CN102788558A

CN102788558A - Three-dimensional deformation measuring system and three-dimensional deformation measuring method combining speckle correlation and speckle interference

Info

Publication number: CN102788558A
Application number: CN2012102666709A
Authority: CN
Inventors: 孙平; 孙明勇
Original assignee: Shandong Normal University
Current assignee: Shandong Normal University
Priority date: 2012-07-30
Filing date: 2012-07-30
Publication date: 2012-11-21
Anticipated expiration: 2032-07-30
Also published as: CN102788558B

Abstract

The invention relates to a three-dimensional deformation measurement system and method combining speckle correlation and speckle interference, which includes a laser, and the laser beam emitted by the laser is expanded and passed through a half mirror to illuminate the measured object and the reference object surface respectively. The measured object surface and the reference object surface are imaged on the target surface of the CCD camera by the imaging lens through the half mirror at the same time. The half mirror is placed at an angle of 45° to the incident light. When there is a reference light path, the CCD The object plane speckle on the target surface of the camera and the reference plane speckle interfere with each other to form an interference speckle image, and the out-of-plane displacement component is measured. Remove the optical path of the reference object, collect the speckle images on the object surface, and use the two speckle images before and after deformation to calculate the two components of the in-plane displacement. It uses the typical digital speckle optical path sensitive to out-of-plane displacement to realize the in-plane displacement and speckle interference out-of-plane displacement of the speckle-related measurement object, and realizes three-dimensional displacement measurement. It has the advantages of simple optical path, simple and fast operation and data processing .

Description

Three-dimensional deformation measurement system and method combining speckle correlation and speckle interference

技术领域 technical field

本发明涉及一种三维变形测量系统及方法，尤其涉及一种散斑相关和散斑干涉相结合的三维变形测量系统及方法。The invention relates to a three-dimensional deformation measurement system and method, in particular to a three-dimensional deformation measurement system and method combining speckle correlation and speckle interference.

背景技术 Background technique

由I Yamaguchi、W.H.Peters和W.F.Ranson等人提出的数字散斑图像相关方法(DigitalSpeckle Correlation Method，DSCM)在材料力学、断裂力学、生物力学、现场实时测量、微尺度变形场测量、电子封装以及动态位移及变形测试等众多应用领域都展示了其适用性和优越性。数字散斑图像相关技术通过记录物体变形前后的图像并运用一定的图像相关搜索算法得出物体的位移和变形，具有原理简单、光路简单、非接触、对测量环境要求低等优点。近年来，一些现代的数学理论和数学方法逐渐被引入到该方法中，其测量精度逐步的提高，例如运用亚像素搜索算法可获得亚像素位移。亚像素算法有很多种，主要有相关系数拟合法、Newton.Raphson(N-R)迭代法、基于梯度的方法等。与其他方法相比，梯度法具有抗噪能力较高、计算量小、精度较高等优点，在位移小时比较稳定。目前，DSCM应用的领域正逐渐从常规材料的测试向一些新型材料测试、从宏观场逐渐向细微观尺度、从常规环境向比较恶劣的环境、从实验室测试逐步向工程现场应用、从静态准静态向动态准动态等方面发展。The digital speckle image correlation method (Digital Speckle Correlation Method, DSCM) proposed by I Yamaguchi, W.H.Peters and W.F.Ranson et al. Many application fields such as displacement and deformation testing have demonstrated its applicability and superiority. Digital speckle image correlation technology records the images before and after deformation of the object and uses a certain image correlation search algorithm to obtain the displacement and deformation of the object. It has the advantages of simple principle, simple optical path, non-contact, and low requirements for the measurement environment. In recent years, some modern mathematical theories and methods have been gradually introduced into this method, and its measurement accuracy has been gradually improved. For example, sub-pixel displacement can be obtained by using sub-pixel search algorithm. There are many kinds of sub-pixel algorithms, mainly correlation coefficient fitting method, Newton.Raphson (N-R) iterative method, gradient-based method, etc. Compared with other methods, the gradient method has the advantages of high anti-noise ability, small amount of calculation, high precision, etc., and is relatively stable when the displacement is small. At present, the field of DSCM application is gradually changing from conventional material testing to some new material testing, from macroscopic field to microscopic scale, from conventional environment to relatively harsh environment, from laboratory testing to engineering field application, from static quasi- Static to dynamic quasi-dynamic and other aspects of development.

由于方法本身所具有的局限，单光束照明的散斑相关方法只能测量面内位移。科研人员正通过将DSCM与其他测量技术结合或通过三维散斑相关的方法测量三维位移。将DSCM与立体摄影技术或双目测量技术相结合，可以测量三维位移场。例如清华大学姚学锋教授提出的立体摄影术与数字散斑相关方法相结合用于研究三维变形场；谢惠民教授提出的双目三维数字散斑相关测量三维变形和三维面形技术。将DSCM与针孔摄像技术相结合，东南大学何小元教授提出了数字图像相关与针孔摄像机成像模型相结合测量三维物体位移方法。通过三维散斑相关的方法，中国科大伍小平院士、胡小方教授等利用模拟实验获得了物体内部三维位移场。Due to the limitations of the method itself, the speckle correlation method with single-beam illumination can only measure in-plane displacement. Researchers are measuring three-dimensional displacement by combining DSCM with other measurement techniques or by three-dimensional speckle correlation. Combining DSCM with stereophotography or binocular measurement techniques allows the measurement of three-dimensional displacement fields. For example, the combination of stereo photography and digital speckle correlation method proposed by Professor Yao Xuefeng of Tsinghua University is used to study the 3D deformation field; the binocular 3D digital speckle correlation measurement 3D deformation and 3D surface shape technology proposed by Professor Xie Huimin. Combining DSCM with pinhole camera technology, Professor He Xiaoyuan of Southeast University proposed a method for measuring three-dimensional object displacement by combining digital image correlation and pinhole camera imaging model. Through the method of 3D speckle correlation, Academician Wu Xiaoping and Professor Hu Xiaofang of the University of Science and Technology of China used simulation experiments to obtain the 3D displacement field inside the object.

利用电子散斑干涉（ESPI）方法可以测量物体的三维位移，具有非接触，全场测量，精度高的优点。电子散斑干涉技术是基于参考光和物光在CCD靶面上产生散斑干涉进行测量的。因此，三维散斑干涉往往光路比较复杂。复杂的光路增加了测量系统不稳定性，降低了测量精度。The three-dimensional displacement of the object can be measured using the electronic speckle interferometry (ESPI) method, which has the advantages of non-contact, full-field measurement and high precision. Electronic speckle interferometry is based on speckle interference generated by reference light and object light on the CCD target surface for measurement. Therefore, the optical path of 3D speckle interference is often complicated. The complex optical path increases the instability of the measurement system and reduces the measurement accuracy.

将DSCM与散斑干涉相结合，也可以测量三维位移场。张青川教授采用二套光路，对试件正面采用散斑相关测量，对试件的反面采用散斑干涉测量，实现了三维位移场测量。该方法是对试件的不同表面测量，不是同一个表面的三维变形。周灿林教授等把散斑相关和电子散斑干涉结合起来测量变形，采用的是典型的散斑相关光路，首先对散斑干涉四步相移所采集的散斑干涉图像进行处理，然后对处理过的图像进行散斑相关计算，从而获得三维变形场。所用的原理则很复杂，图像处理过程也很复杂，利用散斑相关计算面内位移时不是直接得到所需的散斑图，而是由变形前后采集的相移图像经过处理得到，实际操作中很难获得三维变形场的数值。Combining DSCM with speckle interferometry, it is also possible to measure three-dimensional displacement fields. Professor Zhang Qingchuan used two sets of optical paths, speckle correlation measurement on the front side of the specimen, and speckle interferometry on the back side of the specimen, realizing the three-dimensional displacement field measurement. This method is to measure different surfaces of the test piece, not the three-dimensional deformation of the same surface. Professor Zhou Canlin combined speckle correlation and electronic speckle interferometry to measure deformation. They used a typical speckle correlation optical path. Speckle correlation calculation is performed on the image to obtain a three-dimensional deformation field. The principle used is very complicated, and the image processing process is also very complicated. When using speckle correlation to calculate the in-plane displacement, the required speckle image is not obtained directly, but is obtained by processing the phase-shifted images collected before and after deformation. In actual operation It is difficult to obtain numerical values for 3D deformation fields.

发明内容 Contents of the invention

本发明的目的就是为了解决上述问题，提供一种散斑相关和散斑干涉相结合的三维变形测量系统及方法，它利用典型的对离面位移敏感的迈克尔逊散斑光路，通过控制光路中的参考光，实现散斑相关测量物体的面内位移和散斑干涉测量离面位移，实现了三维位移测量，该方法具有光路简单、操作和数据处理简单快捷的优点。The purpose of the present invention is to solve the above problems, and provide a three-dimensional deformation measurement system and method combining speckle correlation and speckle interference. With the reference light, the in-plane displacement of the object can be measured by speckle correlation and the out-of-plane displacement can be measured by speckle interferometry, and the three-dimensional displacement measurement can be realized. This method has the advantages of simple optical path, simple and fast operation and data processing.

为了实现上述目的，本发明采用如下技术方案：In order to achieve the above object, the present invention adopts the following technical solutions:

一种散斑相关和散斑干涉相结合的三维变形测量系统，激光器发出的激光送入扩束镜；扩束镜后方设有与入射光线成45°角倾斜放置的半透半反镜，半透半反镜的反射光照射到被测物，透射光则照射到参考物面，参考物面与PZT相移器连接构成参考相移光路；被测物的散斑图像经过半透半反镜由成像透镜成像在CCD摄像机上，利用被测物变形前后的两幅散斑图，计算出面内位移的二个分量；在参考光路工作时被测物表面的散斑图像与参考物面的散斑图像形成干涉散斑图像，并由成像透镜成像在CCD摄像机上，测量物体离面位移分量。A three-dimensional deformation measurement system that combines speckle correlation and speckle interference. The laser light emitted by the laser is sent to the beam expander; behind the beam expander is a half-transparent and half-reflective mirror placed at an angle of 45° to the incident light. The reflected light of the half-mirror is irradiated to the measured object, and the transmitted light is irradiated to the reference object plane. The reference object plane is connected with the PZT phase shifter to form a reference phase shift optical path; The imaging lens is imaged on the CCD camera, and the two speckle images before and after the deformation of the measured object are used to calculate the two components of the in-plane displacement; when the reference optical path works, the speckle image on the surface of the measured object and the scattered The speckle image forms an interference speckle image, which is imaged on the CCD camera by the imaging lens, and the out-of-plane displacement component of the object is measured.

一种采用散斑相关和散斑干涉相结合的三维变形测量系统的测量方法，它通过控制参考光路，将数字散斑相关和散斑干涉结合起来测量物体的三维变形；具体过程为：首先在无参考光路的参考激光时采集一幅被测物变形前的散斑图；然后加入参考光路的参考激光实现散斑干涉；加载使被测物变形，结合相移技术测量被测物离面位移；最后去掉参考激光再采集一幅被测物变形后的散斑图；对被测物变形前后散斑图进行散斑相关运算，得到二维面内位移分量，从而实现三维变形测量。A measurement method of a three-dimensional deformation measurement system that uses a combination of speckle correlation and speckle interference. It measures the three-dimensional deformation of an object by controlling the reference optical path and combining digital speckle correlation and speckle interference; the specific process is: first in When there is no reference laser in the reference optical path, collect a speckle image of the measured object before deformation; then add the reference laser in the reference optical path to realize speckle interference; load to deform the measured object, and measure the out-of-plane displacement of the measured object with phase shift technology ; Finally, remove the reference laser and collect a speckle image after deformation of the measured object; perform speckle correlation calculation on the speckle image before and after deformation of the measured object to obtain two-dimensional in-plane displacement components, thereby realizing three-dimensional deformation measurement.

本发明的具体步骤是：Concrete steps of the present invention are:

步骤一：参考物面的反射光构成参考光；在无参考光时，利用CCD采集被测物变形前的散斑图；Step 1: The reflected light of the reference object surface constitutes the reference light; when there is no reference light, use the CCD to collect the speckle pattern of the measured object before deformation;

步骤二：加入参考光路的参考光，实现数字散斑干涉；Step 2: Add the reference light of the reference light path to realize digital speckle interference;

步骤三：加载使被测物变形，结合四步相移技术测量被测物离面位移w场；Step 3: Load to deform the measured object, and measure the out-of-plane displacement w field of the measured object with the four-step phase shift technology;

步骤四：去掉参考光；利用CCD采集被测物变形后的散斑图；Step 4: Remove the reference light; use the CCD to collect the speckle pattern after the deformation of the measured object;

步骤五：结合步骤一的被测物变形前的散斑图和步骤四的被测物变形后的散斑图，对被测物变形前后散斑图进行散斑相关运算，得到二维面内位移分量u、v场。Step 5: Combining the speckle pattern of the measured object before deformation in step 1 and the speckle pattern of the measured object after deformation in step 4, perform speckle correlation calculation on the speckle pattern of the measured object before and after deformation to obtain the two-dimensional in-plane Displacement component u, v field.

所述步骤三中离面位移为垂直于物体表面方向的位移w场，具体测量过程为：The out-of-plane displacement in the step 3 is the displacement w field perpendicular to the direction of the object surface, and the specific measurement process is:

根据光波相位变化与物体变形之间的关系：According to the relationship between the phase change of the light wave and the deformation of the object:

其中，λ是所用激光的波长，θ是照明光与物体表面法线的夹角，w是物体变形的离面位移，u是物体变形的面内水平方向位移；由式（4）知，当照明光入射角度θ=0时，有：Among them, λ is the wavelength of the laser used, θ is the angle between the illumination light and the surface normal of the object, w is the out-of-plane displacement of the object deformation, and u is the in-plane horizontal displacement of the object deformation; from formula (4), when When the illumination light incident angle θ=0, there are:

采用已有的相移技术，计算物体变形相位

进而得出离面位移w场。Calculate the deformation phase of the object by using the existing phase shift technology

Then the out-of-plane displacement w field is obtained.

所述步骤五的具体步骤为：所述二维面内位移分量为水平方向位移分量u和竖直方向位移分量v，散斑相关计算利用公式（1），The specific steps of the step five are: the two-dimensional in-plane displacement components are the horizontal displacement component u and the vertical displacement component v, and the speckle correlation calculation uses the formula (1),

$C C ((u u,, v v)) = = \frac{{Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} [[f f (({x x}_{i i},, {y the y}_{i i})) - - \overset{&OverBar; &OverBar;}{f f}]] [[g g (({x x}_{i i} + + u u,, {y the y}_{j j} + + v v)) - - \overset{&OverBar; &OverBar;}{g g}]]}{\sqrt{{Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} {[[f f (({x x}_{i i},, {y the y}_{j j})) - - \overset{&OverBar; &OverBar;}{f f}]]}^{22}} \sqrt{{Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} {[[g g (({x x}_{i i} + + u u,, {y the y}_{j j} + + v v)) - - \overset{&OverBar; &OverBar;}{g g}]]}^{22}}} - - - - - - ((11))$

其中，f(x，y)为变形前的图像，(x_i,y_j)为变形前图像中的任意一个位移点，g(x′，y′)为变形后的图像，u、v分别对应原图像中位移点(x，y)在变形后的图像中对应点(x′，y′)的整像素位移，(x_i+u,y_j+v)为位移点(x_i,y_j)中的x_i移动了u和y_j移动了v得到的变形后的图像中的位移点，

和

为图像子区灰度平均值；Among them, f(x, y) is the image before deformation, ( _xi , y _j ) is any displacement point in the image before deformation, g(x′, y′) is the image after deformation, u and v respectively Corresponding to the integer pixel displacement of the displacement point (x, y) in the original image and the corresponding point (x′, y′) in the deformed image, ( _xi + u, y _j + v) is the displacement point ( _xi , y x _i in _j ) moves u and y _j moves the displacement point in the deformed image obtained by v,

and

is the average gray value of the image sub-area;

为了提高测量精度，在公式（1）的基础上利用梯度算法进一步进行亚像素位移的计算求解，梯度法所选取的相关系数计算公式为式（1）的平方，即式（2）；In order to improve the measurement accuracy, the gradient algorithm is used to further calculate and solve the sub-pixel displacement on the basis of formula (1). The correlation coefficient calculation formula selected by the gradient method is the square of formula (1), that is, formula (2);

$C C ((u u,, v v)) = = \frac{{{{Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} [[f f (({x x}_{i i},, {y the y}_{j j})) - - \overset{&OverBar; &OverBar;}{f f}]] [[g g (({x x}_{i i} + + u u + + Δu Δ u,, {y the y}_{j j} + + v v + + Δv Δv)) - - \overset{&OverBar; &OverBar;}{g g}]]}}^{22}}{{Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} {[[f f (({x x}_{i i},, {y the y}_{j j})) - - \overset{&OverBar; &OverBar;}{f f}]]}^{22} {Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} {[[g g (({x x}_{i i} + + u u + + Δu Δu,, {y the y}_{j j} + + v v + + Δv Δv)) - - \overset{&OverBar; &OverBar;}{g g}]]}^{22}} - - - - - - ((22))$

其中，Δu、Δv为对应于整像素位移结果的亚像素位移，(x_i+u+Δu,y_j+v+Δv)为位移点(x_i,y_j)中的x_i移动了u+Δu和y_j移动了v+Δv得到的变形后的图像中的位移点；Among them, Δu and Δv are the sub-pixel displacement corresponding to the whole pixel displacement result, and ( _xi +u+Δu,y _j +v+Δv) is the displacement point ( _xi ,y _j ) where x _i moves by u+ Δu and y _j move the displacement point in the deformed image obtained by v+Δv;

将

泰勒展开，取一级近似，并令

经推导得：Will

Taylor expansion, take a first-order approximation, and let

It was deduced that:

$[\begin{matrix} Δu Δu \\ Δv Δv \end{matrix}] = = {[\begin{matrix} B B & C C \\ E E. & H h \end{matrix}]}^{- - 11} [\begin{matrix} A A \\ D D. \end{matrix}] - - - - - - ((33))$

其中in

$A A = = {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{x x} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{x x} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}^{22},,$

$B B = = {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{x x} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{x x} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}_{x x}^{22} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG,,$

$C C = = 22 {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{x x} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{y the y} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{x x} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{y the y} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}_{x x} {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG,,$

$D D. = = {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{y the y} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}^{22},,$

$E E. = = 22 {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{x x} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{x x} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}_{x x} {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG,,$

$H h = = {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{y the y} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}_{y the y}^{22} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG,,$

$G G = = g g (({x x}_{i i} + + u u,, {y the y}_{j j} + + v v)) - - \overset{&OverBar; &OverBar;}{g g},,$

${G G}_{x x} = = {g g}_{x x} - - {\overset{&OverBar; &OverBar;}{g g}}_{x x},, {G G}_{y the y} = = {g g}_{y the y} - - {\overset{&OverBar; &OverBar;}{g g}}_{y the y},,$

$F f = = f f (({x x}_{i i},, {y the y}_{j j})) - - \overset{&OverBar; &OverBar;}{f f},,$

式中，G_x表示G对x_i求偏导，G_y表示G对y_j求偏导，g_x表示g(x_i+u,y_j+v)对x_i求偏导，g_y表示g(x_i+u,y_j+v)对y_j求偏导，

表示

对x_i求偏导，

表示

对y_j求偏导，m为迭代次数。In the formula, G _x represents the partial derivative of G for x _i , G _y represents the partial derivative of G for y _j , g _x represents the partial derivative of g( _xi +u, y _j +v) for x _i , g _y represents g(x _i +u,y _j +v) finds the partial derivative of y _j ,

express

Take the partial derivative of x _i ,

express

Find the partial derivative for y _j , m is the number of iterations.

本发明的有益效果：利用典型的对离面位移敏感的数字散斑干涉光路，通过控制光路中的参考光，实现了散斑相关测量物体的面内位移和散斑干涉测量离面位移，实现了三维位移测量。该方法具有光路简单、操作和数据处理简单快捷的优点。Beneficial effects of the present invention: by using a typical digital speckle interference optical path sensitive to out-of-plane displacement, by controlling the reference light in the optical path, the in-plane displacement of the speckle-related measurement object and the out-of-plane displacement measured by speckle interferometry are realized. Three-dimensional displacement measurement. The method has the advantages of simple optical path, simple and rapid operation and data processing.

附图说明Description of drawings

图1为光学测量系统图；Figure 1 is a diagram of the optical measurement system;

图2为未变形时的散斑图像；Figure 2 is the speckle image without deformation;

图3为变形后的离面干涉条；Figure 3 is the deformed out-of-plane interference strip;

图4为变形后的散斑图像；Figure 4 is the deformed speckle image;

图5为物体变形后的三维位移分量，水平方向u场图；Figure 5 is the three-dimensional displacement component after the deformation of the object, and the u field diagram in the horizontal direction;

图6为物体变形后的三维位移分量，垂直方向v场图；Fig. 6 is the three-dimensional displacement component after the deformation of the object, and the v-field diagram in the vertical direction;

图7为物体变形后的三维位移分量，离面位移w场图；Fig. 7 is the three-dimensional displacement component after the deformation of the object, and the out-of-plane displacement w field diagram;

图8为本发明的流程图。Fig. 8 is a flowchart of the present invention.

其中，1.激光器，2.扩束镜，3.半透半反镜，4.被测物，5.参考物面，6.PZT相移器，7.成像透镜，8.CCD摄像机。Among them, 1. Laser, 2. Beam expander, 3. Half mirror, 4. Measured object, 5. Reference object plane, 6. PZT phase shifter, 7. Imaging lens, 8. CCD camera.

具体实施方式 Detailed ways

下面结合附图与实施例对本发明作进一步说明。The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

图1中，一种散斑相关和散斑干涉相结合的三维变形测量系统，它包括测量物体面内变形分量的散斑相关光路和测量离面位移分量的散斑干涉相移光路；激光器1发出的激光扩束后通过半透半反镜3分别照明被测物面4和参考物面5。半透半反镜3与入射光成45°角倾斜放置。物面4的反射光透过半透半反镜3，参考物面5的反射光在半透半反镜3上反射，二束光经过成像透镜7后会聚在CCD摄像机8上。In Fig. 1, a three-dimensional deformation measurement system combining speckle correlation and speckle interference, it includes a speckle correlation optical path for measuring the deformation component in the object plane and a speckle interferometric phase shift optical path for measuring the out-of-plane displacement component; laser 1 After the emitted laser beam is expanded, the measured object surface 4 and the reference object surface 5 are respectively illuminated by the half mirror 3 . The half mirror 3 is placed obliquely at an angle of 45° to the incident light. The reflected light of the object plane 4 passes through the half-mirror 3 , the reflected light of the reference object plane 5 is reflected on the half-mirror 3 , and the two beams of light converge on the CCD camera 8 after passing through the imaging lens 7 .

实验光路如图1所示,试件为有机玻璃简支梁，长150.0mm，高19.5mm，厚18.5mm。在简支梁表面涂以水性涂料，以增强其反射率，整个实验装置放置在防震平台上进行。用He-Ne激光器1作为光源，光束经扩束镜2扩束后照射在简支梁表面上。由半透半反镜3（BS）分出的另一束光作为参考光。实验时，如图8所示的流程图，首先挡住参考光采集一幅简支梁未变形时的散斑图像，如图2所示；然后加上参考光，实现电子散斑干涉；采集物体散斑干涉图像并实时相减，期间对简支梁进行加载，可以观察到物体离面位移条纹，如图3所示；使用PZT相移器6实现等相移并采集散斑干涉条纹图；最后，挡住参考光，再次采集简支梁变形后的散斑图像，如图4所示。The optical path of the experiment is shown in Figure 1. The specimen is a simply supported plexiglass beam with a length of 150.0mm, a height of 19.5mm, and a thickness of 18.5mm. The surface of the simply supported beam is coated with water-based paint to enhance its reflectivity, and the entire experimental device is placed on a shockproof platform. Using a He-Ne laser 1 as a light source, the beam is expanded by a beam expander 2 and irradiated on the surface of a simply supported beam. Another beam of light split by the half-mirror 3 (BS) is used as a reference light. During the experiment, as shown in the flow chart in Figure 8, first block the reference light to collect a speckle image when the simply supported beam is not deformed, as shown in Figure 2; then add the reference light to realize electronic speckle interference; collect the object The speckle interference images are subtracted in real time, during which the simply supported beam is loaded, and the out-of-plane displacement fringes of the object can be observed, as shown in Figure 3; use the PZT phase shifter 6 to achieve equal phase shift and collect speckle interference fringe images; Finally, the reference light is blocked, and the speckle image of the deformed simply supported beam is collected again, as shown in Fig. 4 .

所述二维面内位移分量为：利用公式（1）The two-dimensional in-plane displacement component is: using the formula (1)

和为图像子区灰度平均值；Among them, f(x, y) is the image before deformation, ( _xi , y _j ) is any displacement point in the image before deformation, g(x′, y′) is the image after deformation, u and v respectively Corresponding to the integer pixel displacement of the displacement point (x, y) in the original image and the corresponding point (x′, y′) in the deformed image, ( _xi + u, y _j + v) is the displacement point ( _xi , y x _i in _j ) moves u and y _j moves the displacement point in the deformed image obtained by v,

and is the average gray value of the image sub-area;

为了提高测量精度，在公式（1）的基础上利用已有的梯度法进一步进行亚像素位移的计算，梯度法所选取的相关系数计算公式为式（1）的平方，即式（2）In order to improve the measurement accuracy, on the basis of formula (1), the existing gradient method is used to further calculate the sub-pixel displacement. The calculation formula of the correlation coefficient selected by the gradient method is the square of formula (1), that is, formula (2)

$C C ((u u,, v v)) = = \frac{{{{Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} [[f f (({x x}_{i i},, {y the y}_{j j})) - - \overset{&OverBar; &OverBar;}{f f}]] [[g g (({x x}_{i i} + + u u + + Δu Δu,, {y the y}_{j j} + + v v + + Δv Δv)) - - \overset{&OverBar; &OverBar;}{g g}]]}}^{22}}{{Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} {[[f f (({x x}_{i i},, {y the y}_{j j})) - - \overset{&OverBar; &OverBar;}{f f}]]}^{22} {Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} {[[g g (({x x}_{i i} + + u u + + Δu Δu,, {y the y}_{j j} + + v v + + Δv Δv)) - - \overset{&OverBar; &OverBar;}{g g}]]}^{22}} - - - - - - ((22))$

其中，Δu、Δv为对应于整像素位移结果的亚像素位移；Among them, Δu and Δv are sub-pixel displacements corresponding to the result of integer pixel displacement;

将泰勒展开，取一级近似，并令

经推导得：Will Taylor expansion, take a first-order approximation, and let

It was deduced that:

其中in

$H h = = {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{y the y} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}_{y the y}^{22} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG . .$

$G G (({x x}_{i i},, {y the y}_{j j})) = = g g (({x x}_{i i} + + u u,, {y the y}_{j j} + + v v)) - - \overset{&OverBar; &OverBar;}{g g},,$

$F f (({x x}_{i i},, {y the y}_{i i})) = = f f (({x x}_{i i},, {y the y}_{j j})) - - \overset{&OverBar; &OverBar;}{f f},,$

表示对x_i求偏导，

表示

express Take the partial derivative of x _i ,

express

Find the partial derivative for y _j , m is the number of iterations.

所述离面位移测量过程为：The out-of-plane displacement measurement process is:

光波相位变化与物体变形的相位关系为：The phase relationship between light wave phase change and object deformation is:

其中，λ是所用激光的波长，θ是照明光与物体表面法线的夹角，w是物体变形的离面位移，u是物体变形的面内水平方向位移；由式（4）知，当照明光入射角度θ小于5°时近似看成光程变化仅与离面位移w有关，由式（4）得：Among them, λ is the wavelength of the laser used, θ is the angle between the illumination light and the surface normal of the object, w is the out-of-plane displacement of the object deformation, and u is the in-plane horizontal displacement of the object deformation; from formula (4), when When the incident angle θ of the illumination light is less than 5°, it can be regarded as that the optical path change is only related to the out-of-plane displacement w. From formula (4):

采用相移技术计算物体变形相位

进而得出w场。Calculation of object deformation phase using phase shift technology

Then get w field.

变形前后散斑图像（图2和图4）用于散斑相关计算面内位移u场和v场(单位：像素)。采用已有的相移技术对散斑干涉条纹图进行处理，可以得到离面位移w场（单位：微米）。变形梁三维变形分量实验结果如图5、图6、图7所示。The speckle images before and after deformation (Fig. 2 and Fig. 4) are used to calculate the in-plane displacement u field and v field (unit: pixel) for speckle correlation. Using the existing phase shifting technology to process the speckle interference fringe pattern, the out-of-plane displacement w field (unit: micron) can be obtained. The experimental results of the three-dimensional deformation components of the deformed beam are shown in Fig. 5, Fig. 6 and Fig. 7.

实验结果表明，利用散斑相关和散斑干涉相结合的方法可以快速有效的测量物体三维变形，具有光路简单易操作、数据处理简单的优点。实验结果v、w场与文献[孙平，范香菊，王兴海.基于大错位方棱镜的三维载频电子散斑干涉技术[J].光学学报，2011，31(4)：0412012]中的结果吻合的较好，u场基本吻合。The experimental results show that the combination of speckle correlation and speckle interference can quickly and effectively measure the three-dimensional deformation of the object, and has the advantages of simple optical path, easy operation and simple data processing. The experimental results of v and w fields are consistent with the results in the literature [Sun Ping, Fan Xiangju, Wang Xinghai. Three-dimensional carrier-frequency electron speckle interference technology based on large misaligned square prisms [J]. Acta Optics Sinica, 2011, 31(4): 0412012] The better, the u field basically coincides.

上述虽然结合附图对本发明的具体实施方式进行了描述，但并非对本发明保护范围的限制，所属领域技术人员应该明白，在本发明的技术方案的基础上，本领域技术人员不需要付出创造性劳动即可做出的各种修改或变形仍在本发明的保护范围以内。Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims

1. A three-dimensional deformation measurement system combining speckle correlation and speckle interference, which is characterized in that the laser light emitted by the laser is sent into the beam expander; behind the beam expander, there is a semi The half-mirror, the reflected light of the half-mirror is irradiated to the measured object, and the transmitted light is irradiated to the reference object plane, and the reference object plane is connected with the PZT phase shifter to form a reference optical path; the speckle image of the measured The half-mirror is imaged on the CCD camera by the imaging lens, and the two speckle images before and after the deformation of the measured object are used to calculate the two components of the in-plane displacement; when the reference optical path works, the speckle image on the surface of the measured object The speckle image on the object surface forms an interference speckle image, which is imaged on the CCD camera by the imaging lens, and the off-plane displacement component of the object is measured.

2. A measurement method using a three-dimensional deformation measurement system combining speckle correlation and speckle interference according to claim 1, characterized in that it combines digital speckle correlation and speckle interference by controlling the reference optical path Measure the three-dimensional deformation of the object; the specific process is: firstly, when there is no reference laser of the reference optical path, collect a speckle image of the measured object before deformation; then add the reference laser of the reference optical path to realize speckle interference; load to deform the measured object , combined with phase shift technology to measure the out-of-plane displacement of the measured object; finally remove the reference laser and collect a speckle image after the deformation of the measured object; perform speckle correlation calculation on the speckle image before and after the deformation of the measured object to obtain a two-dimensional In-plane displacement components to achieve three-dimensional deformation measurement.

3. The measurement method of the three-dimensional deformation measurement system combining speckle correlation and speckle interference as claimed in claim 2, characterized in that, the specific steps are:

Step 1: The reflected light of the reference object surface constitutes the reference light; when there is no reference light, use the CCD to collect the speckle pattern of the measured object before deformation;

Step 2: Add the reference light of the reference light path to realize digital speckle interference;

Step 3: Load to deform the measured object, and measure the out-of-plane displacement w field of the measured object with the four-step phase shift technology;

Step 4: Remove the reference light; use the CCD to collect the speckle pattern after the deformation of the measured object;

Step 5: Combining the speckle pattern of the measured object before deformation in step 1 and the speckle pattern of the measured object after deformation in step 4, perform speckle correlation calculation on the speckle pattern of the measured object before and after deformation to obtain the two-dimensional in-plane Displacement component u, v field.

4. The measurement method of a three-dimensional deformation measurement system combining speckle correlation and speckle interference as claimed in claim 3, wherein the out-of-plane displacement in step 3 is the displacement w field perpendicular to the direction of the object surface. The measurement process is:

According to the phase relationship between light wave phase change and object deformation:

Among them, λ is the wavelength of the laser used, θ is the angle between the illumination light and the surface normal of the object, w is the out-of-plane displacement of the object deformation, and u is the in-plane horizontal displacement of the object deformation; from formula (4), when When the illumination light incident angle θ=0, there are:

Calculate the deformation phase of the object by using the existing phase shift technology

Then get w field.

5. The measurement method of a three-dimensional deformation measurement system combining speckle correlation and speckle interference as claimed in claim 3, characterized in that, the specific step of step five is: the two-dimensional in-plane displacement component is horizontal Directional displacement component u and vertical displacement component v, speckle correlation calculation using formula (1),

C C ((u u,, v v)) = = \frac{{Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} [[f f (({x x}_{i i},, {y the y}_{i i})) - - \overset{&OverBar; &OverBar;}{f f}]] [[g g (({x x}_{i i} + + u u,, {y the y}_{j j} + + v v)) - - \overset{&OverBar; &OverBar;}{g g}]]}{\sqrt{{Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} {[[f f (({x x}_{i i},, {y the y}_{j j})) - - \overset{&OverBar; &OverBar;}{f f}]]}^{22}} \sqrt{{Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} {[[g g (({x x}_{i i} + + u u,, {y the y}_{j j} + + v v)) - - \overset{&OverBar; &OverBar;}{g g}]]}^{22}}} - - - - - - ((11))

Among them, f(x, y) is the image before deformation, ( _xi , y _j ) is any displacement point in the image before deformation, g(x′, y′) is the image after deformation, u and v respectively Corresponding to the integer pixel displacement of the displacement point (x, y) in the original image and the corresponding point (x′, y′) in the deformed image, ( _xi + u, y _j + v) is the displacement point ( _xi , y x _i in _j ) moves u and y _j moves the displacement point in the deformed image obtained by v,

and

is the average gray value of the image sub-area;

In order to improve the measurement accuracy, on the basis of formula (1), the existing gradient algorithm is used to calculate and solve the sub-pixel displacement. The calculation formula of the correlation coefficient selected by the gradient method is the square of formula (1), that is, formula (2);

C C ((u u,, v v)) = = \frac{{{{Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} [[f f (({x x}_{i i},, {y the y}_{j j})) - - \overset{&OverBar; &OverBar;}{f f}]] [[g g (({x x}_{i i} + + u u + + Δu Δu,, {y the y}_{j j} + + v v + + Δv Δv)) - - \overset{&OverBar; &OverBar;}{g g}]]}}^{22}}{{Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} {[[f f (({x x}_{i i},, {y the y}_{j j})) - - \overset{&OverBar; &OverBar;}{f f}]]}^{22} {Σ Σ}_{i i}^{m m} {Σ Σ}_{j j}^{m m} {[[g g (({x x}_{i i} + + u u + + Δu Δu,, {y the y}_{j j} + + v v + + Δv Δv)) - - \overset{&OverBar; &OverBar;}{g g}]]}^{22}} - - - - - - ((22))

Among them, Δu and Δv are sub-pixel displacements corresponding to the result of integer pixel displacement;

Will

Taylor expansion, take a first-order approximation, and let

It was deduced that:

[\begin{matrix} Δu Δu \\ Δv Δv \end{matrix}] = = {[\begin{matrix} B B & C C \\ E E. & H h \end{matrix}]}^{- - 11} [\begin{matrix} A A \\ D D. \end{matrix}] - - - - - - ((33))

in

A A = = {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{x x} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{x x} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}^{22},,

B B = = {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{x x} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{x x} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}_{x x}^{22} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG,,

C C = = 22 {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{x x} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{y the y} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{x x} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{y the y} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}_{x x} {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG,,

D D. = = {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{y the y} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}^{22},,

E E. = = 22 {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{x x} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{x x} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}_{x x} {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG,,

H h = = {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} F f {G G}_{y the y} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} G G {G G}_{y the y} - - {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} {G G}_{y the y}^{22} {Σ Σ}_{i i = = 11}^{m m} {Σ Σ}_{j j = = 11}^{m m} FG FG,,

G G (({x x}_{i i},, {y the y}_{j j})) = = g g (({x x}_{i i} + + u u,, {y the y}_{j j} + + v v)) - - \overset{&OverBar; &OverBar;}{g g},,

{G G}_{x x} = = {g g}_{x x} - - {\overset{&OverBar; &OverBar;}{g g}}_{x x},, {G G}_{y the y} = = {g g}_{y the y} - - {\overset{&OverBar; &OverBar;}{g g}}_{y the y},,

F f (({x x}_{i i},, {y the y}_{j j})) = = f f (({x x}_{i i},, {y the y}_{j j})) - - \overset{&OverBar; &OverBar;}{f f},,

In the formula, G _x represents the partial derivative of G for x _i , G _y represents the partial derivative of G for y _j , g _x represents the partial derivative of g( _xi +u, y _j +v) for x _i , g _y represents g(x _i +u,y _j +v) finds the partial derivative of yj,

express

Take the partial derivative of x _i ,

express

Find the partial derivative for y _j , m is the number of iterations.