CN102878935B - Device and method for measuring optical off-plane displacement field based on shearing speckle interference - Google Patents

Abstract

The invention discloses an optical out-of-plane displacement field measurement device based on shear speckle interference, which comprises a camera provided with a lens, an aperture adjustment device and a focus adjustment device, a first half-mirror, a second half-mirror Mirror, third half mirror, first mirror, second mirror, third mirror, piezoelectric ceramics, voltage controller and computer. At the same time, the invention also discloses a measurement method of an optical out-of-plane displacement field measurement device based on shear speckle interference, which includes the following steps: Step 1. Debugging the test device; Step 2. Before the deformation of the measured sample, collect Phase shift diagram; Step 3. After the measured sample is deformed, collect the phase shift diagram; Step 4. Measure the out-of-plane displacement gradient field; Step 5. Measure the out-of-plane displacement field. Using the measurement device to measure the optical out-of-plane displacement field can make the surface of the tested sample non-destructive, full-field measurement, high resolution, stable measurement result, and convenient on-site measurement.

Description

Optical out-of-plane displacement field measurement device and measurement method based on shear speckle interference

technical field

The invention relates to an out-of-plane displacement measurement technology, in particular to an optical out-of-plane displacement field measurement device and measurement method based on shear speckle interference.

Background technique

For a long time, a large part of the out-of-plane displacement measurement in the industrial field has adopted the traditional contact measurement technology represented by the displacement meter. However, most of these measurement techniques are single-point detection, and it is difficult to obtain the deformation distribution of the whole field. Even if the fast scanning method is adopted, the detection time is relatively long due to the point-by-point measurement, and it is difficult to achieve the problem of synchronizing the states of multiple detection points. . In addition, contact measurement hinders the deformation of the sample surface to a certain extent, and is easy to cause damage to the sample surface, making traditional contact measurement technology unacceptable in more and more new material testing fields. Non-contact triangulation techniques such as structured light projection are limited to high-precision measurement due to their relatively complex calibration and limited accuracy. Ordinary laser electronic speckle interference out-of-plane displacement measurement techniques are due to high vibration isolation and environmental requirements. But it is difficult to apply to the detection in the industrial field.

Contents of the invention

Technical problem: The technical problem to be solved by the present invention is to provide an optical out-of-plane displacement field measurement device and measurement method based on shear speckle interference. When using the measurement device for optical out-of-plane displacement field measurement, the measured The surface of the sample is non-destructive, the whole field is measured, the resolution is high, the measurement result is stable, and it is convenient for on-site measurement.

Technical solution: In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

An optical out-of-plane displacement field measurement device based on shear speckle interference, the measurement device includes a camera with a lens, an aperture adjustment device and a focus adjustment device, a first half-mirror, and a second half-mirror , the third half mirror, the first mirror, the second mirror, the third mirror, piezoelectric ceramics, a voltage controller and a computer; wherein,

The first side of the first half-mirror is opposite to the camera lens of the camera; the second side of the first half-mirror is opposite to the fourth side of the second half-mirror, and the first half-mirror is opposite to the fourth side of the first half-mirror. The third side is opposite to the first side of the third half mirror, the first side of the first half mirror and the third side of the first half mirror are opposite to the first half mirror Two sides, one end of the reflective surface of the first half mirror is positioned at the third side of the first half mirror and the second side connection of the first half mirror, the first half mirror The other end of the reflective surface of the mirror is located at the junction of the first side of the first half-mirror and the fourth side of the first half-mirror;

The second side of the second half-mirror is opposite to the second reflector, a second switch is arranged between the second reflector and the second half-mirror, and the first side of the second half-mirror is in contact with the second half-mirror. The first reflector is opposite, and the first switch is provided between the first reflector and the second half-mirror; the fourth side of the second half-mirror and the second side of the second half-mirror are The opposite two sides of the second half-mirror; one end of the reflective surface of the second half-mirror is positioned at the third side of the second half-mirror and the fourth side of the second half-mirror At the side joint, the other end of the reflective surface of the second half mirror is located at the junction of the first side of the second half mirror and the second side of the second half mirror;

The third side of the third half mirror is opposite to the third reflector, and the first side of the third half mirror and the third side of the third half mirror are opposite to the third half mirror The two sides of the third mirror are provided with piezoelectric ceramics on the side away from the third half mirror, the piezoelectric ceramics are connected to the voltage controller through wires, the voltage controller is connected to the computer, and the camera is connected to the computer.

A measurement method of an optical out-of-plane displacement field measurement device based on shear speckle interference, the measurement method comprising the following steps:

Step 1. Debug the test device: place the sample to be tested so that the sample to be tested is aligned with the fourth side of the first half-mirror, and then illuminate the surface of the sample to be tested with a laser, switching to the x direction and y direction of the image respectively Two shear directions, and calibrate the shear amount of the two shear directions in the x direction and the y direction, where the x direction is the horizontal direction and the y direction is the vertical direction;

Step 2. Before the measured sample is deformed, collect the phase shift diagram: before the measured sample is deformed, switch to the two shear directions of x direction and y direction respectively, use the voltage controller to generate phase shift, and collect the phase shift picture;

Step 3. After the measured sample is deformed, collect the phase shift diagram: load the measured sample to cause the measured sample to have an out-of-plane displacement, and then switch to the two shear directions of the x direction and the y direction respectively, and use the voltage controller Generate a phase shift and collect a phase shift map;

Step 4. Measuring the out-of-plane displacement gradient field: According to the phase shift diagram collected in step 2 and step 3, use the phase shift algorithm to measure and calculate the out-of-plane displacement gradient field along the x direction and y direction;

Step 5. Measure the out-of-plane displacement field: select the initial integration point in the out-of-plane displacement gradient field in the shear direction along the x direction, integrate an out-of-plane displacement curve along the x direction, and then use each point on this curve as Integrate the initial point of integration along the y direction, and then measure the out-of-plane displacement field; or select the initial point of integration in the out-of-plane displacement gradient field along the y shear direction, integrate an out-of-plane displacement curve along the y direction, and then use Each point on this curve is the initial point of integration and is integrated along the x direction, and then the out-of-plane displacement field is measured.

Beneficial effects: compared with the prior art, the present invention has the following beneficial effects:

(1) The surface of the tested sample is not damaged. Compared with the traditional contact measurement technology represented by the displacement meter in the industrial field, the present invention adopts an optical measurement technology, which does not need to be in contact with the surface of the sample to be tested, so there is no damage to the surface of the sample to be tested, and it will not prevent its deformation.

(2) Full field measurement. The traditional method is to use single-point measurement, and it is difficult to obtain the deformation distribution of the whole field. However, in the process of measurement, the present invention images the entire surface of the sample to be tested. The present invention thus has the advantage of full-field measurements.

(3) High resolution and high precision. The laser interferometry technology itself has very high precision and can reach the sensitivity of the wavelength order, and the present invention also inherits this characteristic very well, and has very high resolution and precision.

(4) The measurement result is stable. The technology of measuring out-of-plane displacement by electronic speckle interferometry, which also belongs to the laser interferometry method, is usually limited to the laboratory due to the high requirements for vibration isolation and the environment, and cannot be applied to the industrial site for in-situ measurement. The invention adopts the shearing speckle interference technology without reference light, greatly reduces the requirement for vibration isolation, and the measurement result is more stable than the laser interferometry technology such as electronic speckle interference.

(5) It is convenient for on-site measurement. The measurement method of the invention has low requirements on the measurement environment, is suitable for on-site measurement, and thus has broad application space in the future industrial detection field.

Description of drawings

Fig. 1 is a schematic structural view of the measuring device of the present invention.

Fig. 2 is a schematic diagram of the position of three half-mirrors of the present invention.

Have among the figure: camera 1, the first half mirror 2, the first side 201 of the first half mirror, the second side 202 of the first half mirror, the first half mirror The third side 203, the fourth side 204 of the first half mirror, the second half mirror 3, the first side 301 of the second half mirror, the second side of the second half mirror. Side 302, the third side 303 of the second half mirror, the fourth side 304 of the second half mirror, the third half mirror 4, the first side 401 of the third half mirror , the second side 402 of the third half mirror, the third side 403 of the third half mirror, the fourth side 404 of the third half mirror, the first mirror 5, the second mirror 6. The third mirror 7, the piezoelectric ceramic 8, the voltage controller 9, the computer 10, the first switch 11, the second switch 12, and the sample 13 to be tested.

Detailed ways

The technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figures 1 and 2, an optical out-of-plane displacement field measurement device based on shear speckle interference of the present invention includes a camera 1 provided with a lens, an aperture adjustment device and a focus adjustment device, a first semi-transparent Mirror 2, second half mirror 3, third half mirror 4, first mirror 5, second mirror 6, third mirror 7, piezoelectric ceramics 8, voltage controller 9 and computer 10 . The first side 201 of the first half mirror is opposite to the lens of the camera 1 . The second side 202 of the first half mirror is opposite to the fourth side 304 of the second half mirror. The third side 203 of the first half mirror is opposite to the first side 401 of the third half mirror. The first side 201 of the first half mirror and the third side 203 of the first half mirror are two opposite sides of the first half mirror 2 . The second side 202 of the first half mirror and the fourth side 204 of the first half mirror are two opposite sides of the first half mirror 2 . One end of the reflection surface of the first half mirror 2 is positioned at the third side 203 of the first half mirror and the second side 202 junction of the first half mirror, the first half mirror The other end of the reflective surface of the mirror 2 is located at the junction of the first side 201 of the first half mirror and the fourth side 204 of the first half mirror. The second side 302 of the second half mirror is opposite to the second mirror 6 . A second switch 12 is provided between the second reflector 6 and the second half mirror 3 . If the second switch 12 is in the open state, the light directed to the second reflector 6 and the light reflected by the second reflector 6 will not be affected. If the second switch 12 is in the closed state, the light directed to the second reflector 6 will be completely absorbed by the second switch 12 , so there will be no light reflected from the second reflector 6 . The first side 301 of the second half mirror is opposite to the first mirror 5 . A first switch 11 is provided between the first reflecting mirror 5 and the second half mirror 3 . If the first switch 11 is in the open state, the light directed to the first reflector 5 and the light reflected by the first reflector 5 will not be affected. If the first switch 11 is in the closed state, the light rays directed to the first reflector 5 will be completely absorbed by the first switch 11 , so there will be no light reflected from the first reflector 5 . The first side 301 of the second half-mirror and the third side 303 of the second half-mirror are two opposite sides of the second half-mirror 3, and the fourth side of the second half-mirror The side 304 and the second side 302 of the second half mirror are two opposite sides of the second half mirror 3 . One end of the reflective surface of the second half mirror 3 is positioned at the third side 303 of the second half mirror and the fourth side 304 junction of the second half mirror, and the second half mirror The other end of the reflective surface of the mirror 3 is located at the junction of the first side 301 of the second half mirror and the second side 302 of the second half mirror. The third side 403 of the third half mirror is opposite to the third mirror 7 . The first side 401 of the third half mirror and the third side 403 of the third half mirror are two opposite sides of the third half mirror 4 . The second side 402 of the third half mirror and the fourth side 404 of the third half mirror are two opposite sides of the third half mirror 4 . A piezoelectric ceramic 8 is provided on the side of the third mirror 7 facing away from the third half mirror 4 . The piezoelectric ceramics 8 are connected to the voltage controller 9 through wires, and the voltage controller 9 is connected to the computer 10 . The output voltage of the voltage controller 9 is controlled by the software installed in the computer 10, so that the thickness of the piezoelectric ceramic 8 is changed, and the third reflector 7 is displaced from the plane, and then the light reflected by the third reflector 7 The optical path changes, thereby achieving a phase shift. The video camera 1 is connected to a computer 10 . The camera 1 is controlled by the software installed in the computer 10 so that the camera 1 can collect images and store the images in the computer 10 .

Further, one end of the reflective surface of the third half-mirror 4 is located at the first side 401 of the third half-mirror and the second side 402 junction of the third half-mirror; The other end of the reflective surface of the half mirror 4 is located at the junction of the third side 403 of the third half mirror and the fourth side 404 of the third half mirror. Of course, as another solution, one end of the reflective surface of the third half mirror 4 is connected to the third side 403 of the third half mirror and the second side 402 of the third half mirror. The other end of the reflective surface of the third half mirror 4 is located at the junction of the first side 401 of the third half mirror and the fourth side 404 of the third half mirror.

Further, the first half mirror 2 , the second half mirror 3 , and the third half mirror 4 are all cubes with the same length, height and width. That is to say, the product specifications of the first half mirror 2 , the second half mirror 3 and the third half mirror 4 are the same, which is beneficial to the measurement.

The above-mentioned measuring method of an optical out-of-plane displacement field measuring device based on shear speckle interference comprises the following steps:

Step 1. Debug the test device: place the sample 13 to be tested so that the sample 13 to be tested is aligned with the fourth side 204 of the first half-mirror, then illuminate the surface of the sample 13 to be tested with laser light, and switch to x of the image respectively direction and y direction, and calibrate the shear amount of the two shear directions in x direction and y direction, where the x direction is the horizontal direction and the y direction is the vertical direction.

Step 2. Before the measured sample 13 is deformed, collect a phase shift map: before the measured sample 13 is deformed, switch to the two shearing directions of the x direction and the y direction respectively, use the voltage controller 9 to generate a phase shift, and Acquire a phase shift map.

Step 3. After the measured sample 13 is deformed, collect a phase shift diagram: load the tested sample 13 to cause the measured sample 13 to generate out-of-plane displacement, and then switch to the two shear directions of the x direction and the y direction respectively, using The voltage controller 9 generates the phase shift and acquires a map of the phase shift.

In step 1, step 2 or step 3, switch to the two shearing directions of x direction and y direction respectively, and two methods can be adopted. The first method is: turn on the first switch 11, turn off the second switch 12, rotate the first mirror 5, so that in the image collected by the camera 1, the cutting direction of the image is along the x direction, and then turn off the first switch 11, Turn on the second switch 12 and rotate the second mirror 6 so that in the image captured by the camera 1 , the cutting direction of the image is along the y direction. The second method is: open the first switch 11, close the second switch 12, then rotate the first mirror 5, so that in the image collected by the camera 1, the cutting direction of the image is along the y direction; close the first switch 11, Turn on the second switch 12, and then rotate the second mirror 6, so that in the image captured by the camera 1, the cutting direction of the image is along the x direction.

In step 2 and step 3, utilize voltage controller 9 to produce phase shift, and the method for collecting phase shift figure is: install and run voltage control program in computer 10, utilize voltage control program to change the output voltage of voltage controller 9, thereby Changing the thickness of the piezoelectric ceramic 8 causes the third reflector 7 to be displaced out of plane, and the optical path of the light reflected by the third reflector 7 changes, thereby realizing phase shift, and using the camera 1 to collect a phase shift map, and the The phase shift map is stored in a computer 10 connected to the camera 1 . When purchasing the voltage controller 9, the merchant will provide the user with a voltage control program CD.

Step 4. Measure the out-of-plane displacement gradient field: According to the phase shift diagrams collected in steps 2 and 3, use the phase shift algorithm to measure and calculate the out-of-plane displacement gradient field along the x-direction and y-direction.

In step 4, the phase shift algorithm is prior art. For example, the journal name is "Experimental Mechanics", Issue 03, 2001, and an article titled "Phase Measurement Method in Optical Interferometry" discloses a phase shift algorithm.

Step 5. Measure the out-of-plane displacement field: select the initial integration point in the out-of-plane displacement gradient field in the shear direction along the x direction, integrate an out-of-plane displacement curve along the x direction, and then use each point on this curve as Integrate the initial point of integration along the y direction, and then measure the out-of-plane displacement field; or select the initial point of integration in the out-of-plane displacement gradient field along the y shear direction, integrate an out-of-plane displacement curve along the y direction, and then use Each point on this curve is the initial point of integration and is integrated along the x direction, and then the out-of-plane displacement field is measured.

The present invention uses two steps to measure the out-of-plane displacement field. Among them, the first step is to use shear speckle interferometry to measure the out-of-plane displacement gradient field; the second step is to integrate the out-of-plane displacement gradient field obtained in the first step to calculate the out-of-plane displacement field. The first step in the two-step measurement of the out-of-plane displacement field of the present invention uses the shear speckle interference technology, which naturally has the advantages of non-destructive, non-contact, full-field measurement and fast measurement speed of the optical measurement method. The laser interferometry technology itself has very high precision and can reach the sensitivity of the wavelength order, and the present invention also inherits this characteristic very well, and has very high sensitivity. The technology of measuring out-of-plane displacement by electronic speckle interferometry is usually limited to the laboratory due to the high requirements on vibration isolation and environment, and cannot be applied to the industrial field for in-situ measurement. The present invention adopts the shearing speckle interference technology that does not need reference light, greatly reduces the requirements for vibration isolation and environment, and thus has broad application space in the future industrial detection field.

Conventional shear speckle interferometry can measure the gradient field of the out-of-plane displacement of the sample surface along a certain direction. However, to calculate the displacement field through a single displacement gradient field often encounters the problem that the initial value of the integral cannot be determined. In order to overcome this deficiency, the present invention improves on the basis of classic Michelson interference light path, has adopted the first half mirror 2, the second half mirror 3 and the third half mirror 4 three A half-mirror, and three mirrors of the first reflector 5, the second reflector 6 and the third reflector 7 are used to replace the one half-mirror and the two reflectors in the classic Michelson interference light path. The light reflected by the surface of the tested sample 13 is split by the first half-mirror 2, and one of the reflected lights is irradiated to the third half-mirror 4, and is transmitted to the third reflection through the third half-mirror 4. Mirror 7 is reflected to the third half-mirror 4 through the third reflecting mirror 7, and enters the camera lens through the third half-mirror 4 and the first half-mirror 2. When the first switch 11 is turned on and the second switch 12 is turned off, the light reflected by the surface of the tested sample 13 is split by the first half-mirror 2, and the other transmitted light is irradiated to the second half-mirror 3 , is reflected to the first reflector 5 by the second half mirror 3, is reflected to the second half mirror 3 by the first reflector 5, and is reflected to the first half mirror by the second half mirror 3 through the half-mirror 2, and reflected by the first half-mirror 2 into the lens of the camera 1. When the first switch 11 is closed and the second switch 12 is opened, the light reflected by the surface of the tested sample 13 is split by the first half-mirror 2, and the other transmitted light is irradiated to the second half-mirror 3 , transmitted to the second half mirror 6 through the second half mirror 3, reflected to the second half mirror 3 through the second mirror 6, transmitted through the second half mirror 3 to the first half mirror The half-mirror 2 is reflected by the first half-mirror 2 and enters the lens of the camera 1 . Whether the first switch 11 is turned on and the second switch 12 is turned off, or the first switch 11 is turned off and the second switch 12 is turned on, this optical path can be regarded as a classic Michelson shear optical path, which can be used to measure the measured sample 13 The out-of-plane displacement gradient field of . The deflection directions of the first mirror 5 and the second mirror 6 are adjusted so that the shearing directions of the two shearing images are perpendicular to each other and along the x-direction and y-direction of the image coordinates respectively. Finally, according to the fifth step of the measurement method in the present invention, a seed point is arbitrarily selected, and the out-of-plane displacement field of the sample is obtained by integrating the out-of-plane displacement gradient fields in the x direction and the y direction.

Claims (8)

1. An optical off-plane displacement field measuring device based on shearing speckle interference comprises a camera (1) provided with a lens, an aperture adjusting device and a focusing adjusting device, and a computer (10), and is characterized by further comprising a first half mirror (2), a second half mirror (3), a third half mirror (4), a first reflecting mirror (5), a second reflecting mirror (6), a third reflecting mirror (7), a piezoelectric ceramic (8) and a voltage controller (9);

wherein, the first side surface (201) of the first half mirror is opposite to the lens of the camera (1); the second side face (202) of the first half mirror is opposite to the fourth side face (304) of the second half mirror, the third side face (203) of the first half mirror is opposite to the first side face (401) of the third half mirror, the first side face (201) of the first half mirror and the third side face (203) of the first half mirror are two opposite side faces of the first half mirror (2), one end part of the reflecting face of the first half mirror (2) is positioned at the joint of the third side face (203) of the first half mirror and the second side face (202) of the first half mirror, and the other end part of the reflecting face of the first half mirror (2) is positioned at the joint of the first side face (201) of the first half mirror and the fourth side face (204) of the first half mirror;

a second side surface (302) of the second half mirror is opposite to the second reflecting mirror (6), a second switch (12) is arranged between the second reflecting mirror (6) and the second half mirror (3), a first side surface (301) of the second half mirror is opposite to the first reflecting mirror (5), and a first switch (11) is arranged between the first reflecting mirror (5) and the second half mirror (3); the fourth side face (304) of the second half mirror and the second side face (302) of the second half mirror are two opposite side faces of the second half mirror (3); one end part of the reflecting surface of the second half mirror (3) is positioned at the joint of the third side surface (303) of the second half mirror and the fourth side surface (304) of the second half mirror, and the other end part of the reflecting surface of the second half mirror (3) is positioned at the joint of the first side surface (301) of the second half mirror and the second side surface (302) of the second half mirror;

the third side (403) of the third half mirror is opposite to the third reflector (7), the first side (401) of the third half mirror and the third side (403) of the third half mirror are two opposite sides of the third half mirror (4), one side of the third reflector (7) departing from the third half mirror (4) is provided with a piezoelectric ceramic (8), the piezoelectric ceramic (8) is connected with a voltage controller (9) through a lead, the voltage controller (9) is connected with a computer (10), and the camera (1) is connected with the computer (10).

2. The optical off-plane displacement field measuring device based on shearing speckle interferometry according to claim 1, wherein one end of the reflecting surface of the third half mirror (4) is located at the junction of the first side surface (401) of the third half mirror and the second side surface (402) of the third half mirror; the other end of the reflection surface of the third half mirror (4) is located at the joint of the third side surface (403) of the third half mirror and the fourth side surface (404) of the third half mirror.

3. The optical off-plane displacement field measuring device based on shearing speckle interferometry according to claim 1, wherein one end of the reflecting surface of the third half mirror (4) is located at the junction of the third side surface (403) of the third half mirror and the second side surface (402) of the third half mirror; the other end of the reflection surface of the third half mirror (4) is located at the joint of the first side surface (401) of the third half mirror and the fourth side surface (404) of the third half mirror.

4. The optical off-plane displacement field measuring device based on shearing speckle interference as claimed in claim 1, wherein the first half mirror (2), the second half mirror (3) and the third half mirror (4) are all cubic and have equal length, equal height and equal width.

5. A measuring method of the optical off-plane displacement field measuring device based on the shearing speckle interferometry according to claim 1, characterized by comprising the following steps:

step 1, debugging a testing device: placing a sample to be measured (13), aligning the sample to be measured (13) with the fourth side surface (204) of the first half mirror, then illuminating the surface of the sample to be measured (13) by laser, respectively switching to two shearing directions of an image in the x direction and the y direction, and calibrating the shearing amount of the two shearing directions in the x direction and the y direction, wherein the x direction is a horizontal direction, and the y direction is a vertical direction;

step 2, before the deformation of the tested sample (13), acquiring a phase shift diagram: before a tested sample (13) deforms, switching to two shearing directions of an x direction and a y direction respectively, generating phase shift by using a voltage controller (9), and acquiring a phase shift diagram;

and 3, acquiring a phase shift diagram after the tested sample (13) deforms: loading a measured sample (13), enabling the measured sample (13) to generate out-of-plane displacement, then respectively switching to two shearing directions of an x direction and a y direction, generating phase shift by using a voltage controller (9), and acquiring a phase shift diagram;

step 4, measuring an out-of-plane displacement gradient field: according to the phase shift graphs collected in the step 2 and the step 3, an out-of-plane displacement gradient field along the x direction and the y direction is measured and calculated by using a phase shift algorithm;

step 5, measuring an out-of-plane displacement field: selecting an integration initial point from an off-plane displacement gradient field in the shearing direction along the x direction, integrating an off-plane displacement curve along the x direction, and then integrating along the y direction by taking each point on the curve as an integration initial value point so as to measure the off-plane displacement field; or selecting an integration initial point from the off-plane displacement gradient field along the y shearing direction, integrating an off-plane displacement curve along the y direction, and then integrating along the x direction by taking each point on the curve as an integration initial value point so as to measure the off-plane displacement field.

6. The measuring method of the optical off-plane displacement field measuring device based on the shearing speckle interferometry according to claim 5, wherein in the step 1, the step 2 or the step 3, the method for switching to the two shearing directions of the x direction and the y direction respectively comprises the following steps: the first switch (11) is turned on, the second switch (12) is turned off, then the first reflector (5) is rotated, and the shearing direction of the image is along the x direction in the image collected by the camera (1); the first switch (11) is closed, the second switch (12) is opened, and then the second reflector (6) is rotated, so that the shearing direction of the image in the image acquired by the camera (1) is along the y direction.

7. The measuring method of the optical off-plane displacement field measuring device based on the shearing speckle interferometry according to claim 5, wherein in the step 1, the step 2 or the step 3, the method for switching to the two shearing directions of the x direction and the y direction respectively comprises the following steps: turning on a first switch (11), turning off a second switch (12), and then rotating a first reflector (5) to enable the shearing direction of the image to be along the y direction in the image collected by the camera (1); the first switch (11) is closed, the second switch (12) is opened, and then the second reflector (6) is rotated, so that the image is acquired by the camera (1), and the cutting direction of the image is along the x direction.

8. The measuring method of the optical off-plane displacement field measuring device based on the shearing speckle interferometry according to claim 5, wherein in the step 2 and the step 3, the method for generating the phase shift by using the voltage controller (9) and acquiring the phase shift map comprises the following steps: and a voltage control program is installed and operated on the computer (10), the output voltage of the voltage controller (9) is changed by using the voltage control program, so that the thickness of the piezoelectric ceramic (8) is changed, the third reflector (7) is displaced out of plane, the optical path of light reflected by the third reflector (7) is changed, phase shift is realized, a phase shift diagram is collected by using the camera (1), and the phase shift diagram is stored in the computer (10) connected with the camera (1).