Wide-range high-resolution deformation measurement method and device

Abstract

The embodiment of the invention discloses a wide-range high-resolution deformation measurement method and device. The method comprises the steps that a dual-wavelength space carrier digital shearing speckle interference measurement light path is established; determining phase distribution of an out-of-plane deformation gradient according to a dual-wavelength space carrier digital shear speckle interference measurement light path; determining absolute phase change of the out-of-plane deformation gradient according to the phase distribution of the out-of-plane deformation gradient; according to the absolute phase change of the out-of-plane deformation gradient, determining the gradient change generated by the whole-field whole-process deformation; and determining full-field out-of-plane deformation according to the gradient change generated by the full-field and full-process deformation.

Description

Technical Field

[0001] The present disclosure relates to the field of full-field optical measurement technologies, and in particular, to a dual-wavelength digital shearography technology for wide-range and high-resolution deformation measurement. Background Art

[0002] Digital shearography technology, with its common-path design and unique advantage of not requiring an additional reference light, demonstrates strong application potential in industrial on-site inspections, and is particularly suitable for qualitative inspections and quantitative measurements of surface displacement gradients in fields such as rubber tire evaluation and aerospace structure evaluation. However, traditional digital shearography technology has significant limitations in dealing with the deformation of large-sized objects, mainly manifested as limited measurement range and difficulty in accurately restoring the deformation field.

[0003] For micro-deformations in the range of hundreds of nanometers to micrometers, digital shearography technology can accurately present the results in the form of phase information, providing important data support for engineering applications. However, when dealing with sub-millimeter deformations in areas of dozens to hundreds of square centimeters, the measurement range of traditional digital shearography technology is insufficient. The original phase only contains spatial displacement gradient information and needs to be converted to restore the deformation field. In addition, it is difficult to determine the boundary starting conditions during the integration process from the gradient to the displacement, making the accurate measurement of the out-of-plane deformation field complex and challenging. Summary of the Invention

[0004] An embodiment of the present application proposes a wide-range and high-resolution deformation measurement method and device, which expands the measurement range of digital shearography and is applicable to wide-range and high-resolution deformation measurement.

[0005] An embodiment of the present application provides a wide-range and high-resolution deformation measurement method, including:

[0006] Constructing a dual-wavelength spatial carrier digital shearography measurement optical path;

[0007] Determining the phase distribution of the out-of-plane deformation gradient according to the dual-wavelength spatial carrier digital shearography measurement optical path;

[0008] Determining the absolute phase change of the out-of-plane deformation gradient according to the phase distribution of the out-of-plane deformation gradient;

[0009] Determining the gradient change generated by the full-field and whole-process deformation according to the absolute phase change of the out-of-plane deformation gradient;

[0010] Determining the full-field out-of-plane deformation according to the gradient change generated by the full-field and whole-process deformation.

[0011] Optionally, the dual-wavelength spatial carrier digital shearography measurement optical path includes two lasers with different wavelengths, a diaphragm, an imaging lens, and a shearing device;

[0012] The two lasers with different wavelengths irradiate the surface of the object to be measured with laser light output at symmetric angles simultaneously, and their diffuse reflection light passes through the diaphragm, imaging lens, and shear module respectively, and is finally received by the image sensor;

[0013] The shear module is used to determine the shear direction, introduce the shear amount, and introduce the spatial carrier amount. Among them, the spatial carrier amount and the two different laser wavelengths jointly determine the distribution of the interference spectrum.

[0014] Optionally, in the double-wavelength spatial carrier digital shearography optical path, lasers with different wavelengths are used as light sources, the two-way laser illumination angles are equal and symmetrically placed, and the phase distribution of the out-of-plane deformation gradient is extracted through the frequency domain.

[0015] Optionally, according to the phase distribution of the out-of-plane deformation gradient, determining the absolute phase change of the out-of-plane deformation gradient includes:

[0016] Performing spatio-temporal phase unwrapping processing on all phase difference map information during the acquisition process;

[0017] The spatio-temporal phase unwrapping processing restores the absolute phase change of the out-of-plane deformation gradient from the perspective of the combination of one-dimensional time and two-dimensional spatial phase difference information.

[0018] Optionally, according to the spatio-temporal phase unwrapping algorithm, determining the absolute phase change value of the deformation gradient of the measured surface includes:

[0019] Performing temporal phase unwrapping on the wrapped phase map to determine the phase change of the selected reference point on the time axis;

[0020] Performing spatial phase unwrapping on the wrapped phase map to determine the spatial phase difference value of each sampling interval;

[0021] According to the phase change of the reference point on the time axis and the spatial phase difference value within each sampling interval, determining the absolute phase change of the full-field deformation.

[0022] Optionally, according to the phase change of the reference point on the time axis and the spatial phase difference value of each sampling interval, determining the absolute phase change of the full-field deformation includes:

[0023] According to the phase change of the selected reference point on the time axis and the spatial phase difference value of each sampling interval, determining the spatial phase change value with time information;

[0024] According to the spatial phase change value with time information, determining the absolute phase change of the deformation.

[0025] Optionally, according to the absolute phase change of the out-of-plane deformation gradient, determining the gradient change generated by the full-field and whole-process deformation includes:

[0026] After selecting the region of interest, find the point with the lowest phase change frequency as the reference point to determine the absolute time phase change;

[0027] The spatial phases at different times are unwrapped starting from the absolute time phase at that time to determine the full-field unwrapped phase diagrams at different times;

[0028] According to the full-field unwrapped phase diagrams at different times, determine the gradient changes generated by the full-field deformation throughout the process.

[0029] Optionally, according to the gradient changes generated by the full-field deformation throughout the process, determine the out-of-plane deformation of the whole field, including:

[0030] Establish a model of a rectangular test piece with its four sides fixed, and determine the boundary conditions for the integration of the displacement space gradient at the four sides of the rectangle;

[0031] Either the horizontal or vertical side of the rectangular test piece can be used as the integration starting point, and the displacement value at the integration starting point is set to 0, and the integration path is along the shear direction.

[0032] Optionally, a network model of two-dimensional data is used for finite difference solution for the calculation of large shear measurement results, including:

[0033] According to the two-dimensional network model, based on the relationship between each surface topography data point and the surrounding slope data points, determine the network model;

[0034] According to the finite difference method, solve along the shear direction to determine the out-of-plane deformation information.

[0035] The embodiment of the present application also provides a device for wide-range and high-resolution deformation measurement, including:

[0036] A building module for building a double-wavelength spatial carrier digital shear speckle interferometry measurement optical path;

[0037] A first determination module for determining the phase distribution of the out-of-plane deformation gradient;

[0038] A second determination module for determining the absolute phase change of the out-of-plane deformation gradient;

[0039] A third determination module for determining the gradient changes generated by the full-field deformation throughout the process;

[0040] A fourth determination module for determining the out-of-plane deformation of the whole field. Description of the Drawings

[0041] The accompanying drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The schematic embodiments and descriptions thereof of the present application are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0042] Figure 1 is a schematic flow chart of a wide-range and high-resolution deformation measurement method according to an embodiment of the present disclosure;

[0043] Figure 2 is a schematic diagram of the principle of a dual-wavelength spatial carrier digital shearography measurement optical path according to an embodiment of the present disclosure;

[0044] Figure 3 is a structural diagram of a dual-wavelength spatial carrier digital shearography measurement optical path according to an embodiment of the present disclosure;

[0045] Figure 4 is a schematic flow chart of a spatio-temporal three-dimensional phase unwrapping process according to an embodiment of the present disclosure.

[0046] Figure 5 is a schematic flow chart of a spatio-temporal three-dimensional unwrapping to restore the absolute phase of out-of-plane deformation according to an embodiment of the present disclosure;

[0047] Figure 6 is a gradient change value diagram of the deformation generated throughout the whole field and the whole process according to an embodiment of the present disclosure;

[0048] Figure 7 is a schematic diagram of a displacement restoration integration method according to an embodiment of the present disclosure;

[0049] Figure 8 is a diagram of the absolute out-of-plane deformation value of the whole field according to an embodiment of the present disclosure;

[0050] Figure 9 is a block diagram of a wide-range and high-resolution deformation measurement device according to an embodiment of the present disclosure. Detailed Embodiments

[0051] The following will describe in detail various exemplary embodiments, features, and aspects of the present disclosure with reference to the accompanying drawings. The same reference numerals in the drawings denote elements having the same or similar functions. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0052] The special term "exemplary" herein means "serving as an example, embodiment, or illustrative". Any embodiment described as "exemplary" here does not have to be construed as superior to or better than other embodiments.

[0053] In addition, to better illustrate the present disclosure, numerous specific details are given in the following detailed implementation manners. Those skilled in the art should understand that the present disclosure can also be implemented without some specific details. In some instances, methods, means, elements, and circuits well-known to those skilled in the art are not described in detail so as to highlight the gist of the present disclosure.

[0054] The original phase of digital shear speckle interferometry only contains spatial displacement gradient information and needs to be converted with constraint conditions to restore the measured deformation field. Therefore, to meet the precise measurement of the deformation field in engineering, digital shear speckle interferometry technology also needs to achieve effective displacement integration and expand its displacement measurement range. This application proposes a dual-wavelength digital shear speckle interferometry technology for wide-range and high-resolution deformation measurement, which uses the method of spatio-temporal phase unwrapping to determine the absolute phase information of the entire field, so as to continuously record the displacement gradient changes in the whole process of deformation through multi-step measurement, and uses boundary constraint conditions to integrate and restore the out-of-plane deformation of the whole field. Based on the wide-range and high-resolution deformation measurement method provided by the embodiments of the present disclosure, the measurement range of digital shear speckle interferometry can be effectively expanded, the dynamic measurement of out-of-plane deformation can be realized, it is insensitive to rigid body displacement, and it is more suitable for on-site measurement.

[0055] Figure 1 The flowchart showing a wide-range and high-resolution deformation measurement method according to an embodiment of the present disclosure is as follows.

[0056] Step 102, set up a dual-wavelength spatial carrier digital shear speckle interferometry measurement optical path.

[0057] Step 104, determine the phase distribution of the out-of-plane deformation gradient according to the dual-wavelength spatial carrier digital shear speckle interferometry measurement optical path.

[0058] Step 106, determine the absolute phase change of the out-of-plane deformation gradient according to the phase distribution of the out-of-plane deformation gradient.

[0059] Step 108, determine the gradient change generated by the deformation of the whole field and the whole process according to the absolute phase change of the out-of-plane deformation gradient.

[0060] Step 110, determine the out-of-plane deformation of the whole field according to the gradient change generated by the deformation of the whole field and the whole process.

[0061] Figure 2 The schematic diagram showing a dual-wavelength spatial carrier digital shear speckle interferometry measurement optical path according to an embodiment of the present disclosure is shown. Figure 3 The structural diagram showing a dual-wavelength spatial carrier digital shear speckle interferometry measurement optical path according to an embodiment of the present disclosure is shown. As Figure 2 、 Figure 3As shown, the optical path is divided into two parts. These two parts of the optical path share an imaging lens, a diaphragm, and a Michelson shearing device. The optical path corresponding to laser 1 is referred to as the first optical path in the embodiments of the present disclosure, and the optical path corresponding to laser 2 is called the second optical path. Since the laser wavelengths of laser 1 and laser 2 are different, the sensitive vectors of the two optical paths to the deformation of the object to be measured are different.

[0062] Taking the first optical path as an example, a beam of laser light emitted from laser 1, after being expanded by an expander, is uniformly irradiated on the surface of the object to be measured and undergoes diffuse reflection. The reflected light carries information about the object to be measured. After passing through the diaphragm and the imaging lens, it enters the Michelson shearing device. The positions of the diaphragm and the imaging lens can be interchanged, and finally, it is collected by an image sensor (such as a CCD). This shearing device consists of two plane mirrors and a beam splitter prism. The light returning from the diffuse reflection forms a laterally displaced shearing speckle interference pattern in the shearing device. The functions of this shearing device are as follows: one is to generate a laterally displaced shearing speckle interference image, and the other is to adjust the shearing spectrum shift, so as to separate the high-frequency information from the low-frequency background light information. By performing a series of calculations such as Fourier transform on the high-frequency terms, the phase information of the shearing speckle interference can be obtained.

[0063] Based on the measurement principle of the shearing speckle interference technology, when the illumination direction of the expanded laser is in the xoz plane and the incident angle is ɑ, the relationship between the phase difference and the displacement spatial gradient in the x direction can be expressed as:

[0064]

[0065] Similarly, the formula in the y direction can be obtained:

[0066]

[0067] are the displacement spatial gradients of the in-plane displacement component u in the x and y shearing directions respectively, are the displacement spatial gradients of the out-of-plane deformation component w in the x and y shearing directions respectively. In an actual measurement system, parameters such as the laser wavelength, the shearing direction and amount, and the illumination angle can all be obtained. Then, only by extracting the interference phase information can the measurement of the displacement spatial gradient be realized.

[0068] When the measurement system is in the xoz plane and the incident angle is -α, the relationship between the phase difference and the displacement spatial gradient in the x direction can be expressed as:

[0069]

[0070] Such as Figure 3The dual-wavelength spatial carrier digital shearing speckle interferometer optical path shown in the figure has two beams of light that illuminate simultaneously, and a camera is used to record the images before and after deformation, capturing the interference images generated by different laser bands. Since the positions of high-frequency information in different bands are different in the frequency domain, the phase difference images △1 and △2 of each of the two paths can be directly extracted from them, and then the distribution of displacement derivatives can be obtained using these two phase images. When the illumination is in the xoz plane, the illumination angle is ɑ, and the shear angle is in the x direction, the relationship between the spatial derivative and the phase difference of the displacement component inside and outside the plane is expressed as:

[0071]

[0072] Among them, δ x is the shear amount in the x direction, is the spatial gradient of the in-plane displacement component u in the x-shear direction, is the spatial gradient of the displacement of the off-plane deformation component in the x-shear direction, △1 and △2 are the phase difference information obtained by the left and right interference light paths, and λ1 and λ2 are the wavelengths of the laser light sources used in the left and right interference light paths. Adding equations (1) and (2) gives the expression of the displacement gradient in the w direction:

[0073]

[0074] Formula (6) represents the in-plane displacement gradient calculated from two phase difference images within a single sampling interval. If you want to obtain the measurement result of large displacement, you need to process all the phase difference image information during the acquisition process in two steps: the first is to restore the absolute phase change of the off-plane deformation gradient from the perspective of combining one-dimensional time and two-dimensional space phase difference information; the second is to use a fixed edge as the starting point and the shear direction as the integration direction to integrate and obtain the final displacement measurement result.

[0075] Continuous deformation of the object under test will cause a sharp change in its spatial derivative. Observing the phase change caused by deformation from the time dimension can avoid the problem of drastic changes in spatial gradients that are difficult to unwrap, and thus adjust the sampling frequency according to the rate of deformation to obtain the phase. In the phase diagram, the phase change is represented by a grayscale value of 0-255, and the phase value caused by the deformation represented by it will be wrapped in [0, 2π). When observing out-of-plane deformation, the corresponding maximum optical path difference is λ / 2, that is, if the optical path difference caused by the out-of-plane deformation exceeds the maximum value within a single sampling interval, the phase unwrapping will fail. Therefore, according to the Nyquist sampling theorem and experimental experience, the camera sampling rate f is required. t At least 4 sampling points need to be sampled in one phase cycle. According to the off-plane deformation rate of the object, the sampling rate in the time dimension t can be obtained as shown in the following formula:

[0076]

[0077] Where N frame is the number of sampling frames, Δt is the time interval, k is an integer greater than 2, is the deformation rate.

[0078] Figure 4 A schematic flow chart showing a spatiotemporal three-dimensional phase unwrapping process according to an embodiment of the present disclosure.

[0079] Although temporal phase unwrapping cannot be used for the entire field, it can provide absolute phase values; although spatial phase unwrapping cannot calculate the absolute phase, it can provide good phase unwrapping effects. The spatiotemporal three-dimensional unwrapping algorithm combines the above two unwrapping algorithms and can calculate the absolute phase changes of the entire field.

[0080] In two-dimensional space, the size of the phase map is set to M×N, and the wrapped phase value is Φ w_s In the time dimension, the wrapped phase value of a point in the phase diagram is Φ w_t .

[0081] In the spatial two-dimensional wrapped phase diagram, the special area is selected as S, and the selection rule is:

[0082] S[(M×N)]=(m,n), (m1,n1), 1≤n≤N, 1≤m≤M (8)

[0083] Then the time phase unwrapping process is performed on the points in the selected area:

[0084]

[0085] Among them, Φ u_s(i) (M×N) is the total wrapped phase value in the wrapped phase diagram, Φ w_s (m, n) is the wrapped phase value selected by special rules.

[0086] Apply the time phase unwrapping algorithm to all points in the selected region:

[0087] U t [m, n] = Φ u_t (m,n) (10)

[0088] Among them U t is the time phase unwrapping algorithm, Φ u_t (m, n) is the phase value after time phase unwrapping of the points in the selected area.

[0089] Among the phase points that have completed time phase unwrapping, select Φ u_t The point (m) closest to the true phase in (m, n) * , n * ),Right now

[0090] C[Φ u_t (m, n)] = Φ u_t (m * , n * ) (11)

[0091] The point (m * , n * ) is the reference point of the wrapped phase diagram.

[0092] Subtract the spatial wrapped phase value of the reference point (m * , n * ) from the time phase unwrapped value to obtain Δ i

[0093] Δ i = Φ u_t(i) (m * , n * ) (i) - Φ w_s(i) (m * , n * ) (i) (12)

[0094] Take the point (m * , n * ) as the starting point in the two-dimensional space at different times respectively, and perform spatial phase unwrapping, that is

[0095] U s [Φ w_s(i) (M × N) (i) = Φ u_s(i) (M × N) (i) (i = 1, 2, 3,..., T) (13)

[0096] where U s is the spatial phase unwrapping algorithm, T is the last time, Φ w_s(i) (M × N) (i) is the wrapped phase solution value in the two-dimensional space plane at the i-th time, and Φ u_s(i) (M × N) (i) is the spatial unwrapped phase value at the i-th time.

[0097] Compensate Δ i into the spatial phase unwrapped value to obtain the final phase unwrapped value, that is

[0098] Φ u(i) = Φ u_s(i) (M × N) (i) + Δ i (14)

[0099] Figure 5Schematic flowchart showing a process of using spatio-temporal three-dimensional phase unwrapping to restore the out-of-plane deformation absolute phase according to an embodiment of the present disclosure.

[0100] The absolute phase change data of the displacement gradient of the measured surface is mainly processed for phase information by spatio-temporal phase unwrapping. Temporal phase unwrapping unfolds the phase change value of a single pixel point along the time axis, which is an unfolding of a one-dimensional algorithm. Spatial phase unwrapping involves the comparison of the phase values of adjacent pixel points, which can be further divided into path-dependent methods and path-independent methods. Spatio-temporal phase unwrapping (STPU) unfolds the phase at a selected reference point along the time axis and unfolds the entire phase map along the 2D spatial domain, thereby forming a dynamic phase difference map. In this method, the phase difference information extracted from the first optical path and the second optical path is processed separately, and the processing methods of the phase difference maps of the two paths are the same. Therefore, one of the paths is taken as an example for discussion.

[0101] Dynamically restore the phase change of the entire deformation process. Based on the phase change within each sampling interval along the time axis, perform temporal unwrapping and spatial unwrapping on the wrapped phase map respectively to obtain the phase change φ of the reference point along the time axis t and the spatial phase difference Δφ of each sampling interval x . Within one sampling interval, compensate the spatial phase value with the temporal phase change of the reference point, thereby forming a spatial phase change value with time information.

[0102] Unwrap the spatio-temporal phase of each sampling interval one by one along the time axis to obtain the absolute phase change of the deformation:

[0103] φ (t,x) =φ (t-1，x) +△φ (t,t-1) +△φ x_r (15)

[0104] where, φ (t,x) is the full-field absolute phase value at time t, φ (t-l，x) is the full-field absolute phase value at time t - 1, △φ (t,t-1) is the phase change value of the reference point at adjacent sampling intervals after temporal phase unwrapping, and Δφ x_r is the magnitude of the full-field phase value relative to the reference point phase after spatial phase unwrapping.

[0105] Using the temporal phase change of the reference point as a line, connect the spatial phase values of the multi-step measurement field, ensuring the phase continuity of each measurement point in the full field. The selection of the reference point needs to first separate the high-frequency phase region that is difficult to capture and the normal distribution phase region according to the local spatial frequency of the phase distribution. After selecting the region of interest, find the point with the lowest phase change frequency as the reference point.

[0106] Figure 6A gradient change value graph generated by the deformation of the whole field and the whole process according to an embodiment of the present disclosure is shown.

[0107] Taking the central load of 50 μm as an example, the loading center is manually selected, that is, the point where the spatial gradient change is the smallest and the phase change frequency is the lowest, and the absolute phase change with respect to time is unfolded from this point. The spatial phases at different times are unwrapped starting from the absolute phase with respect to time at that moment, and the full-field unfolded phase diagram at different times is established. Through the calculations of equations (6) and (15), the phase information is accumulated to obtain the gradient change generated by the deformation of the whole field and the whole process.

[0108] Figure 7 A schematic diagram of a displacement reduction integration method according to an embodiment of the present disclosure is shown.

[0109] According to the shear speckle interference theory, if only overall rigid translation occurs on the surface of an object, the correlation of two interfering speckles will not form fringes. Therefore, this method is only sensitive to non-uniform motion on the surface of the object. Generally, when integrating the spatial gradient of the out-of-plane or in-plane displacement to obtain the relative displacement, the boundary conditions of the measured area need to be known. For example, it can be ensured that the boundary of the measured surface is fixed or the displacement of a certain point within the measured area is known, so as to establish the correct integration starting point. In this method, we establish a rectangular test piece model with fixed boundaries on all sides, and both the horizontal or vertical sides can be used as the integration starting point. The displacement value at the integration starting point is set to 0, and the integration path is along the shear direction. Such an integration method can directly and quickly obtain the out-of-plane deformation value on the entire surface without other algorithmic processing. Let be the displacement gradient field in the horizontal direction, be the starting point, and integrate along the horizontal direction. The integration method is as follows:

[0110]

[0111] In the application of the spatial carrier method, generally a large shear amount is used to ensure the separation of the spectra. However, the integration interval used in the integration formula is much smaller than the shear amount. At this time, the result obtained by using the direct integration method will deviate from the actual value. And using a network model of two-dimensional data for finite difference solution will be more suitable for the calculation of the large shear measurement results. The main idea of this model integration method is to construct a network model based on the relationship between each surface topography data point and the surrounding slope data points, and solve along the shear direction based on the finite difference method to obtain the deformation information. The relationship between the displacement change value of the point to be solved and the obtained displacement gradient is expressed as:

[0112]

[0113] Taking the shear amount as the interval and the shear direction as the x direction, the phase values are directly added in the way of equidistant summation. The calculation formula is as follows:

[0114]

[0115] Where m is the image row coordinate, n is the image column coordinate, and w (m,n) is the absolute displacement value of the current data point, and △w (m，n) represents the displacement change value of the current data point, and w (m,n-δ ) represents the displacement change value corresponding to the (m, n) coordinates on another misaligned image, δ represents the shear amount, and L represents the maximum coordinate of the fixed edge.

[0116] Figure 8 Shows an absolute out-of-plane deformation value map of an embodiment of the present disclosure.

[0117] Since the optical path shear direction is the x direction, the pixel points are accumulated row by row. At the starting part of the boundary, the phase difference of the non-overlapping area of the sheared image represents the absolute displacement change at the current position. After passing through the length of the shear amount, the images start to overlap, and the absolute displacement value of the current coordinate is the sum of the relative displacement value of the current coordinate and the relative displacement value of the corresponding coordinate in another image. The calculation end point is the overlapping image boundary point. Calculate row by row in this way, and finally obtain the absolute out-of-plane deformation value of the whole field.

[0118] Figure 9 Shows a block diagram of a wide-range and high-resolution deformation measurement device according to an embodiment of the present disclosure. As Figure 9 shown, a wide-range and high-resolution deformation measurement device according to an embodiment of the present disclosure includes:

[0119] A building module 600 for building a dual-wavelength spatial carrier digital shear speckle interferometry measurement optical path;

[0120] A first determination module 601 for determining the phase distribution of the out-of-plane deformation gradient;

[0121] A second determination module 602 for determining the absolute phase change of the out-of-plane deformation gradient;

[0122] A third determination module 603 for determining the gradient change generated by the deformation of the whole field and the whole process;

[0123] A fourth determination module 604 for determining the out-of-plane deformation of the whole field.

[0124] The building module 600 is specifically used for:

[0125] Building a dual-wavelength spatial carrier digital shear speckle interferometry measurement optical path, and the dual-wavelength spatial carrier digital shear speckle interferometry measurement optical path includes a diaphragm, a shear module, an imaging lens, an image sensor, and two lasers with different wavelengths;

[0126] ​The lasers with two different wavelengths output laser light that irradiates the surface of the object to be measured at the same time at a symmetric angle, and their diffuse reflection light passes through the diaphragm, imaging lens, Michelson shear module respectively, and is finally received by the image sensor;

[0127] The shear module is used to determine the shear direction, introduce the shear amount and introduce the spatial carrier amount, wherein the spatial carrier amount and the two different laser wavelengths jointly determine the distribution of the interference spectrum.

[0128] The first determination module 601 is specifically configured to:

[0129] According to the shear module in the double-wavelength spatial carrier digital shear speckle interferometry optical path, perform double-

[0130] Figure 9 The block diagram of a wide-range and high-resolution deformation measurement device according to an embodiment of the present disclosure is shown. As Figure 9 shown, a wide-range and high-resolution deformation measurement device according to an embodiment of the present disclosure includes:

[0131] A building module 600, configured to build a double-wavelength spatial carrier digital shear speckle interferometry optical path;

[0132] A first determination module 601, configured to determine the phase distribution of the out-of-plane deformation gradient;

[0133] A second determination module 602, configured to determine the absolute phase change of the out-of-plane deformation gradient;

[0134] A third determination module 603, configured to determine the gradient change generated by the full-field and whole-process deformation;

[0135] A fourth determination module 604, configured to determine the full-field out-of-plane deformation.

[0136] The building module 600 is specifically configured to:

[0137] Build a double-wavelength spatial carrier digital shear speckle interferometry optical path, and the double-wavelength spatial carrier digital shear speckle interferometry optical path includes a diaphragm, a shear module, an imaging lens, an image sensor, and two lasers with different wavelengths;

[0138] The lasers with two different wavelengths output laser light that irradiates the surface of the object to be measured at the same time at a symmetric angle, and their diffuse reflection light passes through the diaphragm, imaging lens, Michelson shear module respectively, and is finally received by the image sensor;

[0139] The shear module is used to determine the shear direction, introduce the shear amount and introduce the spatial carrier amount, wherein the spatial carrier amount and the two different laser wavelengths jointly determine the distribution of the interference spectrum.

[0140] The first determination module 601 is specifically configured to:

[0141] According to the shearing module in the double-wavelength spatial carrier digital shearography optical path, perform spectral separation of each double-wavelength optical path, and determine the out-of-plane deformation phase distribution of each through frequency-domain extraction.

[0142] The second determination module 602 is specifically configured to:

[0143] Apply the spatio-temporal phase unwrapping algorithm to process the wrapped phase map and determine the absolute phase change of the out-of-plane deformation gradient.

[0144] The third determination module 603 is specifically configured to:

[0145] Accumulate the absolute phase change information to determine the gradient change generated by the full-field and whole-process deformation.

[0146] The fourth determination module 604 is specifically configured to:

[0147] Determine the boundary conditions and integration conditions of the full-field deformation gradient change, and perform finite difference solution on the gradient change generated by the full-field and whole-process deformation along the integration direction using a network model of two-dimensional data to determine the full-field out-of-plane deformation information.

[0148] In some embodiments, the functions or modules included in the device provided in the embodiments of the present disclosure can be used to execute the methods described in the above method embodiments. The specific implementation can refer to the description of the above method embodiments. For the sake of brevity, it will not be repeated here.

[0149] The embodiments of the present disclosure also propose a computer-readable storage medium, on which computer program instructions are stored, and when the computer program instructions are executed by a processor, the above methods are implemented. The computer-readable storage medium can be a volatile or non-volatile computer-readable storage medium.

[0150] The embodiments of the present disclosure also propose an electronic device, including: a processor; a memory for storing instructions executable by the processor; wherein, the processor is configured to implement the above methods when executing the instructions stored in the memory.

[0151] The embodiments of the present disclosure also provide a computer program product, including computer-readable code, or a non-volatile computer-readable storage medium carrying the computer-readable code. When the computer-readable code runs in the processor of the electronic device, the processor in the electronic device executes the above methods.

[0152] The embodiments of the present disclosure have been described above. The above description is exemplary and not exhaustive, and is also not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A wide-range and high-resolution deformation measurement method, characterized in that Comprising: Construct a dual-wavelength spatial carrier digital shearography measurement optical path; Determine the phase distribution of the out-of-plane deformation gradient according to the dual-wavelength spatial carrier digital shearography measurement optical path; Determine the absolute phase change of the out-of-plane deformation gradient according to the phase distribution of the out-of-plane deformation gradient; Determine the gradient change generated by the full-field and full-process deformation according to the absolute phase change of the out-of-plane deformation gradient; Determine the full-field out-of-plane deformation according to the gradient change generated by the full-field and full-process deformation; 2. The method according to claim 1, wherein The dual-wavelength spatial carrier digital shearography measurement optical path includes two lasers with different wavelengths, an aperture, an imaging lens, and a shearing device; For the two lasers with different wavelengths, the output laser irradiates the surface of the object to be measured at the same time at a symmetric angle, and the diffuse reflected light passes through the aperture, the imaging lens, the shearing module respectively, and is finally received by the image sensor; The shearing module is used to determine the shearing direction, introduce the shearing amount and introduce the spatial carrier amount, wherein the spatial carrier amount and the two different laser wavelengths jointly determine the distribution of the interference spectrum.

3. The method according to claim 1 or 2, characterized in that The dual-wavelength spatial carrier digital shearography measurement optical path uses lasers with different wavelengths as light sources, the illumination angles of the two-way lasers are equal and symmetrically placed, and the phase distribution of the out-of-plane deformation gradient is extracted in the frequency domain respectively.

4. The method according to claim 1, wherein Determine the absolute phase change of the out-of-plane deformation gradient according to the phase distribution of the out-of-plane deformation gradient, including: Perform spatio-temporal unwrapping processing on all phase difference map information during the acquisition process; The spatio-temporal unwrapping processing restores the absolute phase change of the out-of-plane deformation gradient from the perspective of the combination of one-dimensional time and two-dimensional spatial phase difference information.

5. The method according to claim 4, characterized in that Determine the absolute phase change value of the deformation gradient of the surface to be measured according to the spatio-temporal unwrapping algorithm, including: Perform time unwrapping on the wrapped phase diagram to determine the phase change of the selected reference point on the time axis; Perform spatial unwrapping on the wrapped phase diagram to determine the spatial phase difference value of each sampling interval; Determine the absolute phase change of the full-field deformation according to the phase change of the reference point on the time axis and the spatial phase difference value within each sampling interval.

6. The method according to claim 5, wherein Determine the absolute phase change of the full-field deformation according to the phase change of the reference point on the time axis and the spatial phase difference value of each sampling interval, including: Determine the spatial phase change value with time information according to the phase change of the selected reference point on the time axis and the spatial phase difference value of each sampling interval; Determine the absolute phase change of the deformation according to the spatial phase change value with time information.

7. The method according to claim 1, characterized in that, Determine the gradient change generated by the full-field and full-process deformation according to the absolute phase change of the out-of-plane deformation gradient, including: After selecting the region of interest, find the point with the lowest phase change frequency as the reference point and determine the absolute phase change in time; Unwrap the spatial phase at different times starting from the absolute phase in time at that moment to determine the full-field unwrapped phase diagram at different times; Determine the gradient change generated by the full-field and full-process deformation according to the full-field unwrapped phase diagram at different times.

8. The method according to claim 1, wherein Determine the full-field out-of-plane deformation according to the gradient change generated by the full-field and full-process deformation, including: Establish a rectangular test piece model fixed around, and determine the boundary conditions for the integral of the displacement space gradient around the rectangle; Both the horizontal or vertical sides of the rectangular test piece can be used as the integral starting point, and the displacement value of the integral starting point is set to 0, and the integral path is along the shear direction.

9. The method according to claim 8, wherein, Use a network model of two-dimensional data for finite difference solution to calculate the large shear measurement results, including: According to the two-dimensional network model, determine the network model based on the relationship between each surface topography data point and the surrounding slope data points; According to the finite difference method, solve along the shear direction to determine the out-of-plane deformation information.

10. A deformation measurement device for wide-range and high-resolution, characterized in that, Including: A building module for building an optical path for double-wavelength spatial carrier digital shearography measurement; A first determination module for determining the phase distribution of the out-of-plane deformation gradient; A second determination module for determining the absolute phase change of the out-of-plane deformation gradient; A third determination module for determining the gradient change generated by the full-field and whole-process deformation; A fourth determination module for determining the full-field out-of-plane deformation.

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