Lidar

Abstract

The embodiment of the application relates to the technical field of laser detection, and discloses a laser radar. The laser radar comprises a shell module, a transceiving module, a scanning module and a calibration module. The transceiving module is accommodated in the shell module and is used for emitting detection light to detect a target object and receiving echo light, the echo light being formed by reflection of the detection light on the target object. The scanning module is accommodated in the shell module and comprises a scanning element, the scanning element can rotate relative to the shell module, and the scanning element is used for receiving the detection light and deflecting the detection light so that the detection light is emitted out of the laser radar. The calibration module is installed on the shell module and comprises a reflection part in a detection field of view of the laser radar, and the reflection part is used for reflecting the detection light emitted from the scanning element to form corresponding echo light. The laser radar can improve the status that, in the related art, when the scanning angle of the scanning element is recalibrated, the laser radar needs to rely on external calibration components and calibration scenes of the laser radar, and then the calibration process is complicated.

Description

Technical Field

[0001] This application relates to the field of laser detection technology, and more particularly to a lidar. Background Technology

[0002] LiDAR is a radar system that uses laser beams to detect the position, velocity, and other characteristics of a target. Its working principle is to first emit a detection light towards the target object, then receive the echo light reflected back from the target, and after appropriate processing, obtain relevant information about the target, such as the target's distance, azimuth, altitude, speed, attitude, and even shape.

[0003] Generally, a lidar system includes a housing, a transceiver module, and a scanning module. The housing serves as the mounting base for the remaining structures within the lidar system. The transceiver module emits probe light to detect target objects and receives the echo light reflected from the target objects. The scanning module includes a scanning element, such as a micro-electro-mechanical system (MEMS) galvanometer, that can rotate relative to the housing. This scanning element receives and deflects the probe light emitted by the transceiver module, thereby continuously changing the direction of the probe light to form a specific detection field of view, enabling the detection of target objects within the detection field of view. Correspondingly, the scanning element also receives and deflects the echo light so that it is directed towards the transceiver module. Summary of the Invention

[0004] In related technologies, lidar uses external calibration plates and other components to calibrate the scanning angle of the scanning element. For example, by placing the calibration plate at different angular positions within the lidar's detection field of view, the relationship between the feedback signal of the scanning element (e.g., feedback voltage signal) and the azimuth angle (e.g., horizontal azimuth or vertical elevation angle) of the calibration plate relative to the lidar can be calibrated. This allows for the mapping relationship between the scanning element's feedback signal and the detection light's azimuth angle (i.e., the scanning element's azimuth angle). However, as the operating time increases, the feedback sensitivity of the scanning element changes, meaning the amplitude of the feedback signal per unit rotation angle of the scanning element changes. If the lidar still determines the target object's azimuth angle based on the pre-calibrated mapping relationship, the measured azimuth angle will differ significantly from the actual azimuth angle of the target object, ultimately resulting in a decrease in the lidar's control accuracy during the scanning process within the detection field of view.

[0005] Taking vehicle-mounted LiDAR as an example, if the sensitivity of the LiDAR changes, the car needs to be driven to a preset calibration scene, or the LiDAR needs to be removed and placed in the aforementioned calibration scene to recalibrate the scanning angle position of the scanning element. This process relies on external calibration components and calibration scene, and the recalibration process of the scanning angle of the scanning element is cumbersome and costly.

[0006] This application aims to provide a lidar that improves upon the current situation in related technologies where lidar requires external calibration components and a specific calibration environment for recalibrating the scanning angle of the scanning element, resulting in a cumbersome calibration process.

[0007] The technical problem in this application is solved by the following solution:

[0008] This application provides a lidar, including a housing module, a transceiver module, a scanning module, and a calibration module. The transceiver module, housed in the housing module, is used to emit probe light to detect target objects and receive echo light, the echo light being formed by the reflection of the probe light from the target object. The scanning module, also housed in the housing module, includes a scanning element that is rotatable relative to the housing module. The scanning element receives and deflects the probe light so that it exits the lidar. The calibration module, mounted in the housing module, includes a reflective portion located within the lidar's detection field of view. The reflective portion reflects the probe light emitted from the scanning element to form corresponding echo light.

[0009] In some embodiments, the calibration module further includes a fixing part, which is fixed to the housing module. The fixing part includes a reference area located within the detection field of view of the lidar, and the reflective part is disposed in the reference area; wherein the reflectivity of the reference area is lower than a first threshold, the reflectivity of the reflective part is higher than a second threshold, and the second threshold is greater than the first threshold.

[0010] In some embodiments, the difference between the second threshold and the first threshold is greater than 50%.

[0011] In some embodiments, the reflective portion is disposed on the side of the fixing portion away from the scanning module, the fixing portion has a through hole extending from the side near the scanning module to the reflective portion, and the reflective portion blocks the through hole.

[0012] In some embodiments, the fixing part has a groove communicating with the through hole on the side opposite to the scanning module, and the reflective part is mounted in the groove.

[0013] In some embodiments, the bottom surface of the groove is configured such that the optical path of the probe light emitted from the scanning module toward the groove is perpendicular to the bottom surface.

[0014] In some embodiments, the reflective portion is a diffuse reflective film.

[0015] In some embodiments, the housing module includes a base shell and a lens. The base shell defines a receiving cavity and has a window communicating with the receiving cavity and the external environment. The lens includes a lens barrel and a lens element. The lens barrel is mounted at the window and has a mounting hole extending along a first preset direction. The lens element is mounted in the mounting hole, and the lens element blocks the window. The calibration module is mounted on the lens barrel.

[0016] In some embodiments, the mounting hole includes a first cavity and a second cavity arranged sequentially along the first preset direction. The first cavity is closer to the scanning module than the second cavity. When viewed along the first preset direction, the edge contour of the first cavity is located within the edge contour of the second cavity. The lens includes a first lens and a second lens. The first lens is mounted in the first cavity, and the second lens is mounted in the second cavity.

[0017] In some embodiments, the fixing part includes a first part and a second part. The first part is disposed on the bottom wall of the second cavity and projected along the first preset direction. The second part extends into the first cavity and includes the reference area.

[0018] In some embodiments, the reflective portion is disposed on the side of the fixing portion facing the scanning module, and the reflective portion includes a reflective material layer or a reflector disposed on the fixing portion.

[0019] In some embodiments, the reference area has a groove on the side facing the scanning module, and the reflective portion is disposed on the bottom surface of the groove; the bottom surface is configured such that the optical path of the probe light emitted from the scanning module to the groove is perpendicular to the bottom surface.

[0020] In some embodiments, the reference area has a boss on the side facing the scanning module, and the reflective portion is disposed on the top surface of the boss; the top surface is configured such that the optical path of the probe light emitted from the scanning module to the boss is perpendicular to the top surface.

[0021] In some embodiments, the reference area has an inclined surface on one side facing the scanning module that is tilted relative to the first preset direction, and the lidar satisfies at least one of the following conditions: the inclined surface has a groove, the reflective part is disposed on the bottom surface of the groove, and the inclined surface is configured such that the optical path of the probe light emitted from the scanning module to the groove is perpendicular to the inclined surface, and the bottom surface is parallel to the inclined surface; the inclined surface has a boss, the reflective part is disposed on the top surface of the boss, and the inclined surface is configured such that the optical path of the probe light emitted from the scanning module to the boss is perpendicular to the inclined surface, and the top surface is parallel to the inclined surface.

[0022] In some embodiments, the lidar includes two calibration modules, which are disposed on both sides of the axis of the lens along a second preset direction. The second preset direction is perpendicular to the first preset direction and the thickness direction of the lidar, respectively.

[0023] Compared to lidar in related technologies, the lidar provided in this application embodiment does not require external calibration components or separate calibration scenarios when the feedback sensitivity of the scanning element changes. Instead, it can determine the change in scanning angle caused by the change in the feedback sensitivity of the scanning element based on the built-in calibration module, thus simplifying the calibration process. In other words, the lidar provided in this application embodiment improves upon the cumbersome calibration process in related technologies where recalibrating the scanning angle of the scanning element requires external calibration components and scenarios. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 These are three-dimensional schematic diagrams of lidar provided in some embodiments of this application;

[0026] Figure 2 yes Figure 1 Exploded view of the lidar in China;

[0027] Figure 3 yes Figure 1 A 3D diagram of the center lens;

[0028] Figure 4 yes Figure 3 A cross-sectional view of the middle lens along line AA;

[0029] Figure 5 yes Figure 4 A 3D schematic diagram of the winning module;

[0030] Figure 6 This is a schematic diagram showing the concealed housing, transceiver module, and scanning module of a lidar according to another embodiment of this application;

[0031] Figure 7 yes Figure 6 A 3D schematic diagram of the winning module;

[0032] Figure 8 yes Figure 7 A magnified view of a portion at point B;

[0033] Figure 9 This is a schematic diagram showing the concealed housing, transceiver module, and scanning module of a lidar according to some embodiments of this application;

[0034] Figure 10 yes Figure 9 A magnified view of a portion of point C.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1. LiDAR;

[0037] 100. Housing module; 110. Base shell; 120. Lens; 111. Bottom shell; 112. Top shell; 1111. Bottom wall; 1112. First side wall; 1113. Second side wall; 1114. Third side wall; 1121. Top wall; 1122. Fourth side wall; 1123. Fifth side wall; 1124. Sixth side wall; 121. Lens barrel; 122. Lens; 1211. Mounting hole; 1212. First cavity; 1213. Second cavity; 1221. First lens; 1222. Second lens; 101. Receiving cavity; 102. Window;

[0038] 200. Transceiver module;

[0039] 300. Scanning module;

[0040] 400, Calibration module; 410, Fixing part; 420, Reflecting part; 411, First part; 412, Second part; 4111, Positioning hole; 4112, First recess; 4121, Reference area; 4122, Boss;

[0041] 1b, LiDAR; 400b, Calibration module; 410b, Fixing part; 420b, Reflecting part; 4121b, Reference area; 4123b, Groove; 4124b, Fixing surface; 4125b, Second sink;

[0042] 1c, LiDAR; 400c, Calibration module; 410c, Fixing part; 420c, Reflecting part; 4123c, Groove; 4126c, Through hole. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0044] In the following description, when referring to the accompanying drawings, the same numbers in different drawings denote the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0045] In related technologies, lidar uses external calibration plates and other components to calibrate the scanning angle of the scanning element. For example, by placing the calibration plate at different angular positions within the lidar's detection field of view, the relationship between the feedback signal of the scanning element (e.g., feedback voltage signal) and the azimuth angle (e.g., horizontal azimuth or vertical elevation angle) of the calibration plate relative to the lidar can be calibrated. This allows for the mapping relationship between the scanning element's feedback signal and the detection light's azimuth angle (i.e., the scanning element's azimuth angle). However, as the operating time increases, the feedback sensitivity of the scanning element changes, meaning the amplitude of the feedback signal per unit rotation angle of the scanning element changes. If the lidar still determines the target object's azimuth angle based on the pre-calibrated mapping relationship, the measured azimuth angle will differ significantly from the actual azimuth angle of the target object, ultimately resulting in a decrease in the lidar's control accuracy during the scanning process within the detection field of view.

[0046] Taking vehicle-mounted LiDAR as an example, if the sensitivity of the LiDAR changes, the car needs to be driven to a preset calibration scene, or the LiDAR needs to be removed and placed in the aforementioned calibration scene to recalibrate the scanning angle position of the scanning element. This process relies on external calibration components and calibration scene, and the recalibration process of the scanning angle of the scanning element is cumbersome and costly.

[0047] Based on this, this application provides a lidar to improve the current situation in related technologies where lidars need to rely on external calibration components and calibration scenarios when recalibrating the scanning angle of the scanning element, resulting in a cumbersome calibration process.

[0048] Please see Figure 1 and Figure 2The diagrams show a perspective view and an exploded view of a lidar 1 provided in some embodiments of this application. The lidar 1 includes a housing module 100, a transceiver module 200, a scanning module 300, and a calibration module. The transceiver module 200 is housed in the housing module 100 and is used to emit probe light to detect target objects and receive echo light; wherein the echo light is formed by the reflection of the probe light from the target object. The scanning module 300 is housed in the housing module 100 and includes a scanning element that can rotate relative to the housing module 100; the scanning element is used to receive and deflect the probe light so that the probe light exits beyond the lidar 1. The calibration module is mounted on the housing module 100 and includes a reflective portion located in the detection field of view of the lidar 1, which reflects the probe light emitted from the scanning element to form a corresponding echo light.

[0049] It should be noted that, in this application, "target object" refers to the object detected by the lidar, including but not limited to: vehicles, pedestrians, buildings, vegetation, and the ground; "detection light" refers to the laser beam emitted by the lidar for detecting the aforementioned target object; and "echo light" refers to the laser beam reflected by the target object and directed towards the lidar. The target object can be an object other than the lidar, such as the aforementioned vehicles and pedestrians, or it can be the calibration module integrated into the lidar 1. The specific structure of the lidar 1 will now be described in detail with reference to the accompanying drawings.

[0050] For the aforementioned housing module 100, please refer to [the relevant documentation]. Figure 1 and Figure 2 It serves as the mounting base for the other components in the lidar 1, and also constitutes a protective structure for the other components in the lidar 1. In this embodiment, the housing module 100 includes a base shell 110 and a lens 120. The base shell 110 is the main body of the housing module 100, defining a receiving cavity 101 for housing the transceiver module 200 and the scanning module 300. The base shell 110 also has a window 102 connecting the receiving cavity 101 and the external environment of the lidar 1, allowing the detection light and echo light to enter and exit the lidar 1. The lens 120 is located at the window 102, and is used to perform optical processing on the detection light and echo light. At the same time, the lens 120 blocks the window 102, thereby achieving the sealing of the base shell 110.

[0051] For more information on the aforementioned base shell 110, please refer to [link / reference needed]. Figure 2The base shell 110 includes a bottom shell 111 and a top shell 112. The bottom shell 111 and the top shell 112 are joined and fixed along the thickness direction Z of the lidar 1 to define the aforementioned receiving cavity 101. The "thickness direction" as described in this application refers to the direction determined based on the bottom and top when the lidar 1 is installed on a mobile device (such as a car), where the end closer to the mounting surface of the mobile device is the bottom, and the end away from the mounting surface is the top. The thickness direction is determined by the direction between the bottom and the top, such as the direction between the bottom and the top pointing towards the other. The bottom shell 111 includes a bottom wall 1111, a first side wall 1112, a second side wall 1113, and a third side wall 1114. The bottom wall 1111 is generally a flat plate-like structure, along a first predetermined direction X as shown in the figure. The first side wall 1112 is located at one end of the bottom wall 1111. The first predetermined direction X is perpendicular to the aforementioned thickness direction Z. One end of the second sidewall 1113 is connected to the first sidewall 1112, and the other end extends away from the first sidewall 1112 along a first preset direction X. The height of the first sidewall 1112 relative to the bottom wall 1111 decreases as it moves further away from the first sidewall 1112. One end of the third sidewall 1114 is connected to the first sidewall 1112, and the other end also extends away from the first sidewall 1112 along a first preset direction X. The height of the first sidewall 1112 relative to the bottom wall 1111 decreases as it moves further away from the first sidewall 1112. The third sidewall 1114 and the second sidewall 1113 are arranged opposite each other along a second preset direction Y as shown in the figure. The second preset direction Y is perpendicular to both the thickness direction Z and the first preset direction X. The bottom shell 111 does not have a sidewall on the side away from the first sidewall 1112, thus forming an opening on that side to facilitate the assembly of components such as the transceiver module 200, the scanning module 300, and the circuit board.

[0052] The top shell 112 includes a top wall 1121, a fourth side wall 1122, a fifth side wall 1123, and a sixth side wall 1124. The top wall 1121 is also generally flat and plate-like, and is positioned opposite the bottom wall 1111 along the thickness direction Z. Along the first predetermined direction X, the fourth side wall 1122 is located at the end of the top wall 1121 opposite to the first side wall 1112, and is positioned opposite to the first side wall 1112 along the first predetermined direction X. The fourth side wall 1122 fills the open area of ​​the bottom shell 111 to seal the area. One end of the fifth side wall 1123 is connected to the fourth side wall 1122, and the other end extends away from the fourth side wall 1122 along the first predetermined direction X. The height of the fifth side wall 1123 relative to the top wall 1121 decreases as it moves further away from the fourth side wall 1122. The fifth sidewall 1123 and the second sidewall 1113 are complementary and adaptable structures. The fifth sidewall 1123 and the second sidewall 1113 are jointly spliced ​​to form a sidewall of the base shell 110 located between the first sidewall 1112 and the fourth sidewall 1122. One end of the sixth sidewall 1124 is connected to the fourth sidewall 1122, and the other end also extends away from the fourth sidewall 1122 along the first preset direction X. The height of the sixth sidewall 1124 relative to the top wall 1121 decreases as it moves further away from the fourth sidewall 1122. The sixth sidewall 1124 and the fifth sidewall 1123 are arranged opposite each other along the second preset direction Y shown in the figure. The sixth sidewall 1124 and the third sidewall 1114 are complementary and adaptable structures. The sixth sidewall 1124 and the third sidewall 1114 are jointly spliced ​​to form another sidewall of the base shell 110 located between the first sidewall 1112 and the fourth sidewall 1122. The top shell 112 does not have a sidewall on the side opposite to the fourth sidewall 1122, thus forming an opening on that side; the aforementioned first sidewall 1112 fills the opening to seal it. It should be noted that the "second preset direction" described in this application is perpendicular to the aforementioned first preset direction X; for example, in this embodiment, the second preset direction Y is a horizontal direction perpendicular to the first preset direction. Of course, in other embodiments, the second preset direction Y can also be appropriately varied based on this, and this application does not limit this.

[0053] The bottom shell 111 and the top shell 112 are joined together along the thickness direction Z shown in the figure to jointly define the aforementioned receiving cavity 101. The bottom shell 111 has the aforementioned window 102 on the first side wall 1112, which penetrates the first side wall 1112 and thus connects the aforementioned receiving cavity 101 with the external environment of the lidar 1.

[0054] Regarding the aforementioned lens 120, please refer to Figure 3 and Figure 4The diagram shows a three-dimensional schematic diagram of lens 120 and a cross-sectional schematic diagram along line AA. Lens 120 includes a lens barrel 121 and a lens 122. Lens barrel 121 is mounted at the window 102, and is spaced apart from the scanning module 300 along the first preset direction X, and has a mounting hole 1211 extending along the first preset direction X. Lens 122 is mounted in mounting hole 1211. Lens 120 completely seals the window 102, so that the housing module 100 forms an externally sealed structure. In this embodiment, the mounting hole 1211 includes a first cavity 1212 and a second cavity 1213 arranged sequentially along the first preset direction X. The first cavity 1212 is a cavity near the receiving cavity 101, one end of which is located in and communicates with the receiving cavity 101, and the other end extends toward or through the window 102. The second cavity 1213 is a cavity located away from the receiving cavity 101. One end of it is connected to the first cavity 1212, and the other end is located outside the base shell 110. When viewed along the first preset direction X, the edge contour of the first cavity 1212 is located within the edge contour of the second cavity 1213, meaning the second cavity 1213 is a larger cavity. The lens 120 includes two lenses 122, namely a first lens 1221 and a second lens 1222. The first lens 1221 is mounted in the first cavity 1212, and the second lens 1222 is mounted in the second cavity 1213. The detection light generated by the transceiver module 200 is deflected by the scanning module and then passes sequentially through the first lens 1221 and the second lens 1222 before being emitted outside the lidar 1 to detect the surrounding environment. That is, the second lens 1222 also constitutes a window of the lidar 1.

[0055] For details regarding the aforementioned transceiver module 200, please refer to [link / reference needed]. Figure 2The transceiver module 200 is housed within the receiving cavity 101 and mounted on the housing module 100. For example, the transceiver module 200 can be fixed to the bottom wall 1111. The transceiver module 200 includes a transmitting module and a receiving module. The transmitting module generates a detection light for detecting a target object. The transmitting module includes at least one laser. For example, in some embodiments, the transmitting module includes one laser; in other embodiments, the transmitting module includes two or more lasers arranged according to a preset rule. The receiving module receives the echo light formed by the detection light reflected from the target object and performs photoelectric conversion to obtain a corresponding electrical signal. This allows the signal processing module of the lidar 1 to obtain information such as the distance, speed, and reflectivity of the target object relative to the lidar 1 based on the aforementioned electrical signal processing. In some embodiments, the receiving module may include a silicon photomultiplier tube, which has a high dynamic range and can detect relatively weak echo light signals. Of course, in other embodiments of this application, the receiving module may also include other types of photodetectors, as long as they can receive the echo light and perform photoelectric conversion.

[0056] For the aforementioned scanning module 300, please refer to [link / reference needed]. Figure 2 The scanning module 300 is used to scan the probe light emitted from the transceiver module 200 so that the probe light can form a specific detection field of view. In this embodiment, the scanning module 300 includes a scanning element (not shown in the figure), which is used to receive and deflect the probe light so that the probe light is emitted outside the lidar. The scanning element can rotate relative to the housing module 100, so that the emission direction of the probe light changes continuously after being reflected by it, thereby realizing the above-mentioned detection field of view. Optionally, the scanning element may include a two-dimensional galvanometer, such as a two-dimensional MEMS (Micro-Electro-Mechanical System) galvanometer, to achieve two-dimensional scanning. Of course, in other embodiments of this application, the scanning element may also include other types of scanning devices; for example, in some other embodiments, the scanning element may be a combination of a one-dimensional galvanometer and a multi-faceted rotating mirror; for example, in some other embodiments, the transmitting module may include a linear array of multiple lasers, and the scanning element includes a one-dimensional rotating mirror; it is not limited here, as long as the scanning module 300 can complete the scanning of the probe light, preferably, the above-mentioned two-dimensional scanning scheme can be adopted. In addition, the scanning module 300 also includes a scanning drive module, which is connected to the scanning element and is used to drive the scanning element to rotate. In this embodiment, the drive module includes a coil and a magnet. Specifically, the coil is integrated into the two-dimensional galvanometer; the magnet is disposed adjacent to the two-dimensional galvanometer, and the two-dimensional galvanometer is in the magnetic field formed by the magnet; when the coil is energized according to a preset pattern, it will rotate under the action of the magnetic field.

[0057] To obtain the current scanning direction angle of the 2D galvanometer, the galvanometer can integrate a sensor for detecting the direction angle, such as a piezoresistive sensor. Since the feedback voltage signal output by the piezoresistive sensor varies depending on the scanning direction angle of the 2D galvanometer, a mapping relationship between the two can be established through the calibration process described above. Thus, during the operation of the lidar after it leaves the factory, the current scanning direction angle of the 2D galvanometer can be determined by the feedback voltage signal output by the piezoresistive sensor.

[0058] However, as the operating time increases, the feedback sensitivity of the scanning element changes, meaning the amplitude of the feedback signal (such as the aforementioned feedback voltage signal) under a unit rotation angle condition of the scanning element changes. If the lidar still determines the direction angle corresponding to the target object based on the mapping relationship calibrated before leaving the factory, the measured direction angle will differ significantly from the actual direction angle of the target object, ultimately resulting in a decrease in the control accuracy of the lidar during the scanning process within the detection field of view. To overcome this deficiency, the lidar 1 provided in this application embodiment also includes a calibration module 400. The calibration module 400 provides the structural basis for the secondary calibration of the scanning element, thereby helping to improve the cumbersome secondary calibration process of lidar in related technologies.

[0059] For calibration module 400, please refer to the following document. Figure 5 It shows a three-dimensional schematic diagram of the calibration module 400, and in conjunction with Figures 1 to 4 The calibration module 400 is mounted on the housing module 100 and includes a reflector 420 located in the detection field of view of the lidar 1. The reflector 420 reflects the detection light reflected by the scanning module 300 and directed towards it, forming a corresponding echo light so that the lidar 1 can determine the angular position of the reflector 420 in the detection field of view. Considering that the lens 120 is actually designed and selected based on the detection field of view requirements of the lidar 1, in this embodiment, the calibration module 400 is mounted on the lens 120. This arrangement can easily ensure that the reflector 420 is located in the detection field of view of the lidar 1. This arrangement will be used as an example for the following description; however, it should be understood that in other embodiments of this application, the calibration module 400 can also be mounted on the base housing 110, as long as it has the aforementioned reflector located in the detection field of view of the lidar 1.

[0060] Specifically, the calibration module 400 includes a fixing part 410 and the aforementioned reflecting part 420. The fixing part 410 is mounted on the bottom wall of the second cavity 1213, and includes a first portion 411 located on the bottom wall of the second cavity 1213 and a second portion 412 located outside the bottom wall of the second cavity 1213. One end of the second portion 412 is connected to the first portion 411, and the other end extends to be opposite to the first cavity 1212. More specifically, when the fixing part 410 projects along the first preset direction X, the first portion 411 is located on the bottom wall of the second cavity 1213, and the end of the second portion 412 facing away from the first portion 411 is located in the first cavity 1212. The second portion 412 includes a reference area 4121 located within the detection field of view of the lidar 1. This reference area 4121 is used to set the aforementioned reflecting part 420, thereby effectively ensuring that the reflecting part 420 is also located within the detection field of view of the lidar 1.

[0061] The fixing method of the fixing part 410 is actually diverse. For example, in some embodiments, the fixing part 410 and the lens barrel 121 can be bonded together. Specifically, the first part 411 is a roughly rectangular plate structure with multiple positioning holes 4111; the bottom wall of the second cavity 1213 is provided with multiple positioning posts (not shown in the figure), each positioning post extending into a corresponding positioning hole 4111, thereby realizing the positioning of the fixing part 410 and the lens barrel 121. Preferably, two positioning holes 4111 and two positioning posts can be provided respectively, one positioning hole 4111 being a circular hole and the other positioning hole 4111 being an oblong hole; wherein, the width of the oblong hole is equal to the diameter of the positioning post, and the length of the oblong hole is greater than the diameter of the positioning post. One positioning post mates with the circular positioning hole 4111, and the other positioning post mates with the oblong positioning hole 4111. The oblong hole provides a certain redundancy to avoid it not mates properly with the corresponding positioning post. The first part 411 has a first recess 4112 on the side facing the bottom wall of the second cavity 1213. The first recess 4112 can be used to hold adhesive. Before the fixing part 410 is assembled to the lens barrel 121, adhesive can be applied to the first recess 4112. Then, the fixing part 410 is positioned and installed on the bottom wall of the second cavity 1213 based on the positioning hole 4111 and the positioning post. After that, the position and orientation of the fixing part 410 are adjusted to the desired state, and the fixing part 410 is fixed after the adhesive cures.

[0062] Preferably, the reflectivity of the reference region 4121 is lower than that of the reflector. For example, the reflectivity of the reference region 4121 is lower than a first threshold, while the reflectivity of the reflector is higher than a second threshold, which is higher than the first threshold, so that the reflectivity of the reflector 420 is higher than that of the reference region 4121. This arrangement helps to construct a low-reflectivity reference region 4121 in the neighborhood of the reflector 420. The reference region 4121 can block other target objects in the field of view, preventing other target objects in the field of view from affecting the detection of the reflector 420, thus creating a relatively pure detection environment for the reflector 420. The reflector 420, as an object with higher reflectivity, is located in this region and has a reflectivity difference from the reference region 4121. In this way, the lidar 1 can more easily identify the reflector 420 when acquiring point cloud data. Optionally, the difference between the second threshold and the first threshold is greater than 50%; thus, the reflective portion 420 and the reference area 4121 of the fixed portion 410 will have a significant difference in reflectivity, which is beneficial for better distinguishing the outline of the reflective portion 420. For example, in some embodiments, the first threshold may be less than 30%, such as 25%, 20%, 10%, 5%, etc.; the second threshold may be greater than 80%, such as 85%, 90%, 92%, 95%, etc. It should be noted that the "reflectivity" mentioned in this application refers to a parameter commonly used in the field of lidar detection to characterize reflectivity. Generally, the surface reflectivity of a Kodak whiteboard (calibration whiteboard) is defined as 100%, and the reflectivity of other objects can be obtained by proportional conversion based on it.

[0063] As for the structure of the reflective part 420, it is actually diverse. It can be a reflective material layer, such as a reflective coating, provided in the reference area 4121, or a reflective mirror, such as a silver mirror or an aluminum mirror, provided in the reference area 4121, or a reflective film, such as a high-reflective film used in road traffic, provided in the reference area. This application does not specifically limit the specific structure of the reflective part 420, as long as it is located in the detection field of the lidar 1 and has the function of reflecting detection light. The reflective part 420 provided in some embodiments of this application will be described below with reference to the accompanying drawings.

[0064] In some embodiments, the reflective portion 420 includes a reflective material layer disposed on the reference region 4121. For example, the reflective material layer may be a high-reflectivity material layer formed on the surface of the reference region 4121 by spraying, electroplating, or other processes; wherein, the high-reflectivity material layer may include a titanium reflective film, or a silicon reflective film, or a reflective film based on titanium and silicon. Thus, when the probe light is emitted from the scanning module 300 to the reflective portion 420, an echo light will be formed due to the reflection of the reflective portion 420, and the echo light will be further received by the transceiver module of the lidar.

[0065] It is important to note that when the reflective material layer forms a reflective mirror, the reflection direction of the emitting material layer can be considered singular, unlike diffuse reflection which generates reflected echoes in all directions. In this case, the angle of the plane containing the reflective material layer is crucial. Specifically, the reflective material layer needs to be configured such that the optical path of the probe light emitted by the self-scanning module 300 towards the reflective material layer is perpendicular to the reflective material layer. In this way, the echo light formed by the reflection of the reflective material layer can return along the original optical path and be received by the transceiver module 200, thereby forming the corresponding point cloud.

[0066] For example, please continue reading Figure 5 In some applications, the reference area 4121 has a protrusion 4122 on the side facing the scanning module 300, and a reflective material layer is disposed on the top surface of the protrusion 4122. This top surface is configured such that the probe light emitted from the scanning module 300 towards the protrusion 4122 is perpendicular to the top surface of the protrusion 4122; thus, the probe light will be perpendicularly incident on the reflective material layer and return to the transceiver module 200 along the original optical path. In other applications, the reference area 4121 has a groove (not shown in the figure) on the side facing the scanning module 300, and a reflective material layer is disposed on the bottom surface of the groove; this bottom surface is configured such that the optical path of the probe light emitted from the scanning module 300 towards the groove is perpendicular to the bottom surface; thus, the probe light will also be perpendicularly incident on the reflective material layer and return to the transceiver module 200 along the original optical path. Preferably, in order to facilitate a better reference surface when forming the top surface of the boss 4122 or the bottom surface of the groove, the reference area 4121 is provided with an inclined surface on the side facing the scanning module 300, which is inclined relative to the first preset direction X. The inclined surface is configured such that the light path of the probe light emitted from the scanning module 300 to the boss or groove is perpendicular to the inclined surface. Then, when forming the top surface of the boss 4122 or the bottom surface of the groove, it is only necessary to control the top surface of the boss 4122 or the bottom surface of the groove to be parallel to the inclined surface.

[0067] In other embodiments, the reflective portion 420 may not be an integrally formed adhesion material layer on the surface of the reference region 4121, but rather a separate component relative to the reference region 4121, and fixed to the reference region 4121 by means of adhesive or the like. For example, please refer to... Figures 6 to 8 The diagrams show the concealed housing, transceiver module, and scanning module of the lidar 1b according to another embodiment of this application. Figure 6 A schematic diagram of the 400b module and its specifications. Figure 7The enlarged schematic diagram at point B shows that the lidar 1b is basically the same as the lidar 1 in the above embodiment, with the main difference being that the calibration module 400b in lidar 1b is different from the calibration module 400 in the above embodiment; the reflective part 420b in the calibration module 400b is a reflector. Specifically, the fixing part 410b includes a reference area 4121b located within the detection field of view of lidar 1b, and the reference area 4121b is provided with a groove 4123b; the reflective part 420b includes a reflector, which is installed in the groove 4123b. Optionally, a fixing surface 4124b is provided inside the groove 4123b, which is inclined relative to the first preset direction X, and configured such that the optical path of the detection light emitted by the self-scanning module 300 towards the groove 4123b is perpendicular to the fixing surface 4124b; the reflector is installed on the fixing surface 4124b. Thus, when the probe light is incident on the reflector, the resulting echo light will return along the optical path and be received by the transceiver module 200. In this embodiment, the reflector is fixed in the groove 4123b by adhesive application. Specifically, the fixing part 410b has a second recess 4125b on the fixing surface 4124b, which divides the fixing surface 4124b into multiple regions; for example, the fixing surface 4124b may have two second recesses 4125b, which intersect perpendicularly, thereby dividing the fixing surface 4124b into four regions. The reflector is supported in the multiple regions and fixed to the fixing part by adhesive. When fixing the reflector, adhesive can be applied to its back side (the side facing the fixing surface 4124b), and the reflector can be placed in the correct position on the fixing surface 4124b, and the adhesive can be allowed to cure; the second recess 4125b can be used to accommodate excess adhesive and prevent overflow.

[0068] It should be understood that although the above description uses the example of a groove 4123b provided in the reference area 4121b and a reflector placed in the groove 4123b, this application is not limited to this. As long as the reflector is fixed to the reference area 413b and perpendicular to the light path of the probe light directed thereto, it is acceptable. For example, in some other embodiments of this application, the fixing part 410 can also be as follows: Figures 3 to 5 The embodiment shown has a boss to which the reflector is fixed.

[0069] It is worth mentioning that although the above embodiments are described with the reflective part located on the side of the fixed part facing the scanning module as an example, it should be understood that this application is not limited to this. As long as the reflective part is installed on the fixed part and can reflect the probe light to form an echo light directed towards the scanning module, it is acceptable.

[0070] For example, please see Figures 9 to 10These illustrations show schematic diagrams of the concealed housing, transceiver module, and scanning module of the LiDAR 1c provided in other embodiments of this application, respectively. Figure 9 The enlarged view at point C shows that the lidar 1c in this embodiment is largely the same as the lidar 1 in the above embodiment, with the main difference being that the calibration module 400c in lidar 1c is different from the calibration module 400 in the above embodiment; the reflective part 420c of the calibration module 400c is located on the side of the fixing part 410c away from the scanning module, and the fixing part 410c of the calibration module 400c is provided with a through hole extending from the side near the scanning module to the reflective part 420c, and the reflective part 420c blocks the through hole.

[0071] Specifically, one end of the fixing part 410c is connected to the inner wall of the mounting hole, and the other end extends toward the axis of the mounting hole. A groove 4123c is provided on the surface of the fixing part 410c facing away from the scanning module, and the reflecting part 420c is installed in this groove 4123c; for example, the reflecting part 420c can be fixed in the groove 4123c by any fixing method such as adhesive or snap-fit. The fixing part 410c also has a through hole 4126c, one end of which penetrates the surface of the fixing part 410c facing the scanning module, and the other end extends to communicate with the aforementioned groove 4123c; the through hole 4126c is used for the passage of the detection light and echo light corresponding to the reflecting part 420c. Optionally, the extending direction of the through-hole 4126c can be configured to be consistent with the optical path of the probe light directed towards the reflector 420c, thereby ensuring that the probe light can smoothly reach the reflector 420c. Of course, in other embodiments, the through-hole 4126c can also be set to a larger diameter to provide greater tolerance and ensure that the probe light can reach the reflector 420c. In this embodiment, the reflector 420c includes a diffuse reflective film, which can be fixed in the groove 4123c by adhesive bonding. For example, the diffuse reflective film can be a diamond-grade diffuse reflective film or a reflective film used in road traffic. Using a diffuse reflective film as the reflector 420 ensures that regardless of the incident angle of the probe light, an echo light will be generated that travels towards the scanning module 300. Therefore, it is not necessary to specially set the angle and orientation of the reflector 420 as in the above embodiments. That is, this setting allows for greater freedom and higher tolerance in the design and manufacturing of the shape and orientation of the fixing part 410 and the reflector 420. Of course, in other embodiments of this application, the reflector 420 can also use a specular reflection type reflective medium, such as a mirror (e.g., a silver mirror or an aluminum mirror). In this case, similar to the previous embodiments, the bottom surface of the groove 4123c of the fixing part needs to be configured perpendicular to the optical path of the probe light from the self-scanning module that travels towards the groove.

[0072] It is worth noting that since the calibration module 400 is used to calibrate the scanning direction angle of the scanning element, it is necessary to ensure that the position and orientation of the calibration module 400 remain essentially unchanged during the service life of the lidar 1. In this embodiment, if the fixing part and the lens barrel are separately formed, the strength of the fixing part itself should be higher than a preset strength threshold, and the stiffness should be higher than a preset stiffness threshold. These preset strength thresholds and preset stiffness thresholds can be determined by testing or simulation based on the operating conditions of the lidar 1. For example, the fixing part can be formed using the same material as the lens barrel. In addition, when the fixing part is fixed to the lens barrel, rigid glue can be used to ensure the reliability of the connection, or threaded fasteners can be used for fixing. If the fixing part and the lens barrel are integrally formed, the strength of the fixing part itself can generally be better guaranteed. Of course, the material of the lens barrel can also be appropriately selected to improve the reliability of the fixing part's structural form. Regarding the arrangement of the reflective part, if the reflective part is a reflective material layer molded on the surface of the fixed part, its position and orientation relative to the fixed part are relatively stable, and it is only necessary to ensure that the position and orientation of the fixed part has good durability; if the reflective part is a reflector / diffuse reflective film that is separately molded relative to the fixed part and fixed to the fixed part, then rigid adhesive should be used to avoid changes in the position and orientation of the reflective part due to adhesive failure.

[0073] The structures of the housing module 100, transceiver module 200, scanning module 300 and calibration module 400 have been described above. Next, the working principle of the lidar 1 being calibrated based on the calibration module 400 will be briefly explained.

[0074] When the lidar is calibrated at the factory, the directional angle corresponding to the reflector 420 can be obtained by scanning; for ease of explanation, this directional angle is referred to as the first preset directional angle. When the lidar has been used for a long time and the feedback sensitivity of the scanning element changes, the directional angle corresponding to the reflector 420 can be obtained by scanning; for ease of explanation, this directional angle is referred to as the second preset directional angle. Thus, based on the first preset directional angle and the second preset directional angle, the proportion of the change in the feedback sensitivity of the scanning element can be determined, and then the directional angle determined based on the feedback signal can be compensated based on this proportion to obtain a corrected directional angle.

[0075] Considering that the scanning direction angle of the scanning element is determined by the feedback signal output by the sensor (such as a piezoresistive sensor) integrated into the scanning element, and since the sensitivity of the sensor may vary at different locations, the change in feedback sensitivity of the scanning element on both sides of the center angle position in the second preset direction may not be consistent. To further improve this deficiency, in this embodiment, the lidar 1 includes two calibration modules 400, which are respectively disposed on both sides of the axis of the lens 120 along the second preset direction Y.

[0076] Based on this, in some applications, the change ratio of the feedback sensitivity on one side can be determined by the calibration module 400 located on one side of the optical axis of lens 120, thereby determining the first compensation coefficient corresponding to that side. Similarly, the change ratio of the feedback sensitivity on the other side can be determined by the calibration module 400 located on the other side of the optical axis of lens 120, thereby determining the second compensation coefficient corresponding to that side. Then, based on the first and second compensation coefficients, azimuth compensation is performed on point cloud points whose azimuth angles are on the same side in the point cloud data. This application method allows for different compensation methods to be used on two specific azimuth sides when the scanning element scans in the second preset direction, which helps to improve the accuracy of the compensation process to a certain extent. In other applications, the first included angle between the reflectors 420 of the two calibration modules 400 in the detection field of view of the lidar 1 can be determined at the time of manufacture. This first included angle can be determined based on the azimuth angles corresponding to the reflectors 420 of one calibration module 400 and the azimuth angles corresponding to the reflectors 420 of the other calibration module 400 at the time of manufacture of the lidar 1; for example... Figure 4 The azimuth angle corresponding to the reflector 420 of the calibration module 400 on the right (corresponding to the left side of the field of view of LiDAR 1) is -55°, and the azimuth angle corresponding to the reflector 420 of the calibration module 400 on the left (corresponding to the right side of the field of view of LiDAR 1) is 55°. Therefore, the first included angle is 110°. Then, the second included angle corresponding to the two calibration modules 400 in the detection field of view of LiDAR 1 is determined. This second included angle can be determined based on the azimuth angle corresponding to the reflector 420 of one calibration module 400 and the azimuth angle corresponding to the reflector 420 of the other calibration module 400; for example... Figure 4 The azimuth angle corresponding to the reflective part of the calibration module on the right (corresponding to the left side of the field of view of LiDAR 1) is -57°, and the azimuth angle corresponding to the reflective part of the calibration module on the left (corresponding to the right side of the field of view of LiDAR 1) is 58°. Therefore, the second preset azimuth angle is 115°. Then, the compensation coefficient is determined based on the second included angle and the first included angle; specifically, the ratio of the first included angle to the second included angle can be determined as the compensation coefficient; for example, based on the above example, the compensation coefficient α can be determined as 110° / 115° = 0.9565. Afterwards, when LiDAR 1 detects and acquires point cloud data, the azimuth angle of the point cloud points in the point cloud data is multiplied by the above compensation coefficient. This application method uses the included angle between the two calibration modules 400 to determine the compensation coefficient, which can balance the unilateral error introduced by a single calibration module 400 when detecting its azimuth angle, which is beneficial to improving the accuracy of the compensation process.

[0077] In summary, the lidar 1 provided in this application embodiment includes a housing module 100, a transceiver module 200, a scanning module 300, and a calibration module 400. The calibration module 400 includes a reflective portion located in the detection field of view of the lidar 1.

[0078] In related technologies, when the feedback sensitivity of the scanning element of a lidar changes, it needs to be placed in a preset calibration scenario. This requires a calibration element outside the lidar itself and another lidar (such as a true-value lidar with accurate azimuth angles) to perform secondary calibration of the scanning direction angle. In contrast, the lidar 1 (1b, 1c) provided in this application embodiment does not require a calibration element outside the lidar 1, nor does it require a separate calibration scenario for the lidar 1. Instead, it can determine the change in scanning angle caused by the change in the feedback sensitivity of the scanning element based on the built-in calibration module 400, thus simplifying the calibration process. In other words, the lidar 1 provided in this application embodiment can improve the current situation in related technologies where lidars require external calibration components and calibration scenarios when recalibrating the scanning angle of the scanning element, leading to a cumbersome calibration process.

[0079] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" means at least two, for example, two, three, four, etc. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0080] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A lidar, comprising: The application relates to a laser radar, comprising: a housing module; a transceiver module accommodated in the housing module, used for emitting probe light to detect a target object and receiving echo light formed by the probe light reflected by the target object; a scanning module accommodated in the housing module, comprising a scanning element, the scanning element being capable of rotating relative to the housing module, the scanning element being used for receiving the probe light and deflecting the probe light so that the probe light is emitted out of the laser radar; and a calibration module mounted on the housing module, comprising a reflecting part located in a detection field of view of the laser radar, the reflecting part being used for reflecting the probe light emitted from the scanning element to form corresponding echo light; the calibration module further comprises a fixing part fixed to the housing module, the fixing part comprising a reference area located in the detection field of view, the reflecting part being arranged in the reference area, the reference area being configured to shield other target objects in a field of view area corresponding to the reference area, the reflectivity of the reference area being lower than a first threshold value, the reflectivity of the reflecting part being higher than a second threshold value, the second threshold value being greater than the first threshold value; the reflecting part is arranged on a side of the fixing part away from the scanning module, the fixing part is provided with a through hole extending from a side close to the scanning module to the reflecting part, and the reflecting part blocks the through hole; the laser radar is configured to determine a proportion of a change in feedback sensitivity of the scanning element based on a first preset direction angle and a second preset direction angle, to compensate for a direction angle determined according to a feedback signal of the scanning element based on the proportion, and to obtain a corrected direction angle, wherein the first preset direction angle is a direction angle obtained by scanning the reflecting part when the laser radar is completed and calibrated, and the second preset direction angle is a direction angle obtained by the laser radar by scanning the reflecting part when the feedback sensitivity of the scanning element changes.

2. The lidar of claim 1, wherein, The difference between the second threshold value and the first threshold value is greater than 50%.

3. The lidar of claim 1, wherein, The side of the fixing part away from the scanning module is provided with a groove in communication with the through hole, and the reflecting part is mounted in the groove.

4. The lidar of claim 3, wherein, The bottom surface of the groove is configured so that the light path of the probe light emitted from the scanning module to the groove is perpendicular to the bottom surface.

5. The lidar of claim 2, wherein, The reflecting part is a diffuse reflection film.

6. The lidar of claim 1, wherein, The housing module comprises: a base shell defining an accommodation cavity and provided with a window in communication with the accommodation cavity and an external environment; and a lens comprising a lens barrel and a lens, the lens barrel being mounted at the window and provided with a mounting hole extending along a first preset direction, the lens being mounted in the mounting hole, and the lens blocking the window; the calibration module is mounted on the lens barrel.

7. The lidar of claim 6, wherein, The mounting hole comprises a first cavity and a second cavity arranged in sequence along the first preset direction, the first cavity being closer to the scanning module than the second cavity, and the edge profile of the first cavity being located within the edge profile of the second cavity when viewed along the first preset direction; the lens comprises a first lens and a second lens, the first lens being mounted in the first cavity, and the second lens being mounted in the second cavity.

8. The lidar of claim 7, wherein, The fixing part comprises a first part and a second part, the first part is arranged on the bottom wall of the second cavity and projects along the first preset direction, and the second part extends into the first cavity, and the second part comprises the reference area.

9. The lidar of any one of claims 6-8, wherein, The laser radar comprises two calibration modules, and the two calibration modules are arranged on two sides of the axis of the lens along a second preset direction, and the second preset direction is perpendicular to the first preset direction and the thickness direction of the laser radar.

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