Method, device and equipment for measuring curvature radius of vertex of aspheric surface and storage medium

Abstract

The invention belongs to the technical field of optical manufacturing, and discloses an aspheric surface vertex curvature radius measurement method, device and equipment and a storage medium, and the method comprises the steps: obtaining the size data of an aspheric reflector, and according to the size data, combining a preset aspheric surface local sampling density calculation formula and a preset edge region encryption criterion, obtaining an aspheric surface vertex curvature radius; generating a measurement dot matrix, measuring the position coordinates of the measurement dot matrix to obtain measurement data corresponding to the measurement dot matrix, and calculating the actual aspheric vertex curvature radius of the aspheric reflector based on the measurement data by using a local search algorithm; through the local search algorithm, the actual aspheric vertex curvature radius of the aspheric reflector is calculated based on the measurement data corresponding to the measurement dot matrix generated by the preset aspheric local sampling density calculation formula and the preset edge region encryption criterion, and the measurement efficiency of the aspheric vertex curvature radius is improved.

Description

Technical Field

[0001] The present application relates to the technical field of optical manufacturing. Specifically, it relates to a method, device, equipment, and storage medium for measuring the vertex curvature radius of an aspherical surface. Background Technique

[0002] Using aspherical optical elements in an optical system can not only increase the degree of freedom of optical design, facilitate aberration correction, and improve the imaging quality of the optical system, but also reduce the number of optical elements in the optical system, thereby simplifying the mechanical structure design and greatly reducing the size and weight of the system. As one of the most important shape parameters of an aspherical optical element, the accuracy of the vertex curvature radius will largely affect the final performance of a precision optical system. Therefore, the measurement of the vertex curvature radius becomes crucial.

[0003] Traditional methods for measuring the vertex curvature radius of an aspherical surface need to rely on a laser tracker or a profile measuring instrument. However, the prices of both of these devices are relatively expensive, and the accuracy of the laser tracker is poor. Usually, its measurement accuracy can only be controlled at about ±0.05 mm, while the measurement aperture of the profile measuring instrument is usually limited, and its detection is limited by the roughness of the aspherical surface to be inspected, so it is not suitable for most detection scenarios.

[0004] Therefore, in order to solve the technical problems that the existing methods for measuring the vertex curvature radius of an aspherical surface have disadvantages such as expensive measurement equipment, low measurement accuracy, or limited applicable scenarios, there is an urgent need for a method, device, equipment, and storage medium for measuring the vertex curvature radius of an aspherical surface. Summary of the Invention

[0005] The purpose of the present application is to provide a method, device, equipment, and storage medium for measuring the vertex curvature radius of an aspherical surface. Through a local search algorithm, based on the measurement data corresponding to the measurement lattice generated by a preset aspherical local sampling density calculation formula and a preset edge region encryption criterion, the actual vertex curvature radius of the aspherical mirror is calculated, solving the problems that the existing methods for measuring the vertex curvature radius of an aspherical surface have disadvantages such as expensive measurement equipment, low measurement accuracy, or limited applicable scenarios. By quantitatively evaluating the sampling density and sampling position of the aspherical mirror, the vertex curvature radius of the aspherical surface is measured, improving the measurement efficiency of the vertex curvature radius of the aspherical surface.

[0006] In a first aspect, the present application provides a method for measuring the vertex curvature radius of an aspherical surface, including: Obtain the size data of the aspherical mirror; According to the size data, in combination with a preset aspherical local sampling density calculation formula and a preset edge region encryption criterion, generate a measurement lattice; Measure the position coordinates of the measurement lattice to obtain measurement data corresponding to the measurement lattice; Using a local search algorithm, based on the measurement data, the actual aspherical vertex curvature radius of the aspherical mirror is calculated.

[0007] The method for measuring the aspherical vertex curvature radius provided by this application can measure the aspherical vertex curvature radius. Through a local search algorithm, based on the measurement data corresponding to the measurement lattice generated by a preset aspherical local sampling density calculation formula and a preset edge region encryption criterion, the actual aspherical vertex curvature radius of the aspherical mirror is calculated, solving the problems of existing methods for measuring the aspherical vertex curvature radius, such as expensive measurement equipment, low measurement accuracy, or limited applicable scenarios. By quantitatively evaluating the sampling density and sampling position of the aspherical mirror, the aspherical vertex curvature radius is measured, improving the measurement efficiency of the aspherical vertex curvature radius.

[0008] Optionally, the preset aspherical local sampling density calculation formula includes a local sampling density calculation formula based on the curvature radius and a local sampling density calculation formula based on the sagitta.

[0009] Optionally, generating a measurement lattice according to the size data, in combination with a preset aspherical local sampling density calculation formula and a preset edge region encryption criterion, includes: According to the size data, in combination with the local sampling density calculation formula based on the curvature radius and the local sampling density calculation formula based on the sagitta, the sampling density of each position point of the aspherical mirror is calculated; Based on the sampling density and the preset edge region encryption criterion, a measurement lattice is generated.

[0010] The method for measuring the aspherical vertex curvature radius provided by this application can measure the aspherical vertex curvature radius. By using the local sampling density calculation formula based on the curvature radius and the local sampling density calculation formula based on the sagitta, the sampling density of each position point of the aspherical mirror is calculated. Based on the sampling density and a preset edge region encryption criterion, the sampling density of the edge region is adjusted to obtain a measurement lattice. By adjusting the sampling density at different positions according to the surface shape change of the aspherical surface, the accuracy of the measurement data is improved.

[0011] Optionally, generating a measurement lattice based on the sampling density and the preset edge region encryption criterion includes: Generating a sampling lattice corresponding to the sampling density; Determining the region outside the preset percentage of the maximum aperture region in the aspherical mirror as the edge region; Based on the preset edge region encryption criterion, the number of sampling points is increased for the sampling density of the sampling lattice located in the edge region to obtain a measurement lattice.

[0012] Optionally, using a local search algorithm, based on the measurement data, calculate the actual aspherical vertex curvature radius of the aspherical mirror, including: Based on the measurement data, fit the nominal vertex curvature radius of the aspherical mirror at the vertex; Using the damped least squares method with the nominal vertex curvature radius as the initial value, iterate the vertex curvature radius of the aspherical mirror to minimize the surface shape RMS value corresponding to the iterated vertex curvature radius, and obtain the actual aspherical vertex curvature radius of the aspherical mirror.

[0013] The method for measuring the aspherical vertex curvature radius provided by this application can measure the aspherical vertex curvature radius. Using the nominal vertex curvature radius as the initial value for subsequent iterative calculations provides a relatively reasonable starting point for subsequent iterative calculations. Using the damped least squares method with the nominal vertex curvature radius as the initial value, iteratively obtain the vertex curvature radius corresponding to the minimum surface shape RMS as the actual aspherical vertex curvature radius, improving the measurement efficiency of the aspherical vertex curvature radius.

[0014] Optionally, based on the measurement data, fitting the nominal vertex curvature radius of the aspherical mirror at the vertex includes: Perform filtering processing on the measurement data to filter out the noise in the measurement data and obtain the filtered measurement data; Based on the filtered measurement data, fit the nominal vertex curvature radius of the aspherical mirror at the vertex.

[0015] Optionally, after calculating the actual aspherical vertex curvature radius of the aspherical mirror using a local search algorithm based on the measurement data, it further includes: Obtain the theoretical vertex curvature radius of the aspherical mirror, and adjust the processing parameters or processing strategy for processing the aspherical mirror according to the difference between the actual aspherical vertex curvature radius and the theoretical vertex curvature radius.

[0016] In a second aspect, this application provides an apparatus for measuring the aspherical vertex curvature radius, including: An acquisition module for acquiring the size data of the aspherical mirror; A generation module for generating a measurement lattice according to the size data in combination with a preset aspherical local sampling density calculation formula and a preset edge region encryption criterion; A measurement module for measuring the position coordinates of the measurement lattice to obtain measurement data corresponding to the measurement lattice; A calculation module, configured to calculate the actual aspherical vertex curvature radius of the aspherical mirror based on the measurement data by using a local search algorithm.

[0017] The aspherical vertex curvature radius measuring device calculates the actual aspherical vertex curvature radius of the aspherical mirror based on the measurement data corresponding to the measurement lattice generated by a preset aspherical local sampling density calculation formula and a preset edge region encryption criterion through a local search algorithm, solving the problems of existing aspherical vertex curvature radius measurement methods, such as expensive measurement equipment, low measurement accuracy, or limited applicable scenarios. By quantitatively evaluating the sampling density and sampling position of the aspherical mirror, the aspherical vertex curvature radius is measured, improving the measurement efficiency of the aspherical vertex curvature radius.

[0018] In a third aspect, the present application provides an electronic device, including a processor and a memory. The memory stores a computer program executable by the processor. When the processor executes the computer program, it runs the steps in the aspherical vertex curvature radius measurement method described above.

[0019] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it runs the steps in the aspherical vertex curvature radius measurement method described above.

[0020] Beneficial effects: The aspherical vertex curvature radius measurement method, device, equipment, and storage medium provided by the present application calculate the actual aspherical vertex curvature radius of the aspherical mirror based on the measurement data corresponding to the measurement lattice generated by a preset aspherical local sampling density calculation formula and a preset edge region encryption criterion through a local search algorithm, solving the problems of existing aspherical vertex curvature radius measurement methods, such as expensive measurement equipment, low measurement accuracy, or limited applicable scenarios. By quantitatively evaluating the sampling density and sampling position of the aspherical mirror, the aspherical vertex curvature radius is measured, improving the measurement efficiency of the aspherical vertex curvature radius. Description of the Drawings

[0021] Figure 1 It is a flowchart of the aspherical vertex curvature radius measurement method provided by an embodiment of the present application.

[0022] Figure 2 It is a structural schematic diagram of the aspherical vertex curvature radius measurement device provided by an embodiment of the present application.

[0023] Figure 3 It is a structural schematic diagram of the electronic device provided by an embodiment of the present application.

[0024] Label description: 1. Acquisition module; 2. Generation module; 3. Measurement module; 4. Calculation module; 301. Processor; 302. Memory; 303. Communication bus. Detailed implementation manners

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Components of the embodiments of the present application described and illustrated herein generally can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but merely represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0026] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the present application, terms such as "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0027] Please refer to Figure 1 , Figure 1 which is a method for measuring the curvature radius of the aspherical vertex in some embodiments of the present application, used to measure the curvature radius of the aspherical vertex, and includes the steps of: Step S101, obtaining the size data of the aspherical mirror; Step S102, according to the size data, combining the preset aspherical local sampling density calculation formula and the preset edge region encryption criterion, generating a measurement lattice; Step S103, measuring the position coordinates of the measurement lattice to obtain measurement data corresponding to the measurement lattice; Step S104, using a local search algorithm, based on the measurement data, calculating the actual aspherical vertex curvature radius of the aspherical mirror.

[0028] The aspherical vertex curvature radius measurement method calculates the actual aspherical vertex curvature radius of an aspherical mirror by a local search algorithm based on the measurement data corresponding to the measurement lattice generated by a preset aspherical local sampling density calculation formula and a preset edge region encryption criterion, solves the problems of the existing aspherical vertex curvature radius measurement methods, such as expensive measurement equipment, low measurement accuracy, or limited applicable scenarios, measures the aspherical vertex curvature radius by quantitatively evaluating the sampling density and sampling position of the aspherical mirror, and improves the measurement efficiency of the aspherical vertex curvature radius.

[0029] Specifically, in step S101, size data of the aspherical mirror is obtained, where the size data includes data such as the theoretical surface shape, aperture, curvature radius, and sagittal height of the aspherical mirror, and these data can be obtained from design drawings or processing parameters.

[0030] Specifically, the preset aspherical local sampling density calculation formula includes a local sampling density calculation formula based on the curvature radius and a local sampling density calculation formula based on the sagittal height; in step S102, according to the size data, in combination with the preset aspherical local sampling density calculation formula and the preset edge region encryption criterion, a measurement lattice is generated, including: According to the size data, in combination with the local sampling density calculation formula based on the curvature radius and the local sampling density calculation formula based on the sagittal height, the sampling density of each position point of the aspherical mirror is calculated; Based on the sampling density and the preset edge region encryption criterion, a measurement lattice is generated.

[0031] In step S102, by providing these two local sampling density calculation formulas based on the curvature radius and the sagittal height, the measurement method can be adapted to various types of aspherical mirrors. In the actual measurement process, using the local sampling density calculation formula based on the curvature radius and the local sampling density calculation formula based on the sagittal height to generate the sampling density of each position point of the aspherical mirror can ensure that the measurement lattice can fully reflect the surface shape characteristics of the aspherical mirror for different surface shape characteristics of the aspherical mirror, improve the measurement accuracy of the vertex curvature radius and the applicable range of the method.

[0032] Among them, the local sampling density calculation formula based on the curvature radius is specifically: ; Among them, is the sampling density of the position point in the aperture direction; is the curvature radius of the position point ; is the maximum curvature radius of the aspherical surface and the minimum curvature radius of the aspherical surface The median value of, that is ; D is the aperture size of the aspherical mirror (if the shape of the aspherical mirror is rectangular, D represents the aperture size of the circumscribed circle of the rectangle); N is the influence function of the curvature radius sampling density, generally set to 30. Among them, the position point is the surface position point on the aspherical side of the aspherical mirror.

[0033] For the local sampling density calculation formula based on the curvature radius, the sampling density changes with the change of the surface curvature radius of the aspherical mirror. In the area where the curvature radius changes greatly, the sampling density is relatively high, and vice versa. Thus, the measurement points can be more densely distributed in the area where the curvature changes violently, thereby improving the measurement accuracy.

[0034] The specific local sampling density calculation formula based on the sagitta is: ; Among them, is the sampling density of the position point in the sagitta direction; is the sagitta of the position point ; is the maximum sagitta of the aspherical surface and the median value of the minimum sagitta of the aspherical surface that is ; M is the influence function of the sagitta sampling density. The influence function of the sagitta sampling density and the influence function of the curvature radius sampling density can be set to the same value, generally set to 30.

[0035] For the local sampling density calculation formula based on the sagitta, the sampling density changes with the change of the surface sagitta of the aspherical mirror. In the area where the sagitta changes greatly, the sampling density is relatively high, and vice versa. Thus, the measurement points can be more densely distributed in the area where the aspherical surface height changes violently, ensuring the accuracy of the measurement.

[0036] Specifically, in step S102, based on the sampling density and the preset edge region encryption criterion, a measurement dot matrix is generated, including: Generate a sampling dot matrix corresponding to the sampling density; Determine the area outside the preset percentage of the maximum aperture region in the aspherical mirror as the edge region; Based on the preset edge region encryption criterion, increase the number of sampling points for the sampling density of the sampling dot matrix located in the edge region to obtain the measurement dot matrix.

[0037] In step S102, based on the calculated sampling density value, the ratio of the maximum aperture to the sampling density in the aperture direction and the ratio of the maximum sagitta to the sampling density The ratios are used to determine the distances of each sampling point in the aperture direction and the sagittal height direction respectively, generating an initial sampling dot matrix, which can initially ensure the sampling density on the surface of the aspherical mirror. To improve the measurement accuracy in the edge region, starting from the center point of the aperture of the aspherical mirror, a region outside the maximum aperture region at a preset percentage (the preset percentage can be set according to actual needs) (the percentage maximum aperture region is the region within from the center point in the aperture direction, where n is the preset percentage) is defined as the edge region of the aspherical mirror, and the region within the preset percentage maximum aperture region is defined as the central region. For example, if the set percentage is 80%, then starting from the center point of the aperture of the aspherical mirror, the region outside the distance of 40% of the maximum aperture from the center point in the aperture direction is defined as the edge region. Then, according to the preset edge region encryption criterion, the sampling points in the edge region of the initial sampling dot matrix are encrypted (the sampling density is increased) to increase the number of sampling points in the edge region. For example, if the edge region encryption criterion is to increase the sampling point density in the edge region to 1.2 times, then sampling points are added in the edge region so that the sampling point density in the edge region is increased by 20% compared to the density of the initial sampling dot matrix, thereby obtaining the final measurement dot matrix. Measuring the aspherical mirror through this measurement dot matrix can effectively increase the number of sampling points in the edge region, thereby improving the measurement accuracy of the vertex curvature radius and solving the technical problem of reduced measurement accuracy caused by insufficient sampling points in the edge region.

[0038] Specifically, in step S103, through equipment such as a coordinate measuring machine, the measurement dot matrix is measured to obtain the position coordinates of each measurement point in the measurement dot matrix, obtaining measurement data corresponding to the measurement dot matrix. This measurement process does not require expensive laser trackers or profile measuring instruments, reducing the measurement cost and expanding the applicable scenarios.

[0039] Specifically, in step S104, using a local search algorithm, based on the measurement data, the actual aspherical vertex curvature radius of the aspherical mirror is calculated, including: Based on the measurement data, the nominal vertex curvature radius of the aspherical mirror at the vertex is fitted; Taking the nominal vertex curvature radius as the initial value, using the damped least squares method, the vertex curvature radius of the aspherical mirror is iterated to minimize the surface shape RMS value corresponding to the iterated vertex curvature radius, obtaining the actual aspherical vertex curvature radius of the aspherical mirror.

[0040] Specifically, in step S104, based on the measurement data, the nominal vertex curvature radius of the aspherical mirror at the vertex is fitted, including: Filter the measurement data to filter out the noise in the measurement data and obtain the filtered measurement data; Based on the filtered measurement data, fit to obtain the nominal vertex curvature radius of the aspherical mirror at the vertex.

[0041] In step S104, after obtaining the measurement data, a filtering method can be used to preprocess the measurement data. For example, the three-dimensional coordinate data measured by a coordinate measuring machine usually has noise interference. The three-dimensional coordinate data measured by the coordinate measuring machine is optimized and processed through filtering methods such as coordinate filtering to improve the accuracy and precision of the data. Through this method, the errors or interferences that may be generated due to the environment, measuring instruments, etc. in the measurement data can be eliminated, the noise component in the measurement data can be reduced, the rapid fluctuations and peaks in the measurement data can be removed, and the measurement data can be made smoother, thereby providing a more accurate data basis for subsequent fitting calculations.

[0042] After completing the filtering process, through a fitting method, the nominal vertex curvature radius of the aspherical mirror at the vertex is fitted. For example, fitting methods such as the least squares method are used, and the goal is to minimize the sum of the squares of the distances from the filtered measurement data points to the fitted aspherical model to solve for the nominal vertex curvature radius. Since the measurement data input into the fitting process has been filtered, the noise interference is reduced, so the obtained nominal vertex curvature radius is closer to the true value, and the measurement accuracy of the vertex curvature radius is improved.

[0043] In step S104, set the nominal vertex curvature radius as the initial value of the damped least squares method iteration. During the iteration process, the damped least squares method will gradually adjust the vertex curvature radius. After each adjustment, calculate the surface shape RMS error (surface shape RMS value) between the aspherical surface shape corresponding to the current vertex curvature radius and the measurement data. The goal of the iteration is to minimize this surface shape RMS error. Through continuous iteration, when the surface shape RMS error reaches the minimum, the vertex curvature radius at this time is the actual aspherical vertex curvature radius sought. This method uses the nominal vertex curvature radius as the iteration initial value, improves the iteration efficiency and accuracy, and through the optimization of the damped least squares method, a higher-precision actual aspherical vertex curvature radius can be obtained. Among them, the damped least squares method and the surface shape RMS value are prior arts and will not be elaborated here.

[0044] In some alternative embodiments, other existing local search algorithms, such as the hill climbing algorithm, simulated annealing algorithm, and tabu search algorithm, etc., can be used to calculate the actual aspherical vertex curvature radius, which will not be elaborated here.

[0045] Specifically, in step S104, after calculating the actual aspherical vertex curvature radius of the aspherical mirror based on the measurement data by using the local search algorithm, it further includes: Obtain the theoretical vertex curvature radius of the aspherical mirror, and adjust the processing parameters or processing strategy for machining the aspherical mirror according to the difference between the actual vertex curvature radius of the aspherical surface and the theoretical vertex curvature radius.

[0046] In step S104, the theoretical vertex curvature radius of the aspherical mirror can be obtained from the design drawing, product specification or CAD model. The theoretical vertex curvature radius represents the ideal designed value. Compare the actual vertex curvature radius with the theoretical vertex curvature radius, and calculate the difference between the two. This difference reflects the degree of machining deviation. According to this difference, adjust the processing parameters or processing strategy for machining the aspherical mirror. By adjusting the processing parameters or processing strategy for machining the aspherical mirror, the machining deviation can be corrected, and the machining accuracy and efficiency can be improved. Thus, the measurement results can be used to guide the subsequent machining process, and the optimization of the machining process can be realized.

[0047] As can be seen from the above, in this method for measuring the aspherical vertex curvature radius, by obtaining the dimensional data of the aspherical mirror, based on the dimensional data, combining the preset aspherical local sampling density calculation formula and the preset edge region encryption criterion, generating a measurement lattice, measuring the position coordinates of the measurement lattice, obtaining the measurement data corresponding to the measurement lattice, and using a local search algorithm, based on the measurement data, calculating the actual aspherical vertex curvature radius of the aspherical mirror; thus, through the local search algorithm, based on the measurement data corresponding to the measurement lattice generated by the preset aspherical local sampling density calculation formula and the preset edge region encryption criterion, calculating the actual aspherical vertex curvature radius of the aspherical mirror, solving the problems of the existing methods for measuring the aspherical vertex curvature radius, such as expensive measurement equipment, low measurement accuracy or limited applicable scenarios, etc. By quantitatively evaluating the sampling density and sampling position of the aspherical mirror, measuring the aspherical vertex curvature radius, and improving the measurement efficiency of the aspherical vertex curvature radius.

[0048] Reference Figure 2 , this application provides an apparatus for measuring the aspherical vertex curvature radius for measuring the aspherical vertex curvature radius, including: An acquisition module 1 for acquiring the dimensional data of the aspherical mirror; A generation module 2 for generating a measurement lattice according to the dimensional data, combining the preset aspherical local sampling density calculation formula and the preset edge region encryption criterion; A measurement module 3 for measuring the position coordinates of the measurement lattice to obtain the measurement data corresponding to the measurement lattice; A calculation module 4 for calculating the actual aspherical vertex curvature radius of the aspherical mirror by using a local search algorithm based on the measurement data.

[0049] The aspherical vertex curvature radius measuring device calculates the actual aspherical vertex curvature radius of the aspherical mirror based on the measurement data corresponding to the measurement lattice generated by a local search algorithm and based on a preset aspherical local sampling density calculation formula and a preset edge region encryption criterion, solving the problems of existing aspherical vertex curvature radius measurement methods, such as expensive measurement equipment, low measurement accuracy, or limited applicable scenarios. By quantitatively evaluating the sampling density and sampling position of the aspherical mirror, the aspherical vertex curvature radius is measured, improving the measurement efficiency of the aspherical vertex curvature radius.

[0050] Specifically, when the acquisition module 1 executes, it acquires the size data of the aspherical mirror. Among them, the size data includes data such as the theoretical surface shape, aperture, curvature radius, and sag height of the aspherical mirror, and these data can be obtained from design drawings or processing parameters.

[0051] Specifically, the preset aspherical local sampling density calculation formula includes a local sampling density calculation formula based on the curvature radius and a local sampling density calculation formula based on the sag height. When the generation module 2 generates the measurement lattice according to the size data, in combination with the preset aspherical local sampling density calculation formula and the preset edge region encryption criterion, it executes: According to the size data, in combination with the local sampling density calculation formula based on the curvature radius and the local sampling density calculation formula based on the sag height, calculate the sampling density of each position point of the aspherical mirror. Based on the sampling density and the preset edge region encryption criterion, generate the measurement lattice.

[0052] When the generation module 2 executes, by providing these two local sampling density calculation formulas based on the curvature radius and the sag height, the measurement method can be adapted to various types of aspherical mirrors. In the actual measurement process, using the local sampling density calculation formula based on the curvature radius and the local sampling density calculation formula based on the sag height to generate the sampling density of each position point of the aspherical mirror can ensure that the measurement lattice can fully reflect the surface shape characteristics of the aspherical mirror for different surface shape characteristics of the aspherical mirror, improving the measurement accuracy of the vertex curvature radius and the applicable range of the method.

[0053] Among them, the local sampling density calculation formula based on the curvature radius is specifically: ; Among them, is the sampling density of the position point in the aperture direction; is the curvature radius of the position point ; is the maximum curvature radius of the aspherical surface and the minimum curvature radius of the aspherical surface The median value of ; D is the aperture size of the aspherical mirror (if the shape of the aspherical mirror is rectangular, D represents the aperture size of the circumscribed circle of the rectangle); N is the influence function of the curvature radius sampling density, generally set to 30.

[0054] For the local sampling density calculation formula based on the curvature radius, the sampling density changes with the change of the surface curvature radius of the aspherical mirror. In the area where the curvature radius changes greatly, the sampling density is higher, and vice versa. Therefore, the measurement points can be more densely distributed in the area where the curvature changes violently, thus improving the measurement accuracy.

[0055] The specific local sampling density calculation formula based on the sagitta is: ; Among them, is the sampling density in the sagitta direction of the position point ; is the sagitta of the position point ; is the maximum sagitta of the aspherical surface and the minimum sagitta of the aspherical surface The median value of, that is ; M is the influence function of the sagitta sampling density. The influence function of the sagitta sampling density and the influence function of the curvature radius sampling density can be set to the same value, generally set to 30.

[0056] For the local sampling density calculation formula based on the sagitta, the sampling density changes with the change of the surface sagitta of the aspherical mirror. In the area where the sagitta changes greatly, the sampling density is higher, and vice versa. Therefore, the measurement points can be more densely distributed in the area where the aspherical height changes violently, ensuring the accuracy of the measurement.

[0057] Specifically, when the generation module 2 generates the measurement dot matrix based on the sampling density and the preset edge area encryption criterion, it executes: Generate a sampling dot matrix corresponding to the sampling density; Determine the area outside the maximum aperture area of the preset percentage in the aspherical mirror as the edge area; Based on the preset edge area encryption criterion, increase the number of sampling points for the sampling density of the sampling dot matrix located in the edge area to obtain the measurement dot matrix.

[0058] When the generation module 2 executes, based on the calculated sampling density value, in, by the ratio of the maximum aperture to the sampling density in the aperture direction and the ratio of the maximum sagitta to the sampling density in the sagitta direction The ratios are used to determine the distances of each sampling point in the aperture direction and the sagittal height direction respectively, generating an initial sampling dot matrix, which can initially ensure the sampling density on the surface of the aspherical mirror. To improve the measurement accuracy in the edge region, starting from the center point of the aperture of the aspherical mirror, determine the region outside the maximum aperture region at a preset percentage (the preset percentage can be set according to actual needs). The percentage maximum aperture region is the region within from the center point in the aperture direction, where n is the preset percentage), and the region outside this is defined as the edge region of the aspherical mirror, and the region within the preset percentage maximum aperture region is the central region. For example, if the set percentage is 80%, then starting from the center point of the aperture of the aspherical mirror, the region beyond the distance of 40% of the maximum aperture in the aperture direction is defined as the edge region. Then, according to the preset edge region encryption criterion, the sampling points in the edge region of the initial sampling dot matrix are encrypted (the sampling density is increased) to increase the number of sampling points in the edge region. For example, if the edge region encryption criterion is to increase the sampling point density in the edge region to 1.2 times, then sampling points are added in the edge region so that the sampling point density in the edge region is increased by 20% compared to the density of the initial sampling dot matrix, thus obtaining the final measurement dot matrix. Measuring the aspherical mirror through this measurement dot matrix can effectively increase the number of sampling points in the edge region, thereby improving the measurement accuracy of the vertex curvature radius and solving the technical problem of reduced measurement accuracy caused by insufficient sampling points in the edge region.

[0059] Specifically, when the measurement module 3 executes, it measures the measurement dot matrix through devices such as a coordinate measuring machine to obtain the position coordinates of each measurement point in the measurement dot matrix, and obtains the measurement data corresponding to the measurement dot matrix. This measurement process does not require expensive laser trackers or profile measuring instruments, reducing the measurement cost and expanding the applicable scenarios.

[0060] Specifically, when the calculation module 4 calculates the actual aspherical vertex curvature radius of the aspherical mirror based on the measurement data using the local search algorithm, it executes: Based on the measurement data, fit to obtain the nominal vertex curvature radius of the aspherical mirror at the vertex; Taking the nominal vertex curvature radius as the initial value, use the damped least squares method to iterate the vertex curvature radius of the aspherical mirror to minimize the surface shape RMS value corresponding to the iterated vertex curvature radius, and obtain the actual aspherical vertex curvature radius of the aspherical mirror.

[0061] Specifically, when the calculation module 4 fits to obtain the nominal vertex curvature radius of the aspherical mirror at the vertex based on the measurement data, it executes: Filter the measurement data to remove the noise in the measurement data and obtain the filtered measurement data; Based on the filtered measurement data, fit to obtain the nominal vertex curvature radius of the aspherical mirror at the vertex.

[0062] When the calculation module 4 is executed, after obtaining the measurement data, the filtering method can be used to preprocess the measurement data. For example, the three-dimensional coordinate data measured by a coordinate measuring machine usually has noise interference. The three-dimensional coordinate data measured by the coordinate measuring machine is optimized and processed through filtering methods such as coordinate filtering to improve the accuracy and precision of the data. Through this method, the errors or interferences that may be generated due to the environment, measuring instruments, etc. in the measurement data can be eliminated, the noise component in the measurement data can be reduced, the rapid fluctuations and peaks in the measurement data can be removed, and the measurement data can be made smoother, thereby providing a more accurate data basis for subsequent fitting calculations.

[0063] After completing the filtering process, through the fitting method, the nominal vertex curvature radius of the aspherical mirror at the vertex is obtained by fitting. For example, fitting methods such as the least squares method are used, and the goal is to minimize the sum of the squares of the distances from the filtered measurement data points to the fitted aspherical model, and the nominal vertex curvature radius is obtained by solving. Since the measurement data input into the fitting process has been filtered, the noise interference is reduced, so the obtained nominal vertex curvature radius is closer to the true value, and the measurement accuracy of the vertex curvature radius is improved.

[0064] When the calculation module 4 is executed, the nominal vertex curvature radius is set as the initial value of the damped least squares method iteration. During the iteration process, the damped least squares method will gradually adjust the vertex curvature radius. After each adjustment, calculate the surface RMS error (surface RMS value) between the aspherical surface shape corresponding to the current vertex curvature radius and the measurement data. The goal of the iteration is to minimize this surface RMS error. Through continuous iteration, when the surface RMS error reaches the minimum, the vertex curvature radius at this time is the actual aspherical vertex curvature radius sought. This method uses the nominal vertex curvature radius as the iteration initial value, improves the iteration efficiency and accuracy, and can obtain a higher-precision actual aspherical vertex curvature radius through the optimization of the damped least squares method. Among them, the damped least squares method and the surface RMS value are existing technologies and will not be elaborated here.

[0065] In some alternative embodiments, other existing local search algorithms such as the hill climbing algorithm, simulated annealing algorithm, and tabu search algorithm can be used to calculate the actual aspherical vertex curvature radius, which will not be elaborated here.

[0066] Specifically, the aspherical vertex curvature radius measuring device further includes: An adjustment module is used to obtain the theoretical vertex curvature radius of the aspherical mirror, and adjust the processing parameters or processing strategies for machining the aspherical mirror according to the difference between the actual vertex curvature radius and the theoretical vertex curvature radius of the aspherical mirror.

[0067] After obtaining the actual vertex curvature radius of the aspherical mirror, the adjustment module can obtain the theoretical vertex curvature radius of the aspherical mirror from the design drawing, product manual or CAD model. The theoretical vertex curvature radius represents the ideal designed value. Compare the actual vertex curvature radius with the theoretical vertex curvature radius, and calculate the difference between the two. This difference reflects the degree of machining deviation. According to this difference, adjust the processing parameters or processing strategies for machining the aspherical mirror. By adjusting the processing parameters or processing strategies for machining the aspherical mirror, the machining deviation can be corrected, and the machining accuracy and efficiency can be improved. Thus, the measurement results can be used to guide the subsequent machining process, and the optimization of the machining process can be realized.

[0068] As can be seen from the above, the measurement device for the aspherical vertex curvature radius obtains the dimensional data of the aspherical mirror, generates a measurement lattice according to the dimensional data, in combination with a preset aspherical local sampling density calculation formula and a preset edge region encryption criterion, measures the position coordinates of the measurement lattice, obtains measurement data corresponding to the measurement lattice, and uses a local search algorithm to calculate the actual aspherical vertex curvature radius of the aspherical mirror based on the measurement data; thus, through the local search algorithm, based on the measurement data corresponding to the measurement lattice generated by the preset aspherical local sampling density calculation formula and the preset edge region encryption criterion, calculates the actual aspherical vertex curvature radius of the aspherical mirror, solves the problems of the existing measurement methods for the aspherical vertex curvature radius, such as expensive measurement equipment, low measurement accuracy or limited applicable scenarios, measures the aspherical vertex curvature radius by quantitatively evaluating the sampling density and sampling position of the aspherical mirror, and improves the measurement efficiency of the aspherical vertex curvature radius.

[0069] Please refer to Figure 3 , Figure 3A schematic structural diagram of an electronic device provided by an embodiment of the present application. The present application provides an electronic device, including: a processor 301 and a memory 302. The processor 301 and the memory 302 are interconnected and communicate with each other through a communication bus 303 and / or other forms of connection mechanisms (not marked). The memory 302 stores a computer program executable by the processor 301. When the electronic device runs, the processor 301 executes the computer program to perform the aspherical vertex curvature radius measurement method in any optional implementation manner of the above embodiment, so as to implement the following functions: obtaining size data of an aspherical mirror, generating a measurement lattice according to the size data in combination with a preset aspherical local sampling density calculation formula and a preset edge region encryption criterion, measuring the position coordinates of the measurement lattice, obtaining measurement data corresponding to the measurement lattice, and using a local search algorithm to calculate the actual aspherical vertex curvature radius of the aspherical mirror based on the measurement data.

[0070] An embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it performs the aspherical vertex curvature radius measurement method in any optional implementation manner of the above embodiment, so as to implement the following functions: obtaining size data of an aspherical mirror, generating a measurement lattice according to the size data in combination with a preset aspherical local sampling density calculation formula and a preset edge region encryption criterion, measuring the position coordinates of the measurement lattice, obtaining measurement data corresponding to the measurement lattice, and using a local search algorithm to calculate the actual aspherical vertex curvature radius of the aspherical mirror based on the measurement data. Wherein, the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (Static Random Access Memory, abbreviated as SRAM), electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, abbreviated as EEPROM), erasable programmable read-only memory (Erasable Programmable Read Only Memory, abbreviated as EPROM), programmable read-only memory (Programmable Red-Only Memory, abbreviated as PROM), read-only memory (Read-Only Memory, abbreviated as ROM), magnetic memory, flash memory, a magnetic disk or an optical disc.

[0071] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For another example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some communication interfaces. The indirect coupling or communication connection of the devices or units can be in electrical, mechanical or other forms.

[0072] In addition, the units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units. They can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0073] Furthermore, in each embodiment of the present application, the functional modules can be integrated together to form an independent part, or each module can exist alone, or two or more modules can be integrated to form an independent part.

[0074] In this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0075] The above description is only for the embodiments of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for measuring the curvature radius of an aspherical vertex, for measuring the curvature radius of an aspherical vertex, characterized in that: Includes steps: Get the size data of the aspheric mirror; Generate a measurement point array based on the size data, in combination with a preset aspheric local sampling density calculation formula and a preset edge area encryption criterion; Measuring the position coordinates of the measurement point array to obtain measurement data corresponding to the measurement point array; The actual aspheric vertex curvature radius of the aspheric reflector is calculated based on the measurement data using a local search algorithm.

2. The method for measuring the vertex curvature radius of an aspherical surface according to claim 1, characterized in that: The preset aspheric local sampling density calculation formula includes a local sampling density calculation formula based on curvature radius and a local sampling density calculation formula based on vector height.

3. The method for measuring the vertex curvature radius of an aspherical surface according to claim 2, characterized in that: According to the size data, combined with a preset aspheric local sampling density calculation formula and a preset edge area encryption criterion, a measurement point matrix is ​​generated, including: According to the size data, in combination with the local sampling density calculation formula based on the curvature radius and the local sampling density calculation formula based on the vector height, the sampling density of each position point of the aspheric reflector is calculated; Based on the sampling density and the preset edge area encryption criterion, a measurement point matrix is ​​generated.

4. The method for measuring the vertex curvature radius of an aspherical surface according to claim 3, characterized in that: Based on the sampling density and the preset edge area encryption criterion, a measurement point matrix is ​​generated, including: Generating a sampling point matrix corresponding to the sampling density; Determining, in the aspherical reflector, an area outside a preset percentage of the maximum aperture area as an edge area; Based on the preset edge area encryption criterion, the number of sampling points is increased for the sampling density located in the edge area in the sampling point matrix to obtain a measurement point matrix.

5. The method for measuring the vertex curvature radius of an aspherical surface according to claim 1, characterized in that: The actual aspheric vertex curvature radius of the aspheric reflector is calculated based on the measurement data using a local search algorithm, including: Based on the measurement data, fitting is performed to obtain a nominal vertex curvature radius of the aspheric reflector at the vertex; The nominal vertex curvature radius is used as an initial value, and the damped least squares method is used to iterate the vertex curvature radius of the aspheric reflector, so that the surface shape RMS value corresponding to the iterated vertex curvature radius is minimized, thereby obtaining the actual aspheric vertex curvature radius of the aspheric reflector.

6. The method for measuring the vertex curvature radius of an aspherical surface according to claim 5, characterized in that: Based on the measurement data, the nominal vertex curvature radius of the aspheric reflector at the vertex is obtained by fitting, including: Performing filtering on the measurement data to filter out noise in the measurement data to obtain filtered measurement data; Based on the filtered measurement data, the nominal vertex curvature radius of the aspheric reflector at the vertex is obtained by fitting.

7. The method for measuring the vertex curvature radius of an aspherical surface according to claim 1, characterized in that: After calculating the actual aspheric vertex curvature radius of the aspheric reflector based on the measurement data using a local search algorithm, the method further includes: The theoretical vertex curvature radius of the aspheric reflector is obtained, and according to the difference between the actual aspheric vertex curvature radius and the theoretical vertex curvature radius, the processing parameters or processing strategy of the aspheric reflector are adjusted.

8. A device for measuring the curvature radius of an aspherical vertex, used for measuring the curvature radius of an aspherical vertex, characterized in that: include: An acquisition module, used for acquiring the size data of the aspheric reflector; A generation module, used to generate a measurement point array according to the size data, in combination with a preset aspheric local sampling density calculation formula and a preset edge area encryption criterion; A measuring module, used to measure the position coordinates of the measuring point array to obtain measurement data corresponding to the measuring point array; The calculation module is used to calculate the actual aspheric vertex curvature radius of the aspheric reflector based on the measurement data by using a local search algorithm.

9. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the memory stores a computer program executable by the processor, and when the processor executes the computer program, the steps in the method for measuring the vertex curvature radius of an aspherical surface as described in any one of claims 1 to 7 are executed.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for measuring the vertex curvature radius of an aspherical surface as claimed in any one of claims 1 to 7 are executed.

Images