CN102788558B - Three-dimensional deformation measuring system and three-dimensional deformation measuring method combining speckle correlation and speckle interference - Google Patents

Abstract

The invention relates to a three-dimensional deformation measuring system and a three-dimensional deformation measuring method combining speckle correlation and speckle interference. The system comprises a laser, wherein laser light emitted by the laser passes through a semi-permeable and semi-reflective mirror after being expanded for illuminating a tested object and a reference object surface respectively; the tested object surface and the reference object surface are imaged simultaneously on the target surface of a CCD (Charge Coupled Device) camera through an imaging lens by means of the semi-permeable and semi-reflective mirror; the semi-permeable and semi-reflective mirror is arranged obliquely at an angle of 45 degrees relative to incident rays; and when a reference path exists, object surface speckles and reference surface speckles are interfered with mutually on the target surface of the CCD camera to form an interference speckle image for measuring an off-plane displacement component. A reference substance light path is removed, a speckle image on the object surface is acquired, and two components of in-plane displacement are calculated by using two speckle images acquired before and after deformation. A typical digital speckle light path which is sensitive to the off-plane displacement is utilized, so that the in-plane displacement and speckle interference off-plane displacement of a speckle relevance measuring object are realized, and three-dimensional displacement measurement is realized; and and the system and the method have the advantages of simple light path, and easiness and rapidness for operating and processing data.

Description

Speckle is relevant and speckle interference combines measurement system for three-dimensional deformation and method

Technical field

The present invention relates to a kind of measurement system for three-dimensional deformation and method, relate in particular to a kind of speckle is relevant and speckle interference combines measurement system for three-dimensional deformation and method.

Background technology

The digital speckle correlation method (Digital Speckle Correlation Method, DSCM) being proposed by people such as I Yamaguchi, W.H.Peters and W.F.Ranson has all been shown its applicability and superiority in numerous applications such as the mechanics of materials, fracturing mechanics, biomechanics, existing field real-time measurement, the measurement of microscale deformation field, Electronic Packaging and dynamic displacement and deformation tests.Digital speckle correlation technology is by recording the image before and after deformation of body displacement and the distortion of using certain image correlation searching algorithm to draw object, has that principle is simple, light path simple, noncontact, measurement environment required to the advantages such as low.In recent years, the mathematical theory that some are modern and mathematical method are introduced in the method gradually, and the raising progressively of its measuring accuracy for example uses sub-pix searching algorithm can obtain Displacement.Sub-pix algorithm has a variety of, mainly contains related coefficient fitting process, Newton.Raphson (N-R) process of iteration, method based on gradient etc.Compared with additive method, gradient method have anti-noise ability compared with high, calculated amount is little, precision is compared with advantages of higher, hour more stable in displacement.At present, the field of DSCM application just gradually from the test of conventional material to some new materials tests, from macroscopic field gradually to thin micro-scale, from conventional environment to rugged environment relatively, from laboratory test progressively to engineering site application, from static quasistatic to aspect development such as dynamic standard are dynamic.

Due to the limitation that method itself has, the speckle correlation technique of single beam illumination can only be measured in-plane displacement.Scientific research personnel is just by measuring three-D displacement by DSCM to other measuring techniques combinations or by the relevant method of three-dimensional speckle.DSCM is combined with stereoscopic photograph technology or binocular measuring technique, can measure 3-D displacement field.The stereoscopic photography that for example professor Yao Xuefeng of Tsing-Hua University proposes combines with Digital Speckle Correlation Method for studying 3 D deformation field; Binocular 3-dimensional digital speckle measurement of correlation 3 D deformation and 3 d shape technology that Xie Hui people professor proposes.DSCM is combined with pin hole camera technique, and professor He little Yuan of Southeast China University has proposed relevant the combining with pinhole camera imaging model of digital picture and has measured three-dimensional body displacement method.By the relevant method of three-dimensional speckle, the little flat academician of Chinese University of Science and Technology 5, professor Hu little Fang etc. utilize simulated experiment to obtain interior of articles 3-D displacement field.

Utilize electronic speckle pattern interferometry (ESPI) method can measure the three-D displacement of object, there is noncontact, measurement of full field, the advantage that precision is high.Electronic speckle pattern interferometry technology produces speckle interference based on reference light and object light and measures on CCD target surface.Therefore, three-dimensional speckle is interfered often light path more complicated.Complicated light path has increased measuring system instability, has reduced measuring accuracy.

DSCM is combined with speckle interference, also can measure 3-D displacement field.Professor Zhang Qingchuan adopts two cover light paths, to the positive speckle measurement of correlation that adopts of test specimen, adopts speckle interference to measure to the reverse side of test specimen, has realized three-D displacement field measurement.The method is that the different surfaces of test specimen is measured, and is not the 3 D deformation on same surface.Professors Zhou Canlin etc. combine and measure distortion with electronic speckle pattern interferometry relevant speckle, what adopt is typical speckle relevant light paths, first speckle interference image speckle interference four-step phase-shifting being gathered is processed, then the image of processing is carried out to speckle correlation computations, thereby obtain 3 D deformation field.Principle used is very complicated, image processing process is also very complicated, while utilizing speckle correlation computations in-plane displacement, not directly to obtain required speckle pattern, but obtained through processing by the phase shifted images gathering before and after distortion, in practical operation, be difficult to obtain the numerical value of 3 D deformation field.

Summary of the invention

Object of the present invention is exactly in order to address the above problem, a kind of speckle is relevant and speckle interference combines measurement system for three-dimensional deformation and method are provided, it utilizes the typical Michelson speckle light path to acoplanarity displacement sensitivity, by controlling the reference light in light path, realize in-plane displacement and the speckle interference of speckle measurement of correlation object and measure acoplanarity displacement, realized three-D displacement measurement, the method has advantages of that light path is simple, operation and data processing simple and fast.

To achieve these goals, the present invention adopts following technical scheme:

The measurement system for three-dimensional deformation that speckle is relevant and speckle interference combines, the laser that laser instrument sends is sent into beam expanding lens; Beam expanding lens rear is provided with the semi-transparent semi-reflecting lens of placing with incident ray overturning angle at 45 °, and the reflected light of semi-transparent semi-reflecting lens is irradiated to measured object, and transmitted light is irradiated to reference to object plane, connects and composes reference phase shift light path with reference to object plane and PZT phase-shifter; The speckle image of measured object is imaged on ccd video camera by imaging len through semi-transparent semi-reflecting lens, utilizes two width speckle patterns of measured object distortion front and back, calculates two components of in-plane displacement; In the time that reference path is worked, the speckle image on measured object surface forms and interferes speckle image with the speckle image with reference to object plane, and is imaged on ccd video camera by imaging len, measures object acoplanarity displacement component.

A measuring method that adopts the relevant and measurement system for three-dimensional deformation that speckle interference combines of speckle, it,, by controlling reference path, combines by relevant digital speckle and speckle interference the 3 D deformation of measuring object; Detailed process is: first in the time of the reference laser without reference path, gather the speckle pattern before a width measured object distortion; Then add the reference laser of reference path to realize speckle interference; Loading makes measured object distortion, measures measured object acoplanarity displacement in conjunction with phase-shifting technique; Finally remove reference laser and gather again the speckle pattern after a width measured object distortion; Speckle pattern before and after measured object distortion is carried out to speckle related operation, obtain two-dimensional surface intrinsic displacement component, measure thereby realize 3 D deformation.

Concrete steps of the present invention are:

Step 1: the reflected light with reference to object plane forms reference light; When without reference light, utilize CCD to gather the speckle pattern before measured object distortion;

Step 2: add the reference light of reference path, realize digital speckle interference;

Step 3: load and make measured object distortion, in conjunction with four-step phase-shifting commercial measurement measured object acoplanarity displacement w field;

Step 4: remove reference light; Utilize CCD to gather the speckle pattern after measured object distortion;

Step 5: the speckle pattern after the speckle pattern before the measured object distortion of integrating step one and the measured object distortion of step 4, speckle pattern before and after measured object distortion is carried out to speckle related operation, obtain two-dimensional surface intrinsic displacement component u, v field.

In described step 3, acoplanarity displacement is the displacement w field perpendicular to body surface direction, and concrete measuring process is:

Change the relation between deformation of body according to phase of light wave:

Wherein, λ is sharp light wavelength used, and θ is the angle of illumination light and body surface normal, and w is the acoplanarity displacement of deformation of body, and u is the interior horizontal direction displacement of the face of deformation of body; Known, in the time of illumination light incident angle θ=0, have by formula (4):

Adopt existing phase-shifting technique, calculate deformation of body phase place and then draw acoplanarity displacement w field.

The concrete steps of described step 5 are: described two-dimensional surface intrinsic displacement component is horizontal direction displacement component u and vertical direction displacement component v, and speckle correlation computations is utilized formula (1),

$C(u,v)=\frac{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}[f(x_i,y_i)-\stackrel{\‾}{f}][g(x_i+u,y_j+v)-\stackrel{\‾}{g}]}{\sqrt{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}{[f(x_i,y_j)-\stackrel{\‾}{f}]}^2}\sqrt{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}{[g(x_i+u,y_j+v)-\stackrel{\‾}{g}]}^2}}---\left(1\right)$

Wherein, f (x, y) is the image before being out of shape, (x _i, y _j) be any one displacement point in image before distortion, and g (x ', y ') be the image after distortion, displacement point (x in the corresponding original image of u, v difference, y) the whole pixel displacement of corresponding point in the image after distortion (x ', y '), (x _i+ u, y _j+ v) be displacement point (x _i, y _j) in x _iu and y are moved _jmove the displacement point in the image after the distortion that v obtains, with for image subsection average gray;

In order to improve measuring accuracy, the calculating that utilizes gradient algorithm further to carry out Displacement on the basis of formula (1) solves, the selected Calculation of correlation factor formula of gradient method be formula (1) square, i.e. formula (2);

$C(u,v)=\frac{{\left\{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}\right[f(x_i,y_j)-\stackrel{\‾}{f}\left]\right[g(x_i+u+\mathrm{\Δu},y_j+v+\mathrm{\Δv})-\stackrel{\‾}{g}\left]\right\}}^2}{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}{[f(x_i,y_j)-\stackrel{\‾}{f}]}^2\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}{[g(x_i+u+\mathrm{\Δu},y_j+v+\mathrm{\Δv})-\stackrel{\‾}{g}]}^2}---\left(2\right)$

Wherein, Δ u, Δ v are the Displacement corresponding to whole pixel displacement result, (x _i+ u+ Δ u, y _j+ v+ Δ is v) displacement point (x _i, y _j) in x _iu+ Δ u and y are moved _jmove the displacement point in the image after the distortion that v+ Δ v obtains;

Will taylor expansion, gets first approximation, and order through deriving:

$\left[\begin{array}{c}\mathrm{\Δu}\\ \mathrm{\Δv}\end{array}\right]={\left[\begin{array}{cc}B& C\\ E& H\end{array}\right]}^{-1}\left[\begin{array}{c}A\\ D\end{array}\right]---\left(3\right)$

Wherein

$A=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG}\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_x-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_x\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}^2,$

$B=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_x\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_x-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G_x}^2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG},$

$C=2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_x\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_y-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_x\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_y-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}_x{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG},$

$D=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG}\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_y-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}^2,$

$E=2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_x-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_x-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}_x{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG},$

$H=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_y-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}_y^2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG},$

$G=g(x_i+u,y_j+v)-\stackrel{\‾}{g},$

$G_x=g_x-{\stackrel{\‾}{g}}_x,G_y=g_y-{\stackrel{\‾}{g}}_y,$

$F=f(x_i,y_j)-\stackrel{\‾}{f},$

In formula, G _xrepresent that G is to x _iask local derviation, G _yrepresent that G is to y _jask local derviation, g _xrepresent g (x _i+ u, y _j+ v) to x _iask local derviation, g _yrepresent g (x _i+ u, y _j+ v) to y _jask local derviation, represent to x _iask local derviation, represent to y _jask local derviation, m is iterations.

Beneficial effect of the present invention: utilize the typical digital speckle interference light path to acoplanarity displacement sensitivity, by controlling the reference light in light path, realized in-plane displacement and the speckle interference of speckle measurement of correlation object and measured acoplanarity displacement, realized three-D displacement measurement.The method has advantages of that light path is simple, operation and data processing simple and fast.

Brief description of the drawings

Fig. 1 is optical measuring system figure;

Fig. 2 is the speckle image while not being out of shape;

Fig. 3 be distortion after from face interfere bar;

Fig. 4 is the speckle image after distortion;

Fig. 5 is the three-D displacement component after deformation of body, horizontal direction u field pattern;

Fig. 6 is the three-D displacement component after deformation of body, vertical direction v field pattern;

Fig. 7 is the three-D displacement component after deformation of body, acoplanarity displacement w field pattern;

Fig. 8 is process flow diagram of the present invention.

Wherein, 1. laser instrument, 2. beam expanding lens, 3. semi-transparent semi-reflecting lens, 4. measured object, 5. with reference to object plane, 6.PZT phase-shifter, 7. imaging len, 8.CCD video camera.

Embodiment

Below in conjunction with accompanying drawing and embodiment, the invention will be further described.

In Fig. 1, the measurement system for three-dimensional deformation that a kind of speckle is relevant and speckle interference combines, it comprises the speckle relevant light paths of measuring object plane internal strain component and the speckle interference phase shift light path of measuring acoplanarity displacement component; After the laser beam expanding that laser instrument 1 sends by throw light on respectively tested object plane 4 and with reference to object plane 5 of semi-transparent semi-reflecting lens 3.Semi-transparent semi-reflecting lens 3 is placed with incident light overturning angle at 45 °.The reflected light of object plane 4 sees through semi-transparent semi-reflecting lens 3, reflects on semi-transparent semi-reflecting lens 3 with reference to the reflected light of object plane 5, and two bundle light process imaging len 7 post-concentrations are on ccd video camera 8.

As shown in Figure 1, test specimen is organic glass free beam to experiment light path, long 150.0mm, high 19.5mm, thick 18.5mm.Be coated with water paint on free beam surface, to strengthen its reflectivity, whole experimental provision is placed on anti-vibration platform and carries out.With He-Ne laser instrument 1, as light source, light beam is radiated on free beam surface after beam expanding lens 2 expands.By semi-transparent semi-reflecting lens 3(BS) the another light beam that separates is as with reference to light.When experiment, process flow diagram as shown in Figure 8, the speckle image when first blocking reference light and gathering a width free beam and be not out of shape, as shown in Figure 2; Then add reference light, realize electronic speckle pattern interferometry; Gather object speckle interference image and subtract each other in real time, during this time free beam being loaded, can observe object acoplanarity displacement striped, as shown in Figure 3; Use 6 realizations of PZT phase-shifter wait phase shift and gather speckle interference fringe pattern; Finally, block reference light, again gather the speckle image after free beam distortion, as shown in Figure 4.

Described two-dimensional surface intrinsic displacement component is: utilize formula (1)

$C(u,v)=\frac{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}[f(x_i,y_i)-\stackrel{\‾}{f}][g(x_i+u,y_j+v)-\stackrel{\‾}{g}]}{\sqrt{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}{[f(x_i,y_j)-\stackrel{\‾}{f}]}^2}\sqrt{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}{[g(x_i+u,y_j+v)-\stackrel{\‾}{g}]}^2}}---\left(1\right)$

Wherein, f (x, y) is the image before being out of shape, (x _i, y _j) be any one displacement point in image before distortion, and g (x ', y ') be the image after distortion, displacement point (x in the corresponding original image of u, v difference, y) the whole pixel displacement of corresponding point in the image after distortion (x ', y '), (x _i+ u, y _j+ v) be displacement point (x _i, y _j) in x _iu and y are moved _jmove the displacement point in the image after the distortion that v obtains, with for image subsection average gray;

In order to improve measuring accuracy, on the basis of formula (1), utilize existing gradient method further to carry out the calculating of Displacement, the selected Calculation of correlation factor formula of gradient method be formula (1) square, i.e. formula (2)

$C(u,v)=\frac{{\left\{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}\right[f(x_i,y_j)-\stackrel{\‾}{f}\left]\right[g(x_i+u+\mathrm{\Δu},y_j+v+\mathrm{\Δv})-\stackrel{\‾}{g}\left]\right\}}^2}{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}{[f(x_i,y_j)-\stackrel{\‾}{f}]}^2\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}{[g(x_i+u+\mathrm{\Δu},y_j+v+\mathrm{\Δv})-\stackrel{\‾}{g}]}^2}---\left(2\right)$

Wherein, Δ u, Δ v are the Displacement corresponding to whole pixel displacement result;

Will taylor expansion, gets first approximation, and order through deriving:

$\left[\begin{array}{c}\mathrm{\Δu}\\ \mathrm{\Δv}\end{array}\right]={\left[\begin{array}{cc}B& C\\ E& H\end{array}\right]}^{-1}\left[\begin{array}{c}A\\ D\end{array}\right]---\left(3\right)$

Wherein

$A=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG}\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_x-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_x\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}^2,$

$B=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_x\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_x-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G_x}^2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG},$

$C=2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_x\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_y-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_x\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_y-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}_x{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG},$

$D=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG}\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_y-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}^2,$

$E=2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_x-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_x-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}_x{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG},$

$H=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_y-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}_y^2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG}.$

$G(x_i,y_j)=g(x_i+u,y_j+v)-\stackrel{\‾}{g},$

$G_x=g_x-{\stackrel{\‾}{g}}_x,G_y=g_y-{\stackrel{\‾}{g}}_y,$

$F(x_i,y_i)=f(x_i,y_j)-\stackrel{\‾}{f},$

In formula, G _xrepresent that G is to x _iask local derviation, G _yrepresent that G is to y _jask local derviation, g _xrepresent g (x _i+ u, y _j+ v) to x _iask local derviation, g _yrepresent g (x _i+ u, y _j+ v) to y _jask local derviation, represent to x _iask local derviation, represent to y _jask local derviation, m is iterations.

Described off-surface displacement measurement process is:

Phase of light wave changes with the phase relation of deformation of body:

Wherein, λ is sharp light wavelength used, and θ is the angle of illumination light and body surface normal, and w is the acoplanarity displacement of deformation of body, and u is the interior horizontal direction displacement of the face of deformation of body; Known by formula (4), approximate in the time that illumination light incident angle θ is less than 5 ° to regard change in optical path length as only relevant with acoplanarity displacement w, by formula (4):

Adopt phase-shifting technique to calculate deformation of body phase place and then draw w field.

Before and after distortion, speckle image (Fig. 2 and Fig. 4) is for speckle correlation computations in-plane displacement u field and v field (unit: pixel).Adopt existing phase-shifting technique to process speckle interference fringe pattern, can obtain acoplanarity displacement w field (unit: micron).Variable shaped beam 3 D deformation component experimental result is as shown in Fig. 5, Fig. 6, Fig. 7.

Experimental result shows, utilizes speckle method relevant and that speckle interference combines can measure fast and effectively object dimensional distortion, has that light path is simple to operation, the simple advantage of data processing.Experimental result v, w field and document [Sun Ping, Fan Xiangju, Wang Xinghai. based on the three-dimensional carrier frequency electronic speckle interference technique [J] of large-misplacement square glass prism. Acta Optica, 2011,31 (4): 0412012] in result coincide better, u field is substantially identical.

By reference to the accompanying drawings the specific embodiment of the present invention is described although above-mentioned; but not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technical scheme of the present invention, those skilled in the art do not need to pay various amendments that creative work can make or distortion still in protection scope of the present invention.

Claims (2)

1. a measuring method for the relevant and measurement system for three-dimensional deformation that speckle interference combines of speckle, is characterized in that,

Described speckle measurement system for three-dimensional deformation relevant and that speckle interference combines comprises:

The laser that laser instrument sends is sent into beam expanding lens; Beam expanding lens rear is provided with the semi-transparent semi-reflecting lens of placing with incident ray overturning angle at 45 °, and the reflected light of semi-transparent semi-reflecting lens is irradiated to measured object, and transmitted light is irradiated to reference to object plane, connects and composes reference path with reference to object plane and PZT phase-shifter; The speckle image of measured object is imaged on ccd video camera by imaging len through semi-transparent semi-reflecting lens, utilizes two width speckle patterns of measured object distortion front and back, calculates two components of in-plane displacement; In the time that reference path is worked, the speckle image on measured object surface forms and interferes speckle image with the speckle image with reference to object plane, and is imaged on ccd video camera by imaging len, measures object acoplanarity displacement component;

The concrete grammar of described system is:

It,, by controlling reference path, combines by relevant digital speckle and speckle interference the 3 D deformation of measuring object; Detailed process is: first in the time of the reference laser without reference path, gather the speckle pattern before a width measured object distortion; Then add the reference laser of reference path to realize speckle interference; Loading makes measured object distortion, measures the acoplanarity displacement of measured object in conjunction with phase-shifting technique; Finally remove reference laser and gather again the speckle pattern after a width measured object distortion; Speckle pattern before and after measured object distortion is carried out to speckle related operation, obtain two-dimensional surface intrinsic displacement component, measure thereby realize 3 D deformation;

Concrete steps are: step 1: the reflected light with reference to object plane forms reference light; When without reference light, utilize CCD to gather the speckle pattern before measured object distortion; Step 2: add the reference light of reference path, realize digital speckle interference; Step 3: load and make measured object distortion, in conjunction with four-step phase-shifting commercial measurement measured object acoplanarity displacement w field; Step 4: remove reference light; Utilize CCD to gather the speckle pattern after measured object distortion; Step 5: the speckle pattern after the speckle pattern before the measured object distortion of integrating step one and the measured object distortion of step 4, speckle pattern before and after measured object distortion is carried out to speckle related operation, obtain two-dimensional surface intrinsic displacement component u, v field;

The concrete steps of described step 5 are: described two-dimensional surface intrinsic displacement component is horizontal direction displacement component u and vertical direction displacement component v, and speckle correlation computations is utilized formula (1),

$C(u,v)=\frac{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}[f(x_i,y_j)-\stackrel{\‾}{f}][g(x_i+u,y_j+v)-\stackrel{\‾}{g}]}{\sqrt{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}{[f(x_i,y_j)-\stackrel{\‾}{f}]}^2}\sqrt{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}{[g(x_i+u,y_j+v)-\stackrel{\‾}{g}]}^2}}---\left(1\right)$

Wherein, f (x, y) is the image before being out of shape, (x _i, y _j) be any one displacement point in image before distortion, and g (x ', y ') be the image after distortion, displacement point (x in the corresponding original image of u, v difference, y) the whole pixel displacement of corresponding point in the image after distortion (x ', y '), (x _i+ u, y _j+ v) be displacement point (x _i, y _j) in x _iu and y are moved _jmove the displacement point in the image after the distortion that v obtains, with for image subsection average gray;

In order to improve measuring accuracy, the calculating that utilizes existing gradient algorithm to carry out Displacement on the basis of formula (1) solves, the selected Calculation of correlation factor formula of gradient method be formula (1) square, i.e. formula (2);

$C(u,v)=\frac{\left\{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}\right[f(x_i,y_j)-\stackrel{\‾}{f}\left]\right[g(x_i+u+\mathrm{\Δu},y_j+v+\mathrm{\Δv})-\stackrel{\‾}{g}]{\}}^2}{\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}{[f(x_i,y_j)-\stackrel{\‾}{f}]}^2\underset{i}{\overset{m}{\mathrm{\Σ}}}\underset{j}{\overset{m}{\mathrm{\Σ}}}{[g(x_i+u+\mathrm{\Δu},y_j+v+\mathrm{\Δv})-\stackrel{\‾}{g}]}^2}---\left(2\right)$

Wherein, Δ u, Δ v are the Displacement corresponding to whole pixel displacement result;

Will $g(x_i+u+\mathrm{\Δu},y_j+v+\mathrm{\Δv})-\stackrel{\‾}{g}$ Taylor expansion, gets first approximation, and order $\frac{\∂C}{\∂\mathrm{\Δu}}=0,\frac{\∂C}{\∂\mathrm{\Δv}}=0;$ Can obtain through deriving:

$\left[\begin{array}{c}\mathrm{\Δu}\\ \mathrm{\Δv}\end{array}\right]={\left[\begin{array}{cc}B& C\\ E& H\end{array}\right]}^{-1}\left[\begin{array}{c}A\\ D\end{array}\right]---\left(3\right)$

Wherein

$A=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG}\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}G{G}_x-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}F{G}_x\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}^2,$

$B=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{FG}}_x\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{GG}}_x-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G_x}^2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG},$

$C=2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{FG}}_x\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{GG}}_y-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{GG}}_x\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{FG}}_y-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}_x{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG},$

$D=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG}\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{GG}}_y-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{FG}}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}^2,$

$E=2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{FG}}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{GG}}_x-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{GG}}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{FG}}_x-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}_x{G}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG},$

$H=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{FG}}_y\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{GG}}_y-\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{G}_y^2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{FG}.$

$G(x_i,y_j)=g(x_i+u,y_j+v)-\stackrel{\‾}{g},$

$G_x=g_x-{\stackrel{\‾}{g}}_x,G_y=g_y-{\stackrel{\‾}{g}}_y,$

$F(x_i,y_j)=f(x_i,y_j)-\stackrel{\‾}{f},$

In formula, G _xrepresent that G is to x _iask local derviation, G _yrepresent that G is to y _jask local derviation, g _xrepresent g (x _i+ u, y _j+ v) xi being asked to local derviation, gy represents g (x _i+ u, y _j+ v) to y _jask local derviation, g _xrepresent xi is asked to local derviation, represent to y _jask local derviation, m is iterations.

2. the measuring method of the relevant and measurement system for three-dimensional deformation that speckle interference combines of speckle as claimed in claim 1, it is characterized in that, in described step 3, acoplanarity displacement is to be perpendicular to the concrete measuring process in displacement w field of body surface direction: the phase relation according to phase of light wave variation with deformation of body:

Wherein, λ is sharp light wavelength used, and θ is the angle of illumination light and body surface normal, and w is the acoplanarity displacement of deformation of body, and u is the interior horizontal direction displacement of the face of deformation of body; Known, in the time of illumination light incident angle θ=0, have by formula (4):

Adopt existing phase-shifting technique, calculate deformation of body phase place and then draw w field.