CN110823117A - A single-step phase-shift electron speckle interferometry method, system, device and storage medium - Google Patents

Abstract

The invention discloses a single-step phase-shift electronic speckle interferometry method, system, device and storage medium. The measurement method adds the concept of interpolation calculation on the basis of traditional phase-shift electronic speckle interferometry. Through the method of interpolation calculation, multiple phase-shift images required before the deformation of the object to be measured and multiple phase-shift images required after the object is deformed are obtained, instead of the multiple phase-shift images before and after the deformation of the object collected one by one in the traditional measurement method. Phase-shifted images, eliminating the need for multiple phase-shifted images before and after the object is deformed, thereby solving the problem that the existing phase-shifting electronic speckle interferometry can only be used in static or quasi-static measurement, and realizing dynamic measurement; and , the patent of the present invention does not need to increase the use of additional optical equipment or arrangement, and only needs to use the traditional phase-shift electronic speckle interferometry device to realize dynamic measurement. The present invention can be applied to the technical field of optical measurement.

Description

A single-step phase-shift electron speckle interferometry method, system, device and storage medium

technical field

The invention relates to the field of optical measurement, in particular to a method, system, device and storage medium for single-step phase-shift electron speckle interferometry.

Background technique

Electron Speckle Interferometry (ESPI) is widely used in material elastic modulus measurement, surface roughness evaluation, stress-strain analysis, vibration analysis and non-destructive testing. Electron speckle interferometry is a commonly used optical experimental technique for full-field surface displacement measurements ranging from tens of nanometers to several microns. This full-field measurement has a wide range of practical applications, including mechanical Stress assessment, study of vibration modes of mechanical components, quality testing of MEMS and health monitoring of biological samples.

Electron speckle interferometry obtains the information to be measured by recording the interference pattern observed on an optically rough surface. A common approach is to use four images obtained with a four-step phase shift before the object is deformed, and another four images obtained with a four-step phase shift after the deformation; Analysis of the intensity changes within the phase-shifted image enables the determination of the phase changes and thus the surface displacements at the corresponding pixels.

The existing technology of electronic speckle interferometry usually needs to collect multiple sets of speckle images before and after the deformation of the measured object. Used in static measurements. If the surface moves significantly during image acquisition, a phase change occurs in addition to the phase change caused by the phase shift. Vibration and dynamic motion can be measured based on methods such as multiple wavelengths, frequency sweeps, or the use of multi-camera systems, but these methods require complex and expensive optical arrangements.

SUMMARY OF THE INVENTION

In order to solve at least one of the above technical problems, the purpose of the present invention is to provide a single-step phase-shift electron speckle interferometry method, system, device and medium.

The technical solution adopted in the present invention is: on the one hand, the embodiment of the present invention includes a single-step phase-shift electronic speckle interferometry method, including:

Collect the electronic speckle image of the measured object;

extracting a first phase shift image from the electronic speckle image acquired at the first moment;

extracting a second phase-shift image from the electronic speckle image acquired at the second moment;

performing interpolation calculation on the first phase-shift image and the second phase-shift image;

generating at least one sub-image of the first phase-shift image according to the result of the interpolation calculation;

generating at least one sub-image of the second phase-shift image according to the result of the interpolation calculation;

Analyzing the first phase-shift image, the sub-image of the first phase-shift image, the second phase-shift image and the sub-image of the second phase-shift image, and calculating and extracting the phase difference between the first moment and the second moment; The phase difference is used to describe the change of the surface displacement of the measured object.

Further, the step of performing interpolation calculation on the first phase-shift image and the second phase-shift image specifically includes:

A pre-phase-shift image group and a post-phase-shift image group are extracted from the electronic speckle image; the pre-phase-shift image group includes a plurality of phase-shift images extracted before the target phase-shift image, and the post-phase-shift image The group includes a plurality of phase-shift images extracted after the target phase-shift image; the target phase-shift images are respectively a first phase-shift image and a second phase-shift image;

Interpolation calculation is performed using the extracted pre-phase-shift image group and the post-phase-shift image group.

Further, the interpolation calculation is performed by the following formula:

In the formula, I _n2 , I _n3 , and I _n4 are respectively the sub-images of the target phase-shift image, and I _n-6 , I _n-5 , I _n-3 , I _n-2 , and I _n-1 form the Front phase-shift image group; In ₊₁ , In ₊₂ , In ₊₃ , In ₊₅ , In ₊₆ form the post-phase-shift image group.

Further, a single-step phase-shift electron speckle interferometry method further includes:

Collect electronic speckle images of the measured object at multiple times;

The electronic speckle images at any first moment and second moment are processed according to the single-step electronic speckle interferometry method to output the phase difference between the first moment and the second moment; the phase difference is used to describe the measured object change in surface displacement.

On the other hand, the embodiment of the present invention also includes a single-step phase-shift electronic speckle interferometry system, including:

The acquisition module is used to acquire the electronic speckle image of the measured object;

an extraction module, configured to extract a first phase shift image from the electronic speckle image acquired at the first moment, and extract a second phase shift image from the electronic speckle image acquired at the second moment image;

a calculation module for performing interpolation calculation on the first phase-shift image and the second phase-shift image;

a generating module for generating at least one sub-image of the first phase-shifted image according to the result of the interpolation calculation; and generating at least one sub-image of the second phase-shifted image;

The processing module is used for analyzing the first phase-shift image, the sub-image of the first phase-shift image, the second phase-shift image and the sub-image of the second phase-shift image, and calculating and extracting the difference between the first moment and the second moment. The phase difference between; the phase difference is used to describe the change of the surface displacement of the measured object;

The output module is used to output the extracted phase difference.

Further, the computing module includes:

The extraction unit is used for extracting a pre-phase-shift image group and a post-phase-shift image group from the collected electronic speckle images of the measured object, the pre-phase-shift image group including a plurality of images extracted before the target phase-shift image a phase-shift image, the post-phase-shift image group includes a plurality of phase-shift images extracted after the target phase-shift image; the target phase-shift images are respectively a first phase-shift image and a second phase-shift image;

A calculation unit, configured to perform interpolation calculation by using the pre-phase-shift image group and the post-phase-shift image group obtained by extraction.

Further, the processing module includes:

an analysis unit, configured to analyze the first phase-shift image, the sub-image of the first phase-shift image, the second phase-shift image at the second moment, and the sub-image of the second phase-shift image;

a calculation unit for calculating the phase difference between the first moment and the second moment;

The extraction unit is used to extract the calculated phase difference.

On the other hand, the embodiment of the present invention also includes a single-step phase-shift electronic speckle interferometry device, including: a laser, a camera and a computer, wherein the laser is used to irradiate the measured object to generate an electronic speckle image; The camera is used for collecting electronic speckle images; the computer is used for executing a single-step phase-shifting electronic speckle interferometry method to process the collected electronic speckle images.

On the other hand, an embodiment of the present invention further includes a storage medium, in which processor-executable instructions are stored, and when executed by the processor, the processor-executable instructions are used to perform single-step phase-shift electronic speckle interferometry Measurement methods.

The beneficial effects of the present invention are as follows: a single-step phase-shift electronic speckle interferometry method is proposed in the embodiment, wherein the interpolation calculation method is mainly used to obtain multiple phase-shift images required for measurement, instead of one by one in the existing measurement method. A plurality of phase-shifted images collected; thus solving the problem that the existing phase-shifting electronic speckle interferometry can only be used in static or quasi-static measurement, and realizing dynamic measurement; and the patent of the present invention does not require additional optical equipment or Arrangement, dynamic measurement can be achieved only by using the traditional phase-shift electronic speckle interferometry device.

Description of drawings

Fig. 1 is the step flow chart of the single-step phase-shift electron speckle interferometry method described in the embodiment of the present invention;

2 is a structural block diagram of the single-step phase-shift electronic speckle interferometry system described in the embodiment of the present invention;

FIG. 3 is the distribution of four phase shift maps at each moment obtained by interpolation calculation according to the embodiment of the present invention.

Detailed ways

The existing phase-shift electron speckle interferometry methods are as follows:

The light intensity I at each pixel within the measured image can be expressed as:

I=A+Bcosφ,

Where A is the background light intensity, B is the modulation degree, and φ is the random phase.

可以表达为：Phase-shifted electron speckle interferometry on a static object or quasi-static method is to collect four phase-shifted images before the object is deformed, and the phase-shift step size is

can be expressed as:

I ₀₁ =A+Bcosφ

I ₀₃ =A+Bcos(φ+π)

In the formula, 0 in the subscripts 01, 02, 03, and 04 represents a certain moment before the object is deformed, and the number is 0, and 1, 2, 3, and 4 in the subscripts 01, 02, 03, and 04 represent the object before deformation. The first, second, third, and fourth phase-shift images at a certain moment, the four phase-shift images are all acquired by the phase-shift electron speckle interferometry method.

Then four additional phase-shifted images are acquired after the deformation of the object of interest occurs, which can be expressed as:

I ₁₁ =A+Bcos(φ+Δ)

I ₁₃ =A+Bcos(φ+Δ+π)

In the formula, 1 in the subscripts 11, 12, 13, and 14 indicates a certain moment after the object is deformed, and the number is 1, and 1, 2, 3, and 4 in the subscripts 11, 12, 13, and 14 indicate that the object is deformed. The first, second, third, and fourth phase-shift images at a certain moment, the four phase-shift images are also acquired by the phase-shift electron speckle interferometry method.

where Δ can be solved by the following equation:

In the formula, Δ is the phase difference between the object before and after the object is deformed, and the phase difference can be used to describe the change of the surface displacement of the measured object, I ₀₁ , I ₀₂ , I ₀₃ , I ₀₄ , I ₁₁ , I ₁₂ , I ₁₃ , and I ₁₄ are the acquired four phase-shift images before the object is deformed and the four phase-shift images after the object is deformed, respectively.

When the four phase-shifted images are collected before and after the deformation of the object, the object must be in a static or quasi-static state, which limits the existing phase-shifted electron speckle interferometry methods to only be used for static measurement.

Example 1

As shown in Figure 1, a single-step phase-shift electron speckle interferometry method specifically includes the following steps:

S1. Collect the electronic speckle image of the measured object;

S2. Extract a first phase shift image from the electronic speckle image collected at the first moment;

S3. Extract a second phase-shift image from the electronic speckle image acquired at the second moment;

S4. Interpolate the first phase-shift image and the second phase-shift image;

S5. generate at least one sub-image of the first phase-shift image according to the result of the interpolation calculation;

S6. generate at least one sub-image of the second phase-shift image according to the result of the interpolation calculation;

S7. Analyze the first phase-shift image, the sub-image of the first phase-shift image, the second phase-shift image and the sub-image of the second phase-shift image, calculate and extract the phase between the first moment and the second moment difference; the phase difference is used to describe the change of the surface displacement of the measured object.

As a preferred implementation of the embodiment of the measurement method, the step S4, that is, the step of performing interpolation calculation on the first phase-shift image and the second phase-shift image, specifically includes:

S401. Extract a pre-phase-shift image group and a post-phase-shift image group from the electronic speckle image; the pre-phase-shift image group includes a plurality of phase-shift images extracted before the target phase-shift image, and the post-phase-shift image group The shift image group includes a plurality of phase shift images extracted after the target phase shift image; the target phase shift images are respectively a first phase shift image and a second phase shift image;

S402. Perform interpolation calculation by using the pre-phase-shift image group and the post-phase-shift image group obtained by extraction.

As a preferred implementation of the embodiment of the measurement method, the interpolation calculation in step S402 is performed by the following formula:

In the formula, I _n2 , I _n3 , I _n4 are respectively the sub-images of the target phase-shift image, and the target phase-shift image is the first phase-shift image and the second phase-shift image respectively; I _n-6 , I _{n -5} , I _n-3 , I _n-2 , I _n-1 form the pre-phase shift image group; I _n+1 , I _n+2 , I _n+3 , I _n+5 , I _n+6 The post-phase-shift image group is composed. For example, when the extracted first phase-shift image is I ₇₁ , then I ₇₂ , I ₇₃ , and I ₇₄ are respectively the sub-images of the first phase-shift image obtained by interpolation calculation, I ₁ , I ₂ , I ₃ , and I ₄ . , I ₅ , I ₆ form the front phase-shift image group, that is, the first six phase-shift images of the first phase-shift image, and I ₈ , I ₉ , I ₁₀ , I ₁₁ , I ₁₂ , I ₁₃ form the back The phase-shifted image group, that is, the last six phase-shifted images of the first phase-shifted image; and when the extracted second phase-shifted image is I ₈₁ , then I ₈₂ , I ₈₃ , and I ₈₄ are respectively the second phase-shifted images obtained by interpolation. The sub-images of the phase-shift image, I ₂ , I ₃ , I ₄ , I ₅ , I ₆ , and I ₇ form the pre-phase-shift image group, that is, the first six phase-shift images of the second phase-shift image, I ₉ , I ₁₀ , I ₁₁ , I ₁₂ , I ₁₃ , and I ₁₄ form the post-phase-shift image group, that is, the post-phase-shift images of the second phase-shift image.

的方式，使用摄像机连续采图；即如果采集的第一时刻图像相位步长为0，则第二时刻图像相位步长为

第三时刻图像相位步长为π，第四时刻图像相位步长为

第五时刻图像相位步长为0，第六时刻图像相位步长为

以后依次类推。In this embodiment, the step S1, that is, the step of collecting the electronic speckle image of the measured object specifically includes: using a traditional phase-shift electronic speckle interferometry device to generate and collect the electronic speckle image, wherein the acquisition method is: Use the phase shift between images to keep increasing

The way of using the camera to continuously capture images; that is, if the phase step of the image at the first moment of acquisition is 0, the phase step of the image at the second moment is

The image phase step size at the third moment is π, and the image phase step size at the fourth moment is

The image phase step size at the fifth moment is 0, and the image phase step size at the sixth moment is

And so on.

In this embodiment, only one phase-shift image, ie, the first phase-shift image, needs to be collected before the object is deformed, and the other three images can be obtained by interpolation. Similarly, only another phase-shift image, ie, the second phase-shift image, needs to be acquired after the deformation of interest occurs, and the remaining three images can also be calculated by interpolation.

In this embodiment, in the step of performing interpolation calculation on the first phase-shift image in step S4, it is necessary to first extract the pre-phase-shift image group and the post-phase-shift image group; the pre-phase-shift image group is included in the target phase-shift image group. Multiple phase-shift images extracted before the image, and the post-phase-shift image group includes multiple phase-shift images extracted after the target phase-shift image; for example, if the first phase-shift image acquired is I ₇₁ , then Before performing the interpolation calculation on the first phase-shift image, it is necessary to extract the pre-phase-shift image group from the electronic speckle image, that is, the 6 phase-shift images before the first phase-shift image, which are respectively expressed as I ₁ , I ₂ , I ₃ , I ₄ , I ₅ , I ₆ , and the post-phase-shift image group needs to be extracted from the electronic speckle image, that is, the 6 phase-shift images after the first phase-shift image, which are I ₈ , I ₉ , I ₁₀ , I ₁₁ , I ₁₂ , I ₁₃ . Then use the interpolation calculation formula to obtain the other three phase-shifted images at the first moment, which are I ₇₂ , I ₇₃ and I ₇₄ respectively. The specific calculation process is as follows:

Similarly, in this embodiment, in the step of performing interpolation calculation on the second phase-shift image in step S4, it is necessary to first extract the pre-phase-shift image group and the post-phase-shift image group; the pre-phase-shift image group includes the The multiple phase-shift images extracted before the target phase-shift image, and the post-phase-shift image group includes multiple phase-shift images extracted after the target phase-shift image; for example, it is assumed that the collected second phase-shift image is I ₈₁ , before performing the interpolation calculation on the second phase-shift image, it is necessary to extract the pre-phase-shift image group from the electronic speckle image, that is, the 6 phase-shift images before the first phase-shift image, respectively denoted as I ₂ , I ₃ , I ₄ , I ₅ , I ₆ , I ₇ , and the post-phase-shift image group needs to be extracted from the electronic speckle image, that is, the 6 phase-shift images after the first phase-shift image, which are respectively I ₉ , I ₁₀ , I ₁₁ , I ₁₂ , I ₁₃ , I ₁₄ . Then, by using the interpolation calculation formula, the other three phase-shift images at the second moment are obtained by calculation, which are I ₈₂ , I ₈₃ and I ₈₄ respectively. The specific calculation process is as follows:

Using the method of interpolation calculation, the four phase-shifted images required to obtain the first moment are I ₇₁ , I ₇₂ , I ₇₃ , and I ₇₄ , respectively, where I ₇₁ is extracted from the collected electron speckle images, and I ₇₂ , I ₇₃ , and I ₇₄ are obtained by interpolation calculation. Similarly, by means of interpolation calculation, the four phase-shifted images required at the second moment can be obtained respectively as I ₈₁ , I ₈₂ , I ₈₃ , and I ₈₄ , wherein I ₈₁ is extracted from the collected electron speckle image, and I ₈₂ , I ₈₃ , and I ₈₄ are calculated by interpolation. Then, using the existing phase-shift electron speckle interferometry method, and using the interpolation calculation method to obtain I ₇₁ , I ₇₂ , I ₇₃ , I ₇₄ , I ₈₁ , I ₈₂ , I ₈₃ , I ₈₄ , the first moment is obtained by calculation and the phase difference at the second moment, the phase difference can be used to describe the change of the surface displacement of the measured object.

To sum up, the single-step phase-shift electron speckle interferometry method described in this embodiment has the following advantages:

By using the interpolation calculation method, multiple phase-shift images required before the deformation of the measured object and multiple phase-shift images required after the object is deformed are obtained, instead of the objects collected one by one in the existing phase-shift electronic speckle interferometry method Multiple phase-shift images before and after the object is deformed, eliminating the need for multiple phase-shift images before and after the object is deformed, thus solving the problem that the existing phase-shift electron speckle interferometry method can only be used in static or quasi-static measurement In addition, the measurement method described in this embodiment is to add the concept of interpolation calculation on the basis of the existing phase-shift electronic speckle interferometry, so there is no need to increase the use of additional optical equipment or The arrangement can realize dynamic measurement only by using the existing phase-shift electronic speckle interferometry device, and finally calculate the phase difference, so that the change of the surface displacement of the measured object can be described.

Example 2

A single-step phase-shift electron speckle interferometry method, comprising the following steps:

Collect electron speckle images of the object to be measured at multiple times; for example, collect electron speckle images at one hundred times such as t1, t2...t100.

Select any two of the time t1, t2...t100 as the first time and the second time, extract the phase shift images of the first time and the second time, and execute the single-step phase-shift electronic method described in Embodiment 1. The speckle interferometry method is used to output the phase difference between the first moment and the second moment; the phase difference is used to describe the change of the surface displacement of the measured object. That is, the single-step phase-shift electronic speckle interferometry method described in this embodiment can obtain 4 phase-shift images required at any moment, and calculate the phase difference between any two moments according to actual needs, so that Realize dynamic measurement and obtain the change information of the surface displacement of the measured object.

The single-step phase-shift electron speckle interferometry method described in this embodiment has the following advantages:

By using the method of interpolation calculation, it is possible to obtain multiple phase-shift images required for measurement at any moment, that is, to obtain multiple phase-shift images required before the deformation of the measured object and multiple phase-shift images required after the object is deformed , instead of the multiple phase-shift images before and after the object is deformed, which are collected one by one in the existing phase-shift electronic speckle interferometry method, eliminating the need for multiple phase-shift images in the state before and after the object is deformed, so as to solve the problem of the existing phase-shift images. The problem that the shifting electron speckle interferometry method can only be used in static or quasi-static measurement can realize dynamic measurement; and the measurement method described in this embodiment is based on the existing phase shifting electron speckle interferometry method. The concept of interpolation calculation is added, so there is no need to increase the use of additional optical equipment or arrangements, just use the existing phase-shift electronic speckle interferometry device to achieve dynamic measurement, and finally calculate the phase difference, which can describe the measured Changes in the displacement of the surface of an object.

Example 3

Referring to FIG. 2 , this embodiment includes a single-step phase-shift electronic speckle interferometry system, including an acquisition module, an extraction module, a calculation module, a generation module, a processing module and an output module.

The acquisition module adopts the phase shift amount between the images to keep increasing The electronic speckle image of the object to be measured is obtained by using the camera to continuously capture images; the acquisition module can collect electronic speckle images at multiple times according to actual needs, such as t1, t2...t100, etc. An electronic speckle image at a time, and the acquisition module only needs to collect one electronic speckle image at a certain time. For an electronic speckle image, only one electronic speckle image needs to be collected at the time t3, t4...t100.

The extraction module is used to extract the electronic speckle image required for measurement from the collected electronic speckle image, for example, specifying time t7 as the first time, time t8 as the second time, and extraction at time t7 The collected electron speckle image is the first phase shift image, and the electron speckle image collected at time t8 is extracted as the second phase shift image. The specific operations are as follows:

The acquisition module uses a camera to acquire an electronic speckle image at one hundred times such as t1, t2...t100;

forming the electronic speckle image into a video signal;

connecting the formed video signal to an input of a computer monitor;

The electronic speckle image collected at time t7 is extracted by a computer as the first phase shift image and the electronic speckle image collected at time t8 is extracted as the second phase shift image.

The calculation module is used to perform interpolation calculation on the first phase-shift image and the second phase-shift image, and specifically includes:

Using a computer to analyze the received first phase-shifted image and the second phase-shifted image;

Extract the first six phase-shift images of the first phase-shift image from the collected electron speckle images, that is, extract the electron-speckle images collected at t1, t2, t3, t4, t5, and t6 respectively to form the pre-phase-shift images group, and extract the last six phase-shift images of the first phase-shift image from the collected electronic speckle images, that is, extract the electronic speckle images collected at t8, t9, t10, t11, t12, and t13. Phase shift image group;

Similarly, the first six phase-shift images of the second phase-shift image are extracted from the collected electronic speckle images, that is, the electronic speckle images collected at t2, t3, t4, t5, t6, and t7 are extracted before the composition Phase shift image group, and extract the last 6 phase shift images of the second phase shift image from the collected electron speckle images, namely extract the electron speckle collected at t9, t10, t11, t12, t13, t14 respectively Phase-shifted image group after image composition;

The other three phase-shift images corresponding to the first phase-shift image and the other three phase-shift images corresponding to the second phase-shift image are respectively calculated according to the pre-designed interpolation calculation formula program.

The generating module is used for generating four phase-shift images including the first phase-shift image required at the first moment according to the result of the interpolation calculation; and generating the second phase-shift image required at the second moment including the second phase-shift image of four phase-shifted images.

The processing module is configured to analyze the four phase-shifted images required at the first moment and the four dependent images required at the second moment generated by the generation module, and analyze the four phase-shifted images required at the second moment, and measure them according to a pre-designed existing electronic speckle interferometry method. The calculation formula of the phase difference in the program calculates and extracts the phase difference between the first moment and the second moment; the phase difference can be used to describe the change of the surface displacement of the measured object.

The output module is used for outputting the extracted phase difference.

Further as a preferred embodiment, the computing module includes:

The extraction unit is used for extracting a pre-phase-shift image group and a post-phase-shift image group from the collected electronic speckle images of the measured object, the pre-phase-shift image group including a plurality of images extracted before the target phase-shift image Phase-shifted images, the post-phase-shifted image group includes multiple phase-shifted images extracted after the target phase-shifted images; the target phase-shifted images are respectively a first phase-shifted image and a second phase-shifted image. For example, use a camera to collect one electron speckle image at one hundred times such as t1, t2...t100, specify time t7 as the first time, time t8 as the second time, and extract the electron speckle images collected at time t7. The speckle image is the first phase shift image, and the electronic speckle image collected at time t8 is extracted as the second phase shift image. For a pre-phase-shift image group, extract the electronic speckle images collected at t8, t9, t10, t11, t12, and t13 respectively to form the first phase-shift image post-phase-shift image group; The electronic speckle images collected at t3, t4, t5, t6, and t7 form the second phase-shift image pre-phase-shift image group, and the electronic speckle images collected at t9, t10, t11, t12, t13, and t14 are extracted respectively. The second phase-shifted image post-phase-shifted image group is formed.

The calculation unit is configured to perform interpolation calculation according to a pre-designed interpolation calculation formula program by using the pre-phase-shift image group and the post-phase-shift image group obtained by extraction. For example, the pre-phase-shift image group composed of the extracted time t1, t2, t3, t4, t5, and t6, and the post-phase-shift image group composed of the time t8, t9, t10, t11, t12, and t13, are used according to the pre-designed The formula program of the interpolation calculation is performed by interpolation calculation, and the other three phase-shift images corresponding to the first phase-shift image at the first moment are obtained. The image group, and the post-phase-shift image group formed at t9, t10, t11, t12, t13, and t14, are interpolated according to the pre-designed interpolation calculation formula program to obtain the second phase-shift image corresponding to the second time. Three phase-shifted images.

Further as a preferred embodiment, the processing module includes:

An analysis unit, configured to analyze the first phase-shift image, the sub-image of the first phase-shift image, the second phase-shift image, and the sub-image of the second phase-shift image, that is, the first phase-shift image required for analyzing the first moment includes the first phase-shift image Four phase-shifted images including the image, and four phase-shifted images including the second phase-shifted image required at the second moment;

a calculation unit, configured to calculate the phase difference between the first moment and the second moment according to a pre-designed calculation formula program of the phase difference in the existing electronic speckle interferometry method;

The extraction unit is used to extract the calculated phase difference.

To sum up, the single-step phase-shift electron speckle interferometry system described in this embodiment has the following advantages:

By using the interpolation calculation method, multiple phase-shift images required before the deformation of the measured object and multiple phase-shift images required after the object is deformed are obtained, instead of the objects collected one by one in the existing phase-shift electronic speckle interferometry method Multiple phase-shift images before and after the object is deformed, eliminating the need for multiple phase-shift images before and after the object is deformed, thus solving the problem that the existing phase-shift electron speckle interferometry method can only be used in static or quasi-static measurement In addition, the measurement method described in this embodiment is to add the concept of interpolation calculation on the basis of the existing phase-shift electronic speckle interferometry, so there is no need to increase the use of additional optical equipment or The arrangement can realize dynamic measurement only by using the existing phase-shift electronic speckle interferometry device, and finally calculate the phase difference, so that the change of the surface displacement of the measured object can be described.

This embodiment also includes a single-step phase-shift electronic speckle interferometry device, including a laser, a camera and a computer, wherein the laser is used to irradiate the measured object to generate an electronic speckle image; the camera is used to collect electronic speckle images. A speckle image; the computer is configured to execute the single-step phase-shift electronic speckle interferometry method to process the collected electronic speckle image.

This embodiment further includes a storage medium, in which processor-executable instructions are stored, and when executed by the processor, the processor-executable instructions are used to perform the single-step phase-shift electronic speckle interferometry described in this embodiment. Measurement methods.

When the single-step phase-shift electronic speckle interferometry system in this embodiment is executed by using a terminal such as a computer to run a corresponding program, the medium refers to a storage module in the terminal such as a computer. When the functions of these methods and media are implemented, the same technical effect as the single-step phase-shift electronic speckle interferometry system of this embodiment can be achieved.

Fig. 3 is the distribution of four phase shift images at each moment obtained by interpolation calculation in the embodiment of the present invention; wherein, the * symbol represents the phase shift image extracted from the collected electron speckle image The image intensity of , the solid point represents the image intensity of the phase-shifted image calculated by interpolation; this figure is based on the single-step phase-shift electron speckle interferometry method, according to the principle of optical measurement, when the phase shift amount is 0 For example, the distribution of the four phase shift maps obtained at each moment is measured; the specific process is as follows:

Taking the phase shift amount of 0 as an example, the phase shift images extracted from the collected electron speckle images are k=1, 5, 9, 13, the intensity of these images should follow a smooth curve, then the corresponding sub- Images k=2, 3, 4, k=6, 7, 8, k=10, 11, 12, k=14, 15, and 16 can be obtained by interpolation; that is, only a certain moment needs to be collected and extracted One phase-shift image of , and the remaining three phase-shift images can be obtained by interpolation. The interpolation result can be expressed as:

I _{mod(k-1,4)+1, k} =I _k

Wherein, when m=mod(k-1,4)+1=1, the phase shift image extracted from the collected electron speckle image corresponds to a 0° phase step, where mod(,) is the modulo or the remainder function; similarly, when m=mod(k-1,4)+1=2, 3, 4, it corresponds to a phase-shifted image with phase steps of 90°, 180°, and 270°. That is to say, m=mod(k-1, 4)+1 is the first subscript of I, when m=mod(k-1, 4)+1 is equal to 1, it means 0° phase step, m When =mod(k-1,4)+1 is equal to 2, it represents a 90° phase step, and when m=mod(k-1,4)+1 is equal to 3, it represents a 180° phase step, m=mod(k When -1,4)+1 equals 4, it represents a 270° phase step. The second subscript k of I refers to the frame number; it should be noted that this interpolation calculation process requires the acquisition of six "extra" phase-shift images before and after the target phase-shift image to be measured, i.e. the pre-phase A group of shifted images and a group of post-phase shifted images, wherein the target phase shifted image is extracted from the acquired electron speckle images, and the pre-phase shifted image group and the post-phase shifted image group are also obtained from the acquired electron speckle images. extracted from the spot image.

Using the above formula, the image intensities of the phase-shifted images shown by the solid circles in Fig. 3 obtained by interpolation can be obtained, that is, the remaining three phase-shifted images obtained by interpolation. In this way, four phase-shifted images required at any moment can be obtained during each image measurement, one of which is directly measured, and the other three are calculated by interpolation. Referring to the curve with a phase step of 0° in FIG. 3 , when the phase shift images extracted from the collected electronic speckle images are k=1, 5, 9, and 13, the corresponding sub-images are k=2 , 3, 4, k=6, 7, 8, k=10, 11, 12, k=14, 15, 16 can be obtained by interpolation, where k=1, 5, 9, 13 The image intensities of the phase-shifted images extracted from the acquired electron speckle images are indicated by the * symbol, k=2, 3, 4, k=6, 7, 8, k=10, 11, 12, k= 14, 15, 16 The image intensities of the phase-shifted images obtained by interpolation are represented by solid dots; similarly, referring to the curve with the phase step size of 90° in Fig. 3, when the electron speckle images obtained from the acquisition are When the extracted phase shift images are k=2, 6, 10, 14, the corresponding sub-images are k=3, 4, 5, k=7, 8, 9, k=11, 12, 13, k=15, 16 and 17 can be obtained by means of interpolation calculation, wherein, the image intensity of the phase-shifted image extracted from the collected electron speckle image when k=2, 6, 10, 14 is represented by the symbol *, k = 3, 4, 5, k = 7, 8, 9, k = 11, 12, 13, k = 15, 16, 17 The image intensities of the phase-shifted images calculated by interpolation are indicated by solid dots; similarly, Referring to the curve with the phase step size of 180° in FIG. 3 , when the phase shift images extracted from the collected electron speckle images are k=3, 7, 11, and 15, the corresponding sub-images are k=4 , 5, 6, k=8, 9, 10, k=12, 13, 14, k=16, 17, 18 can be obtained by interpolation, where k=3, 7, 11, 15 The image intensities of the phase-shifted images extracted from the acquired electron speckle images are denoted by the * symbol, k=4, 5, 6, k=8, 9, 10, k=12, 13, 14, k= 16, 17, 18 The image intensities of the phase-shifted images calculated by interpolation are represented by solid dots; similarly, referring to the curve with the phase step size of 270° in Fig. 3, when the electron speckle images obtained from the acquisition are When the extracted phase shift images are k=4, 8, 12, 16, the corresponding sub-images k=5, 6, 7, k=9, 10, 11, k=13, 14, 15, k=17, 18 and 19 can be obtained by means of interpolation calculation, wherein, the image intensity of the phase-shifted image extracted from the collected electron speckle image when k=4, 8, 12, 16 is represented by the symbol *, k =5, 6, 7, k=9, 10, 11, k=13, 14, 15, k=17, 18, 19 The image intensities of the phase-shifted images calculated by interpolation are indicated by solid dots. According to this method, the distribution of the four phase shift maps at each moment can be obtained.

The above are only preferred embodiments of the present invention, and the present invention is not limited to the above-mentioned embodiments, as long as it achieves the technical effect of the present invention by the same means, all within the spirit and principle of the present invention, do Any modification, equivalent replacement, improvement, etc., should be included within the protection scope of the present invention. Various modifications and changes can be made to its technical solutions and/or implementations within the protection scope of the present invention.

Claims (9)

1. A single-step phase-shifted electronic speckle interferometry method, comprising:

collecting an electronic speckle image of a measured object;

extracting a first phase shift image from the electronic speckle image acquired at a first moment;

extracting a second phase-shift image from the electronic speckle image acquired at the second moment;

performing interpolation calculation on the first phase shift image and the second phase shift image;

generating at least one sub-image of the first phase shift image according to the result of the interpolation calculation;

generating at least one sub-image of the second phase-shift image according to the result of the interpolation calculation;

analyzing the first phase shift image, the sub-image of the first phase shift image, the second phase shift image and the sub-image of the second phase shift image, and calculating and extracting to obtain a phase difference between the first moment and the second moment; the phase difference is used to describe the change in surface displacement of the object being measured.

2. The single-step phase-shifted electronic speckle interferometry method according to claim 1, wherein the step of performing interpolation calculation on the first phase-shifted image and the second phase-shifted image comprises:

extracting a front phase-shift image group and a rear phase-shift image group from the electronic speckle images; the front phase shift image group comprises a plurality of phase shift images extracted before the target phase shift image, and the rear phase shift image group comprises a plurality of phase shift images extracted after the target phase shift image; the target phase shift images are respectively a first phase shift image and a second phase shift image;

and performing interpolation calculation by using the extracted front phase shift image group and the extracted rear phase shift image group.

3. The single-step phase-shifted electronic speckle interferometry method according to claim 2, wherein said interpolation calculation is performed by the following formula:

in the formula I_n2、I_n3、I_n4Sub-images, I, respectively, of the phase-shifted image of the object_n-6、I_n-5、I_n-3、I_n-2、I_n-1Forming the front phase shift image group; i is_n+1、I_n+2、I_n+3、I_n+5、I_n+6And forming the post phase shift image group.

4. A single-step phase-shift electronic speckle interferometry method is characterized by comprising the following steps:

collecting electronic speckle images of a measured object at multiple moments;

performing the measurement method of any one of claims 1 to 3 for the electronic speckle image at any first and second time instants to output a phase difference between the first and second time instants; the phase difference is used to describe the change in surface displacement of the object being measured.

5. A single-step phase-shifted electronic speckle interferometry system, comprising:

the acquisition module is used for acquiring an electronic speckle image of a measured object;

the extraction module is used for extracting a first phase shift image from the electronic speckle images acquired at a first moment and extracting a second phase shift image from the electronic speckle images acquired at a second moment;

the calculation module is used for carrying out interpolation calculation on the first phase shift image and the second phase shift image;

the generating module is used for generating at least one sub-image of the first phase shift image according to the result of the interpolation calculation; and generating at least one sub-image of the second phase-shifted image;

the processing module is used for analyzing the first phase shift image, the sub-image of the first phase shift image, the second phase shift image and the sub-image of the second phase shift image, calculating and extracting the phase difference between the first moment and the second moment; the phase difference is used for describing the change of the surface displacement of the measured object;

and the output module is used for outputting the extracted phase difference.

6. The system of claim 5, wherein the computing module comprises:

the device comprises an extraction unit, a phase shift unit and a phase shift unit, wherein the extraction unit is used for extracting a front phase shift image group and a rear phase shift image group from an acquired electronic speckle image of a measured object, the front phase shift image group comprises a plurality of phase shift images extracted before a target phase shift image, and the rear phase shift image group comprises a plurality of phase shift images extracted after the target phase shift image; the target phase shift images are respectively a first phase shift image and a second phase shift image;

and the computing unit is used for carrying out interpolation computation by utilizing the extracted front phase shift image group and the extracted rear phase shift image group.

7. The system of claim 5, wherein the processing module comprises:

an analysis unit for analyzing the first phase-shifted image, the sub-image of the first phase-shifted image, the second phase-shifted image at the second time, and the sub-image of the second phase-shifted image;

a calculation unit for calculating a phase difference between the first time and the second time;

and the extraction unit is used for extracting the calculated phase difference.

8. A single-step phase-shift electronic speckle interferometry device is characterized by comprising a laser, a camera and a computer, wherein the laser is used for irradiating a measured object so as to generate an electronic speckle image; the camera is used for collecting electronic speckle images; the computer is configured to perform the method of any one of claims 1-3 to process the acquired electronic speckle images.

9. A storage medium having stored therein processor-executable instructions, which when executed by a processor, are configured to perform the method of claims 1-3.