High-precision anti-vibration large-aperture mechanical phase-shifting interferometry method and device

Abstract

The invention discloses a high-precision anti-vibration large-aperture mechanical phase-shifting interference measurement method and device, and belongs to the technical field of optical precision measurement. The implementation method comprises the following steps: acquiring a phase shift initial value through a principal component analysis method; calculating background light intensity and modulation degree parameters of the interferogram to obtain an initial value of an iterative algorithm; by establishing an environment vibration error model, the capability of suppressing noise such as measured environment vibration and the like is improved; the iterative linear regression algorithm is combined with the initial estimation of the measured surface shape, and the space and time variables are iteratively solved respectively, so that the response speed and the measurement precision of the system are improved. The method has the advantages of being high in convergence speed and robustness, the initial value of the measured surface shape, the modulation degree and background noise are obtained, the noise model changing along with time is constructed, suppression of environment noise is achieved, and high-precision measurement of the surface shape parameters of the large-aperture optical element is achieved.

Description

Technical Field

[0001] The invention relates to a high-precision vibration-resistant large-aperture mechanical phase-shifting interference measurement method and device, belonging to the technical field of optical precision measurement. Background Art

[0002] Phase-shift interferometry is widely used in astronomical telescopes, inertial confinement fusion devices, semiconductor wafer inspection and other high-precision optical systems as an extremely important detection method for high-precision optical components due to its unique high-precision measurement capabilities and background interference elimination capabilities in the field of interferometry. Phase-shift interferometry algorithm is one of the most important components of PSI. Under the same hardware and environmental conditions, the performance of the algorithm directly determines the measurement accuracy. Both the traditional fixed-step algorithm and the classic random phase-shift interferometry algorithm assume that the phase-shift error is uniform in the pupil plane, that is, there is only a "position phase-shift error". However, in actual measurements, various factors such as environmental vibration will inevitably cause the phase-shift plane to tilt, thereby introducing a "tilt phase-shift error". Therefore, neither the fixed-step phase-shift algorithm nor the random phase-shift algorithm can eliminate the influence of the tilt phase-shift error on the measurement accuracy, which leads to the need to further improve the measurement accuracy of the current phase-shift interferometry detection, and expensive precision phase shifters are still required to ensure the measurement accuracy.

[0003] In fact, improving the anti-vibration phase-shift error performance of the phase-shift interferometer algorithm has become the key to further improve the accuracy of phase-shift interferometer measurement and completely get rid of expensive high-precision phase shifters. To this end, a variety of anti-tilt phase-shift interferometer algorithms have been proposed, and they can be divided into two categories according to whether an iterative process is required. One type is a non-iterative algorithm with a faster calculation speed, but generally low accuracy. For example, Oleg Soloviev et al. and Li et al. proposed to use the zero-crossing point generated by the subtraction of the phase-shift interferogram to solve the tilt phase-shift parameters and then extract the phase distribution. However, this method requires a large tilt phase-shift error to significantly change the direction of the stripes, otherwise it cannot be calculated, and therefore cannot handle small tilt errors. MACIEK WIELGUS et al. proposed an algorithm that can handle two frames of both large and small tilt phase errors, but the nonlinear minimization method it uses makes the algorithm more complicated. Liu et al. divided the tilt amplitude into three cases according to size, and used the corresponding algorithms for calculation respectively. This method has the ability to handle a large range of tilt phase errors, but its classification judgment and classification processing process makes it difficult to automatically cope with various situations that may occur in actual measurements.

[0004] On the other hand, the iterative algorithm has high calculation accuracy, but slow calculation speed. Chen et al. and L.Deck converted the transcendental equation containing the tilt phase shift coefficient into a linear form through a first-order Taylor expansion, and then calculated the phase distribution through a linear least squares iteration method. Liu et al. proposed a three-step iterative method, which iteratively calculates the tilt phase shift coefficients in two directions respectively, and finally extracts the phase distribution. The above algorithm has high requirements on the accuracy of the initial value of the iteration. If the phase shift error is too large, the accuracy and speed of the algorithm will be significantly reduced, and it may even fail to converge to the correct result. In summary, it is difficult for existing methods to meet the requirements of high precision at the same time, and it is generally difficult to handle a large range of phase shift tilt phase shift errors. Summary of the invention

[0005] In view of the fact that existing methods are difficult to meet the requirements of high precision and high speed at the same time, and are not robust enough to handle large-scale phase shift, tilt and phase shift errors, the purpose of the present invention is to provide a high-precision, vibration-resistant, large-aperture mechanical phase-shifting interferometric measurement method and device, which obtains initial measured surface parameters through a principal component analysis method; obtains initial values ​​of phase shift amounts based on the initial measured surface parameters; obtains initial values ​​of an iterative algorithm by calculating background light intensity and modulation of an interference pattern, and improves the surface accuracy of the measured surface based on the initial values; improves the ability to suppress vibration noise in the measured environment by establishing an environmental vibration error model; combines an initial estimate of the measured surface shape through an iterative linear regression algorithm, and iteratively solves spatial and temporal variables respectively, which has the characteristics of fast convergence speed and strong robustness, effectively suppresses environmental vibrations, and improves the response speed and measurement accuracy of the device.

[0006] The purpose of the present invention is achieved through the following technical solutions.

[0007] The present invention discloses a high-precision vibration-resistant large-aperture mechanical phase-shifting interferometry measurement method and device, comprising the following steps:

[0008] Step 1: Collect the interference fringe pattern of the measured surface through a large-aperture interferometer, obtain the phase distribution of the measured surface through principal component analysis, and calculate the true initial value of the phase shift;

[0009] The outgoing light beam of the interferometer host is reflected by the reference mirror TF and the standard mirror RF in turn to form reference light and measurement light. The reference light and measurement light return along the optical axis of the interferometer system. When the reference light and measurement light interfere with each other, interference fringes are formed. The light intensity of the interference pattern with environmental vibration noise is expressed as:

[0010]

[0011] Among them, A(x,y) represents the background light intensity of the interference fringes; V(x,y) represents the modulation degree of the interference fringes; It is represented by the wavefront phase distribution of the measurement light reflected by RF; δ(x, y, t) represents the phase shift amount. Environmental vibration causes the phase shift plane to tilt, which is expressed as:

[0012] δ(x,y,t)=α n x+β n y+γ n (1)

[0013] where α n , β n and γ n They represent the tilt phase shift coefficient and translation phase shift in the x and y directions caused by environmental vibration respectively; the phase distribution is quickly calculated by the principal component analysis algorithm

[0014] The background light intensity and modulation degree in formula (1) do not change with the pixel, that is, A m (x,y)=a m ,B m (x,y)=b m , where a m and b m are two constants independent of pixels, expressed as:

[0015]

[0016] Among them C m (t 0 )=b m cosδ m (t 0 ), S m (t 0 )=-b m sinδ m (t 0 ); Since formula (3) is m and S m is linear, and S is obtained by linear least squares method m (t 0 ) and C m (t 0 ), then the actual initial value of the phase shifter δ(t 0 ) is obtained by the inverse tangent formula:

[0017]

[0018] The phase shift obtained by formula (4) is wrapped in the range of (-π, π]; the unwrapping criterion SD = δ m (n)-δ m (n-1), when |SD|<π, it is considered that δ(t 0 ) is not wrapped;

[0019] Step 2: Obtain the real background light intensity and modulation through the interference pattern obtained in step 1;

[0020] According to the obtained interference pattern, the background light intensity A(x, y) and modulation V(x, y) in the interference pattern are extracted and expressed as:

[0021]

[0022] Where I(x,y,t) is the light intensity value of the interference pattern obtained by interfering the measured surface.

[0023] Step 3: Suppress noise by establishing an error model of environmental vibration noise;

[0024] Due to environmental vibration, the measurement cavity formed by the measured mirror and the reference mirror changes in real time; the noise model expression of the cavity structure is established:

[0025]

[0026] Among them, τ(t) is the phase shift over time; α(t) and β(t) are the tilt coefficients of the reference surface and the measured surface, and ρ(x) 2 =x 2 +y 2 , c is the phase curvature. When the measured surface is a plane, c = 0; t 0 represents the time when the first interference pattern is collected. Then the new estimated value is expressed as:

[0027] δ n (t) = δ(t) + δ'(t)

[0028] α n (t)=α(t)+α'(t) (7)

[0029] β n (t) = β(t) + β'(t)

[0030] Where subscript δ n (t), α n (t), β n (t) represents the new estimated value; δ'(t), α'(t), β'(t) represent the deviation values;

[0031] Substituting equation (7) into equation (1), we can obtain the actual light intensity expression affected by the environment:

[0032]

[0033] in,

[0034]

[0035] K represents the iteration level, k represents the number of iterations, k = 1, 2, ... K; g represents the square root of the product of the reflectivity of the measured mirror and the reference mirror, which characterizes the reflection quality of the cavity. This value is greatly affected by the environment and is updated according to the increase in the number of iterations; the iterative evaluation function is expressed as:

[0036]

[0037] Wherein, M represents the number of phase shifts; noise suppression is achieved by updating the time-related variables δ(t), α(t), β(t) and iterative calculation.

[0038] Step 4: Based on the background light intensity and modulation degree obtained in step 2 and the cavity noise model established in step 3, an iterative linear regression algorithm is used to iteratively fit the phase shift plane and extract the phase to be measured.

[0039] The background light intensity A(x, y), modulation V(x, y) obtained in step 2 and δ(x, t) obtained in step 3 are introduced into the iterative linear regression algorithm and expressed as:

[0040]

[0041] in,

[0042]

[0043] During the phase-shift interferometry measurement, the corresponding interference pattern is obtained according to the phase-shift times M, and the iterative parameter g is updated and optimized:

[0044]

[0045] Whether to continue iterative calculation is determined by whether the iterative evaluation function χ(t) is lower than 0.1%. If the threshold condition is not met, it is brought into step 3 and step 4 for further iterative update calculation, and the g value is continuously updated until it converges to the evaluation function threshold; thus, the wrapped phase of the measured surface shape is obtained.

[0046] The present invention discloses a high-precision, vibration-resistant, large-aperture mechanical phase-shifting interferometer measurement device, which is realized based on the large-aperture, high-precision, phase-shifting interferometer, vibration-resistant measurement method. The large-aperture, high-precision, phase-shifting interferometer, vibration-resistant measurement device includes a laser, a beam splitter, a small-aperture collimator, a beam expander, a large-aperture collimator, a precision adjustment frame for a reference mirror, a reference mirror, a standard measured mirror, a precision adjustment frame for the standard measured mirror, a beam splitter prism, an imaging lens group, and a CCD camera; the point light source emitted by the point light source passes through the beam splitter and then passes through the small-aperture collimator to obtain parallel light of a preset aperture, passes through the beam expander group and the large-aperture collimator to obtain parallel light of a preset enlarged aperture, and one of the light beams is reflected by the rear surface of the reference mirror and then passes through the large-aperture collimator again. The reference light is formed after passing through the reference mirror, the beam expander, the small-aperture collimator and the beam splitter, and then reflected by the beam splitter prism; the other beam of light passes through the reference mirror, is reflected by the front surface of the measured mirror, and then passes through the reference mirror, the large-aperture collimator, the beam expander, the small-aperture collimator and the beam splitter again, and then reflected by the beam splitter prism to form the measuring light; when the reference light and the measuring light are coherently interfered, the interference pattern of the measured surface is collected by the interferometer; the high-precision phase solution is obtained according to the large-aperture high-precision phase-shifting interferometry anti-vibration measurement method, and the high-precision surface fitting is realized.

[0047] Preferably, the point light source emitted by the point light source passes through a beam splitter and then a small-aperture collimator to obtain parallel light with a diameter of 100 mm, and passes through a beam expander group and a large-aperture collimator to obtain parallel light with a diameter of 820 mm.

[0048] Beneficial effects:

[0049] 1. The present invention discloses a high-precision vibration-resistant large-aperture mechanical phase-shifting interferometry measurement method and device, which obtains the initial phase distribution of the measured surface shape through principal component analysis technology; according to the optical interference theory, the initial value of the phase shift amount is extracted, which is helpful for high-precision solution of the interferometer surface shape.

[0050] 2. The present invention discloses a high-precision vibration-resistant large-aperture mechanical phase-shifting interferometry measurement method and device, which calculates the wrapped phase value from the noise fringes through an iterative algorithm, ensuring that the interferometer can be used in conditions with large environmental interference, and calculates the true phase and true surface shape of the measured mirror, thereby realizing high-precision interferometry measurement of the interferometer, suppressing the interference of environmental noise, and improving the surface shape measurement accuracy in harsh environments.

[0051] 3. The present invention discloses a high-precision, vibration-resistant, large-aperture mechanical phase-shifting interferometry measurement method and device, which has low environmental requirements, can achieve high-precision surface parameter measurement of large-aperture optical components, and has the advantages of fast iteration speed and high measurement accuracy through accurate acquisition of initial values. It avoids the interference problem of existing interferometer measurements that are limited by environmental factors. The present invention can not only be used in large-aperture interferometer measurement systems, but is also applicable to small-aperture interferometers; the present invention provides a new method and means for large-aperture interferometers to achieve high-precision, interference-resistant interferometry measurements. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a flow chart of a high-precision, vibration-resistant, large-aperture mechanical phase-shifting interferometry measurement method of the present invention.

[0053] Figure 2 This is a high-precision vibration-resistant large-aperture mechanical phase-shifting interferometry measurement method and device diagram of the present invention;

[0054] Among them: 1-laser, 2-beam splitter, 3-small-aperture collimator, 4-beam expander, 5-large-aperture collimator, 6-precision adjustment frame of reference mirror, 7-reference mirror TF, 8-standard measured mirror RF, 9-precision adjustment frame of standard measured mirror, 10-beam splitter prism, 11-imaging lens group, 12-CCD camera, 13-interference fringe pattern, 14-wrapped phase diagram.

[0055] Figure 3 Result diagram of a high-precision, vibration-resistant, large-aperture mechanical phase-shifting interferometry measurement method according to the present invention. DETAILED DESCRIPTION

[0056] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0057] Example

[0058] like Figure 2 As shown, a high-precision, vibration-resistant, large-aperture mechanical phase-shifting interferometry measuring device disclosed in this embodiment includes a laser 1, a beam splitter 2, a small-aperture collimator 3, a beam expander 4, a large-aperture collimator 5, a precision adjustment frame 6 of a reference mirror, a reference mirror TF7, a standard measured mirror 8, a precision adjustment frame 9 of a standard measured mirror, a beam splitter prism 10, an imaging lens group 11, and a CCD camera 12. The outgoing light beam of the laser light source 1 passes through the beam splitter 2, is collimated into a parallel light beam by the collimator 3, and is successively reflected by the surfaces of the reference mirror 7 and the standard measured mirror 8 to form a reference light and a measuring light. The reference light and the measuring light return along the original path of the optical axis of the interferometer system. After the reference light and the measuring light are coherently interfered, they pass through the beam splitter 10 and are imaged by the imaging lens group 11 in the CCD camera 12. The formed interference fringes 13 are calculated by a large-aperture, high-precision, phase-shifting interferometry vibration-resistant measurement method to obtain a true phase diagram of the measured surface.

[0059] like Figure 1 As shown, this embodiment discloses a high-precision vibration-resistant large-aperture mechanical phase-shifting interferometry measurement method, and the specific implementation steps are as follows:

[0060] Step 1: Collect the interference fringe pattern of the measured surface through a large-aperture interferometer, obtain the phase distribution of the measured surface through principal component analysis, and calculate the true initial value of the phase shift;

[0061] The outgoing light beam of the interferometer host is reflected by the reference mirror TF and the standard mirror RF in turn to form reference light and measurement light. The reference light and measurement light return along the optical axis of the interferometer system. When the reference light and measurement light interfere with each other, interference fringes are formed. The light intensity of the interference pattern with environmental vibration noise is expressed as:

[0062]

[0063] Among them, A(x,y) represents the background light intensity of the interference fringes; V(x,y) represents the modulation degree of the interference fringes; It is represented by the wavefront phase distribution of the measurement light reflected by RF; δ(x, y, t) represents the phase shift amount. Environmental vibration causes the phase shift plane to tilt, which is expressed as:

[0064] δ(x,y,t)=α n x+β n y+γ n (2)

[0065] where α n , β n and γ n They represent the tilt phase shift coefficient and translation phase shift in the x and y directions caused by environmental vibration respectively; the phase distribution is quickly calculated by the principal component analysis algorithm

[0066] The background light intensity and modulation degree in formula (1) do not change with the pixel, that is, A m (x,y)=a m ,B m (x,y)=b m , where a m and b m are two constants independent of pixels, expressed as:

[0067]

[0068] Among them C m (t 0 )=b m cosδ m (t 0 ), S m (t0 )=-b m sinδ m (t 0 ); Since formula (3) is m and S m is linear, and S can be obtained by linear least squares method. m (t 0 ) and C m (t 0 ), then the actual initial value of the phase shifter δ(t 0 ) is obtained by the inverse tangent formula:

[0069]

[0070] The phase shift obtained by formula (4) is wrapped in the range of (-π, π]; the unwrapping criterion SD = δ m (n)-δ m (n-1), when |SD|<π, it is considered that δ(t 0 ) is not wrapped;

[0071] Step 2: Obtain the real background light intensity and modulation through the interference pattern obtained in step 1;

[0072] According to the obtained interference pattern, the background light intensity A(x, y) and modulation V(x, y) in the interference pattern are extracted and expressed as:

[0073]

[0074] Where I(x,y,t) is the light intensity value of the interference pattern obtained by interfering the measured surface.

[0075] Step 3: Suppress noise by establishing an error model of environmental vibration noise;

[0076] Due to environmental vibration, the measurement cavity formed by the measured mirror and the reference mirror changes in real time; the noise model expression of the cavity structure is established:

[0077]

[0078] Among them, τ(t) is the phase shift over time; α(t) and β(t) are the tilt coefficients of the reference surface and the measured surface, and ρ(x) 2 =x 2 +y 2 , c is the phase curvature. When the measured surface is a plane, c = 0; t 0 represents the time when the first interference pattern is collected. Then the new estimated value is expressed as:

[0079] δ n (t) = δ(t) + δ'(t)

[0080] α n (t)=α(t)+α'(t) (7)

[0081] β n (t) = β(t) + β'(t)

[0082] Where subscript δ n (t), α n (t), β n (t) represents the new estimated value; δ'(t), α'(t), β'(t) represent the deviation values;

[0083] Substituting equation (7) into equation (1), we can obtain the actual light intensity expression affected by the environment:

[0084]

[0085] in,

[0086]

[0087] K represents the iteration level. After calculation, it is found that K = 3 can meet the requirements. k represents the number of iterations, k = 1, 2, ... K. g represents the square root of the product of the reflectivity of the measured mirror and the reference mirror, which represents the reflection quality of the cavity. This value is greatly affected by the environment and is updated according to the increase in the number of iterations. The iterative evaluation function is expressed as:

[0088]

[0089] Wherein, M represents the number of phase shifts; noise suppression is achieved by updating the time-related variables δ(t), α(t), β(t) and iterative calculation.

[0090] Step 4: Based on the background light intensity and modulation degree obtained in step 2 and the cavity noise model established in step 3, an iterative linear regression algorithm is used to iteratively fit the phase shift plane and extract the phase to be measured.

[0091] The background light intensity A(x, y), modulation V(x, y) obtained in step 2 and δ(x, t) obtained in step 3 are introduced into the iterative linear regression algorithm and expressed as:

[0092]

[0093] in,

[0094]

[0095] During the phase-shift interferometry measurement, the corresponding interference pattern is obtained according to the phase-shift times M, and the iterative parameter g is updated and optimized:

[0096]

[0097] When the iterative evaluation function χ(t) = 0.1%, the iterative calculation is stopped. When the threshold condition is not met, it is brought into step 3 and step 4 for further iterative update calculation, and the g value is continuously updated until it converges to the evaluation function threshold; then the wrapped phase of the measured surface shape is obtained. When the ripple error caused by environmental vibration is greater than 30nm, the traditional phase shift method cannot be used to solve it. By using the present invention, the measured surface shape can be solved and the influence of environmental noise can be effectively suppressed. Figure 3 As shown, the measured surface shape PV is 0.09λ.

[0098] The specific implementation modes of the present invention are described above in conjunction with the accompanying drawings, but these descriptions cannot be understood as limiting the scope of the present invention. The protection scope of the present invention is defined by the attached claims, and any changes based on the claims of the present invention are within the protection scope of the present invention.

Claims

1. A high-precision, vibration-resistant, large-aperture mechanical phase-shifting interferometry measurement method, characterized in that: The following steps are included: Step 1: Collect the interference fringe pattern of the measured surface through a large-aperture interferometer, obtain the phase distribution of the measured surface through principal component analysis, and calculate the true initial value of the phase shift; Step 2: Obtain the real background light intensity and modulation degree through the interference fringe pattern obtained in step 1; Step 3: Establish an error model of environmental vibration noise, and perform noise suppression based on the error model of environmental vibration noise; Step 4: Based on the background light intensity and modulation obtained in step 2, combined with the environmental vibration noise model established in step 3, an iterative linear regression algorithm is used to iteratively fit the phase shift plane and extract the phase to be measured, thereby achieving high-precision vibration-resistant large-aperture mechanical phase-shift interferometry.

2. A high-precision, vibration-resistant, large-aperture mechanical phase-shifting interferometry method as claimed in claim 1, characterized in that: The specific implementation method of step one is: The outgoing light beam of the interferometer host is reflected by the reference mirror TF and the standard mirror RF in turn to form reference light and measurement light. The reference light and measurement light return along the optical axis of the interferometer system. When the reference light and measurement light interfere with each other, interference fringes are formed. The light intensity of the interference pattern with environmental vibration noise is expressed as: Among them, A(x,y) represents the background light intensity of the interference fringes; V(x,y) represents the modulation degree of the interference fringes; It is represented by the wavefront phase distribution of the measurement light reflected by RF; δ(x, y, t) represents the phase shift amount. Environmental vibration causes the phase shift plane to tilt, which is expressed as: δ(x,y,t)=α n x+b n y+γ n (1) where α n , β n and γ n They represent the tilt phase shift coefficient and translation phase shift in the x and y directions caused by environmental vibration respectively; the phase distribution is quickly calculated by the principal component analysis algorithm The background light intensity and modulation degree in formula (1) do not change with the pixel, that is, A m (x,y)=a m ,B m (x,y)=b m , where a m and b m are two constants independent of pixels, expressed as: Among them C m (t0) = b m cosδ m (t0), S m (t0) = -b m sinδ m (t0); Since formula (3) for C m and S m is linear, and S is obtained by linear least squares method m (t0) and C m (t0), then the actual initial value of the phase shifter δ(t0) is obtained by the inverse tangent formula: The phase shift obtained by formula (4) is wrapped in the range of (-π, π]; the unwrapping criterion SD = δ m (n)-δ m (n-1), when |SD|<π, it is determined that δ(t0) is not wrapped.

3. A high-precision, vibration-resistant, large-aperture mechanical phase-shifting interferometry method as claimed in claim 2, characterized in that: The specific implementation method of step 2 is: According to the obtained interference pattern, the background light intensity A(x, y) and modulation V(x, y) in the interference pattern are extracted and expressed as: Where I(x,y,t) is the light intensity value of the interference pattern obtained by interfering the measured surface.

4. A high-precision, vibration-resistant, large-aperture mechanical phase-shifting interferometry measurement method as claimed in claim 3, characterized in that: Step three is the specific implementation method: Due to environmental vibration, the measurement cavity formed by the measured mirror and the reference mirror changes in real time; the noise model expression of the cavity structure is established: Among them, τ(t) is the phase shift over time; α(t) and β(t) are the tilt coefficients of the reference surface and the measured surface, and ρ(x) 2 =x 2 +y 2 , c is the phase curvature, when the measured surface is a plane, c=0; t0 represents the time of collecting the first interference pattern. The noise model of the cavity structure shown in formula (6) is the error model of the environmental vibration noise. The noise model of the cavity structure shown in equation (6) gives a new estimated value: Where subscript δ n (t), α n (t), β n (t) represents the new estimated value; δ'(t), α'(t), β'(t) represent the deviation values; Substituting equation (7) into equation (1), we can obtain the actual light intensity expression affected by the environment: in, K represents the iteration level, k represents the number of iterations, k = 1, 2, ... K; g represents the square root of the product of the reflectivity of the measured mirror and the reference mirror, which characterizes the reflection quality of the cavity. This value is greatly affected by the environment and is updated according to the increase in the number of iterations; the iterative evaluation function is expressed as: Wherein, M represents the number of phase shifts; by updating the time-related variables δ(t), α(t), β(t), and iteratively calculating the evaluation function, noise suppression is achieved.

5. According to the high-precision vibration-resistant large-aperture mechanical phase-shifting interferometry measurement method of claim 4, the specific implementation method of step 4 is: The background light intensity A(x, y), modulation V(x, y) obtained in step 2 and δ(x, t) obtained in step 3 are introduced into the MPSI iterative linear regression algorithm and expressed as: in, During the phase-shift interferometry measurement, the corresponding interference pattern is obtained according to the phase-shift times M, and the iterative parameter g is updated and optimized: Whether to continue the iterative calculation is determined by whether the iterative evaluation function χ(t) is lower than 0.1%. If the threshold condition is not met, the iterative evaluation function χ(t) is brought into step three and step four for further iterative update calculation, and the g value is continuously updated until it converges to the evaluation function threshold; thus, the wrapped phase of the measured surface shape is obtained.

6. A high-precision, vibration-resistant, large-aperture mechanical phase-shifting interferometry device for implementing the method of claim 1, 2, 3, 4 or 5, characterized in that: The invention comprises a laser, a beam splitter, a small-diameter collimator, a beam expander, a large-diameter collimator, a precision adjustment frame of a reference mirror, a reference mirror, a standard measured mirror, a precision adjustment frame of the standard measured mirror, a beam splitter prism, an imaging lens group and a CCD camera; a point light source emitted by a point light source passes through a beam splitter and then passes through a small-diameter collimator to obtain parallel light of a preset diameter, passes through a beam expander group and a large-diameter collimator to obtain parallel light of a preset enlarged diameter, one of the light beams is reflected by the rear surface of the reference mirror and then passes through the large-diameter collimator, the beam expander and the large-diameter collimator again. The reference light is formed after passing through the mirror group, the small-aperture collimator mirror and the beam splitter, and then reflected by the beam splitter prism; another beam of light passes through the reference mirror, is reflected by the front surface of the measured mirror, and then passes through the reference mirror, the large-aperture collimator mirror, the beam expander mirror group, the small-aperture collimator mirror and the beam splitter, and then reflected by the beam splitter prism to form the measuring light; when the reference light and the measuring light are coherently interfered, the interference pattern of the measured surface is collected by the interferometer; the high-precision phase solution is obtained according to the large-aperture high-precision phase-shifting interference anti-vibration measurement method, and the high-precision surface fitting is realized.

7. A high-precision, vibration-resistant, large-aperture mechanical phase-shifting interferometry device as claimed in claim 6, characterized in that: The point light source emitted by the point light source passes through the beam splitter and then passes through the small-aperture collimator to obtain parallel light with an aperture of 100 mm, and passes through the beam expander group and the large-aperture collimator to obtain parallel light with an aperture of 820 mm.

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