Visual bionic whisker type water flow detection device and method

Abstract

The invention provides a visual bionic whisker type water flow detection device and method. The device comprises a target disc top cover, a rigid whisker, a flexible film target disc, a target disc base, a partition plate, a visual field expanding cylinder, an annular light source, a camera and a base, and the rigid whisker is vertically connected to the center of the flexible film target disc and used for directly sensing water flow information; the flexible film target disc is used for indirectly acquiring water flow information; the target disc top cover and the target disc base are used for fixing the flexible film target disc; when the water flow acts on the rigid whisker, the rigid whisker can drive the flexible film target disc to deflect and deform, the distance between adjacent concentric circles in the direction with the maximum deformation degree and one direction perpendicular to the direction with the maximum deformation degree reflects the speed of the water flow in the horizontal direction and the speed of the water flow in the vertical direction respectively, and therefore water flow size and direction judgment is achieved. The visual touch technology is used for three-dimensional water flow detection, and the device has the outstanding advantages of being simple in structure, not affected by hydrostatic pressure and electromagnetic interference and the like.

Description

Technical Field

[0001] The present invention relates to the technical fields of machine vision, image processing and visual-tactile sensor, and in particular to a visual bionic tentacle-type water flow detection device and method. Background Art

[0002] Water flow sensing has a wide range of applications in many fields. For example, when an underwater robot is navigating and operating, by monitoring changes in water flow, the underwater robot's posture and control system can be adjusted in real time to maintain its stability and good control performance. In marine engineering design and construction, understanding underwater flow velocity and direction and other information is crucial to ensuring the stability and feasibility of the project. In the field of marine energy development (such as tidal energy, ocean current energy, etc.), it is necessary to accurately understand the underwater flow velocity and direction in order to determine the optimal energy collection location and equipment layout. At present, typical underwater flow velocity and direction detection methods mainly include: acoustic, optical and magnetic, among which:

[0003] Acoustic underwater flow velocity and direction detection technology is the main detection method at present, mainly including sonar, acoustic guidance and networked underwater acoustic detection. Its working principle is to detect underwater flow velocity and direction through the interaction between the propagation of sound wave signals in water and the target or obstacle. The general underwater acoustic system consists of a transmitter and a receiver. The transmitter sends out sound wave signals, which propagate in the water and interact with the target or obstacle. When the sound wave signal encounters the target or obstacle, part of the sound wave will be reflected back and received by the receiver. Therefore, by analyzing the received sound wave signal, the direction and speed of the water flow at this time can be obtained. However, this method has certain limitations, because the sound wave will encounter multiple reflections and scattering during the propagation time underwater, resulting in multiple reflections and interference of the signal on the propagation path, thereby producing a multipath effect. This will make the received sound wave signal complicated, making it difficult to accurately separate the signal reflected by the target or obstacle, affecting the accurate measurement of flow velocity and direction. In addition, the marine environment itself has complex noise characteristics, such as waves and currents, which will interfere with the propagation and reception of sound wave signals. Finally, acoustic water flow detection technology must rely on additional equipment, such as a transmitter for emitting sound wave signals and a receiver for receiving reflected signals. The detection process is complicated and cannot be used for real-time self-detection by the robot.

[0004] The optical underwater flow velocity and direction detection method mainly uses laser underwater detection systems and laser radars. Its working principle is that when the laser emits a pulsed laser beam into the underwater environment, the beam will scatter with particles, bubbles and dissolved substances in the water. At this time, a receiver can be placed in an appropriate position to receive the scattered light signal. Finally, the current flow velocity can be analyzed by analyzing the frequency shift and intensity of the scattered light signal. However, the optical underwater flow velocity detection method has certain requirements for the transparency of the water body. In turbid or highly absorbent water bodies, the propagation distance of light will be limited. In addition, optical water flow detection technology requires the use of additional equipment, such as: a transmitter for emitting laser beams and a receiver for receiving scattered light signals, and it is also impossible to achieve self-real-time detection.

[0005] The magnetic underwater flow velocity and flow direction detection technology uses the measurement of the magnetic field distribution in the water flow to detect the water flow velocity and flow rate. The principle of this technology is to place devices such as magnetic fluid meters or magnetic induction flow meters in the water flow, and use the magnetic field disturbances generated by charged particles in the water to affect the output signal of the magnetic sensor. By analyzing and processing these signals, parameters such as the speed and flow of the water flow can be calculated. However, this method has certain limitations. For example, the strength of the magnetic field will weaken with the increase of distance. Therefore, in a long distance and deep water environment, the strength of the magnetic field may become very weak or undetectable. Therefore, the application range and depth of this method are limited by the attenuation of the magnetic field and the propagation distance. In addition, there may be other magnetic interference sources in the water, such as metal structures or other underwater equipment, which may affect the measurement accuracy of the magnetic sensor. Finally, magnetic water flow detection usually requires the use of additional equipment, such as magnetic field sensors and supporting circuits or data acquisition systems, to achieve accurate water flow detection.

[0006] In recent years, water flow detection has adopted piezoelectric and piezoresistive sensors based on bionic whiskers, among which:

[0007] Piezoresistive sensors use the change in resistance at both ends of a piezoresistive element under the action of water flow to achieve detection. They have the advantages of high sensitivity, high frequency response, and low power consumption. However, the detection accuracy of piezoresistive sensors is greatly affected by temperature changes. In addition, piezoresistive whisker sensors are also affected by static pressure during water flow detection, causing the output signal of the sensor to be offset or distorted, thereby affecting the accurate measurement of water flow velocity.

[0008] Piezoelectric sensors use the change in voltage signals generated by piezoelectric materials under the action of water flow to achieve detection. They have the advantages of fast response time, autonomous water flow detection, and simple structure. However, this type of sensor is not suitable for deep water conditions. When the sensor is deployed in a deep water environment, the piezoelectric material in the sensor will be subjected to higher pressure, exceeding its tolerance range, causing the material to rupture or damage. In addition, when piezoelectric sensors are used for water flow detection, static pressure will also affect the output signal of the sensor, causing signal offset or distortion. Summary of the invention

[0009] According to the above-mentioned problems of the traditional water flow detection method, such as the expensive measuring instrument, the inability to be used for self-detection of a single robot, the complex system, and the inability to achieve three-dimensional water flow detection, a visual bionic tentacle-type water flow detection device and method are provided. The present invention uses visual tactile technology for three-dimensional water flow detection, and has outstanding advantages such as simple structure, low manufacturing cost, and no influence of hydrostatic pressure.

[0010] The technical means adopted by the present invention are as follows:

[0011] A visual bionic tentacle-type water flow detection device comprises: a target plate top cover, a rigid tentacle, a flexible film target plate, a target plate base, a partition, a field of view expansion tube, a ring light source, a camera and a base, wherein:

[0012] The rigid tentacles are vertically connected to the center of the flexible film target plate and are used to directly sense water flow information. When water flows through the rigid tentacles, the rigid tentacles are deflected to a certain extent.

[0013] The flexible film target plate is used to indirectly obtain water flow information. When the rigid tentacles are deflected to a certain extent, the flexible film target plate is driven to deform.

[0014] The target plate top cover and the target plate base are used to fix the flexible film target plate;

[0015] The partition is arranged directly below the target plate base and is used to isolate the camera and the annular light source to prevent water from entering;

[0016] The field of view expansion tube is arranged below the partition and in the middle of the flexible film target plate, the annular light source and the camera, so as to increase the distance between the flexible film target plate and the camera, thereby increasing the imaging field of view;

[0017] The annular light source is arranged below the field of view expansion tube and is used to provide illumination;

[0018] The camera and the base are arranged below the annular light source and are used to collect images of the flexible film target plate;

[0019] When water flow acts on the rigid tentacles, the rigid tentacles will cause the flexible film target to deflect and deform. The distance between adjacent concentric circles in the direction of maximum deformation and in one of the directions perpendicular to it reflects the horizontal and vertical speeds of the water flow, respectively, thereby realizing the determination of the size and direction of the water flow.

[0020] Furthermore, a plurality of concentric circular channels are arranged on the bottom surface of the flexible film target plate.

[0021] Furthermore, a through hole is provided on the side wall of the target plate base for balancing the water pressure on the upper and lower sides of the flexible film target plate.

[0022] Furthermore, a layer of spray material consisting of titanium dioxide, colored silica gel and diluted solution is sprayed on the top of the flexible film target plate for shading.

[0023] Furthermore, the partition is made of transparent material.

[0024] The present invention also provides a method for detecting the direction and velocity of a three-dimensional water flow based on the visual bionic tentacle-type water flow detection device, comprising:

[0025] S1. Encapsulating the visual bionic tentacle-type water flow detection device in water, exposing the rigid tentacles to the water, and causing the rigid tentacles to deflect when the water flows through the rigid tentacles, thereby causing the flexible film target plate connected to the rigid tentacles to deform;

[0026] S2. When the flexible film target is not deformed, take a picture of the flexible film target, and use image processing technology to obtain the contour of the concentric circular channel on the flexible film target and calculate the distance X between adjacent concentric circles;

[0027] S3. After the flexible film target plate is deformed, the deformation direction is divided into four directions, namely, the end with the largest deformation degree of the flexible film target plate, the largest end is named as the large end, the spacing is recorded as X1, the direction opposite to the largest end is defined as the small end, the spacing is recorded as X2, and the other two ends perpendicular to the straight line where the large end and the small end are located are defined as the upper end and the lower end, and the spacings are recorded as Y1 and Y2 respectively;

[0028] S4, photographing an image of the deformed flexible film target and calculating the spacings in four directions on adjacent concentric circles;

[0029] S5. When X1=X2, it means that the water flow direction is perpendicular to the flexible film target plate; when X1>X2, and Y1=Y2=X, it means that the water flow direction is parallel to the flexible film target plate; when X1>X2, and Y1=Y2>X, the water flow is three-dimensional.

[0030] Furthermore, step S2 specifically includes:

[0031] S21, converting the original image captured by the camera into a grayscale image;

[0032] S22, using Gaussian filtering to remove image noise, using the Otsu algorithm (OTSU) to perform automated threshold segmentation, segmenting the image into foreground and background, enhancing image visibility and facilitating feature extraction;

[0033] S23, extracting the concentric circle contours using an active contour model algorithm (ACM);

[0034] S24. Calculate the distance between adjacent concentric circles, denoted as X.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] 1. The present invention provides a visual bionic tentacle-type water flow detection device, which is inspired by animal tentacles and combines bionic tentacles with visual-tactile technology for three-dimensional water flow detection. It has the outstanding advantages of simple structure, low manufacturing cost, and no underwater electromagnetic interference.

[0037] 2. In the sensor provided by the present invention, a through hole is provided on the side wall of the target base, which can maintain the balance of internal and external pressures. Compared with piezoelectric sensors and piezoresistive sensors, it is not affected by hydrostatic pressure.

[0038] 3. The present invention provides a three-dimensional water flow direction and flow velocity detection method based on a visual bionic tentacle-type water flow detection device, which can detect the flow velocity in real time and determine the three-dimensional flow direction through simple image processing, without relying on traditional complex calculation methods (three-dimensional reconstruction or deep learning). Compared with existing traditional methods, the method provided by the present invention has a smaller amount of calculation and is less time-consuming, and has higher practicality and efficiency.

[0039] 4. The present invention provides a visual bionic tentacle-type water flow detection device, which can achieve high-precision water flow detection through the distance between the innermost adjacent concentric circles on the flexible elastic film (the innermost circle is marked as the first circle, and the distance between the first circle and the second circle of concentric circles), and achieve a large flow detection range through the distance between the outer adjacent concentric circles of the flexible elastic film. However, it is difficult for traditional sensors to achieve both high precision and a large detection range.

[0040] Based on the above reasons, the present invention can be widely promoted in the field of underwater sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0042] Figure 1 This is an overall schematic diagram of a visual bionic tentacle-type water flow detection device of the present invention.

[0043] Figure 2 This is a schematic diagram of the exploded view of a visual bionic tentacle-type water flow detection device of the present invention.

[0044] Figure 3 This is a schematic diagram of the integration of the rigid tentacles and the flexible film target plate of the present invention.

[0045] Figure 4 The figure is a flow chart of the method for detecting the direction and velocity of three-dimensional water flow according to the present invention.

[0046] In the figure: 1. Target plate top cover; 2. Rigid tentacles; 3. Flexible film target plate; 4. Target plate base; 5. Partition; 6. Field of view expansion tube; 7. Ring light source; 8. Camera; 9. Base. DETAILED DESCRIPTION

[0047] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in 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. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0050] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0051] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0052] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0053] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0054] like Figure 1 ,2 As shown, the present invention provides a visual bionic tentacle-type water flow detection device, comprising: a target plate top cover 1, a rigid tentacle 2, a flexible film target plate 3, a target plate base 4, a partition 5, a field of view expansion tube 6, a ring light source 7, a camera 8 and a base 9, wherein:

[0055] The rigid tentacle 2 is vertically connected to the center of the flexible film target plate 3 and is used to directly sense water flow information. When water flows through the rigid tentacle 2, the rigid tentacle 2 is deflected to a certain extent.

[0056] The flexible film target plate 3 is used to indirectly obtain water flow information (flow velocity and flow direction). When the rigid tentacles 2 are deflected to a certain extent, the flexible film target plate 3 is deformed; Figure 3 FIG. 2 is a schematic diagram showing the integration of the rigid tentacle 2 and the flexible film target plate 3 .

[0057] The target plate top cover 1 and the target plate base 4 are used to fix the flexible film target plate 3;

[0058] The partition 5 is arranged directly below the target base 4 and is used to isolate the camera 8 and the annular light source 7 to prevent water from entering;

[0059] The field of view expansion tube 6 is arranged below the partition 5 and in the middle of the flexible film target plate 3, the annular light source 7 and the camera 8. Figure 2 As shown, the top of the field of view expansion tube 6 is connected to the partition 5, and the bottom is connected to the ring light source 7 and the camera 8. On the one hand, it plays a supporting role, and on the other hand, it increases the distance between the flexible film target plate 3 and the camera 8, thereby increasing the imaging field of view and better capturing the overall picture.

[0060] The annular light source 7 is arranged below the field of view expansion tube 6 and is used to provide illumination;

[0061] The camera 8 and the base 9 are connected to each other and are arranged below the annular light source 7 to collect images of the flexible film target plate 3;

[0062] When the water flow acts on the rigid tentacle 2, the rigid tentacle 2 will cause the flexible film target plate 3 to deflect and deform. The distance between adjacent concentric circles in the direction of maximum deformation and in one of the directions perpendicular to it respectively reflects the horizontal and vertical speeds of the water flow, thereby realizing the determination of the size and direction of the water flow.

[0063] When specifically implemented, as a preferred embodiment of the present invention, Figure 2 As shown, the bottom surface of the flexible film target plate 3 is provided with a plurality of concentric circular channels (filled with a mixture of 40 um aluminum powder and silica gel).

[0064] When specifically implemented, as a preferred embodiment of the present invention, Figure 2 As shown, a through hole (diameter 10 mm) is provided on the side wall of the target plate base (4) for balancing the water pressure on the upper and lower sides of the flexible film target plate 3.

[0065] When specifically implemented, as a preferred embodiment of the present invention, Figure 2 As shown, a layer of spray material consisting of titanium dioxide, colored silica gel and diluted solution is sprayed on the top of the flexible film target plate 3 for shading.

[0066] like Figure 4 As shown, the embodiment of the present invention also provides a method for detecting the direction and velocity of a three-dimensional water flow based on the visual bionic tentacle-type water flow detection device, comprising:

[0067] S1, encapsulating the visual bionic tentacle-type water flow detection device into water, exposing the rigid tentacle 2 to the water, and when the water flows through the rigid tentacle 2, the rigid tentacle 2 is deflected, thereby causing the flexible film target plate 3 connected to the rigid tentacle 2 to deform;

[0068] S2, when the flexible film target plate 3 is not deformed, taking a picture of the flexible film target plate 3, and using image processing technology to obtain the contour of the concentric circular channel on the flexible film target plate 3 and calculate the distance X between adjacent concentric circles;

[0069] S3, after the flexible film target plate 3 is deformed, the deformation direction is divided into four directions, namely, the end with the largest deformation degree of the flexible film target plate 3, the largest end is named as the large end, the spacing is recorded as X1, the direction opposite to the largest end is defined as the small end, the spacing is recorded as X2, and the other two ends perpendicular to the straight line where the large end and the small end are located are defined as the upper end and the lower end, and the spacings are recorded as Y1 and Y2 respectively;

[0070] S4, photographing the deformed image of the flexible film target plate 3 and calculating the spacings in four directions on adjacent concentric circles;

[0071] S5. When X1=X2, it means that the water flow direction is perpendicular to the flexible film target plate 3; when X1>X2, and Y1=Y2=X, it means that the water flow direction is parallel to the flexible film target plate 3; when X1>X2, and Y1=Y2>X, the water flow is three-dimensional.

[0072] In specific implementation, as a preferred embodiment of the present invention, step S2 specifically includes:

[0073] S21, converting the original image captured by the camera 8 into a grayscale image;

[0074] S22, using Gaussian filtering to remove image noise, using the Otsu algorithm (OTSU) to perform automated threshold segmentation, segmenting the image into foreground and background, enhancing image visibility and facilitating feature extraction;

[0075] S23, extracting the concentric circle contours using an active contour model algorithm (ACM);

[0076] S24. Calculate the distance between adjacent concentric circles, denoted as X.

[0077] Based on the above, the incoming flow direction can be determined according to the change in the spacing of the four directions of the concentric circles on the flexible film target plate. The magnitude of the water flow is determined by the relationship between the flow velocity and the spacing of the flexible film target plates established by laboratory experiments.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A visual bionic tentacle-type water flow detection device, characterized in that: include: A target plate top cover (1), a rigid tentacles (2), a flexible film target plate (3), a target plate base (4), a partition (5), a field of view expansion tube (6), a ring light source (7), a camera (8) and a base (9), wherein: The rigid tentacle (2) is vertically connected to the center of the flexible film target plate (3) and is used to directly sense water flow information. When water flows through the rigid tentacle (2), the rigid tentacle (2) is deflected to a certain extent. The flexible film target plate (3) is used to indirectly obtain water flow information. When the rigid tentacles (2) are deflected to a certain extent, the flexible film target plate (3) is driven to deform. The target plate top cover (1) and the target plate base (4) are used to fix the flexible film target plate (3); The partition (5) is arranged directly below the target plate base (4) and is used to isolate the camera (8) and the annular light source (7) to prevent water from entering; The field of view expansion tube (6) is arranged below the partition (5) and in the middle of the flexible film target plate (3), the annular light source (7) and the camera (8), so as to increase the distance between the flexible film target plate (3) and the camera (8), thereby increasing the imaging field of view; The annular light source (7) is arranged below the field of view expansion tube (6) and is used to provide illumination; The camera (8) and the base (9) are arranged below the annular light source (7) and are used to collect images of the flexible film target plate (3); When the water flow acts on the rigid tentacles (2), the rigid tentacles (2) will drive the flexible film target plate (3) to deflect and deform, and the distance between adjacent concentric circles in the direction of maximum deformation and in one of the directions perpendicular thereto respectively reflects the speed of the water flow in the horizontal and vertical directions, thereby realizing the determination of the size and direction of the water flow.

2. A visual bionic tentacle-type water flow detection device according to claim 1, characterized in that: The bottom surface of the flexible film target plate (3) is provided with a plurality of concentric circular channels.

3. The visual bionic tentacle-type water flow detection device according to claim 1, characterized in that: The side wall of the target plate base (4) is provided with a through hole for balancing the water pressure on the upper and lower sides of the flexible film target plate (3).

4. The visual bionic tentacle-type water flow detection device according to claim 1, characterized in that: A layer of spray material consisting of titanium dioxide, colored silica gel and a diluted solution is sprayed on the top of the flexible film target plate (3) for shading.

5. The visual bionic tentacle-type water flow detection device according to claim 1, characterized in that: The partition (5) is made of transparent material.

6. A method for detecting the direction and velocity of a three-dimensional water flow based on the visual bionic tentacle-type water flow detection device according to any one of claims 1 to 5, characterized in that: include: S1, encapsulating the visual bionic tentacle-type water flow detection device into water, exposing the rigid tentacle (2) to the water, and causing the rigid tentacle (2) to deflect when the water flow scours the rigid tentacle (2), thereby causing the flexible film target plate (3) connected to the rigid tentacle (2) to deform; S2, when the flexible film target plate (3) is not deformed, taking a picture of the flexible film target plate (3), and using image processing technology to obtain the contour of the concentric circular channels on the flexible film target plate (3) and calculate the distance X between adjacent concentric circles; S3. When the flexible film target plate (3) is deformed, the deformation direction is divided into four directions, namely, the end of the flexible film target plate (3) with the largest deformation degree, the largest end is named as the large end, the distance is recorded as X1, the direction opposite to the largest end is defined as the small end, the distance is recorded as X2, and the other two ends perpendicular to the straight line where the large end and the small end are located are defined as the upper end and the lower end, and the distances are recorded as Y1 and Y2 respectively; S4, photographing an image of the flexible film target plate (3) after deformation and calculating the spacings in four directions on adjacent concentric circles; S5. When X1=X2, it means that the direction of the water flow is perpendicular to the flexible film target plate (3); when X1>X2, and Y1=Y2=X, it means that the direction of the water flow is parallel to the flexible film target plate (3); when X1>X2, and Y1=Y2>X, the water flow is three-dimensional.

7. The method for detecting the direction and velocity of a three-dimensional water flow according to claim 6, characterized in that: Step S2 specifically includes: S21, converting the original image captured by the camera (8) into a grayscale image; S22, using Gaussian filtering to remove image noise, using Otsu algorithm to perform automated threshold segmentation, segmenting the image into foreground and background, enhancing image visibility and facilitating feature extraction; S23, extracting concentric circle contours using an active contour model algorithm; S24. Calculate the distance between adjacent concentric circles, denoted as X.

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