A forward design method of laser speckle interferometry measurement system

Abstract

The application discloses a kind of laser speckle interferometry system forward design method, through multidisciplinary collaborative design and verification, realize from measurement demand definition to system optimization design whole process closed loop. Specifically include: obtaining the deformation characteristics of target to be measured and working condition condition;Optimize laser illumination parameter to ensure light field uniformity;Based on scalar diffraction theory calculation object plane light field complex amplitude;Design and verify the optical and mechanical performance of detection optical system;Intelligent adjustment shear quantity adapts deformation gradient change;Using phase shift or carrier wave technology extracts phase information;Phase data is handled by iterative optimization algorithm;Finally, the measurement result is compared with theoretical value to realize error evaluation.The application innovatively combines finite element analysis, light field transmission simulation and algorithm optimization, significantly improves the system design efficiency and measurement accuracy, solves the problem that parameter configuration depends on experience in traditional method, and environmental adaptability is poor.It is especially suitable for the deformation precision measurement of large-scale structural member under complex working condition.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser speckle interferometry, and in particular relates to a forward design method for a laser speckle interferometry measurement system. Background Art

[0002] Laser speckle interferometry is an interferometric measurement technology mainly used for objects with non-smooth surfaces. It can generate laser speckle fields in combination with scattering screens, etc. It can also be used for objects with smooth surfaces to measure the deformation and first-order derivative of the object under service conditions. It is used for thermodynamic performance analysis, quality status monitoring, vibration analysis, etc. Compared with traditional displacement sensors, three-coordinate machines, strain sensors, etc., it has the advantages of non-contact, large field of view, and real-time.

[0003] Laser speckle interferometry (LSI) technology primarily encompasses two main branches: reference-light-based LSI and shearing-based LSI. Researchers have proposed a variety of improved technical solutions, encompassing aspects such as optical path systems and processing algorithms, to enhance the measurement field of view, real-time performance, and accuracy. However, in practical applications, LSI technology faces multiple challenges. On the one hand, the complexity of field conditions and the diversity of environmental interference pose a severe challenge to the implementation of technical solutions. The rational selection of technical solutions, the precise configuration of system parameters, and the accuracy of on-site calibration are all directly related to the reliability and validity of measurement results. Furthermore, because the technology involves multiple disciplines, including optics, structure, control, and algorithms, it requires the collaboration and integration of interdisciplinary teams. Currently, a systematic forward design application has not yet been established, both domestically and internationally. This not only increases the difficulty of system design and development but also places higher demands on the professional skills of on-site testers and operators.

[0004] Given these challenges, there is an urgent need to develop an efficient forward design methodology to scientifically guide the design and application of laser speckle interferometry systems. This methodology should comprehensively consider measurement requirements, field conditions, environmental interference, and multidisciplinary design requirements. Through refined design and optimization, it should ensure that the system can stably and accurately complete measurement tasks in practical applications. Furthermore, the forward design methodology should also encompass key aspects such as system reliability analysis, fault prediction, and diagnosis to enhance the system's overall performance and field adaptability, thereby meeting the growing demand for measurement. Summary of the Invention

[0005] To overcome the shortcomings of the above-mentioned existing technologies, the present invention provides a forward design method for a laser speckle interferometry measurement system. This method aims to achieve collaborative design and verification of multiple disciplines, including optics, mechanics, heat, force, and computation, for specific application objects. This method improves the efficiency of system design and development, and accelerates the process of field application debugging of the system. At the same time, it ensures that the measurement accuracy requirements for multi-scenario applications can be met during both the system development and field testing stages, thereby comprehensively improving the practicality and reliability of the system.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A forward design method for a laser speckle interferometry system comprises the following steps:

[0008] S1: Obtain measurement requirements: deformation / strain measurement accuracy, measurement range, etc. of the target to be measured;

[0009] S2: Obtaining deformation information of the target to be measured: Obtain basic information of the target to be measured, including material parameters, roughness, size, shape, etc., establish a finite element analysis model, and obtain deformation information of the target to be measured under different working loads according to the working state of the target to be measured, including deformation field distribution, deformation amount and deformation rate, etc. According to the size of the deformation area of ​​the target to be measured, determine the size of the effective detection area;

[0010] S3: Obtain on-site working conditions: Obtain on-site temperature and its changes, humidity, vibration and other environmental factors as well as the working space, and determine the lighting detection working distance;

[0011] S4: Laser illumination light field calculation: Based on the size of the effective detection area, the surface optical scattering characteristics, and the illumination detection working distance, determine the laser wavelength, power, polarization state, illumination angle and other parameters, carry out light field transmission simulation optimization, change the illumination angle, laser power, etc., to make the laser illumination light field in the effective detection area uniform;

[0012] S5: Calculation of the complex amplitude of the light field on the object surface: Based on the laser illumination light field, the basic information and deformation information of the target to be measured, a light field transmission simulation analysis is carried out based on scalar diffraction theory to obtain the complex amplitude of the light field on the object surface when the target to be measured is deformed under different workloads;

[0013] S6: Detection optical system design:

[0014] S6.1: Optical design of laser speckle detection module: Based on the complex amplitude of the object light field, on-site working conditions, overall technical plan, working distance, etc., and in combination with the effective detection area, design the laser speckle detection optical module, determine parameters such as optical magnification, image resolution, and image size, and obtain optical parameters such as the optical cutoff frequency and wavefront aberration of the laser speckle detection module;

[0015] S6.2: Laser speckle detection module structure design: Based on the optical design results of the laser speckle detection module, carry out the corresponding structural design to determine the structural dimensions, internal spatial posture relationship, machining accuracy, assembly accuracy, etc.

[0016] S6.3: Finite element analysis of the laser speckle detection module structure: Based on the on-site working conditions, perform finite element simulation of the laser speckle detection module to calculate the structural deformation and internal spatial position changes of the laser speckle detection module under conditions such as temperature and vibration;

[0017] S6.4: Optical Performance Analysis of the Laser Speckle Detection Module: Incorporate information such as structural deformation and internal spatial position changes into the optical design results of the laser speckle detection module to obtain optical parameters such as the optical cutoff frequency, wavefront aberration, and F / # of the laser speckle detection module under field conditions.

[0018] S7: Shear amount setting: According to the deformation information of the target to be measured, the shear amount in the X and Y directions is set according to the principle of "the greater the deformation gradient, the smaller the shear amount";

[0019] S8: Calculation of the light field complex amplitude of the reference optical path image plane: Based on the scalar diffraction theory, the optical frequency domain transfer function of the laser speckle detection module and the object plane light field complex amplitude of the target to be measured are used to perform light field transmission calculation and analysis to obtain the light field complex amplitude of the reference optical path image plane;

[0020] S8.1: Generate an optical frequency domain transfer function based on the optical cutoff frequency, wave aberration, etc. of the laser speckle detection module;

[0021] S8.2: Based on the optical magnification and image plane resolution of the laser speckle detection module, the complex amplitude of the object light field of the target to be measured is scaled and gridded twice to obtain the ideal complex amplitude of the light field of the target to be measured;

[0022] S8.3: Use the optical frequency domain transfer function to low-pass filter the spectrum of the target to be measured to obtain the complex amplitude of the light field on the reference optical path image plane;

[0023] S9: Calculation of the light field complex amplitude of the sheared optical path image plane: Based on the scalar diffraction theory and the shear amount setting results, combined with the optical frequency domain transfer function of the laser speckle detection module and the object plane light field complex amplitude of the target to be measured, the light field transmission calculation analysis is carried out. Referring to the calculation steps of the light field complex amplitude of the reference optical path image plane in S8, the light field complex amplitude of the sheared optical path image plane is obtained;

[0024] S10: Laser Speckle Interference Image Recording and Phase Extraction: Using time phase shifting or spatial carrier wave technology, the laser speckle interference image formed by the complex amplitude of the light field of the reference optical path image plane and the complex amplitude of the light field of the shear optical path image plane is recorded, and the phase of the laser speckle interference image is extracted. For multiple laser speckle interference images obtained by time phase shifting, the phase information is extracted according to the number of time phase shift steps; for a single laser speckle image obtained by spatial carrier wave acquisition, the phase information is extracted by Fourier transform calculation;

[0025] S11: Repeat steps S8-S10 to obtain phase information of the target before deformation and at different moments of deformation;

[0026] S12: Phase information subtraction: According to the measurement requirements, the series of phase information obtained in S11 are subtracted to obtain the parcel phase information containing noise;

[0027] S13: Determine the density of the wrapped phase information: When the fringes in the wrapped phase information in a certain shearing direction are dense, go to step S7, reduce the shear amount in that direction, and repeat steps S8-S12; when the fringes in the wrapped phase information in a certain shearing direction are sparse, go to step S7, increase the shear amount in that direction, and repeat steps S8-S12 until the shear amount setting can meet the measurement requirements of the deformation of the target at any time;

[0028] S14: Phase information filtering: performing noise filtering on the noisy parcel phase information obtained in S13, including but not limited to a sine-cosine mean filtering algorithm, a wavelet transform algorithm, a window Fourier filter algorithm, etc., to obtain the parcel phase information after noise removal;

[0029] S15: Phase information unwrapping: Unwrapping the denoised wrapped phase information obtained in S14, including but not limited to discrete cosine least squares method, branch cutting method, etc., to obtain unwrapped phase information;

[0030] S16: Strain information calculation: The unwrapped phase information obtained in S15 is combined with the shear amount setting result in S7, the laser wavelength, etc. to calculate the strain distribution measurement result;

[0031] S17: Error evaluation:

[0032] S17.1: Based on the shear amount setting result in S13, perform differential processing on the deformation information of the target to be measured in S2 to obtain the theoretical strain distribution;

[0033] S17.2: Spatially align the strain distribution measured in S16 with the theoretical strain distribution in S15.1, subtract the two to obtain the difference, and calculate the RMS value of the difference;

[0034] S18: Compare and analyze the RMS value of the difference with the measurement accuracy and other indicators of S1. If the requirements are met, the final design results including the optical and structural design scheme of the laser speckle interferometry measurement system, data acquisition and processing algorithm, and system parameter settings are output. If the requirements are not met, the optimization iterations are carried out in the following order:

[0035] S18.1: Change the phase unwrapping algorithm in step S15 and repeat steps S15-S18;

[0036] S18.2: Change the phase information filtering algorithm and its parameters in step S14, and repeat steps S14-S18;

[0037] S18.3: Change the phase information extraction method in step S10 and repeat steps S10-S18;

[0038] S18.4: Change the optical system design in step S6 and repeat steps S6-S18.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1) The method of the present invention realizes the whole chain design, analysis and evaluation process from "definition of the target to be measured" to "construction of the lighting detection system" and then to "data processing analysis and error evaluation".

[0041] 2) This invention integrates the target module to be measured with the laser illumination module. Through light field transmission simulation analysis, various parameters of the laser illumination module are adjusted to generate a high-quality, evenly distributed laser light field. This ensures the uniformity of the light field and the clarity of the speckle pattern during measurement, providing a solid foundation for subsequent measurements. Simultaneously, combined with the field operating condition module, finite element simulation analysis of the laser speckle detection structure module is performed, clarifying the relative deformation and spatial position relationship changes of the structure under different operating conditions. This ensures that the laser speckle detection optical module can maintain high accuracy and stability under real-world operating conditions.

[0042] 3) The complex amplitude of the object light field is combined with the optimized laser speckle detection optical module, and light field transmission simulation analysis is performed again to determine the deformation and strain of the target to be measured. At the same time, by introducing an error evaluation module, the system simulation measurement results are rigorously evaluated to ensure that the measurement results meet the preset accuracy requirements. Based on the error evaluation results, this method can guide the optimization and improvement of the laser illumination module, laser speckle detection optical module, data acquisition and processing module, and system parameter calibration module. Through multiple iterations, the system design and parameter settings are continuously optimized until the measurement accuracy requirements are met. This reduces the number of hardware design and manufacturing iterations and the number of system parameter debugging times during field measurements, significantly improving the design iteration efficiency and the system's field applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is the flowchart of the forward design method of the laser speckle interferometry system of the present application.

[0044] Figure 2 is the maximum deformation of the measured target at the first moment of the embodiment of the present application.

[0045] Figure 3 is the maximum deformation of the measured target at the second moment of the embodiment of the present application.

[0046] Figure 4 is the series of speckle interferograms of the measured target before deformation when the system F / # = 16 of the embodiment of the present application.

[0047] Figure 5 is the phase information of the measured target before deformation when the system F / # = 16 of the embodiment of the present application.

[0048] Figure 6 is the series of speckle interferograms of the measured target deformed by 1 μm when the system F / # = 16 of the embodiment of the present application.

[0049] Figure 7 is the phase information of the measured target deformed by 1 μm when the system F / # = 16 of the embodiment of the present application.

[0050] Figure 8 is the wrapped phase information of the measured target deformed by 1 μm relative to that before deformation (X direction shear amount 20 mm) when the system F / # = 16 of the embodiment of the present application.

[0051] Figure 9 is the series of speckle interferograms of the measured target deformed by 50 μm when the system F / # = 16 of the embodiment of the present application.

[0052] Figure 10 is the phase information of the measured target deformed by 50 μm when the system F / # = 16 of the embodiment of the present application.

[0053] Figure 11 is the wrapped phase information filtering result of the measured target deformed by 50 μm relative to that before deformation (X direction shear amount 20 mm) when the system F / # = 16 of the embodiment of the present application.

[0054] Figure 12 is the ideal strain distribution of the measured target (X direction shear amount 5 mm) when the system F / # = 16 of the embodiment of the present application.

[0055] Figure 13This is the wrapped phase information filtering result, strain distribution measurement result, and measurement error (X-direction shear amount 5mm) of the target deformation 50μm before deformation for the system of the embodiment of the present invention when F / #=16.

[0056] Figure 14 When the system F / # is 6, the following are the wrapped phase information filtering results, strain distribution measurement results, and measurement error (X-direction shear amount 5mm) of the target deformation 50μm before deformation: DETAILED DESCRIPTION

[0057] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention shall not be limited thereto.

[0058] See also Figure 1 , Figure 1 1 is a flow chart of the forward design method of the laser speckle interferometry measurement system of the present invention, which includes the following steps:

[0059] S1: Obtain measurement requirements: The RMS value of the target strain measurement error is ≤4×10 -6 , measuring range ≥10 -4 ;

[0060] S2: Obtaining deformation information of the target to be measured: Obtain basic information of the target to be measured. The effective detection area size is 600mm×600mm, and the surface roughness is 0.72μm. A finite element analysis model is established, and the deformation of the target to be measured caused by force loading at two time points is obtained. The maximum deformation at the first time point is 1μm, and the maximum deformation at the second time point is 50μm. The deformation distribution is rotationally symmetric and approximately Gaussian, so single-direction measurement is sufficient.

[0061] S3: Obtain on-site working conditions: Obtain on-site temperature and its changes, humidity, vibration and other environmental factors as well as the working space, and determine that the lighting detection working distance is 1800mm;

[0062] S4: Laser illumination light field calculation: Based on the size of the effective detection area, the surface optical scattering characteristics, and the illumination detection working distance, the laser wavelength is determined to be 532nm, the power is 300mW, the polarization state is P, and the illumination is paraxial.

[0063] S5: Calculation of the complex amplitude of the object light field: Based on the laser illumination light field, the basic information of the target to be measured, and the deformation information, a light field transmission simulation analysis is carried out based on scalar diffraction theory to obtain the complex amplitude of the object light field when the target to be measured is deformed.

[0064] S6: Detection optical system design:

[0065] S6.1: Optical design of laser speckle detection module: Based on the complex amplitude of the object light field, on-site working conditions, overall technical plan, working distance, and the effective detection area size requirements, a laser speckle detection optical module was designed. The image plane resolution was 2800×2800, the image plane size was 7.672mm×7.672mm, and the optical magnification was calculated as image plane size / effective detection area size. The optical parameters of the laser speckle detection module, including optical cutoff frequency, wavefront aberration, and F / #, were obtained, where F / #=16.

[0066] S6.2: Laser Speckle Detection Module Structural Design: Based on the optical design results of the laser speckle detection module, carry out the corresponding structural design, determine the structural dimensions, internal spatial posture relationship, machining accuracy, assembly accuracy, etc.

[0067] S6.3: Finite element analysis of the laser speckle detection module structure: Based on the on-site working conditions, perform finite element simulation of the laser speckle detection module to calculate the structural deformation and internal spatial position changes of the laser speckle detection module under conditions such as temperature and vibration;

[0068] S6.4: Optical Performance Analysis of the Laser Speckle Detection Module: Incorporate information such as structural deformation and internal spatial posture changes into the optical design results of the laser speckle detection module to obtain optical parameters such as the optical cutoff frequency and wavefront aberration of the laser speckle detection module under field conditions. The optical system defocus is 10 μm.

[0069] S7: Shear amount setting: According to the deformation information of the target to be measured, the initial shear amount in the X direction is set to 20mm according to the principle of "the larger the deformation gradient, the smaller the shear amount";

[0070] S8: Calculation of the light field complex amplitude of the reference optical path image plane: Based on the scalar diffraction theory, the optical frequency domain transfer function of the laser speckle detection module and the object plane light field complex amplitude of the target to be measured are used to perform light field transmission calculation and analysis to obtain the light field complex amplitude of the reference optical path image plane;

[0071] S8.1: Generate the optical frequency domain transfer function based on the optical cutoff frequency, wave aberration, etc. of the laser speckle detection module;

[0072] S8.2: Based on the optical magnification and image plane resolution of the laser speckle detection module, the complex amplitude of the object light field of the target to be measured is scaled and gridded twice to obtain the ideal complex amplitude of the light field of the target to be measured;

[0073] S8.3: Use the optical frequency domain transfer function to low-pass filter the spectrum of the target to be measured and obtain the complex amplitude of the light field on the image plane of the reference optical path;

[0074] S9: Calculation of the light field complex amplitude of the sheared optical path image plane: Based on the scalar diffraction theory and the shear amount setting results, combined with the optical frequency domain transfer function of the laser speckle detection module and the object plane light field complex amplitude of the target to be measured, the light field transmission calculation analysis is carried out. Referring to the calculation steps of the light field complex amplitude of the reference optical path image plane in S8, the light field complex amplitude of the sheared optical path image plane is obtained;

[0075] S10: Laser Speckle Interference Image Recording and Phase Extraction: Carre’s equal-step temporal phase shifting technique is used to record the laser speckle interference image formed by the complex amplitude of the light field on the reference optical path image plane and the complex amplitude of the light field on the shear optical path image plane, and extract the phase information;

[0076] S11: Repeat steps S8-S10 to obtain phase information of the target before deformation, at minimum deformation, and at maximum deformation respectively;

[0077] S12: Phase information subtraction: Subtract the phase information after deformation obtained in S11 from the phase information before deformation of the target to be measured to obtain the wrapped phase information containing noise;

[0078] S13: Determine the density of the wrapped phase information: When the shearing amount is 20 mm, the fringes in the wrapped phase information are dense, so go to step S7 to reduce the shearing amount, and repeat steps S8-S13 until the shearing amount is set to 5 mm to meet the deformation measurement requirements at different times;

[0079] S14: Phase information filtering: The noisy wrapped phase information obtained in S13 is subjected to noise filtering using a sine-cosine mean filtering algorithm, with a filter window of 5×5 and 5 iterations;

[0080] S15: Phase information unwrapping: The denoised wrapped phase information obtained in S14 is unwrapped using a discrete cosine least squares method to obtain unwrapped phase information;

[0081] S16: Strain information calculation: The unwrapped phase information obtained in S15 is combined with the shear amount setting result in S7, the laser wavelength, etc. to calculate the strain distribution measurement result;

[0082] S17: Error evaluation:

[0083] S17.1: Based on the shear amount setting result in S13, perform differential processing on the deformation information of the target to be measured in S2 to obtain the theoretical strain distribution;

[0084] S17.2: Spatially align the strain distribution measured in S16 with the ideal strain distribution in S17.1, subtract the two to obtain the difference, and calculate the RMS value of the difference;

[0085] S18: Compare and analyze the RMS value of the difference with the measurement accuracy and other requirements of S1, and successively change the phase unwrapping algorithm, phase information filtering algorithm and its parameters, and the optical performance of the detection optical system. When F / #=6, other algorithms and parameters remain unchanged, and the RMS value of the strain measurement error is 1.23με, which meets the requirements. Then, output the complete design results, including the optical and structural design scheme of the laser speckle interferometry measurement system, data acquisition and processing algorithm, and system parameter settings.

Claims

1. A forward design method for a laser speckle interferometry system, characterized in that: The following steps are involved: S1: Obtain measurement requirements, including deformation of the target, strain measurement accuracy and measurement range; S2: Obtain deformation information of the target to be measured, including material parameters, roughness, size, and shape, establish a finite element analysis model, obtain deformation information of the target to be measured under different working loads according to the working state of the target to be measured, and determine the size of the effective detection area; S3: Obtain on-site working conditions, including on-site temperature and its changes, humidity, vibration and other environmental factors, as well as the working space, to determine the lighting detection working distance; S4: Laser illumination light field calculation: Determine the laser wavelength, power, polarization state, and illumination angle based on the effective detection area size, surface optical scattering characteristics, and illumination detection working distance, and optimize the uniformity of the laser illumination light field through light field transmission simulation; S5: Calculation of the complex amplitude of the light field on the object surface: Based on the laser illumination light field, the basic information and deformation information of the target to be measured, a light field transmission simulation analysis is carried out based on scalar diffraction theory to obtain the complex amplitude of the light field on the object surface when the target to be measured is deformed under different workloads; S6: Design of detection optical system, including optical module design, structural design, structural finite element analysis and optical performance analysis; S7: According to the deformation information of the target to be measured, the shear amount in the X and Y directions is set respectively according to the principle of "the deformation gradient is inversely proportional to the shear amount"; S8: Calculate the complex amplitude of the light field on the image plane of the reference optical path based on scalar diffraction theory and optical frequency domain transfer function; S9: Calculate the complex amplitude of the light field on the image plane of the shearing optical path by combining the set shearing amount and the optical transfer function; S10: Using a technique such as temporal phase shifting or spatial carrier wave, a laser speckle interferometer image formed by the complex amplitude of the light field of the reference optical path image plane and the complex amplitude of the light field of the sheared optical path image plane is recorded, and phase extraction is performed on the laser speckle interferometer image. For multiple laser speckle interferometer images acquired by temporal phase shifting, phase information is extracted based on the number of temporal phase shift steps; for a single laser speckle image acquired by spatial carrier wave, phase information is extracted by Fourier transform calculation. S11: Repeat steps S8-S10 to obtain phase information of the target before deformation and at different moments of deformation; S12: Subtracting the phase information after deformation from the phase information before deformation to obtain the wrapped phase information containing noise; S13: Determine the density of the wrapped phase information: When the fringes in the wrapped phase information in a certain shearing direction are dense, go to step S7, reduce the shear amount in that direction, and repeat steps S8-S12; when the fringes in the wrapped phase information in a certain shearing direction are sparse, go to step S7, increase the shear amount in that direction, and repeat steps S8-S12 until the shear amount setting can meet the measurement requirements of the deformation of the target at any time; S14: performing noise filtering on the parcel phase information containing noise obtained in S13 to obtain parcel phase information after noise removal; S15: unwrapping the denoised wrapped phase information obtained in S14 to obtain unwrapped phase information; S16: Calculate the strain distribution measurement results based on the unwrapped phase information obtained in S15, combined with the final shear amount setting and laser wavelength parameters; S17: Perform error analysis between the measured strain distribution and the theoretical strain distribution; S18: Compare and analyze the RMS value of the difference with the measurement accuracy and other index requirements of S1. If the requirements are met, the complete design result is finally output; If the requirements are not met, iterative optimization is performed according to the preset optimization order.

2. The forward design method of the laser speckle interferometry system according to claim 1, characterized in that: The step S6: detecting the design of the optical system, specifically includes: S6.1: Optical design of laser speckle detection module: Based on the complex amplitude of the object light field, on-site working conditions, overall technical plan, working distance, etc., and in combination with the effective detection area, design the laser speckle detection optical module, determine parameters such as optical magnification, image resolution, and image size, and obtain optical parameters such as the optical cutoff frequency and wavefront aberration of the laser speckle detection module; S6.2: Laser speckle detection module structure design: Based on the optical design results of the laser speckle detection module, carry out the corresponding structural design to determine the structural dimensions, internal spatial posture relationship, machining accuracy, assembly accuracy, etc. S6.3: Finite element analysis of the laser speckle detection module structure: Based on the on-site working conditions, perform finite element simulation of the laser speckle detection module to calculate the structural deformation and internal spatial position changes of the laser speckle detection module under conditions such as temperature and vibration; S6.4: Optical Performance Analysis of the Laser Speckle Detection Module: Incorporate information such as structural deformation and internal spatial posture changes into the optical design results of the laser speckle detection module to obtain optical parameters such as the optical cutoff frequency, wavefront aberration, and F / # of the laser speckle detection module under field conditions.

3. The forward design method of the laser speckle interferometry system according to claim 1, characterized in that: The step S8: calculating the complex amplitude of the object plane light field of the target to be measured based on scalar diffraction theory and optical frequency domain transfer function, specifically includes: S8.1: Generate an optical frequency domain transfer function based on the optical cutoff frequency, wave aberration, etc. of the laser speckle detection module; S8.2: Based on the optical magnification and image plane resolution of the laser speckle detection module, the complex amplitude of the object light field of the target to be measured is scaled and gridded twice to obtain the ideal complex amplitude of the light field of the target to be measured; S8.3: Use the optical frequency domain transfer function to low-pass filter the spectrum of the target to be measured to obtain the complex amplitude of the light field on the reference optical path image plane.

4. The forward design method of the laser speckle interferometry system according to claim 1, characterized in that: The filtering algorithm selection criteria in step S14 include: For high frequency noise, wavelet transform filtering is used; For periodic noise, window Fourier filtering is used; For local outliers, sine and cosine mean filtering is used; Dynamically adjust the filter window size according to the signal-to-noise ratio.

5. The forward design method of the laser speckle interferometry system according to claim 1, characterized in that: The unpacking algorithm selection criteria in step S15 include: For the continuous phase field, the least square method is used; For regions with phase mutations, the branch cutting method was used; The unwrapping path is dynamically selected based on the phase quality map.

6. The forward design method of the laser speckle interferometry system according to claim 1, characterized in that: The step S17: performing error analysis between the measured strain distribution and the theoretical strain distribution, specifically includes: S17.1: Based on the shear amount setting result in S13, perform differential processing on the deformation information of the target to be measured in S2 to obtain the theoretical strain distribution; S17.2: Spatially align the strain distribution measured in S16 with the theoretical strain distribution in S15.1, subtract the two to obtain the difference, and calculate the RMS value of the difference.

7. The forward design method of the laser speckle interferometry system according to claim 1, characterized in that: The priority of the optimization order in step S18 is: Level 1: Adjust the phase unwrapping algorithm parameters; Level 2: Replace the phase filtering algorithm and optimize the parameters; Level 3: Modify the phase extraction method; Level 4: Optimize optical system design parameters; After each optimization, steps S6-S17 need to be re-executed for verification.

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