown in Figure 2. S201: Obtain point cloud data generated by the lidar and the image corresponding to the point cloud data. S202: Based on the pixel data of each pixel in the image, determine the image region that meets preset conditions. S203: Obtain the point data set corresponding to the image region. S204: Based on the pixel data of the image region, adjust the echo detection threshold of the receiving channel corresponding to the point data set. This allows the echo signal to be detected from the complex received signal.

[0056] Solution 2: Filter the received signal through high-order matched filtering and peak detection. Specifically, first perform histogram statistics on the flight time to obtain a histogram of the flight time distribution. Then, perform high-order matched filtering on the histogram data to filter out low-frequency noise and high-frequency noise (such as glitches) in the histogram data. Peak detection (also known as echo analysis) is performed on the waveform corresponding to the filtered histogram data to obtain multiple peaks and multiple troughs. Waveforms with values ​​greater than the preset trough value and greater than the preset peak value are selected to obtain the echo data.

[0057] Exemplarily, as shown in Figure 3, assuming that the SPAD array is a 6×6 array, the SPADs in the 1st column L0 to the 3rd column L2 belong to the 1st pixel, and the SPADs in the 3rd column L3 to the 6th column L5 belong to the 2nd pixel, the recorded flight times in the 1st pixel and the 2nd pixel are respectively subjected to histogram statistics to obtain the 1st histogram data and the 2nd histogram data, the 1st histogram data and the 2nd histogram data are respectively filtered, and the filtered 1st histogram data and the filtered 2nd histogram data are echo detected to obtain the 1st echo data and the 2nd echo data, and the 1st echo data and the 2nd echo data are merged to obtain the echo data.

[0058] However, neither the first nor the second solution can filter out the interference noise signal generated by the target object with high reflectivity.

[0059] Based on this, the present application provides an echo processing method and device, which is applied to a laser radar including a SPAD array, the SPAD array including multiple pixels, each pixel including multiple single-photon avalanche diodes SPAD, and the method including: determining multiple statistical data based on the echo signal received by the laser radar, each of the multiple statistical data corresponding to a pixel; determining a first statistical data in the multiple statistical data whose frequency is greater than a preset threshold, each of the multiple statistical data including multiple flight times, and the frequency corresponding to each of the multiple flight times, the statistical data is the data obtained by accumulating and counting the flight times recorded in the corresponding pixels; determining interference noise based on first position information and a preset offset value, the first position information is the position information of the first pixel corresponding to the first statistical data in the SPAD array, the interference noise is generated by a target object with high reflectivity, and the preset offset value is a preset position offset value of the first pixel along the horizontal direction of the SPAD array; filtering out the interference noise in the multiple statistical data to obtain target data.

[0060] In this solution, interference noise generated by a target object with high reflectivity determined by the first position information of the first pixel and a preset offset value in multiple statistical data is filtered out, thereby improving the accuracy of the target data; further, when the target data is used to calculate the distance to the object, the accuracy of the ranging is improved.

[0061] The echo processing method provided in this embodiment can be applied to a laser radar, which can be applied to a terminal device, including but not limited to mobile devices (such as mobile phones and tablets), wearable devices, cars, consumer terminal devices, mobile robots, robot vacuums, and drones. For example, as shown in FIG4 , a terminal device 400 includes a laser radar 401 and an echo processing device 402 .

[0062] The laser radar 401 can be used to generate statistical data. For example, as shown in FIG5 , the laser radar 401 includes a transmitter 4010 and a receiver 4011 .

[0063] In practical applications, the echo processing device 402 can be integrated with the laser radar 401 or provided separately. When the echo processing device 402 can be provided separately from the laser radar 401, the structure of the terminal device 400 is shown in Figure 4. When the echo processing device 402 can be integrated with the laser radar 401, the structure of the terminal device 400 is shown in Figure 6.

[0064] Transmitter 4010 can be used to transmit a detection signal toward a target object. For example, the detection signal can be a pulse signal of a specific wavelength. For example, transmitter 4010 can include a VCSEL, which can be used to transmit a pulse signal of a specific wavelength toward the target object. Optionally, transmitter 4010 can also include a laser driver and an optical lens. The laser driver is used to drive the VCSEL to transmit the detection signal. The optical lens can be used to focus light. For example, when the optical lens is provided at the transmitting end, it can be used to focus the detection signal emitted by the VCSEL.

[0065] The receiver 4011 can be used to capture the signal emitted by the target object and record the corresponding flight time. For example, the receiver may include a SPAD array. For example, as shown in FIG7 , the SPAD array may include multiple pixels arranged horizontally and vertically, and the multiple pixels are also distributed in an array, and each pixel includes multiple SPADs in an array. Each pixel can be used to capture a single photon in a very short time and record its time and spatial position. For example, each pixel may include a TDC, which can be used to record the time when a single photon is captured and generate a histogram of the flight time distribution to obtain a statistical data. Optionally, the receiver 4011 may also include an optical lens for focusing the signal reflected by the target object. The TDC is not shown in FIG7 , and an example is taken in which four SPADs are included in one pixel.

[0066] The echo processing device 402 may be used to perform noise processing on the statistical data to filter out interference noise generated by target objects with high reflectivity in the statistical data. For example, the echo processing device may include a determination unit and a filtering unit.

[0067] The determining unit may be configured to determine a first statistical data, for example, the determining unit may be configured to scan a plurality of pixels in the SPAD array to determine a first statistical data having a frequency greater than a preset threshold. The determining unit may also be configured to determine interference noise, for example, the determining unit may be configured to determine the interference noise based on position information of a first pixel corresponding to the first statistical data in the SPAD array and a preset offset value.

[0068] The filtering unit can be used to filter out interference noise in multiple statistical data to obtain target data.

[0069] The communication interface may be used to transmit data, for example, the communication interface may be used to output target data. The communication interface may include a mobile industry processor interface (MIPI).

[0070] It should be noted that when the transmitter 4010 and the receiver 4011 are integrated into one system, the system may be the DTOF system shown in FIG. 1 above.

[0071] In actual applications, when the LiDAR detects a target object with a normal scattering surface (a surface with relatively low reflectivity), only the echo beam formed at the center of gravity of the beam is received by the LiDAR to generate a valid point. However, when the LiDAR detects a target object with high reflectivity (such as road signs, road cones, signboards, etc.), due to the relatively high reflectivity of the target object, in addition to the echo beam generating a valid point for the center of gravity of the beam, the echo signal formed by the non-center of gravity of the beam falling in the high reflectivity area is also very strong, which can also be received by the LiDAR and generate an invalid point. In this case, the area where the point cloud originally composed of valid points is located will expand due to the appearance and addition of invalid points, that is, the point cloud will undergo point cloud expansion, which will cause the point cloud formed by the LiDAR detection to deviate from the actual object, affecting the detection performance of the LiDAR.

[0072] Based on this, the echo processing method provided in the embodiment of the present application is introduced and explained below in combination with the laser radar shown in Figure 6.

[0073] FIG8 is a flow chart of an echo processing method provided in an embodiment of the present application, the method comprising:

[0074] S801: Determine multiple statistical data based on the echo signal received by the laser radar, each of the multiple statistical data corresponds to a pixel.

[0075] Statistical data can also be called histogram data. In practical applications, each pixel in the SPAD array can be used to capture the signal reflected from the corresponding area of ​​the target object in a very short time, record the corresponding time, and generate a histogram of the flight time. Therefore, each pixel corresponds to a statistical data, and multiple pixels in the SPAD array can generate multiple statistical data.

[0076] In addition, each statistical data in the plurality of statistical data corresponds to a pixel, that is, each statistical data is data in the corresponding pixel.

[0077] S802: Determine a first statistical data having a frequency greater than a preset threshold value among multiple statistical data, each statistical data among the multiple statistical data includes multiple flight times and a frequency corresponding to each flight time among the multiple flight times, and the statistical data is data obtained by accumulating and counting the flight times recorded in the corresponding pixels.

[0078] In addition, the preset threshold is the maximum frequency in the signal reflected by the target object with normal reflectivity. The specific value of the preset threshold can be set according to actual needs and the experience of relevant staff, and the embodiments of the present application do not make specific limitations on this.

[0079] In addition, the SPAD array in the embodiment of the present application can be a two-dimensional planar array, which can also be called a surface array.

[0080] In addition, frequency is obtained by accumulating and counting the flight time. The frequency corresponding to a certain flight time is used to indicate the number of times a certain flight time occurs. Frequency can also be called the number of times.

[0081] Optionally, the first statistical data can be determined by one determination unit or by multiple determination units, and the frequency used to determine the first statistical data can be the maximum frequency in the statistical data or the frequency corresponding to each flight time in multiple flight times. The specific process of determining the first statistical data in different situations is introduced and explained below.

[0082] In the first case, a first statistical data is determined by a determination unit, and the frequency is a maximum frequency in the statistical data. Specifically, the determination unit first sequentially scans each pixel in the SPAD array, determines the maximum frequency of the statistical data in each pixel, compares the maximum frequency with a preset threshold, and determines a first statistical data whose maximum frequency is greater than the preset threshold.

[0083] In the second case, a first statistical data is determined by a determination unit, where the frequency is the frequency corresponding to each of the plurality of flight times. Specifically, the determination unit first sequentially scans each pixel in the SPAD array, determines the frequency corresponding to each flight time in each statistical data, compares the frequency corresponding to each flight time with a preset threshold, and determines a first statistical data having a frequency greater than the preset threshold.

[0084] If the first statistical data is determined by multiple determination units, then determining the first statistical data whose frequency is greater than a preset threshold among the multiple statistical data includes: dividing the SPAD array into multiple areas, each area includes at least one pixel, each area corresponds to a determination unit, and multiple areas correspond to multiple determination units; multiple determination units scan multiple areas at the same time to determine the first statistical data.

[0085] In a third case, the first statistical data is determined by multiple determination units, and the frequency is the maximum frequency in the statistical data. Multiple regions are scanned simultaneously by the multiple determination units corresponding to the multiple regions. Specifically, for each of the multiple regions, the determination unit corresponding to the region scans at least one pixel included in the region, determines the maximum frequency in the statistical data of the at least one pixel, compares the maximum frequency with a preset threshold, and determines the first statistical data whose maximum frequency is greater than the preset threshold.

[0086] In a fourth scenario, the first statistical data is determined by multiple determination units, and the frequency is the frequency corresponding to each of the multiple flight times. Specifically, multiple regions are scanned simultaneously by the multiple determination units corresponding to the multiple regions. Specifically, for each of the multiple regions, the determination unit corresponding to the region scans at least one pixel included in the region, determines the frequency corresponding to each flight time in the statistical data of the at least one pixel, and compares the frequency corresponding to each flight time with a preset threshold to determine the first statistical data having a frequency greater than the preset threshold.

[0087] In the first and second cases above, one processing unit is used for processing. When the processing unit is integrated into the echo processing device, the area of ​​the echo processing device is reduced and the integration level is improved.

[0088] In the third and fourth cases above, multiple processing units simultaneously scan and determine the first statistical data, which shortens the time for determining the first statistical data and improves efficiency.

[0089] It should be noted that if the target object is not a high-reflectivity object or there is no high-reflectivity area, the histogram generated by the statistical data of each pixel in the SPAD array is shown in Figure 9(a). Figure 9(a) is a schematic diagram of a histogram under ideal conditions, where the horizontal axis is flight time t and the vertical axis is frequency f. The frequency corresponding to flight time t1 is f1. Other interference noise is ignored in Figure 9(a).

[0090] For example, if the target object is a highly reflective object, the histogram generated by the statistical data in each pixel in the SPAD array is shown in (b) of FIG9 , where the horizontal axis is the flight time t and the vertical axis is the frequency f. Each flight time may correspond to a frequency, for example, the frequency corresponding to the flight time t0 is f0, the frequency corresponding to the flight time t1 is f11, and the frequency corresponding to the flight time t2 is f2. The frequency f0 corresponding to the flight time t0 and the frequency f2 corresponding to the flight time t2 are interference noise.

[0091] It should be noted that when the SPAD array is divided into regions, the number of pixels included in each region may be the same or different, and this embodiment of the present application does not specifically limit this.

[0092] For example, as shown in Figure 10, assuming that the SPAD array can be a 10×10 array, the SPAD array can include 25 pixels, each pixel can include 4 SPADs, and the 4 SPADs form a 2×2 array. The SPAD array is divided into 5 regions, and their identification information can be represented as R1 to R5 respectively. Each region includes 5 pixels, and each region corresponds to a determination unit for processing statistical data of the pixels in the region. Figure 10 takes the example of each region including 5 pixels and each pixel including 4 SPADs. Figure 10 only shows the identification information of some regions and some pixels.

[0093] S803: Determine the interference noise based on the first position information and the preset offset value, where the first position information is the position information of the first pixel corresponding to the first statistical data in the SPAD array, the interference noise is generated by a target object with high reflectivity, and the preset offset value is the preset position offset value of the first pixel along the horizontal direction of the SPAD array.

[0094] Among them, the transverse direction can also be called the horizontal direction, that is, the preset offset value is a preset position offset value along the horizontal direction of the SPAD array. For example, the preset offset value can be a horizontal left offset value and a horizontal right offset value. The preset offset value is pre-set. For example, the preset offset value can be pre-set based on the specific size of the pixel and the distance between pixels. The specific numerical value can be set according to actual needs and the experience of relevant staff. The embodiment of the present application does not make specific limitations on this.

[0095] In addition, the SPAD array includes a plurality of first pixels, and the preset offset value corresponding to each of the plurality of first pixels is equal.

[0096] In a possible implementation, the first position information is determined in real time. Exemplarily, as shown in FIG11 , before step S803 , the echo processing method provided by the present application further includes step S804 : determining the first position information.

[0097] Exemplarily, a coordinate system is established on the first plane where the SPAD array is located, the direction parallel to the first plane and horizontally to the right is determined as the X-axis, the direction parallel to the first plane and vertically upward is determined as the Y-axis, and the first position information of the first pixel P1 corresponding to the first statistical data S1 in the SPAD array is determined to be (XP1, Y2).

[0098] In another possible implementation, the first position information may be predetermined. For example, the position information of each pixel may be determined during the design of the SPAD array, and the determined position information of each pixel may be stored in a corresponding memory. When executing the relevant steps, the first position information may be directly obtained from the corresponding memory. The embodiments of the present application do not specifically limit the method for obtaining the first position information.

[0099] Due to the characteristics of the target object itself (high reflectivity), the point cloud formed by the lidar detection will expand. For example, the area where the point cloud composed of valid points is located (i.e., the high reflectivity area) will expand a certain distance horizontally to the left and horizontally to the right (i.e., the interference area). Corresponding to the SPAD array, the pixel corresponding to the high reflectivity area is the first pixel, and the pixels within a certain distance range horizontally to the left of the first pixel and the pixels within a certain distance range horizontally to the right are interference pixels. The interference pixels record the flight time of the interference area (i.e., interference noise). Therefore, determining the position of the interference pixel can determine the interference noise.

[0100] Furthermore, interference noise is determined based on the first position information and a preset offset value, including: determining at least one pixel group located in the same row based on the first position information, the pixel group including one or multiple consecutive first pixels; determining second position information of the interference pixel based on the first position information of the first first pixel in at least one pixel group, the first position information of the last first pixel and the preset offset value; and determining statistical data in the interference pixel as interference noise based on the second position information.

[0101] When the pixel group includes a first pixel, the first first pixel and the last first pixel in the pixel group are the same pixel, and the first first pixel and the last first pixel both indicate the first pixel included in the pixel group.

[0102] When a pixel group includes a plurality of consecutive first pixels, the first first pixel may be the first first pixel in the pixel group counted from left to right, or the first first pixel in the pixel group counted from right to left, which is not specifically limited in this application.

[0103] For example, as shown in Figure 12, assuming that the SPAD array can be a 20×10 array, the SPAD array can include 50 pixels, each pixel can include 4 SPADs, and the 4 SPADs form a 2×2 array. The first statistical data are S1 to S8, and the corresponding first pixels are P1 to P8. The second row includes two pixel groups, the first pixel group includes the first pixel P1, and the second pixel group includes the first pixel P5. The third row includes two pixel groups, the first pixel group includes the consecutive first pixel P2, the first pixel P3, and the first pixel P4, and the second pixel group includes the consecutive first pixel P6, the first pixel P7, and the first pixel P8.

[0104] A coordinate system is established on the first plane where the SPAD array is located, and the direction parallel to the first plane and horizontally to the right is determined as the X-axis, and the direction parallel to the first plane and vertically upward is determined as the Y-axis, so that the first position information of the first pixel can be determined. Among them, the first position information (XP1, Y2) of the first pixel P1, the first position information (XP2, Y3) of the first pixel P2, the first position information (XP3, Y3) of the first pixel P3, the first position information (XP4, Y3) of the first pixel P4, the first position information (XP5, Y2) of the first pixel P5, the first position information (XP6, Y3) of the first pixel P6, the first position information (XP7, Y3) of the first pixel P7, and the first position information (XP8, Y3) of the first pixel P8.

[0105] Based on the first position information (XP1, Y2) of the first pixel P1 in the first pixel group in the second row, the preset offset value M is offset in both the horizontal left and horizontal right directions to determine the second position information (XP1-M, Y2) of the interference pixel IP1, and the second position information (XP1+M, Y2) of the interference pixel IP2; based on the first position information (XP5, Y2) of the first pixel P5 in the second pixel group in the second row, the preset offset value M is offset in both the horizontal left and horizontal right directions to determine the second position information (XP5-M, Y2) of the interference pixel IP3, and the second position information (XP5+M, Y2) of the interference pixel IP4. Based on the first position information (XP2, Y3) of the first pixel P2 in the first pixel group in the third row being horizontally shifted to the left by a preset offset value M, the second position information (XP2-M, Y3) of the interfering pixel IP5 is determined. Based on the first position information (XP4, Y3) of the first pixel P4 being horizontally shifted to the right by a preset offset value M, the second position information (XP4+M, Y3) of the interfering pixel IP6 is determined. Based on the first position information (XP6, Y3) of the first pixel P6 in the second pixel group in the third row being horizontally shifted to the left by a preset offset value M, the second position information (XP6-M, Y3) of the interfering pixel IP7 is determined. Based on the first position information (XP8, Y3) of the first pixel P8 being horizontally shifted to the right by a preset offset value M, the second position information (XP8+M, Y3) of the interfering pixel IP8 is determined. Based on the determined second position information, the statistical data of the interfering pixels IP1 to IP8 is determined as interference noise.

[0106] S805: Filter out interference noise in the multiple statistical data to obtain target data.

[0107] Optionally, as shown in FIG11 , after step S801, the echo processing method provided by the present application further includes S806: performing low-order matched filtering on multiple statistical data. Matched filtering can suppress high-frequency signals and low-frequency signals, allowing intermediate-frequency signals to pass through, thereby achieving frequency interception of the signal and suppressing the high-frequency and low-frequency components in the signal, thereby achieving the purpose of filtering. Low-order matched filtering is to perform matched filtering on statistical data using a relatively low order to filter out low-frequency noise and high-frequency noise in the statistical data. In this embodiment, performing low-order matched filtering on multiple statistical data can filter out low-frequency noise and high-frequency noise (e.g., glitches) in the multiple statistical data, thereby improving the accuracy of the multiple statistical data.

[0108] Optionally, as shown in FIG11 , after step S805, the echo processing method provided by the present application further includes, at step S807, performing high-order matched filtering on the target data. High-order matched filtering employs a higher-order matched filtering technique to remove low-frequency and high-frequency noise from the target data. In this embodiment, performing high-order matched filtering on the target data can improve the signal-to-noise ratio of the target data.

[0109] Furthermore, the echo processing method provided in the embodiments of the present application is applied to high-reflectivity scenarios, for example, scenarios including target objects with high reflectivity, such as road signs, road cones, and signboards.

[0110] Optionally, the echo processing method provided in the embodiment of the present application can be applied to a scenario where the distance from a vehicle to a target object is measured. For example, as shown in FIG13 , FIG13 is an application scenario of the echo processing method provided in the embodiment of the present application, wherein the scenario includes: a vehicle, a laser radar provided in the vehicle, the laser radar including an echo processing device, the laser radar being used to transmit a detection signal to the target object, the laser radar being used to receive an echo signal reflected from the target object, and the echo processing device being used to execute the relevant steps in the above method embodiment to obtain the true distance between the vehicle and the target object.

[0111] The echo processing method provided in the present application filters out interference noise generated by target objects with high reflectivity in multiple statistical data, thereby improving the accuracy of target data; further, when using target data to calculate the distance to the object, the accuracy of ranging is improved.

[0112] It is understood that, in order to implement the above-mentioned functions, the echo processing device includes hardware structures and / or software modules corresponding to the respective functions. Those skilled in the art will readily appreciate that, in conjunction with the various exemplary echo processing method steps described in the embodiments herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is implemented in hardware or in a manner driven by computer software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0113] In the embodiments of the present application, the echo processing device can be divided into functional modules based on the above-described method examples. For example, individual functional modules can be divided according to their respective functions, or two or more functions can be integrated into a single processing module. The integrated modules can be implemented in the form of hardware or software functional modules. It should be noted that the module division in the embodiments of the present application is illustrative and represents only a logical functional division. In actual implementation, other division methods may be used.

[0114] FIG14 shows a possible schematic diagram of the structure of an echo processing device involved in the above embodiment, in which the functional modules are divided according to their respective functions. The echo processing device includes a determination unit 140 and a filtering unit 141. The determination unit 140 is used to support the echo processing device in executing S801, S802, and S803 in the above method embodiment; the filtering unit 141 is used to support the echo processing device in executing S805 in the above method embodiment.

[0115] Optionally, as shown in FIG15 , the echo processing device may further include: a first filtering unit 142 and a second filtering unit 143 , wherein the first filtering unit is used to support the echo processing device to execute S806 in the above method embodiment; and the second filtering unit is used to support the echo processing device to execute S807 in the above method embodiment.

[0116] It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and will not be repeated here. The device provided in the embodiment of the present application is used to perform the corresponding functions in the above embodiment, so it can achieve the same effect as the above control method.

[0117] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0118] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0119] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling the device to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program noise, such as a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0120] In another aspect of the present application, an echo processing device is provided, comprising: a processor, a memory, and a communication interface, wherein the communication interface is used to transmit data, the memory is used to store instructions, and the processor is used to execute relevant steps in the above method embodiment.

[0121] Another aspect of the present application provides a laser radar, comprising a receiver, a transmitter, and an echo processing device. The transmitter is configured to transmit laser signals, the receiver is configured to receive echo signals, and the echo processing device is configured to perform the relevant steps in the above-described method embodiments. The echo processing device may be the echo processing device provided in FIG. 4 , FIG. 5 , or FIG. 6 .

[0122] Another aspect of the present application provides a terminal device, including: a laser radar, the laser radar being used to perform the relevant steps in the above method embodiment. The terminal device may be the terminal device shown in Figure 4, Figure 5 or Figure 6 above.

[0123] In another aspect of the present application, a vehicle is provided, comprising a laser radar, which is used to execute the relevant steps in the above method embodiment.

[0124] In another aspect of the present application, a computer-readable storage medium is provided, which includes computer instructions. When the computer instructions are executed on an echo processing device, the echo processing device executes the relevant steps in the above method embodiments.

[0125] In another aspect of the present application, a computer program product comprising instructions is provided. When the computer program product is run on a computer device, the computer device is caused to execute the relevant steps in the above method embodiments.

[0126] Finally, it should be noted that the above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. An echo processing method, characterized in that: Applied to a laser radar including a single photon avalanche diode (SPAD) array, the SPAD array including a plurality of pixels arranged horizontally and vertically, each pixel including a plurality of single photon avalanche diodes (SPAD), the method comprising: Determine a plurality of statistical data according to the echo signal received by the laser radar, each statistical data of the plurality of statistical data corresponding to a pixel; Determine a first statistical data having a frequency greater than a preset threshold value among the multiple statistical data, each of the multiple statistical data includes multiple flight times and a frequency corresponding to each of the multiple flight times, and the statistical data is data obtained by accumulating and counting the flight times recorded in the corresponding pixels; Determine interference noise according to first position information and a preset offset value, wherein the first position information is position information of a first pixel corresponding to the first statistical data in the SPAD array, the interference noise is generated by a target object with high reflectivity, and the preset offset value is a preset position offset value of the first pixel along the lateral direction of the SPAD array; The interference noise in the multiple statistical data is filtered out to obtain target data.

2. The method according to claim 1, characterized in that: The determining the interference noise according to the first position information and the preset offset value includes: Determine, according to the first position information, at least one pixel group located in the same row, the pixel group including one or a plurality of consecutive first pixels; Determine second position information of the interfering pixel according to first position information of a first first pixel in the at least one pixel group, first position information of a last first pixel and the preset offset value; According to the second position information, statistical data in the interference pixels are determined as the interference noise.

3. The method according to claim 1 or 2, characterized in that: The step of determining a first statistical data having a frequency greater than a preset threshold value among the plurality of statistical data comprises: Dividing the SPAD array into a plurality of regions, each region including at least one pixel; The plurality of regions are scanned simultaneously to determine the first statistical data.

4. The method according to any one of claims 1 to 3, characterized in that: After receiving the plurality of statistical data, the method further comprises: A low-order matched filtering is performed on the plurality of statistical data.

5. The method according to any one of claims 1 to 4, characterized in that: After obtaining the target data, the method further includes: A high-order matched filter is performed on the target data.

6. The method according to any one of claims 1 to 5, characterized in that: The echo processing method is applied in high reflectivity scenes.

7. An echo processing device, characterized in that: Applicable to a laser radar including a single photon avalanche diode SPAD array, the SPAD array including a plurality of pixels arranged horizontally and vertically, each pixel including a plurality of SPADs, the echo processing device including: A determination unit, configured to determine a plurality of statistical data according to an echo signal received by the laser radar, wherein each of the plurality of statistical data corresponds to a pixel; The determining unit is further configured to determine a first statistical data having a frequency greater than a preset threshold value among the plurality of statistical data, each of the plurality of statistical data comprising a plurality of flight times and a frequency corresponding to each of the plurality of flight times, and the statistical data is data obtained by accumulating and counting the flight times recorded in the corresponding pixels; The determination unit is further used to determine interference noise according to first position information and a preset offset value, wherein the first position information is position information of a first pixel corresponding to the first statistical data in the SPAD array, the interference noise is generated by a target object with high reflectivity, and the preset offset value is a preset position offset value of the first pixel along the transverse direction of the SPAD array; The filtering unit is used to filter out the interference noise in the multiple statistical data to obtain target data.

8. The device according to claim 7, characterized in that The determining unit is further configured to: Determine, according to the first position information, at least one pixel group located in the same row, the pixel group including one or a plurality of consecutive first pixels; According to the first position information of the first first pixel in the at least one pixel group, the first position information of the last first pixel information and the preset offset value, determining second position information of the interfering pixel; According to the second position information, statistical data in the interference pixels are determined as the interference noise.

9. The device according to claim 7 or 8, characterized in that The determining unit is further configured to: Dividing the SPAD array into a plurality of regions, each region including at least one pixel; The plurality of regions are scanned simultaneously to determine the first statistical data.

10. The device according to any one of claims 7 to 9, characterized in that: The device also includes: The first filtering unit is used to perform low-order matched filtering on the multiple statistical data.

11. The device according to any one of claims 7 to 10, characterized in that: The device also includes: The second filtering unit is used to perform high-order matched filtering on the target data.

12. The device according to any one of claims 7 to 11, characterized in that: The echo processing device is applied in high reflectivity scenarios.

13. An echo processing device, characterized in that: include: A processor, a memory and a communication interface, wherein the communication interface is used to transmit data, the memory is used to store instructions, and the processor is used to execute the echo processing method according to any one of claims 1 to 6.

14. A laser radar, characterized in that: The laser radar includes a transmitter, a receiver and an echo processing device as described in any one of claims 7 to 12, wherein the transmitter is used to transmit laser signals and the receiver is used to receive echo signals.

15. A terminal device, characterized in that: The terminal device includes a laser radar, which is used to execute the echo processing method as described in any one of claims 1-6.

16. A computer-readable storage medium, characterized in that: The computer-readable storage medium comprises computer instructions, and when the computer instructions are executed on an echo processing device, the echo processing device is enabled to perform the echo processing method according to any one of claims 1 to 6.

17. A computer program product comprising instructions, characterized in that When the computer program product is run on a computer device, the computer device is enabled to execute the echo processing method according to any one of claims 1 to 6.

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