Laser shearing speckle interference measuring device and use method thereof

Abstract

The invention discloses a laser shearing speckle interference measuring device, which is used for solving the problem of insufficient capability of detecting internal defects of an existing composite material. The device comprises an illumination imaging module, a shearing interference detection module and a control acquisition processing module. The illumination imaging module comprises a laser, a beam expander, an illumination detection beam combiner and an imaging assembly; the illumination detection beam combiner is composed of a light passing area and a reflection area. The radius of the light passing area is not smaller than the radius of the circumcircle of the image surface of the imaging assembly. The illumination detection beam combiner is installed at the image plane position of the imaging assembly. An illumination light beam emitted by the laser is expanded by the beam expander, is reflected by a reflection area of the illumination detection beam combiner, and is irradiated to a to-be-detected piece through the imaging assembly; the illumination light beam is reflected by the to-be-detected piece to form a detection light beam, and the detection light beam is imaged by the imaging assembly and then enters the shearing interference detection module through a light passing area of the illumination detection beam combiner. The detection capability of the internal defects of the composite material can be effectively improved.

Description

Technical Field

[0001] The invention relates to a laser shearing speckle interferometry measurement device and a use method thereof, belonging to the technical field of laser speckle interferometry measurement. Background Art

[0002] Aviation composite materials have excellent mechanical and physical properties and are widely used in various types of aircraft. Detecting and identifying internal defects of composite materials during manufacturing and use can improve manufacturing processes, product quality and safety. Internal defects of composite materials mainly include laminate delamination, debonding, cracks, bubbles, inclusions, erosion, improper curing, core material deformation, matrix cracking and other defects as well as impact damage. The technologies used to detect internal defects of composite materials mainly include ultrasonic, microwave, X-ray, optical and other detection technologies.

[0003] As an optical detection technology, the basic principle of laser shearing speckle interferometry is to record and compare the laser speckle information of composite materials before and after loading under the conditions of heat, vacuum, force, etc., and obtain the local abnormal deformation induced by defects through data processing and analysis, so as to identify and determine the internal defects of composite materials. Since laser shearing speckle interferometry adopts a self-reference optical path, its measurement result is the first-order derivative of displacement, so it is insensitive to the rigid body motion of the object and has strong anti-interference ability. It has been used in various internal defect detection tests of aviation composite materials.

[0004] Laser shear speckle interferometry systems can be divided into time phase shift laser shear speckle interferometry systems and space carrier laser shear speckle interferometry systems according to the measurement timeliness. Among them, the time phase shift laser shear speckle interferometry system uses phase shift devices such as PZT to obtain multiple frames of shear speckle interferometry before and after the material displacement step by step according to the order of acquisition time, and extracts the phase by time phase shift method. It is a static and quasi-dynamic measurement with a large measurement dynamic range. In the existing time phase shift laser shear speckle interferometry measurement system, paraxial illumination detection, time phase shift and fixed shear amount are mainly used to carry out material internal defect detection. A few technical solutions using coaxial illumination detection use a dichroic prism to adjust the laser illumination path. When non-destructively testing internal defects of composite materials, heat, vacuum, force and other excitation methods are mainly used. On the one hand, the deformation of internal defects with deeper and smaller size is smaller under external excitation. On the other hand, there are stray light, environmental interference and other factors that affect the defect detection capability. The laser shear speckle interferometry system in the prior art still has the problem of insufficient detection capability when detecting internal defects of composite materials. Summary of the invention

[0005] In view of this, the present invention provides a laser shearing speckle interferometry measuring device with high internal defect detection capability of composite materials.

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

[0007] A laser shearing speckle interferometry measurement device comprises an illumination imaging module, a shearing interference detection module and a control acquisition processing module; the illumination imaging module comprises a laser, a beam expander, an illumination detection beam combiner and an imaging assembly; the illumination detection beam combiner is composed of a light-transmitting area and a reflection area, and the radius of the light-transmitting area is not less than the radius of the circumscribed circle of the imaging assembly image plane; the illumination detection beam combiner is installed at the image plane position of the imaging assembly; the illumination light beam emitted by the laser is expanded by the beam expander, reflected by the reflection area of ​​the illumination detection beam combiner, and then irradiated onto a workpiece to be tested through the imaging assembly; the illumination light beam is reflected by the workpiece to be tested to form a detection light beam, and the detection light beam enters the shearing interference detection module through the light-transmitting area of ​​the illumination detection beam combiner after being imaged by the imaging assembly.

[0008] Preferably, the reflective area of ​​the illumination detection combiner is coated with a reflective film.

[0009] Preferably, the light-transmitting area of ​​the illumination detection beam combiner is a circular through hole or a circular light-transmitting hole, or an anti-reflection film is plated on the circular area.

[0010] Preferably, after the illumination light beam emitted by the laser is expanded by the beam expander, the radius of the light beam irradiated on the illumination detection combiner is not greater than the radius of the circumscribed circle of the image plane of the imaging component.

[0011] Preferably, the shearing amount of the shearing interference detection module can be electrically adjusted.

[0012] Preferably, the shear interference detection module includes a first lens group, a second lens group, a first reflector, a phase shifter, a second reflector, a shear amount electric adjustment mechanism, a dichroic prism and a detector; after the detection light beam passes through the first lens group, it is divided into transmitted light and reflected light by the dichroic prism and irradiates the first reflector and the second reflector respectively; the first lens group and the second lens group form a 4f system, and the front focal plane of the first lens group coincides with the image plane of the imaging component; the rear focal plane of the second lens group coincides with the image plane of the detector; the first reflector is installed on the phase shifter to realize the time phase shift function; the second reflector is installed on the shear amount electric adjustment mechanism to realize the shear amount electric adjustment function.

[0013] Preferably, the control acquisition processing module includes a synchronization trigger and a computer, the synchronization trigger is connected to the phase shifter and the detector to achieve synchronous control triggering of the two; and is connected to the computer to receive relevant trigger commands; the computer controls the laser, the shear amount electric adjustment mechanism, the synchronization trigger, and is connected to the detector to achieve laser control, shear amount adjustment, image data acquisition, transmission, storage, processing and display functions.

[0014] Preferably, the laser shearing speckle interferometry measuring device comprises an excitation tool, and the excitation tool is used to apply excitation to the workpiece during detection.

[0015] Based on the laser shearing speckle interferometry measurement device provided by the present invention, the present invention also provides a defect detection method.

[0016] To achieve this object, the present invention adopts the following technical solutions:

[0017] A defect detection method based on the laser shearing speckle interferometry measurement device provided by the present invention comprises the following steps:

[0018] Step 1: Adjust the relative position between the laser shearing speckle interferometry system and the object to be tested to ensure that the object to be tested is imaged within the detection field of view of the system; adjust the angle of the illumination and detection beam combiner so that the laser illumination area and the detection area basically overlap, and the detection beam is not blocked when passing through the light-transmitting area;

[0019] Step 2: Complete image acquisition, storage, phase extraction and phase difference calculation of the test piece under the loading of the excitation source;

[0020] Step 3: Identify internal defects of the DUT based on the calculated phase difference detection.

[0021] Preferably, the step 2 is specifically:

[0022] Step 2.1: According to the internal defect detection size requirement D of the test piece, set the control adjustment gear of the shearing amount S to K gear, where the shearing amount of each gear is S k , S k =k×D / K, k=1, 2,...,K;

[0023] Step 2.2: Set the current shear amount to S k , turn on the excitation source to load the DUT;

[0024] Step 2.3: Control the phase shifter and detector to achieve the time phase shift and image acquisition of the M group;

[0025] Step 2.4: Turn off the excitation source and complete the series image storage and phase extraction under the current shearing amount;

[0026] Step 2.5: Repeat steps 2.2 to 2.4 until the image acquisition, storage, and phase extraction of the test piece under all shear setting levels are completed;

[0027] Step 2.6: Subtract the series phase extraction results φk,m under each loading to obtain the series phase difference Δφ k,m , Δφ k,m＝ φ k,m+1 -φ k,m, m=1, 2, …, M-1;

[0028] The step 3 is specifically to identify Δφ k,m The abnormal signal in the test piece can be detected and identified to realize the detection and identification of internal defects of the test piece.

[0029] Preferably, the step 3 uses a noise filtering algorithm to process the speckle noise, and uses a machine learning algorithm to identify Δφ k,m Abnormal signal in .

[0030] Preferably, the shearing amount S of each level in steps 2.2 to 2.5 is k All settings are electric settings.

[0031] Preferably, step 2.3 specifically uses a computer to set and control the working timing of the synchronization trigger, and the synchronization trigger controls the phase shifter and the detector to achieve M groups of time phase shift and image acquisition, wherein each group includes N time phase shift and image acquisition, and the number N is determined by the time phase shift algorithm.

[0032] The beneficial effects of the present invention are:

[0033] The laser shearing speckle interferometry measurement device provided by the present invention uses a quasi-common-path illumination and detection method to improve the utilization rate of light energy and reduce the influence of residual reflection of optical elements on detection in view of the low reflectivity of the surface of the composite material; the quasi-common-path method is used to improve the detection sensitivity of the phase change caused by the deformation due to the deeper defects inside the composite material under external excitation, and the synchronous triggering method is used to achieve the coordinated operation of the phase shifter and the detector, thereby improving the collection efficiency of the time phase shift and reducing the influence of environmental interference on the detection accuracy.

[0034] The defect detection method based on the measuring device of the present invention provided by the present invention improves the consistency of illumination detection in the target area, the light energy utilization efficiency and the detection sensitivity due to the quasi-common-path mode, and can effectively improve the detection capability of internal defects; in addition, by setting a shear amount adjustment mode and combining multiple excitations and recognition methods, the detection capability of deeper internal defects is improved, while also reducing the influence of large deformations of shallow internal defects on defect identification and positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the laser shearing speckle interferometry measurement system under thermal excitation for non-destructive testing of aviation composite materials;

[0036] Figure 2 It is a schematic diagram of the structure of the illumination detection combiner;

[0037] Figure 3(a), (b), and (c) are the laser shear speckle interferometry wrapping phase results of a deep 6mm internal diameter defect under the same excitation conditions when the shear amounts in Example A are 2mm, 4mm, and 6mm respectively;

[0038] Figure 4 (a), (b), and (c) are the laser shear speckle interferometry wrapping phase results of a shallow 6mm internal diameter defect under the same excitation conditions when the shear amounts in Example A are 2mm, 4mm, and 6mm, respectively. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings:

[0040] The laser shearing speckle interferometry measurement device provided by the present invention comprises an illumination imaging module, a shearing interference detection module and a control acquisition processing module; the illumination imaging module comprises a laser 1, a beam expander 2, an illumination detection beam combiner 3 and an imaging component 4; the illumination detection beam combiner 3 is composed of a light-transmitting area and a reflection area, and the radius of the light-transmitting area is not less than the radius of the circumscribed circle of the image plane of the imaging component 4; the illumination detection beam combiner 3 is installed at the image plane position of the imaging component 4; the illumination light beam emitted by the laser 1 is expanded by the beam expander 2, reflected by the reflection area of ​​the illumination detection beam combiner 3, and then irradiated onto the object to be measured through the imaging component 4; the illumination light beam is reflected by the object to be measured to form a detection light beam, and the detection light beam is imaged by the imaging component 4 and enters the shearing interference detection module through the light-transmitting area of ​​the illumination detection beam combiner 3.

[0041] The laser shearing speckle interferometry measurement device provided by the present invention improves the consistency of illumination and detection in the target area, the light energy utilization efficiency and the detection sensitivity by designing the illumination light path and the detection light path to be quasi-co-path. When used for internal defect detection of composite materials, it can effectively improve the detection capability of internal defects.

[0042] Specifically, the reflection area of ​​the illumination detection beam combiner 3 is coated with a reflection film.

[0043] Specifically, the light-transmitting area of ​​the illumination detection beam combiner 3 is a circular through hole or a circular light-transmitting hole, or an anti-reflection film is plated on the circular area.

[0044] Specifically, after the illumination light beam emitted by the laser 1 is expanded by the beam expander 2 , the radius of the light beam irradiated on the illumination detection beam combiner 3 is not greater than the radius of the circumscribed circle of the image plane of the imaging component 4 .

[0045] Specifically, the shearing amount of the shearing interference detection module can be electrically adjusted.

[0046] Specifically, the shearing interference detection module includes a first lens group 501, a second lens group 502, a first reflector 6, a phase shifter 7, a second reflector 8, a shearing amount electric adjustment mechanism 9, a beam splitter 10 and a detector 11; after the detection light beam passes through the first lens group 501, it is divided into a transmitted light and a reflected light by the beam splitter 10), and irradiates the first reflector 6 and the second reflector 8 respectively; the first lens group 501 and the second lens group 502 form a 4f system, and the front focal plane of the first lens group 501 coincides with the image plane of the imaging component 4; the rear focal plane of the second lens group 502 coincides with the image plane of the detector 11; the first reflector 6 is installed on the phase shifter 7 to realize the time phase shift function; the second reflector 8 is installed on the shearing amount electric adjustment mechanism 9 to realize the shearing amount electric adjustment function. Among them, the first lens group 501 and the second lens group 502 are used to realize the image transmission function, and the focal length ratio of the two is equal to the ratio of the image plane of the imaging component to the effective area of ​​the detector.

[0047] Specifically, the control acquisition processing module includes a synchronization trigger 12 and a computer 13. The synchronization trigger 12 is connected to the phase shifter 7 and the detector 11 to realize the synchronous control triggering of the two; and is connected to the computer 13 to receive relevant trigger commands; the computer 13 controls the laser 1, the shear amount electric adjustment mechanism 9, the synchronization trigger 12, and is connected to the detector 11 to realize laser control, shear amount adjustment, image data acquisition, transmission, storage, processing and display functions.

[0048] Specifically, the laser shearing speckle interferometry measuring device further includes an excitation tool 14, and the excitation tool 14 is used to apply excitation to the object to be tested 15 during detection.

[0049] The present invention provides a defect detection method based on the laser shearing speckle interferometry measurement device provided by the present invention, comprising the following steps:

[0050] Step 1: Adjust the relative position between the laser shearing speckle interferometry system and the object to be tested to ensure that the object to be tested is imaged within the detection field of view of the system; adjust the angle of the illumination and detection beam combiner so that the laser illumination area and the detection area basically overlap, and the detection beam is not blocked when passing through the light-transmitting area;

[0051] Step 2: Complete image acquisition, storage, phase extraction and phase difference calculation of the test piece under the loading of the excitation source;

[0052] Step 3: Identify internal defects of the DUT based on the calculated phase difference detection.

[0053] The defect detection method based on the measuring device of the present invention provided by the present invention improves the consistency of illumination detection in the target area, the light energy utilization efficiency and the detection sensitivity due to the quasi-common path mode, can effectively improve the detection capability of internal defects, and is suitable for detecting internal defects of aviation composite materials.

[0054] Specifically, the step 2 is:

[0055] Step 2.1: According to the internal defect detection size requirement D of the test piece, set the control adjustment gear of the shearing amount S to K gear, where the shearing amount of each gear is S k , S k =k×D / K, k=1, 2,...,K;

[0056] Step 2.2: Set the current shear amount to S k , turn on the excitation source to load the DUT;

[0057] Step 2.3: Control the phase shifter and detector to achieve the time phase shift and image acquisition of the M group;

[0058] Step 2.4: Turn off the excitation source and complete the series image storage and phase extraction under the current shearing amount;

[0059] Step 2.5: Repeat steps 2.2 to 2.4 until the image acquisition, storage, and phase extraction of the test piece under all shear setting levels are completed;

[0060] Step 2.6: Extract the phase series results φ under each loading k,m Subtract them to get the series phase difference Δφ k,m , Δφ k,m =φ k,m+1 -φ k,m , m=1, 2, …, M-1;

[0061] Specifically, step 3 is to identify Δφ k,m The abnormal signal in the test piece can be detected and identified to realize the detection and identification of internal defects of the test piece.

[0062] Specifically, the step 3 uses a noise filtering algorithm to process speckle noise, and uses a machine learning algorithm to identify Δφ k,m Abnormal signal in .

[0063] Specifically, the shear amount S of each level in steps 2.2 to 2.5 is k All settings are electric settings.

[0064] Specifically, step 2.3 is to use a computer to set and control the working timing of the synchronization trigger, and the synchronization trigger controls the phase shifter and the detector to achieve M groups of time phase shift and image acquisition, where each group includes N time phase shift and image acquisition, and the number N is determined by the time phase shift algorithm.

[0065] The defect detection method based on the measuring device of the present invention provides a quasi-common-path method to improve the internal defect detection capability, and further improves the detection success rate of small-sized and deep internal defects by setting a shear amount adjustment method and combining multiple excitations and identification methods.

[0066] The configuration of Example A is as follows:

[0067] The laser shearing speckle interferometry measurement system includes a 532nm laser 1, a beam expander 2, an illumination detection combiner 3, an imaging component 4 with a focal length of 35mm, a first lens group 501 with a focal length of 50mm, a second lens group 502 with a focal length of 50mm, a first reflector 6, a phase shifter 7 made of piezoelectric ceramic material, a second reflector 8, an electric shearing amount adjustment mechanism 9, a beam splitter prism 10, a detector 11 specifically an industrial camera, a synchronization trigger 12, a computer 13, and a thermal excitation tool 14 as an excitation source.

[0068] The illumination detection beam combiner 3 is installed at the image plane position of the imaging component 4. The radius of the light-transmitting area is equal to the radius of the circumscribed circle of the image plane of the imaging component 4, which is 1 / 3 inch, and is coated with an anti-reflection film. The reflection area is coated with a reflective film of the 532nm band. After the laser 1 is expanded by the beam expander 2, the radius of the beam on the illumination detection beam combiner 3 is equal to the radius of the circumscribed circle of the image plane of the imaging component, which is 1 / 3 inch.

[0069] The first lens group and the second lens group form a 4f system, and the optical path between the two is 100mm; the front focal plane of the first lens group coincides with the image plane of the imaging component; the back focal plane of the second lens group coincides with the image plane of the detector; the first reflector is installed on the phase shifter to realize the time phase shift function; the second reflector is installed on the shear amount electric adjustment mechanism to realize the shear amount electric adjustment function; the synchronization trigger connects the phase shifter and the detector to realize the synchronous control trigger of the two; and is connected to the computer to receive relevant trigger commands; the computer controls the laser, the shear amount electric adjustment mechanism, the synchronization trigger, and is connected to the detector to realize the shear amount adjustment, image data transmission, storage, processing and display functions.

[0070] The internal defect detection method of aviation composite materials based on the laser shearing speckle interferometry measurement device mainly includes the following steps:

[0071] Step 1: Adjust the relative position between the laser shearing speckle interferometry system and the object to be tested to ensure that the object to be tested is imaged within the detection field of view of the system; adjust the angle of the illumination and detection beam combiner so that the laser illumination area and the detection area basically overlap, and the detection beam is not blocked when passing through the light-transmitting area;

[0072] Step 2.1: Taking the requirement of 6mm for the internal defect detection size of aviation composite materials as an example, the electric control adjustment gear of the shear amount S is set to gear 3 (K=3), where S1=2mm, S2=4mm, and S3=6mm;

[0073] Step 2.2: Electric setting of current shearing amount to S k , turn on the excitation source to load the DUT;

[0074] Step 2.3: Use the computer 13 to set and control the working sequence of the synchronization trigger 12, and the synchronization trigger 12 controls the phase shifter 7 and the detector 11 to achieve 10 groups (M=10) of time phase shift and image acquisition, wherein each group includes 4 times (N=4, four-step time phase shift algorithm) of time phase shift and image acquisition;

[0075] Step 2.4: Turn off the excitation source and complete the series image storage and phase extraction under the current shearing amount;

[0076] Step 2.5: Repeat steps 2.2 to 2.4 until the image acquisition, storage, and phase extraction of the test piece under all shear setting levels are completed;

[0077] Step 2.6: Extract the phase series results φ under each loading k,m Subtract them to get the series phase difference Δφ k,m , Δφ k,m =φ k,m+1 -φ k,m , m = 1, 2, ..., 9;

[0078] Step 3: Use a noise filtering algorithm to process speckle noise, and use a machine learning algorithm to identify abnormal signals in Δφk,m, thereby realizing the detection and identification of internal defects of the test piece.

[0079] In Example A, when the shearing amount is 2 mm, 4 mm, and 6 mm respectively, the laser shearing speckle interferometry wrapping phase results of a deep internal diameter 6 mm defect under the same excitation conditions are as follows: Figure 3 As shown in (a), (b), and (c), when the shear amount is small (2 mm), the wrapping phase caused by the defect is not obvious, e.g. Figure 3 As shown in (a), as the shear amount increases, the encapsulation phase caused by the defect becomes clearer, such as Figure 3 (c) to facilitate subsequent identification.

[0080] The results of laser shearing speckle interferometry wrapping phase of the shallow layer with an internal diameter of 6 mm under the same excitation conditions are as follows Figure 4 As shown in (a), (b), and (c), when the shear amount is small (2 mm), the encapsulation phase caused by the defect is obvious, such as Figure 4(a); as the shearing amount increases (6 mm), the encapsulated phase caused by the defect gradually separates, as shown in Figure 4 (c), easily identifiable as two defects.

[0081] Therefore, for internal defects of composite materials of different sizes and depths, subsequent defect identification is facilitated, and different shear amount adjustments and detections are implemented during detection, which is helpful for subsequent internal defect identification.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A laser shearing speckle interferometry device, characterized in that: The invention comprises an illumination imaging module, a shearing interference detection module and a control acquisition processing module; the illumination imaging module comprises a laser (1), a beam expander (2), an illumination detection beam combiner (3) and an imaging component (4); the illumination detection beam combiner (3) is composed of a light-transmitting area and a reflection area, and the radius of the light-transmitting area is not less than the radius of the circumscribed circle of the image plane of the imaging component (4); the illumination detection beam combiner (3) is installed at the image plane position of the imaging component (4); the illumination light beam emitted by the laser (1) is expanded by the beam expander (2), then reflected by the reflection area of ​​the illumination detection beam combiner (3), and then irradiated onto the object to be tested through the imaging component (4); the illumination light beam is reflected by the object to be tested to form a detection light beam, and the detection light beam is imaged by the imaging component (4) and then enters the shearing interference detection module through the light-transmitting area of ​​the illumination detection beam combiner (3).

2. The measuring device according to claim 1, characterized in that: The reflection area of ​​the illumination detection beam combiner (3) is coated with a reflection film, and the light-transmitting area is a circular through hole or a circular light-transmitting hole, or an anti-reflection film is coated on the circular area.

3. The measuring device according to claim 1, characterized in that: After the illumination light beam emitted by the laser (1) is expanded by the beam expander (2), the radius of the light beam irradiated on the illumination detection beam combiner (3) is not greater than the radius of the circumscribed circle of the image plane of the imaging component (4).

4. The measuring device according to claim 1, characterized in that: The shearing amount of the shearing interference detection module can be electrically adjusted.

5. The measuring device according to claim 1, characterized in that: The shearing interference detection module comprises a first lens group (501), a second lens group (502), a first reflector (6), a phase shifter (7), a second reflector (8), a shearing amount electric adjustment mechanism (9), a beam splitter (10) and a detector (11); after the detection light beam passes through the first lens group (501), it is divided into transmitted light and reflected light by the beam splitter (10), and irradiates the first reflector (6) and the second reflector (8) respectively; the first lens group (501) and the second lens group (502) form a 4f system, the front focal plane of the first lens group (501) coincides with the image plane of the imaging component (4); the back focal plane of the second lens group (502) coincides with the image plane of the detector (11); the first reflector (6) is mounted on the phase shifter (7) to realize a time phase shift function; the second reflector (8) is mounted on the shearing amount electric adjustment mechanism (9) to realize a shearing amount electric adjustment function.

6. The measuring device according to claim 5, characterized in that: The control acquisition processing module comprises a synchronous trigger (12) and a computer (13); the synchronous trigger (12) is connected to the phase shifter (7) and the detector (11) to achieve synchronous control triggering of the two; and is connected to the computer (13) to receive relevant trigger commands; the computer (13) controls the laser (1), the shearing amount electric adjustment mechanism (9), the synchronous trigger (12), and is connected to the detector (11) to achieve laser control, shearing amount adjustment, image data acquisition, transmission, storage, processing and display functions.

7. The measuring device according to claim 1, characterized in that: The invention comprises an excitation tool (14), wherein the excitation tool (14) is used to apply excitation to a piece to be tested (15) during testing.

8. A defect detection method based on the laser shearing speckle interferometry device according to any one of claims 1 to 7, characterized in that The following steps are involved: Step 1: Adjust the relative position of the laser shearing speckle interferometry system and the object to be measured to ensure that the object to be measured is imaged within the detection field of view of the system; adjust the angle of the illumination and detection beam combiner (3) so that the laser illumination area and the detection area are basically overlapped, and the detection beam is not blocked when passing through the light-transmitting area; Step 2: Complete image acquisition, storage, phase extraction and phase difference calculation of the test piece under the loading of the excitation source; Step 3: Identify internal defects of the DUT based on the calculated phase difference detection.

9. The method according to claim 8, characterized in that: The step 2 is specifically as follows: Step 2.1: According to the internal defect detection size requirement D of the test piece, set the control adjustment gear of the shearing amount S to K gear, where the shearing amount of each gear is S k , S k =k×D / K, k=1, 2,...,K; Step 2.2: Set the current shear amount to S k , turn on the excitation source to load the DUT; Step 2.3: Control the phase shifter and detector to achieve the time phase shift and image acquisition of the M group; Step 2.4: Turn off the excitation source and complete the series image storage and phase extraction under the current shearing amount; Step 2.5: Repeat steps 2.2 to 2.4 until the image acquisition, storage, and phase extraction of the test piece under all shear setting levels are completed; Step 2.6: Subtract the series phase extraction results φk,m under each loading to obtain the series phase difference Δφ k,m , Δφ k,m =φ k,m+1 -φ k,m , m=1, 2, …, M-1; The step 3 is specifically to identify Δφ k,m The abnormal signal in the test piece can be detected and identified to realize the detection and identification of internal defects of the test piece.

10. The method according to claim 9, characterized in that: Step 3: Use noise filtering algorithm to process speckle noise, and use machine learning algorithm to identify Δφ k,m Abnormal signal in .

11. The method according to claim 9, characterized in that: The shearing amount S for each level in steps 2.2 to 2.5 k All settings are electric settings.

12. The method according to claim 9, characterized in that: Step 2.3 specifically uses a computer to set and control the working timing of the synchronization trigger, and the synchronization trigger controls the phase shifter and the detector to achieve M groups of time phase shift and image acquisition, where each group includes N time phase shift and image acquisition, and the number N is determined by the time phase shift algorithm.

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