LiDAR and Detection Method for Simultaneous Exposure and Point Laser Scanning of Roller Shutter Doors

Abstract

This invention discloses a lidar and detection method for synchronous scanning of roller shutter door horizontal exposure and point laser. The lidar includes a point light source rotation mechanism and an image sensor mechanism. The rotation speed of the point light source rotation mechanism is consistent with the scanning speed of the image sensor mechanism, and they are phase-synchronized. The area illuminated by the laser is located on the area corresponding to the line of exposure of the roller shutter door by the image sensor mechanism. This invention proposes to use point laser rotation scanning, combined with synchronous scanning of the roller shutter door horizontal exposure, to achieve line laser function. By rotating the point light source rotation mechanism, a laser point is scanned into a laser line in space, and the rotation of the laser point is synchronized with the frame rate of the image sensor mechanism. This allows low-power point laser to achieve the effect of line laser and can be used in civilian equipment.

Description

Technical Field

[0001] This invention relates to the field of lidar technology, and in particular to a lidar and detection method for simultaneous exposure and point laser scanning of roller shutter doors. Background Technology

[0002] Existing ranging solutions on the market include triangulation ranging and time-of-flight ranging. Among them, LiDAR based on triangulation ranging has a wide range of applications. Common triangulation ranging methods on the market include structured light ranging, line laser ranging, and LDS laser ranging radar for small, slow, and low-precision applications such as robotic vacuum cleaners.

[0003] Line lasers are mainly used for parts inspection in industrial products, small object contour recognition, and terrain environment scanning. By measuring different distances, information on the unevenness of the scanned surface can be obtained to determine whether there are defects in the parts. In the field of industrial robots, they can also be used to scan the surrounding environment to obtain terrain information and to identify small objects to obtain object contour information (this refers to robot scenarios, including terrain recognition and small object recognition).

[0004] LDS radar's single-point laser is mainly used in civilian laser ranging products, such as household robot vacuum cleaners, which use the rotation of point lasers and triangulation to obtain a 2D map of the surrounding environment.

[0005] However, line lasers do not meet civilian standards due to their requirement for high instantaneous laser power; and single-point lasers from LDS radars cannot meet the market's urgent demand for civilian laser ranging products due to their poor angular accuracy and large angular resolution.

[0006] In terms of both point lasers and line lasers:

[0007] (1) LDS ranging radar based on point laser scanning: LDS radar achieves single-point ranging using a single-point laser and sensor via triangulation, and then achieves a maximum ranging range of 360 degrees through a rotating mechanism. The basic principle of point laser triangulation is to emit one or more laser beams at a certain angle from a semiconductor laser to illuminate the object being measured. The reflected light is focused onto a CCD by a lens, and the actual distance to the object is calculated by the imaging position of the laser spot and the geometric relationship between the laser and the CCD. However, point laser radar has poor angular accuracy and can only perform single-line measurements. In traditional LDS radar, both the sensor and laser are located on rotating components, requiring high rotational power and incurring high costs for electrical and signal transmission facilities.

[0008] (2) Line lidar, using a single-line laser and an image sensor, can obtain depth data along a straight line through triangulation. Due to its high camera resolution and long baseline, it offers very high testing accuracy at close range. Line laser triangulation primarily involves illuminating the target with a line laser beam at a specific incident angle. The reflected light is focused onto a CCD image by a lens, and the actual distance to the object is calculated from the image position of the line laser beam. However, line lidar requires high instantaneous laser power for testing distant objects, which cannot meet laser safety requirements. It can only be used for short-range measurements, and the sensor needs to use a global shutter, which is expensive and not widely adopted.

[0009] For civilian line laser scanning equipment with high precision requirements, both safe, low-power lasers and rapid, accurate measurement results are needed, but currently, it is not possible to achieve both simultaneously. Therefore, the contradiction between high-frequency, high-precision line laser ranging and safe output power is a problem that urgently needs to be solved by professionals in this field. Summary of the Invention

[0010] The purpose of this invention is to provide a lidar and detection method for simultaneous exposure and point laser scanning of roller shutter doors, which solves the problems of existing line laser products that may cause harm to the human eye due to excessively high laser power and the poor accuracy of LDS radar, which can only perform single-line scanning.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0012] In a first aspect, embodiments of the present invention provide a lidar for synchronous scanning of roller shutter door exposure and point laser, comprising: a point light source rotation mechanism and an image sensor mechanism;

[0013] The rotation speed of the point light source rotation mechanism is consistent with the scanning speed of the image sensor mechanism and is phase-synchronized, so that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism.

[0014] Furthermore, the point light source rotation mechanism includes: a rotary motor with an encoder, a rotary disk, and one or more point lasers;

[0015] Wherein, when there is one point laser, the laser is spaced at a preset distance from the image sensor mechanism and the scanning direction is consistent; when there are multiple point lasers, they are arranged circumferentially along the rotating disk.

[0016] The rotary motor with encoder drives the rotary disk to rotate, which in turn drives the dot laser to rotate;

[0017] The rotational speed of the point laser is consistent with the scanning speed of the image sensor mechanism, and the phase is synchronized, so that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism.

[0018] Furthermore, the image sensor mechanism includes one or more cameras;

[0019] When there are multiple cameras, they are arranged circumferentially along the extension of the rotation axis; when there is only one camera, the scanning direction of the camera is consistent with the laser scanning direction of the point light source rotation mechanism, and the camera is spaced at a preset distance from the point light source rotation mechanism.

[0020] Furthermore, the image sensor mechanism is a binocular camera.

[0021] Furthermore, the rotating disk includes an upper rotating disk and a lower rotating disk; both the upper and lower rotating disks are provided with the same number of point lasers, which are arranged circumferentially along their respective rotating disks, and their positions correspond vertically.

[0022] The upper and lower turntables rotate in opposite directions, so that the scanning direction of the laser mounted on the point light source rotation mechanism corresponds to the exposure line of the laser spot projection;

[0023] The image sensor mechanism can be multiple cameras or a wide-angle camera; when it is multiple cameras, they are arranged circumferentially along the extension of the rotation axis.

[0024] The upper and lower turntables rotate in opposite directions, causing the point laser to rotate into a line, corresponding to the top-to-bottom exposure sequence of the roller shutter.

[0025] Furthermore, the point light source rotation mechanism includes: one set of rotation structures or two sets of rotation structures;

[0026] Each set of rotating structures includes: a rotary motor with an encoder, a rotating disk, a point laser, and a reflector assembly;

[0027] The reflector assembly is mounted on the rotating disk; the rotary motor with an encoder drives the rotating disk to rotate, thereby rotating the reflector assembly; the laser emitted from the point laser is incident on the reflector assembly.

[0028] When the reflector assembly rotates, it ensures that the rotation speed of the emitted laser is consistent with the scanning speed of the image sensor mechanism, so that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism.

[0029] When the point light source rotation mechanism includes two sets of rotation structures, they are two sets of rotation structures arranged vertically along the same rotation axis; wherein, in the first set of rotation structures and the second set of rotation structures, the rotation directions of their respective rotating disks are opposite and the positions of their respective reflector assemblies are opposite.

[0030] Furthermore, the reflector assembly includes a triangular reflector and a semi-transparent, semi-reflective mirror;

[0031] The laser emitted from the point laser is incident on the triangular reflector and then reflected into the semi-transparent mirror, splitting into two beams: one is transmitted light and the other is reflected light.

[0032] The two beams initially hit the field of view (FOV) corresponding to the first row of pixels of the image sensor mechanism. The rotary motor drives the reflector assembly to rotate, so that the rotation speed of the two beams is consistent with the row scanning speed of the image sensor mechanism, so that the laser always shines on the FOV corresponding to the row exposed by the image sensor mechanism.

[0033] Furthermore, the mirror assembly includes two mirrors combined together;

[0034] The laser emitted from the point laser is incident at the intersection of the two reflectors and splits into two beams: one is the upper reflected beam and the other is the lower reflected beam; the intersection is a point on the rotation axis.

[0035] The two beams initially hit the field of view (FOV) corresponding to the first row of pixels of the image sensor mechanism. The rotary motor drives the reflector assembly to rotate, so that the rotation speed of the two beams is consistent with the row scanning speed of the image sensor mechanism, thus ensuring that the laser continuously illuminates the FOV corresponding to the exposed row of the image sensor mechanism.

[0036] Furthermore, the point light source rotation mechanism includes: a rotary motor with an encoder, a rotating disk, a point laser source, and a multi-faceted frustum-shaped reflector;

[0037] When the point laser source is a single point laser, the laser and the image sensor mechanism are spaced at a preset distance and have the same scanning direction; when the point laser source is multiple point lasers, the multiple point lasers are arranged circumferentially along the extension line of the rotation axis.

[0038] The multifaceted frustum-shaped reflector is mounted on the rotating disk; the rotary motor with an encoder drives the rotating disk to rotate, which in turn drives the multifaceted frustum-shaped reflector to rotate; when the multifaceted frustum-shaped reflector rotates, the light output direction will change due to the different angles between the reflecting surface and the laser, resulting in multiple reflected lasers with different light output angles.

[0039] The rotation speed of the alternating multiple reflected lasers is consistent with the scanning speed of the image sensor mechanism, so that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism.

[0040] Secondly, the present invention also provides a detection method for a laser radar that simultaneously scans the roller shutter door's horizontal exposure and point laser scanning, using the laser radar that simultaneously scans the roller shutter door's horizontal exposure and point laser scanning as described in the above embodiments to achieve distance measurement of a target object; the method includes:

[0041] (1) Control the rotation speed of the point light source rotation mechanism to be consistent with and phase-synchronized with the scanning speed of the image sensor mechanism, so that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism.

[0042] (2) Based on the laser emission angle and baseline distance in the point light source rotation mechanism, after being scanned by the image sensor mechanism, the distance to the target object is obtained by triangulation.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The laser radar for synchronous scanning of roller shutter door exposure and point laser scanning provided in this invention includes: a point light source rotation mechanism and an image sensor mechanism; the rotation speed of the point light source rotation mechanism is consistent with the scanning speed of the image sensor mechanism, and the phase is synchronized, so that the area illuminated by the laser is located on the area corresponding to the line of exposure of the roller shutter door by the image sensor mechanism. This invention proposes to use point laser rotation scanning, combined with synchronous scanning of roller shutter door to achieve line laser function. It scans a laser line in space by rotating the point light source rotation mechanism, and synchronizes the rotation of the laser point with the frame rate of the image sensor mechanism, which can achieve the effect of line laser with low-power point laser and be applied to civilian equipment. Attached Figure Description

[0045] Figure 1 A schematic diagram of the structure and rotating scanning principle of a lidar for synchronous scanning of row exposure and point laser for roller shutter doors provided in an embodiment of the present invention;

[0046] Figure 2 A structural diagram of a roll-up door exposure camera;

[0047] Figure 3 This is a schematic diagram of the camera frame rate synchronization signal output.

[0048] Figure 4 A schematic diagram illustrating line laser testing using a rolling shutter door camera and a single laser source;

[0049] Figure 5 A schematic diagram illustrating line laser testing using a rolling shutter door camera and a multi-point laser source;

[0050] Figure 6a A schematic diagram illustrating line laser testing using a binocular camera and a single laser source;

[0051] Figure 6b This is a schematic diagram illustrating the principle of distance calculation using the trigonometric method.

[0052] Figure 7a This is a schematic diagram of the structure of the lidar with a camera in Embodiment 1 of the present invention;

[0053] Figure 7b This is a schematic diagram of the structure of the lidar with multiple cameras in Embodiment 1 of the present invention;

[0054] Figure 7c This is a schematic diagram of the laser radar using a binocular camera in Embodiment 1 of the present invention;

[0055] Figure 8 This is a schematic diagram of the lidar using dual turntables and an ultra-wide-angle camera in Embodiment 2 of the present invention;

[0056] Figure 9a This is a schematic diagram of the structure of the lidar using a triangular reflector assembly and a camera in Embodiment 3 of the present invention;

[0057] Figure 9b This is a schematic diagram of the structure of the lidar using a triangular reflector assembly and multiple cameras in Embodiment 3 of the present invention;

[0058] Figure 9c This is a schematic diagram of the lidar in Embodiment 3 of the present invention, which employs two sets of rotating structures and an ultra-wide-angle camera.

[0059] Figure 9d This is a schematic diagram of the laser radar using a binocular camera in Embodiment 3 of the present invention;

[0060] Figure 10a This is a schematic diagram of the structure of the lidar in Embodiment 4 of the present invention, which uses two mirrors combined together and a camera.

[0061] Figure 10b This is a schematic diagram of the structure of the lidar in Embodiment 4 of the present invention, which uses two combined reflectors and multiple cameras;

[0062] Figure 10c This is a schematic diagram of the lidar in Embodiment 4 of the present invention, which employs two sets of rotating structures and an ultra-wide-angle camera.

[0063] Figure 10d This is a schematic diagram of the structure of the lidar in Embodiment 4 of the present invention, which employs a set of rotating structures and a binocular camera;

[0064] Figure 11a This is a schematic diagram of the point laser of the lidar in Embodiment 5 of the present invention being emitted on an inclined side of a reflector.

[0065] Figure 11b This is a schematic diagram showing the point laser of the lidar in Embodiment 5 of the present invention emanating from the other inclined side of the reflector.

[0066] Figure 11c This is a schematic diagram of the structure of the lidar using multiple lasers and multiple cameras in Embodiment 5 of the present invention;

[0067] Figure 11d This is a schematic diagram of the structure of the lidar in Embodiment 5 of the present invention, which uses a laser and a binocular camera. Detailed Implementation

[0068] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0069] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0070] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc., should be understood in a broad sense. For example, "connected" may refer to a fixed connection, a detachable connection, or an integral connection; it may refer to a mechanical connection or an electrical connection; it may refer to a direct connection or an indirect connection through an intermediate medium; it may refer to internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0071] The present invention provides a lidar for synchronous scanning of roller shutter door exposure and point laser, comprising: a point light source rotation mechanism and an image sensor mechanism;

[0072] The image sensor mechanism is located above or below the point light source rotation mechanism and is used to receive the laser reflected back from the point light source. The rotation speed of the point light source rotation mechanism is adjustable, and its rotation speed is consistent with and phase-synchronized with the scanning speed of the image sensor mechanism, so that the area illuminated by the laser is on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism.

[0073] This invention proposes using point lasers to achieve line laser functionality. It distributes laser points along a straight line by rotating a point light source mechanism. For example, it uses a photoelectric encoder to synchronize the laser emission and the image sensor's frame reception, ensuring that the area illuminated by the laser falls precisely on the area corresponding to the line of exposure in the image sensor mechanism. This achieves the effect of using low-power laser points instead of line lasers without harming the human eye. The overall structure is shown in the diagram below. Figure 1 As shown. In specific implementation, it includes the following parts: rotation of the point light source rotation mechanism, synchronous acquisition by the image sensor mechanism, synchronous control of the light source rotation and the frame rate of the image sensor mechanism, and finally, calculation of distance using the triangulation method.

[0074] 1) Rotation of the point light source rotating mechanism:

[0075] It can be the rotation of the laser point source, or the rotation of the light can be achieved by rotating the reflector assembly; in specific implementation, the speed of the motor with encoder is adjustable, and the position and speed of the laser beam can be fed back, so as to realize the rotation of the point source or the emitted light beam, which is synchronized with the exposure line of the image sensor mechanism.

[0076] 2) Image sensor mechanism:

[0077] It consists of one or more roller shutter-type exposure cameras, which can also be wide-angle or ultra-wide-angle cameras. Compared with ordinary cameras, wide-angle or ultra-wide-angle cameras have a larger field of view and cover a larger area.

[0078] like Figure 2 As shown, a typical camera consists of a lens, lens mount, narrowband filter, CMOS sensor, PCB / FPC, capacitors, resistors, reinforcement, etc.

[0079] Single-line and multi-line scanning are achieved by synchronously controlling the rotation speed of the point light source rotating mechanism and the camera exposure time:

[0080] like Figure 3 As shown, the camera captures images at a fixed frame rate, and a camera frame rate synchronization signal is output. The laser operates in constant-on mode, and during scanning, distance measurements within different fields of view (FOV) are achieved by adjusting the laser's rotation speed and synchronizing it with the camera-driven exposure time.

[0081] The camera's single-frame image resolution is m columns and n rows of pixels, with a frame rate of f. rate By adjusting the rotation speed of the point light source's rotating mechanism, line scanning of the camera's field of view (FOV) and resolution is achieved. Based on the principle of triangulation, when the distance to the reflective object in front of the light source changes, the corresponding image point on the camera appears as an image on the sensor. High-resolution scanning with a large FOV can be achieved through a combination of multiple cameras. The camera's exposure direction is synchronized with the point laser... Figure 4 As shown, the exposure direction can be adjusted to match the laser scanning direction by rotating the point light source or the emitted light beam.

[0082] Multi-line scanning is achieved by using multi-point light source synchronous scanning, such as... Figure 5 As shown.

[0083] (1) The rotation scanning of the control point light source rotation mechanism is synchronized with the image acquisition of the camera, so that when the first row of the camera begins to be exposed, the laser light spot hits the FOV corresponding to the first row of pixels of the camera, and the entire FOV is scanned in sequence.

[0084] (2) Control the rotation of the point light source rotation mechanism to synchronize with the camera exposure, so that the rotation speed of the point light source rotation mechanism is consistent with the speed of the camera line scanning.

[0085] Furthermore, in addition to the aforementioned ordinary camera, a binocular camera can also be used. For example, if the lidar uses a mechanical structure for rotation, when the rotation axis becomes loose, the position of the point light source will drift, making it difficult to distinguish changes in the distance to objects or changes in the position of the light spot caused by the jitter of the point light source. Therefore, a binocular camera can be used in conjunction with the laser of the point light source for synchronous distance measurement, which can effectively prevent ranging errors introduced by the rotational jitter of the laser; see, for example... Figure 6a As shown, the specific process can be referred to the binocular ranging principle in existing technologies.

[0086] 3) Calculate distance using trigonometric distance measurement:

[0087] like Figure 6b As shown, the laser source and the camera are on the same vertical line (called the baseline), with a distance of s between them, a camera focal length of f, and an angle of β between the light source and the baseline.

[0088] Suppose that the target object, Object, is reflected back to the camera's imaging plane at point P when illuminated by a point laser.

[0089] Based on geometric knowledge, similar triangles can be constructed. The triangle formed by the light source, camera, and target object is similar to the triangle formed by the camera, imaging point P, and auxiliary point P′.

[0090] Let PP′ = x, q, and d, as shown in Figure 6. Then, from similar triangles, we can obtain:

[0091] f / x=q / s→q=fs / x

[0092] It can be calculated in two parts:

[0093] x=x1+x2=f / tanβ+pixelSize*position

[0094] Where pixelSize is the size in pixels, and position is the pixel coordinate of the image relative to the image center. Finally, the distance d can be calculated: d = q / sinβ.

[0095] The structure of the lidar for synchronous scanning of roller shutter door row exposure and point laser is illustrated below through six more detailed embodiments:

[0096] Example 1:

[0097] Rotation of the laser point source:

[0098] The point light source rotation mechanism includes: a rotary motor with an encoder, a rotating disk, and one or more point lasers. When there is only one point laser, it can be positioned on the rotating shaft of the rotating disk. When there are multiple point lasers, they are arranged at unequal intervals or evenly along the circumference of the rotating disk. The rotary motor with the encoder drives the rotating disk to rotate, thereby rotating the point lasers. The rotational speed of the point lasers is consistent with and phase-synchronized with the scanning speed of the image sensor mechanism, ensuring that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter door of the image sensor mechanism. In this embodiment, the rotary motor with the encoder, the rotating disk, and their driving relationship are all commercially available components and will not be described in detail here.

[0099] like Figure 7a , 7b As shown, the image sensor assembly includes one or more cameras;

[0100] When there is one camera, the camera's scanning direction is consistent with the laser's scanning direction, and the camera and laser are arranged at a certain distance apart. This distance is related to the measured field of view (FOV) and the distance to the target. When there are multiple cameras, they are arranged circumferentially along the extension of the rotation axis. Additionally, as... Figure 7c As shown, the camera can also be a binocular camera, employing simultaneous scanning and ranging with the binocular camera and laser. The camera and laser rotation axis are coaxial, and the two cameras of the binocular camera can be placed on either side or on the same side of the laser for binocular ranging. By changing the number of binocular cameras and lasers, measurements at different FOVs and angles can be achieved. This improves system stability, has lower precision requirements for system structure compared to a monocular camera, and easily enables single-line and multi-line scanning ranging.

[0101] The working principle is as follows: The rotating disk drives the point laser to rotate, causing the laser points to scan in a ring. There can be one or more cameras and lasers; by changing the number of cameras and lasers, different FOVs and angles can be measured. When the camera begins exposure, the laser points initially hit the FOV corresponding to the first row of pixels on the camera, and the rotation speed of the laser points matches the camera's row scanning speed, sweeping across the entire FOV area. Because the multiple lasers on the rotating disk emit at different angles, after being scanned by the camera, precise distance values ​​can be obtained using triangulation based on their relative positions.

[0102] For example, when applying this LiDAR to an intelligent agent with a fixed movement trajectory, a single camera and laser are sufficient for distance measurement. However, when applying it to an intelligent agent without a planned path (such as a robotic vacuum cleaner), multiple cameras and multiple lasers can be used to achieve accurate distance measurement of surrounding objects. By using point lasers instead of line lasers, laser power is significantly reduced, lowering the price of the LiDAR while improving its eye safety.

[0103] Example 2:

[0104] Similar to Example 1, the rotation of the laser point source is also involved, referring to... Figure 8 As shown, unlike Embodiment 1, its rotating disk includes an upper rotating disk and a lower rotating disk; both the upper and lower rotating disks are equipped with the same number of point lasers, which are evenly arranged around their respective rotating disks, with their positions corresponding vertically; the upper rotating disk rotates clockwise, and the lower rotating disk rotates counterclockwise; the image sensor mechanism consists of multiple cameras or a wide-angle camera; when there are multiple cameras, they are evenly arranged around the extended line of the rotation axis; when there is a wide-angle camera, it is located on the extended line of the rotation axis; the clockwise and counterclockwise rotating disks drive the point lasers to rotate into a line, corresponding to the top-to-bottom exposure sequence of the roller shutter door.

[0105] In this embodiment, the rotary motor with encoder, the double-layer rotating disk rotating in different directions, and their driving relationship are all commercially available components, and will not be described in detail here.

[0106] The working principle is as follows: the upper turntable rotates clockwise, and the lower turntable rotates counterclockwise. The laser points of the two turntables scan the left and right sides of a row of sensors, respectively. The turntables need to scan at varying speeds to ensure the laser points hit the FOV (Field of View) area corresponding to the sensor's exposed row. When the camera begins exposure, the laser points hit the FOV corresponding to the first row of pixels on the camera, and the rotation speed of the laser points is synchronized with the camera's row scanning speed and phase. The clockwise and counterclockwise turntables drive the laser points to rotate in a linear pattern, corresponding to the top-to-bottom exposure sequence of the rolling shutter door. Because the multiple lasers on the turntables emit at different angles, after being scanned by the camera, precise distance values ​​can be obtained using triangulation based on their relative positions.

[0107] For example, a single fisheye lens can be used to achieve wide-angle ranging. In order to improve testing efficiency, in this embodiment, two turntables are used to rotate counterclockwise and clockwise respectively, so as to achieve ranging information from multiple lasers at different angles on a single line scan of the camera.

[0108] Example 3:

[0109] The rotation of light is achieved by rotating a mirror assembly:

[0110] The point light source rotation mechanism includes: one set of rotation structures or two sets of rotation structures;

[0111] Each set of rotating structures includes: a rotary motor with an encoder, a rotating disk, a point laser, and a reflector assembly; the reflector assembly is mounted on the rotating disk; the rotary motor with the encoder drives the rotating disk to rotate, thereby rotating the reflector assembly; a point laser is located on the extension line of the rotation axis, and the emitted laser light is incident on the reflector assembly; when the reflector assembly rotates, it ensures that the rotational speed of the emitted laser is consistent with and phase-synchronized with the scanning speed of the image sensor mechanism, so that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism.

[0112] When the point light source rotation mechanism includes two sets of rotation structures, they are two sets of rotation structures arranged vertically along the same rotation axis; wherein, in the first set of rotation structures and the second set of rotation structures, the rotation directions of their respective rotating disks are opposite and the positions of their respective reflector assemblies are opposite.

[0113] This structure achieves light rotation through the rotation of a reflector assembly, which reduces the number of lasers required; it can achieve dual-line scanning with a single laser, and a single laser can also achieve 360° scanning, and the assembly structure is relatively simple.

[0114] In this embodiment, the rotary motor with encoder, the rotary disk, and their driving relationship are all commercially available components, and will not be described in detail here.

[0115] The image sensor mechanism includes one or more cameras; the camera scanning direction is consistent with the laser scanning direction, and the camera and laser are arranged at a certain distance apart; when there are multiple cameras, the multiple cameras are arranged circumferentially along the extension line of the rotation axis.

[0116] like Figure 9a As shown, this image sensor mechanism uses a camera;

[0117] like Figure 9b As shown, the image sensor mechanism employs multiple cameras, which are evenly arranged circumferentially along the extension of the rotation axis.

[0118] like Figure 9cAs shown, the image sensor mechanism can employ an ultra-wide-angle camera.

[0119] Of course, such as Figure 9d As shown, the image sensor mechanism can also employ a binocular camera to perform scanning and ranging synchronously with the laser, with the binocular camera coaxial with the rotation axis.

[0120] like Figures 9a-9d As shown, the reflector assembly in the figure includes a triangular reflector and a semi-transparent mirror; the triangular reflector is a right triangle; when arranged, one right-angled side is parallel to the horizontal line, and the other right-angled side is parallel to the vertical line; the semi-transparent mirror is tilted, and the side closest to the triangular reflector forms an acute angle with the horizontal line when tilted.

[0121] The laser beam emitted from the point laser is incident on the center of the hypotenuse of a triangular mirror, and then reflected into the center of a semi-transparent mirror, splitting into two beams: one transmitted light and the other reflected light; the transmitted light is stronger, and the reflected light is weaker. Both beams initially illuminate the field of view (FOV) corresponding to the first row of pixels on the image sensor mechanism. The rotation speed of the two beams is consistent with the row scanning speed of the image sensor mechanism, ensuring that the laser continuously illuminates the FOV corresponding to the row being exposed by the image sensor mechanism.

[0122] The working principle is as follows: A laser point is reflected by a mirror onto a semi-transparent mirror, which then splits the laser into two points. When the camera begins exposure, the two laser points strike the field of view (FOV) corresponding to the first row of pixels on the camera, ensuring that the rotation speed of the laser points matches the camera's line scanning speed and is phase-synchronized. A motor drives the mirror to rotate, causing the laser point to form a line. As it passes through the semi-transparent mirror, it forms two lines, one vertical and one horizontal. Based on the camera's pinhole model, the two laser points can be distinguished by their vertical positions on the sensor. After being scanned by the camera, the precise distance can be obtained using triangulation based on their relative positions.

[0123] For example, refer to Figure 9a As shown, if this lidar is applied to an intelligent agent with a fixed motion trajectory, then a camera, a laser, and a set of reflector components are sufficient to achieve dual-line scanning with a single laser, thus meeting the distance measurement requirements.

[0124] Reference Figure 9b As shown, when this LiDAR is applied to intelligent agents without a planned path (such as a robot vacuum cleaner), multiple cameras, a laser, and a set of reflector components can be used to achieve accurate distance measurement of surrounding objects.

[0125] Reference Figure 9c As shown, for example, two sets of rotating structures and an ultra-wide-angle camera can be used to achieve a wider range and more accurate distance measurement.

[0126] Reference Figure 9dAs shown, for example, a set of rotating structures and binocular cameras can be used in conjunction with a laser source with a point light source to perform distance testing synchronously. This can effectively prevent ranging errors caused by laser rotation jitter. Correction of ranging errors can improve system stability. Compared with monocular cameras, it has lower requirements for the precision of the system structure and is easy to achieve single-line and multi-line scanning ranging.

[0127] Example 4:

[0128] The difference from Example 3 is that this reflector assembly includes two reflectors combined together; compared to the structure of Example 3, it has a smaller space but requires higher precision in the alignment of the rotating shaft.

[0129] like Figure 10a As shown, the image sensor mechanism uses a camera located on the extension of the rotation axis;

[0130] like Figure 10b As shown, the image sensor mechanism employs multiple cameras, which are evenly arranged circumferentially along the extension of the rotation axis.

[0131] like Figure 10c As shown, two sets of rotating structures are used. The image sensor mechanism employs an ultra-wide-angle camera, which is arranged along the extension line of the rotation axis.

[0132] like Figure 10d As shown, a rotating structure is employed. This image sensor mechanism uses a binocular camera, with two cameras positioned along the extension of the rotation axis on either side of the laser. This improves the stability of the testing system. The binocular camera and laser scan and measure distance simultaneously. The camera is coaxial with the rotation axis and can be placed on either side or the same side of the laser. Different FOV measurements can be achieved by changing the number of binocular cameras.

[0133] like Figures 10a-10d As shown, the mirror assembly in the figure includes a right-angled trapezoidal mirror and a right-angled triangular mirror. When arranged, the two parallel sides of the right-angled trapezoidal mirror have the longer side being the same length as one of the right-angled sides of the right triangle. The two sides of the same length are joined together, parallel to the horizontal line. The laser emitted from the point laser is incident at the intersection of the two mirrors, which is also the intersection of the two hypotenuses. Two beams are split: one is the upper reflected beam, and the other is the lower reflected beam. This intersection is a point on the rotation axis. The two beams strike the field of view corresponding to the first row of pixels in the image sensor mechanism, and the rotation speed of the two beams is consistent with the row scanning speed of the image sensor mechanism.

[0134] That is, the two beams initially hit the field of view corresponding to the first row of pixels of the image sensor mechanism. The rotating motor drives the mirror assembly to rotate, so that the rotation speed of the two beams is consistent with the row scanning speed of the image sensor mechanism, so that the laser always shines on the FOV corresponding to the exposed row of the image sensor mechanism.

[0135] The working principle is as follows: A laser point is struck at the intersection of two reflectors, splitting into two laser points. When the camera begins exposure, the two laser points strike the field of view (FOV) corresponding to the first row of pixels on the camera, ensuring the laser points rotate at the same speed and in phase with the camera's line scanning speed. A motor drives the reflectors to rotate, causing the laser points to form lines. Because they strike the intersection of the two reflectors, two lines are formed, one vertically and one horizontally. Based on the camera's pinhole model, the two laser points can be distinguished by their vertical positions on the sonsor. After being scanned by the camera, precise distance values ​​can be obtained using triangulation based on their relative positions.

[0136] For example, if this lidar is applied to an intelligent agent with a fixed motion trajectory, then a single camera, a laser, and two combined reflectors are sufficient to meet the ranging requirements. Using two combined reflectors effectively reduces the horizontal volume of the lidar, providing more design space for other components.

[0137] Example 5:

[0138] The difference from Embodiment 3 is that the reflector assembly is a multi-faceted frustum-shaped reflector, such as a frustum-shaped reflector with multiple inclined sides of different slopes; there are one or more point laser sources; a single reflector is used to achieve dual-line or multi-line scanning of a single laser. This structure is simple, can achieve multi-angle scanning with a single light source, and does not require high precision in axis alignment. However, multi-line switching is performed in each rotation cycle, which sacrifices the frame rate.

[0139] When the point laser source is a single point laser, such as Figure 11a , 11b As shown in Figure 11d, a point laser is located on one side of the extension line of the rotation axis; when the point laser source is multiple point lasers, the multiple point lasers are evenly arranged circumferentially along the extension line of the rotation axis.

[0140] The multifaceted frustum-shaped reflector is mounted on a rotating disk; a rotary motor with an encoder drives the rotating disk to rotate, which in turn drives the multifaceted frustum-shaped reflector to rotate; when laser light is irradiated onto the reflectors at different angles, laser beams can be emitted at different angles.

[0141] The rotational speed of the two alternating reflected lights is consistent with and phase-synchronized with the scanning speed of the image sensor mechanism, so that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism.

[0142] like Figure 11a As shown, the image sensor mechanism employs a camera located on the extension of the rotation axis; the point laser of the lidar emits light onto an inclined side of a reflector; as... Figure 11b As shown, the point laser of the lidar is emitted from the other inclined side of the reflector.

[0143] like Figure 11c As shown, the image sensor mechanism can employ multiple cameras, which are uniformly arranged circumferentially along the extension of the rotation axis.

[0144] like Figure 11d As shown, the image sensor mechanism can use a binocular camera, which can improve the stability of the test system. The binocular camera and the laser are scanned and measured together. The camera and the rotating axis of the reflector are coaxial and can be placed on both sides or the same side of the laser. Different FOV measurements can be achieved by changing the number of binocular cameras.

[0145] like Figures 11a-11d As shown, the mirror assembly in the figure has a frustum-shaped mirror with two inclined sides of different slopes; when arranged, the two parallel sides are parallel to the horizontal line.

[0146] The working principle is as follows: Figure 11a As shown, the laser beam strikes the surface of the mirror with a high slope, resulting in an upward-sloping reflected beam; the motor drives the mirror to rotate, as... Figure 11b As shown, the laser point strikes the surface of the reflector with a low slope, resulting in a downward-sloping reflected light. When the camera begins exposure, the laser point strikes the FOV corresponding to the first row of pixels on the camera, and the laser point's rotation speed is synchronized with the camera's line scanning speed and phase. The motor drives the reflector to rotate, causing the laser point to form a line, with multiple reflected lights appearing alternately. This allows for the projection of light rays at different angles. After being scanned by the camera, the distance values ​​for different emission angles can be obtained using triangulation based on the relative position and the laser emission angle corresponding to the current frame imaged by the camera. This achieves time-division multi-line measurement results.

[0147] Depending on the specific application scenario, the lidar of the above five embodiments can be selected. The lidar of this invention achieves high-precision ranging measurement while meeting laser safety power requirements by replacing line lasers with low-power laser points. Existing technologies using eye-safe point laser scanning only achieve around 2300Hz, with an angular resolution of only 1°. This invention, by combining the advantages of line lasers, significantly improves accuracy. For example, a 120° FOV camera, corresponding to a common 1600x1200 (OV2640) resolution 15Hz sensor, can easily achieve an angular resolution of 120 / 1200 = 0.1 degrees, with a point output rate of 15*1200 = 18,000. Furthermore, 360° scanning can be achieved through multi-camera or special system designs (such as fisheye lenses). Additionally, multi-line scanning applications can be achieved through multiple laser projection directions. For example, in robotic vacuum cleaners, it can replace the functions of multiple sensors, including LDS radar, wall-following line laser sensors, and cliff sensors, resulting in lower costs, a simpler system, and greater device intelligence. It meets the urgent needs of the current market and provides a better solution for civilian laser ranging products in the market.

[0148] Based on the same inventive concept, this invention also provides a detection method for a lidar that uses row exposure and point laser synchronous scanning for roller shutter doors. Since the principle of the problem solved by this method is similar to that of the lidar that uses row exposure and point laser synchronous scanning for roller shutter doors, the implementation of this method can refer to the implementation of the lidar device described above, and the repeated parts will not be described again.

[0149] The detection method of the lidar with synchronous scanning of line exposure and point laser for roller shutter doors provided in the embodiments of the present invention uses the lidar with synchronous scanning of line exposure and point laser for roller shutter doors as described in any of the above embodiments to achieve ranging of target objects; the method includes:

[0150] (1) Control the rotation speed of the point light source rotation mechanism to be consistent with and phase-synchronized with the scanning speed of the image sensor mechanism, so that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism.

[0151] (2) Based on the laser emission angle and baseline distance in the point light source rotation mechanism, after being scanned by the image sensor mechanism, the distance to the target object is obtained by triangulation.

[0152] Compared with existing technologies, this invention uses a low-power single-point light source to achieve single-line and multi-line scanning. This solution has wide applicability and high eye safety. The distance to the target object is obtained by triangulation, which is convenient, efficient and accurate.

[0153] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A lidar system for synchronous scanning of roller shutter doors using both linear exposure and point laser scanning, characterized in that, include: Point light source rotation mechanism and image sensor mechanism; The rotation speed of the point light source rotating mechanism is consistent with the scanning speed of the image sensor mechanism and is phase synchronized, so that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism. The point light source rotation mechanism has a rotating disk; The rotating disk includes an upper rotating disk and a lower rotating disk; both the upper and lower rotating disks are equipped with the same number of point lasers, which are arranged circumferentially along their respective rotating disks, and their positions correspond vertically. The upper and lower turntables rotate in opposite directions, so that the scanning direction of the laser mounted on the point light source rotation mechanism corresponds to the exposure line of the laser spot projection; The image sensor mechanism can be multiple cameras or a wide-angle camera; when it is multiple cameras, they are arranged circumferentially along the extension of the rotation axis. The upper and lower turntables rotate in opposite directions, causing the point laser to rotate into a line, corresponding to the top-to-bottom exposure sequence of the roller shutter.

2. The lidar for synchronous scanning of roller shutter door horizontal exposure and point laser as described in claim 1, characterized in that, The image sensor mechanism is a binocular camera.

3. The lidar for synchronous scanning of roller shutter door horizontal exposure and point laser as described in claim 1, characterized in that, The point light source rotation mechanism can also be: two sets of rotation structures; Each set of rotating structures includes: a rotary motor with an encoder, a rotating disk, a point laser, and a reflector assembly; The reflector assembly is mounted on the rotating disk; the rotary motor with an encoder drives the rotating disk to rotate, thereby rotating the reflector assembly; the laser emitted from the point laser is incident on the reflector assembly. When the reflector assembly rotates, it ensures that the rotation speed of the emitted laser is consistent with the scanning speed of the image sensor mechanism, so that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism. The point light source rotation mechanism includes two sets of rotation structures, which are two sets of rotation structures arranged vertically along the same rotation axis; wherein, in the first set of rotation structures and the second set of rotation structures, the rotation directions of their respective rotating disks are opposite and the positions of their respective reflector assemblies are opposite.

4. The lidar for synchronous scanning of roller shutter door row exposure and point laser as described in claim 3, characterized in that, The mirror assembly includes a triangular mirror and a semi-transparent mirror; The laser emitted from the point laser is incident on the triangular reflector and then reflected into the semi-transparent mirror, splitting into two beams: one is transmitted light and the other is reflected light. The two beams initially hit the field of view (FOV) corresponding to the first row of pixels of the image sensor mechanism. The rotary motor drives the reflector assembly to rotate, so that the rotation speed of the two beams is consistent with the row scanning speed of the image sensor mechanism, so that the laser always shines on the FOV corresponding to the row exposed by the image sensor mechanism.

5. The lidar for synchronous scanning of roller shutter door horizontal exposure and point laser as described in claim 3, characterized in that, The mirror assembly includes two mirrors combined together; The laser emitted from the point laser is incident at the intersection of the two reflectors and splits into two beams: one is the upper reflected beam and the other is the lower reflected beam; the intersection is a point on the rotation axis. The two beams initially hit the field of view (FOV) corresponding to the first row of pixels of the image sensor mechanism. The rotary motor drives the reflector assembly to rotate, so that the rotation speed of the two beams is consistent with the row scanning speed of the image sensor mechanism, thus ensuring that the laser continuously illuminates the FOV corresponding to the exposed row of the image sensor mechanism.

6. The lidar for synchronous scanning of roller shutter door horizontal exposure and point laser as described in claim 3, characterized in that, The mirror assembly in each set of rotating structures can also be a multifaceted frustum-shaped mirror; each set of rotating structures can also include one or more point lasers. When the point laser source is a single point laser, the laser and the image sensor mechanism are spaced at a preset distance and have the same scanning direction; When the point laser source is multiple point lasers, the multiple point lasers are arranged circumferentially along the extension of the rotation axis. The multifaceted frustum-shaped reflector is mounted on the rotating disk; the rotary motor with an encoder drives the rotating disk to rotate, which in turn drives the multifaceted frustum-shaped reflector to rotate; when the multifaceted frustum-shaped reflector rotates, the light output direction will change due to the different angles between the reflecting surface and the laser, resulting in multiple reflected lasers with different light output angles. The rotation speed of the alternating multiple reflected lasers is consistent with the scanning speed of the image sensor mechanism, so that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism.

7. A detection method for a lidar system using simultaneous exposure and point laser scanning on roller shutter doors, characterized in that, Using the lidar with synchronous scanning of roller shutter door exposure and point laser as described in any one of claims 1-6, the distance to the target object is measured. The method includes: (1) Control the rotation speed of the point light source rotation mechanism to be consistent with and phase-synchronized with the scanning speed of the image sensor mechanism, so that the area illuminated by the laser is located on the area corresponding to the line exposed by the roller shutter of the image sensor mechanism. (2) Based on the laser emission angle and baseline distance in the point light source rotation mechanism, after being scanned by the image sensor mechanism, the distance to the target object is obtained by triangulation.

Images