A stray light filtering method, device and laser radar

Abstract

The embodiments of the present invention relate to the technical field of laser radar data processing, and disclose a stray light filtering method, device and laser radar. The method first needs to obtain the light spot data received by the laser radar in the current environment, and extract the light spot from the light spot data, and then judge whether the current environment is a strong light environment based on the light spot and the light spot data. When it is a strong light environment, it is determined whether the light spot is an abnormal light spot by judging whether the energy distribution and / or waveform of the light spot is abnormal. When it is determined to be an abnormal light spot, the abnormal light spot is filtered out as an invalid light spot, thereby filtering out the stray light. This stray light filtering method has a small amount of calculation and can achieve a better filtering effect.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of laser radar data processing technology, and in particular to a stray light filtering method, device and laser radar. Background Art

[0002] Laser Radar is a radar system that emits laser beams to detect the position, speed and other characteristic quantities of a target. Its working principle is to emit a detection laser to the target, and then compare the laser reflected from the target with the emitted laser signal. After appropriate processing, the relevant information of the target can be obtained.

[0003] Distance measurement is currently a very common application scenario of LiDAR. One of the working principles of LiDAR ranging is that the LiDAR outputs a laser beam. The laser spot formed by the laser beam hitting the surface of the object is reflected onto the area array camera. After image processing, the centroid of the spot is extracted and the distance to the object can be calculated.

[0004] In the process of implementing the embodiments of the present invention, the inventors found that there are at least the following problems in the above-mentioned related technologies: in actual working scenarios, when strong light also shines on the sensor surface of the lidar, it is easy to cause interference to the laser spot, which manifests as the point cloud appearing as ray-shaped or scattered noise, resulting in errors in centroid extraction and causing misjudgment of the scene. Summary of the invention

[0005] The embodiments of the present application provide a stray light filtering method, device and laser radar.

[0006] The purpose of the embodiment of the present invention is achieved through the following technical solutions:

[0007] To solve the above technical problems, in the first aspect, a stray light filtering method is provided in an embodiment of the present invention, which is applied to a laser radar. The method includes: obtaining light spot data received by the laser radar in the current environment, and extracting light spots from the light spot data; judging whether the current environment is a strong light environment according to the light spot and the light spot data; if it is judged to be a strong light environment, judging whether the light spot is an abnormal light spot with abnormal energy distribution and / or abnormal waveform; if it is judged to be an abnormal light spot, filtering the abnormal light spot as an invalid light spot.

[0008] In some embodiments, the light spot data at least includes: judging whether the current environment is a strong light environment based on the light spot and the light spot data, including: calculating the background brightness of the light spot and the ratio of the light spot peak to the background brightness based on the light spot data; judging whether the ratio of the light spot peak to the background brightness is lower than a preset ratio threshold, and / or whether the background brightness is higher than a preset brightness threshold; if so, determining that the current environment is a strong light environment.

[0009] In some embodiments, the method further includes: constructing scenes with two different illuminations, normal light and strong light, and collecting experimental data; and according to the experimental data, setting the preset ratio threshold and / or the preset brightness threshold for determining whether it is a strong light environment.

[0010] In some embodiments, extracting the light spot from the light spot data includes: drawing a light spot waveform diagram according to the light spot data, and determining multiple candidate light spots from the light spot waveform diagram; determining the spot centroid and spot width of each candidate light spot; according to the light spot centroid, determining the upper limit and lower limit of the spot width corresponding to the centroid position of each candidate light spot; taking the spot with the largest peak value among the candidate light spots whose spot width is within the range defined by the upper limit and lower limit of the spot width as the spot to be extracted; and extracting the light spot to be extracted.

[0011] In some embodiments, the determining whether the light spot is an abnormal light spot with abnormal energy distribution and / or abnormal waveform includes: calculating the average grayscale value variation of the background brightness of the light spot within a preset range around the light spot; determining whether the average grayscale value variation is higher than a preset average grayscale value variation threshold; if so, determining that the light spot is an abnormal light spot.

[0012] In some embodiments, the determining whether the light spot is an abnormal light spot with abnormal energy distribution and / or abnormal waveform also includes: determining a brightness standard value based on the peak value of the light spot; obtaining the distance from the center of the light spot to the nearest wave crest boundary; and determining whether the light spot is an abnormal light spot based on the brightness standard value and the distance.

[0013] In some embodiments, determining whether the light spot is an abnormal light spot based on the brightness standard value and the distance includes: determining the total width of the waveform whose brightness value is greater than the brightness standard value; if the total width of the waveform is greater than the spot width of the light spot, and the distance is lower than a preset distance threshold, determining that the light spot is an abnormal light spot.

[0014] In some embodiments, the method further includes: when the current environment is a normal environment, or when the current environment is a strong light environment and the light spot is judged to be a normal light spot, outputting light spot information, wherein the light spot information includes at least the light spot centroid and the light spot brightness.

[0015] To solve the above technical problems, in the second aspect, a stray light filtering device is provided in an embodiment of the present invention, which is applied to a laser radar. The device includes: an acquisition unit, used to obtain the light spot data received by the laser radar in the current environment, and extract the light spot from the light spot data; a first judgment unit, used to judge whether the current environment is a strong light environment according to the light spot and the light spot data; a second judgment unit, used to judge whether the light spot is an abnormal light spot with abnormal energy distribution and / or abnormal waveform when the current environment is a strong light environment; and a filtering unit, used to filter the abnormal light spot as an invalid light spot.

[0016] To solve the above technical problems, in the third aspect, an embodiment of the present invention provides a laser radar, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method described in the first aspect above.

[0017] To solve the above technical problems, in a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the method described in the first aspect above.

[0018] To solve the above technical problems, in the fifth aspect, an embodiment of the present invention further provides a computer program product, wherein the computer program product comprises a computer program stored on a computer-readable storage medium, wherein the computer program comprises program instructions, and when the program instructions are executed by a computer, the computer executes the method described in the first aspect above.

[0019] Compared with the prior art, the beneficial effects of the present invention are: different from the prior art, the embodiments of the present invention provide a stray light filtering method, device and laser radar. The method first needs to obtain the light spot data received by the laser radar in the current environment, and extract the light spot from the light spot data, and then judge whether the current environment is a strong light environment based on the light spot and the light spot data. When it is a strong light environment, it is determined whether the light spot is an abnormal light spot by judging whether the energy distribution and / or waveform of the light spot is abnormal. When it is determined to be an abnormal light spot, the abnormal light spot is filtered out as an invalid light spot, thereby filtering out the stray light. This stray light filtering method has a small amount of calculation and can achieve a better filtering effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements / modules and steps with the same reference numerals in the drawings are represented as similar elements / modules and steps. Unless otherwise specified, the figures in the drawings do not constitute proportional limitations.

[0021] Figure 1(a) is a light spot diagram and its light spot waveform diagram collected under a normal (non-strong light) environment;

[0022] Figure 1(b) is a spot waveform diagram of a strong light spot in a strong light environment;

[0023] Figure 1(c) is a spot waveform diagram of a laser spot annihilated by excessive brightness of strong light in a strong light environment;

[0024] Figure 1(d) is a spot waveform diagram of a strong light environment where the strong light amplifies the background noise;

[0025] Figure 1(e) is a light spot waveform diagram of strong reflected light generated when strong light is irradiated onto the surface of a highly reflective material in a strong light environment;

[0026] Figure 2 is a schematic diagram of one application environment of the stray light filtering method provided by an embodiment of the present invention;

[0027] Figure 3 is a schematic flow chart of a stray light filtering method provided in Embodiment 1 of the present invention;

[0028] Figure 4 yes Figure 3 A schematic diagram of a sub-process of step S10 in the stray light filtering method shown;

[0029] Figure 5 This is an example diagram of a light spot waveform provided by the first embodiment of the present invention;

[0030] Figure 6 yes Figure 3 A schematic diagram of a sub-process of step S20 in the stray light filtering method shown;

[0031] Figure 7 It is a distribution diagram of the spot data of the spot background brightness and the ratio of the spot peak to the spot background brightness collected in strong light and normal (non-strong light) scenes;

[0032] Figure 8 yes Figure 3 Another sub-process diagram of step S20 in the stray light filtering method is shown;

[0033] Fig. 9 yes Figure 3 A schematic diagram of a sub-process of step S30 in the stray light filtering method shown;

[0034] Fig.10 yes Figure 3 Another sub-process diagram of step S30 in the stray light filtering method is shown;

[0035] Fig.11 is a point cloud comparison diagram obtained by processing without and with the stray light filtering method provided by the embodiment of the present invention;

[0036] Fig.12 is another schematic flow chart of the stray light filtering method provided in the first embodiment of the present invention;

[0037] Fig.13 is a structural schematic diagram of a stray light filtering device provided in Embodiment 2 of the present invention;

[0038] Fig.14 is a schematic structural diagram of another stray light filtering device provided in Embodiment 2 of the present invention;

[0039] Fig.15 It is a schematic diagram of the hardware structure of a laser radar provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0040] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0041] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0042] It should be noted that, if there is no conflict, the various features in the embodiments of the present invention can be combined with each other, all within the scope of protection of this application. In addition, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flow chart, in some cases, the steps shown or described may be performed in a sequence different from the module division in the device or the flow chart. In addition, the words "first", "second", "third", etc. used herein do not limit the data and execution order, but only distinguish the same items or similar items with basically the same functions and effects.

[0043] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification and in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0044] In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0045] At present, different from the spot diagram and spot waveform diagram collected in a conventional environment as shown in Figure 1(a), there are four situations of spot waveform diagrams collected in a strong light environment, as shown in Figure 1(b), Figure 1(c), Figure 1(d), and Figure 1(e): As shown in Figure 1(b), there is no laser spot and only a strong light spot exists, and the waveform diagram shows an irregular and chaotic waveform; as shown in Figure 1(c), the strong light brightness is too high to annihilate the laser spot, such as the case of halogen lamp interference, and the waveform diagram shows a very wide spot; as shown in Figure 1(d), the strong light amplifies the background noise, and the waveform diagram shows the formation of an interference spot similar to the laser spot; as shown in Figure 1(e), the strong light is irradiated on the surface of a highly reflective material object and then reflected to the laser radar to produce an interference spot, and the waveform diagram shows that the peak brightness of the interference spot is higher than the peak brightness of the target spot, that is, the laser spot.

[0046] In order to solve the above-mentioned problem of interference caused by strong light, which makes it difficult to extract effective light spot particles in the light spot diagram, an embodiment of the present invention provides a stray light filtering method, device and laser radar. The method can filter out invalid light spots that do not conform to the Gaussian distribution in a strong light environment, that is, stray light, and this stray light filtering method consumes less computational effort to achieve better filtering effect.

[0047] Figure 2 A schematic diagram of one of the application environments of the stray light filtering method provided in an embodiment of the present invention, wherein the application environment includes: a laser radar 10, an object A, and strong light B.

[0048] The laser radar 10 can emit a laser beam and receive light information and form a spot diagram through a sensor in the camera. The spot diagram includes not only a laser spot formed by the laser beam reflected by object A, but also interference / invalid spots formed by strong light B directly irradiating the sensor (as shown in Figure 1(b) and Figure 1(c)), or interference / invalid spots formed by strong light B reflecting from object A and irradiating the sensor (as shown in Figure 1(e)), or interference / invalid spots formed by strong light B irradiating the sensor through other indirect lighting methods (as shown in Figure 1(d)). The stray light filtering method provided in an embodiment of the present invention can filter out the interference / invalid spots, and the method is executed by the laser radar 10.

[0049] The object A may be an object with a surface having high reflectivity, or other objects. In practical applications, it may be any object that can be measured by the laser radar 10 in an actual scene.

[0050] The strong light B may be natural light, such as sunlight in summer, or artificial light, such as light emitted by a halogen lamp. In practical applications, it may be any strong light source in an actual ranging scene.

[0051] Specifically, the embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0052] Embodiment 1

[0053] The embodiment of the present invention provides a stray light filtering method, which is applied to a laser radar. The laser radar may be the laser radar 10 described in the above application scenario, see Figure 3 , which shows the process of the stray light filtering method provided by an embodiment of the present invention, the method includes but is not limited to the following steps:

[0054] Step S10: acquiring light spot data received by the laser radar in the current environment, and extracting light spots from the light spot data;

[0055] The light spot data is the pixel value of each pixel on the photosensitive film collected by the camera sensor. For example, when the camera sensor uses a 300,000-pixel camera, the photosensitive film has 480*640 pixels. In order to improve data processing efficiency, only 4*640 pixels in the area where the light spot is located and their corresponding pixel values ​​are collected as the light spot data, that is, only the pixel values ​​of 4 rows of pixels are collected, and the specific 4 rows to be collected are calibrated in advance (first find the brightest row, then take 2 rows upwards and 1 row downwards, and determine 4 rows). After obtaining the light spot data, the light spot can be extracted according to the pixel value of each pixel. For example, if the camera sensor is a black and white camera, the pixel value is expressed in grayscale value, and the pixel value is expressed as 0~255, 0 is black, 255 is white, and the pixel point with a grayscale value greater than a certain value and close to 255 is the pixel point of the light spot, thereby extracting the light spot.

[0056] Specifically, see Figure 4 , which shows Figure 3 In a sub-process of step S10 in the stray light filtering method, extracting the light spot from the light spot data includes:

[0057] Step S11: drawing a light spot waveform diagram according to the light spot data, and determining a plurality of candidate light spots from the light spot waveform diagram;

[0058] Step S12: determining the spot centroid and spot width of each candidate spot;

[0059] Step S13: determining the upper limit and lower limit of the spot width corresponding to each candidate spot centroid position according to the spot centroid;

[0060] Step S14: taking the spot with the largest peak value among the candidate spots whose spot widths are within the range defined by the upper limit value and the lower limit value of the spot width as the spot to be extracted;

[0061] Step S15: extracting the light spot to be extracted.

[0062] In the embodiment of the present invention, it is necessary to first extract the light spot to be extracted, and then determine whether the light spot is an abnormal light spot. Specifically, according to the triangulation distance measurement, Where d represents the distance from the light source / object to the lidar, n1 and n2 are calibration parameters (fixed values), and c x Indicates the center of the light spot, that is, the center of the light spot c xWhen the larger the distance is, the smaller the spot width should be. In other words, the order of the distance of the spot relative to the laser radar is inversely correlated with the spot width. Based on this, the spot centroid and spot width of each spot can be extracted, and the centroid position of each spot and the corresponding upper and lower limit values ​​of the spot width can be determined according to the spot centroid, and then whether it is a spot to be extracted can be determined according to the relationship between the spot width and the upper and lower limit values.

[0063] For example, see Figure 5 , which shows an example of a spot waveform. According to the rules summarized above, Figure 5 In the figure, after determining the centroid position of the light spot, we can get the width of the light spot on the left as w1 and the width of the light spot on the right as w2. Assuming Figure 5 Where m is the lower limit of the light spot width, n is the upper limit of the light spot width, and it can be obtained that the light spot width w1 on the left is obviously within the range limited by the upper limit n and the lower limit m of the light spot width. At this time, it can also be obtained that the light spot width w2 of the right wave is obviously not within the range limited by the upper limit n and the lower limit m of the light spot width. Therefore, it can be determined that the light spot on the left is the light spot to be extracted, and then the light spot to be extracted is further judged whether it is in a strong light environment and whether the light spot is abnormal.

[0064] Step S20: judging whether the current environment is a strong light environment according to the light spot and the light spot data; if so, jumping to step S30; if not, jumping to step S50;

[0065] In the embodiment of the present invention, after the light spot and the light spot data are obtained, it is necessary to analyze whether the light spot data is currently collected in a strong light scene according to the light spot and the light spot data; if so, it is necessary to further judge and process the light spot; if not, that is, when the light spot data is not collected in a strong light scene, that is, in a normal scene, it is necessary to jump to step S50 and directly output the light spot information. The light spot can be the light spot to be extracted after being processed as in the above steps S11 to S15. For details, please refer to Figure 6 , which shows Figure 3 A sub-process of step S20 in the stray light filtering method, wherein judging whether the current environment is a strong light environment according to the light spot and the light spot data, includes:

[0066] Step S21: calculating the background brightness of the light spot and the ratio of the light spot peak to the background brightness according to the light spot data;

[0067] Step S22: Determine whether the ratio of the light spot peak value to the background brightness is lower than a preset ratio threshold, and / or whether the background brightness is higher than a preset brightness threshold; if so, jump to step S23; if not, jump to step S24;

[0068] Step S23: Determine that the current environment is a strong light environment;

[0069] Step S24: Determine that the current environment is a normal environment.

[0070] In an embodiment of the present invention, after obtaining the light spot data, a relationship diagram between pixel point coordinates and light intensity, that is, a light spot waveform diagram, can be drawn based on the light spot data, that is, the pixel values ​​of each pixel point mentioned above. The light spot width, the light spot background brightness, and the ratio of the light spot peak to the light spot background brightness can be determined based on the relationship diagram / light spot waveform diagram.

[0071] Please also see Figure 7 , which shows the distribution diagram of the two spot data, the spot background brightness and the ratio of the spot peak to the spot background brightness, collected in the strong light and normal scenes. It is not difficult to see that the background brightness of the spot is significantly different in the strong light and normal scenes, and the ratio of the spot peak to the spot background brightness is also significantly different in the strong light and normal scenes. Therefore, the ratio of the spot peak to the spot background brightness and / or the background brightness can be used to distinguish and judge whether it is a strong light environment, and it can be judged specifically by the following formula:

[0072]

[0073] Among them, scene_type represents the type of environment, and when scene_type=1, it means that the current environment is a strong light environment, when scene_type=0, it means that the current environment is a non-strong light environment / normal environment, bg represents the background brightness, bg_thr represents the preset brightness threshold, peak_bg_ratio represents the ratio of the light spot peak to the light spot background brightness, and pb_ratio_thr represents the preset ratio threshold.

[0074] It should be noted that in the above-mentioned formula for judging the type of environment, the judgment of a strong light environment is based on the two conditions that the ratio of the light spot peak value to the light spot background brightness is lower than a preset ratio threshold and the background brightness is higher than a preset brightness threshold. In some other embodiments, one condition can be selected as the judgment standard for a strong light environment, or other light spot data can be used as the judgment standard, which can be set according to actual needs.

[0075] For further information, see Figure 8 , which shows Figure 3 Another sub-process of step S20 in the stray light filtering method shown, the method further includes:

[0076] Step S25: constructing scenes with two different illuminations, normal light and strong light, and collecting experimental data;

[0077] Step S26: according to the experimental data, setting the preset ratio threshold and / or the preset brightness threshold for determining whether it is a strong light environment.

[0078] In some embodiments, before determining whether the current environment is a strong light environment, two scenes with different illuminations, normal and strong light, can be constructed and a large amount of experimental data can be collected to statistically obtain and socialize the preset ratio threshold and the preset brightness threshold. For example, a halogen lamp with an illumination of 60klux is used to simulate the illumination of 200klux of summer sunlight. After collecting experimental data under normal and strong light conditions, the preset ratio threshold can be set to 10 and the preset brightness threshold can be set to 36. In some other embodiments, an experimental environment can be constructed according to actual needs to obtain the preset ratio threshold and the preset brightness threshold by calculation, without being bound by the limitations of the embodiments of the present invention.

[0079] Step S30: Determine whether the light spot is an abnormal light spot with abnormal energy distribution and / or abnormal waveform; if so, jump to step S40; if not, jump to step S50;

[0080] In the embodiment of the present invention, after determining that the current environment is a strong light environment, it is necessary to analyze the morphology of the light spot, screen out invalid light spots that do not conform to the Gaussian distribution and abnormal light spots with abnormal waveforms, and then filter out the abnormal light spots. When no light spots with abnormal energy distribution and / or abnormal waveforms can be screened out or do not exist, it can directly jump to step S50 to output the light spot information.

[0081] Specifically, on the one hand, see Fig. 9 , which shows Figure 3 In a sub-process of step S30 in the stray light filtering method, the step of determining whether the light spot is an abnormal light spot with abnormal energy distribution and / or abnormal waveform includes:

[0082] Step S31: calculating the average grayscale variation of the background brightness of the light spot within a preset range around the light spot;

[0083] Step S32: determine whether the gray value average variation is higher than a preset gray value average variation threshold; if so, jump to step S33;

[0084] Step S33: determining that the light spot is an abnormal light spot.

[0085] In the embodiment of the present invention, first, it is necessary to determine whether the energy distribution of the light spot conforms to the Gaussian distribution, and screen out the light spots that do not conform to the Gaussian distribution as abnormal light spots, and then filter out the abnormal light spots. The way to screen out the light spots that do not conform to the Gaussian distribution can be determined by counting the average change in the grayscale value of the area around the light spot, and the judgment can be made by calculating the average variation of the grayscale value. The calculation formula of the average variation of the grayscale value is as follows:

[0086]

[0087] Wherein, avg_var represents the average variation of the grayscale value, and img(i) represents the grayscale value of the pixel. Furthermore, the grayscale value of the pixel of the background around the light spot can be extracted through the grayscale value image of the light spot, and the background and the light spot can be distinguished according to the gradient change of the grayscale value.

[0088] Furthermore, after calculating the average variation of the grayscale value of the background brightness around the light spot, an average variation threshold value, that is, the preset grayscale value average variation threshold value avg_var_thr, can be set to determine whether it conforms to the Gaussian distribution. When avg_var>avg_var_thr is satisfied, the currently calculated light spot is marked as an invalid light spot. The specific value of the preset grayscale value average variation threshold value can be adaptively set according to objective conditions such as the brightness of the actual light spot and the background, the accuracy of the sensor, etc.

[0089] On the other hand, see Fig.10 , which shows Figure 3 In another sub-process of step S30 in the stray light filtering method, the step of determining whether the light spot is an abnormal light spot with abnormal energy distribution and / or abnormal waveform further includes:

[0090] Step S34: determining a brightness standard value based on the peak value of the light spot;

[0091] Step S35: obtaining the distance from the center of the light spot to the nearest wave crest boundary;

[0092] Step S36: determining whether the light spot is an abnormal light spot based on the brightness standard value and the distance.

[0093] In the embodiment of the present invention, in addition to the method of determining whether the light spot is abnormal according to the energy distribution of the light spot described in the above steps S31 to S33, it is also possible to determine whether the waveform of the light spot is abnormal according to the pixel distance between the light spot and the nearest wave crest. The brightness standard value may be a certain percentage of the peak value of the light spot, for example, the brightness standard value is 75% of the peak value of the light spot, which can be set according to actual conditions.

[0094] Specifically, determining whether the light spot is an abnormal light spot based on the brightness standard value and the distance includes: determining a total waveform width w whose brightness value is greater than the brightness standard value; if the total waveform width w is greater than the spot width spot_w of the light spot, and the distance d is lower than a preset distance threshold d_thr, determining that the light spot is an abnormal light spot, that is, the judgment can be made by the following judgment formula:

[0095]

[0096] Among them, scene_type=1 indicates that the current environment is a strong light environment. When filter=1, it means that the total width w of each light spot in the strong light environment is greater than the spot width spot_w or the distance d from the center of the light spot to the nearest peak boundary is lower than the preset distance threshold d_thr. At this time, filter=1 is output and the corresponding light spot is marked as an abnormal light spot.

[0097] The preset distance threshold d_thr is a minimum distance threshold that can be set, and can be set according to actual conditions. Figure 5 In the example shown, the total width w is the sum of the widths of the left light spot w1 and the right light spot w2, that is, the total width w=w1+w2. It is judged whether the total width w is greater than the light spot width spot_w to determine whether it is an abnormal light spot. The specific calculation of the total width w can be calculated based on the actually collected light spot data and the drawn light spot waveform diagram.

[0098] It should be noted that in the above formula for judging whether it is an abnormal light spot, the judgment of the abnormal light spot is based on the premise of determining that the current environment is a strong light environment. The light spot can be determined to be an invalid light spot if either of the two judgment conditions, i.e., judging whether the total width w of the light spot is greater than the light spot width spot_w and judging whether the distance d from the center of the light spot to the nearest wave crest boundary is lower than the preset distance threshold d_thr, is satisfied. In some other embodiments, other light spot data can be used as the judgment standard, or the two judgment conditions can be set to be satisfied together, etc., which can be set according to actual needs.

[0099] Furthermore, under normal conditions, the closer the distance, the larger the light spot should be (the larger the light spot width), the greater the brightness, and the farther the distance, the smaller the light spot should be (the smaller the light spot width), and the lower the brightness. Figure 5 In the figure, the center of the spot of the right wave is larger and farther away from the laser radar. The width w2 of the spot of the right wave should be smaller than the width w1 of the spot on the left. Obviously, Figure 5 The width w2 of the light spot of the middle right wave is larger, which does not conform to the rule that the order of distance should be inversely correlated with the light spot width. Therefore, the right wave can also be judged as an abnormal light spot.

[0100] Step S40: filtering the abnormal light spots as invalid light spots.

[0101] In the embodiment of the present invention, after the abnormal light spots are screened out in the above step S30, it is further necessary to filter the abnormal light spots as invalid light spots. Fig.11 As shown, it is a comparison diagram of point clouds obtained by using and not using the stray light filtering method provided by the embodiment of the present invention, wherein the left figure is a point cloud diagram not processed by the stray light filtering method provided by the embodiment of the present invention, and the light spots in the left figure close to the center of the cross mark line that do not form a straight line are invalid light spots / stray light / noise points, and the right figure is a point cloud diagram processed by the stray light filtering method provided by the embodiment of the present invention. It is not difficult to see that the stray light filtering method provided by the embodiment of the present invention can effectively filter invalid light spots / stray light / noise points, and the filtering effect is good.

[0102] For further information, see Fig.12 , which shows another process of the stray light filtering method provided by an embodiment of the present invention, the method further includes:

[0103] Step S50: outputting light spot information, wherein the light spot information at least includes the light spot centroid and the light spot brightness.

[0104] In an embodiment of the present invention, when it is determined through step S20 that the current environment is not a strong light environment, that is, it is determined to be the current normal environment, and / or when it is determined that there is no light spot with abnormal energy distribution and / or abnormal waveform, the light spot information can be directly output, and the light spot information includes at least the light spot centroid and the light spot brightness.

[0105] After determining that the current environment is a strong light environment through step S20, jump to step S30 to determine whether there are spots with abnormal energy distribution and / or abnormal waveforms. When it is determined that there are spots with abnormal energy distribution and / or abnormal waveforms, the abnormal spots are screened out and filtered out through step S40, and finally the retained spot information is output after the abnormal spots are filtered out. The retained spots are the remaining spots that are retained in the initial spot data except for the invalid spots that are filtered out. The invalid spots that are filtered out are discarded, and the corresponding points in the point cloud are also discarded, so that the following can be obtained: Fig.11 The point cloud image on the right does not contain invalid light spots.

[0106] Embodiment 2

[0107] The embodiment of the present invention provides a stray light filtering device, which can be applied to laser radar. Fig.13, which shows the structure of a stray light filtering device provided by an embodiment of the present invention. The stray light filtering device 100 includes: a collection unit 110, a first judgment unit 120, a second judgment unit 130 and a filtering unit 140.

[0108] The acquisition unit 110 is used to obtain the light spot data received by the laser radar in the current environment and extract the light spot from the light spot data; the first judgment unit 120 is used to judge whether the current environment is a strong light environment based on the light spot and the light spot data; the second judgment unit 130 is used to judge whether the light spot is an abnormal light spot with abnormal energy distribution and / or abnormal waveform when the current environment is a strong light environment; the filtering unit 140 is used to filter the abnormal light spot as an invalid light spot when the light spot is an abnormal light spot.

[0109] In some embodiments, the first judgment unit 120 is also used to calculate the background brightness of the light spot and the ratio of the light spot peak to the background brightness based on the light spot data; determine whether the ratio of the light spot peak to the background brightness is lower than a preset ratio threshold, and / or whether the background brightness is higher than a preset brightness threshold; if so, determine that the current environment is a strong light environment.

[0110] In some embodiments, see Fig.14 , which shows the structure of another stray light filtering device provided by an embodiment of the present invention, the stray light filtering device 100 also includes: an experimental unit 150, used to construct scenes with two different illuminations, conventional light and strong light, and collect experimental data; according to the experimental data, the preset ratio threshold and / or the preset brightness threshold for determining whether it is a strong light environment is set.

[0111] In some embodiments, the acquisition unit 110 is also used to draw a spot waveform diagram according to the spot data, determine multiple candidate spots from the spot waveform diagram; determine the spot centroid and spot width of each candidate spot; determine the upper and lower limits of the spot width corresponding to the centroid position of each candidate spot according to the spot centroid; take the spot with the largest peak value among the candidate spots whose spot width is within the range defined by the upper and lower limits of the spot width as the spot to be extracted; and extract the spot to be extracted.

[0112] In some embodiments, the second judgment unit 130 is further used to calculate the average grayscale value variation of the background brightness of the light spot within a preset range around the light spot; determine whether the average grayscale value variation is higher than a preset average grayscale value variation threshold; if so, determine that the light spot is an abnormal light spot.

[0113] In some embodiments, the second judgment unit 130 is further used to determine a brightness standard value based on the peak value of the light spot; obtain the distance from the center of the light spot to the nearest peak boundary; and determine whether the light spot is an abnormal light spot based on the brightness standard value and the distance.

[0114] In some embodiments, the second judgment unit 130 is further used to determine the total width of the waveform whose brightness value is greater than the brightness standard value; if the total width of the waveform is greater than the spot width of the light spot and the distance is lower than a preset distance threshold, the light spot is determined to be an abnormal light spot.

[0115] In some embodiments, see Fig.14 The stray light filtering device 100 also includes: an output unit 160, which is used to output light spot information when the current environment is a normal environment, or when the current environment is a strong light environment and the light spot is judged to be a normal light spot, wherein the light spot information at least includes the light spot centroid and the light spot brightness.

[0116] Embodiment 3

[0117] The present invention also provides a laser radar. Fig.15 , which shows that it is possible to execute Figures 3 to 12 The hardware structure of the laser radar of the stray light filtering method. The laser radar 10 can be Figure 2 The laser radar 10 is shown.

[0118] The laser radar 10 includes: at least one processor 11; and a memory 12 connected to the at least one processor 11 for communication. Fig.15 The memory 12 stores instructions that can be executed by the at least one processor 11, and the instructions are executed by the at least one processor 11 so that the at least one processor 11 can perform the above Figures 3 to 12 The processor 11 and the memory 12 may be connected via a bus or other means. Fig.15 The example of connecting through bus is taken in the following.

[0119] The memory 12 is a non-volatile computer-readable storage medium that can be used to store non-volatile software programs, non-volatile computer executable programs and modules, such as program instructions / modules corresponding to the stray light filtering method in the embodiment of the present application, for example, Figure 13 to Figure 14 The processor 11 executes various functional applications and data processing of the server by running the non-volatile software programs, instructions and modules stored in the memory 12, that is, implements the stray light filtering method of the above method embodiment.

[0120] The memory 12 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application required by at least one function; the data storage area may store data created according to the use of the stray light filtering device, etc. In addition, the memory 12 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 12 may optionally include a memory remotely arranged relative to the processor 11, and these remote memories may be connected to the stray light filtering device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0121] The one or more modules are stored in the memory 12, and when executed by the one or more processors 11, perform the stray light filtering method in any of the above method embodiments, for example, perform the above described Figures 3 to 12 Steps to achieve Figure 13 to Figure 14 The functions of each module and unit in it.

[0122] The above-mentioned product can execute the method provided in the embodiment of the present application, and has the functional modules and beneficial effects corresponding to the execution method. For technical details not fully described in this embodiment, please refer to the method provided in the embodiment of the present application.

[0123] The present application also provides a non-volatile computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are executed by one or more processors, for example, to execute the above-described Figures 3 to 12 Steps to achieve Figure 13 to Figure 14 The functions of each module in.

[0124] The present application also provides a computer program product, including a computer program stored on a non-volatile computer-readable storage medium, wherein the computer program includes program instructions. When the program instructions are executed by a computer, the computer executes the stray light filtering method in any of the above method embodiments, for example, executing the above described Figures 3 to 12 Steps to achieve Figure 13 to Figure 14 The functions of each module in.

[0125] The embodiments of the present invention provide a stray light filtering method, device and laser radar. The method first needs to obtain the light spot data received by the laser radar in the current environment, and extract the light spot from the light spot data, and then judge whether the current environment is a strong light environment based on the light spot and the light spot data. When it is a strong light environment, it is determined whether the light spot is an abnormal light spot by judging whether the energy distribution and / or waveform of the light spot is abnormal. When it is determined to be an abnormal light spot, the abnormal light spot is filtered out as an invalid light spot, thereby filtering out the stray light. This stray light filtering method has a small amount of calculation and can achieve a better filtering effect.

[0126] It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0127] Through the description of the above implementation methods, ordinary technicians in this field can clearly understand that each implementation method can be implemented by means of software plus a general hardware platform, and of course, it can also be implemented by hardware. Ordinary technicians in this field can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing related 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. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A stray light filtering method, It is characterized in that Applied to laser radar, the method comprises: Acquire the light spot data received by the laser radar in the current environment, and extract the light spot from the light spot data; Determining whether the current environment is a strong light environment according to the light spot and the light spot data; If it is determined to be a strong light environment, determining whether the light spot is an abnormal light spot with abnormal energy distribution and / or abnormal waveform; If it is determined to be an abnormal light spot, the abnormal light spot is filtered as an invalid light spot; Wherein, the determining whether the light spot is an abnormal light spot with abnormal energy distribution and / or abnormal waveform includes: Calculate the average grayscale value variation of the background brightness of the light spot within a preset range around the light spot; Determine whether the gray value average variation is higher than a preset gray value average variation threshold; If so, it is determined that the light spot is an abnormal light spot.

2. The stray light filtering method according to claim 1, It is characterized in that The determining whether the current environment is a strong light environment according to the light spot and the light spot data includes: Calculate the background brightness of the light spot and the ratio of the light spot peak to the background brightness according to the light spot data; Determine whether the ratio of the light spot peak value to the background brightness is lower than a preset ratio threshold, and / or whether the background brightness is higher than a preset brightness threshold; If so, determine that the current environment is a strong light environment.

3. The stray light filtering method according to claim 2, It is characterized in that The method further comprises: Construct scenes with different illumination levels, normal light and strong light, and collect experimental data; The preset ratio threshold and / or the preset brightness threshold for determining whether the environment is a strong light environment is set according to the experimental data.

4. The stray light filtering method according to claim 1, It is characterized in that The extracting the light spot from the light spot data comprises: Draw a spot waveform diagram according to the spot data, and determine a plurality of candidate spots from the spot waveform diagram; Determine the spot centroid and spot width of each candidate spot; According to the light spot centroid, determining the upper limit and lower limit of the light spot width corresponding to each candidate light spot centroid position; The light spot with the largest peak value among the candidate light spots whose light spot width is within the range defined by the upper limit value and the lower limit value of the light spot width is taken as the light spot to be extracted; Extract the light spot to be extracted.

5. The stray light filtering method according to claim 1, It is characterized in that The step of determining whether the light spot is an abnormal light spot with abnormal energy distribution and / or abnormal waveform also includes: Determine a brightness standard value based on the peak value of the light spot; Obtaining the distance from the center of the light spot to the nearest wave crest boundary; Whether the light spot is an abnormal light spot is determined based on the brightness standard value and the distance.

6. The stray light filtering method according to claim 5, It is characterized in that The determining whether the light spot is an abnormal light spot based on the brightness standard value and the distance includes: Determine the total width of the waveform whose brightness value is greater than the brightness standard value; If the total waveform width is greater than the spot width of the light spot, and the distance is lower than a preset distance threshold, the light spot is determined to be an abnormal light spot.

7. The stray light filtering method according to any one of claims 1 to 6, It is characterized in that The method further comprises: When the current environment is a normal environment, or when the current environment is a strong light environment and the light spot is determined to be a normal light spot, light spot information is output, wherein the light spot information at least includes the light spot centroid and the light spot brightness.

8. A stray light filtering device, It is characterized in that Applied to laser radar, the device comprises: An acquisition unit, used for acquiring light spot data received by the laser radar in the current environment, and extracting light spots from the light spot data; A first judging unit, configured to judge whether the current environment is a strong light environment according to the light spot and the light spot data; A second judgment unit is used to judge whether the light spot is an abnormal light spot with abnormal energy distribution and / or abnormal waveform when the current environment is a strong light environment; A filtering unit, used for filtering the abnormal light spot as an invalid light spot; Wherein, the second judgment unit is also used for Calculate the average grayscale value variation of the background brightness of the light spot within a preset range around the light spot; Determine whether the gray value average variation is higher than a preset gray value average variation threshold; If so, it is determined that the light spot is an abnormal light spot.

9. A laser radar, It is characterized in that include: at least one processor; as well as, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 7.

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