Surface type detection method and system

Abstract

The invention relates to the technical field of optical detection, and provides a surface type detection method and system, and the method comprises the steps: controlling a surface type detection system to output a detection light beam matched with a current detection mode according to the current detection mode; obtaining an interference light beam returned after the detection light beam is transmitted in the detection light path and carries phase information of the to-be-detected element; and determining surface type data corresponding to the to-be-measured element according to the interference light beam. According to the detection light beam corresponding to the current detection mode corresponding to the current detection requirement, the limitation that a traditional interferometer can only provide a single fixed-form light beam is broken through, and detection conditions of to-be-detected elements with different structural characteristics can be flexibly adapted; the source matching strategy ensures that the return detection light beam bearing effective phase information can still be received even under a complex or non-standard light path condition, so that the signal-to-noise ratio and the contrast ratio of an original interference signal are fundamentally optimized, and the data precision and the system universality of surface type detection are remarkably improved.

Description

Technical Field

[0001] This application relates to the field of optical inspection technology, and in particular to a surface shape inspection method and system. Background Technology

[0002] Conical optical elements (such as aircraft nose cones and laser system conical mirrors) are widely used in aerospace and high-energy laser fields due to their special aerodynamic shape or beam shaping function. These elements typically have steep, large-aperture, and rotationally symmetrical geometric features, and their surface accuracy directly affects the imaging quality or beam transmission quality.

[0003] Because the upper and lower parts of products with similar cone-shaped optical elements are obstructed, the test data is incomplete, which poses a technical test difficulty, and there is currently no relevant test technology guidance. Summary of the Invention

[0004] In view of this, embodiments of this application provide a surface shape detection method and system to solve the problem that the prior art cannot perform surface shape detection on conical optical elements.

[0005] A first aspect of this application provides a surface shape detection method, the method comprising: controlling a surface shape detection system to output a detection beam that matches the current detection mode according to a current detection mode; acquiring an interference beam that returns after the detection beam has been transmitted in the detection optical path and carries the phase information of the element under test; and determining the surface shape data corresponding to the element under test based on the interference beam. A second aspect of this application provides a surface shape detection system, which includes an interferometer and a design lens, and the surface shape detection system is used in the steps of the above method.

[0006] A third aspect of this application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described method.

[0007] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the above-described method.

[0008] The beneficial effects of this application embodiment compared with the prior art are as follows: The method in this application embodiment controls the surface shape detection system to output a detection beam that matches the current detection mode according to the current detection mode; acquires the interference beam that returns after the detection beam has transmitted in the detection optical path and carried the phase information of the element under test; and determines the surface shape data corresponding to the element under test based on the interference beam. This application, by using the detection beam corresponding to the current detection mode corresponding to the current detection requirements, breaks through the limitation of traditional interferometers that can only provide a single fixed beam type, and can flexibly adapt to the detection conditions of elements under test with different structural features. This source matching strategy ensures that even under complex or non-standard optical path conditions, the return detection beam carrying effective phase information can still be received, thereby fundamentally optimizing the signal-to-noise ratio and contrast of the original interference signal, significantly improving the data accuracy and system versatility of surface shape detection, and avoiding the problem in related technologies that cannot perform surface shape detection on conical optical elements. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic flowchart of a face shape detection method provided in an embodiment of this application; Figure 2 This is a schematic flowchart of another face shape detection method provided in an embodiment of this application; Figure 3 This is a schematic diagram of a flipping vehicle stack provided in an embodiment of this application. Detailed Implementation

[0011] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0012] A face shape detection method and system according to an embodiment of this application will now be described in detail with reference to the accompanying drawings.

[0013] Figure 1 This is a flowchart illustrating a face shape detection method provided in an embodiment of this application, as shown below. Figure 1 As shown, the method includes: S101. Based on the current detection mode, control the surface detection system to output a detection beam that matches the current detection mode; Understandably, a surface profile inspection system primarily consists of an interferometer (providing the light source and imaging detector) and a design lens (used for beam shaping and transmission). The inspection modes include at least two types: the first is a spatial splitting mode for physical beam splitting scenarios, and the second is a wavelength-tuned tomography mode for tomographic scanning scenarios. The surface profile inspection system can automatically switch inspection modes based on user input commands or the type of the component under test.

[0014] In some examples, if the current detection mode is spatial splitting mode, the initial beam output by the surface detection system is spatially divided into multiple detection beams corresponding to different transmission paths using a multi-channel beam transmission component in the surface detection system. These multiple detection beams are then spatially combined to form a conical detection beam that matches the component under test (DUT). Specifically, the control process involves using a multi-channel beam transmission component to physically divide the initial beam output by the interferometer (usually a collimated plane wave) into multiple detection beams corresponding to different transmission paths. Further, by adjusting the projection angle of each detection beam, they are spatially combined to form a conical detection beam. The overall envelope shape of this conical detection beam matches the cone angle geometry of the DUT (conical part), thus enabling simultaneous or partial coverage of all sides of the DUT.

[0015] In some examples, if the current detection mode is wavelength-tuned tomography detection mode, the optical path distance of the current target sub-surface in the element under test (DUT) relative to the surface profile detection system is obtained. Based on the optical path distance, the target wavelength parameter is determined, and the tunable light source in the surface profile detection system is controlled to output a detection beam that conforms to the target wavelength parameter. For example, if the DUT includes the front and rear surfaces of a first window mirror, or a stepped surface at a specific depth, when the front surface of the first window mirror is taken as the current target sub-surface, the system first reads or detects the first optical path distance (L1) of that front surface relative to the interferometer host. This is based on the interferometric detection principle (e.g., phase-shifting interference principle, phase shift amount). With optical path length L and wavelength change Related: ), calculate the amount of preset phase shift (e.g., at the first optical path distance L1) to generate the desired phase shift. The first wavelength tuning step size required (step size) At this time, control the output wavelength of the tunable light source according to... The detection beam that performs stepping or scanning causes the signal reflected from the front surface to form effective analytical fringes, while the signal reflected from surfaces at other distances (such as the rear surface) is suppressed or filtered out in subsequent algorithms because it does not meet the phase shift condition.

[0016] Accordingly, when switching to use the rear surface of the first window mirror as the current target sub-surface, the second optical path distance (L2) of this rear surface relative to the interferometer host is obtained (obviously). Based on this, recalculate and Matching second wavelength tuning step size ( ), and control the output wavelength of the tunable light source according to The changing detection beam.

[0017] By employing this targeted output strategy of "one distance, one wavelength (parameter)," the surface inspection system can achieve precise tomographic detection of different depths of a conical transparent component without moving any mechanical parts, simply by changing the wavelength scanning characteristics of the output beam. This method of adaptively adjusting the output beam wavelength parameter based on distance enables non-contact tomographic detection of multiple layers on the surface of a transparent conical test element.

[0018] S102. Acquire the interference beam that returns after the detection beam has been transmitted in the detection optical path and carries the phase information of the device under test; The interaction mechanism between the detection beam and the device under test differs under different detection modes, and therefore the way to obtain the interference beam also differs.

[0019] Specifically, for the spatial splitting mode: This mode employs a transmissive folding optical path for detection. Understandably, to achieve a closed-loop optical path, a mirror assembly is placed behind the device under test (DUT) (i.e., on the side facing away from the surface detection system). This mirror assembly contains multiple reflecting units (such as planar high-reflectivity mirrors) that correspond one-to-one with the detection beam. The reflection angle of the mirror assembly has a strict correspondence with the incident direction of the detection beam. Specifically, since the detection beam reaches the mirror assembly after being transmitted through the DUT, the spatial orientation of each reflecting unit in the mirror assembly needs to be pre-adjusted so that its mirror normal is parallel to the propagation direction of the beam after passing through the DUT (i.e., achieving self-collimation). This ensures that the detection beam, after passing through the DUT, is perpendicularly incident on the mirror surface and reflected along the original optical path.

[0020] This application receives a test beam reflected back by a mirror assembly and then transmitted again through the element under test (DUT). Because the test beam passes through the corresponding region of the DUT twice during its round trip, its wavefront distortion accumulates twice the phase information of the DUT (such as material homogeneity, thickness variation, or transmission wavefront error). The test beam eventually returns to the surface profile detection system and superimposes with a reference beam to form an interference beam.

[0021] It is understandable that the reference beam is a reference beam formed by direct reflection from the reference surface of the design lens (or standard lens) in the surface profile detection system.

[0022] Specifically, before the test beam is projected onto the device under test (DUT), some of the light energy is directly reflected by the reference surface (usually a standard plane or sphere with high-precision surface data) when it passes through the standard reference mirror, and returns to the interferometer along the original optical path. This reference beam has a known ideal wavefront (such as an ideal plane wavefront) and does not pass through the DUT during transmission, therefore it does not contain the phase information of the DUT, and thus serves as a standard reference for phase comparison with the test beam in interferometric testing.

[0023] For wavelength-tuned tomography, this mode employs a direct reflection optical path for detection. There is no need to place a reflector assembly behind the device under test (DUT); the surface profile inspection system directly utilizes the DUT's own surface as a reflection reference.

[0024] This application receives a test beam directly reflected from the current target sub-surface and returning along the original optical path, causing the test beam to superimpose with a reference beam to form an interference beam carrying specific phase information of the current target sub-surface. Specifically, since the device under test (DUT) is typically made of transparent material, when the detection beam is projected onto the DUT, the beam undergoes Fresnel reflection at interfaces at different depths. Therefore, the test beam returning to the surface profile detection system actually contains a superimposed optical field of multiple reflected wavefronts from surfaces at different depths.

[0025] When the superimposed optical field and the reference beam are superimposed within the interferometer, according to the two-beam interference principle, the phase change of the interference signal depends on the relationship between the optical path difference and the wavelength. Since this application controls the scanning (or stepping) of the light source wavelength over time in step S101, and the optical path difference (OPD) relative to the interferometer reference mirror differs significantly between sub-surfaces at different depths (e.g., the front and rear surfaces): The reflected light component from the "current target sub-surface": Since its optical path distance matches the target wavelength parameters (such as scanning step size or tuning range) set in S101, it will form an effective interference signal with a specific carrier frequency or a specific phase shift law after being superimposed with the reference light.

[0026] Reflected light components from other "non-target sub-surfaces": Due to the mismatch between their optical path distance and the current setting parameters, the frequency of their interference signals differs significantly from that of the target signal, or their fringe contrast is severely suppressed due to exceeding the coherence length.

[0027] Therefore, although the physical light field received is superimposed, at the signal level, the interfering beam mainly carries (or highlights) the phase information of the current target sub-surface, while the reflection information of other surfaces is manifested as separable high-frequency / low-frequency noise or DC background.

[0028] S103. Determine the surface profile data of the component under test based on the interference beam.

[0029] As mentioned earlier, since the physical properties of the interference beams acquired under different detection modes are different (one is a spatially distributed sub-aperture image, and the other is a time-varying tomographic signal), the methods for determining the surface profile data of the element under test based on the interference beams are also different.

[0030] Specifically, for the interference beams obtained in the spatial splitting mode, firstly, phase analysis and phase demodulation are performed on the interference beams returning through different sub-regions (such as using phase shift algorithm or carrier fringe analysis method), and the local phase data corresponding to each detection beam is calculated and converted into local surface data. Subsequently, based on the preset spatial geometric parameters of the multi-channel beam transmission assembly and the mirror assembly, a unified coordinate system for the entire aperture of the component under test is constructed. Finally, the various dispersed local surface profile data are mapped into this unified coordinate system. Pose correction is performed using the overlap data between adjacent sub-regions, or multiple local surface profile data are fused using a stitching algorithm based directly on the coordinate positions calibrated by the system, thereby reconstructing the complete conical composite surface profile data of the component under test.

[0031] Specifically, for wavelength-tuned tomography, the time-varying interference signal generated by the change of the interference beam with wavelength scanning is first acquired. Then, frequency domain analysis and demodulation processing are performed on this time-varying signal. In one specific embodiment, a Fast Fourier Transform (FFT) is used to convert the time-domain signal into a frequency-domain signal. In the frequency domain, because the optical path difference between surfaces at different depths (such as the front and rear surfaces of the first window mirror) and the interferometer is different, the corresponding interference signal carrier frequencies are also different. Therefore, the processing unit can separate the specific spectral peaks corresponding to the current target sub-surface and filter out interference signals (i.e., noise) from other surfaces. Subsequently, using the separated spectral information, the discrete phase data of the target sub-surface is calculated through inverse Fourier transform or phase extraction algorithms.

[0032] Finally, 3D coordinate reconstruction and surface fitting are performed. The 3D coordinate information of the effective pixels in the discrete phase data is obtained (e.g., generating a .dat point cloud file containing X, Y, and Z coordinates). Based on the theoretical geometric model of the component under test (e.g., the equation of a conic surface), surface fitting is performed on the extracted massive point cloud data using the least squares method or the Zernike polynomial fitting algorithm. Through these steps, the layered local surface features of each surface of the component under test can be reconstructed, and finally, high-precision integrated 3D surface feature data after removing parasitic interference noise is obtained.

[0033] According to the solution provided in the embodiments of this application, the surface shape detection system outputs a detection beam that matches the current detection mode; the interference beam returned after the detection beam has transmitted in the detection optical path and carried the phase information of the component under test; and the surface shape data corresponding to the component under test is determined based on the interference beam. This application, by using a detection beam corresponding to the current detection mode corresponding to the current detection requirements, overcomes the limitation of traditional interferometers that can only provide a single fixed beam type, and can flexibly adapt to the detection conditions of components under test with different structural features. This source matching strategy ensures that even under complex or non-standard optical path conditions, a return detection beam carrying effective phase information can still be received, thereby fundamentally optimizing the signal-to-noise ratio and contrast of the original interference signal, significantly improving the data accuracy and system versatility of surface shape detection, and avoiding the problem in related technologies where surface shape detection of conical optical components is impossible.

[0034] 1. Existing interferometers typically output beams of a fixed form (such as standard plane waves or spherical waves), making them difficult to directly adapt to the detection requirements of special structural components (such as steeply angled components or multilayer components). The method in this application can actively adjust the physical properties (such as spatial distribution or spectral characteristics) of the output beam according to different detection modes (i.e., for different characteristics of the object under test), achieving optimal matching with the current detection task. This design allows a single detection method to flexibly adapt to various complex detection scenarios, greatly expanding the application scope of interferometric detection.

[0035] 2. This application optimizes the acquisition quality of interference signals and improves the accuracy of surface data resolution. By outputting a detection beam that "matches" the detection mode, it ensures that the beam is in an ideal physical state when interacting with the device under test (e.g., ensuring the light returns along its original path or maximizing the contrast of interference fringes). Compared to forced detection using a mismatched universal beam, this method can acquire an interference beam with higher signal-to-noise ratio (SNR) and higher contrast from the source, thereby providing a high-quality raw signal for subsequent data processing, significantly reducing phase calculation errors, and improving the accuracy of the final surface data reconstruction.

[0036] 3. Effective signal extraction under complex optical paths is achieved. This application constructs a complete signal closed loop by "acquiring the interference beam that returns after transmitting and carrying phase information in the detection optical path". Whether through special optical path folding or specific signal filtering, this method can ensure that even when the structure of the device under test is complex (making it difficult for the optical path to return directly), it can still stably acquire an effective signal containing the surface shape information of the device under test, solving the technical problem that special devices cannot form resolvable interference fringes.

[0037] For the hardware and optical path design of the "spatial splitting mode," mechanical errors are eliminated, enabling static full-aperture inspection: By employing a multi-channel beam transmission component to shape the beam into a conical inspection beam adapted to the geometry of the component under test (DUT), this application can cover steep conical sides in one go or in sections without requiring any mechanical rotation of the DUT or interferometer. This fundamentally eliminates the systematic errors introduced by mechanical shaft wobble, eccentricity, or positioning deviations in traditional methods, significantly improving the geometric accuracy of full-aperture inspection.

[0038] By constructing a dual-path optical system where the beam is transmitted through the reflector of the element under test (DUT), reflected, and then transmitted back through the DUT, the detection beam passes through the sidewall of the DUT twice during its round trip. This means that the phase change carried in the interference fringes is twice the amount of the actual material defects or surface errors of the DUT. This design significantly improves the system's sensitivity to minute changes in refractive index or thickness inhomogeneities, making it particularly suitable for the transmission wavefront quality testing of high-precision optical radomes.

[0039] For the light source control of the "wavelength-tuned tomography mode," precise tomography capability and signal-to-noise ratio optimization are achieved through a control strategy that "determines the matching wavelength parameters by obtaining the optical path distance of the target sub-surface," and can "customize" interference conditions for specific detection depths. This mechanism ensures that only the reflected light from the current target sub-surface forms high-contrast effective interference fringes with the reference light, while reflected light from other surfaces (such as non-detection surfaces) is naturally suppressed because it does not meet the coherence or phase-shifting conditions. This effectively solves the problem of parasitic interference fringes (Ghost Fringes) commonly found in the inspection of transparent parts, eliminating the need to apply Vaseline or matting agents to non-detection surfaces, and achieving non-destructive and pollution-free inspection.

[0040] High-precision full-aperture reconstruction (spatial splitting mode) for data processing algorithms under different modes: By constructing a unified coordinate system for the entire aperture and performing sub-aperture stitching processing, this application can fuse multiple spatially dispersed local surface data into a single continuous surface. This method effectively compensates for the relative positional errors between sub-apertures through the calculation of overlapping areas or the constraints of system calibration parameters, thereby obtaining comprehensive data that truly reflects the overall morphology of the tapered part.

[0041] Frequency domain signal separation and denoising (for wavelength-tuned tomography): By performing frequency domain analysis (such as FFT) and multi-surface fitting on the time-series interferometric signal, the mixed and superimposed optical field signals can be mathematically separated in the frequency domain at the data processing level. This not only allows for the simultaneous acquisition of surface shape data of the front and rear surfaces, but also enables the simultaneous calculation of the component's thickness distribution data, greatly improving the energy efficiency and data richness of a single detection.

[0042] To better understand this application, this embodiment provides a more specific example for illustration.

[0043] like Figure 2 As shown, the interferometer lens is modified to form a multi-channel lens composed of three sets of plane standard mirrors. When testing the full-aperture composite surface profile of a conical part, mirror 1 is placed under the path of beam 1 through the conical part under test, and the optical path is adjusted to achieve collimation, thus achieving the data acquisition state of the composite surface profile under the aperture of beam 1; mirror 2 is placed under the path of beam 2 through the conical part under test, and the optical path is adjusted to achieve collimation, thus achieving the data acquisition state of the composite surface profile under the aperture of beam 2; mirror 2 is placed under the path of beam 3 through the conical part under test, and the optical path is adjusted to achieve collimation, thus achieving the data acquisition state of the composite surface profile under the aperture of beam 3. After the optical path adjustment is completed, the interferometer detects the data, realizes the output of the conical beam, and completes the full-aperture composite surface profile detection of the conical part.

[0044] like Figure 3 As shown, a wavelength-tuned interferometer serves as the output light source. During the detection process, the wavelength is adjusted to detect the surface shape of each facet of the product under test. Beam 1 detects the front surface of window mirror 2, forming a set of surface shape data; beam 4 detects the rear surface of window mirror 2, forming a set of surface shape data; beam 2 detects the front surface of window mirror 1, forming a set of surface shape data; beam 3 detects the rear surface of window mirror 1, forming a set of surface shape data. The surface shape of each facet is processed by interferometer software to form a composite surface shape of the four faces, or MATLAB software is used to process the .dat (coordinate points / pixels) of each facet to form a composite coordinate point / pixel point, and the composite surface shape is fitted.

[0045] All of the above-mentioned optional technical solutions can be combined in any way to form the optional embodiments of this application, and will not be described in detail here.

[0046] The following are embodiments of the apparatus described in this application, which can be used to execute the embodiments of the method described in this application. For details not disclosed in the apparatus embodiments of this application, please refer to the embodiments of the method described in this application.

[0047] This embodiment also provides a surface shape detection system, which includes an interferometer and a design lens. The surface shape detection system is used to perform the steps of the method in any of the above embodiments.

[0048] In some examples, the system also includes a reflector positioned on the side of the element under test facing away from the interferometer.

[0049] In some examples, the lens design utilizes a multi-channel beam transmission component in an interferometer to spatially divide the initial beam output by the surface detection system into multiple detection beams corresponding to different transmission paths. These multiple detection beams are then spatially combined to form a conical detection beam that matches the element under test.

[0050] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0051] If an integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program may include computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. A computer-readable medium may include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in a computer-readable medium can be appropriately added to or subtracted according to the requirements of legislation and patent practice in a jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0052] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A surface shape detection method, characterized in that, The method includes: Based on the current detection mode, the control surface detection system outputs a detection beam that matches the current detection mode; The interference beam that returns after the detection beam has been transmitted in the detection optical path and carries the phase information of the device under test is obtained; Based on the interference beam, the surface profile data corresponding to the element under test is determined.

2. The method according to claim 1, characterized in that, Based on the current detection mode, the control surface detection system outputs a detection beam that matches the current detection mode, including: If the current detection mode is spatial splitting mode, the initial beam output by the surface detection system is spatially divided into multiple detection beams corresponding to different transmission paths using the multi-channel beam transmission component of the surface detection system. The multiple detection beams are spatially combined to form a conical detection beam that matches the element under test.

3. The method according to claim 2, characterized in that, Acquiring the interference beam that returns after the detection beam has been transmitted in the detection optical path and carries the phase information of the device under test, includes: The test beam, which is reflected back from the reflector assembly to the surface detection system via the element under test, is received and superimposed with the reference beam to form the interference beam.

4. The method according to claim 1, characterized in that, Based on the current detection mode, the control surface detection system outputs a detection beam that matches the current detection mode, including: If the current detection mode is wavelength tuned tomography detection mode, obtain the optical path distance of the current target sub-surface in the element under test relative to the surface detection system; Based on the optical path distance, the target wavelength parameter is determined, and the tunable light source in the surface detection system is controlled to output the detection beam that conforms to the target wavelength parameter.

5. The method according to claim 4, characterized in that, Acquiring the interference beam that returns after the detection beam has been transmitted in the detection optical path and carries the phase information of the device under test, includes: The test beam, which is directly reflected from the current target sub-surface and returns along the original optical path, is received, and the test beam is superimposed with the reference beam to form the interference beam carrying specific phase information of the current target sub-surface.

6. The method according to any one of claims 1-3, characterized in that, Based on the interference beam, the surface profile data corresponding to the element under test is determined, including: Phase analysis is performed on the interference beams returning from different sub-regions to obtain local surface data corresponding to each interference beam speed; Based on the spatial geometric parameters of the surface detection system, a unified coordinate system for the entire aperture of the component under test is constructed. The local surface data is mapped to the full-caliber unified coordinate system, and the overlapping data of adjacent sub-regions or a preset stitching algorithm are used to synthesize the complete surface data of the component under test from multiple local surface data.

7. The method according to any one of claims 1, 4, and 5, characterized in that, Based on the interference beam, the surface profile data corresponding to the element under test is determined, including: The interference beams acquired under different wavelength parameters are demodulated to extract discrete phase data of different target sub-surfaces of the element under test. Obtain the three-dimensional coordinate information of the effective pixels in the discrete phase data; Based on the theoretical geometric model of the component under test, multi-surface fitting is performed on the three-dimensional coordinate information to reconstruct the comprehensive three-dimensional surface data of the component under test.

8. A surface shape detection system, characterized in that, The system includes: an interferometer and a design lens, wherein the surface detection system is used to perform the steps of the method as described in any one of claims 1-7.

9. The surface shape detection system according to claim 8, characterized in that, The system further includes a reflector, which is disposed on the side of the element under test facing away from the interferometer.

10. The surface shape detection system according to claim 8, characterized in that, The designed lens is used to spatially divide the initial beam output by the surface detection system into multiple detection beams corresponding to different transmission paths using the multi-channel beam transmission component in the interferometer. The multiple detection beams are spatially combined to form a conical detection beam that matches the element under test.

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