A fluid-structure coupling vibration full-field measurement device and method based on event camera

Abstract

The present invention discloses a fluid-solid coupling vibration full-field measurement device and method based on an event camera, the device includes a transparent box, a solid to be measured, a flow field to be measured, an event camera, an identification plate, a scattered light source and a sheet light source; the solid to be measured is arranged inside the transparent box; the flow field to be measured is used to carry particles to flow through the solid to be measured; the event camera is located in front of the transparent box, and a first color is set on the side of the solid to be measured facing the event camera; the identification plate is located behind the transparent box and is set with a second color, which is used to identify the flow field to be measured; the scattered light source and the sheet light source are used for lighting; the flow field to be measured flows through the solid to be measured to induce fluid-solid coupling vibration, the event camera collects the event flow image, and performs fluid-solid image segmentation according to the first color and the second color, and finally obtains the solid vibration characteristics and the flow field characteristics respectively based on the segmented images. The present invention realizes the full-field measurement of the flow field and the solid structure vibration at the same time, and can fully synchronize the measurement of the fluid characteristics and the solid vibration characteristics.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a fluid-solid coupling vibration full-field measurement device and method based on an event camera. Background Art

[0002] Fluid-solid interaction vibration refers to the vibration phenomenon caused by the interaction between fluid medium and solid structure, which is widely present in the fields of engineering and science, such as aerodynamic vibration of wind turbine blades, aerodynamic noise vibration of automobile shells, aerodynamic vibration of aerospace components, etc. In order to observe these complex vibration phenomena, full-field measurement is required to obtain vibration information of fluid medium and solid structure.

[0003] Traditional flow field measurement methods usually use instruments such as Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV) for measurement, while the vibration of solid structures is usually measured by sensors such as accelerometers and strain gauges. However, due to the high-frequency characteristics of fluid-solid coupling vibration, traditional methods often have difficulty accurately capturing subtle vibration phenomena in the flow field.

[0004] The event camera is a new type of sensor with extremely high sampling rate and sensitivity, which can capture rapid changes in the scene, including high-frequency vibrations, at very high speeds. Unlike traditional cameras, event cameras do not collect images at fixed time intervals, but generate pixel-level event data instantly when the scene changes, so it can achieve real-time capture and high-precision measurement of rapid vibrations in the flow field. Summary of the invention

[0005] The purpose of the present invention is to provide a full-field measurement device and method for fluid-solid coupling vibration based on an event camera, so as to realize full-field measurement of flow field and solid structure vibration at the same time, and solve the data coupling problem caused by the traditional method of setting multiple ordinary sensors to measure flow field and solid vibration separately.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A fluid-solid coupling vibration full-field measurement device based on an event camera, the device comprising a transparent box, a solid to be measured, a flow field to be measured, an event camera, a marking plate, a scattering light source and a sheet light source;

[0008] The solid to be tested is placed inside the transparent box;

[0009] The flow field to be measured is used to carry particles to flow through the solid to be measured;

[0010] The event camera is located in front of the transparent box, and a first color is set on a side of the solid to be tested facing the event camera;

[0011] The identification plate is located behind the transparent box and is set to a second color, and is used to identify the flow field to be measured;

[0012] The scattered light source is located in front of the transparent box and is used to illuminate the solid to be tested;

[0013] The sheet light source is used to illuminate the moving particles in the flow field to be measured;

[0014] The flow field to be measured flows through the solid to be measured, causing fluid-solid coupling vibration. The event camera collects event flow images and performs fluid-solid image segmentation according to the first color and the second color. Finally, the solid vibration characteristics and flow field characteristics are respectively obtained based on the segmented images.

[0015] Furthermore, the first color is red and the second color is white.

[0016] Furthermore, the sheet light source is a laser light sheet.

[0017] Furthermore, the device also includes a fixed spring; the solid to be tested is arranged inside the transparent box through the fixed spring.

[0018] A method for measuring fluid-structure coupling vibration in full field based on an event camera, applied to any one of the above-mentioned fluid-structure coupling vibration in full field measurement devices based on an event camera, the method comprising:

[0019] Turn on the scattered light source and the sheet light source, and make the flow field to be measured flow through the solid to be measured;

[0020] The event camera collects event stream images and performs stream-solid image segmentation according to the first color and the second color;

[0021] Based on the segmented images, the solid vibration characteristics and flow field characteristics are respectively obtained, the solid vibration information is recorded using the solid vibration observation method, and the flow field characteristic information is recorded using the flow field observation method.

[0022] Further, the method for observing solid vibration is as follows:

[0023] The event stream corresponding to the vibrating object collected by the event camera is converted into a complex image, and then the complex image is decomposed into multiple sub-bands of different scales and directions. The phase change signal of the vibrating object is calculated based on the phase information of each sub-band, and the vibration frequency of the vibrating object is determined based on the phase change signal.

[0024] Further, the method of observing the flow field is as follows:

[0025] A sheet light source is used to illuminate the moving particles in the flow field to be measured, and the event data caused by the particle movement is recorded by an event camera. The event data is then processed, and the speed and movement direction of the particles are inferred using a velocity estimation algorithm based on the event data. Furthermore, real-time extraction and analysis of flow field features are achieved through real-time extracted data features.

[0026] Furthermore, before observing the flow field, the event camera is configured to obtain appropriate photosensitive elements and microsecond time resolution.

[0027] Furthermore, velocity estimation algorithms based on event data include local contrast maximization or sum correlation methods, and data features extracted in real time include velocity fields and vortex structures.

[0028] Furthermore, fluid-solid image segmentation includes:

[0029] According to the second color, the image transmitted back by the event camera is subjected to a first segmentation process, and only the image area with the second color, that is, the identification plate area, is retained;

[0030] A second segmentation process is then performed based on the first color, that is, solid vibration is observed based on the area of ​​the first color, and the flow field is observed based on the remaining part of the image.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] The fluid-solid coupling vibration full-field measurement device and method based on the event camera of the present invention combines the high speed and high sensitivity of the event camera, and realizes the full-field measurement of the flow field and the solid structure vibration at the same time. By combining the event camera with the flow field measurement technology, the high-precision measurement of the solid structure vibration in the flow field and the flow field itself and the coupling of data can be realized, so as to have a deeper understanding of the complex characteristics of the fluid-solid coupling vibration, as follows:

[0033] 1) The present invention can fully synchronously measure the fluid characteristics and solid vibration characteristics, solving the data coupling problem caused by setting up multiple common sensors to measure the flow field and solid vibration separately.

[0034] 2) Compared with the single-point measurement of ordinary sensor sampling, the present invention can measure the flow field and solid vibration characteristics in the entire spatial field.

[0035] 3) The present invention can directly obtain the amplitude, reduce the system error caused by the indirect measurement method, and has high measurement accuracy.

[0036] 4) The flow field characteristics observed by the present invention can directly obtain the overall rather than local characteristics of the flow field, as well as the flow direction and velocity of the flow field, with comprehensive information and high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic structural diagram of a fluid-solid coupling vibration full-field measurement device based on an event camera of the present invention;

[0038] Figure 2 It is a working schematic diagram of the fluid-solid coupling vibration full-field measurement device based on the event camera of the present invention;

[0039] Figure 3 This is a flow chart of the full-field measurement method of fluid-structure coupling vibration based on an event camera of the present invention;

[0040] Figure 4 It is a flow chart of solid vibration measurement of the present invention;

[0041] Figure 5 It is a flow field measurement algorithm block diagram of the present invention;

[0042] Figure 6 This is a block diagram of the image segmentation algorithm of the present invention.

[0043] In the figure: 1. Sheet light source; 2. Transparent glass box; 3. Marking plate; 4. Fixing spring; 5. Solid to be measured; 6. Scattering light source; 7. Event camera. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0045] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0046] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0047] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0049] The present invention discloses a full-field measurement device and method for fluid-solid coupling vibration based on an event camera. Based on the light intensity perception principle of the event camera, the vibration and flow field characteristics can be measured simultaneously. The full-field measurement method for fluid-solid coupling vibration based on an event camera combines the high speed and high sensitivity of the event camera to achieve full-field measurement of the flow field and solid structure vibration at the same time. By combining the event camera with the flow field measurement technology, high-precision measurement of the solid structure vibration in the flow field and the flow field itself as well as data coupling can be achieved, thereby achieving a deeper understanding of the complex characteristics of fluid-solid coupling vibration and providing important data support for engineering design and scientific research.

[0050] like Figure 1 and Figure 3As shown, the fluid-solid coupling vibration full-field measurement method based on the event camera of the present invention works as follows: A. Arrange the model. B. Load the flow field. C. Illuminate with a sheet light source and a scattered light source. D. The event camera acquires an image. E. The algorithm performs image segmentation on the acquired image. F. After the image segmentation, the image is handed over to two computing systems respectively, and the solid vibration characteristics and the fluid characteristics are analyzed respectively. The vibration information is recorded using a method for observing solid vibration, and the flow field characteristic information is recorded using a method for observing the flow field.

[0051] In order to visualize the flow field characteristics, particle seeding is required so that the flow field carries particles and the flow field characteristic information is reflected through the movement of particles.

[0052] like Figure 1 and Figure 2 As shown, the fluid-solid coupling vibration full-field measurement method based on the event camera of the present invention, an experimental device consists of a sheet light source 1, a transparent glass box 2, an identification plate 3, a fixed spring 4, a solid to be measured 5, a scattered light source 6 and an event camera 7.

[0053] A solid to be tested is fixed inside the transparent glass box 2 by a fixing spring 4. A sheet light source 1 is used to illuminate from above the water tank, and a scattered light source 6 is used to illuminate from the front of the water tank. An event camera 7 is placed in front of the water tank. There is an identification plate 3 at the rear of the water tank to identify the flow field to be tested, and the side of the solid to be tested facing the event camera 7 is marked red.

[0054] It should be noted that a sheet light source 1 can also be arranged below the water tank to simultaneously observe the flow fields on both the upper and lower surfaces of the solid to be measured. The fixing spring 4 can be replaced according to actual needs to make the solid to be measured conform to the actual installation situation.

[0055] Of course, this embodiment is described by taking the water flow field as an example, and it should be understood that the present invention is also applicable to other flow fields, such as wind flow fields, etc.

[0056] In some embodiments, a method for observing solid vibrations, such as Figure 4 As shown. It is illuminated by a scattered light source in the same direction as the event camera. First, the event stream corresponding to the vibrating object is collected by the event camera in front of the water tank, and then the event stream corresponding to the vibrating object collected by the event camera is converted into a complex image, and then the complex image is decomposed into multiple sub-bands of different scales and directions, and then the phase change signal of the vibrating object is calculated in combination with the phase information of each sub-band, and then the vibration frequency of the vibrating object is determined according to the phase change signal.

[0057] In some embodiments, a method for observing a flow field, such as Figure 5As shown. First, use a sheet light source to illuminate an area, and use the event camera in front of the water tank to observe the illuminated area within the identification plate. The steps of using an event camera to observe the real-time characteristics of the flow field include: configuring the event camera to obtain appropriate photosensitive elements and microsecond time resolution, setting a continuously running laser light sheet to illuminate the particles in the flow field, and recording event data caused by particle movement. The event data is then processed, and the speed and direction of movement of the particles are inferred using a velocity estimation algorithm based on event data, such as local contrast maximization or sum correlation method. Furthermore, through real-time extracted data features, such as velocity field, vortex structure, etc., real-time extraction and analysis of flow field features can be achieved. Finally, the extracted real-time features are presented through data visualization technology.

[0058] This method provides a new way to monitor flow field characteristics in high resolution and real time for fluid mechanics research and applications.

[0059] like Figure 6 As shown, the image segmentation algorithm is used to segment the acquired event camera image, and the marking method is to use an identification plate and paint the side of the solid to be tested facing the camera red. In this embodiment, the identification plate uses a white background.

[0060] Image segmentation is an algorithm that uses visual recognition. The algorithm first cuts the image sent back by the event camera according to the signboard, and retains the image with the background color of the signboard. The first step is to segment the area to be identified based on the signboard.

[0061] The second segmentation process is performed. The vibrating solid is painted red on the side facing the event camera, and the solid vibration process is observed based on the red part, and the flow field is observed based on the remaining segmented images. The second time is to perform fluid-solid segmentation based on the red part.

[0062] After the fluid-solid segmentation is completed, the solid vibration information is recorded by using the solid vibration observation method, and the flow field characteristic information is recorded by using the flow field observation method.

[0063] In summary, the present invention can completely synchronize the measurement of fluid characteristics and solid vibration characteristics, solving the data coupling problem caused by setting up multiple ordinary sensors to measure the flow field and solid vibration separately. Compared with the single-point measurement of ordinary sensor sampling, this method can measure the flow field and solid vibration characteristics in the entire spatial field. This method can also directly obtain the amplitude size, reduce the systematic error caused by the indirect measurement method, and have high measurement accuracy. This method can directly obtain the characteristics of the entire flow field rather than the local area. Observing the flow field characteristics can directly obtain the flow direction and velocity of the flow field, and the information is comprehensive and accurate.

[0064] It should be noted that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0065] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0066] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A full-field measurement device for fluid-structure coupling vibration based on an event camera, characterized in that: The device comprises a transparent box, a solid to be measured, a flow field to be measured, an event camera, a marking plate, a scattering light source and a sheet light source; The solid to be tested is placed inside the transparent box; The flow field to be measured is used to carry particles to flow through the solid to be measured; The event camera is located in front of the transparent box, and a first color is set on a side of the solid to be tested facing the event camera; The identification plate is located behind the transparent box and is set to a second color, and is used to identify the flow field to be measured; The scattered light source is located in front of the transparent box and is used to illuminate the solid to be tested; The sheet light source is used to illuminate the moving particles in the flow field to be measured; The flow field to be measured flows through the solid to be measured, causing fluid-solid coupling vibration. The event camera collects event flow images, and performs fluid-solid image segmentation according to the first color and the second color. Finally, solid vibration characteristics and flow field characteristics are respectively obtained based on the segmented images. The method for obtaining the solid vibration characteristics includes: converting the event stream corresponding to the vibrating object collected by the event camera into a complex image, decomposing the complex image into a plurality of sub-bands of different scales and directions, calculating the phase change signal of the vibrating object in combination with the phase information of each sub-band, and determining the vibration frequency of the vibrating object according to the phase change signal; The method for obtaining flow field characteristics includes: using a sheet light source to illuminate moving particles in the flow field to be measured, and recording event data caused by the movement of particles through an event camera; then processing the event data, and using a velocity estimation algorithm based on the event data to infer the velocity and movement direction of the particles; and realizing real-time extraction and analysis of flow field characteristics through real-time extracted data features.

2. The fluid-structure coupling vibration full-field measurement device based on event camera according to claim 1 is characterized in that: The first color is red and the second color is white.

3. The fluid-structure coupling vibration full-field measurement device based on event camera according to claim 1 is characterized in that: The sheet light source is a laser light sheet.

4. The fluid-structure coupling vibration full-field measurement device based on event camera according to claim 1 is characterized in that: The device also includes a fixed spring; the solid to be tested is arranged inside the transparent box through the fixed spring.

5. A full-field measurement method of fluid-structure coupling vibration based on an event camera, characterized in that: The fluid-structure coupling vibration full-field measurement device based on an event camera as described in any one of claims 1 to 4 comprises: Turn on the scattered light source and the sheet light source, and make the flow field to be measured flow through the solid to be measured; The event camera collects event stream images and performs stream-solid image segmentation according to the first color and the second color; Based on the segmented images, the solid vibration characteristics and flow field characteristics are respectively obtained, the solid vibration information is recorded using the solid vibration observation method, and the flow field characteristic information is recorded using the flow field observation method.

6. The full-field measurement method of fluid-structure coupling vibration based on event camera according to claim 5 is characterized in that: The method for observing the vibration of solid is as follows: The event stream corresponding to the vibrating object collected by the event camera is converted into a complex image, and then the complex image is decomposed into multiple sub-bands of different scales and directions. The phase change signal of the vibrating object is calculated based on the phase information of each sub-band, and the vibration frequency of the vibrating object is determined based on the phase change signal.

7. The full-field measurement method of fluid-structure coupling vibration based on event camera according to claim 5 is characterized in that: The method of observing the flow field is as follows: A sheet light source is used to illuminate the moving particles in the flow field to be measured, and the event data caused by the particle movement is recorded by an event camera. The event data is then processed, and the speed and movement direction of the particles are inferred using a velocity estimation algorithm based on the event data. Furthermore, real-time extraction and analysis of flow field features are achieved through real-time extracted data features.

8. The full-field measurement method of fluid-structure coupling vibration based on event camera according to claim 7 is characterized in that: Before observing the flow field, the event camera is configured to obtain appropriate photosensitive elements and microsecond time resolution.

9. The full-field measurement method of fluid-structure coupling vibration based on event camera according to claim 7 is characterized in that: Velocity estimation algorithms based on event data include local contrast maximization or sum correlation methods, and data features extracted in real time include velocity fields and vortex structures.

10. The full-field measurement method of fluid-structure coupling vibration based on event camera according to claim 5, characterized in that: Fluid-solid image segmentation includes: According to the second color, the image transmitted back by the event camera is subjected to a first segmentation process, and only the image area with the second color, that is, the identification plate area, is retained; A second segmentation process is then performed based on the first color, that is, solid vibration is observed based on the area of ​​the first color, and the flow field is observed based on the remaining part of the image.

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