Multi-directional synchronous measurement system and method based on laser shear speckle interferometry

Abstract

This invention provides a multi-directional synchronous measurement system and method based on laser shear speckle interferometry, relating to the field of shear speckle interferometry technology. The system includes a laser, a beam splitter, and an imaging device. The laser beam generated by the laser illuminates the object under test, forming diffuse reflection light. Part of the diffuse reflection light passes sequentially through an imaging objective lens and a Fourier lens, then illuminates the beam splitter, which separates it into transmitted and reflected light. Part of the reflected light is reflected by a mirror and then sequentially passes through an aperture stop, the beam splitter, and a Fourier lens. By separating the mirrors (mirror 1, 2, and 3), aperture stops 1, 2, and 3) into independent modules for individual adjustment, the laser shear speckle technology achieves separation of shearing amount and aperture stop adjustment, thereby ensuring measurement effectiveness. Based on this, combined with a pulsed laser and a gated imaging device, transient or dynamic measurements are achieved, improving measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of shear speckle interferometry, specifically to a multi-directional synchronous measurement system and method based on laser shear speckle interferometry. Background Technology

[0002] Laser speckle interferometry uses coherent light to illuminate the target under test. After scattering by the surface microstructure, an interference speckle field is formed. By using a series of laser speckle fields, the minute displacement or deformation of the target under test can be obtained. It has the advantages of being non-contact, having a large field of view, and being highly sensitive, and has wide applications in materials mechanics, non-destructive testing, and biomedicine.

[0003] Laser speckle interferometry is broadly classified into two categories: reference light interferometry and shearing interferometry. Shearing interferometry-based laser speckle interferometry, defined as laser shearing speckle interferometry, offers advantages such as resistance to environmental interference and a large measurement range. Space-carrier laser shearing speckle interferometry utilizes a single-frame laser speckle image, processing it in the frequency domain (e.g., filtering) to extract phase information, thereby obtaining information related to object deformation and providing dynamic measurement capabilities. Traditional space-carrier laser shearing speckle interferometry primarily introduces a larger carrier wave in the optical path by adjusting the shearing amount and adding an aperture, ensuring the separation of the 0th and 1st order speckle frequencies in the frequency domain. The adjustment of the shearing amount and the aperture directly affects the measurement results.

[0004] However, current space carrier laser shear speckle interferometry cannot independently adjust the shearing amount and aperture stop, which easily leads to poor shear speckle interferometry measurement results, especially in transient or dynamic detection scenarios. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a multi-directional synchronous measurement system and method based on laser shear speckle interferometry. This solves the technical problem that the shearing amount and aperture stop cannot be independently adjusted during the current shear speckle interferometry process. On this basis, a pulsed laser and a gated imaging device are used to achieve transient or dynamic detection while improving measurement accuracy.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] In a first aspect, the present invention provides a multi-directional synchronous measurement system based on laser shear speckle interferometry, comprising: a laser, a beam splitter, and an imaging device;

[0010] The laser beam generated by the laser illuminates the object under test, forming diffuse reflected light.

[0011] Part of the diffuse reflection light passes through the imaging objective and the Fourier lens in sequence and then shines on the beam splitter prism, where it is split into transmitted light and reflected light.

[0012] After being reflected by mirror one, part of the reflected light passes through aperture stop one, beam splitter prism and Fourier lens two in sequence before illuminating the imaging surface of the imaging device.

[0013] Part of the transmitted light is reflected by the second mirror, then passes through the second aperture stop, is reflected by the beam splitter, passes through the second Fourier lens, and illuminates the imaging surface of the imaging device.

[0014] Part of the transmitted light is reflected by the third mirror, then passes through the third aperture stop, is reflected by the beam splitter, passes through the second Fourier lens, and illuminates the imaging surface of the imaging device.

[0015] The Fourier lens one and Fourier lens two constitute a 4f system, and the surface of the object being measured is located on the front focal plane of the Fourier lens one, while the imaging plane of the imaging device is located on the rear focal plane of the Fourier lens two.

[0016] The three reflectors are all located on the spectral plane of the 4f system.

[0017] Preferably, the laser shearing speckle interferometer system also includes a laser beam expander;

[0018] The laser beam expander is located between the laser and the object under test, and is used to expand the diameter of the laser beam while maintaining the collimation of the laser beam as it irradiates the object under test.

[0019] Preferably, reflector one is driven by electroceramic one, reflector two is driven by electroceramic two, and reflector three is driven by electroceramic three.

[0020] Preferably, the beam splitter performs beam splitting at a 1:1 ratio.

[0021] Preferably, the imaging objective lens adopts an image-side telecentric design, and the 4f system adopts a double telecentric design.

[0022] Preferably, the laser is one of a continuous laser, a pulsed laser, or a quasi-continuous laser;

[0023] The imaging device is one of CCD, CMOS, photoelectric imaging device array, or gated imaging device;

[0024] Among them, gated imaging devices and pulsed lasers enable transient or dynamic detection of the object under test.

[0025] Secondly, the present invention provides a multi-directional synchronous measurement method based on laser shear speckle interferometry, comprising the following steps:

[0026] The laser beam emitted from the laser is expanded in diameter by a laser beam expander and collimated before illuminating the object under test to form diffuse reflected light.

[0027] Part of the diffuse reflection light passes through the imaging objective and the Fourier lens in sequence and then shines on the beam splitter prism, where it is split into transmitted light and reflected light.

[0028] After being reflected by mirror one, part of the reflected light passes through aperture stop one, beam splitter prism and Fourier lens in sequence, and shines on the imaging surface of the imaging device as beam A, forming the first light field distribution.

[0029] Part of the transmitted light is reflected by the second mirror, then passes through the second aperture stop, is reflected by the beam splitter, and passes through the second Fourier lens, becoming beam B that illuminates the imaging surface of the imaging device, forming a second light field distribution.

[0030] Part of the transmitted light is reflected by the third mirror, then passes through the third aperture stop, is reflected by the beam splitter, passes through the second Fourier lens, and shines as beam C onto the imaging surface of the imaging device, forming the third light field distribution.

[0031] Using the position of the first light field distribution formed by beam A as a reference, adjust mirror two to shift beam B in the x direction, and adjust mirror three to shift beam C in the y direction;

[0032] After adjusting mirrors two and three, beam A and beam B are superimposed to achieve shear speckle interference in the x-direction, beam A and beam C are superimposed to achieve shear speckle interference in the y-direction, and beam B and beam C are superimposed to achieve shear speckle interference in the oblique direction.

[0033] Preferably, in shear speckle interference, when adjusting mirror one, mirror two, and mirror three, the rotation axes of mirror one, mirror two, and mirror three are all located on the central axis of the focal plane of the 4f system, and mirror one, mirror two, and mirror three are all located on the spectral plane of the 4f system.

[0034] (III) Beneficial Effects

[0035] This invention provides a multi-directional synchronous measurement system and method based on laser shear speckle interferometry. Compared with existing technologies, it has the following advantages:

[0036] By separating the reflector one, reflector two, reflector three, aperture stop one, aperture stop two, and aperture stop three into independent modules for individual adjustment, laser shearing speckle technology that separates shearing amount from aperture stop adjustment is achieved, thereby ensuring measurement results.

[0037] Employing pulsed lasers and gated imaging devices, this method enables time-resolved measurements during speckle interferometry, allowing for transient or dynamic measurements and improving measurement accuracy. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of a laser shearing speckle interferometry system for multi-directional synchronous measurement according to an embodiment of the present invention;

[0040] Figure 2 for Figure 1 A schematic diagram showing the positions of aperture stop one, aperture stop two, and aperture stop three;

[0041] Figure 3 This is a schematic diagram showing the positions of aperture stop 1, aperture stop 2, and aperture stop 3 when they are mapped onto the same exit pupil plane;

[0042] Figure 4 This is a schematic diagram of the spectrum after Fourier transform;

[0043] Figure 5 This is a schematic diagram of the ideal spectrum after Fourier transform.

[0044] Figure labels: 1. Laser; 2. Laser beam expander; 3. Object under test; 4. Imaging objective lens; 5. Fourier lens one; 6. Beam splitter prism; 7. Mirror one; 8. Mirror two; 9. Mirror three; 10. Fourier lens two; 11. Imaging device;

[0045] 70. Aperture stop one; 80. Aperture stop two; 90. Aperture stop three. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] This application provides a multi-directional synchronous measurement system and method based on laser shear speckle interferometry, which solves the technical problem that the shearing amount and aperture stop cannot be independently adjusted in the current shear speckle interferometry process, and improves the measurement effect of shear speckle interferometry.

[0048] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0049] This invention provides a multi-directional synchronous measurement laser shear speckle interferometry system, comprising: a laser 1, a beam splitter 6, and an imaging device 11;

[0050] The laser beam generated by the laser 1 illuminates the object under test 3 to form diffuse reflected light.

[0051] Part of the diffuse reflected light passes through the imaging objective lens 4 and the Fourier lens 5 in sequence and illuminates the beam splitter prism 6, where it is split into transmitted light and reflected light.

[0052] After being reflected by mirror 7, part of the reflected light passes through aperture stop 70, beam splitter 6, and Fourier lens 10 in sequence before illuminating the imaging surface of imaging device 11.

[0053] Part of the transmitted light is reflected by mirror 28, then passes through aperture stop 280, is reflected by beam splitter 6, passes through Fourier lens 210, and illuminates the imaging surface of imaging device 11.

[0054] Part of the transmitted light is reflected by mirror 39, then passes through aperture stop 390, is reflected by beam splitter 6, passes through Fourier lens 210, and illuminates the imaging surface of imaging device 11.

[0055] The Fourier lens 5 and the Fourier lens 10 constitute a 4f system, and the surface of the object under test 3 is located on the front focal plane of the Fourier lens 5, while the imaging surface of the imaging device 11 is located on the rear focal plane of the Fourier lens 10.

[0056] The reflector 7, reflector 8, and reflector 9 are all located on the spectral plane of the 4f system.

[0057] Specifically, the laser 1 is one of a continuous laser, a pulsed laser, or a quasi-continuous laser;

[0058] Imaging device 11 is one of CCD, CMOS, photoelectric imaging device array or gated imaging device;

[0059] Among them, gated imaging devices and pulsed lasers enable transient or dynamic detection of the object under test 3;

[0060] Beam splitter 6 performs beam splitting at a 1:1 ratio;

[0061] It should be noted that the imaging objective 4 uses a telecentric image-side design, with the exit pupil at infinity; the 4f system uses a double telecentric design, with the entrance pupil at infinity.

[0062] With the 4f system unchanged, focusing can be achieved by independently adjusting the lens of imaging objective 4, thereby flexibly changing the measurement distance; different image-side telecentric imaging lenses with different focal lengths can also be replaced to obtain different imaging magnifications. The laser shearing speckle interferometry system is modularly designed, which facilitates the control of the speckle interferometry system.

[0063] Among them, reflector 7 is driven by electro-ceramic 1, reflector 8 is driven by electro-ceramic 2, and reflector 9 is driven by electro-ceramic 3. By controlling the adjustment of reflector 7, reflector 8 and reflector 9, the shearing amount and shearing direction can be dynamically adjusted.

[0064] Meanwhile, aperture stop 70, aperture stop 80 and aperture stop 90 can all be adjusted independently to achieve space carrier adjustment;

[0065] Specifically, the independent adjustment of aperture stop 70, aperture stop 80 and aperture stop 90 refers to controlling the carrier frequency by constraining the relative positions of the three aperture stops mapped onto the same plane and the size of the aperture stops during structural design; in actual use, the aperture stops are attached to the corresponding reflectors, and the rotation of the corresponding aperture stops is driven by adjusting the rotation of the reflectors.

[0066] By separating the reflector 7, reflector 8, reflector 9, aperture stop 70, aperture stop 80, and aperture stop 90 into independent modules for individual adjustment, laser shearing speckle technology that separates shearing amount from aperture stop adjustment is achieved, thereby ensuring measurement results.

[0067] Specifically, the system also includes a laser beam expander 2;

[0068] The laser beam expander 2 is located between the laser and the object under test, and is used to expand the diameter of the laser beam while maintaining the collimation of the laser beam as it irradiates the object under test.

[0069] like Figures 1-5 As shown, a multi-directional synchronous measurement method based on laser shear speckle interferometry is used to perform interferometric measurements, including the following steps:

[0070] The laser beam emitted from laser 1 is expanded in diameter by laser beam expander 2 and collimated before illuminating the object under test 3 to form diffuse reflection light.

[0071] Part of the diffuse reflected light passes through the imaging objective lens 4 and the Fourier lens 5 in sequence and illuminates the beam splitter prism 6, where it is split into transmitted light and reflected light.

[0072] After being reflected by mirror 7, part of the reflected light passes through aperture stop 70, beam splitter 6, and Fourier lens 10 in sequence, and shines as beam A onto the imaging surface of imaging device 11 to form the first light field distribution.

[0073] Part of the transmitted light is reflected by mirror 8, then passes through aperture stop 80, is reflected by beam splitter 6, passes through Fourier lens 10, and shines as beam B onto the imaging surface of imaging device 11, forming a second light field distribution.

[0074] Part of the transmitted light is reflected by the mirror 39, then passes through the aperture stop 390, is reflected by the beam splitter 6, passes through the Fourier lens 210, and shines as beam C onto the imaging surface of the imaging device 11, forming the third light field distribution.

[0075] Using the position of the first light field distribution formed by beam A as a reference, adjust mirror 8 to shift beam B in the x direction, and adjust mirror 9 to shift beam C in the y direction.

[0076] After adjusting reflectors 8 and 9, beam A and beam B are superimposed to achieve shear speckle interference in the x-direction, beam A and beam C are superimposed to achieve shear speckle interference in the y-direction, and beam B and beam C are superimposed to achieve shear speckle interference in the oblique direction.

[0077] This application employs a multi-directional synchronous measurement method based on laser shearing speckle interferometry to perform speckle interferometry. The second reflector 8 is adjusted to cause the second light field distribution to undergo shearing in the positive X direction relative to the first light field distribution; the third reflector 9 is adjusted to cause the third light field distribution to undergo shearing in the positive Y direction relative to the first light field distribution; and the third light field distribution undergoes shearing in an oblique direction relative to the second light field distribution, specifically as follows... Figure 3 As shown;

[0078] It should be noted that shearing refers to the misalignment between images; by utilizing the first, second, and third light field distributions to interfere with each other on the target surface of the imaging device 11, a multi-directional shearing speckle interferogram is obtained.

[0079] The following is a detailed explanation of each step:

[0080] When aperture stops 70, 80, and 90 are translated in the pupil plane, the complex amplitude distribution in the spatial domain will be introduced into a phase shift, while in the frequency domain it will cause a translation of the spectrum on the spectral plane.

[0081] When adjusting the shearing amount in sheared speckle interference, the rotation axes of mirror 7, mirror 8 and mirror 9 are all located on the central axis of the focal plane of the 4f system, and mirror 7, mirror 8 and mirror 9 are all located on the spectral plane of the 4f system, thus ensuring that the sheared optical path does not introduce additional optical path difference.

[0082] In the three-beam optical path of the 4f system, mirror 7, mirror 8, and mirror 9 are all located on the spectral plane of the 4f system. By laterally misaligning them, the principal rays of the three beams interfering on the image plane have a certain angle, thus realizing a spatial carrier. No matter how the shearing amount is adjusted, the angle between the principal rays of the three beams remains unchanged. Therefore, adjusting the shearing amount does not cause a change in the spatial carrier. By adjusting the spatial carrier through aperture stop 70, aperture stop 80, and aperture stop 90, the shearing amount and the spatial carrier can be adjusted separately, which helps to improve the measurement effect of shear speckle interferometry.

[0083] Although the aperture stops in beams A, B, and C are located on opposite sides of beam splitter 6, by mapping the three aperture stops onto the same exit pupil plane (the exit pupil is the exit point of the beam that can participate in imaging at each point on the object surface when it leaves the system), the positional relationship of aperture stops 70, 80, and 90 can be adjusted as follows. Figure 2 As shown, at this time, the spatial coordinate center on the imaging surface of the imaging device 11 is located on the optical axis where the beam A is located, and the optical axis intersects the mapped exit pupil plane perpendicularly at its center.

[0084] The working principle of a multi-directional synchronous measurement laser shear speckle interferometry provided in this embodiment is as follows:

[0085] Assume the wavefront of beam A is u0(x,y), and the shear wavefront of beam B in the x-direction is u. x (x,y), the shear wavefront of beam C in the y-direction is u y Given (x, y), the wavefronts of the three light paths and two wavelengths can be expressed by the following equation:

[0086]

[0087] In the formula, (x,y) represents the spatial coordinates on the imaging surface of the imaging device 11 (the center of this coordinate system is located on the optical axis), i is the imaginary unit, A0 is the wavefront intensity amplitude, δx and δy are the shearing amounts caused by adjusting the angles of mirror 8 and mirror 9, respectively, φ(x,y) is the phase including speckle noise, and C x C y The spatial carrier introduced for aperture stop offset can be specifically represented as:

[0088]

[0089] Where λ is the laser wavelength, d is the distance between the centers of the aperture stop of beams B and C relative to beam A, and f is the focal length of the Fourier transform lens.

[0090] After the three beams are superimposed on the CCD target surface, the intensity of the interferogram is as follows: Figure 4 As shown:

[0091] Where * denotes complex conjugate, to extract the phase, a Fourier transform is performed on the speckle interferogram, transforming it from the spatial domain to the Fourier domain, resulting in:

[0092]

[0093] in This represents the convolution operation;

[0094] Fourier spectrum diagram as shown Figure 4 As shown;

[0095] Among them, the central low-frequency term Includes background information and spectrum. It contains phase information of shear speckle interference;

[0096] By using the mutual misalignment of the aperture stops of the spectral surfaces of beams A, B, and C, a constant carrier frequency is obtained, enabling the spectrum containing various types of information to be completely separated in the Fourier domain.

[0097] During the design process, the size of the aperture stop and its relative position determine whether the various spectra can be completely separated in the Fourier domain;

[0098] In an imaging system, an aperture stop can limit the size of the imaging beam, which in the spatial domain manifests as selecting the beam, and in the frequency domain manifests as selecting the spatial frequency of the light.

[0099] In the system, the aperture stop acts as a spatial frequency filter, limiting the maximum spatial frequency that can be captured, with a cutoff spatial frequency f. c The relationship with the aperture stop diameter D is as follows:

[0100]

[0101] From formula (2), the spatial frequency shift f0 introduced by the relative spatial position relationship of the aperture stop is:

[0102]

[0103] Where λ is the laser wavelength, d is the relative position of beams B and C with respect to the center of the aperture of beam A, and f is the focal length of the Fourier transform lens.

[0104] The ideal spectrum after Fourier transform is as follows: Figure 5 As shown;

[0105] Depend on Figure 5 It can be seen that in order to completely separate these spectral spatial frequency offsets f0, at least the cutoff frequency f is required. c twice that, therefore we have:

[0106] 2f c ≤f0 (7)

[0107] Combining formulas (5) and (6), the relationship between the aperture stop size D and the relative position d of the aperture stop during spectral separation is as follows:

[0108] 2D≤d (8)

[0109] Example: The following example, with the shearing direction as x, illustrates the principle of extracting phase from a single-frame interferogram. The extraction algorithms for other phase maps are the same, as detailed below;

[0110] In the spectrum, a bandpass filter (BPF) with an appropriate cutoff frequency is selected and combined with inverse Fourier transform to extract... Its mathematical model is expressed as:

[0111]

[0112] Therefore, the phase can be calculated using the following formula:

[0113]

[0114] Where Im and Re represent the imaginary and real parts of the complex number, respectively;

[0115] The phase distribution of an object after deformation can be calculated using the same method: subtract the phases before and after deformation. The relative phase change Δφ then depends only on the first derivative component of the deformation along the x-direction, expressed as:

[0116]

[0117] In summary, compared with existing technologies, it has the following beneficial effects:

[0118] 1. By separating the reflector 7, reflector 8, reflector 9, aperture stop 70, aperture stop 80, and aperture stop 90 into independent modules for individual adjustment, laser shearing speckle technology that separates shearing amount from aperture stop adjustment is achieved, thereby ensuring measurement results.

[0119] 2. This application uses the laser shearing speckle interferometry method for interferometric measurement. The second reflector 8 is adjusted to cause the second light field distribution to be sheared in the positive X direction relative to the first light field distribution; the third reflector 9 is adjusted to cause the third light field distribution to be sheared in the positive Y direction relative to the first light field distribution; and the third light field distribution is sheared obliquely relative to the second light field distribution, thereby obtaining a multi-directional shearing speckle interferogram and realizing multi-directional synchronous measurement of speckle interferometry.

[0120] 3. When adjusting the shearing amount in shear speckle interference, the rotation axes of mirror 7, mirror 8, and mirror 9 are all located on the central axis of the focal plane of the 4f system, and mirror 7, mirror 8, and mirror 9 are all located on the spectral plane of the 4f system, thus ensuring that the sheared optical path does not introduce additional optical path difference.

[0121] 4. In the three-beam optical path of the 4f system, reflectors 7, 8, and 9 are all located on the spectral plane of the 4f system. By laterally misaligning them, the principal rays of the three beams interfering on the image plane have a certain angle, thus realizing a spatial carrier. No matter how the shearing amount is adjusted, the angle between the principal rays of the three beams remains unchanged. Therefore, adjusting the shearing amount does not cause a change in the spatial carrier. By adjusting the spatial carrier through aperture stops 70, 80, and 90, the shearing amount and the spatial carrier can be separated and adjusted, which helps to improve the measurement effect of sheared speckle interferometry.

[0122] 5. The laser shearing speckle interferometry system of the present invention uses a pulsed laser and a gated imaging device, which has time-resolved measurement capability during speckle interferometry measurement, realizes transient or dynamic measurement, and improves measurement accuracy.

[0123] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0124] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-directional synchronous measurement system based on laser shear speckle interferometry, characterized in that, include: Lasers, beam splitters, and imaging devices; The laser beam generated by the laser illuminates the object under test, forming diffuse reflected light. Part of the diffuse reflection light passes through the imaging objective and the Fourier lens in sequence and then shines on the beam splitter prism, where it is split into transmitted light and reflected light. After being reflected by mirror one, part of the reflected light passes through aperture stop one, beam splitter prism and Fourier lens two in sequence before illuminating the imaging surface of the imaging device. Part of the transmitted light is reflected by the second mirror, then passes through the second aperture stop, is reflected by the beam splitter, passes through the second Fourier lens, and illuminates the imaging surface of the imaging device. Part of the transmitted light is reflected by the third mirror, then passes through the third aperture stop, is reflected by the beam splitter, passes through the second Fourier lens, and illuminates the imaging surface of the imaging device. The Fourier lens one and Fourier lens two constitute a 4f system, and the surface of the object being measured is located on the front focal plane of the Fourier lens one, while the imaging plane of the imaging device is located on the rear focal plane of the Fourier lens two. The first, second and third reflectors are all located on the spectral plane of the 4f system; The first reflector is driven by the first electroceramic, the second reflector by the second electroceramic, and the third reflector by the third electroceramic, so that the first, second and third reflectors can be dynamically adjusted respectively.

2. The multi-directional synchronous measurement system based on laser shear speckle interferometry as described in claim 1, characterized in that, It also includes laser beam expanders; The laser beam expander is located between the laser and the object under test, and is used to expand the diameter of the laser beam while maintaining the collimation of the laser beam as it irradiates the object under test.

3. The multi-directional synchronous measurement system based on laser shear speckle interferometry as described in claim 1, characterized in that, The beam splitter performs beam splitting at a 1:1 ratio.

4. The multi-directional synchronous measurement system based on laser shear speckle interferometry as described in claim 1, characterized in that, The imaging objective lens adopts an image-side telecentric design, and the 4f system adopts a double telecentric design.

5. A multi-directional synchronous measurement system based on laser shear speckle interferometry as described in claim 1, characterized in that, The laser is one of a continuous laser, a pulsed laser, or a quasi-continuous laser; The imaging device is one of CCD, CMOS, photoelectric imaging device array, or gated imaging device; Among them, gated imaging devices and pulsed lasers enable transient or dynamic detection of the object under test.

6. A multi-directional synchronous measurement method based on laser shear speckle interferometry, characterized in that, Interference measurement using the multi-directional synchronous measurement system for laser shear speckle interferometry as described in any one of claims 1-5 includes the following steps: The laser beam emitted from the laser is expanded in diameter by a laser beam expander and collimated before illuminating the object under test to form diffuse reflected light. Part of the diffuse reflection light passes through the imaging objective and the Fourier lens in sequence and then shines on the beam splitter prism, where it is split into transmitted light and reflected light. After being reflected by mirror one, part of the reflected light passes through aperture stop one, beam splitter prism and Fourier lens two in sequence, and then shines as beam A onto the imaging surface of the imaging device, forming the first light field distribution. Part of the transmitted light is reflected by the second mirror, then passes through the second aperture stop, is reflected by the beam splitter, and passes through the second Fourier lens, becoming beam B that illuminates the imaging surface of the imaging device, forming a second light field distribution. Part of the transmitted light is reflected by the third mirror, then passes through the third aperture stop, is reflected by the beam splitter, passes through the second Fourier lens, and shines as beam C onto the imaging surface of the imaging device, forming the third light field distribution. Using the position of the first light field distribution formed by beam A as a reference, adjust mirror two so that beam B is in... Direction shift, adjust the three reflectors to make beam C in Direction shift; After adjusting mirrors two and three, beam A and beam B are superimposed. Directional shear speckle interference is achieved by superimposing beams A and C. Oblique shear speckle interference is achieved by superimposing beams B and C.

7. The multi-directional synchronous measurement method based on laser shear speckle interferometry as described in claim 6, characterized in that, In shear speckle interference, when adjusting mirror one, mirror two, and mirror three, the rotation axes of mirror one, mirror two, and mirror three are all located on the central axis of the focal plane of the 4f system, and mirror one, mirror two, and mirror three are all located on the spectral plane of the 4f system.

Images