Laser radar detection system and method

Abstract

The present application relates to a laser radar detection system and method thereof, comprising a polarized light source, a reflected light deflector, a first polarization beam splitter, a scanning galvanometer, a first detector, a second detector and a processor; a polarized light beam emitted by the polarized light source is sequentially projected to different detection points on a detection surface after passing through the reflected light deflector, the first polarization beam splitter and the scanning galvanometer; the first polarization beam splitter divides the reflected light of the polarized light beam reflected by each detection point into a first polarization state reflected light emitted along a first direction and a second polarization state reflected light emitted along a second direction; the first detector generates first detection data based on the first polarization state reflected light; the second detector generates second detection data based on the second polarization state reflected light; the processor determines the difference between the detection signal value formed by the first detection data and the second detection data and the preset value of the light source, and generates a detection result for the detection surface based on the differences corresponding to each detection point in the detection surface.

Description

Technical Field

[0001] The present application relates to the field of laser radar technology, and in particular to a laser radar detection system and method thereof. Background Art

[0002] LiDAR is a radar system that works in the near-infrared band and was first seen in the field of remote sensing. In recent years, with the development of autonomous driving technology, LiDAR has gradually developed in the automotive field as a high-precision detection method. When LiDAR is working, it emits a modulated laser beam to the target to be detected. When the target is irradiated by the laser beam, it will produce some reflected light. After the reflected light is received by the LiDAR detector, it will be converted into an electrical signal and input into the processing circuit.

[0003] Existing LiDAR products (such as AGV (Automated Guided Vehicle) and unmanned robots for logistics) have a single detection dimension and may misidentify obstacles such as glass, smooth ground, and water. For light in different polarization states, current detection solutions are relatively rigid or have a single information dimension, which causes the incident light to pass through different materials or different angles (the angle of the target surface relative to the LiDAR) and the intensity after being reflected by the target does not meet expectations, resulting in distance analysis errors. Summary of the invention

[0004] Based on this, it is necessary to provide a lidar detection system and method that can increase the polarization detection dimension and reduce the probability of recognition errors in response to the above-mentioned technical problems.

[0005] In a first aspect, the present application provides a laser radar detection system, including a polarized light source, a reflected light deflector, a first polarization beam splitter, a scanning galvanometer, a first detector, a second detector, and a processor;

[0006] The polarized light source is used to emit a polarized light beam having a first polarization state, and the polarized light beam is sequentially passed through the reflected light deflector, the first polarization beam splitter and the scanning galvanometer and then projected onto the detection surface;

[0007] The scanning galvanometer is used to project the incident polarized light beam to different detection points on the detection surface;

[0008] The first polarization beam splitter is used to transmit the polarized light beam and to split the reflected light of the polarized light beam reflected by each detection point into a first polarization state reflected light emitted in a first direction and a second polarization state reflected light emitted in a second direction;

[0009] The reflected light in the first polarization state is incident on the first detector after being changed in direction by the reflected light deflector;

[0010] The first detector is used to receive the first polarization state reflected light and generate first detection data according to the first polarization state reflected light;

[0011] The second detector is used to receive the second polarization state reflected light and generate second detection data according to the second polarization state reflected light;

[0012] The processor is electrically connected to the first detector and the second detector, and is used to determine the difference between the detection signal value formed by the first detection data and the second detection data and the preset value of the light source, and generate a detection result for the detection surface according to the difference corresponding to each detection point in the detection surface.

[0013] In one of the embodiments, the polarization direction of the polarized light beam is consistent with the polarization direction of the first polarization beam splitter.

[0014] In one of the embodiments, the reflected light deflector comprises a non-polarizing circulator, and the non-polarizing circulator comprises a reflector, a beam splitter, a first birefringent crystal, a Faraday rotator, a first half-wave plate, and a second birefringent crystal;

[0015] The first polarization state reflected light passes through the second birefringent crystal, the first half wave plate, the Faraday rotator and the first birefringent crystal in sequence and is projected onto the reflector and the beam splitter. The reflector is used to reflect the incident light to the beam splitter so that the beam splitter projects the incident first polarization state reflected light to the first detector.

[0016] In one of the embodiments, the reflected light deflector comprises a second polarization beam splitter and a second half-wave plate sequentially arranged along an outgoing optical path of the polarized light beam;

[0017] The second half wave plate is used to convert the first polarization state reflected light into the second polarization state reflected light;

[0018] The second polarization beam splitter is used for transmitting the light in the first polarization state and reflecting the light in the second polarization state, so as to transmit the reflected light in the second polarization state to the first detector.

[0019] In one of the embodiments, a quarter wave plate is further included, and the quarter wave plate is arranged on the light incident surface of the first polarization beam splitter for receiving the reflected light.

[0020] In one of the embodiments, the laser radar further includes a first collimation component and a second collimation component;

[0021] The first collimating component is arranged on the optical path between the polarized light source and the reflected light deflector, and is used to collimate the polarized light beam;

[0022] The second collimating component is disposed on the optical path between the first polarization beam splitter and the second detector, and is used for collimating the reflected light of the second polarization state.

[0023] In a second aspect, the present application further provides a laser radar detection method, which is implemented by the laser radar detection system as described above; the laser radar detection method comprises:

[0024] Controlling the polarized light source to emit a polarized light beam having a first polarization state with a preset pulse;

[0025] Determine the difference between the detection signal value corresponding to each detection point in the detection surface and the preset value of the light source, and generate the detection result of the detection surface according to the difference corresponding to each detection point; the detection signal value is formed by the first detection data of each detection point in the detection surface generated by the first detector based on the polarized light beam and the second detection data of each detection point in the detection surface generated by the second detector based on the polarized light beam.

[0026] In one embodiment, the detection result includes distance information of each detection point; the preset value of the polarized light source is a preset polarization extinction ratio of the light source; judging the difference between the detection signal value corresponding to a detection point in the detection surface and the preset value of the light source, and generating the detection result of the detection surface according to the difference corresponding to the detection point, including:

[0027] Acquire an actual polarization extinction ratio of a light source according to the first detection data and the second detection data corresponding to a detection point;

[0028] Comparing the actual polarization extinction ratio of the polarized light source with the preset polarization extinction ratio of the light source;

[0029] If the difference between the actual polarization extinction ratio of the polarized light source and the preset polarization extinction ratio of the light source is less than a preset threshold, the final distance information corresponding to the detection point is output according to the detection data output by the main detector; the main detector is one of the first detector and the second detector that receives more light beam energy when the detection surface has no polarization state change effect on the polarized light beam.

[0030] In one embodiment, the determining the difference between a detection signal value corresponding to a detection point on the detection surface and a preset value of the light source, and generating a detection result for the detection surface according to the difference corresponding to the detection point, further includes:

[0031] When the difference between the actual polarization extinction ratio of the light source and the preset polarization extinction ratio of the light source is greater than a preset threshold, outputting first distance information and second distance information according to the first detection data and the second detection data respectively;

[0032] Comparing the actual polarization extinction ratio of the light source with a preset light source polarization information list table to determine the type of the detection surface;

[0033] One of the first distance information and the second distance information is selected according to the type of the detection surface as the final distance information of the detection point.

[0034] In one embodiment, the preset light source polarization information list table includes a correspondence between multiple sets of detection surface types and selection rules; and selecting one of the first distance information and the second distance information as the final distance information according to the type of the detection surface includes:

[0035] According to the type of the detection surface, a selection rule corresponding to the type of the detection surface is matched in the preset light source polarization information list; the selection rule includes selecting closer distance information and selecting farther distance information;

[0036] One of the first distance information and the second distance information is selected as final distance information according to the matched selection rule.

[0037] The laser radar detection system and method thereof, by setting a first polarization beam splitter in the laser radar, the first polarization beam splitter can transmit light of a first polarization state and reflect light of a second polarization state, based on which the first polarization beam splitter can detect reflected light reflected from a polarized light beam emitted by a polarized light source and divide it into reflected light of a first polarization state emitted in a first direction and reflected light of a second polarization state emitted in a second direction. Furthermore, by setting a reflected light deflector capable of changing the direction of reflected light of a first polarization state on the light emitting surface of the first polarization beam splitter from which reflected light of a first polarization state is emitted, the reflected light of a first polarization state can be projected onto the first detector. The second polarization state reflected light emitted by the first polarization beam splitter is projected onto the second detector. Therefore, when the detection surface has different reflectivity to light beams in different polarization states, the reflected light in different polarization states will enter the corresponding detector after passing through the first polarization beam splitter, so that the energy of the reflected light in the two polarization states can be collected. That is, the laser radar in the present application has more detection dimensions, and further judges the difference between the detection signal value formed by the detection data corresponding to the reflected light in the two polarization states and the preset value of the light source through the processor, and generates the detection result of the detection surface according to the difference, which can effectively improve the detection accuracy of the detection surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions 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 related drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 This is one of the structural schematic diagrams of a laser radar in one embodiment;

[0040] Figure 2 is a schematic structural diagram of a non-polarization circulator in one embodiment;

[0041] Figure 3 This is a second schematic diagram of the structure of a laser radar in one embodiment;

[0042] Figure 4 This is a third structural diagram of a laser radar in one embodiment;

[0043] Figure 5 is a schematic flow chart of a laser radar detection method in an embodiment;

[0044] Figure 6 One of the flow charts of determining the difference between a detection signal value corresponding to a detection point on a detection surface and a preset value of a light source, and generating a detection result for the detection surface according to the difference corresponding to a detection point in an embodiment;

[0045] Figure 7 The second flow chart of determining the difference between a detection signal value corresponding to a detection point on a detection surface and a preset value of a light source, and generating a detection result for the detection surface according to the difference corresponding to the detection point, in one embodiment;

[0046] Figure 8 A schematic diagram of a flow chart of selecting one of the first distance information and the second distance information as the final distance information according to the type of the detection surface in an embodiment;

[0047] Fig. 9 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment.

[0048] Description of reference numerals:

[0049] Polarized light source: 110; reflected light deflector: 120; non-polarized circulator: 121; reflector: 1211; beam splitter: 1212; first birefringent crystal: 1213; Faraday rotator: 1214; half wave plate: 1215; second birefringent crystal: 1216; first polarization beam splitter: 130; scanning galvanometer: 140; first detector: 150; second detector: 160; processor: 170; detection surface: 180; quarter wave plate: 190; first collimation component: 1100; second collimation component: 1200. DETAILED DESCRIPTION

[0050] 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.

[0051] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0052] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0053] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0054] In one embodiment, see the attached Figure 1 , attached Figure 1 One of the structural schematic diagrams of the laser radar in an embodiment of the present application is shown. The laser radar in this embodiment includes a polarized light source 110, a reflected light deflector 120, a first polarization beam splitter 130, a scanning galvanometer 140, a first detector 150, a second detector 160 and a processor 170; the polarized light source 110 is used to emit a polarized light beam in a first polarization state, and the polarized light beam passes through the reflected light deflector 120, the first polarization beam splitter 130 and the scanning galvanometer 140 in sequence and is projected to the detection surface 180; the scanning galvanometer 140 is used to project the incident polarized light beam to different detection points on the detection surface 180; the first polarization beam splitter 130 is used to transmit light in a first polarization state, and divide the reflected light of each detection point to the polarized light beam into a first polarization state emitted in a first direction. polarized state reflected light and second polarized state reflected light emitted along the second direction; the first direction and the second direction are perpendicular to each other; the first polarized state reflected light is changed in direction by the reflected light deflector 120 and is incident on the first detector 150; the first detector 150 is used to receive the first polarized state reflected light, and generate first detection data according to the first polarized state reflected light; the second detector 160 is used to receive the second polarized state reflected light, and generate second detection data according to the second polarized state reflected light; the processor 170 is electrically connected to the first detector 150 and the second detector 160, and is used to determine the difference between the detection signal value formed by the first detection data and the second detection data and the preset value of the light source, and generate the detection result of the detection surface 180 according to the difference corresponding to each detection point in the detection surface 180.

[0055] Among them, the polarized light source 110 refers to a laser light source that can emit a polarized light beam, that is, the polarized light beam emitted by the polarized light source 110 in this embodiment has a single polarization state, for example, it can refer to a linearly polarized laser beam or a circularly polarized laser beam, that is, the first polarization state and the second polarization state in this application can refer to a linear polarization state and a circular polarization state, respectively. Exemplarily, the above-mentioned polarized light source 110 can be a VCSEL (Vertical Cavity Surface Emitting Laser) light source, and the polarization extinction ratio of the output light of the VCSEL light source chip can be>16dB.

[0056] In order to improve the overall energy efficiency of the laser radar in this embodiment, the above-mentioned reflected light deflector 120 can be a non-polarized circulator based on a Faraday rotator or other optical polarization components (such as optical components including a polarization beam splitter and a half wave plate). Taking the optical circulator based on a Faraday rotator as an example, the optical circulator based on a Faraday rotator only allows the light beam to be transmitted in one direction, and the reflected light will be offset. Therefore, the optical path in the laser radar in this embodiment can be shared, and there is no need to cut the beam, which can avoid wasting beam energy. It can be seen that the laser radar in this embodiment can use a lower power light source to achieve the same effect.

[0057] The polarization direction of the first polarization beam splitter 130 is consistent with the polarization direction of the polarized light beam in the first polarization state, that is, the polarization direction of the first polarization beam splitter 130 is parallel to the polarization direction of the polarized light beam. For example, if the first polarization state of the polarized light beam is the S polarization state, then the polarization direction of the first polarization beam splitter 130 is also the S polarization state. In actual operation, the polarization direction of the light source and the polarization direction of the first polarization beam splitter 130 should be adjusted to be parallel in advance, so that the polarized light beam in the first polarization state can be transmitted, and the energy utilization rate of the polarized light source 110 can also be improved. After the polarized light beam of the first polarization state enters the first polarization beam splitter 130 intact, it is deflected to different detection points on the detection surface 180 by the scanning galvanometer 140. Since the polarization direction of the polarized light beam changes after hitting the detection point and returning, after the reflected light with the changed polarization direction is incident on the first polarization beam splitter 130, the first polarization beam splitter 130 will split it into two parts according to the polarization state - the first polarization state reflected light and the second polarization state reflected light, which are acquired by the first detector 150 and the second detector 160 respectively. The first polarization state reflected light and the second polarization state reflected light are mutually orthogonal light beams.

[0058] It can be seen that in this embodiment, since the first polarization beam splitter 130 can only transmit light of the first polarization state, when the detection surface 180 receives the deflected light beam of the first polarization state and reflects the reflected light, the first polarization beam splitter 130 will split the reflected light with different polarization directions into the first polarization state reflected light and the second polarization state reflected light perpendicular to each other, and the first polarization state reflected light is incident on the first detector 150 after being polarized by the reflected light deflector 120, and the second polarization state reflected light is incident on the second detector 160 after being reflected by the first polarization beam splitter 130. Therefore, the laser radar detection system of the present application can collect reflected light of all polarization states, so that the laser radar in this embodiment can obtain target polarization characteristic information in addition to conventional laser radar energy information. Further, the processor 170 can analyze the first detection data generated by the first detector 150 and the second detection data generated by the second detector 160, and obtain the detection result of the detection surface 180 according to the first detection data and the second detection data corresponding to each detection point in the detection surface 180, thereby ensuring the detection accuracy.

[0059] In one embodiment, the polarization direction of the polarized light beam is consistent with the polarization direction of the first polarization beam splitter.

[0060] In this embodiment, the polarization direction of the polarized light beam is consistent with the polarization direction of the first polarization beam splitter, that is, the polarized light beam with the first polarization state emitted by the polarized light source can all pass through the first polarization beam splitter, causing light beams of other polarization states in the polarized light source to be reflected and wasted.

[0061] In one embodiment, the reflective light deflector comprises a non-polarizing circulator.

[0062] In this embodiment, the polarized light beam incident from the polarized light source can be directly transmitted to the first polarization beam splitter through the non-polarization circulator, and the first polarization state reflected light reflected from the detection surface can be reflected to the first detector. In addition, the non-polarization circulator can also ensure that the polarization states of the polarized light beam and the first polarization state reflected light do not change, thereby reducing energy loss and ensuring that the energy of the first polarization state reflected light can be accurately detected by the first detector.

[0063] For details, see the attached Figure 2 , attached Figure 2 The schematic diagram of the structure of the non-polarization circulator 121 in the present embodiment is shown. The non-polarization circulator 121 in the present embodiment includes a reflector 1211, a beam splitter 1212, a first birefringent crystal 1213, a Faraday rotator 1214, a half wave plate 1215, and a second birefringent crystal 1216. The first polarization state reflected light passes through the second birefringent crystal 1216, the half wave plate 1215, the Faraday rotator 1214, and the first birefringent crystal 1213 in sequence and is projected to the reflector 1211 and the beam splitter 1212. The reflector 1211 is used to reflect the incident light to the beam splitter 1212, so that the beam splitter 1212 projects the incident first polarization state reflected light to the first detector 150.

[0064] For incident polarized beams, see Appendix Figure 2 In Figure (a), the polarized light beam does not pass through the reflector 1211 and the beam splitter 1212, but directly passes through the first birefringent crystal 1213, the Faraday rotator 1214, the half wave plate 1215 and the second birefringent crystal 1216 in sequence and is projected to the first polarization beam splitter.

[0065] For the incident first polarization state reflected light, see the attached Figure 2 In Figure (b), the first polarization state reflected light is projected to the half wave plate 1215, the Faraday rotator 1214, and the first birefringent crystal 1213 in sequence through the second birefringent crystal 1216 and is divided into two parts, one of which is projected to the reflector 1211, and the reflector 1211 reflects the incident first polarization state reflected light to the beam splitter 1212; the other part is directly projected to the beam splitter 1212, and the beam splitter 1212 projects all the incident first polarization state reflected light to the first detector 150, so that the reflected light deflector 120 in this embodiment can only allow the polarized light beam to be transmitted in one direction, and the first polarization state reflected light reflected by the detection surface is offset to the first detector 150 through the reflector 1211 and the beam splitter 1212, so that the optical path is shared, avoiding the waste of light beam energy.

[0066] In addition, the non-polarized circulator 121 in this embodiment is provided with two birefringent crystals, which can effectively control the polarization state of light. The first birefringent crystal divides the incident light beam into o-light and e-light, which have different propagation speeds and refraction angles, thereby generating a phase difference. After adjusting the polarization directions of these light beams by the Faraday rotator and the half-wave plate, the second birefringent crystal ensures that the light beams in different polarization states can be efficiently merged to maintain the polarization consistency of the light beams. Therefore, by precisely controlling the merging of o-light and e-light, the directivity and intensity of the light beam can be effectively improved, and energy loss can be reduced.

[0067] In one embodiment, the reflected light deflector includes a second polarization beam splitter and a second half wave plate which are arranged in sequence along the output light path of the polarized light beam; the second half wave plate is used to convert the first polarization state reflected light into the second polarization state reflected light; the second polarization beam splitter is used to transmit the light of the first polarization state and reflect the light of the second polarization state, so as to transmit the second polarization state reflected light to the first detector.

[0068] This embodiment provides a technical solution parallel to the above-mentioned reflective light deflector including a non-polarizing circulator, and the above-mentioned function of the reflective light deflector can also be achieved through a second polarization beam splitter and a second half-wave plate.

[0069] In one embodiment, see the attached Figure 3 , attached Figure 3 The second structural schematic diagram of the laser radar in one embodiment of the present application is shown. The laser radar in this embodiment also includes a quarter-wave plate 190, and the quarter-wave plate 190 is arranged on the light incident surface of the first polarization beam splitter 130 for receiving the reflected light.

[0070] Among them, the quarter wave plate 190 can convert linear polarized light into circular polarized light, or convert circular polarized light into linear polarized light. In this embodiment, a quarter wave plate 190 is further arranged on the light incident surface of the first polarization beam splitter 130 for receiving reflected light, which can also achieve the purpose of the invention of the present application, avoid adding a production line for removing the quarter wave plate 190 on the basis of the existing first polarization beam splitter 130, and can reduce production costs.

[0071] In one embodiment, see the attached Figure 4 , attached Figure 4 The third structural schematic diagram of the laser radar in an embodiment of the present application is shown. The laser radar in this embodiment also includes a first collimation component 1100 and a second collimation component 1200; the first collimation component 1100 is arranged on the optical path between the polarized light source 110 and the reflected light deflector 120, and is used to collimate the polarized light beam; the second collimation component 1200 is arranged on the optical path between the first polarization beam splitter 130 and the second detector 160, and is used to collimate the reflected light of the second polarization state.

[0072] The first collimating assembly 1100 and the second collimating assembly 1200 are used to collimate the received incident light and project it to the subsequent optical device. For example, the first collimating assembly 1100 collimates the received polarized light beam to the reflected light deflector 120, and the second collimating assembly 1200 collimates the received second polarization state reflected light to the second detector 160. Exemplarily, the first collimating assembly 1100 and the second collimating assembly 1200 can both be collimating lens groups.

[0073] In one embodiment, the polarization extinction ratio of the output light of the polarized light source is greater than 16 dB.

[0074] Among them, the polarization extinction ratio of the output light of the polarized light source refers to the proportional relationship between the two orthogonal polarization components decomposed along the direction of the main polarization state, expressed in decibels (dB). The extinction ratio is one of the important indicators to measure the performance of a polarized light source, reflecting the ability of a polarized light source to convert input light into linearly polarized light. Specifically, the higher the extinction ratio, the closer the output light is to linearly polarized light. For example, an extinction ratio of 100:1 is equivalent to 20dB, while an extinction ratio of 10000:1 corresponds to 40dB. In this embodiment, the polarization extinction ratio of the output light of the polarized light source is >16dB, which can ensure the beam energy of the polarized light beam, reduce signal interference and noise caused by unstable polarization state, and ensure the stability of the lidar.

[0075] In one embodiment, the scanning mirror comprises a MEMS or mechanical rotating mirror.

[0076] MEMS (Micro Electro Mechanical System) integrates micro-vibration mirrors, drivers, sensors and other modules on a single silicon-based chip, achieving the advantages of small size, fast scanning frequency and low cost. The mechanical galvanometer drives the overall optical-mechanical structure through a motor to perform 360° rotation scanning, which can achieve all-round and high-precision environmental perception. In practical applications, it is only necessary to ensure that the effect of the application solution can be achieved. Those skilled in the art can flexibly select a suitable scanning galvanometer, which is not limited to the above examples.

[0077] In one embodiment, see the attached Figure 5 , attached Figure 5 The flowchart of the laser radar detection method in one embodiment of the present application is shown. The laser radar detection method in this embodiment is executed by the laser radar in any of the above embodiments. This embodiment is illustrated by applying the method to a terminal. It can be understood that the method can also be applied to a server, and can also be applied to a system including a terminal and a server, and is implemented through the interaction between the terminal and the server. The above laser radar detection method includes the following steps S501 to S502.

[0078] Step S501 , controlling a polarized light source to emit a polarized light beam having a first polarization state with a preset pulse.

[0079] The polarized light beam of the first polarization state passes through the reflected light deflector in the laser radar and is incident on the first polarization beam splitter. The polarization direction of the first polarization beam splitter is consistent with the polarization direction of the polarized light beam of the first polarization state, that is, the polarization direction of the first polarization beam splitter is parallel to the polarization direction of the polarized light beam. Therefore, the polarized light beam of the first polarization state can enter the first polarization beam splitter without loss, and then be deflected to different areas of the detection surface by the scanning galvanometer. The reflected light after the detection surface reflects the polarized light beam has two polarization states, wherein the reflected light of the first polarization state is transmitted through the first polarization beam splitter, and then deflected to the first detector by the reflected light deflector, and the reflected light of the second polarization state is reflected by the first polarization beam splitter to the second detector. Therefore, the first detector can generate the first detection data corresponding to the reflected light of the first polarization state, and the second detector can generate the second detection data corresponding to the reflected light of the second polarization state, that is, the first detection data can represent the reflected light information of the first polarization state, and the second detection data can represent the reflected light information of the second polarization state.

[0080] Step S502, determine the difference between the detection signal value corresponding to each detection point in the detection surface and the preset value of the light source, and generate the detection result of the detection surface according to the difference corresponding to each detection point; the detection signal value is formed by the first detection data of each detection point in the detection surface generated by the first detector based on the polarized light beam and the second detection data of each detection point in the detection surface generated by the second detector based on the polarized light beam.

[0081] Specifically, determining the difference between the detection signal value corresponding to each detection point in the detection surface and the preset value of the light source, and generating the detection result of the detection surface according to the difference corresponding to each detection point also includes: obtaining first detection data generated by the first detector due to receiving the reflected light of the first polarization state, and obtaining second detection data generated by the second detector due to receiving the reflected light of the second polarization state; determining the difference between the detection signal value formed by the first detection data and the second detection data and the preset value of the light source, and generating the detection result of the target detection surface according to the difference.

[0082] It can be understood that the detection signal value is generated by the first detection data and the second detection data, and the first detection data corresponds to the reflected light information of the first polarization state, and the second detection data corresponds to the reflected light information of the second polarization state. Therefore, the detection signal value can represent the reflected light information of the two polarization states, judge the difference between the detection signal value corresponding to each detection point in the detection surface and the preset value of the light source, and generate the detection result of the detection surface according to the difference corresponding to each detection point, so as to detect the detection surface more accurately.

[0083] In addition, after determining the difference between the detection signal value corresponding to a detection point in the detection surface and the preset value of the light source, and generating a detection result of a detection point based on the difference, the scanning galvanometer is controlled to deflect according to the preset deflection angle, and then the detection result of another detection point in the detection surface is obtained according to the same steps of obtaining the detection result. When the scanning galvanometer is at a different deflection angle, it means that the polarized light beam is scanned point by point by the scanning galvanometer according to the predetermined path. Therefore, the scanning galvanometer is controlled to scan point by point, and the detection result of the entire detection surface can be obtained according to the detection result corresponding to each detection point. In addition, the detection result of a single detection point can be the distance information of the detection point, and the distance information of all detection points constitutes the point cloud data of the entire detection surface, that is, the detection result of the entire detection surface.

[0084] In this embodiment, the target detection parameters are obtained based on the reflected light intensity information received by the secondary detector, and the distance information is further obtained based on the target detection parameters. Since the target detection parameters include the reflected light intensity information received by the main detector or the reflected light intensity information received by the main detector and the secondary detector, the distance information can be obtained based on the multi-dimensional detection parameters, thereby improving the accuracy of the obtained distance information.

[0085] In one embodiment, the detection result includes the distance information of each detection point; the preset value of the polarized light source is the preset polarization extinction ratio of the light source; Figure 6 , attached Figure 6 One of the flowchart diagrams of determining the difference between a detection signal value corresponding to a detection point in the detection surface and a preset value of a light source, and generating a detection result for the detection surface according to the difference corresponding to the detection point in this embodiment is shown. In this embodiment, determining the difference between a detection signal value corresponding to a detection point in the detection surface and a preset value of a light source, and generating a detection result for the detection surface according to the difference corresponding to the detection point includes the following steps S601 to S603.

[0086] Step S601, obtaining the actual polarization extinction ratio of the light source according to the first detection data and the second detection data corresponding to a detection point.

[0087] The first detector generates first detection data based on the intensity information of the received reflected light of the first polarization state, and correspondingly, the second detector generates second detection data based on the intensity information of the received reflected light of the second polarization state. It can be understood that when the scanning galvanometer is at each predetermined deflection angle, the first detector and the second detector will both receive the intensity information of the corresponding reflected light. In addition, the intensity information of the reflected light received by the first detector and the second detector can refer to the light intensity information in the form of an optical signal corresponding to the reflected light. The first detector / second detector is based on the information in the form of an electrical signal converted from the reflected light and can reflect the light intensity, such as the electrical parameters corresponding to the light intensity (voltage, current, power, etc.), or it can be the information that can reflect the light intensity after the aforementioned electrical signal is processed by denoising, filtering, amplification, etc., which is the above-mentioned first detection data / second detection data.

[0088] The actual polarization extinction ratio of the above-mentioned light source refers to the ratio of the light intensities of two orthogonal polarization states. The first detection data reflecting the intensity of the reflected light of the first polarization state is obtained by the first detector, and the second detection data reflecting the intensity of the reflected light of the second polarization state is obtained by the second detector. The actual polarization extinction ratio of the above-mentioned light source can be obtained based on the first detection data and the second detection data.

[0089] Step S602: compare the actual polarization extinction ratio of the polarized light source with the preset polarization extinction ratio of the light source.

[0090] Step S603, if the difference between the actual polarization extinction ratio of the polarized light source and the preset polarization extinction ratio of the light source is less than a preset threshold, the final distance information of the corresponding detection point is output according to the detection data output by the main detector; the main detector is one of the first detector and the second detector that receives more light beam energy when the polarized light beam does not undergo a polarization state change effect when detecting the polarized light beam.

[0091] In step S603, regarding the determination of the main detector, when the structure of the laser radar is set, the processor can know which one of the first detector and the second detector is the main detector through a preset program. Figure 1 For the laser radar structure in the embodiment, the first detector is the main detector. Figure 3 For the laser radar structure shown, the second detector is the main detector.

[0092] In addition, when the reflected light intensity information received by another detector (which can be understood as a sub-detector) other than the main detector among the first detector and the second detector is less than the background noise of the sub-detector, it means that the sub-detector has no light beam energy received, and its output signal is the background noise, and the intensity is regarded as 0. At this time, the difference between the actual polarization extinction ratio of the polarized light source and the preset polarization extinction ratio of the light source is less than the preset threshold value, and the distance information of the corresponding detection point can be output according to the first detection data output by the main detector.

[0093] It can be understood that the scanning galvanometer controls the micro-mirror on the cantilever beam through the current, so that it is suspended between a pair of torsion bars in the front, back, left and right. The deflection angle of the scanning galvanometer is proportional to the current, so that the direction of the laser beam can be accurately controlled. The laser beam is reflected by the scanning galvanometer and irradiated onto the object on the detection surface. The distance information of the corresponding detection point can be obtained by measuring the reflected beam of the laser beam, and the distance information of multiple detection points can be obtained by obtaining the reflected beam after the scanning galvanometer deflects the polarized beam point by point. For example, the distance information of each detection point can be obtained by adopting the Itof (indirect time of flight) or dtof (direct time of flight) detection principle and performing distance information solution based on the target detection data.

[0094] In one embodiment, see the attached Figure 7 , attached Figure 7 The second flowchart diagram shows the method of determining the difference between the detection signal value corresponding to a detection point in the detection surface and the preset value of the light source, and generating the detection result for the detection surface according to the difference corresponding to the detection point. The method of determining the difference between the detection signal value corresponding to a detection point in the detection surface and the preset value of the light source, and generating the detection result for the detection surface according to the difference corresponding to the detection point also includes the following steps S701 to S703.

[0095] Step S701: when the difference between the actual polarization extinction ratio of the light source and the preset polarization extinction ratio of the light source is greater than a preset threshold, outputting first distance information and second distance information according to the first detection data and the second detection data respectively.

[0096] When the reflected light intensity information received by another detector (which can be understood as a sub-detector) other than the main detector among the first detector and the second detector is greater than the background noise of the sub-detector, it means that the sub-detector has received the light beam energy, that is, the detection surface has undergone a polarization state change effect on the polarized light beam, that is, the sub-detector has obtained polarization characteristic information that cannot be obtained by conventional laser radars. If the difference between the actual polarization extinction ratio of the light source and the preset polarization extinction ratio of the light source is greater than the preset threshold, the distance information of the detection point can be obtained based on the detection data of the main detector and the detection data of the sub-detector.

[0097] Step S702: Compare the actual polarization extinction ratio of the light source with the preset light source polarization information list to determine the type of the detection surface.

[0098] The type of the detection surface may refer to the material of the detection surface, such as water, glass, plastic film, etc., but is not limited thereto.

[0099] Step S703: selecting one of the first distance information and the second distance information as the final distance information of the detection point according to the type of the detection surface.

[0100] In this embodiment, when the difference between the actual polarization extinction ratio of the light source and the preset polarization extinction ratio of the light source is greater than the preset threshold value, the first distance information and the second distance information are output according to the first detection data and the second detection data, and the actual polarization extinction ratio of the light source is compared with the preset light source polarization information list table, and the type of the detection surface is determined according to the comparison result, and one of the first distance information and the second distance information is further selected according to the type of the detection surface as the final distance information of the detection point. Therefore, the distance information of each detection point on the detection surface is determined based on the type of the detection surface, which can improve the detection accuracy.

[0101] In one embodiment, the preset light source polarization information list table includes a plurality of sets of corresponding relationships between the types of detection surfaces and the selection rules; see the attached Figure 8 , attached Figure 8 A schematic diagram of a process of selecting one of the first distance information and the second distance information as the final distance information according to the type of the detection surface is shown. In this embodiment, the process of selecting one of the first distance information and the second distance information as the final distance information according to the type of the detection surface includes the following steps S801 to S802.

[0102] Step S801, matching the selection rule corresponding to the type of the detection surface in the preset light source polarization information list according to the type of the detection surface; the selection rule includes selecting closer distance information and selecting farther distance information.

[0103] The preset light source polarization information list table has preset distance information selection rules corresponding to the type of detection surface. For example, the first detection surface type selects the closer (smaller) one of the first distance information and the second distance information, and the second detection surface type selects the farther (larger) one of the first distance information and the second distance information.

[0104] Step S802: selecting one of the first distance information and the second distance information as final distance information according to the matched selection rule.

[0105] In this embodiment, a selection rule corresponding to the type of detection surface is matched in a preset light source polarization information list table according to the type of detection surface, and one of the first distance information and the second distance information is selected as the final distance information according to the matched selection rule. This can ensure that the distance information of the detection point actually detected corresponds to the type of detection surface, thereby improving the accuracy of detection.

[0106] It should be understood that, although the steps in the flowcharts involved in the embodiments described above are displayed in sequence as indicated by the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless clearly stated in this article, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. For example, the step of controlling the scanning galvanometer to polarize the light beam point by point can be to perform an angle shift after obtaining the distance information of the detection point corresponding to a polarization angle, repeat the step of obtaining the distance information in the laser radar detection method of the present application, obtain the distance information of the corresponding detection point after the angle shift, and complete the scanning of all detection points in sequence, thereby obtaining point cloud data; it can also be to complete the scanning of all polarization angles before analyzing the reflected light intensity information corresponding to a single detection point, and then analyze the reflected light intensity information corresponding to each polarization angle respectively, thereby obtaining point cloud data at one time. Moreover, at least a part of the steps in the flowcharts involved in the embodiments described above may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily sequentially, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0107] Based on the same inventive concept, the embodiment of the present application also provides a laser radar detection device for implementing the laser radar detection method involved above. The implementation solution provided by the device to solve the problem is similar to the implementation solution recorded in the above method, so the specific limitations in one or more laser radar detection device embodiments provided below can refer to the limitations of the laser radar detection method above, and will not be repeated here.

[0108] In an exemplary embodiment, the present application provides a laser radar detection device, comprising: a control module and a signal processing module. The control module is used to control the polarized light source to emit a polarized light beam in a first polarization state with a preset pulse; the signal processing module is used to determine the difference between the detection signal value corresponding to each detection point in the detection surface and the preset value of the light source, and generate a detection result for the detection surface according to the difference corresponding to each detection point; the detection signal value is formed by the first detection data of each detection point in the detection surface generated by the first detector based on the polarized light beam and the second detection data of each detection point in the detection surface generated by the second detector based on the polarized light beam.

[0109] In an exemplary embodiment, the detection result includes distance information of each detection point; the preset value of the polarized light source is a preset polarization extinction ratio of the light source; the signal processing module is also used to obtain the actual polarization extinction ratio of the light source according to the first detection data and the second detection data corresponding to a detection point; the actual polarization extinction ratio of the polarized light source is compared with the preset polarization extinction ratio of the light source; if the difference between the actual polarization extinction ratio of the polarized light source and the preset polarization extinction ratio of the light source is less than a preset threshold, then the final distance information corresponding to the detection point is output according to the detection data output by the main detector; the main detector is one of the first detector and the second detector that receives more beam energy when the detection surface does not have a polarization state change effect on the polarized light beam.

[0110] In an exemplary embodiment, the signal processing module is also used to output first distance information and second distance information according to the first detection data and the second detection data respectively when the difference between the actual polarization extinction ratio of the light source and the preset polarization extinction ratio of the light source is greater than a preset threshold; compare the actual polarization extinction ratio of the light source with the preset light source polarization information list table to determine the type of the detection surface; and select one of the first distance information and the second distance information as the final distance information of the detection point according to the type of the detection surface.

[0111] In an exemplary embodiment, a preset light source polarization information list table includes a plurality of sets of correspondences between detection surface types and selection rules; the signal processing module is also used to match the selection rules corresponding to the type of the detection surface in the preset light source polarization information list table according to the type of the detection surface; the selection rules include selecting closer distance information and selecting farther distance information; and selecting one of the first distance information and the second distance information as the final distance information according to the matched selection rules.

[0112] Each module in the above-mentioned laser radar detection device can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0113] In an exemplary embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as shown in FIG. Fig. 9As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, near field communication (NFC) or other technologies. When the computer program is executed by the processor, a laser radar detection method is implemented. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0114] Those skilled in the art will understand that Fig. 9 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0115] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0116] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0117] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0118] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0119] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0120] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A laser radar detection system, characterized in that: It includes a polarized light source, a reflected light deflector, a first polarization beam splitter, a scanning galvanometer, a first detector, a second detector and a processor; The polarized light source is used to emit a polarized light beam having a first polarization state, and the polarized light beam is sequentially passed through the reflected light deflector, the first polarization beam splitter and the scanning galvanometer and then projected onto the detection surface; The scanning galvanometer is used to project the incident polarized light beam to different detection points on the detection surface; The first polarization beam splitter is used to transmit the polarized light beam and to split the reflected light of the polarized light beam reflected by each detection point into a first polarization state reflected light emitted in a first direction and a second polarization state reflected light emitted in a second direction; The reflected light in the first polarization state is incident on the first detector after being changed in direction by the reflected light deflector; The first detector is used to receive the first polarization state reflected light and generate first detection data according to the first polarization state reflected light; The second detector is used to receive the second polarization state reflected light and generate second detection data according to the second polarization state reflected light; The processor is electrically connected to the first detector and the second detector, and is used to determine the difference between the detection signal value formed by the first detection data and the second detection data and the preset value of the light source, and generate a detection result for the detection surface according to the difference corresponding to each detection point in the detection surface.

2. The laser radar detection system according to claim 1, characterized in that: The polarization direction of the polarized light beam is consistent with the polarization direction of the first polarization beam splitter.

3. The laser radar detection system according to claim 2, characterized in that: The reflected light deflector comprises a non-polarizing circulator, and the non-polarizing circulator comprises a reflector, a beam splitter, a first birefringent crystal, a Faraday rotator, a first half-wave plate, and a second birefringent crystal; The first polarization state reflected light passes through the second birefringent crystal, the first half wave plate, the Faraday rotator and the first birefringent crystal in sequence and is projected onto the reflector and the beam splitter. The reflector is used to reflect the incident light to the beam splitter so that the beam splitter projects the incident first polarization state reflected light to the first detector.

4. The laser radar detection system according to claim 1, characterized in that: The reflected light deflector comprises a second polarization beam splitter and a second half-wave plate sequentially arranged along the outgoing light path of the polarized light beam; The second half wave plate is used to convert the first polarization state reflected light into the second polarization state reflected light; The second polarization beam splitter is used for transmitting the light in the first polarization state and reflecting the light in the second polarization state, so as to transmit the reflected light in the second polarization state to the first detector.

5. The laser radar detection system according to claim 1, characterized in that: It also includes a quarter wave plate, which is arranged on the light incident surface of the first polarization beam splitter for receiving the reflected light.

6. The laser radar detection system according to any one of claims 1 to 5, characterized in that: The laser radar further includes a first collimation component and a second collimation component; The first collimating component is arranged on the optical path between the polarized light source and the reflected light deflector, and is used to collimate the polarized light beam; The second collimating component is disposed on the optical path between the first polarization beam splitter and the second detector, and is used for collimating the reflected light of the second polarization state.

7. A laser radar detection method, characterized in that: It is implemented by the laser radar detection system according to any one of claims 1 to 6; the laser radar detection method comprises: Controlling the polarized light source to emit a polarized light beam having a first polarization state with a preset pulse; Determine the difference between the detection signal value corresponding to each detection point in the detection surface and the preset value of the light source, and generate the detection result of the detection surface according to the difference corresponding to each detection point; the detection signal value is formed by the first detection data of each detection point in the detection surface generated by the first detector based on the polarized light beam and the second detection data of each detection point in the detection surface generated by the second detector based on the polarized light beam.

8. The laser radar detection method according to claim 7, characterized in that: The detection result includes distance information of each detection point; the preset value of the light source is a preset polarization extinction ratio of the light source; judging the difference between the detection signal value corresponding to a detection point in the detection surface and the preset value of the light source, and generating the detection result of the detection surface according to the difference corresponding to the detection point, including: Acquire an actual polarization extinction ratio of a light source according to the first detection data and the second detection data corresponding to a detection point; Comparing the actual polarization extinction ratio of the light source with the preset polarization extinction ratio of the light source; If the difference between the actual polarization extinction ratio of the light source and the preset polarization extinction ratio of the light source is less than a preset threshold, the final distance information corresponding to the detection point is output according to the detection data output by the main detector; the main detector is one of the first detector and the second detector that receives more light beam energy when the detection surface has no polarization state change effect on the polarized light beam.

9. The laser radar detection method according to claim 8, characterized in that: The determining of the difference between a detection signal value corresponding to a detection point in the detection surface and a preset value of the light source, and generating a detection result for the detection surface according to the difference corresponding to the detection point, further includes: When the difference between the actual polarization extinction ratio of the light source and the preset polarization extinction ratio of the light source is greater than a preset threshold, outputting first distance information and second distance information according to the first detection data and the second detection data respectively; Comparing the actual polarization extinction ratio of the light source with a preset light source polarization information list table to determine the type of the detection surface; One of the first distance information and the second distance information is selected according to the type of the detection surface as the final distance information of the detection point.

10. The laser radar detection method according to claim 9, characterized in that: The preset light source polarization information list table includes a correspondence between multiple groups of detection surface types and selection rules; The selecting one of the first distance information and the second distance information as the final distance information according to the type of the detection surface includes: According to the type of the detection surface, a selection rule corresponding to the type of the detection surface is matched in the preset light source polarization information list; the selection rule includes selecting closer distance information and selecting farther distance information; One of the first distance information and the second distance information is selected as final distance information according to the matched selection rule.

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