Dic experimental data collection method and device, equipment and medium

Abstract

The application relates to a DIC experiment data acquisition method, device, equipment and medium, which comprises the following steps: placing a processed DIC test piece on a clamp of a universal testing machine; installing a flash generator on a camera hot shoe, and connecting the positive and negative poles of the flash generator to a voltage collector; installing a single-lens reflex camera on a tripod, so that the single-lens reflex camera faces an image area of the DIC test piece that needs to be acquired; when the image area that needs to be acquired meets preset image size and preset image frame rate, locking the focus section and focal length of the single-lens reflex camera; controlling a preset single-lens reflex camera control program in a terminal device to acquire image data of the image area of the DIC test piece that needs to be acquired, so as to determine image data of DIC experiment data; controlling a voltage acquisition program in the terminal device to acquire working voltage data of the flash generator, so as to determine the acquisition time of the image data; and determining the DIC experiment data according to the image data and the acquisition time of the image data. The application can build a low-cost DIC hardware platform.

Description

Technical Field

[0001] This application relates to the field of digital image experimentation, and in particular to a method for acquiring DIC experimental data, a corresponding device, an electronic device, and a computer-readable storage medium. Background Technology

[0002] Digital Image Correlation (DIC) is a non-contact, full-field measurement method based on image processing and computer vision technologies, used to study the deformation, displacement, and strain of objects. DIC utilizes computer vision technology to calculate the deformation, displacement, and strain of an object by analyzing the pixel displacements of the object across consecutive image frames. It tracks feature points on the object's surface based on the brightness and grayscale information of the image, and then obtains the object's deformation information by matching and tracking the positional changes of these feature points across different image frames. By collecting and analyzing displacement data between different image frames, DIC can calculate key parameters such as the object's strain field, displacement field, and deformation field. This data can be used to evaluate the object's mechanical properties, material characteristics, and structural deformation. DIC has wide applications in engineering, materials science, biomedicine, geology, and other fields. It can be used for constitutive model verification of materials, dynamic response analysis of structures, and fatigue life assessment of components.

[0003] In the current technology, most researchers collect DIC data by purchasing commercially available equipment. However, these devices are often expensive and have certain requirements for the specific hardware brand. Furthermore, the industrial cameras used in traditional DIC have low resolution, and changing lenses and focusing are complicated and inaccurate. In addition, some universal testing machines do not support the synchronization of universal testing machine data and DIC system data, which greatly limits the application of DIC technology in scientific research.

[0004] To address the problems of low resolution industrial cameras used in existing DIC technology, frequent lens changes, and complex and inaccurate focusing operations, as well as the fact that some universal testing machines do not support the synchronization of universal testing machine data and DIC system data, which greatly limits the application of DIC technology in scientific research, the applicant has made corresponding explorations to solve these problems. Summary of the Invention

[0005] The purpose of this application is to solve the above-mentioned problems by providing a method for acquiring DIC experimental data, a corresponding device, an electronic device, and a computer-readable storage medium.

[0006] To achieve the various objectives of this application, the following technical solution is adopted:

[0007] A method for acquiring DIC experimental data, proposed to meet one of the purposes of this application, includes the following steps:

[0008] In response to the DIC specimen installation command, the processed DIC specimen is placed on the fixture of the universal testing machine, and the DIC specimen is kept at a certain distance from the fixture;

[0009] In response to the flash trigger installation command, install the flash trigger on the camera hot shoe and connect the positive and negative terminals of the flash trigger's working indicator light to the voltage acquisition unit;

[0010] In response to the SLR camera installation command, the SLR camera is mounted on a tripod so that it is facing the image area to be acquired from the DIC specimen. When the image area to be acquired meets the preset image size and preset image frame rate, the focal length and focal length of the SLR camera are locked.

[0011] In response to the DIC experimental data acquisition command, when the distance between the DIC specimen and the fixture of the universal testing machine reaches a preset threshold, the preset SLR camera control program in the control terminal device acquires image data of the image area to be acquired on the DIC specimen in order to determine the image data corresponding to the DIC experimental data. The voltage acquisition program in the control terminal device acquires the working voltage data of the flash trigger in order to determine the acquisition time corresponding to the image data.

[0012] The DIC experimental data is determined based on the image data and the corresponding acquisition time to complete the acquisition of DIC experimental data.

[0013] Optionally, before responding to the DIC experimental data acquisition command, the following steps may be included:

[0014] In response to the fill light installation command, mount the fill light on the tripod to adjust the light angle and aim the light at the image area to be acquired on the DIC specimen.

[0015] Optionally, after determining the DIC experimental data based on the image data and the corresponding acquisition time to complete the DIC experimental data acquisition step, the following steps are included:

[0016] The image data acquired by the SLR camera and the operating voltage data acquired by the voltage acquisition device are obtained from the preset database.

[0017] The absolute time corresponding to the first peak of the working voltage data is determined. Based on a preset image data absolute time algorithm, the absolute time corresponding to the peak of the working voltage data collected by the SLR camera and the voltage acquisition device is combined to determine the absolute time image data corresponding to the DIC experimental data.

[0018] Based on the DIC algorithm, the strain data corresponding to the DIC experimental data is calculated from the absolute time image data corresponding to the DIC experimental data.

[0019] Optionally, the step of calculating and determining the strain data corresponding to the DIC experimental data based on the absolute time image data corresponding to the DIC experimental data using the DIC algorithm includes the following steps:

[0020] The speckle images of the DIC specimen before and after deformation are converted to determine the grayscale images of the DIC specimen before and after deformation, and the grayscale distribution function is used to record them.

[0021] The image sub-region of the DIC specimen in the grayscale image before deformation is determined as the reference image sub-region, and the image sub-region of the DIC specimen in the grayscale image after deformation is determined as the target image sub-region.

[0022] When the DIC specimen deforms, a region with the highest gray-scale similarity to the reference image sub-region is searched in the target image sub-region based on a preset similarity correlation function. The displacement of the DIC specimen after deformation is determined based on the correspondence between the reference image sub-region and the target image sub-region.

[0023] The strain data corresponding to the DIC experimental data are determined based on the displacement of the DIC specimen after deformation.

[0024] Optionally, after the step of calculating and determining the strain data corresponding to the DIC experimental data based on the absolute time image data corresponding to the DIC experimental data using the DIC algorithm, the following steps are included:

[0025] Obtain the load corresponding to each frame of image data in the DIC experimental data;

[0026] The stress-strain data corresponding to the DIC experimental data are determined based on the load corresponding to the image data and the strain data corresponding to the DIC experimental data.

[0027] Optionally, the preset absolute time algorithm for image data is T1+(n-1) / a, where T1 is the absolute time corresponding to the first peak value in the working voltage data collected by the voltage acquisition device, n represents the number of frames of the image data, and a is a constant.

[0028] A DIC experimental data acquisition device provided for another purpose of this application includes:

[0029] A DIC experimental data acquisition device, characterized in that it comprises:

[0030] The DIC specimen mounting module is configured to respond to DIC specimen mounting instructions, place the processed DIC specimen on the fixture of the universal testing machine, and keep the DIC specimen at a certain distance from the fixture;

[0031] The flash trigger mounting module is configured to respond to flash trigger mounting instructions, mount the flash trigger on the camera hot shoe, and connect the positive and negative terminals of the flash trigger's working indicator light to the voltage acquisition unit.

[0032] The SLR camera mounting module is configured to respond to the SLR camera mounting command, mount the SLR camera on a tripod, and make the SLR camera face the image area to be acquired on the DIC specimen. When the image area to be acquired meets the preset image size and preset image frame rate, the focal length and focal length of the SLR camera are locked.

[0033] The experimental data acquisition module is configured to respond to DIC experimental data acquisition commands. When the distance between the DIC specimen and the fixture of the universal testing machine reaches a preset threshold, the module controls the preset SLR camera control program in the terminal device to acquire image data of the image area to be acquired on the DIC specimen in order to determine the image data corresponding to the DIC experimental data. The module also controls the voltage acquisition program in the terminal device to acquire the working voltage data of the flash trigger in order to determine the acquisition time corresponding to the image data.

[0034] The experimental data determination module is configured to determine the DIC experimental data based on the image data and the corresponding acquisition time of the image data, so as to complete the acquisition of DIC experimental data.

[0035] An electronic device provided for another purpose of this application includes a central processing unit and a memory, the central processing unit being configured to invoke and run a computer program stored in the memory to perform the steps of the DIC experimental data acquisition method of this application.

[0036] A computer-readable storage medium is provided for another purpose of this application, which stores, in the form of computer-readable instructions, a computer program implemented according to the DIC experimental data acquisition method, which, when called by a computer, executes the steps included in the corresponding method.

[0037] Compared to existing technologies, this application addresses the problems of low resolution industrial cameras used in existing DIC systems, the need for frequent lens changes, and complex and inaccurate focusing operations. Furthermore, some universal testing machines do not support the synchronization of universal testing machine data and DIC system data, significantly limiting the application of DIC technology in scientific research. This application offers the following benefits, including but not limited to:

[0038] Firstly, the DIC experimental data acquisition method of this application can build a low-cost DIC hardware platform in the laboratory when DIC equipment has not been purchased;

[0039] Secondly, the DIC experimental data acquisition method of this application can realize the synchronization of universal testing machine and DIC image data when the existing universal testing machine in the laboratory does not support data synchronization or the data synchronization interface is not open;

[0040] Third, compared with industrial cameras, the DIC experimental data acquisition method of this application has higher resolution and smaller speckle size that can be resolved by SLR cameras, which is beneficial to improving the experimental accuracy. When using a zoom lens, the SLR camera can smoothly change the focal length, which improves the cumbersome operation of changing the focal length of traditional industrial cameras for DIC, which can only change different lenses and the fixed focal length of different lenses. This makes the camera placement more flexible and simplifies the difficulty of the preparation work before the experiment.

[0041] Fourth, the autofocus system and focus peaking system of SLR cameras are superior to those of traditional DIC industrial cameras in terms of focusing speed and accuracy, simplifying the focusing operation and reducing the possibility of focusing failure. Attached Figure Description

[0042] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0043] Figure 1 This is a hardware architecture diagram of the DIC experimental data acquisition method used in this application;

[0044] Figure 2 This is a flowchart illustrating the DIC experimental data acquisition method in the embodiments of this application;

[0045] Figure 3 This is a schematic diagram illustrating the synchronization of universal testing machine data and DIC image data in an embodiment of this application;

[0046] Figure 4 This is a schematic block diagram of the DIC experimental data acquisition device in the embodiments of this application;

[0047] Figure 5 This is a schematic diagram of the structure of the computer device in the embodiments of this application.

[0048] Figure labels: 1. Fill light, 2. Tripod, 3. Flash trigger indicator light, 4. Flash trigger, 5. Camera hot shoe, 6. SLR camera, 7. Voltage acquisition unit, 8. Computer, 9. Universal testing machine, 10. DIC test specimen. Detailed Implementation

[0049] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0050] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this application means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or wireless coupling. The term “and / or” as used herein includes all or any units and all combinations of one or more associated listed items.

[0051] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0052] Those skilled in the art will understand that the terms "client," "terminal," and "terminal device" as used herein include both devices that receive wireless signals, devices that only possess wireless signal receiver capabilities without transmission capabilities, and devices with receiving and transmitting hardware, devices that have receiving and transmitting hardware capable of bidirectional communication over a bidirectional communication link. Such devices may include: cellular or other communication devices such as personal computers or tablets, having single-line displays, multi-line displays, or cellular or other communication devices without multi-line displays; PCS (Personal Communications Service) that can combine voice, data processing, fax, and / or data communication capabilities; PDA (Personal Digital Assistant) that may include a radio frequency receiver, pager, internet / intranet access, web browser, notepad, calendar, and / or GPS (Global Positioning System) receiver; and conventional laptops and / or handheld computers or other devices that have and / or include radio frequency receivers. As used herein, "client," "terminal," and "terminal device" can be portable, transportable, installed in a means of transportation (air, sea, and / or land), or suitable and / or configured to operate locally and / or in a distributed manner, operating in any other location on Earth and / or in space. "Client," "terminal," and "terminal device" as used herein can also be a communication terminal, an internet access terminal, or a music / video playback terminal, such as a PDA, a MID (Mobile Internet Device), and / or a mobile phone with music / video playback capabilities, or a smart TV, set-top box, etc.

[0053] The hardware referred to by the names "server," "client," and "service node" in this application is essentially an electronic device with the equivalent capabilities of a personal computer. It is a hardware device with the necessary components revealed by the von Neumann architecture, such as a central processing unit (including an arithmetic logic unit and a control unit), memory, input devices, and output devices. The computer program is stored in its memory, and the central processing unit loads the program stored in the secondary storage into the main memory to run it, execute the instructions in the program, and interact with the input and output devices to complete specific functions.

[0054] It should be noted that the concept of "server" used in this application can also be extended to the case of server clusters. Based on the network deployment principles understood by those skilled in the art, the servers should be logically divided. Physically, these servers can be independent of each other but accessible through interfaces, or they can be integrated into a single physical computer or a computer cluster. Those skilled in the art should understand this flexibility and should not use it to constrain the implementation of the network deployment method in this application.

[0055] One or more of the technical features of this application, unless explicitly specified herein, can be deployed on a server and accessed by a client remotely calling the online service interface provided by the server, or can be directly deployed and run on a client for access.

[0056] Unless otherwise specified, the neural network models referenced or potentially referenced in this application may be deployed on a remote server and invoked remotely on the client, or deployed on a client with the capability to invoke directly. In some embodiments, when running on the client, the corresponding intelligence may be acquired through transfer learning in order to reduce the requirements on the client's hardware resources and avoid excessive consumption of the client's hardware resources.

[0057] Unless otherwise specified, all data involved in this application may be stored remotely on a server or on a local terminal device, as long as it is suitable for use by the technical solution of this application.

[0058] Those skilled in the art will understand that although the various methods in this application are described based on the same concept and thus present commonality among them, they can be performed independently unless otherwise specified. Similarly, the various embodiments disclosed in this application are all based on the same inventive concept; therefore, concepts expressed in the same way, as well as concepts that are appropriately changed for convenience but are expressed differently, should be understood equivalently.

[0059] Unless otherwise expressly stated, the various embodiments disclosed in this application can be combined in a cross-cutting manner to flexibly construct new embodiments, as long as such combination does not depart from the inventive spirit of this application and can meet the needs of the prior art or solve a certain deficiency in the prior art. Those skilled in the art should be aware of such modifications.

[0060] Please see Figure 1 as well as Figure 2 In one embodiment of the DIC experimental data acquisition method of this application, the following steps are included:

[0061] Step S10: In response to the DIC specimen installation command, place the processed DIC specimen on the fixture of the universal testing machine and keep the DIC specimen at a certain distance from the fixture;

[0062] Specifically, the terminal device can respond to the DIC specimen installation command, drive the processed DIC specimen 10 to be placed on the fixture of the universal testing machine 9, and connect the universal testing machine 9 to the computer 8 to control its operation. At the same time, the universal testing machine control software is opened and the preparation settings are completed. At this time, there is still a certain distance between the fixture of the universal testing machine and the specimen 10.

[0063] Step S20: In response to the flash trigger installation command, install the flash trigger on the camera hot shoe and connect the positive and negative terminals of the flash trigger's working indicator light to the voltage acquisition unit;

[0064] Specifically, the terminal device can respond to the flash trigger installation command, drive the flash trigger 4 to be installed on the camera hot shoe 5, connect the positive and negative poles of the flash trigger working indicator 3 to the voltage acquisition unit 7, connect the voltage acquisition unit 7 to the computer 8, and open the voltage acquisition unit software to complete the preparation settings.

[0065] Step S30: Responding to the SLR camera installation command, install the SLR camera on a tripod so that the SLR camera is facing the image area to be acquired on the DIC specimen. When the image area to be acquired meets the preset image size and preset image frame rate, lock the focal length and focal length of the SLR camera.

[0066] Specifically, the terminal device can respond to the SLR camera installation command, drive the SLR camera to be installed on the tripod 2, adjust the position of the camera 6 so that the camera 6 is facing the area of ​​the specimen 10 where the image needs to be captured, then adjust the focal length and focal length of the camera 6, run the camera control program, and when the area of ​​the image to be captured meets the preset image size and preset image frame rate, lock the focal length and focal length of the SLR camera so that the camera 6 can capture a clear and appropriately sized image.

[0067] Step S40: Responding to the DIC experimental data acquisition command, when the distance between the DIC specimen and the fixture of the universal testing machine reaches a preset threshold, the preset SLR camera control program in the control terminal device acquires image data of the image area to be acquired on the DIC specimen to determine the image data corresponding to the DIC experimental data, and the voltage acquisition program in the control terminal device acquires the working voltage data of the flash trigger to determine the acquisition time corresponding to the image data.

[0068] The terminal device can respond to DIC experimental data acquisition commands, detect whether the distance between the DIC specimen and the fixture of the universal testing machine reaches a preset threshold. When the distance between the DIC specimen and the fixture of the universal testing machine reaches the preset threshold, the terminal device controls the preset SLR camera control program to acquire image data of the image area to be acquired on the DIC specimen, so as to determine the image data corresponding to the DIC experimental data. The terminal device also controls the voltage acquisition program to acquire the working voltage data of the flash trigger, so as to determine the acquisition time corresponding to the image data.

[0069] In some embodiments, the voltage acquisition program in the control terminal device acquires the working voltage data of the flash trigger to determine the acquisition time corresponding to the image data; then, the universal testing machine control program in the terminal device is run and the test is started. Then, when the specimen 10 is about to be subjected to force, the DSLR camera control program in the control terminal device controls the DSLR camera to start taking pictures and acquire image data of the image area to be acquired for the DIC specimen.

[0070] Step S50: Determine the DIC experimental data based on the image data and the corresponding acquisition time of the image data to complete the acquisition of DIC experimental data.

[0071] The DIC experimental data is determined by identifying the image data corresponding to the DIC experimental data and the acquisition time corresponding to the image data. The DIC experimental data is then determined based on the image data and the acquisition time corresponding to the image data to complete the acquisition of the DIC experimental data.

[0072] As can be seen from the above embodiments, compared with the prior art, this application addresses the problems of low resolution industrial cameras used in DIC, frequent lens changes, and complex and inaccurate focusing operations in the prior art. Furthermore, some universal testing machines do not support the synchronization of universal testing machine data and DIC system data, which greatly limits the application of DIC technology in scientific research. This application provides, but is not limited to, the following beneficial effects:

[0073] Firstly, the DIC experimental data acquisition method of this application can build a low-cost DIC hardware platform in the laboratory when DIC equipment has not been purchased;

[0074] Secondly, the DIC experimental data acquisition method of this application can realize the synchronization of universal testing machine and DIC image data when the existing universal testing machine in the laboratory does not support data synchronization or the data synchronization interface is not open;

[0075] Third, compared with industrial cameras, the DIC experimental data acquisition method of this application has higher resolution and smaller speckle size that can be resolved by SLR cameras, which is beneficial to improving the experimental accuracy. When using a zoom lens, the SLR camera can smoothly change the focal length, which improves the cumbersome operation of changing the focal length of traditional industrial cameras for DIC, which can only change different lenses and the fixed focal length of different lenses. This makes the camera placement more flexible and simplifies the difficulty of the preparation work before the experiment.

[0076] Fourth, the autofocus system and focus peaking system of SLR cameras are superior to those of traditional DIC industrial cameras in terms of focusing speed and accuracy, simplifying the focusing operation and reducing the possibility of focusing failure.

[0077] Based on any embodiment of this application, before the step of responding to the DIC experimental data acquisition command, the following steps are included:

[0078] In response to the fill light installation command, mount the fill light on the tripod to adjust the light angle and aim the light at the image area to be acquired on the DIC specimen.

[0079] Specifically, the terminal device can respond to the fill light installation command, mount the fill light on a tripod, adjust the light angle, and aim the light at the image area to be acquired on the DIC specimen.

[0080] Based on any embodiment of this application, after determining the DIC experimental data according to the image data and the corresponding acquisition time of the image data to complete the step of acquiring the DIC experimental data, the following steps are included:

[0081] The image data acquired by the SLR camera and the operating voltage data acquired by the voltage acquisition device are obtained from the preset database.

[0082] The absolute time corresponding to the first peak of the working voltage data is determined. Based on a preset image data absolute time algorithm, the absolute time corresponding to the peak of the working voltage data collected by the SLR camera and the voltage acquisition device is combined to determine the absolute time image data corresponding to the DIC experimental data.

[0083] Based on the DIC algorithm, the strain data corresponding to the DIC experimental data is calculated from the absolute time image data corresponding to the DIC experimental data.

[0084] Specifically, please refer to Figure 3The image data acquired by the SLR camera and the working voltage data acquired by the voltage acquisition device can be obtained from a preset database. For example, the force-absolute time data of the universal testing machine 9 (the frequency of which is derived is the same as the frequency of image acquisition) and the absolute time T1 corresponding to the first voltage peak acquired by the voltage acquisition device 7 are combined based on the preset image data absolute time algorithm to determine the absolute time image data corresponding to the DIC experimental data.

[0085] Specifically, the raw test data collected by the aforementioned testing equipment is synchronized as follows: The absolute time T1 corresponding to the first peak value of image 1 from the image data collected by the SLR camera and the working voltage data collected by the voltage acquisition device is combined into a single data set. The absolute time of subsequent image data is T1 + image acquisition interval time; for example, image 2 corresponds to T1 + 1 / a, and image n corresponds to T1 + (n-1) / a. This yields the absolute time image data. The absolute time values ​​in the data exported from the universal testing machine are matched with the values ​​of the working voltage data T1 collected by the voltage acquisition device. Since the acquisition frequency is the same, subsequent data are sequentially extrapolated. This yields the synchronized image-load-absolute time data.

[0086] Based on the DIC algorithm, the strain data corresponding to the DIC experimental data is calculated from the absolute time image data corresponding to the DIC experimental data.

[0087] In some embodiments, the preset absolute time algorithm for image data is T1+(n-1) / a, where T1 is the absolute time corresponding to the first peak value in the working voltage data collected by the voltage acquisition device, n represents the number of frames of the image data, and a is a constant.

[0088] Based on any embodiment of this application, the step of calculating and determining the strain data corresponding to the DIC experimental data using the absolute time image data corresponding to the DIC experimental data based on the DIC algorithm includes the following steps:

[0089] The speckle images of the DIC specimen before and after deformation are converted to determine the grayscale images of the DIC specimen before and after deformation, and the grayscale distribution function is used to record them.

[0090] The image sub-region of the DIC specimen in the grayscale image before deformation is determined as the reference image sub-region, and the image sub-region of the DIC specimen in the grayscale image after deformation is determined as the target image sub-region.

[0091] When the DIC specimen deforms, a region with the highest gray-scale similarity to the reference image sub-region is searched in the target image sub-region based on a preset similarity correlation function. The displacement of the DIC specimen after deformation is determined based on the correspondence between the reference image sub-region and the target image sub-region.

[0092] The strain data corresponding to the DIC experimental data are determined based on the displacement of the DIC specimen after deformation.

[0093] Specifically, the speckle images of the specimen before and after deformation are first converted to obtain grayscale images before and after deformation, and recorded using grayscale distribution functions f(x,y) and g(x',y'). A sub-region of the specimen in the grayscale image before deformation is defined as the "Reference Subset," and a sub-region of the specimen in the grayscale image after deformation is defined as the "Target Subset." After deformation, the selected correlation function searches for the region in the "Target Subset" with the best grayscale feature similarity to the "Reference Subset." Finally, the displacement of the specimen after deformation can be obtained through the correspondence between the reference subset and the target subset.

[0094] The similarity correlation function is the basis for judging the similarity between the reference sub-region and the target sub-region. It is the foundation of digital image correlation technology. Therefore, it is necessary to choose a function that is simple to operate, has low computational cost, and is robust to interference. The standardized covariance cross-correlation function is generally used.

[0095]

[0096] Among them, f m and g m , respectively, are the average gray values ​​of the reference sub-region and the target sub-region, and p is the deformation parameter vector describing the changes in the position and shape of the sub-region before and after deformation.

[0097] In DIC, the strain data at each point is actually obtained by numerically differentiating the displacement at each point. After obtaining the strain data corresponding to the DIC experimental data, the stress-strain data is obtained by combining the load corresponding to each frame image.

[0098] Based on any embodiment of this application, after the step of calculating and determining the strain data corresponding to the DIC experimental data using the absolute time image data corresponding to the DIC experimental data based on the DIC algorithm, the following steps are included:

[0099] Obtain the load corresponding to each frame of image data in the DIC experimental data;

[0100] The stress-strain data corresponding to the DIC experimental data are determined based on the load corresponding to the image data and the strain data corresponding to the DIC experimental data.

[0101] Please see Figure 4 A DIC experimental data acquisition device, provided to meet one of the purposes of this application, includes a DIC specimen mounting module 1100, a flash trigger mounting module 1200, a DSLR camera mounting module 1300, an experimental data acquisition module 1400, and an experimental data determination module 1500. The DIC specimen mounting module 1100 is configured to, in response to a DIC specimen mounting command, place the processed DIC specimen on the fixture of a universal testing machine, maintaining a certain distance between the DIC specimen and the fixture. The flash trigger mounting module 1200 is configured to, in response to a flash trigger mounting command, mount the flash trigger on the camera's hot shoe and connect the positive and negative terminals of the flash trigger's indicator light to a voltage acquisition unit. The DSLR camera mounting module 1300 is configured to, in response to a DSLR camera mounting command, mount the DSLR camera on a tripod, positioning the DSLR camera directly facing the image area to be acquired from the DIC specimen. When the image area to be acquired meets a preset image size and preset frame rate, the DSLR camera is locked. The camera's focal length and focal length; the experimental data acquisition module 1400 is configured to respond to DIC experimental data acquisition commands, and when the distance between the DIC specimen and the fixture of the universal testing machine reaches a preset threshold, control the preset SLR camera control program in the terminal device to acquire image data of the image area to be acquired on the DIC specimen, so as to determine the image data corresponding to the DIC experimental data, and control the voltage acquisition program in the terminal device to acquire the working voltage data of the flash trigger, so as to determine the acquisition time corresponding to the image data; the experimental data determination module 1500 is configured to determine the DIC experimental data based on the image data and the acquisition time corresponding to the image data, so as to complete the acquisition of DIC experimental data.

[0102] Based on any embodiment of this application, please refer to Figure 5 Another embodiment of this application also provides an electronic device, which can be implemented by a computer device, such as... Figure 5The diagram shows the internal structure of a computer device. The computer device includes a processor, a computer-readable storage medium, a memory, and a network interface connected via a system bus. The computer-readable storage medium stores an operating system, a database, and computer-readable instructions. The database may store control information sequences. When the computer-readable instructions are executed by the processor, the processor can implement a DIC experimental data acquisition method. The processor of the computer device provides computing and control capabilities to support the operation of the entire computer device. The memory of the computer device may store computer-readable instructions. When the computer-readable instructions are executed by the processor, the processor can execute the DIC experimental data acquisition method of this application. The network interface of the computer device is used for communication with a terminal. Those skilled in the art will understand that… Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0103] In this embodiment, the processor is used to execute... Figure 4 The system contains the specific functions of each module and its sub-modules. The memory stores the program code and various data required to execute these modules or sub-modules. The network interface is used for data transmission between the user terminal and the server. In this embodiment, the memory stores the program code and data required to execute all modules / sub-modules in the DIC experimental data acquisition device of this application. The server can call the server's program code and data to execute the functions of all sub-modules.

[0104] This application also provides a storage medium storing computer-readable instructions, which, when executed by one or more processors, cause the one or more processors to perform the steps of the DIC experimental data acquisition method described in any embodiment of this application.

[0105] This application also provides a computer program product, including a computer program / instructions that, when executed by one or more processors, implement the steps of the DIC experimental data acquisition method described in any embodiment of this application.

[0106] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. This computer program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The aforementioned storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0107] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

[0108] In summary, the DIC experimental data acquisition method of this application can build a low-cost DIC hardware platform in the laboratory when DIC equipment has not been purchased.

Claims

1. A method for acquiring DIC experimental data, characterized in that, The steps include the following: In response to the DIC specimen installation command, the processed DIC specimen is placed on the fixture of the universal testing machine, and the DIC specimen is kept at a certain distance from the fixture; In response to the flash trigger installation command, install the flash trigger on the camera hot shoe and connect the positive and negative terminals of the flash trigger's working indicator light to the voltage acquisition unit; In response to the SLR camera installation command, the SLR camera is mounted on a tripod so that it is facing the image area to be acquired from the DIC specimen. When the image area to be acquired meets the preset image size and preset image frame rate, the focal length and focal length of the SLR camera are locked. In response to the DIC experimental data acquisition command, when the distance between the DIC specimen and the fixture of the universal testing machine reaches a preset threshold, the preset SLR camera control program in the control terminal device acquires image data of the image area to be acquired on the DIC specimen in order to determine the image data corresponding to the DIC experimental data. The voltage acquisition program in the control terminal device acquires the working voltage data of the flash trigger in order to determine the acquisition time corresponding to the image data. The DIC experimental data is determined based on the image data and the corresponding acquisition time to complete the acquisition of DIC experimental data.

2. The DIC experimental data acquisition method according to claim 1, characterized in that, Before responding to the DIC experimental data acquisition command, the following steps are included: In response to the fill light installation command, mount the fill light on the tripod to adjust the light angle and aim the light at the image area to be acquired on the DIC specimen.

3. The DIC experimental data acquisition method according to claim 1, characterized in that, After determining the DIC experimental data based on the image data and the corresponding acquisition time, and completing the step of acquiring the DIC experimental data, the following steps are included: The image data acquired by the SLR camera and the operating voltage data acquired by the voltage acquisition device are obtained from the preset database. The absolute time corresponding to the first peak of the working voltage data is determined. Based on a preset image data absolute time algorithm, the absolute time corresponding to the peak of the working voltage data collected by the SLR camera and the voltage acquisition device is combined to determine the absolute time image data corresponding to the DIC experimental data. Based on the DIC algorithm, the strain data corresponding to the DIC experimental data is calculated from the absolute time image data corresponding to the DIC experimental data.

4. The DIC experimental data acquisition method according to claim 3, characterized in that, The steps for calculating and determining the strain data corresponding to the DIC experimental data based on the absolute time image data corresponding to the DIC experimental data using the DIC algorithm include the following steps: The speckle images of the DIC specimen before and after deformation are converted to determine the grayscale images of the DIC specimen before and after deformation, and the grayscale distribution function is used to record them. The image sub-region of the DIC specimen in the grayscale image before deformation is determined as the reference image sub-region, and the image sub-region of the DIC specimen in the grayscale image after deformation is determined as the target image sub-region. When the DIC specimen deforms, a region with the highest gray-scale similarity to the reference image sub-region is searched in the target image sub-region based on a preset similarity correlation function. The displacement of the DIC specimen after deformation is determined based on the correspondence between the reference image sub-region and the target image sub-region. The strain data corresponding to the DIC experimental data are determined based on the displacement of the DIC specimen after deformation.

5. The DIC experimental data acquisition method according to claim 3, characterized in that, After determining the strain data corresponding to the DIC experimental data by calculating the absolute time image data corresponding to the DIC experimental data based on the DIC algorithm, the following steps are included: Obtain the load corresponding to each frame of image data in the DIC experimental data; The stress-strain data corresponding to the DIC experimental data are determined based on the load corresponding to the image data and the strain data corresponding to the DIC experimental data.

6. The DIC experimental data acquisition method according to claim 3, characterized in that, The preset absolute time algorithm for image data is T1 + (n-1) / a, where T1 is the absolute time corresponding to the first peak value in the working voltage data collected by the voltage acquisition device, n represents the number of frames of the image data, and a is a constant.

7. A DIC experimental data acquisition device, characterized in that, include: The DIC specimen mounting module is configured to respond to DIC specimen mounting instructions, place the processed DIC specimen on the fixture of the universal testing machine, and keep the DIC specimen at a certain distance from the fixture; The flash trigger mounting module is configured to respond to flash trigger mounting instructions, mount the flash trigger on the camera hot shoe, and connect the positive and negative terminals of the flash trigger's working indicator light to the voltage acquisition unit. The SLR camera mounting module is configured to respond to the SLR camera mounting command, mount the SLR camera on a tripod, and make the SLR camera face the image area to be acquired on the DIC specimen. When the image area to be acquired meets the preset image size and preset image frame rate, the focal length and focal length of the SLR camera are locked. The experimental data acquisition module is configured to respond to DIC experimental data acquisition commands. When the distance between the DIC specimen and the fixture of the universal testing machine reaches a preset threshold, the module controls the preset SLR camera control program in the terminal device to acquire image data of the image area to be acquired on the DIC specimen in order to determine the image data corresponding to the DIC experimental data. The module also controls the voltage acquisition program in the terminal device to acquire the working voltage data of the flash trigger in order to determine the acquisition time corresponding to the image data. The experimental data determination module is configured to determine the DIC experimental data based on the image data and the corresponding acquisition time of the image data, so as to complete the acquisition of DIC experimental data.

8. An electronic device comprising a central processing unit and a memory, characterized in that, The central processing unit is used to invoke and run a computer program stored in the memory to perform the steps of the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, It stores, in the form of computer-readable instructions, a computer program implemented according to any one of claims 1 to 6, which, when invoked by a computer, executes the steps included in the corresponding method.

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