Method and device for measuring stretching optical flow of solid propellant

Abstract

The invention discloses a solid propellant stretching optical flow measurement method and device. The method comprises the following steps: acquiring a surface deformation video sequence of a solid propellant sample under the action of a uniaxial stretching load in real time; on the basis of the surface deformation video sequence, a feature point tracking area is established in a scale distance section of the surface of the sample, initial feature points are arranged by adopting a regular grid point method, and the initial feature points serve as reference tracking points of optical flow tracking and displacement transmission; and based on the displacement data of the reference tracking point, constructing full-field continuous displacement distribution by adopting a bilinear interpolation algorithm, and finally obtaining a two-dimensional full-field displacement field of the sample. The device comprises a data acquisition unit, a feature point tracking unit and a two-dimensional full-field displacement field acquisition unit. According to the method, on the basis of a Lucas-Kanade sparse optical flow algorithm, feature points are selected for calculation in combination with propellant material deformation characteristics; a frame superposition algorithm is designed, and the displacement field measurement precision is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid propellant mechanical property testing, and particularly relates to a solid propellant tensile optical flow measurement method and device. BACKGROUND

[0002] In the research and development and performance evaluation process of a solid rocket engine (SRM), accurate measurement of the deformation behavior of a solid rocket propellant (SP) material under mechanical loading conditions is a key link for understanding the response characteristics, optimizing the charge structure design, and ensuring the working reliability of the engine. Among them, the uniaxial tensile test, as one of the most basic mechanical property testing methods, can effectively obtain the stress-strain relationship of the propellant under axial load, providing important data support for material constitutive model construction, structure integrity analysis, and failure mode research. However, due to the particularity of the material properties of the solid rocket propellant itself and the test environment, the deformation measurement of the propellant during the tensile process faces many technical challenges, and the traditional measurement methods have significant limitations in actual application. Moreover, there is still a significant technical gap in the high-precision non-contact full-field displacement measurement technology for this type of material.

[0003] Solid rocket propellants usually have low modulus, relatively soft texture, smooth surface and no ideal bonding characteristics. These material characteristics make it difficult to effectively implement conventional contact deformation measurement methods. For example, strain gauge-based contact measurement methods rely on sensitive elements pasted on the surface of the sample, but due to the low modulus characteristics of the propellant material, the bonding strength between the strain gauge and the sample is often insufficient, and the strain gauge is prone to falling off or peeling off during the test loading, especially in the large deformation stage, resulting in the interruption of the measurement signal and the inability to obtain complete and reliable deformation data. In addition, even if the initial bonding is stable, with the appearance of large deformation, even local necking, crack initiation and other phenomena of the material during the loading process, the relative displacement of the strain gauge and the substrate or the damage of the bonding layer will quickly lead to measurement failure, seriously affecting the continuity and effectiveness of the test data. At the same time, as a typical non-contact optical measurement method, digital image correlation (DIC) technology has been widely used in the field of material deformation measurement in recent years. It realizes full-field strain analysis by preparing random speckle patterns on the surface of the sample and tracking the displacement of the feature area in the image. However, for solid rocket propellants, their surfaces are usually smooth and lack natural texture, and it is difficult for conventional methods to prepare stable and high-contrast speckle markers on their surfaces. Even if the speckle is formed by artificial spraying, it is easy to appear speckle tearing, local feature loss or even complete identification problem during large deformation, which further leads to the DIC algorithm unable to effectively extract displacement information in the key deformation area (such as high strain area, near crack tip, etc.), and the measurement result has a significant blind area, which cannot meet the demand of accurately obtaining the full sample continuous deformation field.

[0004] Currently, for the mechanical property test of solid rocket propellant, especially the deformation measurement under uniaxial tensile condition, the existing technology mainly relies on contact sensors and limited non-contact optical means, but both have obvious applicability defects and technical bottlenecks: on the one hand, the contact method is limited by the material adhesion characteristics and large deformation adaptability, and cannot realize full-range continuous and reliable measurement; on the other hand, although the DIC technology based on speckle marking can realize non-contact measurement, it has strong dependence on surface features, and it is difficult to ensure the stability and integrity of the speckle on the surface of special materials such as propellant, resulting in the risk of measurement failure in actual application. More importantly, in the field of uniaxial tensile test of solid rocket propellant, there is no technical solution that can realize high-precision, full-field displacement measurement without surface marking, using a single camera optical system combined with advanced image processing algorithms (such as optical flow method) - that is, without preparing additional speckle markers on the sample surface, it can obtain continuous and complete two-dimensional full-field displacement field by tracking the pixel-level motion information in the image sequence in real time, thereby effectively overcoming the shortcomings of traditional methods in terms of material adaptability, measurement continuity and feature missing area analysis capability. This technical gap not only limits the in-depth understanding of the real deformation behavior of solid rocket propellant under large deformation conditions, but also poses a serious challenge to the reliability and integrity of related test data, and new non-contact full-field displacement measurement methods need to be developed to meet the engineering practical needs and scientific research requirements of solid rocket propellant mechanical property testing. SUMMARY

[0005] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a low-cost, high-precision solid propellant tensile optical flow measurement method and device, which solves the problems of complex equipment and tedious preprocessing in the prior art. The present application is based on Lucas-Kanade sparse optical flow algorithm, combined with the deformation characteristics of propellant material to select feature points for calculation; design frame superposition algorithm to improve the measurement accuracy of displacement field.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: A solid propellant tensile optical flow measurement method, comprising the following steps: 1) Real-time acquisition of surface deformation video sequence of solid propellant sample under uniaxial tensile load, wherein the video frame rate is not less than 60 fps, and the resolution is not less than 1920x1080 pixels; 2) Based on the surface deformation video sequence, a feature point tracking area is established in the gauge length section of the sample surface, and a regular grid point method is used to arrange initial feature points, which are used as reference tracking points for optical flow tracking and displacement transmission; 3) Based on the displacement data of the reference tracking points, a bilinear interpolation algorithm is used to construct a full-field continuous displacement distribution, and a two-dimensional full-field displacement field of the sample is finally obtained.

[0007] Further improvement of the present application is that in step 1), the surface deformation video sequence of the solid propellant sample under the action of uniaxial tensile load is collected in real time by a high-resolution camera system.

[0008] Further improvement of the present application is that in step 2), the layout interval of the initial feature points is set to 20-40 pixels.

[0009] Further improvement of the present application is that in step 2), the tracking of the initial feature points is realized based on an improved Lucas-Kanade optical flow algorithm, and a pyramid hierarchical calculation framework is used to improve the tracking robustness and calculation efficiency.

[0010] Further improvement of the present application is that in step 3), the calculation of the two-dimensional full-field displacement field uses a recursive cross-frame displacement transmission mechanism to establish the displacement accumulation relationship between adjacent frames.

[0011] Further improvement of the present application is that in step 3), the displacement vector of the two-dimensional full-field displacement field is calculated by the following formula:

[0012] Wherein: represents the displacement vector at position in the frame, which contains the horizontal displacement and the vertical displacement component of the material at position is the inter-frame displacement increment calculated by the Lucas-Kanade optical flow method, which reflects the local deformation information of the material from the frame to the frame; The calculation of the inter-frame displacement increment is based on the brightness constancy assumption, that is:

[0013] Wherein: represents the gray value of the frame image at position By first-order Taylor expansion of the above equation and ignoring the second-order and higher-order terms, the basic equation of the optical flow is obtained:

[0014] In the formula, represents the spatial gradient of the image, represents the time gradient. ​​​​​​​​

[0015] Further improvement of the present application is that in the actual calculation process, a local window of 15*15 pixels is used to solve the basic equation of optical flow, and the displacement increment at each feature point is estimated .

[0016] A solid propellant tensile optical flow measurement device comprises: A data acquisition unit acquires a surface deformation video sequence of a solid propellant sample under the action of a uniaxial tensile load in real time, wherein the video frame rate is not less than 60 fps, and the resolution is not less than 1920*1080 pixels; A feature point tracking unit establishes a feature point tracking area in a gauge section of the sample surface based on the surface deformation video sequence, and arranges initial feature points by using a regular grid point method, wherein the initial feature points are used as reference tracking points for optical flow tracking and displacement transmission; A two-dimensional full-field displacement field acquisition unit uses a bilinear interpolation algorithm to construct a full-field continuous displacement distribution based on the displacement data of the reference tracking points, and finally obtains a two-dimensional full-field displacement field of the sample.

[0017] Further improvement of the present application is that in the data acquisition unit, a high-resolution camera system is used to acquire a surface deformation video sequence of a solid propellant sample under the action of a uniaxial tensile load in real time.

[0018] Further improvement of the present application is that in the two-dimensional full-field displacement field acquisition unit, a recursive cross-frame displacement transmission mechanism is used for the calculation of the two-dimensional full-field displacement field, and a displacement accumulation relationship between adjacent frames is established.

[0019] Compared with the prior art, the present application has at least the following beneficial technical effects: The present application provides a solid propellant tensile optical flow measurement method and device, which realizes high-precision and high-efficiency deformation monitoring of a solid propellant under quasi-static loading conditions by using a recursive optical flow cross-frame displacement transmission mechanism, an optimized regular grid point feature selection strategy (with a distance of 20 pixels) and a bilinear interpolation displacement field reconstruction algorithm, the measurement error is only 1.86%, and the device is integrated into a PyQt cross-platform automatic measurement device to realize efficient processing of the whole process from video input to result output, thereby providing a reliable technical means for the structural integrity evaluation of a solid propellant. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0021] Figure 1 Figure 1 is a schematic diagram of a solid rocket propellant uniaxial tensile measurement device based on optical flow method according to the present application.

[0022] Figure 2 Figure 2 is a shape and size diagram (mm) of a test piece used in the present application.

[0023] Figure 3 Figure 3 is an interface diagram of a measurement device according to the present application.

[0024] Figure 4 Figure 4 is a structure block diagram of a measurement device according to the present application.

[0025] Reference signs shown in the drawings: 1, optical flow method camera; 2, uniaxial tensile testing machine; 3, left 45-degree angle illumination light source; 4, right 45-degree angle illumination light source. DETAILED DESCRIPTION

[0026] Hereinafter, only certain exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0027] In the description of the present application, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0028] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features referred to. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0029] In the present application, unless specifically defined otherwise and limited in the specification, the terms "mount", "connected", "connection", "fixed", and the like, should be construed broadly and do not necessarily require a direct connection or attachment between two elements. These terms can include indirect connections between two elements in the form of an indirect connection through one or more intermediate elements. In addition, a connection between two elements can be a mechanical connection, an electrical connection, or a communication connection. It will be apparent to those skilled in the art that these terms can have the same meaning as the corresponding terms used in the art.

[0030] In the present application, unless specifically defined otherwise and limited in the specification, "on" or "under" of a first feature to a second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "over" of a first feature to a second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. "Under", "below" and "underneath" of a first feature to a second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0031] It should be understood that the terms "comprise" and "include" as used in the specification and the appended claims indicate the presence of the described features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0032] It should also be understood that the terms used in the present application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the present application specification and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0033] It should be further understood that the term "and / or" as used in the present application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations thereof.

[0034] Various structural diagrams according to the disclosed embodiments of the present application are shown in the accompanying drawings. These drawings are not drawn to scale, in which certain details are exaggerated for the purpose of clarity and certain details can be omitted. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are only exemplary, and in actuality there can be deviations due to manufacturing tolerances or technical limitations, and regions / layers with different shapes, sizes and relative positions can be additionally designed by those skilled in the art according to actual needs.

[0035] Embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0036] Embodiment 1 The present application provides a solid propellant tensile optical flow measurement method, comprising the following steps: 1) Real-time acquisition of surface deformation video sequence of a solid propellant sample under uniaxial tensile load, wherein the video frame rate is not less than 60 fps, and the resolution is not less than 1920x1080 pixels; 2) Based on the surface deformation video sequence, a feature point tracking area is established in the sample surface gauge section, and a regular grid point method is used to arrange initial feature points, which are used as reference tracking points for optical flow tracking and displacement transmission; 3) Based on the displacement data of the reference tracking points, a bilinear interpolation algorithm is used to construct a continuous displacement distribution of the whole field, and finally a two-dimensional whole field displacement field of the sample is obtained.

[0037] In this embodiment, in step 1), a high-resolution camera system is used to real-time acquire surface deformation video sequence of a solid propellant sample under uniaxial tensile load.

[0038] In this embodiment, in step 2), the arrangement interval of the initial feature points is set to 20-40 pixels.

[0039] In this embodiment, in step 2), the tracking of the initial feature points is based on the improved Lucas-Kanade optical flow algorithm, and a pyramid hierarchical calculation framework is used to improve the tracking robustness and calculation efficiency.

[0040] In this embodiment, in step 3), the calculation of the two-dimensional whole field displacement field uses a recursive cross-frame displacement transmission mechanism to establish the displacement accumulation relationship between adjacent frames.

[0041] In this embodiment, in step 3), the displacement vector of the two-dimensional whole field displacement field is calculated by the following formula:

[0042] Wherein: represents the displacement vector at position in frame, which includes the horizontal displacement component of the material at position and the vertical displacement component of the material at position ; represents the displacement vector at position in frame, which includes the horizontal displacement component of the material at position and the vertical displacement component of the material at position ; represents the displacement vector at position in frame, which includes the horizontal displacement component of the material at position and the vertical displacement component of the material at position ; represents the displacement vector at position in frame, which includes the horizontal displacement component of the material at position and the vertical displacement component of the material at position ; represents the displacement vector at position in frame, which includes the horizontal displacement component of the material at position and the vertical displacement component of the material at position ; represents the displacement vector at position in frame, which includes the horizontal displacement component of the material at position and the vertical displacement component of the material at position ; represents the displacement vector at position in frame, which includes the horizontal displacement component of the material at position and the vertical displacement component of the material at position ; represents the displacement vector at position in frame, which includes the horizontal displacement component of the material at position and the vertical displacement component of the material at position ; represents the displacement vector at position in frame, which includes the horizontal displacement component of the material at position and the vertical displacement component of the material at position ; The calculation of the inter-frame shift increment is based on the assumption of constant brightness, that is:

[0043] in: Indicates the first Frame image in The gray value at the location; by performing a first-order Taylor expansion on the above equation and ignoring second-order and higher-order terms, the fundamental equation of optical flow is obtained:

[0044] In the formula, Represents the spatial gradient of an image. This represents the time gradient.

[0045] In this embodiment, a 15×15 pixel local window is used to solve the fundamental optical flow equations and estimate the displacement increment at each feature point during the actual calculation process. .

[0046] Example 2 like Figure 4 As shown, the present invention provides a solid propellant tensile optical flow measurement device, comprising: The data acquisition unit acquires real-time video sequences of surface deformation of solid propellant samples under uniaxial tensile load, with a video frame rate of no less than 60fps and a resolution of no less than 1920×1080 pixels. The feature point tracking unit establishes a feature point tracking area within the gauge length of the sample surface based on the surface deformation video sequence, and uses a regular grid point method to lay out the initial feature points, which serve as the reference tracking points for optical flow tracking and displacement transfer. The two-dimensional full-field displacement field acquisition unit uses bilinear interpolation algorithm to construct a continuous full-field displacement distribution based on the displacement data of the reference tracking point, and finally obtains the two-dimensional full-field displacement field of the sample.

[0047] In the data acquisition unit of this embodiment, a high-resolution camera system is used to acquire video sequences of surface deformation of solid propellant samples under uniaxial tensile load in real time.

[0048] In the two-dimensional full-field displacement field acquisition unit of this embodiment, the calculation of the two-dimensional full-field displacement field adopts a recursive cross-frame displacement transfer mechanism, which establishes the displacement accumulation relationship between adjacent frames.

[0049] Example 3 The present invention provides a solid propellant tensile optical flow measurement device, comprising: 1) System hardware configuration like Figure 1As shown, the measuring device of the present application includes an optical flow camera 1 and a single-axis tensile testing machine 2. In the figure, 3 represents a left 45-degree angle illumination light source, and 4 represents a right 45-degree angle illumination light source. The measuring device hardware used in the embodiment of the present application includes: a CTM8010 universal material testing machine (range 10kN), an Olympus EM52 micro single-lens reflex camera (resolution 1920x1080 pixels), a Panasonic lens (focal length 25mm, aperture 1.7), and a LED coaxial light source (power 50W). The sample used is a QJ925-85 standard dumbbell-shaped solid propellant test piece, and the gauge length section size is 70mmx10mmx10mm, as shown in Figure 2 .

[0050] 2) Image acquisition settings In implementation, the industrial camera is fixed at 55cm in front of the testing machine, and is kept horizontal with the center of the sample. The camera parameter settings are: frame rate 60fps, aperture f / 1.7. The light source is arranged at a 45° angle, and the illumination intensity is adjusted to 8000lux, and a quasi-static tensile rate of 10mm / min is maintained during loading.

[0051] 3) Feature point setting and tracking In the image processing software, a ROI area of 90pxx360px (corresponding to the gauge length section of the sample) is demarcated, and the feature points are arranged using the regular grid point method. In the embodiment, three grid spacings of 20px, 30px and 40px are tested respectively, and through comparison, it is found that the 30px spacing achieves the best balance in terms of calculation efficiency and measurement accuracy (calculation time saved by 40%, displacement error <2%). The improved Lucas-Kanade optical flow algorithm is used for feature point tracking, and the pyramid level is set to 3, and the window size is 15x15 pixels.

[0052] 4) Displacement field calculation implementation In implementing displacement calculation, first, a reference coordinate system is established for the first frame of image. For the subsequent nth frame, the following steps are performed: Calculate the feature point displacement increment Δd of the current frame and the previous frame; Update the global displacement by the displacement transmission formula d n =d n-1 +Δd.

[0053] 5) Displacement field reconstruction implementation In reconstructing the full-field displacement using the bilinear interpolation algorithm, the implementation process includes: Establishing a regular interpolation grid (corresponding to a 30px spacing); Selecting four vertices of each grid as A, B, C, D as the four interpolation points for bilinear interpolation; Calculating the displacement of any position within each grid according to the following formula and ):

[0054] As Figure 3 shown, the interface region is subjected to displacement continuity constraint, and a transition band width of 3px is set.

[0055] 6) System software implementation The measurement device software is developed using Python 3.8, and the main modules include: Data processing module: optical flow calculation is realized using OpenCV, and matrix operation is realized using numpy; Video loading module: import the video file to be measured; Progress display module: real-time display of calculation progress; Visualization module: displacement cloud map is drawn using Matplotlib, and the color scale range is set to 0-40mm.

[0056] 7) Typical measurement results At a stretching rate of 10mm / min, the system measured: The maximum displacement field is 37.42mm (nominal value 38.11mm); The system repeatability error is <1.2%.

[0057] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. For those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and the present application can be realized in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be considered as limiting the claims involved.

[0058] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be properly combined to form other embodiments that those skilled in the art can understand. The above content only illustrates the technical idea of the present application, and cannot limit the protection scope of the present application, and any modification made on the basis of the technical solutions according to the present application falls within the protection scope of the claims of the present application.

Claims

1. A method of solid propellant stretch optical flow measurement, characterized in that, The method comprises the following steps: 1) collecting a surface deformation video sequence of a solid propellant sample under a uniaxial tensile load in real time, wherein a video frame rate is not less than 60 fps and a resolution is not less than 1920*1080 pixels; 2) establishing a feature point tracking area in a gauge section on the surface of the sample based on the surface deformation video sequence, and arranging initial feature points by using a regular grid point method, wherein the initial feature points are used as reference tracking points for optical flow tracking and displacement transmission; 3) constructing a full-field continuous displacement distribution by using a bilinear interpolation algorithm based on displacement data of the reference tracking points, and finally obtaining a two-dimensional full-field displacement field of the sample.

2. A method of solid propellant stretch optical flow measurement according to claim 1, wherein, In step 1), a high-resolution camera system is used to collect a surface deformation video sequence of a solid propellant sample under a uniaxial tensile load in real time.

3. The method of claim 1, wherein, In step 2), the arrangement interval of the initial feature points is set to 20-40 pixels.

4. The method of claim 1, wherein, In step 2), the tracking of the initial feature points is realized based on an improved Lucas-Kanade optical flow algorithm, and a pyramid hierarchical calculation framework is used to improve the tracking robustness and calculation efficiency.

5. The method of claim 1, wherein, In step 3), the calculation of the two-dimensional full-field displacement field is realized by using a recursive cross-frame displacement transmission mechanism to establish a displacement accumulation relationship between adjacent frames.

6. A method of solid propellant stretch optical flow measurement according to claim 5, wherein, In step 3), the displacement vectors of the two-dimensional full-field displacement field are calculated by using the following formula: wherein: represents the displacement vector at position in the frame , which contains the horizontal displacement and the vertical displacement components of the material at position ; is the inter-frame displacement increment calculated by Lucas-Kanade optical flow method, which reflects the local deformation information of the material from the frame to the frame . The calculation of the inter-frame displacement increment is based on the brightness constancy assumption, that is: wherein: represents the gray value of the frame image at position; by performing a first-order Taylor expansion on the above equation and ignoring the second-order and higher-order terms, the optical flow basic equation is obtained: wherein denotes the spatial gradient of the image, denotes the temporal gradient.

7. A method of solid propellant stretch optical flow measurement according to claim 6, wherein, In the actual calculation process, a local window of 15x15 pixels is used to solve the basic equation of optical flow, and the displacement increment at each feature point is estimated .

8. A solid propellant tensile optical flow measurement device, characterized by, The method comprises the following steps: a data acquisition unit configured to collect a surface deformation video sequence of a solid propellant sample under a uniaxial tensile load in real time, wherein a video frame rate is not less than 60 fps and a resolution is not less than 1920*1080 pixels; a feature point tracking unit configured to establish a feature point tracking area in a gauge section on the surface of the sample based on the surface deformation video sequence, and arrange initial feature points by using a regular grid point method, wherein the initial feature points are used as reference tracking points for optical flow tracking and displacement transmission; a two-dimensional full-field displacement field obtaining unit configured to construct a full-field continuous displacement distribution by using a bilinear interpolation algorithm based on displacement data of the reference tracking points, and finally obtain a two-dimensional full-field displacement field of the sample.

9. A solid propellant stretch optical flow measurement device according to claim 8, wherein, In the data acquisition unit, a high-resolution camera system is used to collect a surface deformation video sequence of a solid propellant sample under a uniaxial tensile load in real time.

10. A solid propellant stretch optical flow measurement device according to claim 8, wherein, In the two-dimensional full-field displacement field obtaining unit, the calculation of the two-dimensional full-field displacement field is realized by using a recursive cross-frame displacement transmission mechanism to establish a displacement accumulation relationship between adjacent frames.

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