Method, device, terminal and storage medium for acquiring point cloud data

Abstract

The present application is applicable to the field of radar technology, and provides a method, device, terminal and storage medium for acquiring point cloud data. The above-mentioned method for acquiring point cloud data specifically includes: acquiring the current ranging data obtained by the radar scanning the target space at multiple emission angles in the current cycle, and the reference ranging data obtained by scanning the target space at the multiple emission angles in the reference cycle; using the current ranging data and the reference ranging data, correcting the value to be corrected in the current ranging data to obtain the distance data of each emission angle in the multiple emission angles; generating the point cloud data of the target space based on the distance data, and extracting the point cloud data of the target object from the point cloud data of the target space. The embodiments of the present application can improve the angular resolution of the radar, and at the same time make the point cloud data of the target object extracted by the terminal more complete and more accurate.

Description

Technical Field

[0001] The present application belongs to the field of radar technology, and in particular relates to a method, device, terminal and storage medium for acquiring point cloud data. Background Art

[0002] Radar can be used to detect targets and determine their spatial position, and is currently widely used in various fields. A rotating scanning mirror lidar is a new type of radar with fixed transmitter and receiver modules. By controlling the rotation of a multifaceted prism, the reflective properties of the mirror are used to deflect and transmit laser light forward, scanning the object being measured. Simultaneously, light reflected by the object is received by a detector through an optical system. After conversion to a photoelectric signal, the back-end acquisition circuit can perform high-speed sampling of the electrical signal and package the resulting echo data for transmission to a host computer.

[0003] Angular resolution is a key indicator of LiDAR's technical parameters. For rotating scanning mirror LiDARs, the reflected light spot from an object moves horizontally across the array of avalanche photodiodes (APDs) as the code disk rotates. Due to the gaps between the APDs, when the light spot hits the gaps, there will be significant crosstalk between adjacent APDs, resulting in the echo data containing multiple valid echoes. Furthermore, when the target object is far from the radar, the light spot may be completely trapped between the gaps, preventing the detector from collecting data.

[0004] To address the above issues, existing technologies generally use the valid part of the collected data for data analysis, which will result in a decrease in the radar angular resolution. Summary of the Invention

[0005] The embodiments of the present application provide a method, device, terminal, and storage medium for acquiring point cloud data, which can improve the angular resolution of the radar and make the point cloud data of the target object extracted by the terminal more complete and more accurate.

[0006] A first aspect of an embodiment of the present application provides a method for acquiring point cloud data, comprising:

[0007] Acquire current ranging data obtained by scanning a target space with a plurality of emission angles by the radar in a current cycle, and reference ranging data obtained by scanning the target space with the plurality of emission angles in a reference cycle;

[0008] Using the current ranging data and the reference ranging data, correcting the value to be corrected in the current ranging data to obtain distance data for each of the multiple emission angles;

[0009] Point cloud data of the target space is generated according to the distance data, and point cloud data of the target object is extracted from the point cloud data of the target space.

[0010] A second aspect of an embodiment of the present application provides a device for acquiring point cloud data, comprising:

[0011] a radar data acquisition unit, configured to acquire current ranging data obtained by scanning a target space with a plurality of emission angles by the radar in a current cycle, and reference ranging data obtained by scanning the target space with the plurality of emission angles in a reference cycle;

[0012] a radar data correction unit, configured to correct a value to be corrected in the current ranging data using the current ranging data and the reference ranging data, to obtain distance data for each of the multiple emission angles;

[0013] The point cloud data acquisition unit is used to generate point cloud data of the target space according to the distance data, and extract point cloud data of the target object from the point cloud data of the target space.

[0014] A third aspect of an embodiment of the present application provides a terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0015] A fourth aspect of an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0016] A fifth aspect of the embodiments of the present application provides a computer program product, which, when run on a terminal, enables the terminal to implement the steps of the method when executing the computer program product.

[0017] In an embodiment of the present application, by obtaining the current ranging data obtained by the radar scanning in the current cycle and the reference ranging data obtained by scanning in the reference cycle, and then using the current ranging data and the reference ranging data to correct the value to be corrected in the current ranging data, the distance data of each emission angle in multiple emission angles is obtained, so that each emission angle of the radar can correspond to a valid distance data. Compared with the method of eliminating abnormal values, the present application can effectively improve the angular resolution of the radar; and, by generating point cloud data of the target space based on these distance data, and extracting the point cloud data of the target object from the point cloud data of the target space, the point cloud data of the target object extracted by the terminal can also be more complete and more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 This is a schematic diagram of a light spot hitting the APD gap provided by an embodiment of the present application;

[0020] Figure 2 This is a schematic diagram of an implementation process for acquiring point cloud data provided by an embodiment of the present application;

[0021] Figure 3 This is a schematic diagram of a specific implementation process for correcting the value to be corrected provided in an embodiment of the present application;

[0022] Figure 4 This is a schematic diagram of a specific implementation process for obtaining initial ranging data provided by an embodiment of the present application;

[0023] Figure 5 This is a schematic diagram of a specific implementation process for obtaining current ranging data provided by an embodiment of the present application;

[0024] Figure 6 This is a schematic diagram of a specific implementation flow of step S502 provided in an embodiment of the present application;

[0025] Figure 7 This is a schematic diagram of emission angle-distance values provided in an embodiment of the present application;

[0026] Figure 8 This is a schematic diagram of the structure of a device for acquiring point cloud data provided in an embodiment of the present application;

[0027] Figure 9 It is a schematic diagram of the structure of the terminal provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of this application more clear, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without making any creative work are protected by this application.

[0029] Among the technical parameters of laser radar, angular resolution is one of the more important indicators. For rotating scanning mirror laser radar, such as Figure 1As shown in the figure, the reflected light spot from an object moves horizontally across the array APD as the code disk rotates. Because there are gaps between the APDs, when the light spot hits the gaps, there will be significant crosstalk between adjacent APDs, resulting in the echo data containing multiple valid echoes. Furthermore, when the target object is far from the radar, the light spot may be completely trapped between the gaps, preventing the detector from collecting data.

[0030] To address the above issues, existing technologies generally eliminate the invalid parts of the collected data and retain the valid parts for data analysis. This will lead to a decrease in the radar's angular resolution, that is, the host computer will only be able to refer to the data of part of the radar's emission angle when performing data processing.

[0031] Therefore, this application proposes a method for obtaining point cloud data. By correcting the values to be corrected in the radar ranging data, the distance data of each emission angle of the radar is obtained, so that the host computer can refer to the data of each emission angle when performing data processing, thereby improving the angular resolution of the radar and making the point cloud data of the target object extracted by the terminal more complete and more accurate.

[0032] In order to illustrate the technical solution of the present application, specific embodiments are provided below.

[0033] Figure 2 A schematic diagram of the implementation process of a method for acquiring point cloud data provided in an embodiment of the present application is shown. The method can be applied to a terminal and is suitable for situations where it is necessary to improve the radar angular resolution and improve the integrity and accuracy of point cloud data.

[0034] The terminal may be a radar, and the method may be implemented by a field programmable gate array (FPGA) chip, an ARM (Advanced RISC Machines) chip, or other chip within the radar. The terminal may also be a host computer connected to the radar, specifically a smart device such as a smartphone, tablet, computer, or server.

[0035] Specifically, the above method for acquiring point cloud data may include the following steps S201 to S203.

[0036] Step S201: obtaining current ranging data obtained by scanning the target space at multiple transmission angles in a current cycle, and reference ranging data obtained by scanning the target space at multiple transmission angles in a reference cycle.

[0037] In the embodiments of the present application, the radar may be a rotating scanning mirror laser radar or other radar that is prone to generating abnormal value data. The target space may refer to the scanning range of the radar.

[0038] In the embodiments of the present application, the terminal can scan the target space over multiple scanning cycles. During each scanning cycle, the radar will transmit laser light at each of multiple emission angles to complete the scan. By acquiring the echo data corresponding to each emission angle, the terminal can determine the ranging data of the radar for each scanning cycle. The ranging data refers to the relative distance between the target object in the target space and the radar. The target object can refer to an object that is stationary in the target space.

[0039] For example, a rotating scanning mirror lidar uses a motor to control the code disk, which in turn controls the rotation of the multi-faceted prism, during the current cycle. Different code disk degrees correspond to a specific emission angle. After traversing all code disk degrees, the detector detects the echo data corresponding to each emission angle. The terminal analyzes this echo data to obtain the current ranging data.

[0040] It should be noted that the current cycle may be any scan cycle other than the first scan cycle of the radar, and the reference cycle may be any scan cycle completed before the current cycle. In some embodiments of the present application, the radar may scan periodically at a preset frequency, and the reference cycle may be the scan cycle before the current cycle.

[0041] Step S202: using the current distance measurement data and the reference distance measurement data, correct the value to be corrected in the current distance measurement data to obtain distance data for each of the multiple emission angles.

[0042] In an embodiment of the present application, the terminal can determine whether there is a value to be corrected in the current ranging data based on the current ranging data and the reference ranging data, and correct the value to be corrected therein to obtain distance data for each of the multiple transmission angles. The value to be corrected can refer to an abnormal value or a default value in the current ranging data.

[0043] Research has found that when the light spot only hits a certain APD, the radar can collect the echo signal of the channel corresponding to the APD; when the light spot completely hits the APD gap, the radar will not be able to collect the echo signal; when the light spot hits multiple APDs, the radar will collect the echo signal of the channel corresponding to each APD in the multiple APDs, and then the crosstalk problem occurs. In some embodiments, the above-mentioned value to be corrected can specifically refer to the ranging data corresponding to the emission angle used when the radar did not collect the echo signal in the current ranging data, that is, the current ranging data corresponding to when the light spot completely hits the APD gap. In some embodiments, the above-mentioned value to be corrected can also specifically refer to the ranging data corresponding to the emission angle used when the radar collected multiple echo signals in the current ranging data, that is, the current ranging data corresponding to when the light spot hits multiple APDs.

[0044] Specifically, such as Figure 3 As shown, the above correction process may specifically include the following steps S301 to S304.

[0045] Step S301: Filter out values to be corrected and values not to be corrected from current distance measurement data.

[0046] Specifically, the terminal may first filter out the to-be-corrected values from the current ranging data, and then use the other current ranging data except the to-be-corrected values as the non-to-be-corrected values.

[0047] Step S302: The emission angle corresponding to the value to be corrected is used as the emission angle to be corrected, and the emission angle adjacent to the emission angle to be corrected is used as the reference emission angle.

[0048] That is, the reference emission angle is the emission angle before or next to the emission angle to be corrected.

[0049] Step S303 , correcting the value to be corrected according to the ranging data of the emission angle to be corrected and the reference emission angle in the reference ranging data, and the ranging data of the emission angle to be corrected and the reference emission angle in the current ranging data to obtain a corrected value.

[0050] In some embodiments of the present application, if the current ranging data corresponding to any emission angle in the current ranging data is a null value, it indicates that the reflected light spot of the laser emitted at that emission angle precisely hits the gap between the APDs. Based on this, the terminal may use this null value as the value to be corrected. In this case, the terminal may determine the correction value corresponding to the value to be corrected based on the ranging data of the emission angle immediately following the emission angle to be corrected in the reference ranging data, and the ranging data of the emission angle immediately preceding the emission angle to be corrected in the current ranging data.

[0051] Assume that the reference distance data is Indicates that the current distance measurement data is Indicates, where 0.2, 0.4, and 0.6 represent the emission angles respectively. Is a null value, that is is the value to be corrected, the terminal can and Determine the correction value Wherein, α1∈[0,1], α2∈[0,1] and α1+α2=1. The specific values of α1 and α2 can be adjusted according to actual conditions. Preferably, α1∈[0.3,0.7] and α2∈[0.3,0.7].

[0052] In other embodiments, it is also possible to determine whether the current ranging data corresponding to any emission angle is a value to be corrected based on the ranging data of any emission angle in the current ranging data and the ranging data of the same emission angle and adjacent emission angles in the reference ranging data.

[0053] Specifically, if the difference between the ranging data of a certain emission angle in the current ranging data and the ranging data of the emission angle next to the emission angle in the reference ranging data is less than or equal to the first threshold H1, and the difference between the ranging data of the emission angle in the current ranging data and the reference ranging data of the emission angle before the emission angle in the reference ranging data is greater than or equal to the second threshold H2, it indicates that the relative distance between the target object and the radar in the target space has suddenly changed. At this time, it can be confirmed that the ranging data of the emission angle in the current ranging data is the value to be corrected.

[0054] At this time, the terminal may determine the correction value corresponding to the value to be corrected based on the ranging data of the emission angle next to the emission angle to be corrected in the reference ranging data and the ranging data of the emission angle to be corrected in the current ranging data.

[0055] Continuing with the above example, if conform to and Then the terminal can confirm d0.42 as the value to be corrected. Among them, ABS() refers to the absolute value. Then, according to and The terminal can determine the correction value Among them, α3∈[0,1], α4∈[0,1] and α3+α4=1. Similarly, the specific values of α3 and α4 can be adjusted according to actual conditions. Preferably, α3∈[0.3,0.7] and α4∈[0.3,0.7].

[0056] If the difference between the ranging data of a certain emission angle in the current ranging data and the ranging data of the next emission angle in the current ranging data is less than or equal to the third threshold H3, and the difference between the ranging data of the emission angle in the current ranging data and the reference ranging data of the next emission angle in the reference ranging data is greater than or equal to the fourth threshold H4, it indicates that the relative distance between the target object in the target space and the radar changes in different scanning cycles. At this time, it can be confirmed that the ranging data of the emission angle in the current ranging data is the value to be corrected.

[0057] At this time, the terminal may determine the correction value corresponding to the value to be corrected based on the ranging data of the previous emission angle of the emission angle to be corrected in the current ranging data and the ranging data of the emission angle to be corrected in the current ranging data.

[0058] Continuing with the above example, if conform to and Then the terminal can confirm d0.42 as the value to be corrected. Then, based on d0.22 and d0.42, the terminal can determine the correction value Among them, α5∈[0,1], α6∈[0,1] and α5+α6=1. Similarly, the specific values of α5 and α6 can be adjusted according to actual conditions. Preferably, α5∈[0.3,0.7] and α6∈[0.3,0.7].

[0059] In addition, taking into account the possibility of a slope phenomenon occurring during radar ranging, in order to reduce the impact of the slope phenomenon on the accuracy of the ranging data, in some embodiments of the present application, if the difference between the ranging data of a certain emission angle in the current ranging data and the ranging data of the emission angle in the reference ranging data is less than or equal to the fifth threshold H5, it indicates that a slope phenomenon occurs during the radar ranging process. Based on this, the terminal can confirm that the ranging data of the emission angle in the current ranging data is the value to be corrected.

[0060] At this time, the terminal may determine a correction value corresponding to the value to be corrected based on the ranging data of the emission angle to be corrected in the current ranging data and the ranging data of the emission angle to be corrected in the reference ranging data.

[0061] Continuing with the above example, if conform to The terminal can Confirm it as the value to be corrected. Then, according to and The terminal can determine the correction value Among them, α7∈[0,1], α8∈[0,1] and α7+α8=1. Similarly, the specific values of α7 and α8 can be adjusted according to actual conditions. Preferably, α7∈[0.3,0.7] and α8∈[0.3,0.7].

[0062] In other embodiments of the present application, if the difference between the ranging data of a certain emission angle in the current ranging data and the ranging data of the previous emission angle to be corrected in the current ranging data is less than or equal to the sixth threshold H6, it also indicates that a slope phenomenon occurs in the radar ranging process. Based on this, the terminal can confirm that the ranging data of the emission angle in the current ranging data is the value to be corrected.

[0063] At this time, the terminal may determine the correction value corresponding to the value to be corrected based on the ranging data of the emission angle to be corrected in the current ranging data and the ranging data of the emission angle before the emission angle to be corrected in the current ranging data.

[0064] Continuing with the above example, if conform to The terminal can Confirm it as the value to be corrected. Then, according to and The terminal can determine the correction value Among them, α9∈[0,1], α 10 ∈[0,1] and α9+α 10 = 1. Similarly, α9 and α 10 The specific value can be adjusted according to the actual situation. Preferably, α9∈[0.3,0.7] and α 10 ∈

[0065] [0.3,0.7].

[0066] It should be noted that the above-mentioned first threshold H1, second threshold H2, third threshold H3, fourth threshold H4, fifth threshold H5 and sixth threshold H6 can be adjusted according to actual conditions, for example, according to the ranging accuracy of the radar.

[0067] In some embodiments of the present application, the first threshold H1, the third threshold H3, the fifth threshold H5 and the sixth threshold H6 may be 60 mm; the second threshold H2 and the fourth threshold H4 may be 120 mm.

[0068] In other embodiments of the present application, if the number of echo signal channels corresponding to the current ranging data at a certain emission angle exceeds a preset value, it indicates that the reflected speckle pattern of the laser emitted by the radar at that emission angle has struck multiple APDs. Based on this, the terminal may use the current ranging data corresponding to that emission angle as a value to be corrected. In this case, the terminal may correct the current ranging data corresponding to that emission angle based on the echo signals from multiple channels. For example, the terminal may filter out the target echo signal from the echo signals from multiple channels and calculate the corrected current ranging data based on the target echo signal.

[0069] The above-mentioned preset number value can be set according to actual conditions, and can generally be set to 1.

[0070] It should be noted that when the above-mentioned terminal determines the value to be corrected and corrects the value to be corrected, it can adopt any one or more of the aforementioned methods in sequence, and when the terminal adopts the aforementioned multiple methods to determine the value to be corrected and correct the value to be corrected, the execution order of each method can be adjusted according to actual conditions.

[0071] Step S304: taking the corrected value and the value not to be corrected as distance data.

[0072] In some embodiments of the present application, based on the aforementioned method, the value to be corrected in the current ranging data will be corrected to a correction value. At this time, the correction value and the non-corrected value are combined to obtain the distance data of each emission angle in multiple emission angles.

[0073] Step S203 : generating point cloud data of the target space according to the distance data, and extracting point cloud data of the target object from the point cloud data of the target space.

[0074] In the embodiments of the present application, based on the aforementioned distance data, the terminal can generate point cloud data for each point in the target space and perform point cloud segmentation using the point cloud data to extract the point cloud data of the target object from the point cloud data of the target space. The point cloud data of the target object can represent the distance between each point on the target object surface and the radar. In practical applications, it can be used for target recognition and detection, 3D reconstruction, simultaneous localization and mapping (SLAM), and other applications.

[0075] It should be noted that the specific method of the above-mentioned point cloud segmentation can be implemented by using a random sample consensus (RANSAC) algorithm, a point cloud segmentation algorithm based on proximity information, a Euclidean algorithm, or other point cloud segmentation algorithms. It can also be implemented through a deep learning network for processing point clouds, for example, it can be implemented through a PointNet neural network, and this application does not impose any restrictions on this.

[0076] In an embodiment of the present application, by obtaining the current ranging data obtained by the radar scanning in the current cycle and the reference ranging data obtained by scanning in the reference cycle, and then using the current ranging data and the reference ranging data to correct the value to be corrected in the current ranging data, the distance data of each emission angle in multiple emission angles is obtained, so that each emission angle of the radar can correspond to a valid distance data. Compared with the method of eliminating abnormal values, the present application can effectively improve the angular resolution of the radar; and, by generating point cloud data of the target space based on these distance data, and extracting the point cloud data of the target object from the point cloud data of the target space, the point cloud data of the target object extracted by the terminal can also be more complete and more accurate.

[0077] In order to make the point cloud data smoother, after extracting the point cloud data of the target object from the point cloud data of the target space, the terminal can perform bilateral filtering on the point cloud data of the target object to reduce the discreteness of the point cloud data and obtain smooth point cloud data.

[0078] Specifically, the terminal can use the formula Complete the above bilateral filtering process, where p i Represents a point in the point cloud data, Represents the point cloud data after processing, n i represents the normal vector of the point, and λ is the bilateral filter factor.

[0079] In some embodiments of the present application, the above bilateral filter factor can be obtained by the formula Where, N k (p i ) represents the point cloud p i The point set in the K domain, W c () represents the weight function of the spatial domain of the bilateral filter function, W s () represents the weight function of the frequency domain of the bilateral filter function,<a,b> represents the inner product of a and b.

[0080] In the implementation manner of the present application, the above-mentioned method for obtaining the current ranging data can be selected according to actual conditions.

[0081] In some embodiments of the present application, the terminal may obtain echo data collected by the radar, and select a corresponding strategy to calculate ranging data according to the number of channels of the echo signal in the echo data.

[0082] Specifically, when the number of channels of the echo signal corresponding to a certain emission angle in the echo data is 0, it means that the reflected light spot of the laser emitted by the radar through this emission angle just hits the APD gap. At this time, the terminal can replace the initial ranging data of the emission angle with a null value and use the initial ranging data as the current ranging data corresponding to the emission angle.

[0083] When the number of channels of the echo signal corresponding to a certain emission angle in the echo data is 1, it means that the reflected speckle of the laser emitted by the radar at this emission angle only hits one APD. At this time, the terminal can determine the waveform characteristics of the echo signal and use the waveform characteristics of the echo signal to determine the initial ranging data for the emission angle, and use the initial ranging data as the current ranging data corresponding to the emission angle.

[0084] Specifically, in some embodiments of the present application, the terminal may correct the leading edge value of the echo signal using the pulse width of the echo signal, and calculate the initial ranging distance based on the corrected leading edge value.

[0085] Because some waveforms in the echo signal are incomplete, after identifying the leading edge value of the echo signal, the terminal can correct it based on the pulse width to obtain an accurate leading edge value. It then calculates the round-trip duration of the laser pulse during the measurement process based on the leading edge values of two adjacent waveforms. Based on this duration and the propagation speed of the laser in air, the initial ranging distance can be calculated.

[0086] If the number of channels in the echo data corresponding to a certain emission angle is greater than one, it indicates that the reflected spot of the laser emitted by the radar at that emission angle hits multiple APDs. In this case, the terminal can calculate initial ranging data based on the echo signals from multiple channels and use this initial ranging data as the current ranging data for that emission angle. For example, the terminal can calculate the average waveform characteristics of the echo signals from multiple channels and use this average waveform characteristic to calculate the initial ranging data.

[0087] In order to improve the accuracy of the ranging data, in some embodiments of the present application, if the number of channels of the echo signal corresponding to a certain emission angle in the echo data is greater than 1, the above-mentioned terminal can also analyze the target echo signal whose waveform characteristics in the echo data collected by the radar meet the characteristic conditions to obtain initial ranging data.

[0088] Specifically, such as Figure 4 As shown, the process of acquiring the initial ranging data may include the following steps S401 to S404.

[0089] Step S401: Acquire echo data collected by the radar.

[0090] The echo data is based on reflected light from the target space. The reflected light can be laser beams emitted by the radar at multiple emission angles during the current cycle, reflected from the target space. When objects in the target space reflect the laser light, the detector captures the reflected light and generates echo data.

[0091] Specifically, the echo data may be represented as waveform data of time-voltage values.

[0092] Step S402: determining the waveform characteristics of the echo signals of each channel in the echo data.

[0093] The waveform data may include the leading edge value, pulse width, peak value, waveform area, etc. of the echo signal of each channel.

[0094] Specifically, in some embodiments, the waveform area can be calculated using the waveform integration method. Solve, where P(t) is the area of the waveform, w(t) is the voltage, and t is time.

[0095] In other embodiments, the waveform area may refer to the area enclosed by the waveform curve corresponding to the voltage value from the initial voltage value to the final voltage value and the isobars corresponding to the preset voltage value. The initial voltage value, the final voltage value, and the preset voltage value may be adjusted according to actual conditions. Considering that the actual waveform is often a discrete waveform, in some embodiments of the present application, the waveform area may be expressed as Instead, where Vth is the initial voltage value, x' is the time value corresponding to the initial voltage value, x1 is the sampling time closest to x', and x n ′ is the time value corresponding to the final voltage value, x n For x n ′The closest sampling time, x1 and x n The sampling time between them is expressed as x 2， …, x n-1 Indicates that x1 to x n The corresponding voltage values are y1 to y n .

[0096] Step S403: Determine, from the echo data, a target echo signal whose waveform characteristics meet the characteristic conditions.

[0097] In some embodiments of the present application, to avoid interference with ranging caused by crosstalk, the terminal can analyze the echo data of any channel to obtain ranging data. However, the accuracy of the echo data from each channel varies. To ensure higher accuracy of the subsequently obtained ranging data, the present application can determine from the echo data the target echo signal whose waveform characteristics meet the characteristic conditions.

[0098] Specifically, the characteristic condition may refer to the largest waveform area, that is, the terminal may determine the echo signal with the largest echo area as the target echo signal.

[0099] Step S404: Determine initial ranging data using the waveform characteristics of the target echo signal.

[0100] The specific implementation method of determining the initial ranging data using the waveform characteristics of the target echo signal can refer to the method of determining the initial ranging data when the number of channels of the echo signal is 1, which will not be described in detail in this application.

[0101] In an embodiment of the present application, a target echo signal whose waveform characteristics meet characteristic conditions is determined from the echo data, and the initial ranging data is determined by using the waveform characteristics of the target echo signal. When the radar collects echo signals from multiple channels, that is, when the light spot hits multiple APDs and causes crosstalk, the ranging data can be obtained based on the analysis of the echo signal with higher accuracy, thereby avoiding the interference of crosstalk on subsequent data processing, and thus improving the accuracy of the obtained point cloud data.

[0102] It should be noted that, in some embodiments of the present application, the terminal may use the initial ranging data as the aforementioned current ranging data, and obtain reference ranging data obtained in the same manner, and then execute steps S202 and S203 to obtain point cloud data of the target object.

[0103] In other implementations of the present application, the terminal may further process the initial ranging data and use the processed data as ranging data used in subsequent steps S202 and S203.

[0104] The following describes a process for obtaining the current ranging data using a specific embodiment. The reference ranging data or ranging data corresponding to other scanning periods may refer to the implementation method of the current ranging data.

[0105] Specifically, the radar may include a control element and an optical element, wherein the control element is used to control the emission angle of the radar so that the laser emitted by the radar is emitted to the target space through different reflection surfaces of the optical element.

[0106] Among them, the control element can be a code disk of a rotating scanning mirror laser radar, and the optical element can be a multi-faceted prism of a rotating scanning mirror laser radar.

[0107] Correspondingly, such as Figure 5 As shown, the current process of acquiring ranging data may include the following steps S501 to S502.

[0108] Step S501: Acquire initial ranging data obtained by the radar scanning the target space at multiple emission angles in the current cycle.

[0109] Specifically, the method of obtaining the initial ranging data can be found in Figure 4 The specific description of this application will not be repeated in this application.

[0110] Step S502: correcting the initial distance measurement data according to the control parameters of the control element when collecting the initial distance measurement data to obtain current distance measurement data.

[0111] In some embodiments of the present application, the control unit can make the laser emitted by the radar be emitted to the target space through different reflection surfaces of the optical element according to different control parameters.

[0112] Specifically, the above control parameter may refer to the count value of the code disk. Figure 6 As shown, the above step S502 may specifically include the following steps S601 to S603.

[0113] Step S601: Determine, based on the degree range of the count value, the target reflection surface that the laser emitted by the radar passes through when the control element collects the initial ranging data.

[0114] Specifically, different reflective surfaces of an optical element correspond to different code disk count ranges. For example, the first reflective surface of a hexagonal prism corresponds to a count range of 0° to 60°, the second to 60° to 120°, and so on. Based on this, the terminal can determine the target reflective surface that the laser passed through when the control element collected the initial ranging data based on the range of the count value.

[0115] Step S602: Obtain the accuracy difference between the target reflecting surface and the reference reflecting surface.

[0116] Wherein, the reference reflection surface is any reflection surface of the optical element.

[0117] In some embodiments of the present application, a terminal may obtain first sample ranging data obtained by scanning a sample object with a radar at an emission angle corresponding to a target reflecting surface, and second sample ranging data obtained by scanning the sample object with a radar at an emission angle corresponding to a reference reflecting surface, where the sample object is stationary. The terminal may then calculate the accuracy difference between the target reflecting surface and the reference reflecting surface based on the first sample ranging data and the second sample ranging data.

[0118] Specifically, the terminal may calculate a first average value of the first sample ranging data and a second average value of the second sample ranging data, and use the difference between the first average value and the second average value as the accuracy difference between the target reflecting surface and the reference reflecting surface.

[0119] For example, Figure 7 As shown in the figure, the horizontal axis represents the emission angle, the vertical axis represents the distance value, and each star point can represent a sample ranging data. Assuming that the star points near the horizontal axis 0 are the first sample ranging data, and the star points near the horizontal axis 50 are the second ranging data, the terminal can calculate the first average value of the distance values corresponding to the star points near the horizontal axis 0, and the second average value of the distance values corresponding to the star points near the horizontal axis 50, and use the difference between the first average value and the second average value as the accuracy difference between the target reflecting surface and the reference reflecting surface.

[0120] Step S603: Based on the accuracy difference, the initial distance measurement data is corrected to obtain current distance measurement data.

[0121] Specifically, each distance measurement data in the initial distance measurement data may be added to the precision difference to obtain the current distance measurement data corresponding to each initial distance measurement data.

[0122] In the implementation mode of the present application, since the ranging accuracy of different mirror surfaces is different, the terminal corrects the initial ranging data according to the control parameters so that the ranging data measured on different surfaces can be unified to a benchmark, so that in the subsequent correction process, the value to be corrected will not be misjudged due to the existence of accuracy difference, thereby improving the accuracy of the point cloud data.

[0123] It should be noted that, for the sake of simplicity of description, the aforementioned method embodiments are all expressed as a series of action combinations. However, those skilled in the art should be aware that this application is not limited to the described order of actions, because according to this application, certain steps can be performed in other orders.

[0124] like Figure 8 The figure shows a structural diagram of a point cloud data acquisition device 800 provided in an embodiment of the present application, wherein the point cloud data acquisition device 800 is configured on a terminal.

[0125] Specifically, the point cloud data acquisition device 800 may include:

[0126] The radar data acquisition unit 801 is configured to acquire current ranging data obtained by scanning a target space with a plurality of transmission angles during a current period, and reference ranging data obtained by scanning the target space with the plurality of transmission angles during a reference period.

[0127] a radar data correction unit 802 configured to correct a value to be corrected in the current ranging data using the current ranging data and the reference ranging data, to obtain distance data for each of the multiple emission angles;

[0128] The point cloud data acquisition unit 803 is configured to generate point cloud data of the target space according to the distance data, and extract point cloud data of the target object from the point cloud data of the target space.

[0129] In some embodiments of the present application, the radar data correction unit 802 can be specifically used to: filter out a value to be corrected and a value not to be corrected from the current ranging data; use the emission angle corresponding to the value to be corrected as the emission angle to be corrected, and use the emission angle adjacent to the emission angle to be corrected as the reference emission angle; correct the value to be corrected according to the ranging data of the emission angle to be corrected and the reference emission angle in the reference ranging data, and the ranging data of the emission angle to be corrected and the reference emission angle in the current ranging data to obtain a corrected value; and use the corrected value and the value not to be corrected as the distance data.

[0130] In some embodiments of the present application, the value to be corrected may include ranging data in the current ranging data corresponding to the emission angle used when the radar does not collect an echo signal.

[0131] In some embodiments of the present application, the radar data acquisition unit 801 may be specifically configured to: obtain initial ranging data obtained by the radar scanning the target space at the multiple emission angles in the current period; and correct the initial ranging data according to control parameters of the control element of the radar when the initial ranging data is collected to obtain the current ranging data.

[0132] In some embodiments of the present application, the control parameter is a count value of a control element; the radar data acquisition unit 801 may be specifically configured to: determine, based on a degree range of the count value, a target reflection surface through which the laser emitted by the radar passes when the control element collects the initial ranging data; obtain an accuracy difference between the target reflection surface and a reference reflection surface, where the reference reflection surface is any reflection surface of an optical element; and correct the initial ranging data based on the accuracy difference to obtain the current ranging data.

[0133] In some embodiments of the present application, the radar data acquisition unit 801 may be specifically configured to: acquire first sample ranging data obtained by scanning a sample object with a radar at an emission angle corresponding to the target reflecting surface, where the sample object is stationary; acquire second sample ranging data obtained by scanning the sample object with a radar at an emission angle corresponding to the reference reflecting surface; and calculate, based on the first sample ranging data and the second sample ranging data, an accuracy difference between the target reflecting surface and the reference reflecting surface.

[0134] In some embodiments of the present application, the above-mentioned radar data acquisition unit 801 can be specifically used to: obtain echo data collected by the radar, the echo data is echo data obtained based on the reflected light of the target space, the reflected light is the light beam obtained after the laser emitted by the radar at the multiple emission angles during the current cycle is reflected by the target space, and the echo data includes echo signals of multiple channels; determine the waveform characteristics of the echo signals of each channel in the echo data; determine from the echo data the target echo signal whose waveform characteristics meet the characteristic conditions; and determine the initial ranging data using the waveform characteristics of the target echo signal.

[0135] In some embodiments of the present application, the point cloud data acquisition device 800 may further include a bilateral filtering processing unit for performing bilateral filtering on the point cloud data of the target object.

[0136] It should be noted that for the convenience and simplicity of description, the specific working process of the point cloud data acquisition device 800 can be referred to Figures 1 to 7 The corresponding process of the method will not be described in detail here.

[0137] like Figure 9 The figure shows a schematic diagram of a terminal provided in an embodiment of the present application. The terminal 9 may include: a processor 90, a memory 91, and a computer program 92 stored in the memory 91 and executable on the processor 90, such as a point cloud data acquisition program. When the processor 90 executes the computer program 92, the steps in the above-mentioned point cloud data acquisition method embodiments are implemented, such as Figure 1 Alternatively, when the processor 90 executes the computer program 92, the functions of the modules / units in the above-mentioned device embodiments are realized, for example, Figure 8 The radar data acquisition unit 801, the radar data correction unit 802 and the point cloud data acquisition unit 803 are shown.

[0138] The computer program may be divided into one or more modules / units, which are stored in the memory 91 and executed by the processor 90 to implement the present application. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, and the instruction segments are used to describe the execution process of the computer program in the terminal.

[0139] For example, the computer program may be divided into: a radar data acquisition unit, a radar data correction unit, and a point cloud data acquisition unit.

[0140] The specific functions of each unit are as follows: a radar data acquisition unit, configured to acquire current ranging data obtained by scanning the target space at multiple emission angles during a current cycle, and reference ranging data obtained by scanning the target space at the multiple emission angles during a reference cycle; a radar data correction unit, configured to correct the to-be-corrected value in the current ranging data using the current ranging data and the reference ranging data, to obtain distance data for each of the multiple emission angles; and a point cloud data acquisition unit, configured to generate point cloud data of the target space based on the distance data, and to extract point cloud data of the target object from the point cloud data of the target space.

[0141] The terminal may include, but is not limited to, a processor 90 and a memory 91. Those skilled in the art will understand that Figure 9 It is only an example of a terminal and does not constitute a limitation on the terminal. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the terminal may also include input and output devices, network access devices, buses, etc.

[0142] The processor 90 may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), off-the-shelf programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0143] The memory 91 may be an internal storage unit of the terminal, such as a hard disk or memory of the terminal. The memory 91 may also be an external storage device of the terminal, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash memory card, etc. equipped on the terminal. Furthermore, the memory 91 may include both an internal storage unit of the terminal and an external storage device. The memory 91 is used to store the computer program and other programs and data required by the terminal. The memory 91 may also be used to temporarily store data that has been output or is about to be output.

[0144] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0145] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0146] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software 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 beyond the scope of this application.

[0147] In the embodiments provided in this application, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. 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 system, 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.

[0148] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0149] 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.

[0150] If the integrated module / 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 computer-readable storage medium. Based on this understanding, the present application implements all or part of the process in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by the processor, it can implement the steps of the above-mentioned various method embodiments. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0151] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A method for acquiring point cloud data, characterized in that: include: Acquire current ranging data obtained by scanning a target space with a plurality of emission angles by the radar in a current cycle, and reference ranging data obtained by scanning the target space with the plurality of emission angles in a reference cycle; Using the current ranging data and the reference ranging data, correcting the value to be corrected in the current ranging data to obtain distance data for each of the multiple emission angles; generating point cloud data of the target space according to the distance data, and extracting point cloud data of the target object from the point cloud data of the target space; The method of correcting the to-be-corrected value in the current ranging data by using the current ranging data and the reference ranging data to obtain distance data for each of the multiple emission angles includes: filtering out the to-be-corrected value and the non-to-be-corrected value from the current ranging data; The emission angle corresponding to the value to be corrected is used as the emission angle to be corrected, and the emission angle adjacent to the emission angle to be corrected is used as the reference emission angle; the value to be corrected is corrected according to the ranging data of the emission angle to be corrected and the reference emission angle in the reference ranging data, and the ranging data of the emission angle to be corrected and the reference emission angle in the current ranging data to obtain a corrected value; and the corrected value and the value not to be corrected are used as the distance data.

2. The method for acquiring point cloud data according to claim 1, wherein: The value to be corrected includes ranging data in the current ranging data corresponding to the emission angle used when the radar does not collect an echo signal.

3. The method for acquiring point cloud data according to claim 1 or 2, wherein: The acquiring of current ranging data obtained by the radar scanning the target space at multiple emission angles in the current cycle includes: Acquire initial ranging data obtained by the radar scanning the target space at the multiple emission angles in the current cycle; The initial ranging data is corrected according to the control parameters of the control element of the radar when the initial ranging data is collected to obtain the current ranging data.

4. The method for acquiring point cloud data according to claim 3, wherein: The control parameter is a count value of the control element; The step of correcting the initial ranging data according to the control parameters of the control element when the initial ranging data is collected to obtain the current ranging data includes: determining, based on the degree range of the count value, a target reflection surface through which the laser emitted by the radar passes when the control element collects the initial ranging data; Obtaining an accuracy difference between the target reflective surface and a reference reflective surface, where the reference reflective surface is any reflective surface of an optical element; Based on the accuracy difference, the initial distance measurement data is corrected to obtain the current distance measurement data.

5. The method for acquiring point cloud data according to claim 4, wherein: The obtaining of the accuracy difference between the target reflecting surface and the reference reflecting surface includes: Acquire first sample ranging data obtained by scanning a sample object with a radar at an emission angle corresponding to the target reflecting surface, where the sample object is in a stationary state; Acquire second sample ranging data obtained by scanning the sample object with a radar at an emission angle corresponding to the reference reflecting surface; The accuracy difference between the target reflecting surface and the reference reflecting surface is calculated based on the first sample ranging data and the second sample ranging data.

6. The method for acquiring point cloud data according to claim 3, wherein: The acquiring initial ranging data obtained by the radar scanning the target space at the multiple emission angles in the current cycle includes: Acquiring echo data collected by the radar, the echo data being echo data obtained based on reflected light from the target space, the reflected light being a beam of laser light emitted by the radar at the multiple emission angles during the current cycle and reflected from the target space, and the echo data including echo signals from multiple channels; Determining waveform characteristics of echo signals of each channel in the echo data; Determining, from the echo data, a target echo signal whose waveform characteristics satisfy characteristic conditions; The initial ranging data is determined using the waveform characteristics of the target echo signal.

7. The method for acquiring point cloud data according to claim 1 or 2, wherein: After extracting the point cloud data of the target object from the point cloud data of the target space, the method includes: Perform bilateral filtering on the point cloud data of the target object.

8. A device for acquiring point cloud data, characterized in that: include: a radar data acquisition unit, configured to acquire current ranging data obtained by scanning a target space with a plurality of emission angles by the radar in a current cycle, and reference ranging data obtained by scanning the target space with the plurality of emission angles in a reference cycle; a radar data correction unit, configured to correct a value to be corrected in the current ranging data using the current ranging data and the reference ranging data, to obtain distance data for each of the multiple emission angles; a point cloud data acquisition unit, configured to generate point cloud data of the target space according to the distance data, and extract point cloud data of the target object from the point cloud data of the target space; The radar data correction unit is specifically configured to: filter out a value to be corrected and a value not to be corrected from the current ranging data; use the emission angle corresponding to the value to be corrected as the emission angle to be corrected, and use the emission angle adjacent to the emission angle to be corrected as the reference emission angle; correct the value to be corrected based on ranging data of the emission angle to be corrected and the reference emission angle in the reference ranging data, and ranging data of the emission angle to be corrected and the reference emission angle in the current ranging data to obtain a corrected value; and use the corrected value and the value not to be corrected as the distance data.

9. A terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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