A method and apparatus for three-dimensional scanning of a ring-shaped large-aperture spherical optical element

Abstract

This application provides a method and apparatus for three-dimensional scanning of a ring-shaped large-aperture spherical optical element, belonging to the field of optical element scanning technology. The method includes: determining multiple ring-shaped scanning regions on the large-aperture spherical optical element based on the central spatial position of the element and the scanning sub-aperture size parameters; traversing each ring-shaped scanning region to complete a three-dimensional scan of the large-aperture spherical optical element; for each ring-shaped scanning region, scanning is performed through multiple sub-apertures; when scanning the current ring-shaped scanning region, the spatial coordinates of the current sub-aperture are calculated based on the position information of the current ring-shaped scanning region, and the current sub-aperture is scanned based on the spatial coordinates. The ring-shaped large-aperture spherical optical element three-dimensional scanning method and apparatus provided in this application are used to achieve rapid full-aperture scanning of the optical element surface.

Description

Technical Field

[0001] This application relates to the field of optical element scanning technology, and in particular to a three-dimensional scanning method and apparatus for a ring-shaped large-aperture spherical optical element. Background Technology

[0002] With the ever-increasing performance requirements of optical systems, ultra-precision large-aperture spherical optical components, such as spherical / aspherical optical components, are increasingly widely used in cutting-edge applications such as high-energy laser devices and the IC field. However, due to limitations in current processing technology, various defects are inevitably introduced during key manufacturing processes such as cutting, grinding, and polishing, which can seriously affect the normal operation and service life of the system. Therefore, detecting surface defects in high-precision optical components is of great significance for effectively controlling surface defects, improving the quality of optical components, and assisting in the optimization of component manufacturing processes.

[0003] Current scanning and inspection of large-aperture optical components generally involves dividing the component surface into multiple small sub-regions, acquiring sub-aperture images one by one, and then stitching them together to form full-aperture information. This addresses the issue that a single imaging field of view cannot cover a large-aperture component. Among these methods, sub-aperture scanning technology for planar components is relatively mature, often using a two-dimensional displacement stage to achieve grid-like path planning. However, for spherical components, existing solutions employ a five-axis displacement platform, adjusting the posture of the component or inspection lens by rotating and tilting it to achieve imaging of each sub-aperture on the spherical surface. While the five-axis displacement platform solution can adapt to spherical posture adjustment, it requires multi-axis coordinated control, resulting in complex mechanical structure design, high assembly and adjustment difficulty, and the multi-axis motion can easily introduce cumulative errors, affecting the sub-aperture stitching accuracy. It also increases equipment and maintenance costs. Summary of the Invention

[0004] In view of this, this application provides a three-dimensional scanning method and apparatus for a ring-shaped large-aperture spherical optical element, which can realize rapid and accurate full-aperture scanning of the surface of the optical element.

[0005] Specifically, this application is implemented through the following technical solution:

[0006] The first aspect of this application provides a three-dimensional scanning method for a ring-shaped large-aperture spherical optical element, the method comprising:

[0007] Install the large-aperture spherical optical element;

[0008] Based on the central spatial position and scanning sub-aperture size parameters of the large-aperture spherical optical element, multiple annular scanning areas are determined on the large-aperture spherical optical element; wherein, all annular scanning areas are ring-shaped areas with the central spatial position as the center, and the combined annular scanning areas cover the surface to be scanned of the large-aperture spherical optical element;

[0009] The three-dimensional scan of the large-aperture spherical optical element is completed by traversing each of the aforementioned annular scanning areas.

[0010] Specifically, for each of the annular scanning regions, scanning is performed using multiple sub-apertures. When scanning the current annular scanning region, the spatial coordinates of the current sub-aperture are calculated based on the position information of the current annular scanning region, and the current sub-aperture is scanned based on the spatial coordinates.

[0011] A second aspect of this application provides a three-dimensional scanning device for a ring-shaped large-aperture spherical optical element, the device comprising a mounting module, a calculation module, and a scanning module; wherein...

[0012] The mounting module is used to mount the large-aperture spherical optical element;

[0013] The calculation module is used to determine multiple annular scanning regions on the large-aperture spherical optical element based on the central spatial position and scanning sub-aperture size parameters of the large-aperture spherical optical element; wherein, all annular scanning regions are ring-shaped regions with the central spatial position as the center, and the combination of all annular scanning regions covers the surface to be scanned of the large-aperture spherical optical element;

[0014] The scanning module is used to traverse each of the annular scanning areas to complete the three-dimensional scanning of the large-aperture spherical optical element;

[0015] Specifically, for each of the annular scanning regions, scanning is performed using multiple sub-apertures. When scanning the current annular scanning region, the spatial coordinates of the current sub-aperture are calculated based on the position information of the current annular scanning region, and the current sub-aperture is scanned based on the spatial coordinates.

[0016] The three-dimensional scanning method and apparatus for large-aperture spherical optical elements provided in this application can achieve rapid and accurate three-dimensional scanning of the surface of large-aperture optical elements while ensuring full aperture coverage, and can also take into account the integrity, accuracy and efficiency of the detection. Specifically, based on the central spatial position of the large-aperture spherical optical element, the surface to be scanned is divided into multiple concentric ring-shaped scanning areas, ensuring that the element surface is covered without omission after all areas are combined. This solves the problem of edge omission or repeated scanning caused by unreasonable area division in traditional scanning, thus ensuring the integrity of the detection. In addition, the entire scanning process does not rely on complex multi-axis motion mechanisms, but can be completed by only traversing the ring area and accurately focusing on the sub-aperture, which greatly simplifies the operation process, effectively shortens the scanning time, and achieves high-efficiency detection. Attached Figure Description

[0017] Figure 1 A flowchart of an embodiment of the three-dimensional scanning method for a large-aperture spherical optical element in the form of a ring provided in this application;

[0018] Figure 2 A schematic diagram of the detection system shown as an exemplary embodiment of this application;

[0019] Figure 3 This is a schematic diagram of the structure of Embodiment 2 of the three-dimensional scanning device for a ring-shaped large-aperture spherical optical element provided in this application.

[0020] Explanation of reference numerals in the attached figures:

[0021] 1: Light source;

[0022] 2: Multiple spectral confocal sensors;

[0023] 3: Large-aperture spherical optical elements;

[0024] 4: Large-aperture spherical optical element plane;

[0025] 5: X-axis displacement stage;

[0026] 6: Displacement stage in the YZ direction. Detailed Implementation

[0027] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0028] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used herein are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0029] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0030] The following specific embodiments are given to illustrate the technical solution of this application in detail.

[0031] Figure 1This is a flowchart of an embodiment of the three-dimensional scanning method for a ring-shaped large-aperture spherical optical element provided in this application. Please refer to... Figure 1 The method provided in this embodiment may include:

[0032] S101. Install the large-aperture spherical optical element.

[0033] Optionally, the large-aperture spherical optical element is vertically mounted on the sample stage, the sample stage is mounted on a three-dimensional displacement stage, the optical axis of the large-aperture spherical optical element is parallel to the horizontal plane, multiple spectral confocal sensors are fixed on the same side as the illumination source, the range of the multiple spectral confocal sensors is determined according to the working distance of the detection elements of the multiple spectral confocal sensors, and the surface to be scanned of the large-aperture spherical optical element faces the imaging direction of the detection system.

[0034] Specifically, Figure 2 A schematic diagram of the detection system shown as an exemplary embodiment of this application is provided below. Figure 2 An optical element with a flat back and a convex spherical front, and a diameter of 100mm, is vertically fixed on the sample stage. The sample stage is fixed on the X-axis displacement stage 5. During loading, the optical axis of the sample is kept as parallel as possible to the horizontal plane. The light source emitted by the illumination source 1 faces the spherical surface 3 of the large-aperture spherical optical element. Multiple spectral confocal sensors 2 are fixed to one side of the illumination source 1. During installation, the working distance of the probe is ensured to be within the range of the sensor. The probe and sensors are both mounted on the displacement stage 6 in the YZ direction. The three-dimensional displacement stage used is a large-stroke, high-precision three-dimensional displacement stage with a positioning accuracy of ±5μm. The spectral confocal sensor has a range of 16.8mm and a resolution of up to 0.2μm. The maximum object-side field of view of the data acquisition unit is 15mm×12mm, and the size of its individual sub-apertures can be set through the software analysis unit. The depth of field of the detection system is ±0.5mm.

[0035] A large-aperture spherical optical element is mounted on the sample stage using a clamping mechanism. The sample stage is mounted on an X-axis displacement stage. The illumination source, detection system, and data acquisition unit are all fixed on the Y and Z axes. The position of the large-aperture spherical optical element relative to the detection system is adjusted by combining the mutually perpendicular X and Y axes, while the Z axis is parallel to the optical axis of the optical element, supporting the axial translation of the spectral confocal sensor within the working distance range. The X and Y axes of the displacement stage are perpendicular to the optical axis of the optical element. The X-axis displacement stage supports the lateral translation of the sample, while the Y-axis displacement stage supports the vertical translation of the probe. The coordinated movement of the X and Y axes adjusts the spatial position between the sample and the probe. The Z axis is parallel to the optical axis of the optical element, supporting the axial translation of the probe and sensor, ensuring that the data acquisition unit acquires a clear image.

[0036] S102. Based on the central spatial position and scanning sub-aperture size parameters of the large-aperture spherical optical element, determine multiple annular scanning areas on the large-aperture spherical optical element; wherein, all annular scanning areas are ring-shaped areas with the central spatial position as the center, and the combination of all annular scanning areas covers the surface to be scanned of the large-aperture spherical optical element.

[0037] Specifically, multiple rectangularly distributed spectral confocal sensors are used to simultaneously acquire the relative distances between four sampling points on the surface of the component and the sensors; based on the spatial coordinate system constructed by the displacement stage, the relative distances are converted into three-dimensional coordinates of the four sampling points; the spherical contour of the component is fitted by a centering algorithm, and the projection points of the optical axis on the XY plane are calculated according to the contour geometry, and the central spatial position is determined by combining the Z-axis direction reference.

[0038] Furthermore, the width of the overlapping area between adjacent annular scanning areas is a first width, which is directly proportional to the diameter of the scanning sub-aperture and directly proportional to the center distance between adjacent scanning sub-apertures within the same annular scanning area. The step of traversing each annular scanning area to complete the three-dimensional scanning of the large-aperture spherical optical element includes:

[0039] (1) Determine the starting and ending points of the current circular scanning area;

[0040] Specifically, the spatial coordinates of the center of the large-aperture spherical optical element obtained by the centering algorithm are used as a reference. Combined with the serial number of the current annular scanning area and the side length of a single sub-aperture, the inner radius and outer radius of the current annular scanning area are calculated. The radial range of the current annular scanning area in the XY plane is determined based on the inner radius and the outer radius. The center spatial position is taken as the scanning start point, and the position counterclockwise from the scanning start point, with a distance less than the diameter of the sub-aperture, is taken as the scanning end point. This can completely cover the circumferential range of the annular area. The end point position can form a circumferential closed loop with the starting point position, avoiding circumferential scanning gaps. At the same time, the radial boundary is clearly defined by the calculation of the inner and outer radii, which can ensure that the start point and the end point are both within the radial range of the current annular area and do not exceed the area boundary, resulting in coordinate misalignment. (2) Starting from the scanning start point, the current annular scanning area is scanned based on the sub-aperture until the scanning end point is reached. The distance between the centers of adjacent sub-apertures in the same annular scanning area is less than the diameter of the sub-aperture. The distance between the two closest sub-apertures in adjacent annular scanning areas is less than the diameter of the sub-aperture.

[0041] Specifically, starting from the scanning origin, the current annular scanning area is scanned clockwise based on the sub-apertures. During the scanning process, the spacing between adjacent sub-apertures within the same annular scanning area is controlled to be less than the sub-aperture diameter. This allows adjacent sub-apertures to form overlapping areas in the XY plane. Due to the curvature of the spherical element, continuous circumferential distribution alone cannot completely cover the radial range. The overlapping design ensures that each radial position on the sphere is covered by at least one sub-aperture. Controlling the spacing between the nearest sub-apertures between adjacent annular areas to be less than the sub-aperture diameter is because the annular area expands in a stepped manner from the inside to the outside. The sub-apertures of the inner and outer annular rings need to connect radially. The overlapping design avoids radial scanning gaps between annular areas. The overlapping coverage network formed by controlling the sub-aperture spacing completely eliminates scanning blind spots on the surface of the spherical element, ensuring that defects across the entire aperture range can be detected and improving scanning integrity.

[0042] (3) Determine the next unscanned annular scanning region adjacent to the current annular scanning region, determine the target sub-aperture closest to the scanning endpoint in the next annular scanning region, and use the target sub-aperture as the starting sub-aperture of the next annular scanning region.

[0043] Specifically, the XY coordinates of the current annular scanning area's endpoint are extracted, the XY coordinates of all sub-apertures in the next annular area are calculated, and the Euclidean distance formula is used to calculate the distance between the XY coordinates of the scanning endpoint and the coordinates of each sub-aperture in the next annular area. The sub-aperture with the smallest distance is selected as the target sub-aperture, and the center position of the target sub-aperture is set as the starting point sub-aperture of the next annular scanning area, thus completing the starting point positioning for area switching.

[0044] This ensures that all annular regions are covered radially in sequence, avoiding region duplication or omission. Calculating the distance between the current endpoint and the next region's sub-aperture to determine the starting point is crucial because the current endpoint is the circumferential end position of the current region. Selecting the nearest sub-aperture as the starting point minimizes the stage movement distance between the two regions. Simultaneously, the target sub-aperture is within the radial range of the next region, meeting the scanning boundary requirements of the next region, and can be directly used as the starting point to initiate scanning. Selecting the nearest sub-aperture as the starting point of the next region, compared to randomly selecting a starting point, reduces region switching time and significantly improves overall scanning efficiency.

[0045] Furthermore, for the surface to be scanned of the spherical optical element, which has a three-dimensional spatial shape, this application employs multiple concentric annular regions for scanning to accelerate the scanning process. Different annular scanning regions are not on the same horizontal plane, but the centers of all annular scanning regions are on the same vertical axis, i.e., the multiple annular scanning regions are arranged in a stepped shape. The inner and outer radii of the first annular scanning region are determined. The inner radius of the first region starts from the center position, which is 0, and the outer radius is equal to 0.8 to 1 times the side length of the sub-aperture. This ensures that at least one complete scanning sub-aperture can be accommodated within the region, while reserving overlap space for adjacent regions. The inner radius of each subsequent region is equal to the outer radius of the previous region, and the outer radius is equal to the sum of the inner radius and the side length of the sub-aperture, ensuring that the ring width of adjacent regions matches the sub-aperture size. In addition, the sum of the inner radius and the first width of each subsequent region is equal to the outer radius of the previous region. This ensures that all adjacent regions across the entire aperture meet the overlap requirements, forming a continuous radial coverage network.

[0046] Furthermore, based on the actual aperture of the large-aperture spherical optical element, the total number of required annular scanning areas is calculated to ensure that the outer radius of the outermost annular area covers the edge of the surface to be scanned, and that all annular areas, when combined, cover the entire surface to be scanned without omission or redundancy.

[0047] Furthermore, the specific implementation steps for determining multiple annular scanning regions on the large-aperture spherical optical element based on the central spatial position and scanning sub-aperture size parameters include:

[0048] (1) Using the central spatial position as the common centroid, determine the amplification width according to the scanning sub-aperture size parameters;

[0049] Specifically, taking the central spatial location as a common centroid, and combining the size parameters of the scanning sub-aperture (which may include the side length of the scanning sub-aperture), the amplification width between adjacent annular scanning regions is calculated. It should be noted that if the scanning sub-aperture is square, its diameter is the sum of the distances from the centroid to the two opposite sides; if the scanning sub-aperture is circular, its diameter is the sum of the distances from the circle to the two opposite points.

[0050] Furthermore, the size of the scanning sub-aperture can be equal to, smaller than, or larger than the width of the annular scanning area; in this embodiment, it is not limited. The scanning sub-aperture size parameter is determined jointly based on the object-side field of view and imaging resolution requirements of the detection system, directly affecting the ring width of the annular area and the sub-aperture distribution density. For example, if the maximum object-side field of view of the system is 15mm × 12mm, the sub-aperture side length can be set to 8mm~12mm.

[0051] (2) The surface to be scanned of the large-aperture spherical optical element is divided into multiple continuous annular scanning areas from the inside to the outside until the combination of multiple annular scanning areas covers the surface to be scanned.

[0052] Specifically, if the size of the scanning sub-aperture is equal to the width of the annular scanning area, starting from the central region of the surface to be scanned of the large-aperture spherical optical element, the annular scanning area is divided layer by layer from the inside out, with the central spatial position as the center and the amplification width as the outer boundary. The inner boundary of the first annular scanning area is the center position, and the outer boundary is the amplification width. The inner boundary of the second annular area coincides with the outer boundary of the first area, and the outer boundary is the inner boundary plus the amplification width. This process continues until the outer boundary of the outermost annular area covers the edge of the surface to be scanned. All annular areas are continuously connected and cover the entire surface to be scanned without omission.

[0053] The inside-out division sequence and continuous expansion logic ensure that the annular scanning area is symmetrically distributed with the center as the reference, perfectly adapting to the annular symmetry characteristics of the sphere; continuous coverage is achieved by overlapping area boundaries, avoiding edge omissions or repeated scanning problems that are easy to occur in traditional grid division, laying the foundation for the integrity of full-aperture scanning.

[0054] Furthermore, the method provided in this embodiment also includes:

[0055] (1) When the size of the scanning sub-aperture is greater than the width of the annular scanning area, the standard reference width of the first annular scanning area is calculated with the center spatial position as the origin, based on the imaging resolution requirements, the actual size of the sub-aperture and the preset minimum scanning overlap rate.

[0056] (2) For the first annular region that has been defined, collect the portion of each sub-aperture that exceeds the first annular scanning region and calculate the defect probability of the portion;

[0057] (3) Calculate the width scaling factor based on the defect probability, and use the product of the standard reference width and the defect probability as the width of the next annular scanning area.

[0058] Furthermore, if the size of the scanning sub-aperture is larger than the width of the annular scanning area, taking the center spatial position of the large-aperture spherical optical element as the origin, and combining the imaging resolution requirements of the detection system, the actual size of the sub-aperture, and the preset minimum scanning overlap rate, the standard reference width of the first annular scanning area is calculated. For the defined first annular area, starting from a point on the inner edge of the first area, the three-dimensional displacement stage is controlled to move the sub-aperture clockwise. Each time it moves to a preset sub-aperture position, the focusing scan of that sub-aperture is completed, and imaging data of the part of each sub-aperture that exceeds the first annular scanning area is collected simultaneously. That is, the area where the outer edge of the sub-aperture exceeds the outer boundary of the first area can be captured. The imaging data can include surface gray value distribution, local curvature deviation, that is, the difference with the preset spherical model, and suspected defects (protrusions / The pixel ratio of the recessed area is used; the imaging data of the first annular scan region is identified using a defect recognition algorithm and quantitatively analyzed to calculate the defect probability; a width scaling factor is calculated based on the defect probability; the product of the standard reference width and the defect probability of the current annular scan region is used as the width of the next annular scan region, and the defect probability calculation is performed on the next annular scan region, and so on, until the sum of the widths of all annular scan regions is greater than the surface of the optical element. It should be noted that when calculating the width scaling factor based on the defect probability, a high defect probability indicates a higher probability of defects in the undefined areas outside the current region. Therefore, the width of the next annular region needs to be reduced to decrease the area of ​​the sub-aperture exceeding the limit in the next region. Thus, the higher the defect probability, the smaller the corresponding width scaling factor.

[0059] Furthermore, if the size of the scanning sub-aperture is smaller than the width of the annular scanning area, based on the central spatial position, and according to the radial coverage requirements of the annular scanning area, it is necessary to cover the complete radial range from the inner edge to the outer edge. Combining the sub-aperture size with the preset radial overlap rate (which is set according to actual needs), the number of sub-aperture arrays required for the current annular area is calculated. The width of the current annular area is divided radially into layered intervals matching the number of sub-apertures. Each layered interval corresponds to the coverage range of one sub-aperture, and adjacent layered intervals must meet the radial overlap rate. Within each layered interval, the circumferential scanning path of the sub-aperture is planned in a clockwise direction. Based on the perimeter of the annular area and the circumferential size of the sub-aperture, the circumferential spacing between adjacent sub-apertures is calculated to ensure that the circumferential overlap rate is not lower than the preset value. After completing the scanning of all sub-apertures in the current annular region, the imaging data of all sub-apertures are stitched together into a complete three-dimensional topographic image of the annular region using an image stitching algorithm. This verifies whether the radial range after stitching completely matches the width of the initially defined region. If there is a radial gap after stitching, the width of the next annular region is increased based on the original calculation. If there is excessive overlap, the width of the next region is reduced to ensure that the width of each annular region can both adapt to the sub-aperture size and achieve efficient and non-redundant coverage of the entire aperture.

[0060] S103. Traverse each of the annular scanning regions to complete the three-dimensional scanning of the large-aperture spherical optical element; wherein, for each of the annular scanning regions, scanning is performed through multiple sub-apertures, and when scanning the current annular scanning region, the spatial coordinates of the current sub-aperture are calculated based on the position information of the current annular scanning region, and the current sub-aperture is scanned based on the spatial coordinates.

[0061] Specifically, each annular scanning area is traversed in an order from the inside out. That is, starting from the first annular scanning area closest to the center spatial position, after scanning the first annular scanning area, the second annular scanning area adjacent to the first annular scanning area is scanned, and so on, until all annular scanning areas are scanned.

[0062] Furthermore, the specific implementation steps for traversing each of the aforementioned annular scanning regions include:

[0063] (1) For the current annular scanning area, based on the ring width between the inner and outer edges of the annular scanning area, and combined with the scanning sub-aperture size parameters, determine the number of scanning sub-apertures within the annular scanning area;

[0064] Specifically, based on the ring width between the inner and outer edges of the current annular scanning area, and combined with the size parameters of the scanning sub-apertures, the required number of sub-apertures for the current annular scanning area is calculated. Specifically, the ring width needs to match the radial coverage width of the sub-apertures, while ensuring that adjacent sub-apertures have a preset radial overlap (e.g., 10%~20% of the sub-aperture side length) to avoid scanning gaps caused by mismatch between the ring width and sub-aperture dimensions. For example, if the ring width is 10mm and the radial side length of the sub-aperture is 8mm, at least two sub-apertures are needed to cover this ring width (with an overlap of 6mm). This quantity matching ensures full radial coverage of the annular area. By calculating the correlation between the ring width and the sub-aperture dimensions, the number of sub-apertures is accurately determined, avoiding missed scans due to insufficient quantity and reducing redundant scans due to excessive quantity.

[0065] Furthermore, the radial overlap ratio of the sub-apertures is dynamically adjusted based on the real-time scanning results of the current annular scanning area. During the sub-aperture scanning of the current annular area, the surface feature data of the scanned sub-aperture coverage area is extracted by the data acquisition unit. This data may include grayscale fluctuations, local curvature deviations, and the proportion of suspected defective pixels. The probability of defects appearing in the area is predicted based on the defect identification algorithm. The radial overlap ratio is adjusted according to the probability of defects appearing. The higher the probability of defects appearing, the larger the corresponding radial overlap ratio.

[0066] For example, if the predicted defect probability is greater than a first threshold, indicating a high defect risk, the radial overlap ratio of adjacent sub-apertures is increased. This increases the overlap area, enhancing repeated scanning of high-risk areas and reducing the probability of missed defects. If the predicted defect probability is less than a second threshold, indicating a low defect risk, the overlap ratio can be maintained, ensuring detection integrity while reducing redundant scanning and balancing detection accuracy and efficiency. Overlap parameters are optimized through scan feedback to improve the targeting of defect detection. It should be noted that the comparison thresholds used to determine the risk level based on defect probability—namely, the first and second thresholds—are set according to actual needs and are not limited in this embodiment.

[0067] Furthermore, the distribution spacing of sub-apertures within the annular scanning area needs to be customized based on the geometric characteristics of the area. If the radial cross-section of the annular scanning area is circular, such as a standard arc cross-section of a circle or ring, due to its uniform circumferential curvature and lack of significant abrupt corner changes, the sub-apertures are distributed at equal intervals. The average radius of the annular area is used as a reference, where the average radius refers to the average of the inner and outer edge radii. The circumferential length of the annular area is evenly divided according to the number of sub-apertures, and the center-to-center spacing between adjacent sub-apertures remains consistent, ensuring seamless circumferential coverage and uniform distribution. This adapts to the symmetrical characteristics of the circular shape area and simplifies path planning and displacement stage control logic. If the radial cross-section of the annular scanning area is circular, such as a standard arc cross-section of a circle or ring, the sub-apertures are distributed at equal intervals. This adapts to the symmetrical characteristics of the circular shape area and simplifies path planning and displacement stage control logic. For non-standard cross-sections with square or obtuse corners at the edges of annular regions, the curvature of the spherical surface at the corners is prone to abrupt changes. For example, the radius of curvature at a square corner may decrease sharply. Therefore, a distribution strategy is required where the spacing between sub-apertures at the corners is smaller than the spacing at the sides. In the straight-edge sections of the square region, the spacing between adjacent sub-apertures is set according to the equal spacing standard of the central region. In the corner sections, the spacing between adjacent sub-apertures is reduced to a fixed proportion of the spacing in the straight-edge sections. By densifying the sub-aperture distribution, the scanning coverage of the curvature-abrupt areas at the corners is enhanced, avoiding the missed detection of defects due to excessive spacing at the corners. At the same time, the geometric characteristics of the square region are adapted to ensure that the sub-aperture imaging data can be completely stitched together to form the three-dimensional topography at the corners.

[0068] (2) Starting from any point on the side of the annular scanning area closest to the center spatial position, determine the spatial coordinates of each scanning sub-aperture in a clockwise direction, scan the annular scanning area, and after the scan is completed, traverse the next annular scanning area.

[0069] Specifically, the inner edge of the current annular scanning area is defined as the side closest to the center. Any point on this inner edge serves as the starting point, representing the initial coordinates of the first sub-aperture. Starting from this point, the scan proceeds clockwise along the circumference of the annular scanning area. The angle of each offset is calculated based on the number of sub-apertures and the circumference of the annular area, while ensuring a pre-defined overlap between adjacent sub-apertures in the circumference. This determines the spatial coordinates of each sub-aperture. After scanning all sub-apertures in the current annular scanning area, the process switches to the next annular scanning area, repeating the process until all areas are scanned. This ensures a regular distribution of sub-apertures within the annular area, facilitating path planning and mechanical control. Starting from the side closest to the center ensures an orderly expansion of the sub-aperture distribution from the inside out, adapting to the radial characteristics of the annular area and further reducing unnecessary movement of the stage, thus improving traversal efficiency. The sequential switching between areas guarantees the continuity of the full-aperture scan, ultimately achieving coverage without blind spots.

[0070] Preferably, when the annular scanning area is circular, the starting position is the intersection of the edge of the annular area, the center spatial position, and a preset reference direction. The preset reference direction needs to be compatible with the spatial coordinate system of the detection system. It can be a direction horizontally to the right along the optical axis or perpendicular to the optical axis upwards. Taking the center spatial position as the origin, a ray is drawn along the reference direction. The intersection of the ray with the edge of the current annular area is the starting point of the first sub-aperture. For example, if the optical axis is horizontally to the right as the reference direction, the center spatial position is point O, and a ray is drawn horizontally to the right, intersecting the edge of the current annular area at point A, then point A is the starting point of the sub-aperture. This starting point ensures that the initial position of the sub-aperture is consistent with the system coordinate system reference, simplifying subsequent coordinate calculations. The ending point needs to form a circumferential closed loop coverage with the starting point, and ensure that the last sub-aperture has a preset circumferential overlap with the starting sub-aperture. Specifically, after scanning all sub-apertures clockwise from the starting point, the ending position of the last sub-aperture must cover a portion of the starting sub-aperture's area. If the number of sub-apertures is N, and the coverage angle of a single circumferential sub-aperture is α, then the corresponding angle of the ending point is the starting angle + N × α, and it must satisfy the condition that the ending angle - 360° ≤ starting angle + α × 15%, meaning the overlap angle between the last sub-aperture and the starting sub-aperture is not less than α × 15%, ensuring no scanning gap in the circumferential direction. For example, if the starting angle is 0°, α = 40°, and N = 9, then the ending angle is 0° + 9 × 40° = 360°, and the coverage angle of the last sub-aperture is 320° - 360°, overlapping the starting sub-aperture (0° - 40°) by 20° (accounting for 50% of α), satisfying the closed-loop coverage requirement; furthermore, the starting points of all annular regions are collinear with the central spatial position, meaning the starting points of different annular regions are all on the same ray from the central spatial position to the preset reference direction. For example, if the starting point of the inner annular region is A, and the starting point of the outer annular region is A', and the intersection of the inner edge of the inner region with the reference ray is the point where points O, A, and A' are collinear, then the displacement stage only needs to move radially when switching between adjacent annular regions, significantly reducing the displacement stage's travel distance and positioning time.

[0071] Furthermore, when the annular scanning area is square, the inner vertex of the corner at the edge of the annular area is used as the starting position. Corners in a square area are prone to defects due to abrupt changes in curvature. Setting the starting point as the inner vertex of the corner allows for priority scanning of the corner area, reducing repeated adjustments of the displacement stage at the corners during subsequent scans. For example, if the inner edge of a square-section annular area contains four right-angled corners (vertices 1, 2, 3, and 4), vertex 1 can be selected as the starting point. The starting point sub-aperture must completely cover vertex 1 and a portion of the adjacent straight edges on both sides to ensure no corner is missed in the initial scan. The ending point is set as the inner vertex of the next corner adjacent to the starting point, ensuring that the last sub-aperture completely covers the ending corner and the adjacent straight edges, while also partially overlapping with the starting point sub-aperture. Specifically, the scanning proceeds clockwise from the starting corner, covering the straight edges and the next corner in sequence. After completing the scanning of all sub-apertures, the endpoint must fall on the inner vertex of the next corner. If the edge of the square area contains M corners, the scanning path must cover M straight edges and M corners. In this case, the corner corresponding to the endpoint must be M corners away from the starting corner, i.e., return to the corner adjacent to the starting point. Furthermore, the last sub-aperture must cover part of the area of ​​the endpoint corner and the starting corner. For example, if the starting point is corner 1 and M=4, the scanning path is corner 1 → straight edge 1 → corner 2 → straight edge 2 → corner 3 → straight edge 3 → corner 4 → straight edge 4, and the ending point is set to the adjacent corner of corner 1, such as corner 4. The last sub-aperture covers part of straight edge 4, corner 4, and corner 1 to ensure that there are no scanning gaps between the corner and the straight edge. If the corner of the square area is an obtuse angle, the starting sub-aperture needs to be appropriately increased to cover the corner area to avoid missed scans due to the large area of ​​the obtuse angle. The overlap between the ending sub-aperture and the starting sub-aperture also needs to be increased to ensure that the scanning data on both sides of the obtuse angle corner are completely stitched together.

[0072] Furthermore, the specific steps for traversing each of the aforementioned annular scanning regions to complete the three-dimensional scanning of the large-aperture spherical optical element include:

[0073] (1) Based on the central spatial position, determine the starting position of the scanning sub-aperture within the current annular scanning area, and scan the current annular scanning area in a clockwise direction;

[0074] Specifically, using the central spatial location as a reference, a point is selected on the inner edge of the current annular scanning area as the starting position of the first sub-aperture. Starting from the starting position, the annular area is evenly divided circumferentially according to the number of sub-apertures. Each subsequent sub-aperture is offset by the same angle clockwise relative to the previous one, and the edges of adjacent sub-apertures maintain a preset overlap width. This process is repeated to complete the scanning of all sub-apertures in the current area, ensuring circumferential coverage without any blind spots.

[0075] Furthermore, for each sub-aperture, its coordinates on the horizontal plane are determined first by the average radius of the current annular scanning area and the corresponding circumferential offset angle. The average radius is the average of the inner and outer radii. The scanning operation of all sub-apertures in the current area is completed in a clockwise order to ensure that the circumferential range of the entire annular area is covered.

[0076] (2) After completing the scanning of the current annular scanning area, calculate the first distance from the outer edge of the current annular scanning area to the central spatial position;

[0077] Specifically, after all sub-apertures in the current annular scanning area have been scanned, the radius data of the outer edge of the annular scanning area is extracted according to the preset area parameters in the system. That is, the radial distance from any point on the outer edge to the center spatial position. It should be noted that the radial distance is calculated only on the horizontal plane and does not include the vertical direction.

[0078] Furthermore, multiple symmetrically distributed points on the outer edge are selected, and the radial distance from each point to the central spatial location is calculated. The average of these radial distances is then taken as the first distance. Through multi-point calculation and averaging, the inaccuracy of distance data caused by regional division errors or measurement deviations can be effectively reduced, ensuring that the accuracy of the first distance is controlled at the micrometer level, providing reliable basic parameters for subsequent calculations connecting adjacent regions.

[0079] (3) Based on the first distance and the second distance from the inner edge of the next annular scanning area to the center spatial position, determine the radial movement value between the current annular scanning area and the next annular scanning area;

[0080] Specifically, the second distance between the inner edge of the next annular scanning area and the center spatial position is obtained, and the radial movement value is calculated based on the difference between the first and second distances. It should be noted that the calculation method for the second distance is the same as that for the first distance, and will not be repeated here.

[0081] (4) Move the scanning sub-aperture to the starting position of the next annular scanning area according to the radial movement value, take the next annular scanning area as the current annular scanning area, return to the step of determining the starting position of the scanning sub-aperture in the current annular scanning area, until the scanning of the last annular scanning area is completed.

[0082] Specifically, the radial movement of the displacement stage is controlled to move the sub-aperture from the last sub-aperture position in the current annular scanning area to the starting position of the next annular scanning area. The starting position needs to maintain the same circumferential direction as the starting position of the current area, for example, corresponding to the same horizontal reference direction, and located on the inner edge of the next area, with the distance from the center spatial position exactly equal to the second distance. After the movement operation is completed, the actual coordinates of the starting position of the next area are collected by the spectral confocal sensor and compared with the theoretically calculated coordinates. If the deviation between the actual coordinates and the theoretical coordinates is within the allowable range, the positioning is confirmed to be effective, the next annular scanning area is set as the new current annular scanning area, and the operation of step (1) is returned. If the deviation exceeds the allowable range, the displacement stage is driven to make minor adjustments until the positioning accuracy of the starting position meets the requirements. The operation is repeated until all annular scanning areas are scanned.

[0083] The starting position of the sub-aperture is determined based on the central spatial position, and scanning is performed in a clockwise direction. This ensures that the sub-apertures are symmetrically distributed within each annular region, conforming to the spherical annular symmetry characteristics. This avoids missed scans or duplications caused by chaotic paths and facilitates precise and repeated positioning by the mechanical system. After the current region is scanned, the radial movement value is accurately calculated by quantifying the distance from the outer edge to the center and the distance from the inner edge to the center of the next region. This ensures seamless radial connection between adjacent regions, with no scanning gaps or redundant scans. Combining clockwise circumferential scanning with orderly radial movement significantly reduces the ineffective travel of the displacement stage. With the help of loop logic, the entire process is automated, significantly improving scanning efficiency.

[0084] Furthermore, the specific steps for calculating the spatial coordinates of the current sub-aperture based on the position information of the current annular scanning area include:

[0085] (1) Determine the radius of the current annular scanning area based on the location information of the current annular scanning area;

[0086] Specifically, based on the location information of the current annular scanning area, namely the distance from the inner edge and outer edge to the center spatial position, the area radius of the current annular scanning area is determined. The area radius is usually the average of the inner edge radius and the outer edge radius, which can represent the radial center position of the annular area and adapt to the radial coverage range of the sub-aperture, ensuring that the center of the sub-aperture falls in the middle layer of the annular area and avoiding the sub-aperture from exceeding the area range due to radius deviation.

[0087] (2) Taking the central spatial position as the origin of the XY plane, and combining it with the region radius, determine the circumferential range of the current annular scanning region in the XY plane;

[0088] Specifically, taking the central spatial position as the origin of the XY plane coordinates, and combining the region radius, the circumferential range of the current annular scanning area in the XY plane is defined. The circumferential range is an annular area with the origin as the center and the inner and outer edge radii as the boundaries, covering all radial positions from the inner edge to the outer edge, and completely encompassing 360 degrees in the circumferential direction, ensuring that the geometric boundary of the annular area is clearly distinguishable.

[0089] (3) Based on the number of scanning sub-apertures distributed in the current annular scanning area, the circumferential range is divided in a clockwise direction to obtain the circumferential position interval of each scanning sub-aperture in the XY plane;

[0090] Specifically, based on the preset number of scanning sub-apertures within the current annular scanning area, the circumferential range is evenly divided clockwise to obtain annular position intervals equal to the number of sub-apertures. Each circumferential position interval has the same angular range, and the edges of adjacent intervals overlap to ensure that the sub-apertures cover the annular area without gaps in the circumferential direction. For example, if there are eight sub-apertures, each interval corresponds to a 45-degree range, and the overlapping portion of adjacent intervals meets the coverage requirements of the sub-aperture edges.

[0091] (4) For the current scanning sub-aperture, based on the origin of the coordinate system and in combination with the circumferential position interval and the radius of the region, determine the coordinates of the current scanning sub-aperture in the X-axis direction and the Y-axis direction;

[0092] (5) Determine the spatial coordinates of the current scanning sub-aperture based on the coordinates in the X-axis direction and the Y-axis direction.

[0093] Specifically, for the sub-aperture that needs to be scanned, the coordinates in the X-axis and Y-axis directions are calculated based on the origin of the XY plane coordinates and the circumferential position range to which the sub-aperture belongs, i.e., the corresponding angle range and area radius.

[0094] Furthermore, based on the midpoint angle of the circumferential position interval and the region radius, the X-axis and Y-axis coordinates are calculated using trigonometric functions. This ensures that the center of the sub-aperture falls precisely within its corresponding circumferential interval and maintains a preset overlap width with adjacent sub-apertures. Transforming the geometric characteristics of the annular scanning area into precise spatial coordinates for the sub-apertures not only adapts to the annular symmetry of the sphere but also ensures accurate sub-aperture positioning through uniform distribution and geometric calculations, providing a solid coordinate foundation for subsequent efficient and high-precision scanning operations.

[0095] Furthermore, the steps for calculating the spatial coordinates of the current sub-aperture include:

[0096] (1) Divide the current annular scanning area into four quadrants with the central spatial position as the origin;

[0097] (2) Determine the X and Y offsets of each quadrant based on the central spatial position, wherein the X and Y offsets of the first quadrant are the same as those of the third quadrant, and the X and Y offsets of the second quadrant are the same as those of the fourth quadrant.

[0098] (3) Determine the sign of the X and Y offsets for each quadrant based on the characteristics of each quadrant;

[0099] (4) Calculate the spatial coordinates of the current sub-aperture in each quadrant based on the central spatial position and the X and Y offsets of each quadrant.

[0100] Specifically, the spatial coordinates of the current sub-aperture can be represented as:

[0101] First Quadrant: ;

[0102] Second Quadrant: ;

[0103] Third Quadrant: ;

[0104] Fourth Quadrant: ;

[0105] This is the sequence number of the current circular scan region;

[0106] This indicates the number of sub-apertures in each group after the current annular scanning area is divided. ;

[0107] The spatial coordinates of the j-th sub-aperture in the current annular scanning region;

[0108] The X offset is between the first and third quadrants;

[0109] This represents the Y offset between the first and third quadrants;

[0110] The X offset is for the second and fourth quadrants;

[0111] This represents the Y offset in the second and fourth quadrants;

[0112] k is in the kth quadrant;

[0113] d is the side length of a single sub-aperture.

[0114] The four sets of formulas correspond to the four quadrants of the annular region. For example, the first quadrant expands along the positive Y-axis, and the second quadrant expands along the negative X-axis. Based on the X and Y coordinates in the central spatial position, the annular region number and radial distance are associated through the X offset to ensure that the sub-apertures are distributed in a stepped manner from the inside to the outside. At the same time, the Y offset controls the circumferential offset of the sub-apertures within the group, so that the sub-apertures are evenly arranged in the 360° circumferential direction, perfectly conforming to the annular symmetrical geometric characteristics of the sphere and avoiding local scanning blind spots.

[0115] Furthermore, after setting the scanning path of the scanning sub-aperture, the depth of field corresponding to each scanning sub-aperture is calculated, and the depth of field is used as the Z-axis coordinate corresponding to each sub-aperture, thereby controlling each sub-aperture to perform three-dimensional scanning of the optical element.

[0116] The three-dimensional scanning method for large-aperture spherical optical elements provided in this embodiment divides the surface to be scanned into multiple concentric annular scanning regions based on the spatial position of the optical element's center. This ensures that all regions, when combined, cover the element's surface without gaps. By adapting the annular region division to the spherical annular symmetry, compared to traditional rectangular grid division, it effectively avoids the problem of missed or redundant scanning of edge regions. At the same time, the overlap width reserved between adjacent regions further ensures that there are no blind spots in the full-aperture scanning, ensuring that no defects on the element's surface are missed. Furthermore, a multispectral confocal sensor sampling and centering algorithm are used to fit and calculate the center spatial position, accurately locating the element's center. The calculation of sub-aperture spatial coordinates, combined with the annular region radius and the logic of uniform circumferential division, ensures accurate sub-aperture distribution. Within the same annular scanning region, sub-apertures are continuously scanned in a clockwise direction, and precise switching between regions is achieved by calculating radial movement values, significantly reducing the ineffective travel of the displacement stage. The entire process adopts automated cyclic scanning, eliminating the need for manual intervention in region switching and effectively shortening the overall scanning time.

[0117] Corresponding to the aforementioned embodiment of a three-dimensional scanning method for a ring-shaped large-aperture spherical optical element, this application also provides an embodiment of a three-dimensional scanning device for a ring-shaped large-aperture spherical optical element.

[0118] Figure 3 This is a schematic diagram of the structure of Embodiment 2 of the three-dimensional scanning device for a ring-shaped large-aperture spherical optical element provided in this application. Please refer to... Figure 3 The device provided in this embodiment includes an installation module 310, a calculation module 320, and a scanning module 330; wherein,

[0119] The mounting module 310 is used to mount the large-aperture spherical optical element;

[0120] The calculation module 320 is used to determine multiple annular scanning regions on the large-aperture spherical optical element based on the central spatial position and scanning sub-aperture size parameters of the large-aperture spherical optical element; wherein, all annular scanning regions are ring-shaped regions with the central spatial position as the center, and the combination of all annular scanning regions covers the surface to be scanned of the large-aperture spherical optical element.

[0121] The scanning module 330 is used to traverse each of the annular scanning areas to complete the three-dimensional scanning of the large-aperture spherical optical element;

[0122] Specifically, for each of the annular scanning regions, scanning is performed using multiple sub-apertures. When scanning the current annular scanning region, the spatial coordinates of the current sub-aperture are calculated based on the position information of the current annular scanning region, and the current sub-aperture is scanned based on the spatial coordinates.

[0123] The apparatus of this embodiment can be used to perform... Figure 1 The steps of the method embodiment shown are similar in principle and process, and will not be repeated here.

[0124] The specific implementation process of the functions and roles of each unit in the above device can be found in the implementation process of the corresponding steps in the above method, and will not be repeated here.

[0125] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and 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 modules can be selected to achieve the purpose of this application according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0126] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A three-dimensional scanning method of a large aperture spheric optical element in the form of a ring, characterized in that, The method comprises: installing the large-aperture spherical optical element; determining a plurality of annular scanning regions on the large-aperture spherical optical element based on the central spatial position of the large-aperture spherical optical element and the scanning sub-aperture size parameter; wherein all annular scanning regions are annular regions with the central spatial position as the center, and all annular scanning regions combine to cover the surface to be scanned of the large-aperture spherical optical element; wherein the determination of the plurality of annular scanning regions on the large-aperture spherical optical element based on the central spatial position of the large-aperture spherical optical element and the scanning sub-aperture size parameter comprises: determining an amplification width according to the scanning sub-aperture size parameter with the central spatial position as the common center; dividing the surface to be scanned of the large-aperture spherical optical element into a plurality of continuous annular scanning regions from inside to outside until the combination of the plurality of annular scanning regions covers the surface to be scanned; traversing each annular scanning region to complete three-dimensional scanning of the large-aperture spherical optical element; wherein for each annular scanning region, scanning is performed through a plurality of sub-apertures, and when scanning the current annular scanning region, the spatial coordinates of the current sub-aperture are calculated based on the position information of the current annular scanning region, and the current sub-aperture is scanned based on the spatial coordinates.

2. The method of claim 1, wherein, The width of the overlapping region between adjacent annular scanning regions is a first width, the first width is in a positive proportional relationship with the diameter of the scanning sub-aperture, and is in a positive proportional relationship with the distance between the centers of adjacent scanning sub-apertures in the same annular scanning region, and the traversing of each annular scanning region to complete three-dimensional scanning of the large-aperture spherical optical element comprises: determining the scanning start point and the scanning end point of the current annular scanning region; starting from the scanning start point, scanning the current annular scanning region based on the sub-apertures until the scanning end point is reached, the distance between the centers of adjacent sub-apertures in the same annular scanning region is less than the diameter of the sub-aperture, and the distance between the two closest sub-apertures in adjacent annular scanning regions is less than the diameter of the sub-aperture; determining the next annular scanning region adjacent to the current annular scanning region and not scanned, determining the target sub-aperture closest to the scanning end point in the next annular scanning region, and taking the target sub-aperture as the start sub-aperture of the next annular scanning region.

3. The method of claim 1, wherein, The traversing of each annular scanning region to complete three-dimensional scanning of the large-aperture spherical optical element comprises: determining the starting position of the scanning sub-aperture in the current annular scanning region with the central spatial position as the reference, and scanning the current annular scanning region in the clockwise direction; after completing the scanning of the current annular scanning region, calculating the first distance from the outer edge of the current annular scanning region to the central spatial position; based on the first distance and the second distance from the inner edge of the next annular scanning region to the central spatial position, determining the radial movement value between the current annular scanning region and the next annular scanning region; moving the scanning sub-aperture to a starting position of a next annular scanning region according to the radial movement value, taking the next annular scanning region as a current annular scanning region, returning to the step of determining the starting position of the scanning sub-aperture in the current annular scanning region until scanning of a last annular scanning region is completed.

4. The method of claim 1, wherein, The step of traversing each of the annular scanning regions comprises: For a current annular scanning region, a number of scanning sub-apertures in the annular scanning region is determined according to a ring width between an inner edge and an outer edge of the annular scanning region and a scanning sub-aperture size parameter; A space coordinate of each scanning sub-aperture is determined in a clockwise direction from a starting position of any point on a side of the annular scanning region close to the central space position, and the annular scanning region is scanned, and after the scanning is completed, a next annular scanning region is traversed.

5. The method of claim 1, wherein, The step of calculating the space coordinate of the current sub-aperture based on the position information of the current annular scanning region comprises: The area radius of the current annular scanning region is determined according to the position information of the current annular scanning region; The annular scanning region is divided into four quadrants with the central space position as a coordinate origin. The annular scanning region is divided along the clockwise direction according to the number of scanning sub-apertures in the current annular scanning region, to obtain an annular position interval of each scanning sub-aperture in the XY plane. For a current scanning sub-aperture, the coordinate of the current scanning sub-aperture in the X-axis direction and the coordinate of the current scanning sub-aperture in the Y-axis direction are determined based on the coordinate origin, the annular position interval and the area radius. The space coordinate of the current scanning sub-aperture is determined according to the coordinate in the X-axis direction and the coordinate in the Y-axis direction.

6. The method of claim 1, wherein, The step of determining the plurality of annular scanning regions on the large-aperture spherical optical element based on the central space position and the scanning sub-aperture size parameter further comprises: When the scanning sub-aperture size is greater than the width of the annular scanning region, a standard reference width of a first annular scanning region is calculated based on an imaging resolution requirement, an actual size of a sub-aperture and a preset minimum scanning overlap rate, with the central space position as the origin. For the first annular region, a part of each sub-aperture exceeding the first annular scanning region is collected, and a defect probability of the part is calculated. A width scaling coefficient is calculated according to the defect probability, and a product of the standard reference width and the defect probability is taken as a width of a next annular scanning region.

7. The method of claim 1, wherein, The large-aperture spherical optical element is vertically installed on a sample table, the sample table is installed on a three-dimensional displacement table, an optical axis of the large-aperture spherical optical element is parallel to a horizontal plane, a plurality of spectral confocal sensors and an illumination light source are fixed on the same side, a range of the plurality of spectral confocal sensors is determined according to a working distance of a detection element of the plurality of spectral confocal sensors, and a surface to be scanned of the large-aperture spherical optical element faces an imaging direction of a detection system.

8. The method of claim 1, wherein, The step of calculating the space coordinate of the current sub-aperture comprises: The current annular scanning region is divided into four quadrants with the central space position as the origin. According to the center space position, X offset and Y offset of each quadrant are determined, wherein the X offset and Y offset of the first quadrant are the same in value as the X offset and Y offset of the third quadrant, and the X offset and Y offset of the second quadrant are the same in value as the X offset and Y offset of the fourth quadrant; According to the characteristics of each quadrant, the signs of the X offset and Y offset of each quadrant are determined; According to the center space position and the X offset and Y offset of each quadrant, the spatial coordinates of the current sub-aperture in each quadrant are calculated.

9. A three-dimensional scanning apparatus of a large aperture spherical optical element in a ring form, characterized by, The device comprises a mounting module, a calculation module and a scanning module; wherein, The mounting module is configured to mount the large-aperture spherical optical element; The calculation module is configured to determine a plurality of annular scanning regions on the large-aperture spherical optical element based on the center space position and scanning sub-aperture size parameters of the large-aperture spherical optical element; wherein all annular scanning regions are annular regions with the center space position as the center, and all annular scanning regions combined cover the surface to be scanned of the large-aperture spherical optical element; wherein the determination of the plurality of annular scanning regions on the large-aperture spherical optical element based on the center space position and scanning sub-aperture size parameters comprises: Determining an expansion width according to the scanning sub-aperture size parameters with the center space position as the common center; Dividing the surface to be scanned of the large-aperture spherical optical element into a plurality of continuous annular scanning regions from inside to outside until the combination of the plurality of annular scanning regions covers the surface to be scanned; The scanning module is configured to traverse each annular scanning region to complete the three-dimensional scanning of the large-aperture spherical optical element; For each annular scanning region, scanning is performed through a plurality of sub-apertures, and when scanning the current annular scanning region, the spatial coordinates of the current sub-aperture are calculated based on the position information of the current annular scanning region, and the current sub-aperture is scanned based on the spatial coordinates.

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