WO2025030814A1 - Echo processing method and apparatus - Google Patents

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

This application claims the priority of 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”, all contents of which are incorporated by reference in this application.

Technical Field

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

Background Art

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 records the time of receiving the echo signal by synchronizing with the time of emitting the detection signal to determine the flight time ΔT of the signal, and calculates the distance information of the object based on the flight time ΔT. However, in practical 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 high reflectivity objects, interference noise signals formed 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.

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, performs peak detection (also known as echo analysis) on the waveform corresponding to the filtered histogram data to obtain multiple peaks and multiple troughs, and screens out waveforms that are greater than a preset trough value and greater than a preset peak value to obtain echo data.

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

Summary of the invention

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 a target object with high reflectivity.

In order to achieve the above objectives, this application adopts the following technical solutions:

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 with 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 counting 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.

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 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.

In a possible implementation of the first aspect, at least one pixel group located in the same row is determined based on the first position information, and the pixel group includes one or multiple consecutive first pixels; the second position information of the interfering pixel is determined 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 the statistical data in the interfering pixel is determined as interference noise based on the second position information. In the above possible implementation, the second position information of the interfering pixel is determined, the statistical data in the interfering pixel is determined as interference noise, the interference noise is filtered out, and the accuracy of the target data is improved.

In a possible implementation of the first aspect, determining a first statistical data having a frequency greater than a preset threshold value among multiple statistical data includes: dividing the SPAD array into multiple regions, each region including at least one pixel; and scanning the multiple regions simultaneously to determine the first statistical data. In the above possible implementation, scanning the multiple regions simultaneously increases the rate of determining the first statistical data.

In a possible implementation manner of the first aspect, after receiving the plurality of statistical data, the method further includes: The data is subjected to low-order matched filtering. In the above possible implementation, noises in multiple statistical data, such as burrs, are filtered out, thereby improving the accuracy of the multiple statistical data.

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.

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.

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, used to determine multiple statistical data based on the echo signal received by the laser radar, each of the multiple statistical data corresponds to a pixel; the determination unit is also used to determine a first statistical data with a frequency greater than a preset threshold value among the multiple statistical data, each of the multiple statistical data includes multiple flight times, and the frequency corresponding to each of the multiple flight times, the statistical data is data obtained after 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.

In a possible implementation of the second aspect, the determination unit is also 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.

In a possible implementation manner of the second aspect, the determination unit is further used 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.

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

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

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

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.

In a fourth aspect, a laser radar is provided, comprising: a receiver, a transmitter, and an echo processing device provided by the second aspect or any possible implementation of the second aspect.

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

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.

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.

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 executes the echo processing method provided by the first aspect or any possible implementation of the first aspect.

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

FIG1 is a schematic structural diagram of a DTOF system;

FIG2 is a schematic flow chart of a filtering method;

FIG3 is a schematic flow chart of another filtering method;

FIG4 is a schematic diagram of the structure of a terminal device provided in an embodiment of the present application;

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

FIG6 is a schematic diagram of the structure of another terminal device provided in an embodiment of the present application;

FIG7 is a schematic diagram of the structure of a SPAD array provided in an embodiment of the present application;

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

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

FIG10 is a schematic diagram of the structure of another SPAD array provided in an embodiment of the present application;

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

FIG12 is a schematic diagram of the structure of another SPAD array provided in an embodiment of the present application;

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

FIG14 is a schematic diagram of the structure of an echo processing device provided in an embodiment of the present application;

FIG. 15 is a schematic diagram of the structure of another echo processing device provided in an embodiment of the present application.

DETAILED DESCRIPTION

In this application, "at least one" means one or more, and "more" means two or more. "And/or" describes the association relationship of the associated objects, indicating that there may be three relationships. For example, A and/or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character "/" generally indicates that the objects associated with each other 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 items or plural items. For example, at least one of a, b, or c can mean: a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, c can be single or multiple. In addition, the embodiments of the present application use words such as "first" and "second" to distinguish between identical or similar items with substantially the same functions and effects. For example, the first threshold and the second threshold are only used to distinguish different thresholds, and their order is not limited. Those skilled in the art can understand that the words "first", "second", etc. do not limit the quantity and execution order.

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 as "exemplary" or "for example" in this application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

Before introducing the embodiments of the present application, the principle of direct time of flight (DTOF) ranging is briefly explained.

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 transmitting the detection signal and records the time of receiving the echo signal to determine the flight time ΔT of the signal, and calculates the distance information of the object based on the flight time ΔT.

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.

Exemplarily, as shown in FIG1 , the DTOF system 100 includes a laser driver 101, a VCSEL 102, a receiver 103, a transmitting end optical lens 104, and a receiving end optical lens 105. The receiver 103 includes a SPAD array. The SPAD array may include a plurality of pixels (also referred to as channels), and the plurality of pixels are also distributed in an array, each pixel includes a plurality of SPADs in an array, and each pixel may 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 time-to-digital converter (TDC), and each pixel records the time of capturing a single photon through the TDC, and generates a histogram of the flight time distribution.

Specifically, the VCSEL 102, driven by the laser driver 101, transmits a pulse signal (also called a detection signal) of a specific wavelength to the target object through the transmitting end optical lens 104. The pulse signal is reflected after encountering the target object within the field of view (FOV) of the VCSEL 102. The receiving end optical lens 105 focuses the reflected echo signal. The receiver 103 receives the echo signal through the SPAD array as a detection event and records the corresponding time. According to the above process, N detections are performed, and the corresponding The flight time corresponding to each detection event is accumulated to N flight times, and a histogram of the flight time distribution is generated. The interference noise signal is ignored in Figure 1.

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

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

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.

However, in practical 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 high reflectivity objects or interference noise signals caused by external ambient light. Interference noise signals will affect the flight time ΔT, resulting in errors in the calculated distance information. Therefore, how to filter out interference noise signals has become a problem that needs to be solved urgently by technicians in this field. At present, the following two solutions are used to filter out interference noise signals.

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 the point cloud data generated by the laser radar, and the image corresponding to the point cloud data; S202, based on the pixel data of each pixel in the image, determine the image area in the image that meets the preset conditions; S203, obtain the point data set corresponding to the image area; S204, adjust the echo detection threshold of the receiving channel corresponding to the point data set based on the pixel data of the image area. In order to detect the echo signal from the complex received signal.

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, perform peak detection (also known as echo analysis) on the waveform corresponding to the filtered histogram data, obtain multiple peaks and multiple troughs, and filter out waveforms that are greater than the preset trough value and greater than the preset peak value to obtain echo data.

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 first histogram data and the second histogram data, the first histogram data and the second histogram data are respectively filtered, and the filtered first histogram data and the filtered second histogram data are echo detected to obtain the first echo data and the second echo data, and the first echo data and the second echo data are merged to obtain the echo data.

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

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, the method including: determining multiple statistical data based on the echo signal received by the laser radar, each of the multiple statistical data corresponds to a pixel; determining a first statistical data with a frequency greater than a preset threshold value among the multiple statistical data, 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 after 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.

In this solution, interference noise generated by a target object with high reflectivity determined by first position information of a 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 ranging is improved.

The echo processing method provided in this embodiment can be applied to a laser radar, and the laser radar can be applied to a terminal device, and the terminal device can include but is not limited to a mobile device (such as a mobile phone, a tablet computer, etc.), a wearable device, a car, a consumer terminal device, a mobile robot, a sweeping robot, and a drone, etc. Exemplarily, as shown in FIG4 , a terminal device 400 includes a laser radar 401 and an echo processing device 402 .

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

In practical applications, the echo processing device 402 can be integrated with the laser radar 401, or can be separately provided. When the echo processing device 402 can be separately provided with the laser radar 401, the structural schematic diagram of the terminal device 400 is shown in FIG4. When the echo processing device 402 can be integrated with the laser radar 401, the structural schematic diagram of the terminal device 400 is shown in FIG6.

The transmitter 4010 can be used to transmit a detection signal to a target object. For example, the detection signal can be a pulse signal of a specific wavelength. For example, the transmitter 4010 can include a VCSEL, and the VCSEL can be used to transmit a pulse signal of a specific wavelength to a target object. Optionally, the 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 set at the transmitting end, it can be used to focus the detection signal emitted by the VCSEL.

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 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, receiver 4011 may also include an optical lens for focusing the signal reflected by the target object. TDC is not shown in FIG7, and 4 SPADs are included in one pixel as an example.

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.

The determination unit can be used to determine the first statistical data, for example, the determination unit can be used to scan multiple pixels in the SPAD array to determine the first statistical data with a frequency greater than a preset threshold. The determination unit is also used to determine interference noise, for example, the determination unit is also used to determine the interference noise based on the position information of the first pixel corresponding to the first statistical data in the SPAD array and the preset offset value.

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

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).

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.

In actual applications, when the laser radar 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 laser radar to generate a valid point. However, when the laser radar detects a target object with high reflectivity (such as road signs, road cones, signboards, etc.), due to the high reflectivity of the target object, in addition to the echo beam at the center of gravity of the beam generating a valid point, the echo signal formed by the non-center of gravity of the beam falling in the high reflectivity area is also very strong, so it can also be received by the laser radar and generate invalid points. 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 expand, which will cause the point cloud formed by the laser radar detection to deviate from the actual object, affecting the detection performance of the laser radar.

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.

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

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.

The 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 by the corresponding area in the target object in a very short time, and record the corresponding time to generate a histogram about the flight time. Therefore, each pixel corresponds to a statistical data, and multiple pixels in the SPAD array correspond to multiple statistical data.

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.

S802: Determine a first statistical data having a frequency greater than a preset threshold value among 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.

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.

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.

In addition, the 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. The frequency can also be called the number of times.

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.

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

In the second case, the first statistical data is determined by a determination unit, and the frequency is the frequency corresponding to each flight time in the multiple flight times. Specifically, the determination unit first scans each pixel in the SPAD array in sequence, 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 the first statistical data whose frequency is greater than the preset threshold.

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 simultaneously to determine the first statistical data.

In the 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 multiple determination units corresponding to the multiple regions. Specifically, for each region in the multiple regions, at least one pixel included in the region is scanned by the determination unit corresponding to the region, the maximum frequency in the statistical data of the at least one pixel is determined, the maximum frequency is compared with a preset threshold, and the first statistical data whose maximum frequency is greater than the preset threshold is determined.

In the fourth case, the first statistical data is determined by multiple determination units, and the frequency is the frequency corresponding to each flight time in the multiple flight times. Specifically, multiple determination units corresponding to the multiple regions are used to scan multiple regions simultaneously. Specifically, for each region in 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, compares the frequency corresponding to each flight time with a preset threshold, and determines the first statistical data whose frequency is greater than the preset threshold.

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.

In the third and fourth situations 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.

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 in each pixel in the SPAD array is shown in Figure 9 (a), which is a schematic diagram of a histogram under an ideal state, where the horizontal axis is the flight time t, the vertical axis is the frequency f, and the frequency corresponding to the flight time t1 is f1. Other interference noises are ignored in Figure 9 (a).

Exemplarily, if the target object is an object with high reflectivity, the histogram generated by the statistical data in each pixel in the SPAD array is shown in (b) of FIG9 , wherein the horizontal axis is the flight time t, and the vertical axis is the frequency f, wherein 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. Among them, the frequency corresponding to the flight time t0 is f0, and the frequency corresponding to the flight time t2 is f2, which is interference noise.

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.

Exemplarily, as shown in FIG10 , 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 its 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 in the pixels in the region. FIG10 takes 5 pixels in each region and 4 SPADs in each pixel as an example. FIG10 only shows the identification information of some regions and some pixels.

S803: Determine interference noise according to first position information and a preset offset value, where 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.

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.

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.

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.

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).

In another possible implementation, the first position information may be predetermined. For example, the position information of each pixel may be determined in the process of designing the SPAD array, and the determined position information of each pixel may be stored in a corresponding memory, and the first position information may be directly obtained in the corresponding memory when executing the relevant steps. The embodiment of the present application does not specifically limit the method for obtaining the first position information.

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 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.

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.

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.

When the pixel group includes a plurality of continuous first pixels, the first first pixel may be the first first pixel counted from left to right in the pixel group, or the first first pixel counted from right to left, which is not specifically limited in the present application.

Exemplarily, as shown in FIG12 , 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, respectively. 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 a continuous first pixel P2, a first pixel P3, and a first pixel P4, and the second pixel group includes a continuous first pixel P6, a first pixel P7, and a first pixel P8.

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, and then 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.

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 interfering pixel IP1, and the second position information (XP1+M, Y2) of the interfering 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 interfering pixel IP3, and the second position information (XP5+M, Y2) of the interfering pixel IP4. The first position information (XP2, Y3) of the first pixel P2 in the first pixel group in the third row is horizontally shifted to the left by a preset offset value M, and the second position information (XP2-M, Y3) of the interfering pixel IP5 is determined. Based on the first position information of the first pixel P4 (XP4, Y3), 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, the second position information (XP6-M, Y3) of the interfering pixel IP7 is determined. Based on the first position information of the first pixel P8 (XP8, Y3), the second position information (XP8+M, Y3) of the interfering pixel IP8 is determined by horizontally shifting to the right by a preset offset value M. According to the determined second position information, the statistical data in the interfering pixels IP1 to IP8 are determined as interference noise.

S805: Filter out interference noise in multiple statistical data to obtain target data.

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. Among them, matched filtering can suppress high-frequency signals and low-frequency signals, allowing intermediate frequency signals to pass through, thereby realizing frequency interception of the signal, suppressing the high-frequency and low-frequency components in the signal, thereby achieving the purpose of filtering. Low-order matched filtering is to use a relatively low order to perform matched filtering on statistical data to filter out low-frequency noise and high-frequency noise in the statistical data. In this embodiment, low-order matched filtering is performed on multiple statistical data, which can filter out low-frequency noise and high-frequency noise (for example, burrs) in multiple statistical data, thereby improving the accuracy of multiple statistical data.

Optionally, as shown in FIG11, after step S805, the echo processing method provided by the present application further includes S807: performing high-order matched filtering on the target data. The high-order matched filtering is to use a higher order to perform matched filtering on the target data to filter out low-frequency noise and high-frequency noise in 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.

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

Optionally, the echo processing method provided in the embodiment of the present application can be applied to the scenario of measuring the distance from the vehicle to the target object. Exemplarily, as shown in FIG13, FIG13 is an application scenario of the echo processing method provided in the embodiment of the present application, and the scenario includes: a vehicle, a laser radar is provided in the vehicle, the laser radar includes an echo processing device, the laser radar can be used to transmit a detection signal to the target object, the laser radar can be used to receive an echo signal reflected from the target object, and the echo processing device can be used to execute the relevant steps in the above method embodiment to obtain the real distance between the vehicle and the target object.

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 the target data is used to calculate the distance to the object, the accuracy of ranging is improved.

It is understandable that the echo processing device includes hardware structures and/or software modules for executing the corresponding functions in order to realize the above functions. Those skilled in the art should easily realize that, in combination with the echo processing method steps of each example 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 executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present application.

The embodiment of the present application can divide the echo processing device into functional modules according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation.

In the case of dividing each functional module according to each function, FIG14 shows a possible structural diagram of an echo processing device involved in the above embodiment, and 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 to execute S801, S802 and S803 in the above method embodiment; the filtering unit 141 is used to support the echo processing device to execute S805 in the above method embodiment.

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

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 The same effect as the above control method can be achieved.

In the several embodiments provided in the present 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 only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, 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.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

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 is essentially 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 the device to perform 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 USB flash drives, mobile hard drives, ROM, RAM, magnetic disks or optical disks.

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.

In another aspect of the present application, a laser radar is provided, comprising a receiver, a transmitter and an echo processing device, wherein the transmitter is used to transmit a laser signal, the receiver is used to receive an echo signal, and the echo processing device is used to perform the relevant steps in the above method embodiment. The echo processing device may be the echo processing device provided in FIG. 4, FIG. 5 or FIG. 6 above.

In another aspect of the present application, a terminal device is provided, comprising: a laser radar, the laser radar is used to perform the relevant steps in the above method embodiment. The terminal device may be the terminal device shown in FIG. 4, FIG. 5 or FIG. 6 above.

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

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 relevant steps in the above method embodiments.

In yet another aspect of the present application, a computer program product comprising instructions is provided. When the computer program product is executed on a computer device, the computer device is enabled to execute the relevant steps in the above method embodiments.

Finally, it should be noted that the above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (17)

An echo processing method, characterized in that it is 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. The method according to claim 1, characterized in that the step of determining the interference noise according to the first position information and the preset offset value comprises: 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. The method according to claim 1 or 2, characterized in that determining a first statistical data having a frequency greater than a preset threshold among a 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. The method according to any one of claims 1 to 3, characterized in that after receiving a plurality of statistical data, the method further comprises: A low-order matched filtering is performed on the plurality of statistical data. The method according to any one of claims 1 to 4, characterized in that after obtaining the target data, the method further comprises: A high-order matched filter is performed on the target data. The method according to any one of claims 1 to 5 is characterized in that the echo processing method is applied in a high reflectivity scene. An echo processing device, characterized in that it is 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 SPADs, and 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. The device according to claim 7, characterized in that the determining unit is further used 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. The device according to claim 7 or 8, characterized in that the determining unit is further used for: 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. The device according to any one of claims 7 to 9, characterized in that the device further comprises: The first filtering unit is used to perform low-order matched filtering on the multiple statistical data. The device according to any one of claims 7 to 10, characterized in that the device further comprises: The second filtering unit is used to perform high-order matched filtering on the target data. The device according to any one of claims 7 to 11 is characterized in that the echo processing device is applied in a high reflectivity scenario. An echo processing device, characterized in that it comprises: 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. A laser radar, characterized in that the laser radar comprises a transmitter, a receiver and an echo processing device as described in any one of claims 7 to 12, the transmitter is used to transmit laser signals, and the receiver is used to receive echo signals. A terminal device, characterized in that the terminal device includes a laser radar, and the laser radar is used to execute the echo processing method as described in any one of claims 1-6. A computer-readable storage medium, characterized in that the computer-readable storage medium includes computer instructions, and when the computer instructions are executed on an echo processing device, the echo processing device executes the echo processing method according to any one of claims 1 to 6. A computer program product comprising instructions, characterized in that when the computer program product is run on a computer device, the computer device is caused to execute the echo processing method according to any one of claims 1 to 6.