A method and device for structural vibration analysis based on video images

Abstract

The present invention relates to a structural vibration analysis method and device based on video images, comprising: acquiring a video image of an object to be tested vibrating along a vibration direction frame by frame, converting each frame of the video image into a grayscale image, intercepting a specified area of each grayscale image frame, and calculating the maximum pixel value in the specified area of each grayscale image frame, and analyzing the vibration frequency and / or vibration amplitude of the object to be tested based on the maximum pixel value in the specified area of each grayscale image frame, wherein the specified area of each grayscale image frame has the same position on each grayscale image frame and includes a boundary in the vibration direction of the object to be tested and a column of pixel points in the neighborhood of the boundary. The technical solution provided by the present invention can accurately analyze and obtain the vibration frequency and / or vibration amplitude of the object to be tested by using the real pixel values corresponding to the grayscale image of the intercepted video image of the object to be tested vibrating along the vibration direction, with low computational complexity and high speed.

Description

Technical Field

[0001] The present invention relates to the field of structural vibration, and in particular to a structural vibration analysis method and device based on video images. Background Art

[0002] In recent years, with the increase in voltage levels, the hardware structure has also become larger, leading to an increasing number of common mechanical failures such as conductor galloping, sub-span oscillation, breeze vibration, wind deflection, and transmission tower vibration. Dynamic problems such as shield ring flutter and insulator string vibration are also becoming increasingly prominent. These mechanical failures can cause line short circuits and tripping at the least, or even cause tower collapse and line breakage at the most serious. This poses a significant threat to the safe and stable operation of the transmission line. For mechanical failures that have already occurred on the line, it is necessary to first assess the fault situation on site or analyze the measurement data of the fault object on site, and then propose optimization solutions or solutions to eliminate the fault. Currently, most measurements of fault objects on site are contact measurements. Contact measurements require the operation and maintenance department to coordinate power outages or workers to install sensors at the measurement location while working under power. The installation of contact sensors also adds additional weight to the measured object, which has a certain impact on line operation and measurement accuracy.

[0003] Current methods of applying video surveillance images to structural vibration measurement generally only focus on the extraction of vibration frequency and mode shape, and are computationally intensive, slow, and result in inaccurate analysis. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a structural vibration analysis method and device based on video images, which analyzes the vibration frequency and / or vibration amplitude of the object to be measured according to the real pixel values corresponding to each frame of grayscale image, thereby improving the accuracy of structural vibration analysis of video images.

[0005] The purpose of the present invention is achieved by adopting the following technical solutions:

[0006] The present invention provides a structural vibration analysis method based on video images, wherein the method comprises:

[0007] Acquire video images of the object under test vibrating along the vibration direction frame by frame, and convert each frame of the video image into a grayscale image;

[0008] intercepting a designated area of each frame of grayscale image, and calculating a maximum pixel value in the designated area of each frame of grayscale image;

[0009] Analyzing the vibration frequency and / or vibration amplitude of the object to be measured according to the maximum pixel value in the designated area of each frame of the grayscale image;

[0010] The designated areas of each frame of grayscale image have the same position on each frame of grayscale image and both include a boundary in the vibration direction of the object to be measured and a column of pixel points in the neighborhood of the boundary.

[0011] Preferably, the number of pixel points in the column is greater than or equal to three.

[0012] Preferably, the calculating of the maximum pixel value in a specified area of each frame of the grayscale image includes:

[0013] Obtaining differential values of pixels in a designated area of the grayscale image of the i-th frame, and taking a pixel value corresponding to a maximum value among the differential values as a maximum pixel value in the designated area of the grayscale image;

[0014] Wherein, i∈[1~n], n is the total number of frames of the video image of the object to be tested.

[0015] Preferably, analyzing the vibration frequency and / or vibration amplitude of the object to be measured according to the maximum pixel value in the designated area of each frame of the grayscale image includes:

[0016] Removing the DC component of the maximum pixel value in the specified area of each frame of grayscale image to obtain the true pixel value corresponding to each frame of grayscale image;

[0017] The vibration frequency and / or vibration amplitude of the object to be measured is analyzed according to the real pixel values corresponding to each frame of grayscale image.

[0018] Furthermore, the step of removing the DC component of the maximum pixel value in the designated area of each frame of grayscale image to obtain the true pixel value corresponding to each frame of grayscale image includes:

[0019] Determine the true pixel value P corresponding to the grayscale image of the i-th frame as follows: r,i :

[0020] P r,i =P i -P m

[0021] In the above formula, P i is the maximum pixel value in the specified area of the grayscale image of the i-th frame, P m It is the average value of the maximum pixel values in the specified area of each frame of grayscale image.

[0022] Furthermore, analyzing the vibration frequency and / or vibration amplitude of the object to be measured according to the real pixel values corresponding to each frame of grayscale image includes:

[0023] The pixel sequence is composed of the real pixel values corresponding to each frame of grayscale image;

[0024] Performing Fourier transform on the pixel sequence to obtain the vibration frequency of the object to be measured;

[0025] And / or based on the pixel sequence, the vibration amplitude Z of the object to be measured is determined according to the following formula:

[0026]

[0027] In the above formula, Y is the length of the object to be measured, M is the amplitude of the pixel sequence, and G is the number of pixels occupied by the projection of the object to be measured on the image.

[0028] Based on the same inventive concept, the present invention provides a structural vibration analysis device based on video images, wherein the improvement is that the device comprises:

[0029] A conversion module, used to obtain a video image of the object under test vibrating along the vibration direction frame by frame, and convert each frame of the video image into a grayscale image;

[0030] a calculation module, configured to intercept a designated area of each frame of grayscale image and calculate a maximum pixel value in the designated area of each frame of grayscale image;

[0031] an analysis module, configured to analyze the vibration frequency and / or vibration amplitude of the object to be measured based on the maximum pixel value in the designated area of each frame of the grayscale image;

[0032] The designated areas of each frame of grayscale image have the same position on each frame of grayscale image and both include a boundary in the vibration direction of the object to be measured and a column of pixel points in the neighborhood of the boundary.

[0033] Preferably, the number of pixel points in the column is greater than or equal to three.

[0034] Preferably, the calculating of the maximum pixel value in a specified area of each frame of the grayscale image includes:

[0035] Obtaining differential values of pixels in a designated area of the grayscale image of the i-th frame, and taking a pixel value corresponding to a maximum value among the differential values as a maximum pixel value in the designated area of the grayscale image;

[0036] Wherein, i∈[1~n], n is the total number of frames of the video image of the object to be tested.

[0037] Preferably, the analysis module includes:

[0038] An acquisition unit, configured to remove the DC component of the maximum pixel value in a specified area of each frame of grayscale image, and acquire the true pixel value corresponding to each frame of grayscale image;

[0039] The analyzing unit is used to analyze the vibration frequency and / or vibration amplitude of the object to be measured according to the real pixel values corresponding to each frame of grayscale image.

[0040] Furthermore, the acquisition unit is specifically configured to:

[0041] Determine the true pixel value P corresponding to the grayscale image of the i-th frame as follows: r,i :

[0042] P r,i =P i -P m

[0043] In the above formula, P i is the maximum pixel value in the specified area of the grayscale image of the i-th frame, P m It is the average value of the maximum pixel values in the specified area of each frame of grayscale image.

[0044] Furthermore, the analysis unit is specifically used to:

[0045] The pixel sequence is composed of the real pixel values corresponding to each frame of grayscale image;

[0046] Performing Fourier transform on the pixel sequence to obtain the vibration frequency of the object to be measured;

[0047] And / or based on the pixel sequence, the vibration amplitude Z of the object to be measured is determined according to the following formula:

[0048]

[0049] In the above formula, Y is the length of the object to be measured, M is the amplitude of the pixel sequence, and G is the number of pixels occupied by the projection of the object to be measured on the image.

[0050] Compared with the closest prior art, the present invention has the following beneficial effects:

[0051] The present invention provides a method and device for analyzing structural vibrations based on video images, which acquires video images of the object to be tested vibrating along the vibration direction frame by frame, converts each frame of the video image into a grayscale image, intercepts a specified area of each grayscale image frame, and calculates the maximum pixel value in the specified area of each grayscale image frame. The vibration frequency and / or vibration amplitude of the object to be tested are analyzed based on the maximum pixel value in the specified area of each grayscale image frame, wherein the specified area of each grayscale image frame has the same position on each grayscale image frame and contains a column of pixel points of the boundary in the vibration direction of the object to be tested and the neighborhood of the boundary. The technical solution provided by the present invention can accurately analyze and obtain the vibration frequency and / or vibration amplitude of the object to be tested by using the real pixel values corresponding to the grayscale image of the intercepted video image of the object to be tested vibrating along the vibration direction, with low computational complexity and high speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a flow chart of a structural vibration analysis method based on video images provided by the present invention;

[0053] Figure 2It is a pixel gray value difference curve in a structural vibration analysis method based on video images provided by the present invention;

[0054] Figure 3 This is a vibration data diagram before removing the DC component in a structural vibration analysis method based on video images provided by the present invention;

[0055] Figure 4 The present invention provides a method for analyzing structural vibration based on video images, which includes a pixel time series and a spectrum before removing the DC component.

[0056] Figure 5 This is a vibration data diagram after removing the DC component in a structural vibration analysis method based on video images provided by the present invention;

[0057] Figure 6 It is a pixel time series and its spectrum diagram after removing the DC component in a structural vibration analysis method based on video images provided by the present invention;

[0058] Figure 7 This is a schematic diagram of the principle of proportional conversion between objects and images in a structural vibration analysis method based on video images provided by the present invention;

[0059] Figure 8 It is the real vibration amplitude and spectrum diagram of the object to be measured in the structural vibration analysis method based on video images provided by the present invention;

[0060] Figure 9 This is a structural diagram of a video image-based structural vibration analysis device provided by the present invention. DETAILED DESCRIPTION

[0061] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0063] The present invention provides a structural vibration analysis method based on video images, such as Figure 1 As shown, the method includes:

[0064] Acquire video images of the object under test vibrating along the vibration direction frame by frame, and convert each frame of the video image into a grayscale image;

[0065] intercepting a designated area of each frame of grayscale image, and calculating a maximum pixel value in the designated area of each frame of grayscale image;

[0066] Analyzing the vibration frequency and / or vibration amplitude of the object to be measured according to the maximum pixel value in the designated area of each frame of the grayscale image;

[0067] The designated areas of each captured grayscale image frame have the same position on each grayscale image frame and all include a boundary in the vibration direction of the object to be measured and a column of pixel points in the neighborhood of the boundary.

[0068] In an embodiment of the present invention, the number of pixel points in the column is greater than or equal to three.

[0069] In an embodiment of the present invention, the calculating of the maximum pixel value in the designated area of each frame of the grayscale image includes:

[0070] Get the difference value of each pixel in the specified area of the grayscale image of the i-th frame, such as Figure 2 As shown, the pixel value of the pixel point corresponding to the maximum value in the differential value is used as the maximum pixel value in the specified area of the grayscale image;

[0071] Among them, the vibration data of the object to be measured is composed of the maximum pixel value before removing the DC component at the same position of each frame image, such as Figure 3 As shown; the pixel time series and spectrum before removing the DC component composed of the maximum pixel value corresponding to the same position of each frame image in the intercepted specified area, as shown Figure 4 As shown; i∈[1~n], n is the total number of frames of the video image of the object to be tested.

[0072] In an embodiment of the present invention, analyzing the vibration frequency and / or vibration amplitude of the object to be measured according to the maximum pixel value in the designated area of each frame of the grayscale image includes:

[0073] Removing the DC component of the maximum pixel value in the specified area of each frame of grayscale image to obtain the true pixel value corresponding to each frame of grayscale image;

[0074] Analyze the vibration frequency and / or vibration amplitude of the object to be measured based on the real pixel values corresponding to each frame of grayscale image.

[0075] Among them, the maximum pixel value corresponding to the same position of each frame image in the intercepted specified area is removed from the DC component to form the vibration data of the object to be measured, such as Figure 5 As shown in the figure, the pixel time series and its spectrum composed of the maximum pixel value corresponding to the same position of each frame image in the specified area after removing the DC component are shown in the figure. Figure 6 shown.

[0076] Specifically, removing the DC component of the maximum pixel value in the designated area of each frame of grayscale image to obtain the real pixel value corresponding to each frame of grayscale image includes:

[0077] Determine the true pixel value P corresponding to the grayscale image of the i-th frame as follows: r,i :

[0078] P r,i =P i -P m

[0079] In the above formula, P i is the maximum pixel value in the specified area of the grayscale image of the i-th frame, P m It is the average value of the maximum pixel values in the specified area of each frame of grayscale image.

[0080] Specifically, analyzing the vibration frequency and / or vibration amplitude of the object to be measured according to the real pixel values corresponding to each frame of grayscale image includes:

[0081] The pixel sequence is composed of the real pixel values corresponding to each frame of grayscale image;

[0082] Performing Fourier transform on the pixel sequence to obtain the vibration frequency of the object to be measured;

[0083] In the embodiment of the present invention, the vibration amplitude of the object to be measured is calculated based on the principle of "physical object and image ratio conversion", such as Figure 7 As shown, with the lens in a fixed position, O and O1 are points on the object. O and its neighborhood (solid circle) move vertically downward to form O1 and its neighborhood (dashed circle). O' and O1' are corresponding points on the object in the image. OO' is perpendicular to the projection plane, and A is the focus of the lens. BC is the object surface on the same plane as OO1, and DE is the projection of BC on the projection plane. From geometric theory, we know that triangle AOO1 is similar to triangle AO'O1', and triangle ABC is similar to triangle AED. Then the relationship between the sides of the triangle is: Then, based on the pixel sequence, the vibration amplitude Z of the object to be measured is determined according to the following formula:

[0084]

[0085] In the above formula, Y is the length of the object to be measured, M is the amplitude of the pixel sequence, and G is the number of pixels occupied by the projection of the object to be measured on the image. The amplitude of the pixel sequence is obtained according to the difference between the maximum value of the peak and the minimum value of the trough in the waveform corresponding to the pixel sequence. The vibration amplitude and spectrum of the object to be measured are as follows: Figure 8 shown.

[0086] Based on the same inventive concept, the present invention provides a structural vibration analysis device based on video images, such as Figure 9 As shown, the device includes:

[0087] A conversion module, used to obtain a video image of the object under test vibrating along the vibration direction frame by frame, and convert each frame of the video image into a grayscale image;

[0088] a calculation module, configured to intercept a designated area of each frame of grayscale image and calculate a maximum pixel value in the designated area of each frame of grayscale image;

[0089] an analysis module, configured to analyze the vibration frequency and / or vibration amplitude of the object to be measured based on the maximum pixel value in the designated area of each frame of the grayscale image;

[0090] The designated areas of each frame of grayscale image have the same position on each frame of grayscale image and both include a boundary in the vibration direction of the object to be measured and a column of pixel points in the neighborhood of the boundary.

[0091] In an embodiment of the present invention, the number of pixel points in the column is greater than or equal to three.

[0092] In an embodiment of the present invention, the calculating of the maximum pixel value in the designated area of each frame of the grayscale image includes:

[0093] Obtaining differential values of pixels in a designated area of the grayscale image of the i-th frame, and taking a pixel value corresponding to a maximum value among the differential values as a maximum pixel value in the designated area of the grayscale image;

[0094] Wherein, i∈[1~n], n is the total number of frames of the video image of the object to be tested.

[0095] In an embodiment of the present invention, the analysis module includes:

[0096] An acquisition unit, configured to remove the DC component of the maximum pixel value in a specified area of each frame of grayscale image, and acquire the true pixel value corresponding to each frame of grayscale image;

[0097] The analyzing unit is used to analyze the vibration frequency and / or vibration amplitude of the object to be measured according to the real pixel values corresponding to each frame of grayscale image.

[0098] Specifically, the acquisition unit is specifically used to:

[0099] Determine the true pixel value P corresponding to the grayscale image of the i-th frame as follows: r,i :

[0100] P r,i =P i -P m

[0101] In the above formula, Pi is the maximum pixel value in the specified area of the grayscale image of the i-th frame, P m It is the average value of the maximum pixel values in the specified area of each frame of grayscale image.

[0102] Specifically, the analysis unit is specifically used to:

[0103] The pixel sequence is composed of the real pixel values corresponding to each frame of grayscale image;

[0104] Performing Fourier transform on the pixel sequence to obtain the vibration frequency of the object to be measured;

[0105] And / or based on the pixel sequence, the vibration amplitude Z of the object to be measured is determined according to the following formula:

[0106]

[0107] In the above formula, Y is the length of the object to be measured, M is the amplitude of the pixel sequence, and G is the number of pixels occupied by the projection of the object to be measured on the image.

[0108] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0109] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0110] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1The function specified in one or more boxes.

[0111] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A structural vibration analysis method based on video images, characterized in that: The method comprises: Acquire video images of the object under test vibrating along the vibration direction frame by frame, and convert each frame of the video image into a grayscale image; intercepting a designated area of each frame of grayscale image, and calculating a maximum pixel value in the designated area of each frame of grayscale image; Analyzing the vibration frequency and / or vibration amplitude of the object to be measured according to the maximum pixel value in the designated area of each frame of the grayscale image; The designated areas of each frame of grayscale image have the same position on each frame of grayscale image and both include a boundary in the vibration direction of the object to be measured and a column of pixel points in the neighborhood of the boundary.

2. The method according to claim 1, wherein The number of pixel points in the column is greater than or equal to three.

3. The method according to claim 1, wherein Calculating the maximum pixel value in the designated area of each frame of grayscale image includes: Obtaining differential values of pixels in a designated area of the grayscale image of the i-th frame, and taking a pixel value corresponding to a maximum value among the differential values as a maximum pixel value in the designated area of the grayscale image; Wherein, i∈[1~n], n is the total number of frames of the video image of the object to be tested.

4. The method according to claim 1, wherein The analyzing the vibration frequency and / or vibration amplitude of the object to be measured according to the maximum pixel value in the designated area of each frame of the grayscale image includes: Removing the DC component of the maximum pixel value in the specified area of each frame of grayscale image to obtain the true pixel value corresponding to each frame of grayscale image; The vibration frequency and / or vibration amplitude of the object to be measured is analyzed according to the real pixel values corresponding to each frame of grayscale image.

5. The method according to claim 4, wherein The step of removing the DC component of the maximum pixel value in the designated area of each frame of grayscale image to obtain the true pixel value corresponding to each frame of grayscale image includes: Determine the true pixel value P corresponding to the grayscale image of the i-th frame as follows: r,i : P r,i =P i -P m In the above formula, P i is the maximum pixel value in the specified area of the grayscale image of the i-th frame, P m It is the average value of the maximum pixel values in the specified area of each frame of grayscale image.

6. The method according to claim 4, wherein The analyzing the vibration frequency and / or vibration amplitude of the object to be measured according to the real pixel values corresponding to each frame of grayscale image includes: A pixel sequence is formed by the real pixel values corresponding to each frame of grayscale image; and Performing Fourier transform on the pixel sequence to obtain the vibration frequency of the object to be measured; and / or Based on the pixel sequence, the vibration amplitude Z of the object to be measured is determined as follows: In the above formula, Y is the length of the object to be measured, M is the amplitude of the pixel sequence, and G is the number of pixels occupied by the projection of the object to be measured on the image.

7. A structural vibration analysis device based on video images, characterized in that: The device comprises: A conversion module, used to obtain a video image of the object under test vibrating along the vibration direction frame by frame, and convert each frame of the video image into a grayscale image; a calculation module, configured to intercept a designated area of each frame of grayscale image and calculate a maximum pixel value in the designated area of each frame of grayscale image; an analysis module, configured to analyze the vibration frequency and / or vibration amplitude of the object to be measured based on the maximum pixel value in the designated area of each frame of the grayscale image; The designated areas of each frame of grayscale image have the same position on each frame of grayscale image and both include a boundary in the vibration direction of the object to be measured and a column of pixel points in the neighborhood of the boundary.

8. The device according to claim 7, wherein The number of pixel points in the column is greater than or equal to three.

9. The device according to claim 7, wherein Calculating the maximum pixel value in the designated area of each frame of grayscale image includes: Obtaining differential values of pixels in a designated area of the grayscale image of the i-th frame, and taking a pixel value corresponding to a maximum value among the differential values as a maximum pixel value in the designated area of the grayscale image; Wherein, i∈[1~n], n is the total number of frames of the video image of the object to be tested.

10. The device according to claim 7, wherein The analysis module includes: An acquisition unit, configured to remove the DC component of the maximum pixel value in a specified area of each frame of grayscale image, and acquire the true pixel value corresponding to each frame of grayscale image; The analyzing unit is used to analyze the vibration frequency and / or vibration amplitude of the object to be measured according to the real pixel values corresponding to each frame of grayscale image.

11. The device according to claim 10, wherein The acquisition unit is specifically configured to: Determine the true pixel value P corresponding to the grayscale image of the i-th frame as follows: r,i : P r,i =P i -P m In the above formula, P i is the maximum pixel value in the specified area of the grayscale image of the i-th frame, P m It is the average value of the maximum pixel values in the specified area of each frame of grayscale image.

12. The device according to claim 10, wherein The analysis unit is specifically used for: A pixel sequence is formed by the real pixel values corresponding to each frame of grayscale image; and Performing Fourier transform on the pixel sequence to obtain the vibration frequency of the object to be measured; and / or Based on the pixel sequence, the vibration amplitude Z of the object to be measured is determined as follows: In the above formula, Y is the length of the object to be measured, M is the amplitude of the pixel sequence, and G is the number of pixels occupied by the projection of the object to be measured on the image.

Images