Symmetrical cross type binocular line laser rotary scanning three-dimensional measurement method and sensor

Abstract

The application provides a symmetric cross type binocular line laser rotary scanning three-dimensional measurement method and sensor, relates to the three-dimensional scanning measurement technical field, and first and second measurement units are symmetrically arranged about the center of the rotation axis, so that the instantaneous combined field of view of the sensor is doubled, and the maximum rotation angle required for the same total scanning field of view is much smaller than that of a monocular scheme; and the cross light path design of the camera-opposite laser is adopted, for any point on the surface of the measured object, there are two independent measurement paths which are symmetric about the rotation axis and have opposite light path directions, when one of the light paths is blocked by the complex structure of the object, the other light path is highly likely to remain unobstructed, forming measurement redundancy in physical structure, and greatly reducing the point cloud missing rate. In the field of view overlap area, the same point can be independently detected by two sets of triangulation measurement systems, which can be effectively supplemented and verified for triangulation, while improving the measurement accuracy, further ensuring the reliability of the three-dimensional reconstruction result.

Description

Technical Field

[0001] This application relates to the field of three-dimensional scanning measurement technology, and more specifically, to a symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method and sensor. Background Technology

[0002] In fields such as industrial inspection, reverse engineering, and intelligent manufacturing, 3D scanning measurement technology is being used more and more widely. To meet the need for large-scale surface scanning, existing technologies often employ a single-set line laser profilometer (see the attached manual). Figure 1 The proposed solution, consisting of a camera and a line laser mounted on a rotating platform, expands the "line scan" of a single laser line into a "surface scan" covering a fan-shaped or conical region through the rotational motion of the platform, ultimately stitching together the data to form a 3D point cloud of the object being measured. This existing technical solution mainly includes a rotation drive mechanism, a rotating support, and a single camera and a single laser fixed on the support. The camera and laser are located on the same side or adjacent to the rotation axis, forming a single-optical optical measurement unit. During scanning, a motor drives the measurement unit to rotate, and the camera triggers an image at a preset angle. The cross-sectional contour is calculated using triangulation and stitched together to form a 3D point cloud.

[0003] However, this technology has obvious defects. (1) There is an inherent contradiction between the scanning range and the size of the equipment: In order to obtain a larger scanning field of view, the rotation angle must be increased, which directly leads to an increase in the motion envelope of the rotating parts and a significant increase in the size (diameter or thickness) of the sensor in the direction of the rotation axis, making it difficult to install and integrate in industrial sites with limited space. (2) Poor anti-obstruction ability and serious data loss: In the measurement mode of single view and single optical path, when scanning workpieces with complex geometry, deep holes, steep sidewalls or internal depressions, the laser line or reflected light is easily blocked by the characteristics of the object itself, which cannot form an effective image, resulting in the loss of three-dimensional point cloud data and the inability to guarantee the integrity of the measurement. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method and sensor, which can realize large field-of-view three-dimensional scanning in a compact volume, while greatly improving the sensor's anti-occlusion ability and ensuring the integrity of measurement data.

[0005] In a first aspect, embodiments of this application provide a symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method, applied to a symmetrical cross-type binocular laser rotation scanning three-dimensional sensor. The sensor includes a rotation drive mechanism, a rotation support, a first measurement unit, and a second measurement unit. The first and second measurement units are symmetrically distributed about the rotation axis of the rotation drive mechanism and fixed to the rotation support. The first measurement unit includes a first camera and a second laser located on the opposite side of its rotation axis, forming a first measurement optical path. The second measurement unit includes a second camera and a first laser located on the opposite side of its rotation axis, forming a second measurement optical path. The method includes the following steps: The internal parameters of the first camera and the second camera are calibrated respectively, as are the equations of the first laser plane of the first laser and the second laser plane of the second laser in the coordinate system of the first camera. The coordinate systems of the first camera and the second camera are then aligned with the global coordinate system fixed to the rotation axis. The rotation drive mechanism is activated, and rotation angle data is acquired in real time. When the object rotates to the first angle, the second laser is triggered to emit light and the first camera captures the first image of the object under test. When the object rotates to the second angle, the first laser is triggered to emit light and the second camera captures the second image of the object under test. Based on the first image and the equation of the second laser plane, the first three-dimensional point cloud is calculated using triangulation. Based on the second image and the equation of the first laser plane, the second three-dimensional point cloud is calculated using triangulation. The first and second three-dimensional point clouds are then transformed to the global coordinate system and fused and deduplicated sequentially to output the final three-dimensional point cloud.

[0006] In some embodiments, calibrating the internal parameters of the first camera and the second camera, and the first laser plane equation of the first laser in the second camera coordinate system and the second laser plane equation of the second laser in the first camera coordinate system, respectively, includes the following steps: The first and second cameras are controlled to acquire multiple sets of calibration images of the checkerboard calibration board in different poses. The reference parameter sets of the first and second cameras are obtained through the camera calibration algorithm. The reference parameters include the intrinsic parameter matrix, distortion coefficients, and focal length. The laser line image on the target is acquired by the first measurement unit, and the target is moved to different positions for repeated acquisition. The sub-pixel center coordinates of the laser line in all images are extracted. Combined with the reference parameter set of the second camera and the world coordinate system equation of the target plane, the first laser plane equation of the first laser in the second camera coordinate system is obtained by fitting. Furthermore, the equation of the second laser plane of the second laser in the first camera coordinate system is obtained through the same calibration logic.

[0007] In some embodiments, the step of connecting the first camera coordinate system, the second camera coordinate system, and a global coordinate system fixed to the rotation axis includes the following steps: The calibration object is fixed on the rotary table and its center is aligned with the rotation axis. The rotation drive mechanism is controlled to rotate the camera to multiple angles, and the calibration object is photographed by the first camera and the second camera respectively. Preliminary 3D reconstruction is performed on images captured from various angles based on the reference parameter set of the binocular camera to obtain multi-view discrete point cloud data of the calibration object. Using the Iterative Closest Point (ICP) algorithm, all multi-view point clouds are aligned to a preset global coordinate system. By solving the coordinate transformation relationship through point cloud spatial matching, the transformation matrix from the first camera coordinate system to the world coordinate system and the transformation matrix from the second camera coordinate system to the world coordinate system are obtained.

[0008] In some embodiments, the rotary drive mechanism employs a scanning strategy triggered at equal angular intervals, wherein laser emission and image acquisition are performed once for each fixed rotation angle, and multiple sets of data acquisitions are completed in a single rotation; and the two measurement optical paths are triggered sequentially in a manner with half-intervals at different angles.

[0009] In some embodiments, the step of calculating the first three-dimensional point cloud based on the first image and the second laser plane equation using triangulation includes the following steps: After performing distortion correction on the first image based on the distortion coefficients of the first camera, image processing including filtering and binarization is performed to obtain the first optimized laser line image. The Steger algorithm is used to extract the sub-pixel center coordinates of the laser line in the first optimized image, and based on the intrinsic parameter matrix of the first camera, the sub-pixel center coordinates are back-projected into a spatial ray in the coordinate system of the first camera. Solve the equations of the spatial ray and the second laser plane simultaneously to obtain the coordinates of the intersection point of the ray and the laser plane, and integrate all the intersection point coordinates into the first three-dimensional point cloud.

[0010] In some embodiments, the first three-dimensional point cloud and the second three-dimensional point cloud are superimposed in the same global coordinate system, and fusion and deduplication are performed using algorithms such as voxel rasterization.

[0011] Secondly, embodiments of this application provide a symmetrical cross-type binocular laser rotation scanning three-dimensional measurement sensor, including a rotation drive mechanism, a rotation bracket, a first measurement unit, and a second measurement unit; the first measurement unit and the second measurement unit are symmetrically distributed about the rotation axis of the rotation drive mechanism and fixed on the rotation bracket; wherein, the first measurement unit includes a first camera and a second laser located on the opposite side of its rotation axis, forming a first measurement optical path; the second measurement unit includes a second camera and a first laser located on the opposite side of its rotation axis, forming a second measurement optical path; used to collaboratively implement the steps of the symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method as described in any of the first aspects.

[0012] In some embodiments, it also includes: A rotary encoder, connected to a rotary drive mechanism, is used to acquire rotation angle signals; The synchronization control unit is electrically connected to the rotary encoder, the first camera, the second camera, the first laser, and the second laser, respectively, and is used to control the triggering sequence of each camera and laser; and filters are also provided in front of the lenses of the first camera and the second camera.

[0013] Thirdly, an electronic device provided in this application includes a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. When the machine-readable instructions are executed by the processor, the steps of the symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method described in any of the first aspects are executed.

[0014] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method described in any of the first aspects.

[0015] This application describes a symmetrical cross-type binocular laser rotation scanning 3D measurement method and sensor. The first and second measurement units are symmetrically arranged about the rotation axis, which multiplies the instantaneous joint field of view of the sensor. The maximum rotation angle required to achieve the same total scanning field of view is much smaller than that of a monocular solution. Furthermore, it employs a cross-optical path design between the camera and the opposite laser. For any point on the surface of the object being measured, there are two independent measurement paths symmetrical about the rotation axis and with opposite optical paths. When one optical path is blocked by the complex structure of the object, the other optical path is likely to remain unobstructed, creating measurement redundancy from a physical structure perspective and significantly reducing the point cloud missing rate. Additionally, in the overlapping field of view area, the same point can be independently detected by two triangulation measurement systems, serving as an effective supplement and verification of the triangulation method. This improves measurement accuracy while further ensuring the reliability of the 3D reconstruction results. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the structure of a prior art monocular single-laser rotating scanning sensor is shown; Figure 2 This paper shows a schematic diagram of the structure of a symmetrical cross-type binocular laser rotation scanning three-dimensional sensor according to an embodiment of this application; Figure 3 A flowchart of the symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method according to an embodiment of this application is shown; Figure 4 A structural block diagram of the electronic device described in an embodiment of this application is shown.

[0018] Explanation of key component symbols: 201. Rotary motor; 202. Rotary platform; 203. First camera; 204. Second laser; 205. Second camera; 206. First laser. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the accompanying drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0020] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0021] It should be noted that the term "comprising" will be used in the embodiments of this application to indicate the presence of the features declared thereafter, but does not exclude the addition of other features.

[0022] In view of the technical problems raised in the background art, this application provides a symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method and sensor, which can realize large field of view three-dimensional scanning in a compact volume, while greatly improving the sensor's anti-occlusion ability and ensuring the integrity of measurement data.

[0023] See the instruction manual appendix Figure 2 Included with instruction manual Figure 3 This application provides a symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method, applied to a symmetrical cross-type binocular laser rotation scanning three-dimensional sensor. The sensor includes a rotation drive mechanism, a rotation support, a first measurement unit, and a second measurement unit. The first and second measurement units are symmetrically distributed about the rotation axis of the rotation drive mechanism and fixed to the rotation support. The first measurement unit includes a first camera and a second laser located on the opposite side of its rotation axis, forming a first measurement optical path. The second measurement unit includes a second camera and a first laser located on the opposite side of its rotation axis, forming a second measurement optical path. The method includes the following steps: S1. Calibrate the internal parameters of the first camera and the second camera respectively, as well as the equations of the first laser plane of the first laser and the second laser plane of the second laser in the coordinate system of the first camera, and align the coordinate system of the first camera and the coordinate system of the second camera to the global coordinate system fixed to the rotation axis. S2. Start the rotation drive mechanism and acquire rotation angle data in real time. When rotating to the first angle, the second laser is triggered to emit light and the first camera captures the first image of the object under test. When rotating to the second angle, the first laser is triggered to emit light and the second camera captures the second image of the object under test. S3. Based on the first image and the equation of the second laser plane, the first three-dimensional point cloud is calculated using the triangulation method; based on the second image and the equation of the first laser plane, the second three-dimensional point cloud is calculated using the triangulation method; the first three-dimensional point cloud and the second three-dimensional point cloud are uniformly transformed to the global coordinate system, and then fused and deduplicated in sequence to output the final three-dimensional point cloud.

[0024] To clearly understand the technical solutions of the embodiments of the present invention, the applied sensors can be described first by way of example, which specifically include: The rotary drive mechanism, as shown in the figure, uses a stepper motor (model 57HS22, microstepping driver set to 16 microsteps) and a high-precision reducer (reduction ratio 10:1). The stepper motor output torque is ≥5 N. m, speed range 0.1~30 RPM; the output end of the stepper motor is connected to the high-precision reducer, and the output end of the high-precision reducer is connected to the rotating bracket through a rigid coupling to ensure no eccentric wobbling during rotation.

[0025] The rotating support, as shown in the figure, is a rotating platform 202. It is made of aviation aluminum 7075 as a whole, which is lightweight and has high rigidity. It has a cross-shaped symmetrical structure. Its center is fixed to the rotating shaft O of the rotating drive mechanism. The arm is 150 mm long, 60 mm wide, and 20 mm thick. The first measuring unit and the second measuring unit are installed at both ends respectively.

[0026] The first measurement unit and the second measurement unit are centrally symmetrical about the rotation axis O. The first measurement unit includes a first camera 203 and a second laser 204 located on the opposite side of the rotation axis, and the second measurement unit includes a second camera 205 and a first laser 206 located on the opposite side of the rotation axis. The first camera 203 and the second laser 204 form the first measurement optical path, and the second camera 205 and the first laser 206 form the second measurement optical path, realizing the cross pairing of "camera-opposite laser". The first camera 203 and the second camera 205 both use Basler acA2440-75um, with a resolution of 2448×2048, a pixel size of 3.45 µm, and a global shutter. The optical axes of the two cameras are parallel and 150 mm away from the rotation center. The first laser 206 is a red laser module with a wavelength of 650 nm, and the second laser 204 is a blue laser module with a wavelength of 450 nm. Both are line lasers with a linewidth of 0.1 mm, a divergence angle of 60°, and a power of 50 mW. The angle between the camera and the laser is 30°, and the laser points to the outside of the rotation axis.

[0027] The filtering assembly includes a first filter and a second filter; the first filter is disposed in front of the lens of the first camera 203 and is a narrowband filter with a center wavelength of 450 nm and a bandwidth of 10 nm, allowing blue light from the second laser 204 to pass through; the second filter is disposed in front of the lens of the second camera 205 and is a narrowband filter with a center wavelength of 650 nm and a bandwidth of 10 nm, allowing red light from the first laser 206 to pass through, thereby achieving optical path isolation and suppressing ambient light and laser crosstalk.

[0028] The rotary encoder is an incremental encoder with a resolution of 1024 PPR (lines / revolutions) and differential output. It is connected to the rotary motor 201 to acquire rotation angle signals and, together with the synchronous control unit, achieves an angle resolution of 0.09°.

[0029] The synchronous control unit uses a Xilinx Artix-7 FPGA controller with an integrated rotary encoder interface. It has four independent trigger outputs, which are electrically connected to the first camera 203, the second camera 205, the first laser 206, and the second laser 204, respectively. The trigger delay is <1μs, which can precisely control the trigger timing of each component.

[0030] Step S1 mainly involves eliminating the system's own errors and unifying the quantization benchmark of multiple sensors, so that subsequent image acquisition and data processing have accurate calculation basis.

[0031] In one embodiment, the intrinsic parameters of the first camera are first calibrated to generate a first camera reference parameter set. Specifically, the first camera is controlled to acquire 20 sets of calibration images of a checkerboard calibration board in different poses. Using the Zhang Zhengyou checkerboard calibration method, the images are subjected to distortion analysis and parameter calculation through a camera calibration algorithm to obtain the first camera intrinsic parameter reference set (including the intrinsic parameter matrix, distortion coefficients, focal length, principal point, and other core parameters). Based on the same calibration logic, a second camera intrinsic parameter reference set is obtained. This eliminates the camera's own optical distortion (such as radial and tangential distortion), establishing an optical quantization reference for the subsequent conversion of image pixel coordinates to spatial geometric coordinates, ensuring the resolution accuracy of a single frame image.

[0032] Next, the first laser plane equation is calibrated to generate the first laser plane reference parameters. Specifically, the first laser is triggered to emit light, and the second camera is controlled to acquire images of the laser lines on the target. The target is moved to at least 10 different positions for repeated acquisition, and the sub-pixel center coordinates of the laser lines in all images are extracted. Combining the second camera reference parameter set and the target plane world coordinate system equation, the laser plane spatial position is fitted using the least squares method to obtain the first laser plane equation of the first laser in the second camera coordinate system. And based on the same calibration logic, the second laser plane equation of the second laser in the first camera coordinate system is obtained. Thus, for the design of "camera and opposite laser cross pairing", the laser plane spatial position of the laser in the paired camera coordinate system is accurately calibrated, providing an optical path geometric reference for triangulation calculation of 3D point clouds (without an accurate laser plane equation, the intersection calculation will be completely distorted).

[0033] Finally, the calibration object point cloud is acquired, generating multi-view calibration object point cloud data. Specifically, the calibration object is fixed on a rotary table with its center aligned with the rotation axis. The rotation drive mechanism is controlled to rotate the camera to multiple angles, and the calibration object is photographed by the first and second cameras respectively. Based on the binocular camera reference parameter set, preliminary 3D reconstruction is performed on the images captured at each angle, obtaining multi-view point clouds of the calibration object under different cameras and angles. This unifies the independent coordinate systems of the first and second cameras into a global coordinate system fixed to the rotation axis, obtaining a precise transformation matrix. This solves the spatial alignment problem of multi-view data during rotation scanning, ensuring that point cloud data acquired from different angles and cameras can be fused under the same spatial reference, laying the spatial coordinate reference for subsequent point cloud fusion.

[0034] Step S2 primarily involves achieving precise and synchronous image acquisition of the cross-optical paths based on the calibration reference. Specifically, the two measurement optical paths are triggered sequentially with a half-interval at an angle.

[0035] In one embodiment, a global reference database is loaded into the synchronization control unit. After establishing communication connections between the rotary encoder, camera, laser, and synchronization control unit, the rotary drive mechanism is controlled to drive the rotary support and measuring unit to rotate uniformly around the rotation axis. The rotary encoder collects the rotation angle signal of the rotary drive mechanism in real time and transmits the angle data to the synchronization control unit in real time. The synchronization control unit compares the real-time angle data with a preset first trigger angle θ1. When the real-time angle reaches θ1, it generates and sends a first synchronization trigger command (including a second laser emission command and a first camera exposure acquisition command, with both commands issued simultaneously) to achieve precise triggering of the "opposite optical path," ensuring that the first image acquired by the first camera is the laser line image of its paired second laser, matching the design logic of the cross optical path. Furthermore, the synchronization control unit compares the real-time angle data with a preset second trigger angle θ2. When the real-time angle reaches θ2, it generates and sends a second synchronization trigger command (including a first laser emission command and a second camera exposure acquisition command, with both commands issued simultaneously) to complete the trigger acquisition of the two sets of cross optical paths, ensuring that the second image acquired by the second camera is the laser line image of its paired first laser.

[0036] The invention utilizes a rotary drive mechanism to rotate symmetrically arranged measurement units at a uniform speed, extending the "binocular laser line scanning" of this application to a surface scanning covering fan-shaped / conical regions. This meets the core requirement of "large-scale 3D measurement" in industrial settings and solves the field-of-view limitation of existing monocular line scanning technologies. Furthermore, regarding the core design of "cross-pairing of cameras and opposite lasers," a synchronous control unit receives angle signals from the rotary encoder and precisely triggers "opposite laser emission and camera exposure" at a specified angle. This ensures that the image acquired by each camera is a laser line image projected onto the object being measured by its paired laser. This is the core execution step for cross-optical path measurement, providing raw data for subsequent anti-occlusion point cloud reconstruction. Additionally, the precise triggering of the rotary encoder's angle positioning and synchronous control ensures that each acquired image carries accurate rotation angle information. This guarantees that point cloud data acquired from different angles can be accurately transformed to the global coordinate system based on the angle information, enabling continuous stitching of the rotated scan point cloud.

[0037] Step S3 mainly involves 3D reconstruction and fusion based on calibration parameters and acquired images, outputting an anti-occlusion, high-precision, and complete 3D point cloud.

[0038] In one embodiment, a first image preprocessing is performed to generate a first optimized laser line image. Specifically, distortion correction is applied to the first image based on the distortion coefficients of the first camera, followed by image processing operations such as filtering (eliminating ambient light and noise interference) and binarization (highlighting laser line features) to obtain the first optimized laser line image. The same preprocessing logic is then performed to obtain a second optimized laser line image.

[0039] Next, the Steger algorithm is used to extract the sub-pixel center coordinates (u, v) of the laser line in the first optimized image. Based on the intrinsic parameter matrix of the first camera, the pixel coordinates are back-projected into a spatial ray in the first camera coordinate system. The equations of this ray and the second laser plane are solved simultaneously to obtain the coordinates of the intersection points of the ray and the laser plane. All intersection point coordinates are integrated into a point cloud to obtain the first three-dimensional point cloud. The same solution logic is executed to obtain the second three-dimensional point cloud.

[0040] Finally, each spatial coordinate point in the first 3D point cloud is transformed using a transformation matrix, mapping it from the first camera coordinate system to a global coordinate system fixed to the rotation axis. The same transformation logic is then applied to map the second 3D point cloud to the global coordinate system. The two sets of global point clouds are then superimposed in the same global coordinate system, and fusion and deduplication algorithms such as voxel rasterization are used to obtain a fused and deduplicated intermediate 3D point cloud in the global coordinate system. This fused intermediate point cloud undergoes final spatial calibration and data verification, removing a small number of residual invalid points. The data is then encapsulated according to the standard format for industrial measurement to obtain the final complete 3D point cloud data in the global coordinate system.

[0041] Thus, by using the original image dataset and the global benchmark database as dual inputs, and through the entire process of image optimization, single-path reconstruction, coordinate unification, fusion deduplication, and result output, the complete transformation of optical image data into three-dimensional spatial point cloud data is achieved.

[0042] As can be seen, the symmetrical cross-type binocular laser rotation scanning 3D measurement method provided in this application adopts a symmetrical cross-type binocular dual-laser rotation scanning structure. Compared with the traditional monocular solution, it achieves a larger scanning field of view in a compact volume, covers a wider measurement area without significantly increasing the rotation angle, effectively reduces the motion envelope and the axial dimension of the equipment, and is more suitable for integrated use in space-constrained industrial scenarios. The cross-optical path design forms two independent and symmetrical measurement paths, possessing strong anti-occlusion capabilities, significantly reducing point cloud loss caused by structural occlusion of complex workpieces, and greatly improving the integrity and applicability of measurement data. Furthermore, the dual independent measurement data can be cross-checked, fused, and optimized, effectively eliminating noise and outliers, improving measurement accuracy and signal-to-noise ratio. Simultaneously, the long baseline binocular structure supports stereo matching and completion, further ensuring the reliability of the results.

[0043] Based on the same inventive concept, this application also provides a symmetrical cross-type binocular laser rotation scanning three-dimensional sensor. Since the principle of the system in this application is similar to the symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method described above, the implementation of the sensor can refer to the implementation of the method, and the repeated parts will not be described again.

[0044] Based on the same concept of the present invention, the specification is attached. Figure 4 As shown in the figure, an embodiment of this application provides the structure of an electronic device 400, which includes: at least one processor 401, at least one network interface 404 or other user interface 403, memory 405, and at least one communication bus 402. The communication bus 402 is used to realize the connection and communication between these components. The electronic device 400 may optionally include a user interface 403, including a display (e.g., touch screen, LCD, CRT, holographic imaging, or projector, etc.), a keyboard, or a clicking device (e.g., mouse, trackball, touchpad, or touch screen, etc.).

[0045] Memory 405 may include read-only memory and random access memory, and provides instructions and data to processor 401. A portion of memory 405 may also include non-volatile random access memory (NVRAM).

[0046] In some implementations, memory 405 stores elements that can protect modules or data structures, or subsets thereof, or extended sets thereof: The 4051 operating system contains various system programs used to implement various basic business functions and handle hardware-based tasks. Application module 4052 contains various applications, such as desktop (launcher), media player (MediaPlayer), browser (Browser), etc., to implement various application services.

[0047] In this embodiment of the application, by calling the program or instructions stored in the memory 405, the processor 401 is used to execute the steps of a symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method, which can realize a large field of view three-dimensional scanning in a compact volume, while greatly improving the sensor's anti-occlusion ability and ensuring the integrity of the measurement data.

[0048] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, performs steps such as those in a symmetrical cross-type binocular laser rotational scanning three-dimensional measurement method.

[0049] Specifically, the storage medium can be a general-purpose storage medium, such as a portable disk or hard disk. When the computer program on the storage medium is run, it can execute the above-mentioned symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method.

[0050] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and there may be other division methods in actual implementation. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the coupling or direct coupling or communication connection shown or discussed may be through some communication interface; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0051] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0052] In addition, the functional units in the embodiments provided in this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0053] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0054] Finally, it should be noted that the above embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application. All should be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method, characterized in that, An application is made to a symmetrical cross-type binocular laser rotation scanning 3D sensor, which includes a rotation drive mechanism, a rotation support, a first measurement unit, and a second measurement unit. The first and second measurement units are symmetrically distributed about the rotation axis of the rotation drive mechanism and fixed on the rotation support. The first measurement unit includes a first camera and a second laser located on the opposite side of its rotation axis, forming a first measurement optical path. The second measurement unit includes a second camera and a first laser located on the opposite side of its rotation axis, forming a second measurement optical path. The method includes the following steps: The internal parameters of the first camera and the second camera are calibrated respectively, as are the equations of the first laser plane of the first laser and the second laser plane of the second laser in the coordinate system of the first camera. The coordinate systems of the first camera and the second camera are then aligned with the global coordinate system fixed to the rotation axis. The rotation drive mechanism is activated, and rotation angle data is acquired in real time. When the object rotates to the first angle, the second laser is triggered to emit light and the first camera captures the first image of the object under test. When the object rotates to the second angle, the first laser is triggered to emit light and the second camera captures the second image of the object under test. Based on the first image and the equation of the second laser plane, the first three-dimensional point cloud is calculated using triangulation. Based on the second image and the equation of the first laser plane, the second three-dimensional point cloud is calculated using triangulation. The first and second three-dimensional point clouds are then transformed to the global coordinate system and fused and deduplicated sequentially to output the final three-dimensional point cloud.

2. The symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method according to claim 1, characterized in that, The process of calibrating the internal parameters of the first camera and the second camera, as well as the first laser plane equation of the first laser in the second camera coordinate system and the second laser plane equation of the second laser in the first camera coordinate system, includes the following steps: The first and second cameras are controlled to acquire multiple sets of calibration images of the checkerboard calibration board in different poses. The reference parameter sets of the first and second cameras are obtained through the camera calibration algorithm. The reference parameters include the intrinsic parameter matrix, distortion coefficients, and focal length. The laser line image on the target is acquired by the first measurement unit, and the target is moved to different positions for repeated acquisition. The sub-pixel center coordinates of the laser line in all images are extracted. Combined with the reference parameter set of the second camera and the world coordinate system equation of the target plane, the first laser plane equation of the first laser in the second camera coordinate system is obtained by fitting. Furthermore, the equation of the second laser plane of the second laser in the first camera coordinate system is obtained through the same calibration logic.

3. The symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method according to claim 2, characterized in that, The process of aligning the first camera coordinate system, the second camera coordinate system, and the global coordinate system fixed to the rotation axis includes the following steps: The calibration object is fixed on the rotary table and its center is aligned with the rotation axis. The rotation drive mechanism is controlled to rotate the camera to multiple angles, and the calibration object is photographed by the first camera and the second camera respectively. Preliminary 3D reconstruction is performed on images captured from various angles based on the reference parameter set of the binocular camera to obtain multi-view discrete point cloud data of the calibration object. Using the Iterative Closest Point (ICP) algorithm, all multi-view point clouds are aligned to a preset global coordinate system. By solving the coordinate transformation relationship through point cloud spatial matching, the transformation matrix from the first camera coordinate system to the world coordinate system and the transformation matrix from the second camera coordinate system to the world coordinate system are obtained.

4. The symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method according to claim 1, characterized in that, The rotary drive mechanism adopts a scanning strategy triggered at equal angular intervals. Each rotation of a fixed angle performs laser emission and image acquisition once, and multiple sets of data are acquired in a single rotation. Furthermore, the two measurement optical paths are triggered sequentially with half-intervals at different angles.

5. The symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method according to claim 1, characterized in that, The process of calculating the first three-dimensional point cloud based on the first image and the second laser plane equation using triangulation includes the following steps: After performing distortion correction on the first image based on the distortion coefficients of the first camera, image processing including filtering and binarization is performed to obtain the first optimized laser line image. The Steger algorithm is used to extract the sub-pixel center coordinates of the laser line in the first optimized image, and based on the intrinsic parameter matrix of the first camera, the sub-pixel center coordinates are back-projected into a spatial ray in the coordinate system of the first camera. Solve the equations of the spatial ray and the second laser plane simultaneously to obtain the coordinates of the intersection point of the ray and the laser plane, and integrate all the intersection point coordinates into the first three-dimensional point cloud.

6. The symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method according to claim 5, characterized in that, in, The first and second 3D point clouds are superimposed in the same global coordinate system, and fusion and deduplication are performed using algorithms such as voxel rasterization.

7. A symmetrical cross-type binocular laser rotation scanning three-dimensional sensor, characterized in that, The method includes a rotary drive mechanism, a rotary support, a first measurement unit, and a second measurement unit. The first and second measurement units are symmetrically distributed about the rotation axis of the rotary drive mechanism and fixed on the rotary support. The first measurement unit includes a first camera and a second laser located on the opposite side of its rotation axis, forming a first measurement optical path. The second measurement unit includes a second camera and a first laser located on the opposite side of its rotation axis, forming a second measurement optical path. The method is used to collaboratively implement the steps of the symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method as described in any one of claims 1 to 6.

8. A symmetrical cross-type binocular laser rotation scanning three-dimensional sensor according to claim 7, characterized in that, Also includes: A rotary encoder, connected to a rotary drive mechanism, is used to acquire rotation angle signals; The synchronization control unit is electrically connected to the rotary encoder, the first camera, the second camera, the first laser, and the second laser, respectively, and is used to control the triggering sequence of each camera and laser; and filters are also provided in front of the lenses of the first camera and the second camera.

9. An electronic device, characterized in that, include: The device includes a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. When the machine-readable instructions are executed by the processor, they perform the steps of the symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method as described in any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the steps of the symmetrical cross-type binocular laser rotation scanning three-dimensional measurement method as described in any one of claims 1 to 6.

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