A method for correcting measurement errors of a multi-wavelength synthetic dynamic interferometer

Abstract

The application relates to a method for correcting measurement errors of a multi-wavelength synthetic dynamic interferometer, and relates to the field of interferometer measurement technology, and comprises the following steps: S1, making the fringe contrast of interference light fields of a first laser and a second laser greater than a contrast threshold; S2, collecting a parasitic interference image and designing a band-stop filter; S3, collecting a test sample image by taking the first laser as a light source and recording wavelength information of the first laser; collecting a test sample image by taking the second laser as a light source and recording wavelength information of the second laser; S4, obtaining and through the band-stop filter in the step S2; S5, obtaining a minimum circumscribed circle of an effective area in and a minimum circumscribed circle of the effective area in, and correcting the minimum circumscribed circle of the effective area in and the minimum circumscribed circle of the effective area in by taking as a reference pair to obtain a final effective area M; and S6, performing unpacking calculation on the final effective area M.

Description

Technical Field

[0001] This application relates to the field of interferometer measurement technology, and in particular to a method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer. Background Technology

[0002] As the demands for telescope resolution in astronomy, optics, and other fields continue to increase, the aperture of telescopes needs to be continuously enlarged. However, the design, fabrication, and testing of large-aperture mirrors are extremely challenging. Therefore, modular mirrors, which are not limited by size, have become one of the important methods for manufacturing large-aperture astronomical telescopes. The surface shape and resolution of a modular mirror are affected by the translational errors between its sub-mirrors.

[0003] For detecting pinpoint translation errors in optical components, single-wavelength interferometers are limited by 2pi ambiguity, with a measurement range typically on the order of hundreds of nanometers, limited to half the measurement wavelength. Furthermore, traditional mechanical or wavelength phase shifting methods require lengthy measurements, and the results are susceptible to environmental disturbances. Therefore, a method based on a multi-wavelength synthetic dynamic interferometer is proposed for detecting translation errors. Multi-wavelength synthesis extends the measurement wavelength to the μm and mm levels, increasing the detection range; dynamic interferometry acquires all interference information within a single frame, significantly reducing measurement time and improving the interferometer's detection accuracy.

[0004] The multi-wavelength synthetic dynamic interferometer measurement system mainly consists of a light source module, a Thyman-Green optical path module, and a polarization interferometer module. The polarization interferometer module is divided into a microlens array, a polarizer array, and a CMOS array, with three layers corresponding one-to-one. The polarizer array can apply 0° / 45° / 90° / 135° phase shifts to two orthogonally polarized circularly polarized beams, thereby achieving four-step phase shifting and finally imaging on the CMOS.

[0005] The specific measurement principle is as follows: The multi-wavelength synthetic dynamic interferometer collects data at the (X, Y) positions of the test sample. Interference phase measured at wavelength With being in Interference phase measured at wavelength Calculate the synthesized wavelength Synthetic phase Thus, the cophase error is obtained. Where (X, Y) is the sub-mirror coordinate system, Let be the camera target surface imaging coordinate system, and there is a one-to-one correspondence between the two.

[0006] Multi-wavelength synthetic dynamic interferometers suffer from error amplification, i.e., residual measurement wavelengths. and The actual residual calculation shows a synthesis wavelength on the nanometer scale. This can reach the μm or even mm level, expanding the measurement range but also amplifying the error by hundreds or thousands of times. Therefore, it is necessary to minimize the error between two measurements, mainly including: 1. The output wavelength and polarization state of the light source in the multi-wavelength synthesis dynamic interferometer drift randomly, and the wavelength change directly affects the wavelengths used in the calculation and synthesis. The value; however, due to the large number of polarization elements inside the interferometer, the change in polarization state makes the light intensity signal collected by the CCD too dark, affecting the recognition of the light intensity signal, which will degrade the measurement accuracy. 2. The polarization camera in a dynamic interferometer consists of a lens, a polarizer, and a CCD array, which inevitably introduces parasitic interference fringes, reducing measurement accuracy. 3. The multi-wavelength synthetic dynamic interferometer requires only one polarization camera to achieve phase shifting, avoiding the installation errors introduced by imaging with four CCD cameras and reducing installation difficulty. However, since the multi-wavelength synthetic dynamic interferometer can operate at wavelengths exceeding 50nm, it is still necessary to consider the radial deviation of the effective image area caused by chromatic aberration of the optical system and the centroid position deviation of the effective image area caused by environmental disturbances, which may affect the interference phase of the two CCD acquisitions. and No longer the same point on the test sample . Summary of the Invention

[0007] To address the aforementioned issues, this application provides a method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer.

[0008] This application provides a method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer, employing the following technical solution: A method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer includes the following steps: Step S1: Set up a detection and control module, and select two lasers in the detection and control module as the first laser and the second laser respectively, so that the fringe contrast of the interference light field of the first laser and the second laser is greater than the contrast threshold. Step S2: Acquire parasitic interferometric images and design band-stop filters based on the parasitic interferometric images. ; Step S3: Using the first laser as the light source, acquire images of the test sample. During image acquisition, the real-time wavelength information of the first laser is recorded; a second laser is used as the light source to acquire images of the test sample. And record the real-time wavelength information of the second laser during the image acquisition process; Step S4: Pass through the band-stop filter in step S2 Get and The for The interference image after removing parasitic interference fringes, the for Interference image after removing parasitic interference fringes; Step S5, Obtain The minimum circumcircle of the effective region and The minimum circumcircle of the effective region and with As a benchmark Make corrections and take the corrected version. and The intersection region is the final effective region M; Step S6: Perform unpacking calculation on the final effective region M.

[0009] Preferably, the detection and control module includes at least two lasers, an achromatic polarizing beam splitter, a beam splitter wedge, a fiber optic coupler, a wavelength meter, a host computer, and an aperture. The achromatic polarizing beam splitter and the beam splitting wedge are arranged sequentially along the optical path propagation direction. The multiple lasers are located at multiple incident ends of the achromatic polarizing beam splitter. A half-wave plate and an optical switch are arranged sequentially between any laser and the achromatic polarizing beam splitter along the laser emission direction. A first rotary motor for driving the rotation of any half-wave plate is provided, and a second rotary motor for driving the rotation of any optical switch is provided. The beam-splitting wedge is used to guide part of the laser power emitted by any laser to the wavelength meter. The remaining laser power emitted by any laser is received by the multi-wavelength synthesis dynamic interferometer. The signal output terminal of the wavelength meter is connected to the signal input terminal of the host computer. The multi-wavelength synthesis dynamic interferometer is controlled by the host computer. The aperture is located between the output end of the multi-wavelength synthetic dynamic interferometer and the test sample, and the aperture is connected to the signal output end of the host computer. The signal output terminal of the host computer is connected to the signal input terminals of any first rotary motor and any second rotary motor.

[0010] Preferably, step S1 includes the following steps: Step S11: Open the aperture; Step S12: Control the optical switch in front of the first laser to open via the host computer, while keeping the optical switch in front of the second laser closed, and read the contrast of the interference light field. ,Will With contrast threshold If compared, Less than , then the upper computer controls the first rotating motor to adjust the half-wave plate in front of the first laser, until greater than or equal to ; Step S13: Control the optical switch in front of the second laser to be turned on and the optical switch in front of the first laser to be turned off through the upper computer, and read the contrast of the interference light field , take the contrast threshold for comparison, if less than , then the upper computer controls the first rotating motor to adjust the half-wave plate in front of the second laser, until greater than or equal to .

[0011] Preferably, in the step S12 and the step S13, the contrast and are calculated from the pixel brightness, and the pixel brightness is obtained by analyzing a 256-order grayscale image.

[0012] Preferably, the step S2 includes the following steps: Step S21: Close the aperture, turn on the optical switch in front of the first laser, and turn off the optical switch in front of the second laser; Step S22: Collect the parasitic interference image ; Step S23: Design a band-stop filter , perform Fourier transform on to obtain spectrum information , according to the maximum amplitude in the spectrum , the spectral intensity corresponding to the parasitic interference image is obtained as , where v is the frequency; Step S24: Set a coefficient k (0<k<1), and mark the frequency v whose amplitude is greater than as the frequency corresponding to the parasitic interference image, which is suppressed by the band-stop filter in subsequent calculations.

[0013] Preferably, the step S3 includes the following steps: Step S31: Open the aperture; Step S32: Turn on the optical switch in front of the first laser, keep the optical switch in front of the second laser closed, and collect , during the image acquisition process, obtain the real-time wavelength information of the laser emitted by the first laser through the wavelength meter and record it to the upper computer; Step S33: Turn on the optical switch in front of the second laser, turn off the optical switch in front of the first laser, and collect , during the image acquisition process, obtain the real-time wavelength information of the laser emitted by the second laser through the wavelength meter and record it to the upper computer.

[0014] Preferably, step S4 includes the following steps: Step S41, for Perform Fourier transform to obtain ,right Perform Fourier transform to obtain ; Step S42: Pass through a band-stop filter Get and The for The filtered spectrum, the for Filtered spectrum; Step S43, for Perform inverse Fourier transform to obtain ,right Perform inverse Fourier transform to obtain .

[0015] Preferably, step S5 includes the following steps: Step S51, regarding the steps in S42 and Perform effective area division; Step S52, Confirm The minimum circumcircle of the effective region ,Sure The minimum circumcircle of the effective region ; Step S53, with As a benchmark Perform centroidal and radial corrections; Step S54: Take the corrected and The intersection region is the final effective region M.

[0016] Preferably, step S53 includes the following steps: Step S531, Obtain centroid ( ) and radius , obtain centroid ( ) and radius R2; Step S532, Calculation , as well as The The difference between x1 and x2 is used to represent... Compared to The x-axis position deviation; The difference between y1 and y2 is used to represent... Compared to The y-direction position deviation; R1 is the ratio of R2, used to represent... Compared to Radial deviation; Step S533: Correct x2, y2, and R2 so that =0、 =0 and =1, to obtain The For After centroidal and radial corrections based on the reference .

[0017] In summary, the method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer according to this application has at least the following beneficial technical effects: 1. By controlling the contrast of the interference field fringes of the interferometer light source, random errors introduced by the laser can be suppressed; 2. By setting a band-stop filter, parasitic interference introduced by the polarization camera can be corrected, systematic errors can be suppressed, and measurement accuracy can be further improved; 3. By correcting the radial deviation and centroid deviation of the effective area recognition range, random errors introduced by color difference and environment can be corrected. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating a method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer, as described in an embodiment of this application. Figure 2 This is a schematic diagram illustrating the positional relationship between a laser, a half-wave plate, an optical switch, an achromatic polarizing beam splitter, a fiber optic coupler, and a wavelength meter, according to an embodiment of this application.

[0019] Figure 3 This is a schematic diagram illustrating the installation position of the aperture in an embodiment of this application.

[0020] Figure 4 This is an example of an embodiment of the present application used to demonstrate the effect comparison before and after the removal of parasitic interference fringes.

[0021] Figure 5 This is a schematic diagram used in the embodiments of this application to illustrate the valid and invalid regions.

[0022] Figure 6 This is the smallest circumcircle used in the embodiments of this application to demonstrate the effective area. A schematic diagram.

[0023] Figure 7This embodiment of the application is used to demonstrate the minimum circumcircle. and A schematic diagram of the centroidal and radial deviations between them.

[0024] Figure 8 This embodiment of the application is used to demonstrate the surface measurement error when unpacking the final effective region M without centroidal deviation correction and radial deviation correction.

[0025] Figure 9 This embodiment of the application is used to demonstrate the surface measurement error when unpacking and calculating the final effective region M after centroid deviation correction.

[0026] Figure 10 This embodiment of the application is used to demonstrate the surface measurement error when unpacking and calculating the final effective region M after completing the centroid deviation correction and radial deviation correction.

[0027] Explanation of reference numerals in the attached figures: 1. Achromatic polarizing beam splitter; 2. Beam splitter wedge; 3. Fiber optic coupler; 4. Wavelength meter; 5. Host computer; 6. Aperture; 7. Multi-wavelength synthesizing dynamic interferometer; 8. Half-wave plate; 9. Optical switch; 10. First rotating motor; 11. Second rotating motor; 12. Test sample; 13. First laser; 14. Second laser. Detailed Implementation

[0028] The following combination Figures 1-10 This application will be described in further detail.

[0029] Example This application discloses a method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer, referring to... Figure 1 It mainly includes the following steps: Step S1: Set up a detection and control module, and select two lasers in the detection and control module as the first laser and the second laser respectively, so that the fringe contrast of the interference light field of the first laser and the second laser is greater than the contrast threshold. Step S2: Acquire parasitic interferometric images and design band-stop filters based on the parasitic interferometric images. ; Step S3: Using the first laser as the light source, acquire images of the test sample. During image acquisition, the real-time wavelength information of the first laser is recorded; a second laser is used as the light source to acquire images of the test sample. And record the real-time wavelength information of the second laser during the image acquisition process; Step S4: Pass through the band-stop filter in step S2 Get and The for The interference image after removing parasitic interference fringes, the for Interference image after removing parasitic interference fringes; Step S5, Obtain The minimum circumcircle of the effective region and The minimum circumcircle of the effective region and with As a benchmark Make corrections and take the corrected version. and The intersection region is the final effective region M; Step S6: Perform unpacking calculation on the final effective region M.

[0030] It should be noted that the unpacking algorithm uses conventional existing techniques, such as branch cutting, quality graph, Monte Carlo algorithm, etc., which will not be restricted or elaborated here.

[0031] The detection and control module includes at least two lasers, an achromatic polarizing beam splitter 1, a beam splitter wedge 2, a fiber optic coupler 3, a wavelength meter 4, a host computer 5, and an aperture 6. This module enables self-testing before polarization state measurement and real-time wavelength monitoring.

[0032] Reference Figure 2 Two lasers are located at the two incident ends of the achromatic polarizing beam splitter 1, and a half-wave plate 8 and an optical switch 9 are sequentially arranged at the emitting end of each laser along the laser propagation direction. A first rotary motor 10 is provided for driving the rotation of each half-wave plate 8, and a second rotary motor 11 is provided for driving the rotation of each optical switch 9.

[0033] It should be noted that in this embodiment, the optical switch 9 can be an optical fiber 1*N optical switch, a mechanical optical switch, or an acousto-optic modulator, etc., which will not be limited or elaborated here.

[0034] Achromatic polarizing beam splitter 1 and beam splitting wedge 2 are arranged sequentially along the optical path propagation direction. Beam splitting wedge 2 is used to guide part of the power of the laser emitted by any laser (4% power in this embodiment) to wavelength meter 4, while the remaining power of the laser is received by multi-wavelength synthesizing dynamic interferometer 7.

[0035] Reference Figure 3 The aperture 6 is positioned between the output end of the multi-wavelength synthesized dynamic interferometer 7 and the test sample 12. The aperture 6 is connected to the signal output end of the host computer 5 to control the on / off state of the optical path.

[0036] The signal input terminal of the host computer 5 is connected to the signal output terminal of the wavelength meter 4. The signal output terminal of the host computer 5 is also connected to the signal input terminals of the two first rotary motors 10 and the two second rotary motors 11. The multi-wavelength synthesizing dynamic interferometer 7 is controlled by the host computer 5. The host computer 5 can control the aperture 6 to block or avoid the optical path, control the two first rotary motors 10 to drive the half-wave plate 8 to rotate, and control the two second rotary motors 11 to drive the optical switch 9 to rotate.

[0037] During image acquisition, wavelength meter 4 can acquire the real-time wavelength information of the first laser 13 and the second laser 14 and transmit it to the interferometer measurement software of the host computer 5 in real time, so that the interference image is matched with the output wavelength at the acquisition time in real time, thereby reducing the random error of the light source of the multi-wavelength synthesis dynamic interferometer 7 and improving the measurement accuracy.

[0038] Step S1 includes the following steps: Step S11: Open the aperture; Step S12: Control the optical switch in front of the first laser to open via the host computer, while keeping the optical switch in front of the second laser closed, and read the contrast of the interference light field. ,Will With contrast threshold If compared, Less than Then, the host computer controls the first rotary motor to adjust the half-wave plate in front of the first laser until... Greater than or equal to ; Step S13: Control the optical switch in front of the second laser to open and the optical switch in front of the first laser to close via the host computer, and read the contrast of the interference light field. ,Will Contrast threshold If compared, Less than Then, the host computer controls the first rotary motor to adjust the half-wave plate in front of the second laser until... Greater than or equal to .

[0039] In steps S12 and S13, the contrast... and The pixel brightness is calculated based on the analysis of a 256-level grayscale image. and The calculation formula is: ; .

[0040] In the formula, is the maximum value of pixel brightness in the interference image collected when the first laser is used as the light source; is the minimum value of pixel brightness in the interference image collected when the first laser is used as the light source; is the maximum value of pixel brightness in the interference image collected when the second laser is used as the light source; is the minimum value of pixel brightness in the interference image collected when the second laser is used as the light source.

[0041] In this embodiment, the contrast threshold is set to 0.9. If (or ) ≥ 0.9, it is determined that the fringe contrast of the interference light field of the first laser (or the second laser) is qualified; if (or ) < 0.9, it is determined that the fringe contrast of the interference light field of the first laser (or the second laser) is unqualified. In some other embodiments, the value of may also be adjusted according to the requirements of measurement accuracy, which is not limited or elaborated herein.

[0042] By controlling the fringe contrast of the interference light field of the interferometer light source, random errors introduced by the laser can be suppressed.

[0043] Step S2 includes the following steps: Step S21: Close the aperture, turn on the optical switch in front of the first laser, and turn off the optical switch in front of the second laser; Step S22: Collect the parasitic interference image ; Step S23: Design a band-stop filter , perform Fourier transform on to obtain spectral information , and obtain that the spectral intensity corresponding to the parasitic interference image is according to the maximum amplitude in the spectrum, where v is the frequency; Step S24: Set a coefficient k (0 < k < 1), mark the frequency v with an amplitude greater than as the frequency corresponding to the parasitic interference image, which is suppressed by the band-stop filter in subsequent calculations.

[0044] wherein, the expression of the band-stop filter is: .

[0045] In this embodiment, the value of k is 0.1. It should be noted that for different polarization cameras, due to variations in their manufacturing processes, the severity of parasitic interference images varies. The minimum coefficient k that can filter out the parasitic interference image can be determined during testing based on the actual situation. For example, the coefficient k can be gradually decreased until the parasitic interference fringes can no longer be filtered out.

[0046] Furthermore, since different laser wavelengths do not affect the interference frequency, the interference image acquired using the first laser as the light source is used as the basis for the calculation. The designed band-stop filter can be applied to lasers of different wavelengths.

[0047] Step S3 includes the following steps: Step S31: Open the aperture; Step S32: Turn on the optical switch in front of the first laser, keep the optical switch in front of the second laser closed, and collect data. During the image acquisition process, the real-time wavelength information of the laser emitted by the first laser is obtained by a wavelength meter and recorded to the host computer; Step S33: Turn on the optical switch in front of the second laser, turn off the optical switch in front of the first laser, and collect data. During the image acquisition process, the real-time wavelength information of the laser emitted by the second laser is obtained by a wavelength meter and recorded to the host computer.

[0048] Step S4 includes the following steps: Step S41, for Perform Fourier transform to obtain ,right Perform Fourier transform to obtain ; Step S42: Pass through a band-stop filter Get and The for The filtered spectrum, the for Filtered spectrum; Step S43, for Perform inverse Fourier transform to obtain ,right Perform inverse Fourier transform to obtain .

[0049] in, ; ; ; .

[0050] In the formula, for Frequency domain image; for Frequency domain image; This is the inverse Fourier transform.

[0051] like Figure 4 As shown, taking a single circular lens as an example, Figure 4 (a) is the original image acquired using the first laser as the light source. The image contains superimposed parasitic interference fringes. Image (b) is a parasitic interference image. Image (c) is the image after parasitic interference has been eliminated. Through a band-stop filter The settings can correct parasitic interference introduced by the polarization camera, suppress systematic errors, and further improve measurement accuracy.

[0052] Step S5 includes the following steps: Step S51, regarding the steps in S42 and Perform effective area division; Step S52, Confirm The minimum circumcircle of the effective region ,Sure The minimum circumcircle of the effective region ; Step S53, with As a benchmark Perform centroidal and radial corrections; Step S54: Take the corrected and The intersection region is the final effective region M.

[0053] Step S53 includes the following steps: Step S531, Obtain centroid ( ) and radius , obtain centroid ( ) and radius R2; Step S532, Calculation , as well as The The difference between x1 and x2 is used to represent... Compared to The x-axis position deviation; The difference between y1 and y2 is used to represent... Compared to The y-direction position deviation; R1 is the ratio of R2, used to represent... Compared to Radial deviation; Step S533: Correct x2, y2, and R2 so that =0、 =0 and =1, to obtain The For After centroidal and radial corrections based on the reference .

[0054] It should be noted that in this embodiment, in step S51, and The effective region division is achieved through modulation segmentation algorithm; in step S52, after identifying the number of connected components using the four-neighbor method, the optimal solution is obtained. and These are all existing technologies and will not be elaborated upon here.

[0055] The core error of the multi-wavelength synthesis algorithm lies in the fact that the pixel coordinates of the effective regions of the images of the sample acquired twice, using the first and second lasers as light sources, cannot correspond to the coordinates of the same pixel on the sample. This error is caused by... By correcting the centroid and radial direction, it can be made and Each pixel corresponds to the same position on the sample being tested.

[0056] For example, consider a test sample consisting of three centrally symmetrical splicing mirror groups. Interference images of the sample are acquired using the first laser as the light source. ,right After performing parasitic interference removal treatment, in The effective area range identified in the middle is as follows Figure 5 As shown, the white areas are valid regions, and the black areas are invalid regions. Figure 6 As shown, the effective regions are connected components #1, #2, and #3. The minimum circumcircle of the three connected components is... , The centroid is ( ), with a radius of R1.

[0057] Sample interference images were acquired using a second laser as the light source. ,right After performing parasitic interference removal treatment, in The smallest circumcircle of the identified effective region is , The centroid is ( ), radius is .

[0058] Depend on Figure 7 As shown, and There are centroidal deviations caused by random errors introduced by the environment and radial deviations caused by color differences. These are corrected... and The centroidal deviation and radial error can correct for random errors and color differences introduced by the environment.

[0059] Taking a circular lens as an example, the first laser used is a 633nm laser. The smallest circumcircle of the effective region identified in the middle centroid ( (128, 128) with radius The value is 99; the second laser is a 650nm laser. The smallest circumcircle of the effective region identified in the middle centroid ( (129, 129) with radius It is 94.

[0060] After testing, and x-axis position deviation =1, y-axis position deviation =1, Radial deviation =0.95; take directly and When the intersection region is used as the final valid region for unpacking calculation, color difference and random errors introduced by the environment coexist, such as... Figure 8 As shown, the surface shape measurement error reaches 4000 nm; when... Correct the centroid position so that =0、 When = 0, the random errors introduced by the environment have been corrected, such as Figure 9 As shown, the surface shape measurement error reaches 400 nm; when... Further color difference correction was performed to make =0、 =0, and Increase by 1.05 times (at this time) When it approaches 1), both color difference and random errors introduced by the environment have been corrected, such as... Figure 10 The final surface shape measurement error is within 10. -12 The error is on the order of nm and can be ignored.

[0061] It is evident that by correcting the radial deviation and centroid deviation of the effective area recognition range, random errors introduced by color difference and environment can be corrected.

[0062] The implementation principle of the method for correcting measurement errors of a multi-wavelength synthetic dynamic interferometer in this application embodiment is as follows: by combining the adjustment of the contrast of the interference light field fringes, the correction of parasitic interference, and the correction of the radial deviation and centroid deviation of the effective area identification range, the error amplification effect of multi-wavelength interferometric measurement can be effectively suppressed, the measurement accuracy can be improved, and the compatibility of the multi-wavelength synthetic dynamic interferometer can be improved.

[0063] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer, characterized in that, Includes the following steps: Step S1: Set up a detection and control module, and select two lasers in the detection and control module as the first laser and the second laser respectively, so that the fringe contrast of the interference light field of the first laser and the second laser is greater than the contrast threshold. Step S2: Acquire parasitic interferometric images and design band-stop filters based on the parasitic interferometric images. ; Step S3: Using the first laser as the light source, acquire images of the test sample. And record the real-time wavelength information of the first laser during the image acquisition process; A second laser was used as the light source to acquire images of the test sample. And record the real-time wavelength information of the second laser during the image acquisition process; Step S4: Pass through the band-stop filter in step S2 Get and The for The interference image after removing parasitic interference fringes, the for Interference image after removing parasitic interference fringes; Step S5, Obtain The minimum circumcircle of the effective region and The minimum circumcircle of the effective region and with As a benchmark Make corrections and take the corrected version. and The intersection region is the final effective region M; Step S6: Perform unpacking calculation on the final effective region M.

2. The method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer according to claim 1, characterized in that, The detection and control module includes at least two lasers, an achromatic polarizing beam splitter, a beam splitter wedge, a fiber optic coupler, a wavelength meter, a host computer, and an aperture. The achromatic polarizing beam splitter and the beam splitting wedge are arranged sequentially along the optical path propagation direction. The multiple lasers are located at multiple incident ends of the achromatic polarizing beam splitter. A half-wave plate and an optical switch are arranged sequentially between any laser and the achromatic polarizing beam splitter along the laser emission direction. A first rotary motor for driving the rotation of any half-wave plate is provided, and a second rotary motor for driving the rotation of any optical switch is provided. The beam-splitting wedge is used to guide part of the laser power emitted by any laser to the wavelength meter. The remaining laser power emitted by any laser is received by the multi-wavelength synthesis dynamic interferometer. The signal output terminal of the wavelength meter is connected to the signal input terminal of the host computer. The multi-wavelength synthesis dynamic interferometer is controlled by the host computer. The aperture is located between the output end of the multi-wavelength synthetic dynamic interferometer and the test sample, and the aperture is connected to the signal output end of the host computer. The signal output terminal of the host computer is connected to the signal input terminals of any first rotary motor and any second rotary motor.

3. The method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer according to claim 2, characterized in that, Step S1 includes the following steps: Step S11: Open the aperture; Step S12: Control the optical switch in front of the first laser to open via the host computer, while keeping the optical switch in front of the second laser closed, and read the contrast of the interference light field. ,Will With contrast threshold If compared, Less than Then, the host computer controls the first rotary motor to adjust the half-wave plate in front of the first laser until... Greater than or equal to ; Step S13: Control the optical switch in front of the second laser to open and the optical switch in front of the first laser to close via the host computer, and read the contrast of the interference light field. ,Will Contrast threshold If compared, Less than Then, the host computer controls the first rotary motor to adjust the half-wave plate in front of the second laser until... Greater than or equal to .

4. The method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer according to claim 3, characterized in that, In steps S12 and S13, the contrast... and The pixel brightness is calculated based on the analysis of a 256-level grayscale image.

5. The method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer according to claim 2, characterized in that, Step S2 includes the following steps: Step S21: Close the aperture, turn on the optical switch in front of the first laser, and turn off the optical switch in front of the second laser; Step S22: Acquire parasitic interferometry images ; Step S23: Design a band-stop filter ,right Perform Fourier transform to obtain spectral information According to the spectrum The spectral intensity corresponding to the largest magnitude of the parasitic interferometric image is , where v is the frequency; Step S24: Set a coefficient k (0<k<1), and a frequency with an amplitude greater than v is designated as the frequency corresponding to the parasitic interference image, which is suppressed by a band-stop filter in subsequent calculations.

6. The method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer according to claim 5, characterized in that, Step S3 includes the following steps: Step S31: Open the aperture; Step S32: Turn on the optical switch in front of the first laser, keep the optical switch in front of the second laser closed, and collect data. During the image acquisition process, the real-time wavelength information of the laser emitted by the first laser is obtained by a wavelength meter and recorded to the host computer; Step S33: Turn on the optical switch in front of the second laser, turn off the optical switch in front of the first laser, and collect data. During the image acquisition process, the real-time wavelength information of the laser emitted by the second laser is obtained by a wavelength meter and recorded to the host computer.

7. The method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer according to claim 6, characterized in that, Step S4 includes the following steps: Step S41, for Perform Fourier transform to obtain ,right Perform Fourier transform to obtain ; Step S42: Pass through a band-stop filter Get and The for The filtered spectrum, the for Filtered spectrum; Step S43, for Perform inverse Fourier transform to obtain ,right Perform inverse Fourier transform to obtain .

8. The method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer according to claim 7, characterized in that, Step S5 includes the following steps: Step S51, regarding the steps in S42 and Perform effective area division; Step S52, Confirm The minimum circumcircle of the effective region ,Sure The minimum circumcircle of the effective region ; Step S53, with As a benchmark Perform centroidal and radial corrections; Step S54: Take the corrected and The intersection region is the final effective region M.

9. A method for correcting measurement errors in a multi-wavelength synthetic dynamic interferometer according to claim 8, characterized in that, Step S53 includes the following steps: Step S531, Obtain centroid ( ) and radius , obtain centroid ( ) and radius R2; Step S532, Calculation , as well as The The difference between x1 and x2 is used to represent... Compared to The x-axis position deviation; The difference between y1 and y2 is used to represent... Compared to The y-direction position deviation; R1 is the ratio of R2, used to represent... Compared to Radial deviation; Step S533: Correct x2, y2, and R2 so that =0、 =0 and =1, to obtain The For After centroidal and radial corrections based on the reference .

Images