A compact object three-dimensional detection system

Abstract

The application discloses a kind of compact object three-dimensional detection systems, belong to optical measurement technical field, including deflection reflection module, combined light splitting optical module, light emission module and receiver module, according to the reversibility of light, light beam emitted by light emission module can start from the right end of combined light splitting optical module, after light splitting, respectively projected on the object to be measured by plane mirror, then again deflected by other two plane mirrors and respectively entered into two receivers, or reversely, first deflected by two plane mirrors to generate light from light emission module to the object to be measured, then combined light at combined light splitting optical module by reverse travel, and entered into the right end of light receiver.The detection system provided by the application supports multiple working modes (such as forward light combination, reverse light splitting, etc.), enabling users to select the optimal working mode according to specific measurement scenarios, precision requirements and equipment conditions, thereby enhancing the practicability and functionality of the system.

Description

Technical Field

[0001] This invention relates to the field of optical inspection technology, and more specifically to a compact three-dimensional object inspection system. Background Technology

[0002] In modern industrial inspection, materials science, and precision manufacturing, high-precision and efficient non-contact measurement of the three-dimensional morphology, thickness, and surface shape of objects has become a core requirement. However, existing optical measurement systems, especially in scenarios requiring simultaneous measurement of both the top and bottom or front and back surfaces of an object, still have several problems. Traditional double-sided measurement methods often employ a time-division measurement strategy, measuring one surface first and then moving the object or equipment to measure the other. This approach is not only inefficient but also introduces cumulative errors due to equipment displacement, environmental changes, or time differences. Furthermore, when constructing a system using a beam splitter, unexpected mutual reflections between mirrors can easily occur, forming severe stray light. This stray light creates false contours on the imaging surface, mixing into the effective signal, significantly increasing data noise, and reducing the accuracy and reliability of the measurement results. In addition, existing calibration methods are usually cumbersome and lack dedicated tools and processes that can simultaneously and efficiently ensure the perpendicularity of the optical axis and the accuracy of the system transformation matrix.

[0003] Therefore, there is an urgent need in this field for a new detection system that can effectively suppress stray light, support simultaneous two-sided measurement, and has a certain degree of flexibility and configurability. Summary of the Invention

[0004] In view of this, the present invention provides a compact three-dimensional object detection system. Through optical path design, stray light interference generated within the system is fundamentally avoided, ensuring the acquisition of optical signals with a high signal-to-noise ratio. At the same time, the innovative spatial layout allows for a larger measurement area, enabling it to adapt to the measurement needs of objects of different sizes and shapes.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: On the one hand, the present invention provides a compact three-dimensional object detection system with anti-stray light, including: two light emitting modules, a deflection and reflection module, a beam combining and splitting optical module, a receiver module, and a processing module; The light emitting module is used to provide a light beam for the desired projection pattern; The deflection and reflection module is used to deflect the light beam emitted by the light emitting module onto the object under test, and to deflect the light beam reflected by the object under test into the beam combining and splitting optical module; The beam combining and splitting optical module is used to combine the beams reflected by the object under test and input them into the receiver module; The receiver module is used to receive the combined beam output by the beam combining and splitting optical module and generate image data; The processing module is used to analyze the image data to obtain comprehensive detection data of the three-dimensional morphology and surface quality of the object under test.

[0006] Preferably, the deflection and reflection module includes four plane mirrors. The first and second plane mirrors are used to deflect the light beams emitted from the two light emitting modules to the upper and lower surfaces of the object under test, respectively. The third and fourth plane mirrors are used to project the light beams reflected from the upper and lower surfaces of the object under test into the beam combining and splitting optical module, respectively.

[0007] Preferably, the detection system further includes a first calibration module and a second calibration module, wherein the first calibration module is used to perform single-system calibration on a single light emitting module and a single receiver module; and the second calibration module is used to perform dual-system calibration on the light emitting module and receiver module that have completed single-system calibration.

[0008] Preferably, the first calibration module includes a calibration plate, a stepped gauge block, a first control unit, an adjustment mechanism, and a first calculation unit; The calibration plate is placed below the light receiver via an adjustment mechanism; The first control unit is connected to the adjustment mechanism and the receiver module respectively, and is used to determine whether the optical axis of the receiver module is perpendicular to the calibration plate according to the calibration plate image obtained by the receiver module, and control the adjustment mechanism to make the receiver module perpendicular to the calibration plate. The first calculation unit is used to calculate the magnification of the light receiver based on the calibration plate image after the optical axis vertical calibration is completed; The first control unit is also connected to the light emitting module and is used to control the light emitting module to project a preset pattern; The stepped gauge block is placed on the object to be measured to modulate the preset pattern projected by the light emitting module; The first calculation unit is also used to establish geometric constraint equations and solve for calibration parameters based on the image coordinates of feature points in the modulated preset image, the displacement caused at different heights, the height difference of the stepped blocks, and the imaging magnification value.

[0009] Preferably, the second calibration module includes a standard gauge block, a second control unit, a preprocessing unit, and a second calculation unit; The standard gauge block is placed at the location of the object to be tested; The second control unit is connected to the light emitting module and the receiver module respectively, and is used to control the light emitting module to project the feature pattern and control the receiver to synchronously acquire image data; The preprocessing unit is used to obtain the correspondence between the image coordinates of the feature pattern and the feature signals based on the image data; The second calculation unit is used to construct a set of spatial relationship equations between the two light emitting modules and the receiver module based on the correspondence between image coordinates, feature signals and the thickness of the standard planar block, and to solve the set of spatial relationship equations to obtain the spatial position transformation parameters between the two single systems.

[0010] On the other hand, the present invention provides another compact three-dimensional object detection system, including: a light emitting module, a deflection and reflection module, a beam combining and splitting optical module, two receiver modules, and a processing module; The light emitting module is used to provide a light beam for the desired projection pattern; The beam combining and splitting optical module is used to split the beam of the light emitting module; The deflection and reflection module is used to deflect the beam emitted by the beam combining and splitting optical module onto the object under test, and to deflect the beam reflected by the object under test into the receiver module; The receiver module is used to receive the beam of light output by the deflection and reflection module and generate image data; The processing module is used to analyze the image data to obtain comprehensive detection data of the three-dimensional morphology and surface quality of the object under test.

[0011] Preferably, the deflection and reflection module includes four plane mirrors: the fifth and sixth plane mirrors are used to deflect the beam split by the beam combining and splitting optical module to the upper and lower surfaces of the object under test, respectively; the seventh and eighth plane mirrors are used to project the beams reflected from the upper and lower surfaces of the object under test to the receiver module, respectively.

[0012] Preferably, the detection system further includes a first calibration module and a second calibration module, wherein the first calibration module is used to perform single-system calibration on a single light emitting module and a single receiver module; and the second calibration module is used to perform dual-system calibration on the light emitting module and receiver module that have completed single-system calibration.

[0013] Preferably, the first calibration module includes a calibration plate, a stepped gauge block, a first control unit, an adjustment mechanism, and a first calculation unit; The calibration plate is placed below the light receiver via an adjustment mechanism; The first control unit is connected to the adjustment mechanism and the receiver module respectively, and is used to determine whether the optical axis of the receiver module is perpendicular to the calibration plate according to the calibration plate image obtained by the receiver module, and control the adjustment mechanism to make the receiver module perpendicular to the calibration plate. The first calculation unit is used to calculate the magnification of the light receiver based on the calibration plate image after the optical axis vertical calibration is completed; The first control unit is also connected to the light emitting module and is used to control the light emitting module to project a preset pattern; The stepped gauge block is placed on the object to be measured to modulate the preset pattern projected by the light emitting module; The first calculation unit is also used to establish geometric constraint equations and solve for calibration parameters based on the image coordinates of feature points in the modulated preset image, the displacement caused at different heights, the height difference of the stepped blocks, and the imaging magnification value.

[0014] Preferably, the second calibration module includes a standard gauge block, a second control unit, a preprocessing unit, and a second calculation unit; The standard gauge block is placed at the location of the object to be tested; The second control unit is connected to the light emitting module and the receiver module respectively, and is used to control the light emitting module to project the feature pattern and control the receiver to synchronously acquire image data; The preprocessing unit is used to obtain the correspondence between the image coordinates of the feature pattern and the feature signals based on the image data; The second calculation unit is used to construct a set of spatial relationship equations between the light emitting module and the two receiver modules based on the correspondence between image coordinates, feature signals and the thickness of the standard planar block, and to solve the set of spatial relationship equations to obtain the spatial position transformation parameters between the two single systems.

[0015] As can be seen from the above technical solution, compared with the prior art, this invention discloses a compact three-dimensional object detection system. Through an optical path design scheme, it fundamentally avoids stray light interference generated within the system, ensuring the acquisition of high signal-to-noise ratio optical signals. Simultaneously, it innovatively modifies the spatial layout, allowing for a larger measurement area to adapt to the measurement needs of objects of different sizes and shapes. Utilizing the principle of optical path reversibility, it designs a system supporting multiple working modes (such as forward beam combining and reverse beam splitting), enabling users to select the optimal working mode based on specific measurement scenarios, accuracy requirements, and equipment conditions, thereby enhancing the system's performance. The system is practical and functional, and the adjustable position and angle of the optical elements allow for indirect adjustment of the optical path and projection area. This enables the system to flexibly match light emitters and receivers with different parameters, optimize measurement performance, and improve the overall compatibility and adaptability of the system. It also provides a set of efficient and high-precision dedicated calibration methods and tools. Through an innovative optical axis vertical calibration process, it ensures the accuracy of the parameters and transformation relationships of the entire measurement system, laying the foundation for the final high-precision thickness and surface shape measurement. The overall structure can acquire data synchronously at one time, eliminating errors caused by time differences and ensuring a high degree of consistency and reliability of the measurement results. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a schematic diagram illustrating the image acquisition principle in the detection system of the present invention.

[0018] Figure 2 This is a front view of the calibration plate.

[0019] Figure 3 This is a view of the back of the calibration plate.

[0020] Figure 4 This is a schematic diagram of the stepped gauge blocks.

[0021] Figure 5 This is a schematic diagram of a standard gauge block. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention discloses a compact three-dimensional object detection system, such as... Figure 1 As shown, it includes: two light emitting modules, a deflection and reflection module, a beam combining and splitting optical module, a receiver module, and a processing module; The light emitting module is used to provide the light beam for the desired projection pattern; The deflection and reflection module is used to deflect the light beam emitted by the light emitting module onto the object under test, and to deflect the light beam reflected by the object under test into the beam combining and splitting optical module; The beam combining and splitting optical module is used to combine the beams reflected from the object under test and input them into the receiver module; The receiver module is used to receive the combined beam output by the beam combining and splitting optical module and generate image data; The processing module is used to analyze image data and obtain comprehensive detection data of the three-dimensional morphology and surface quality of the object under test. The comprehensive detection data of the three-dimensional morphology and surface quality of the object includes surface shape data, thickness data, texture data, defect analysis, etc.

[0024] Furthermore, the deflection and reflection module includes four plane mirrors. The first and second plane mirrors are used to deflect the light beams emitted from the two light emitting modules to the upper and lower surfaces of the object under test, respectively. The third and fourth plane mirrors are used to project the light beams reflected from the upper and lower surfaces of the object under test into the beam combining and splitting optical module, respectively.

[0025] Specifically, in this embodiment, the receiver module can be fixed in a detachable manner, and its position can be changed according to actual needs to realize the interchangeability of the two detection systems of the present invention. The beam splitting and combining optical module M3 is a beam splitting prism with a specific angle, which has bidirectional beam splitting and combining functions: it can split the incident beam from the right end into two independent optical paths, and it can also combine the two beams from the upper and lower planes into a parallel beam, which is output from the right end to receiving devices such as cameras.

[0026] The deflection and reflection module includes a series of plane mirrors M1 and M2. In this embodiment, the first plane mirror M2-1 deflects and reflects the light beam emitted by the light emitting module onto the upper surface of the object under test; the second plane mirror M2-2 reflects the light beam onto the lower surface of the object under test with symmetry or a specific geometric relationship. The plane mirror M1 is located between the object under test and the prism M3, and its installation angle has been comprehensively optimized to take into account both the size constraints of the prism M3 and the optical path requirements of the receiving device. The light reflected by M2 onto the surface of the object under test is collected and deflected onto the upper surface by the third plane mirror M1-1, and then collected and deflected onto the upper surface by the fourth plane mirror M1-2, and finally projected onto the corresponding incident surface of the prism M3. After light combining, the light enters the receiver module for signal acquisition.

[0027] Furthermore, the detection system of the present invention also includes a first calibration module and a second calibration module, wherein the first calibration module is used to perform single-system calibration on a single light emitting module and a single receiver module; the second calibration module is used to perform dual-system calibration on the light emitting module and receiver module that have completed single-system calibration. The first calibration module includes a calibration plate, stepped gauge blocks, a first control unit, an adjustment mechanism, and a first calculation unit; The calibration plate is placed below the light receiver via an adjustment mechanism; The first control unit is connected to the adjustment mechanism and the receiver module respectively, and is used to determine whether the optical axis of the receiver module is perpendicular to the calibration plate according to the calibration plate image obtained by the receiver module, and control the adjustment mechanism to make the receiver module perpendicular to the calibration plate. The first calculation unit is used to calculate the magnification of the light receiver based on the checkerboard image of the calibration board after the optical axis vertical calibration is completed. ; The first control unit is also connected to the light emitting module and is used to control the light emitting module to project a preset pattern; The stepped gauge block is placed on the object to be measured to modulate the preset pattern projected by the light emitting module; The computing unit is also used to establish geometric constraint equations based on the image coordinates of feature points in the preset image after step block modulation, and solve for the single-system calibration parameters, mainly including the angle between the optical axes of the light source projector and the receiver in the upper and lower single systems. And the angle between the receiver microarray (the camera's pixel array) and the plane containing the optical axis. The angle between the light source microarray (e.g., the micromirror array of a DLP) and the plane containing the optical axis. The distance between the optical axes of the light source projector and the receiver, or the equivalent distance. And the similarity ratio between the light source microarray unit and the receiver microarray unit. These parameters, or equivalent parameters, can be calibrated using publicly available binocular camera calibration methods.

[0028] Furthermore, the second calibration module includes a standard gauge block, a second control unit, a preprocessing unit, and a second calculation unit; The standard gauge block is placed at the location of the test object; the standard gauge block is placed at the location of the test object; the standard gauge block is as follows: Figure 5 As shown; the thickness of the standard gauge block is known, and the upper and lower surfaces are strictly parallel within the acceptable range of system error. Its thickness can be flexibly selected by the user in combination with the size of the object being measured, the system depth of field, and cost considerations.

[0029] The second control unit is connected to the light emitting module and the receiver module respectively, and is used to control the light emitting module to project the feature pattern and control the receiver to synchronously acquire image data; specifically, after the standard planar block is placed, the light emitting module is controlled to project the feature pattern so that the upper and lower surfaces of the block are simultaneously covered by the feature light image, and the receiver synchronously acquires the image.

[0030] The preprocessing unit is used to obtain the correspondence between the image coordinates of the feature pattern and the feature signals based on the image data; The second calculation unit is used to construct a set of spatial relationship equations between the two light emitting modules and the receiver module based on the correspondence between image coordinates, feature signals and the thickness of the standard planar block, and to solve the set of spatial relationship equations to obtain the spatial position transformation parameters between the two single systems.

[0031] The specific calibration method is as follows: let the single systems corresponding to the upper and lower surfaces be A and B, respectively, which differ by a coordinate system rotation transformation R and a translation transformation T. Therefore...

[0032] in, The three-dimensional coordinates of a point on the lower surface measured by system B. In system A, the corresponding coordinates are represented by R, a three-dimensional rotation matrix that can be determined by Euler angles, etc., and contains three angular variables. As a constant translation vector, it contains three constants, thus there are a total of 6 spatial position transformation parameters between the two single systems.

[0033] By utilizing the characteristics of the upper and lower surfaces of the standard gauge block, the corresponding plane normal vector is determined through relevant data measured by systems A and B. Combined with multiple sets of linearly independent normal vectors, the calibration of parameters related to rotation transformation is completed. At the same time, calibration error is reduced through multiple sets of measurements.

[0034] Based on the known thickness of the standard gauge block, and combined with the relevant data of the upper and lower surfaces measured by the system, the calibration of the translation transformation parameters is completed through the corresponding correlation, and finally the accurate calibration of system A and B is achieved.

[0035] This invention is not limited to the above methods for determining the spatial position transfer parameters between two systems; other methods for calculating spatial position transfer parameters based on the thickness measurement principle of this invention are also acceptable.

[0036] On the other hand, based on the reversibility of light, the present invention provides another compact three-dimensional object detection system, which can be launched from the right end of prism M3, split into beams, and then projected onto the object to be measured through M1-1 and M1-2 respectively. After being deflected by M2-1 and M2-2, the beams are then sent to two receivers. The system includes: a light emission module, a deflection and reflection module, a beam combining and splitting optical module, two receiver modules, and a processing module. The light-emitting module is used to provide the required light beam; The beam combining and splitting optical module is used to split the beam of the light emitting module; The deflection and reflection module is used to deflect the beam emitted by the beam combining and splitting optical module onto the object under test, and to deflect the beam reflected by the object under test into the receiver module; The receiver module is used to receive the beam output by the deflection and reflection module and generate image data; The processing module is used to analyze image data and obtain comprehensive detection data of the three-dimensional morphology and surface quality of the object under test. The comprehensive detection data of the three-dimensional morphology and surface quality of the object includes surface shape data, thickness data, texture data, defect analysis, etc.

[0037] Furthermore, the deflection and reflection module includes four plane mirrors. The fifth and sixth plane mirrors are used to deflect the beam split by the beam combining and splitting optical module to the upper and lower surfaces of the object under test, respectively. The seventh and eighth plane mirrors are used to project the beams reflected from the upper and lower surfaces of the object under test to the receiver module, respectively.

[0038] Furthermore, the detection system of the present invention also includes a first calibration module and a second calibration module, wherein the first calibration module is used to perform single-system calibration on a single light emitting module and a single receiver module; the second calibration module is used to perform dual-system calibration on the light emitting module and receiver module that have completed single-system calibration. The first calibration module includes a calibration plate, stepped gauge blocks, a first control unit, an adjustment mechanism, and a first calculation unit; The calibration plate is placed below the light receiver via an adjustment mechanism; The first control unit is connected to the adjustment mechanism and the receiver module respectively, and is used to determine whether the optical axis of the receiver module is perpendicular to the calibration plate according to the calibration plate image obtained by the receiver module, and control the adjustment mechanism to make the receiver module perpendicular to the calibration plate. The first calculation unit is used to calculate the magnification of the light receiver based on the checkerboard image of the calibration board after the optical axis vertical calibration is completed. ; The first control unit is also connected to the light emitting module and is used to control the light emitting module to project a preset pattern; The stepped gauge block is placed on the object to be measured to modulate the preset pattern projected by the light emitting module; The computing unit is also used to establish geometric constraint equations based on the image coordinates of feature points in the preset image after step block modulation, and solve for the single-system calibration parameters, mainly including the angle between the optical axes of the light source projector and the receiver in the upper and lower single systems. And the angle between the receiver microarray (the camera's pixel array) and the plane containing the optical axis. The angle between the light source microarray (e.g., the micromirror array of a DLP) and the plane containing the optical axis. The distance between the optical axes of the light source projector and the receiver, or the equivalent distance. And the similarity ratio between the light source microarray unit and the receiver microarray unit. These parameters, or equivalent parameters, can be calibrated using publicly available binocular camera calibration methods.

[0039] Furthermore, the second calibration module includes a standard gauge block, a second control unit, a preprocessing unit, and a second calculation unit; The standard gauge block is placed at the location of the test object; the standard gauge block is placed at the location of the test object; the standard gauge block is as follows: Figure 5 As shown; the thickness of the standard gauge block is known, and the upper and lower surfaces are strictly parallel within the acceptable range of system error. Its thickness can be flexibly selected by the user in combination with the size of the object being measured, the system depth of field, and cost considerations.

[0040] The second control unit is connected to the light emitting module and the receiver module respectively, and is used to control the light emitting module to project the feature pattern and control the receiver to synchronously acquire image data; specifically, after the standard planar block is placed, the light emitting module is controlled to project the feature pattern so that the upper and lower surfaces of the block are simultaneously covered by the feature light image, and the receiver synchronously acquires the image.

[0041] The preprocessing unit is used to obtain the correspondence between the image coordinates of the feature pattern and the feature signals based on the image data; The second calculation unit is used to construct a set of spatial relationship equations between the two light emitting modules and the receiver module based on the correspondence between image coordinates, feature signals and the thickness of the standard planar block, and to solve the set of spatial relationship equations to obtain the spatial position transformation parameters between the two single systems.

[0042] The specific calibration method is as follows: let the single systems corresponding to the upper and lower surfaces be A and B, respectively, which differ by a coordinate system rotation transformation R and a translation transformation T. Therefore...

[0043] in, The three-dimensional coordinates of a point on the lower surface measured by system B. In system A, the corresponding coordinates are represented by R, a three-dimensional rotation matrix that can be determined by Euler angles, etc., and contains three angular variables. As a constant translation vector, it contains three constants, thus there are a total of 6 spatial position transformation parameters between the two single systems.

[0044] By utilizing the characteristics of the upper and lower surfaces of the standard gauge block, the corresponding plane normal vector is determined through relevant data measured by systems A and B. Combined with multiple sets of linearly independent normal vectors, the calibration of parameters related to rotation transformation is completed. At the same time, calibration error is reduced through multiple sets of measurements.

[0045] Based on the known thickness of the standard gauge block, and combined with the relevant data of the upper and lower surfaces measured by the system, the calibration of the translation transformation parameters is completed through the corresponding correlation, and finally the accurate calibration of system A and B is achieved.

[0046] This invention is not limited to the above methods for determining the spatial position transfer parameters between two systems; other methods for calculating spatial position transfer parameters based on the thickness measurement principle of this invention are also acceptable.

[0047] like Figure 2 and Figure 3 As shown, the four corner areas of the calibration plate are printed with a standard checkerboard pattern, and the physical distance between each corner point is known through precision machining; the central area is etched with cross lines, and the bottom is coated with a uniform semi-transparent and semi-reflective film with an appropriate transmittance-to-reflection ratio within the light source band of the calibration plate.

[0048] In this embodiment, the specific calibration steps are as follows: First, the calibration plate is placed on a mechanism that allows for precise adjustment of tilt and displacement. A light receiver is positioned above it. The optical axis of the light receiver is determined by whether the crosshairs reflected from the bottom reflective film of the calibration plate coincide with the image of the crosshairs etched above it in the receiver. This determines whether the optical axis of the light receiver is precisely perpendicular to the plane of the calibration plate. Feedback is then used to control the adjustment mechanism, ultimately ensuring that the light receiver is precisely perpendicular to the plane of the calibration plate. After completing the optical axis vertical calibration, a complete and clear image of the calibration plate is acquired. Using mature image processing algorithms (such as Harris corner detection or sub-pixel extraction methods), the pixel coordinates of all the inner corner points of the checkerboard pattern are calculated, combined with the known physical distances between the corner points. and corner pixel distance The imaging magnification of this subsystem can be calculated based on the definition.

[0049] in The pixel size of the receiver imaging microarray.

[0050] Then, using, for example Figure 4 The dedicated stepped gauge block shown is used to determine the spatial relationship between the light emitting module and the receiver. The upper plane of the gauge block is machined with high precision, and a groove of known depth is precisely machined in the middle. The surface of the groove is strictly parallel to the upper surface of the gauge block. The corresponding calibration procedure is as follows: Operate the light-emitting module to project a specific pattern, such as a dot matrix pattern, ensuring that the projection area covers planes at different depths on the gauge block. The receiver synchronously acquires the image modulated by the gauge block surface. Using the image coordinates of feature points in the image, their displacement at different heights, the known height difference, and the calculated system magnification, establish the corresponding geometric constraint equations. Solve these equations to obtain the complete calibration parameters of the subsystem.

[0051] The specific process of thickness measurement and surface shape detection performed by the processing module in the detection system provided by this invention is as follows: Thickness measurement: Based on existing 3D optical measurement technology, and by combining light rays projected onto different surfaces of the object under test, the 3D topography of two different surfaces of the object can be reconstructed separately. Through system calibration, the spatial relationship between the upper and lower surfaces can be determined. Then, by combining the reconstructed data of the two surfaces with the calibration parameters, precise data stitching and fusion can be achieved, and the object's thickness can be calculated using conventional data measurement and processing methods.

[0052] Surface shape detection: Based on the results of 3D reconstruction, the top and bottom surface morphology data of the object are acquired. Point clouds can be processed through plane fitting, curvature analysis, outlier identification and removal, thereby achieving surface shape detection. Furthermore, by projecting light spots or structured light patterns of different shapes, colors, and brightness through a light emitter, the receiver can acquire image information (including patterns, colors, surface textures, etc.) of the top and bottom surfaces of the object under test. All this data is acquired synchronously at the same time point and under the same measurement reference, overcoming the technical bottlenecks of traditional step-by-step, asynchronous, and large cumulative errors. This eliminates errors caused by time differences, ensuring high consistency and reliability of the measurement results. Using this image information, combined with commonly used 2D image and 3D point cloud detection and processing algorithms, synchronous surface shape detection and defect analysis of different surfaces of an object can be achieved.

[0053] This invention employs a spatially staggered arrangement between M1, M2, and the object under test, allowing effective imaging light rays from diffuse reflection on the object's surface to enter the subsequent optical path via M1. This design, through its physical structure and the principle of diffuse reflection, blocks the direct stray light path formed by specular reflection between M1 and M2. This effectively avoids stray light that may occur during light propagation between M1 and M2, and also prevents the superposition of the M2 contour (or vice versa) and other external interference contours within M1. This mechanism effectively suppresses the aforementioned phenomena, significantly reduces noise interference in the acquired data, and improves the signal-to-noise ratio and data reliability.

[0054] In addition, the spatial distribution of each component in this solution provides relatively large space areas at the left end and both ends of the measured surface, which can accommodate the measurement of objects of different sizes and shapes, expand the applicable range of the measurement system, and improve the flexibility of equipment configuration and use.

[0055] Furthermore, this solution offers a novel approach: leveraging the reversibility of light, light can originate from the right end of prism M3, be split, and then projected onto the object under test via M1-1 and M1-2. After deflection by M2-1 and M2-2, the light then enters two receivers. Alternatively, light can be generated in the reverse direction by the light-emitting modules at both ends of M2-1 and M2-2, reversed, and then combined at prism M3 before entering the light receiver on the right. Users can flexibly choose the optimal configuration based on the measurement scenario, accuracy requirements, and cost budget. Moreover, the positions and angles of M1, M2, and M3 can be adjusted as needed. Adjusting their positions can indirectly lengthen or shorten the optical path between the transmitter and the object to the receiver, adapting to different depths of field and resolution imaging requirements. Adjusting their angles can change the illumination area projected onto the measured surface, altering the size and position of the measurement area. This design allows the system to flexibly match light sources and detectors with different performance parameters, achieving optimized system performance.

[0056] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0057] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A compact three-dimensional object detection system, characterized in that, include: Two light emitting modules, a deflection and reflection module, a beam combining and splitting optical module, a receiver module, and a processing module; The light emitting module is used to provide a light beam for the desired projection pattern; The deflection and reflection module is used to deflect the light beam emitted by the light emitting module onto the object under test, and to deflect the light beam reflected by the object under test into the beam combining and splitting optical module; The beam combining and splitting optical module is used to combine the beams reflected by the object under test and input them into the receiver module; The receiver module is used to receive the combined beam output by the beam combining and splitting optical module and generate image data; The processing module is used to analyze the image data to obtain comprehensive detection data of the three-dimensional morphology and surface quality of the object under test.

2. The compact three-dimensional object detection system according to claim 1, characterized in that, The deflection and reflection module includes four plane mirrors. The first and second plane mirrors are used to deflect the light beams emitted from the two light emitting modules to the upper and lower surfaces of the object under test, respectively. The third and fourth plane mirrors are used to project the light beams reflected from the upper and lower surfaces of the object under test into the beam combining and splitting optical module, respectively.

3. The compact three-dimensional object detection system according to claim 1, characterized in that, The detection system further includes a first calibration module and a second calibration module, wherein the first calibration module is used to perform single-system calibration on a single light emitting module and a single receiver module; and the second calibration module is used to perform dual-system calibration on the light emitting module and receiver module that have completed single-system calibration.

4. A compact three-dimensional object detection system according to claim 3, characterized in that, The first calibration module includes a calibration plate, a stepped gauge block, a first control unit, an adjustment mechanism, and a first calculation unit; The calibration plate is placed below the light receiver via an adjustment mechanism; The first control unit is connected to the adjustment mechanism and the receiver module respectively, and is used to determine whether the optical axis of the receiver module is perpendicular to the calibration plate according to the calibration plate image obtained by the receiver module, and control the adjustment mechanism to make the receiver module perpendicular to the calibration plate. The first calculation unit is used to calculate the magnification of the light receiver based on the calibration plate image after the optical axis vertical calibration is completed; The first control unit is also connected to the light emitting module and is used to control the light emitting module to project a preset pattern; The stepped gauge block is placed on the object to be measured to modulate the preset pattern projected by the light emitting module; The first calculation unit is also used to establish geometric constraint equations and solve for calibration parameters based on the image coordinates of feature points in the modulated preset image, the displacement caused at different heights, the height difference of the stepped blocks, and the imaging magnification value.

5. A compact three-dimensional object detection system according to claim 3, characterized in that, The second calibration module includes a standard gauge block, a second control unit, a preprocessing unit, and a second calculation unit; The standard gauge block is placed at the location of the object to be tested; The second control unit is connected to the light emitting module and the receiver module respectively, and is used to control the light emitting module to project the feature pattern and control the receiver to synchronously acquire image data; The preprocessing unit is used to obtain the correspondence between the image coordinates of the feature pattern and the feature signals based on the image data; The second calculation unit is used to construct a set of spatial relationship equations between the two light emitting modules and the receiver module based on the correspondence between image coordinates, feature signals and the thickness of the standard planar block, and to solve the set of spatial relationship equations to obtain the spatial position transformation parameters between the two single systems.

6. A compact three-dimensional object detection system, characterized in that, include: Light emitting module, deflection and reflection module, beam combining and splitting optical module, two receiver modules, and processing module; The light emitting module is used to provide a light beam for the desired projection pattern; The beam combining and splitting optical module is used to split the beam of the light emitting module; The deflection and reflection module is used to deflect the beam emitted by the beam combining and splitting optical module onto the object under test, and to deflect the beam reflected by the object under test into the receiver module; The receiver module is used to receive the beam of light output by the deflection and reflection module and generate image data; The processing module is used to analyze the image data to obtain comprehensive detection data of the three-dimensional morphology and surface quality of the object under test.

7. A compact three-dimensional object detection system according to claim 6, characterized in that, The deflection and reflection module includes four plane mirrors. The fifth and sixth plane mirrors are used to deflect the beam split by the beam combining and splitting optical module to the upper and lower surfaces of the object under test, respectively. The seventh and eighth plane mirrors are used to project the beams reflected from the upper and lower surfaces of the object under test to the receiver module, respectively.

8. A compact three-dimensional object detection system according to claim 6, characterized in that, The detection system further includes a first calibration module and a second calibration module, wherein the first calibration module is used to perform single-system calibration on a single light emitting module and a single receiver module; and the second calibration module is used to perform dual-system calibration on the light emitting module and receiver module that have completed single-system calibration.

9. A compact three-dimensional object detection system according to claim 8, characterized in that, The first calibration module includes a calibration plate, a stepped gauge block, a first control unit, an adjustment mechanism, and a first calculation unit; The calibration plate is placed below the light receiver via an adjustment mechanism; The first control unit is connected to the adjustment mechanism and the receiver module respectively, and is used to determine whether the optical axis of the receiver module is perpendicular to the calibration plate according to the calibration plate image obtained by the receiver module, and control the adjustment mechanism to make the receiver module perpendicular to the calibration plate. The first calculation unit is used to calculate the magnification of the light receiver based on the calibration plate image after the optical axis vertical calibration is completed; The first control unit is also connected to the light emitting module and is used to control the light emitting module to project a preset pattern; The stepped gauge block is placed on the object to be measured to modulate the preset pattern projected by the light emitting module; The first calculation unit is also used to establish geometric constraint equations and solve for calibration parameters based on the image coordinates of feature points in the modulated preset image, the displacement caused at different heights, the height difference of the stepped blocks, and the imaging magnification value.

10. A compact three-dimensional object detection system according to claim 8, characterized in that, The second calibration module includes a standard gauge block, a second control unit, a preprocessing unit, and a second calculation unit; The standard gauge block is placed at the location of the object to be tested; The second control unit is connected to the light emitting module and the receiver module respectively, and is used to control the light emitting module to project the feature pattern and control the receiver to synchronously acquire image data; The preprocessing unit is used to obtain the correspondence between the image coordinates of the feature pattern and the feature signals based on the image data; The second calculation unit is used to construct a set of spatial relationship equations between the light emitting module and the two receiver modules based on the correspondence between image coordinates, feature signals and the thickness of the standard planar block, and to solve the set of spatial relationship equations to obtain the spatial position transformation parameters between the two single systems.

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