Detection threshold determination method, related device and computer storage medium

Abstract

The invention discloses a detection threshold determination method, a related device and a computer storage medium, and the method comprises the steps: determining a detection threshold of a working region of a next scanning period based on the number of noise echoes of a blanking region of an ith scanning period and a detection threshold of a working region of the ith scanning period, the detection threshold is adaptively adjusted in real time according to the current noise state, so that the accuracy of related information of each object in a target scene measured by the laser radar is improved.

Description

Technical Field

[0001] The present application relates to the field of laser radar technology, and in particular to a detection threshold determination method, related devices and computer storage media. Background Art

[0002] LiDAR determines relevant information about objects in a target scene, such as distance and height, by emitting photon detection signals. LiDAR can convert the acquired target echo signal (the echo signal corresponding to the detection signal) into an electrical signal and determine relevant information based on the electrical signal.

[0003] When the amplitude of the echo signal detected by the photoelectric conversion module of the laser radar exceeds the detection threshold, the detection threshold can be used to sample the target echo signal and output the sampled signal to the signal processing module; when the amplitude of the echo signal is lower than the detection threshold, the detection threshold cannot be used to sample the target echo signal. Summary of the invention

[0004] The embodiments of the present application provide a detection threshold determination method, a related device, and a computer storage medium.

[0005] In a first aspect, an embodiment of the present application provides a detection threshold method, the method comprising:

[0006] Obtain the number of noise echoes in the blanking area of ​​the i-th scanning cycle;

[0007] Determine the detection threshold of the working area of ​​the (i+1)th scanning cycle according to the number of noise echoes and the detection threshold of the working area of ​​the i-th scanning cycle;

[0008] Each scanning cycle includes a working area and a blanking area; the working area represents the scanning time period of the scanning cycle, and the blanking area represents the retrace time period of the scanning cycle; i is a positive integer.

[0009] In a second aspect, an embodiment of the present application provides a detection threshold device, the device comprising:

[0010] An acquisition module, used for acquiring the number of noise echoes in the blanking area of ​​the i-th scanning cycle;

[0011] A determination module, used to determine the detection threshold of the working area of ​​the (i+1)th scanning cycle according to the number of noise echoes and the detection threshold of the working area of ​​the i-th scanning cycle;

[0012] Each scanning cycle includes a working area and a blanking area; the working area represents the scanning time period of the scanning cycle, and the blanking area represents the retrace time period of the scanning cycle; i is a positive integer.

[0013] In a third aspect, an embodiment of the present application provides a computer storage medium, wherein the computer storage medium stores a plurality of instructions, wherein the instructions are suitable for being loaded by a processor and executing the above-mentioned method steps.

[0014] In a fourth aspect, an embodiment of the present application provides a terminal, which may include: a processor and a memory;

[0015] The memory stores a computer program, and the computer program is suitable for being loaded by the processor and executing the above method steps.

[0016] The beneficial effects brought about by the technical solutions provided by some embodiments of the present application include at least:

[0017] In the embodiment of the present application, the detection threshold of the working area of ​​the next scanning cycle can be determined by the number of noise echoes in the blanking area of ​​the ith scanning cycle and the detection threshold of the working area of ​​the ith scanning cycle, thereby realizing adaptive real-time adjustment of the detection threshold according to the current noise state, thereby achieving the purpose of improving the accuracy of relevant information of each object in the target scene measured by the laser radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. 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 paying creative work.

[0019] Figure 1A A schematic diagram of an echo signal detection waveform provided in an embodiment of the present application;

[0020] Figure 1B An application scenario diagram of the detection threshold method provided in an embodiment of the present application;

[0021] Figure 2 A flowchart of a detection threshold method provided in an embodiment of the present application;

[0022] Figure 3A A schematic flow chart of another detection threshold method provided in an embodiment of the present application;

[0023] Figure 3B A schematic diagram of dividing a scanning area provided in an embodiment of the present application;

[0024] Figure 3C A schematic diagram of vertical scanning angle waveform division provided in an embodiment of the present application;

[0025] Figure 3D A schematic diagram of the horizontal scanning angle waveform division provided in an embodiment of the present application;

[0026] Figure 3E A schematic diagram of another type of scanning area division provided in an embodiment of the present application;

[0027] Figure 4 A schematic diagram of the structure of a detection threshold determination device provided in an embodiment of the present application;

[0028] Figure 5 A schematic diagram of the structure of a laser radar provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0030] In the description of the present application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0031] like Figure 1ASchematic diagram of echo signal detection waveform shown. The laser radar can use a laser emitting component to transmit a detection signal to the target scene, and use a receiving component to receive the echo signal reflected back from the target scene. Furthermore, the echo signal can be sampled using a detection threshold. When the rising edge of the echo signal crosses the detection threshold, a sampling time is recorded, and when the falling edge of the echo signal crosses the threshold, a sampling time is recorded. When an echo signal completes two time samplings, the reception time of the target echo signal can be obtained through a preset algorithm. Based on the reception time of the target signal, the relevant ranging information corresponding to the target echo signal can be determined. However, when the ambient temperature of the laser radar is high or the ambient light is strong, the amplitude of the noise signal received by the receiving component will increase significantly. For example, in scenes such as dawn or dusk, the incident angle of sunlight may be directly received by the galvanometer in an almost horizontal direction (i.e., a smaller incident angle). If the detection threshold of normal temperature and low ambient light illumination is still used, the number of noise echo signals detected between time T1 and T2 will increase sharply, and the noise signal may be mistaken for the target echo signal; but if a higher detection threshold is adapted, the target echo signal may not be detected at normal temperature and low ambient light illumination, resulting in a decrease in the ranging capability of the laser radar.

[0032] Therefore, the present application provides a detection threshold determination method to reduce the impact of ambient light on the ranging accuracy of lidar in different scenarios. The applicable lidars include but are not limited to: mechanical rotation type, hybrid solid-state type (for example, micro-electromechanical system MEMS, rotating mirror scanning type), and pure solid-state type (for example, optical phased array OPA, flash Flash).

[0033] like Figure 1B An application scenario diagram of the detection threshold determination method used in the present application is shown. The detection threshold used in the present application is illustrated by taking a MEMS laser radar as an example. Specifically, the laser radar includes a galvanometer (not shown in the figure) for scanning a target scene. The galvanometer usually has a rotation axis in two directions, namely a fast axis and a slow axis, and the fast axis and the slow axis are perpendicular to each other. After the galvanometer completes scanning the target scene, a two-dimensional scanning area can be obtained.

[0034] When the LiDAR is fixed facing forward, the fast axis is usually used for horizontal scanning, and the slow axis is usually used for vertical scanning. The two are combined to achieve two-dimensional scanning. The field of view (FOV) of the LiDAR indicates the size of the scanning area, which can be measured in terms of angles (horizontal FOV and vertical FOV) from the horizontal and vertical dimensions.

[0035] Next, combine Figure 1A The waveform diagram of the detection echo signal introduced and Figure 1BThe application scenario diagram of the detection threshold method adopted in the present application is introduced to introduce the detection threshold method provided in the embodiment of the present application.

[0036] In one embodiment, Figure 2 A flow chart of a detection threshold method is shown. The detection threshold method may include the following steps:

[0037] S201, obtaining the number of noise echoes in the blanking area of ​​the i-th scanning cycle.

[0038] It can be understood that when the laser radar using the detection threshold method in the embodiment of the present application is in the working area of ​​the scanning cycle, it is necessary to transmit multiple detection signals to the scanning area. That is to say, in each detection cycle within the N detection cycles included in the working area, at least one detection signal will be transmitted to the scanning area.

[0039] Each scanning cycle may include a working area and a blanking area. The working area represents a scanning time period of the scanning cycle, and the blanking area represents a retrace time period of the scanning cycle; i is a positive integer.

[0040] The working area in the embodiment of the present application represents the time from the start of scanning at the starting position to the completion of scanning in the i-th scanning cycle, and the blanking area represents the time from the scanning device returning to the starting position after the scanning of the i-th scanning cycle is completed.

[0041] For example, see Figure 1B , the working area refers to the process of the scanning angle of the galvanometer running from the upper left to the lower left of the field of view FOV, and the blanking area is the retracement time of the galvanometer, that is, the position recovery process of the scanning angle of the galvanometer running from the lower left to the upper left. During the blanking period, the laser radar does not emit laser light, that is, the detection signal. Of course, the scanning order of the galvanometer can be controlled by the fast axis drive signal and the slow axis drive signal. The scanning process can also be running from the upper right corner to the lower right corner and then retrace to the upper right corner starting position, or running from the lower left corner to the upper left corner and then retrace to the lower left corner, or running from the lower right corner to the upper right corner and then retrace to the lower right corner. The working area of ​​the scanning cycle refers to the process of the galvanometer deflecting the detection signal to scan the target scene, and the blanking area refers to the process of the detection signal returning to the scanning starting position after completing the scanning of the target scene. The following is an example of the process of the galvanometer scanning order running from the upper left corner to the lower left corner as the working area and the process of returning from the lower left corner to the upper left corner as the blanking area.

[0042] It can be understood that the embodiment of the present application can detect the number of noise echoes of the current frame in the blanking area, because the echo signal at this time is generated by the dark current of the photoelectric device, circuit ripple, ambient light, etc., that is, the noise signal. If the number of echoes obtained in the blanking area is more, it means that the noise is greater.

[0043] S202, determining a detection threshold of a working area in an (i+1)th scanning cycle according to the number of noise echoes and a detection threshold of a working area in an i-th scanning cycle.

[0044] In this way, after determining the number of noise echoes in the blanking area of ​​the i-th scanning cycle, the embodiment of the present application can comprehensively measure the detection threshold of the working area of ​​the i-th scanning cycle and the number of noise echoes in the blanking area to determine the detection threshold of the working area of ​​the i+1-th scanning cycle, so as to adaptively adjust the detection threshold of the next scanning cycle.

[0045] Therefore, the embodiment of the present application can determine the detection threshold of the working area of ​​the next scanning cycle by the number of noise echoes in the blanking area of ​​the i-th scanning cycle and the detection threshold of the working area of ​​the i-th scanning cycle, thereby realizing adaptive real-time adjustment of the detection threshold according to the current noise state, thereby achieving the purpose of improving the accuracy of relevant information of each object in the target scene measured by the laser radar.

[0046] In some embodiments, Figure 3A The flowchart of a detection threshold method provided by an embodiment of the present application is exemplarily shown. The detection threshold method may at least include the following steps:

[0047] S301, N detection cycles in the working area are divided into M first subsets according to a first preset rule, and the blanking area is divided into M second subsets according to a preset rule.

[0048] Wherein, N and M are both positive integers. Each first subset may include at least one detection cycle, each second subset may include at least one blanking period, and the division rules of the working area and the blanking area are the same.

[0049] It is understandable that, since the duration of the working area of ​​a scanning cycle is significantly longer than the duration of the blanking area, the duration of the detection cycle will be much longer than the duration of the blanking period, so the detection cycle is not equal to the blanking period. It is understandable that, in the embodiment of the present application, the scanning angle of the detection cycle included in the mth first subset is within the corresponding preset angle range, and the preset angle range may include a first direction preset angle range (e.g., horizontal FOV) and a second direction preset angle range (e.g., vertical FOV). Wherein, 1≤m≤M and m is an integer.

[0050] Specifically, in the embodiment of the present application, the scanning angle of the blanking time period included in the mth second subset is within the corresponding preset angle range; the preset angle range corresponding to the mth first subset is the same as the preset angle range corresponding to the mth second subset.

[0051] As can be seen from the above, the laser radar does not emit laser in the blanking area, but the galvanometer is still doing deflection motion. The galvanometer can receive ambient light in the field of view corresponding to the scanning angle. When the galvanometer moves in the blanking area, its scanning angle is aimed at a certain area in the field of view. The ambient light in this area can enter the receiving optical path inside the laser radar through the galvanometer, and is received by the laser radar receiver through the receiving optical path to output the echo signal. The fast axis of the galvanometer in the blanking area still maintains resonant motion, and the horizontal scanning angle covers the horizontal field of view angle; the slow axis of the galvanometer in the blanking area quickly retraces from bottom to top, and the vertical scanning angle covers the vertical field of view angle. Therefore, the scanning angle of the galvanometer in the blanking area can also cover the entire field of view. The scanning angle of the blanking time period contained in the second subset refers to the set of field of view areas that the galvanometer movement is aimed at during the blanking time period contained in the second subset.

[0052] Possibly, in the embodiment of the present application, the interval lengths of the M preset horizontal angle ranges are equal, and the interval lengths of the M preset vertical angle ranges are equal.

[0053] See also Figure 3B Schematic diagram of dividing the scanning area. In the embodiment of the present application, the lengths of the intervals corresponding to the scanning angles of the detection period contained in each first subset are all equal, that is, the entire scanning area is equally divided according to the scanning angles of the detection period, and P×Q first subsets are obtained, F p,q is the first subset of the p-th column and q-th row, where p and q are integers and 1≤p≤P, 1≤q≤Q. Figure 3C The figure shows the scanning angle of the slow axis. Figure 3C It can be observed that a scanning cycle can include the working area and the blanking area. The movement of the slow axis is a linear response to the driving signal, so the movement of the galvanometer around the slow axis is also uniform, from the vertical minimum angle to the vertical maximum angle. The vertical angle range is [miny p,1 ,maxy p,q ], maxy p,q-1 =miny p,q . Figure 3D The figure shows the scanning angle of the fast axis. Figure 3D It can be observed that the motion of the fast axis is resonant motion, so whether it is in the working area or the blanking area, it always maintains resonant motion and reciprocates between the maximum horizontal angle and the minimum horizontal angle. The horizontal angle range is [minp 1,q ,maxp p,q ],minp p,q =maxp p-1,q Finally, the superposition of the motions in the fast axis and the slow axis results in the scanning motion of the galvanometer.

[0054] In a specific example, the horizontal FOV of the entire scanning area is -50°~50°, and the vertical FOV is -20°~20°. In the working area, the galvanometer scans line by line. In one fast-axis scanning cycle, the horizontal scanning angle of the galvanometer deflected around the fast axis first moves from the leftmost side of the scanning area to the rightmost side, and then returns from the rightmost side to the leftmost side; the distance between two scanning points with the same horizontal angle on adjacent rows is exactly the vertical scanning angle of the galvanometer deflected downward around the slow axis in one fast-axis scanning cycle. For example, Figure 3B There are 50 scanning points in each row of F. The scanning points are numbered in the scanning order. The first row is 1, 2, 3, 4, ..., 49, 50 from left to right. The second row is 51, 52, 53, ..., 100 from right to left. The third row is 101, 102, 103, ..., 150 from left to right, and so on. 1,1 The corresponding galvanometer scanning angle range covers three scanning points in the horizontal direction and three scanning points in the vertical direction, so it is divided into F 1,1 The scanning points in the first subset are 1, 2, 3, 98, 99, 100, 101, 102, and 103, respectively, and the detection periods corresponding to these scanning points are the detection periods included in the first subset 1. Possibly, the interval lengths of the M preset horizontal angle ranges in the embodiment of the present application are not equal, and the interval lengths of the M preset vertical angle ranges are not equal.

[0055] It is understandable that since the lidar pays more attention to the relevant information of objects in the area directly in front of the target scene, the detection accuracy of the central area is often higher than that of the surrounding areas.

[0056] In some possible embodiments, Figure 3E As shown, the angle range corresponding to the center area of ​​the entire scanning area (for example, F p,q ) is set to be smaller than the angle range corresponding to the surrounding area (for example, F 1,1 、F P,1 、F 1,Q 、F P,Q ,). The number of detection cycles contained in the first subset corresponding to the angle range corresponding to the central area is smaller, and the number of blanking time periods contained in the corresponding second subset is smaller, so that the detection cycle of the central area of ​​the entire scanning area of ​​the laser radar can be divided more finely, that is, the first subset with uneven division granularity is obtained, so that the detection threshold can be finely set for the first subset of the central area, thereby improving the detection accuracy of the central area.

[0057] It can be known that in order to improve the detection accuracy of the central area, the scanning speed of the galvanometer in the central area of ​​the working area can be lower than the scanning speed of the galvanometer in the edge area, especially the scanning speed in the slow axis direction. That is to say, during the operation of the galvanometer, the angle range of the edge area (for example Figure 3B F 1,1 、F 2,1 、F P,1 、F 1,Q 、F P,Q The scanning speed during scanning is greater than the angular range in the central area (e.g. Figure 3B F p,q ) Scanning speed during scanning. It can be seen that since the movement of the fast axis of the galvanometer is a resonant motion, it is difficult to accurately control the instantaneous speed of the galvanometer movement, but the movement of the slow axis responds linearly to the drive signal and the scanning speed can be adjusted. Therefore, by controlling the scanning speed of the slow axis, it is possible to achieve dense scanning of the central area and improve the resolution of the central area. At this time, if the following is adopted Figure 3B The uniform division method shown in the figure shows that the central area (such as F p,q ) contains more scanning points within the angle range, and the corresponding central area angle range corresponds to more detection cycles, which makes it impossible to finely control the detection threshold of the detection cycle of the central area, affecting the detection accuracy of the central area. However, by dividing the angle range of the central area into a smaller angle range and a larger angle range of the edge area, the scanning angle is divided according to the distribution of the laser radar's scanning points, which can more accurately control the detection threshold of each detection area and improve the overall detection accuracy of the laser radar.

[0058] S302 , adjusting the detection threshold of the mth first subset in the ith scanning cycle based on a preset adjustment value to obtain the noise detection threshold of the mth second subset in the ith scanning cycle.

[0059] It can be understood that each first subset in the embodiment of the present application is configured with a detection threshold A m The detection threshold of the mth first subset refers to the detection threshold of any first subset among the M first subsets.

[0060] It is understandable that the first subset F p,qThe detection threshold refers to the detection threshold of each detection cycle in the first subset when it is in the working state, and the detection threshold of all detection cycles contained in the same first subset is the same. As can be seen from the above, although the laser radar does not emit a detection signal in the blanking zone of the scanning cycle, it can still receive ambient light through the galvanometer and is received by the light receiving component; during this period of time, the fast-axis drive signal remains unchanged, the galvanometer maintains resonant motion in the horizontal direction, and the slow-axis drive signal drives the galvanometer to return from the bottom to the top in the vertical direction. In the blanking zone, the scanning angle of the galvanometer can also cover the entire field of view. In this way, the embodiment of the present application corresponds the mth first subset to the mth second subset so that their corresponding preset scanning angles are the same.

[0061] Specifically, the embodiment of the present application can determine the detection threshold of the mth first subset of the first scanning cycle of the laser radar as the initial value. In other words, the detection threshold corresponding to the initial state of the M first subsets of the first scanning cycle of the laser radar is determined.

[0062] Possibly, in the embodiment of the present application, the initial values ​​of the detection thresholds of each first subset in the first scanning cycle are all equal. Specifically, the initial values ​​can be pre-stored in the laser radar system, so that the laser radar can obtain the initial values ​​when it is powered on, as the detection thresholds of all detection cycles in the first scanning cycle.

[0063] Possibly, in the embodiment of the present application, the detection threshold of each first subset after the laser radar last worked can also be determined as the detection threshold of the first subset corresponding to the first scanning cycle.

[0064] Possibly, the initial values ​​obtained for the detection thresholds of the M first subsets of the first scanning cycle in the embodiment of the present application may be different. Since the scanning order of the galvanometer within the scanning cycle is known, the initial value of the detection threshold of the detection cycle contained in each first subset can be determined according to the position of the angle range corresponding to each first subset in the scanning area of ​​the laser radar. Exemplarily, the scanning points within the angle range of the upper area and the middle area of ​​the scanning area are usually directed far forward and upward, and the light receiving component accumulates more noise. The initial values ​​of the detection cycles corresponding to these angle ranges can be set slightly higher; the scanning points within the angle range of the lower area of ​​the scanning area are usually directed to the ground, the detection distance is shorter, and the light receiving component accumulates less noise. The initial values ​​of the detection cycles corresponding to these angle ranges can be set slightly lower.

[0065] The noise detection threshold is the detection threshold of the second subset, and the detection threshold of the mth second subset refers to the detection threshold of any second subset in the M second subsets. As mentioned above, the laser radar can still receive the ambient light in the scanning area in the blanking area, and the light receiving component responds to output the echo signal. The noise detection threshold is used to sample the received echo signal in the blanking area to detect the intensity of the ambient light and then determine the noise intensity.

[0066] Specifically, the calculation method of adjusting the detection threshold of the mth first subset of the i-th scanning period based on the preset adjustment value in the embodiment of the present application is:

[0067] A' m (i) = A m (i) ±ΔA;

[0068] Among them, A' m (i) is the noise detection threshold of the mth second subset in the i-th scanning cycle, A m (i) is the detection threshold of the mth first subset in the i-th scanning cycle, and ΔA is the preset adjustment value.

[0069] It can be understood that according to the above formula, the detection threshold A of the mth first subset in the i-th scanning cycle is m (i) minus the preset adjustment value ΔA to reduce the detection threshold in the blanking area, thereby obtaining the noise detection threshold A' of the mth second subset in the i-th scanning cycle. m (i). In this way, the echo signal in the blanking area can be sampled by using the noise detection threshold, and the number of noise echo signals in the mth second subset of the i-th scanning cycle can be counted. In some possible application scenarios, the detection threshold A of the mth first subset of the i-th scanning cycle can also be used. m Based on (i), a preset adjustment value ΔA is added to increase the detection threshold in the blanking area, which is not limited in the embodiment of the present application.

[0070] Possibly, the preset adjustment value in the embodiment of the present application is several photon amplitudes, such as 1 photon amplitude, 2 photon amplitudes, 3 photon amplitudes, etc. Specifically, a photon amplitude represents the pulse amplitude that can be generated after the receiving component receives a photon. The photon amplitudes corresponding to receiving components of different types or brands may be different.

[0071] S303: Using a noise detection threshold, determine the number of noise echoes in the mth second subset in the ith scanning cycle.

[0072] When the scanning angle of the galvanometer enters the angle range corresponding to the mth second subset of the blanking area, A′ can be used m(i) Sampling the echo signal to obtain the number of noise echoes. In the embodiment of the present application, the echo signal obtained from the mth second subset in the i-th scanning cycle may be sampled based on the noise detection threshold to determine the number of noise echoes in the mth second subset.

[0073] For details, see Figure 3B , for F in the i-th scanning cycle P,Q The detection threshold of the detection cycle contained in the corresponding first subset is adjusted to obtain F in the same scanning cycle P,Q The corresponding second subset includes the noise detection threshold of the blanking time period, and the adjusted noise detection threshold is used to adjust F P,Q The echo signal received during the blanking period included in the corresponding second subset is sampled to obtain F P,Q The amount of noise echo caused by ambient light within the angular range.

[0074] It can be understood that, the more echo signals caused by noise received by the receiving component and the greater their energy, the more echo signals can be sampled by the noise detection threshold.

[0075] S304 , determining a detection threshold of the mth first subset in the (i+1)th scanning cycle according to the number of noise echoes and the detection threshold of the mth first subset in the ith scanning cycle.

[0076] Specifically, the detection threshold of the mth first subset in the (i+1)th scanning cycle satisfies the following calculation method:

[0077] A m (i+1)=A m (i)±k×N p ;

[0078] Among them, A m (i+1) is the detection threshold of the mth first subset in the i+1th scanning cycle, A m (i) is the detection threshold of the mth first subset in the i-th scanning cycle, N p is the number of noise echoes in the mth second subset in the ith scanning cycle, and k is the adjustment coefficient.

[0079] In a specific example, in the presence of echo signals with a lot of noise, the detection threshold determination method of the embodiment of the present application can be used to adjust the detection threshold of each scanning cycle working area. According to the number of noise echoes obtained by statistics, the detection threshold of the first subset corresponding to the next scanning cycle is adjusted to reduce the impact of excessive noise on the accuracy of laser radar detection.

[0080] The more noise echoes there are, the more noise echo signals caused by ambient light and the higher the amplitude. If the original detection threshold is still used to sample the echo signal, it is very likely that the sampling result obtained is the sampling result of the noise signal, and it is impossible to distinguish between the noise signal and the detection signal. It is easy to lose the sampling result of the detection signal, resulting in inaccurate detection of the laser radar. At this time, it is necessary to increase the detection threshold of the detection cycle contained in the same first subset of the next scanning cycle based on the detection threshold of the first subset corresponding to the previous scanning cycle.

[0081] On the contrary, the fewer the number of noise echoes, the fewer noise echo signals caused by ambient light and the lower the amplitude. If the original detection threshold is still used to sample the echo signal, it is very likely that the detection echo between the detection threshold and the background noise will not be sampled, resulting in the loss of small detection echoes, such as the echo signals of distant target objects and the echo signals of low reflectivity target objects. Such target objects cannot be effectively detected. At this time, it is necessary to lower the detection threshold of the detection cycle contained in the same first subset of the next scanning cycle based on the detection threshold of the first subset corresponding to the previous scanning cycle.

[0082] The detection threshold determination method of the embodiment of the present application uses the blanking zone to count the number of noise echoes caused by ambient light, and adjusts the detection threshold of the next scanning cycle according to the number of noise echoes. At the same time, in order to finely control the detection threshold of N detection cycles in the scanning cycle, the N detection cycles are divided into M groups according to the position of the scanning angle in the field of view of the laser radar, each group is a first subset, and all detection cycles contained in a first subset are taken as a whole, and the same detection threshold is set. Correspondingly, the retracement area is also divided into M groups according to the position of the scanning angle in the field of view of the laser radar during the retracement of the galvanometer, and each group is a second subset. The M first subsets correspond to the M second subsets one by one, and the corresponding detection cycle contained in the first subset and the blanking time period contained in the second subset have the same scanning angle, that is, the corresponding first subset and the second subset both receive the echo signal of the same area in the field of view of the laser radar. In this way, the detection thresholds of multiple detection cycles in the scanning cycle are accurately controlled, and the laser radar can detect more accurately.

[0083] Specifically, when the laser radar is powered on, the initial value of the detection threshold of each first subset of the working area of ​​the first scanning cycle can be obtained from the system. In order to obtain as many noise echo signals as possible in the blanking area of ​​the first scanning cycle, the noise detection threshold of the mth first subset of the working area of ​​the first scanning cycle can be subtracted by 1 photon amplitude to determine the noise detection threshold of the mth second subset of the blanking area of ​​the first scanning cycle, and the noise detection threshold of the second subset is used to sample the echo signals received by the second subset to determine the number of noise echo signals. After obtaining the number of noise echo signals in the blanking area of ​​the first scanning cycle, the detection threshold of the first subset of the working area of ​​the second scanning cycle can be increased based on the number of noise echo signals in the first scanning cycle and the detection threshold of the first subset in the working area of ​​the first scanning cycle, so as to filter out as many noise echo signals as possible in the second scanning cycle; the subsequent scanning cycles are analogous to each other, thereby improving the ranging accuracy of the laser radar.

[0084] The detection threshold determination method of the embodiment of the present application can count the number of noise echoes in the blanking area of ​​each scanning cycle and adjust the detection threshold of the working area of ​​the next scanning cycle. The detection threshold determination method of the embodiment of the present application can also be performed once every preset time interval; for example, the detection threshold is adjusted once every 10 scanning cycles; the blanking area of ​​the 10th scanning cycle starts to count the number of noise echoes, and the detection threshold of the working area of ​​the 11th scanning cycle is adjusted, and the working areas of the 11th to 20th scanning cycles all maintain the detection threshold determined by the 11th scanning cycle; and so on, the blanking area of ​​the 20th scanning cycle starts to count the number of noise echoes.

[0085] Therefore, the embodiment of the present application can adjust the detection threshold of the detection cycle corresponding to each part in the scanning area by dividing the scanning area into subsets, so as to make the adjustment more precise. In addition, the embodiment of the present application also takes into account the possible influence of the ambient light scene on the detection threshold during the adjustment process, and slightly reduces the detection threshold of each first subset by means of a preset adjustment value, so as to more accurately obtain the number of noise echoes in the blanking area, and then determine the detection threshold of the same first subset in the working area of ​​the next scanning cycle based on the number of noise echoes, thereby realizing adaptive real-time adjustment of the detection threshold of each first subset, thereby effectively improving the accuracy of the relevant information of each object in the target scene detected by the laser radar.

[0086] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0087] Figure 4 1 is a schematic diagram of the structure of a detection threshold determination device provided by an exemplary embodiment of the present application. The device executes the detection threshold determination method of any of the above embodiments of the present application. Figure 4 As shown, the detection threshold determination method may include:

[0088] An acquisition module, used for acquiring the number of noise echoes in the blanking area of ​​the i-th scanning cycle;

[0089] A determination module, used to determine the detection threshold of the working area of ​​the (i+1)th scanning cycle according to the number of noise echoes and the detection threshold of the working area of ​​the i-th scanning cycle;

[0090] Each scanning cycle includes a working area and a blanking area; the working area represents the scanning time period of the scanning cycle, and the blanking area represents the retrace time period of the scanning cycle; i is a positive integer.

[0091] Therefore, in the embodiment of the present application, the detection threshold of the working area of ​​the next scanning cycle can be determined by detecting the number of noise echoes in the blanking area of ​​the ith scanning cycle and the detection threshold of the working area of ​​the ith scanning cycle, thereby realizing adaptive real-time adjustment of the detection threshold according to the current noise state, thereby achieving the purpose of improving the accuracy of relevant information of each object in the target scene measured by the laser radar.

[0092] In some embodiments, the working area includes N detection cycles, the N detection cycles are divided into M first subsets according to a first preset rule, and each of the first subsets includes at least one detection cycle; the blanking area is divided into M second subsets according to the first preset rule, and each of the second subsets includes at least one blanking time period; wherein N and M are both positive integers;

[0093] The determination module is specifically used for:

[0094] Based on the number of noise echoes in the mth second subset in the i-th scanning cycle and the detection threshold of the mth first subset in the i-th scanning cycle, the detection threshold of the mth first subset in the i+1-th scanning cycle is determined; wherein 1≤m≤M and m is an integer.

[0095] In some implementations, the N detection cycles are divided into M first subsets according to a first preset rule, including:

[0096] The scanning angle of the detection cycle included in the mth first subset is within the corresponding preset angle range;

[0097] The blanking area is divided into M second subsets according to the first preset rule, including: the scanning angle of the blanking time period included in the m-th second subset is within the corresponding preset angle range; the preset angle range corresponding to the m-th first subset is the same as the preset angle range corresponding to the m-th second subset;

[0098] The preset angle range includes a first direction preset angle range and a second direction preset angle range.

[0099] In some implementations, the lengths of the intervals of the M preset angle ranges in the first direction are equal, and the lengths of the intervals of the M preset angle ranges in the second direction are equal.

[0100] In some embodiments, the device further comprises:

[0101] An initial value determination module is used to determine the detection threshold of the mth first subset of the first scanning cycle as an initial value; or to determine the detection threshold of the mth first subset of the first scanning cycle based on the scanning angle of the detection cycle contained in the mth first subset of the first scanning cycle.

[0102] In some embodiments, the acquisition module includes:

[0103] An obtaining module, configured to adjust the detection threshold of the mth first subset of the i-th scanning cycle based on a preset adjustment value to obtain the noise detection threshold of the mth second subset of the i-th scanning cycle;

[0104] The noise echo quantity determination module is used to determine the noise echo quantity of the mth second subset in the ith scanning cycle by using the noise detection threshold.

[0105] In some implementations, the noise detection threshold of the mth second subset in the ith scanning cycle satisfies the following calculation method:

[0106] A' m (i) = A m (i) ±ΔA;

[0107] Among them, A' m (i) is the noise detection threshold of the mth second subset for the i-th scanning cycle, A m(i) is the detection threshold of the mth first subset in the i-th scanning cycle, and ΔA is the preset adjustment value.

[0108] In some implementations, the detection threshold of the mth first subset in the (i+1)th scanning period satisfies the following calculation method:

[0109] A m (i+1)=A m (i)±k×N p ;

[0110] Among them, A m (i+1) is the detection threshold of the mth first subset in the i+1th scanning cycle, A m (i) is the detection threshold of the mth first subset in the i-th scanning cycle, N p is the number of noise echoes in the mth second subset in the ith scanning cycle, and k is the adjustment coefficient.

[0111] It should be noted that the detection threshold determination device provided in the above embodiment only uses the division of the above functional modules as an example when performing radar performance detection. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the detection threshold determination device provided in the above embodiment and the detection threshold determination method embodiment belong to the same concept, and the implementation process thereof is detailed in the method embodiment, which will not be repeated here.

[0112] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0113] See also Figure 5 , which is a schematic diagram of the structure of a terminal provided in an embodiment of the present application. Figure 5 As shown, the terminal 50 may include: at least one processor 51 , at least one network interface 54 , a user interface 53 , a memory 55 , and at least one communication bus 52 .

[0114] The communication bus 52 is used to realize the connection and communication between these components.

[0115] The user interface 53 may include a display screen (Display) and a camera (Camera), and the optional user interface 53 may also include a standard wired interface and a wireless interface.

[0116] The network interface 54 may optionally include a standard wired interface or a wireless interface (such as a WI-FI interface).

[0117] Among them, the processor 51 may include one or more processing cores. The processor 51 uses various interfaces and lines to connect various parts in the entire terminal 50, and executes various functions and processes data of the terminal 50 by running or executing instructions, programs, code sets or instruction sets stored in the memory 55, and calling data stored in the memory 55. Optionally, the processor 51 can be implemented in at least one hardware form of digital signal processing (Digital Signal Processing, DSP), field programmable gate array (Field-Programmable Gate Array, FPGA), and programmable logic array (Programmable Logic Array, PLA). The processor 51 can integrate one or a combination of a central processing unit (Central Processing Unit, CPU), a graphics processing unit (Graphics Processing Unit, GPU) and a modem. Among them, the CPU mainly processes the operating system, user interface and application programs; the GPU is responsible for rendering and drawing the content to be displayed on the display screen; and the modem is used to process wireless communications. It can be understood that the above-mentioned modem may not be integrated into the processor 51, but may be implemented separately through a chip.

[0118] The memory 55 may include a random access memory (RAM) or a read-only memory (Read-Only Memory). Optionally, the memory 55 includes a non-transitory computer-readable storage medium. The memory 55 may be used to store instructions, programs, codes, code sets or instruction sets. The memory 55 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the above-mentioned method embodiments, etc.; the data storage area may store data involved in the above-mentioned method embodiments, etc. The memory 55 may optionally be at least one storage device located away from the aforementioned processor 51. As Figure 5 As shown, the memory 55 as a computer storage medium may include an operating system, a network communication module, a user interface module, and a mixing application.

[0119] exist Figure 5In the terminal 50 shown, the user interface 53 is mainly used to provide an input interface for the user and obtain the data input by the user; and the processor 51 can be used to call the mixing application stored in the memory 55 and specifically perform the following operations:

[0120] Obtain the number of noise echoes in the blanking area of ​​the i-th scanning cycle;

[0121] Determine the detection threshold of the working area of ​​the (i+1)th scanning cycle according to the number of noise echoes and the detection threshold of the working area of ​​the i-th scanning cycle;

[0122] Each scanning cycle includes a working area and a blanking area; the working area represents the scanning time period of the scanning cycle, and the blanking area represents the retrace time period of the scanning cycle; i is a positive integer.

[0123] In a possible embodiment, the working area includes N detection cycles, the N detection cycles are divided into M first subsets according to a first preset rule, and each of the first subsets includes at least one detection cycle; the blanking area is divided into M second subsets according to the first preset rule, and each of the second subsets includes at least one blanking time period; wherein N and M are both positive integers;

[0124] When the processor 51 executes the step of transmitting a plurality of detection signals to the scanning area, determining the detection threshold of the working area of ​​the i+1th scanning cycle based on the number of noise echoes in the blanking area of ​​the i-th scanning cycle and the detection threshold of the working area of ​​the i-th scanning cycle, the processor 51 specifically executes:

[0125] Based on the number of noise echoes in the mth second subset in the i-th scanning cycle and the detection threshold of the mth first subset in the i-th scanning cycle, the detection threshold of the mth first subset in the i+1-th scanning cycle is determined; wherein 1≤m≤M and m is an integer.

[0126] In a possible embodiment, the processor 51 executes

[0127] When the N detection cycles are divided into M first subsets according to the first preset rule, specifically performing:

[0128] The scanning angle of the detection cycle included in the mth first subset is within the corresponding preset angle range;

[0129] The blanking area is divided into M second subsets according to the first preset rule, including: the scanning angle of the blanking time period included in the m-th second subset is within the corresponding preset angle range; the preset angle range corresponding to the m-th first subset is the same as the preset angle range corresponding to the m-th second subset;

[0130] The preset angle range includes a first direction preset angle range and a second direction preset angle range.

[0131] In a possible embodiment, the interval lengths of the M preset angle ranges in the first direction are equal, and the interval lengths of the M preset angle ranges in the second direction are equal.

[0132] In a possible embodiment, the processor 51 further executes:

[0133] Determine the detection threshold of the mth first subset in the first scanning cycle as the initial value; or

[0134] The detection threshold of the mth first subset of the first scanning cycle is determined according to the scanning angle of the detection cycle included in the mth first subset of the first scanning cycle.

[0135] In a possible embodiment, when the processor 51 acquires the number of noise echoes in the blanking area of ​​the i-th scanning cycle, the processor 51 specifically performs:

[0136] Adjusting the detection threshold of the mth first subset of the i-th scanning cycle based on a preset adjustment value to obtain the noise detection threshold of the mth second subset of the i-th scanning cycle;

[0137] The noise detection threshold is used to determine the number of noise echoes in the mth second subset of the i-th scanning cycle.

[0138] In a possible embodiment, the noise detection threshold of the mth second subset in the ith scanning cycle satisfies the following calculation method:

[0139] A' m (i) = A m (i) ±ΔA;

[0140] Among them, A' m (i) is the noise detection threshold of the mth second subset for the i-th scanning cycle, A m (i) is the detection threshold of the mth first subset in the i-th scanning cycle, and ΔA is the preset adjustment value.

[0141] In a possible embodiment, the detection threshold of the mth first subset in the (i+1)th scanning period satisfies the following calculation method:

[0142] A m (i+1)=A m (i)±k×N p ;

[0143] Among them, A m(i+1) is the detection threshold of the mth first subset in the i+1th scanning cycle, A m (i) is the detection threshold of the mth first subset in the i-th scanning cycle, N p is the number of noise echoes in the mth second subset in the ith scanning cycle, and k is the adjustment coefficient.

[0144] The embodiment of the present application also provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed on a computer or a processor, the computer or the processor executes the above-mentioned Figure 2 and Figure 3A One or more steps in the illustrated embodiment. If the components of the radar performance detection device described above are implemented in the form of software functional units and sold or used as independent products, they can be stored in the computer-readable storage medium.

[0145] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted by the computer-readable storage medium. The computer instructions can be transmitted from a website site, a computer, a server or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server, a data center, etc. that contains one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital versatile disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0146] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The aforementioned storage medium includes: various media that can store program codes, such as system memory (Read Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk. In the absence of conflict, the technical features in this embodiment and the implementation scheme can be combined arbitrarily.

[0147] The embodiments described above are merely preferred embodiments of the present application and are not intended to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements made to the technical solutions of the present application by ordinary technicians in this field should fall within the protection scope determined by the claims of the present application.

Claims

1. A method for determining a detection threshold, characterized in that: The method comprises: Obtain the number of noise echoes in the blanking area of ​​the i-th scanning cycle; Determine the detection threshold of the working area of ​​the (i+1)th scanning cycle according to the number of noise echoes and the detection threshold of the working area of ​​the i-th scanning cycle; The scanning cycle includes a working area and a blanking area; the working area represents the scanning time period of the scanning cycle, and the blanking area represents the retrace time period of the scanning cycle; i is a positive integer.

2. The method according to claim 1, characterized in that The working area includes N detection cycles, the N detection cycles are divided into M first subsets according to a first preset rule, and each of the first subsets includes at least one detection cycle; the blanking area is divided into M second subsets according to the first preset rule, and each of the second subsets includes at least one blanking time period; wherein N and M are both positive integers; The method of determining the detection threshold of the working area of ​​the (i+1)th scanning cycle based on the number of noise echoes in the blanking area of ​​the i-th scanning cycle and the detection threshold of the working area of ​​the i-th scanning cycle comprises: Based on the number of noise echoes in the mth second subset in the i-th scanning cycle and the detection threshold of the mth first subset in the i-th scanning cycle, the detection threshold of the mth first subset in the i+1-th scanning cycle is determined; wherein 1≤m≤M and m is an integer.

3. The method according to claim 2, characterized in that The N detection cycles are divided into M first subsets according to a first preset rule, including: the scanning angle of the detection cycle included in the mth first subset is within the corresponding preset angle range; The blanking area is divided into M second subsets according to the first preset rule, including: the scanning angle of the blanking time period included in the m-th second subset is within the corresponding preset angle range; the preset angle range corresponding to the m-th first subset is the same as the preset angle range corresponding to the m-th second subset; The preset angle range includes a first direction preset angle range and a second direction preset angle range.

4. The method according to claim 3, characterized in that The lengths of the intervals of the M preset angle ranges in the first direction are equal, and the lengths of the intervals of the M preset angle ranges in the second direction are equal.

5. The method according to claim 3, characterized in that: The method further comprises: An initial value of a detection threshold of the mth first subset of the first scanning cycle is determined according to the scanning angle of the detection cycle included in the mth first subset of the first scanning cycle.

6. The method according to claim 2, characterized in that The obtaining the number of noise echoes in the blanking area of ​​the i-th scanning cycle includes: Adjusting the detection threshold of the mth first subset of the i-th scanning cycle based on a preset adjustment value to obtain the noise detection threshold of the mth second subset of the i-th scanning cycle; The noise detection threshold is used to determine the number of noise echoes in the mth second subset of the i-th scanning cycle.

7. The method according to claim 6, characterized in that The noise detection threshold of the mth second subset of the i-th scanning cycle satisfies the following calculation method: A’ m (i)=A m (i)±ΔA; Among them, A' m (i) is the noise detection threshold of the mth second subset in the i-th scanning cycle, A m (i) is the detection threshold of the mth first subset in the i-th scanning cycle, and ΔA is the preset adjustment value.

8. The method according to claim 2, characterized in that: The detection threshold of the mth first subset in the i+1th scanning cycle satisfies the following calculation method: A m (i+1)=A m (i)±k×N p ; Among them, A m (i+1) is the detection threshold of the mth first subset in the i+1th scanning cycle, A m (i) is the detection threshold of the mth first subset in the i-th scanning cycle, N p is the number of noise echoes in the mth second subset in the ith scanning cycle, and k is the adjustment coefficient.

9. A detection threshold determination device, characterized in that: The device comprises: An acquisition module, used for acquiring the number of noise echoes in the blanking area of ​​the i-th scanning cycle; A determination module, used to determine the detection threshold of the working area of ​​the (i+1)th scanning cycle according to the number of noise echoes and the detection threshold of the working area of ​​the i-th scanning cycle; Each scanning cycle includes a working area and a blanking area; the working area represents the scanning time period of the scanning cycle, and the blanking area represents the retrace time period of the scanning cycle; i is a positive integer.

10. A computer storage medium, characterized in that: The computer storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor and executing the method steps according to any one of claims 1-8.

11. A laser radar, characterized in that: include: A processor and a memory; wherein the memory stores a computer program, and the computer program is suitable for being loaded by the processor and executing the method steps as claimed in any one of claims 1 to 8.

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