Vision-based motion rope through hole measurement method

Abstract

The invention discloses a vision-based motion rope through hole measurement method, and relates to the technical field of precise measurement such as computer vision and mechanics. In order to solve the technical problem that in the prior art, real-time and accurate measurement of the diameter of a rope in a motion state cannot be realized under the dynamic conditions of stress and motion, the technical scheme provided by the invention is as follows: a motion rope through hole measurement method based on vision is provided. The method comprises the following steps: acquiring deformed images of a rope under different stress conditions; a step of selecting a designated area in the image; processing the specified area to obtain the diameter of the rope; according to the diameter of the rope and real-time tension sensor data, the compression amount and the transmission ratio of the rope in the stress state are obtained. The method further comprises the step of drawing a diameter change curve graph of the rope under different stress conditions. The device is suitable for measuring the diameter of the rope in a motion state.

Description

Technical Field

[0001] The invention relates to the fields of computer vision, mechanics and other precision measurement technologies, and specifically to the precise measurement of the change in rope diameter when the rope is stretched under stress. Background Art

[0002] In the field of modern precision measurement, the measurement of the stress state of ropes has always been an important research topic, especially when the rope is in dynamic motion and tensile deformation, measuring its diameter change is crucial for a variety of engineering applications. Most of the existing rope measurement methods are based on traditional contact measurement methods, such as using calipers, tension sensors and other tools. However, these methods have significant limitations, especially in the following aspects:

[0003] First, the limitations of static measurement. Traditional measuring tools, such as calipers and measuring instruments, are mostly used to measure ropes in a static state. These tools require manual operation, are greatly affected by human errors, and are not suitable for dynamic measurements. For example, when the rope moves at high speed or is stretched and deformed, it is difficult for the caliper to accurately measure the instantaneous diameter, resulting in low measurement efficiency and insufficient reliability. This is particularly evident in industrial production and safety monitoring. For example, in scenarios such as lifting operations, mine safety, and cable bridge monitoring, it is necessary to understand the status of the rope in real time to ensure safety.

[0004] Secondly, the contact measurement method has its shortcomings. Since the rope will deform under dynamic force, friction and sliding may occur on its surface, making it difficult for contact measurement tools to provide accurate measurement data. In addition, contact measurement may cause physical damage to the rope itself, especially in some precision applications, such as maintenance and inspection of high-altitude cables. Such damage may cause serious safety hazards. Therefore, non-contact measurement has become an effective alternative to reduce physical interference with the rope.

[0005] In recent years, computer vision technology has been widely used in the field of industrial inspection. It uses cameras to capture images and analyzes the size and deformation of objects through image processing algorithms. These methods are non-contact, automated, and highly accurate, and have been applied to a variety of measurement scenarios. For example, in production lines, computer vision technology can be used to automatically detect product dimensions and avoid errors caused by manual operations. In addition, the development of image processing technology, such as edge detection, morphological operations, and image segmentation, makes the size measurement of target objects more accurate and efficient. For static objects, computer vision technology has shown significant advantages.

[0006] However, there are still many challenges in existing visual measurement methods for measuring ropes in motion. For example, ropes may be affected by many factors during movement, such as lighting conditions, rapid deformation of ropes, and complexity of surface textures, which can interfere with image clarity and measurement accuracy. In addition, ropes in motion deform dynamically and irregularly due to the influence of sliding friction and tension. A single camera may not be able to fully capture all deformation information, resulting in unstable measurement results.

[0007] Therefore, the existing technology generally has the following technical problems: there is a lack of effective methods for measuring the diameter of the rope in motion, and it is impossible to achieve real-time and accurate measurement of the rope diameter under dynamic conditions of force and motion. Moreover, for environments with changing lighting and complex deformation, the adaptability of the existing visual measurement system is poor and the measurement accuracy is not high. Traditional contact measurement methods are even more difficult to meet the needs of real-time monitoring and high-frequency measurement. Summary of the invention

[0008] In order to solve the technical problem existing in the prior art that the measurement of the rope diameter in the moving state cannot realize the real-time and accurate measurement of the rope diameter under the dynamic conditions of force and movement, the technical solution provided by the present invention is:

[0009] A method for measuring a hole in a moving rope based on vision, the method comprising:

[0010] Steps for collecting images of ropes after deformation under different stress conditions;

[0011] A step of selecting a designated area in the image;

[0012] The step of processing the designated area to obtain the diameter of the rope;

[0013] The step of obtaining the compression amount and transmission ratio of the rope under stress according to the diameter of the rope and the real-time tension sensor data.

[0014] Furthermore, a preferred embodiment is provided, in which different forces on the rope are achieved through a motor, a weight and a pulley.

[0015] Furthermore, a preferred embodiment is provided, wherein the designated area is a portion of the rope near the hole, which is achieved by ROI area selection.

[0016] Furthermore, a preferred embodiment is provided, wherein the processing includes denoising and thresholding processing.

[0017] Furthermore, a preferred embodiment is provided, wherein the diameter of the rope is obtained through the profile of the rope.

[0018] Furthermore, a preferred embodiment is provided, which also includes the step of drawing a diameter variation curve of the rope under different stress conditions.

[0019] Based on the same inventive concept, the present invention also provides a visual-based sports rope hole measurement device, the device comprising:

[0020] A module for collecting images of rope deformation under different stress conditions;

[0021] Selecting a module in a designated area of ​​the image;

[0022] Processing the designated area to obtain a module of the rope diameter;

[0023] According to the diameter of the rope and the real-time tension sensor data, a module for obtaining the compression amount and transmission ratio of the rope under stress is obtained.

[0024] Based on the same inventive concept, the present invention also provides a computer storage medium for storing a computer program, and when the computer reads the computer program, the computer executes the described method.

[0025] Based on the same inventive concept, the present invention also provides a computer, including a processor and a storage medium. When the processor reads a computer program stored in the storage medium, the computer executes the method described.

[0026] Based on the same inventive concept, the present invention also provides a computer program product, which is a computer program. When the computer program is executed, the method described above is implemented.

[0027] Compared with the prior art, the technical solution provided by the present invention is beneficial in that:

[0028] By building a multi-camera based visual measurement platform, we can capture the moving rope from multiple angles. This multi-camera layout can effectively reduce the interference caused by lighting changes and rope deformation, ensuring image stability and measurement accuracy. Compared with the traditional single-camera system, the use of multiple cameras can obtain images from different angles, avoiding the loss of measurement information caused by rope twisting or occlusion, thereby greatly improving the robustness and data integrity of the overall system.

[0029] Using OpenCV and other advanced image processing algorithms, including edge detection, morphological operations and binarization, the ropes in the image are accurately extracted. The use of these algorithms enables the system to effectively separate the boundaries of the ropes in complex backgrounds, reducing the impact of environmental noise on the measurement. Compared with traditional manual visual inspection or simple contact measurement, this computer vision-based processing method can capture tiny deformation details, especially in the process of rope deformation under stress, and the accuracy is greatly improved.

[0030] By introducing a tension sensor to obtain rope force data and combining it with visual measurement results, the system can achieve a comprehensive analysis of the relationship between rope force and diameter change. This method of combining mechanical measurement with visual measurement effectively solves the problem that relying solely on visual measurement may not reflect the internal force state. Compared with traditional measurement methods, this method can conduct a comprehensive analysis of the rope force condition based on real-time monitoring, thereby more accurately predicting the wear and fatigue of the rope, and improving safety and early warning capabilities.

[0031] The combination of dynamic shooting and real-time image processing overcomes the disadvantage of traditional static measurement that cannot cope with deformation during movement. The camera captures the deformation process of the rope under force movement in real time, and combined with the synchronous control of the motor, it ensures the time and space accuracy of the measurement. Compared with static measurement, this real-time measurement method can still maintain high accuracy in high-frequency dynamic changes, providing reliable data support for engineering applications that require accurate understanding of the dynamic characteristics of the rope.

[0032] It is suitable for measuring the diameter of ropes in motion. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Get schematics for rope measurement pictures;

[0034] Figure 2 This is a schematic diagram of rope diameter measurement results;

[0035] Figure 3 Schematic diagram of the image area;

[0036] Figure 4 Schematic diagram of threshold processing;

[0037] Figure 5 It is a schematic diagram of the outline;

[0038] Figure 6 Get a schematic diagram for rope distance and diameter;

[0039] Figure 7 Schematic diagram of the image taken during the test rope;

[0040] Figure 8It is a schematic diagram of the relationship between force transmission ratio, speed and angle;

[0041] Fig. 9 Schematic diagram of the relationship between compression ratio, angle and speed. DETAILED DESCRIPTION

[0042] In order to make the advantages and benefits of the technical solution provided by the present invention more clearly reflected, the technical solution provided by the present invention is now further described in detail with reference to the accompanying drawings, specifically:

[0043] Embodiment 1: This embodiment provides a visual-based method for measuring a hole in a moving rope, the method comprising:

[0044] Steps for collecting images of ropes after deformation under different stress conditions;

[0045] A step of selecting a designated area in the image;

[0046] The step of processing the designated area to obtain the diameter of the rope;

[0047] The step of obtaining the compression amount and transmission ratio of the rope under stress according to the diameter of the rope and the real-time tension sensor data.

[0048] Specific:

[0049] Step 1: Build the rope survey platform

[0050] Establish an experimental platform, including ropes, tension sensors, motors, limit holes, cameras and light sources.

[0051] Detailed description: The first task of building a rope measurement platform is to assemble the various components of the system. Specifically, one end of the rope is connected to the tension sensor and motor, the other end is connected to the weight, and a pulley is used in the middle to guide the movement path of the rope. The camera is installed near the pulley to capture the movement and deformation process of the rope. The limit hole is made of transparent material such as glass to limit the movement trajectory of the rope for better measurement. In addition, a light source is used to provide sufficient brightness for the camera to reduce the interference of shadows and reflections so that the camera can obtain a clear image.

[0052] Step 2: Set camera parameters and shoot

[0053] Set the camera parameters and control the camera to shoot in real time.

[0054] Detailed description: Run the camera shooting program that has been programmed, and adjust the camera parameters according to the experimental conditions, including exposure time, aperture size, focal length, etc. The camera shooting parameters need to be debugged in combination with the lighting conditions to ensure that the image quality is sufficient for subsequent processing. The control program will set the camera shooting time interval to ensure that the state of the rope at different time points in motion can be continuously captured. By setting the automatic shooting function, it is ensured that the rope can be monitored and recorded in real time throughout the entire process of movement, providing data for the next image processing step.

[0055] Step 3: Motor Controls Rope Movement and Synchronizes Shooting

[0056] The motor is started to control the movement of the rope, while the camera takes pictures and outputs image sequences.

[0057] Detailed description: After the motor is started, the motor will drive the weight to rise, causing the rope to deform under force near the limit hole. The weight will then remain for a period of time before falling to the initial position. During this process, the camera continuously captures the deformation of the rope through a preset program. Each frame of the image captured records the current state of the rope, including changes in diameter, deformation, etc. In addition, the tension sensor synchronously records the force data of the rope. The output of this step is a continuous sequence of images and corresponding force data, which provides a basis for subsequent data processing steps.

[0058] Step 4: Image Processing

[0059] The captured images are processed to extract the rope edges and calculate their diameter.

[0060] Detailed description: Image processing is performed using the OpenCV library. First, the image needs to be denoised to reduce the noise introduced by uneven lighting or complex background. After denoising, the image binarization technology is used to distinguish the rope from the background in the image, and only the rope area is retained. After extracting the target area, an edge detection algorithm, such as Canny edge detection, is applied to identify the boundary of the rope to obtain a clear edge contour. Then, through contour extraction, the two edge lines of the rope are obtained, and the shortest distance between the edges is calculated to obtain the diameter of the rope. The entire image processing process needs to consider real-time performance to ensure that the processing speed of each frame of the image can meet the needs of real-time monitoring.

[0061] Step 5: Comprehensive analysis of tension and diameter data

[0062] The rope diameter and tension data are processed comprehensively to perform stress analysis.

[0063] Detailed description: While obtaining the rope diameter, the tension sensor records the rope force information. The two sets of data are combined to analyze the trend of rope diameter changes with force to infer the rope force state and deformation behavior. Data fitting and modeling methods can be used to obtain the relationship curve between diameter and force to help determine the deformation characteristics of the rope under different force conditions. This process can be achieved through programming, and parameters such as force transmission ratio and compression can be calculated. The final analysis results can be used to optimize the use of ropes and improve the accuracy of safety monitoring.

[0064] Step 6: Data storage and further analysis

[0065] The acquired image data, diameter data and force sensor data are stored and analyzed.

[0066] All collected data, including the diameter information and corresponding tension data of each frame, will be stored in a database or file for subsequent analysis and verification. In order to increase universality, ropes of different materials can be tested, including fiber ropes, wire ropes, and rubber ropes, etc., and the accuracy and stability of the system can be verified by comparing the deformation of different types of ropes under the same conditions. Using these data, force simulation and structural reliability analysis can be further performed to provide a scientific basis for the selection and use of ropes in engineering applications.

[0067] In the specific implementation, step 1: build a measurement platform

[0068] Set up a measuring platform to film and measure the rope in motion.

[0069] Detailed description: One end of the rope is connected to a tension sensor and a motor, and the other end is connected to a weight, which is turned through a pulley. The camera is set near the pulley to capture images of the rope's deformation under force. The platform design ensures that the rope will produce obvious deformation when it is under force, which is convenient for subsequent shooting and analysis.

[0070] Step 2: Set the camera parameters and shoot

[0071] Set the camera parameters to ensure clear and accurate shooting.

[0072] Detailed description: Run the camera control program and set the camera parameters such as shooting time and exposure time. Adjust the camera's aperture and focal length to achieve the best imaging effect. Control the camera to take real-time pictures of the rope to obtain deformation images of the rope under different stress states.

[0073] Step 3: Rope Movement and Real-time Image Acquisition

[0074] The rope is forced to move, and corresponding images and sensor data are collected simultaneously.

[0075] Detailed description: Start the motor to drive the rope to drag the weight. During the process, the rope is deformed by force. The camera continuously takes pictures of the moving rope to obtain each frame of the image. During this process, the tension sensor records the force of the rope in real time. The motor drags the weight up and hovers for a period of time before descending to simulate the movement and deformation of the rope in different states.

[0076] Step 4: Image processing and diameter calculation

[0077] The captured images are processed to calculate the diameter of the rope.

[0078] Detailed description: The image acquired by the camera is processed using OpenCV. First, the ROI (region of interest) is selected to ensure that only the rope part near the hole is processed. Next, the image is denoised and thresholded to extract the outline of the rope. The edge data of the rope is obtained through the contour extraction algorithm, and the distance between the two edges is calculated to determine the diameter of the rope. Adaptive thresholding and morphological operations are used to improve the accuracy and stability of the calculation.

[0079] Step 5: Mechanical data analysis and storage

[0080] Analyze the measured data and perform further mechanical calculations and storage.

[0081] Detailed description: Combine the acquired rope diameter data with the real-time tension sensor data to perform mechanical analysis. Calculate the rope compression and transmission ratio under stress, and draw a curve of rope diameter change. Store all measurement data in a file for subsequent detailed analysis and verification.

[0082] Embodiment 2: This embodiment further limits the vision-based method for measuring the hole of a moving rope provided in embodiment 1, and realizes different forces on the rope through a motor, a weight and a pulley.

[0083] Implementation method three: This implementation method further limits the vision-based moving rope through-hole measurement method provided in implementation method one. The designated area is the rope portion near the hole, which is achieved through ROI area selection.

[0084] Embodiment 4: This embodiment further limits the vision-based moving rope hole measurement method provided in embodiment 1, and the processing includes denoising and thresholding processing.

[0085] Embodiment 5: This embodiment further limits the vision-based method for measuring the hole of a moving rope provided in Embodiment 1, and obtains the diameter of the rope through the outline of the rope.

[0086] Embodiment 6: This embodiment further limits the visual-based method for measuring the hole of a moving rope provided in Embodiment 1, and further includes the step of drawing a diameter variation curve of the rope under different stress conditions.

[0087] Embodiment 7: This embodiment provides a visual-based motion rope hole measurement device, the device comprising:

[0088] A module for collecting images of rope deformation under different stress conditions;

[0089] Selecting a module in a designated area of ​​the image;

[0090] Processing the designated area to obtain a module of the rope diameter;

[0091] According to the diameter of the rope and the real-time tension sensor data, a module for obtaining the compression amount and transmission ratio of the rope under stress is obtained.

[0092] Embodiment 8: This embodiment provides a computer storage medium for storing a computer program. When the computer reads the computer program, the computer executes the method provided in embodiment 1.

[0093] Embodiment 9: This embodiment provides a computer, including a processor and a storage medium. When the processor reads a computer program stored in the storage medium, the computer executes the method provided in embodiment 1.

[0094] Embodiment 10: This embodiment provides a computer program product, which is a computer program. When the computer program is executed, the method provided in embodiment 1 is implemented.

[0095] Implementation Method XI: Combination Figure 1-9 This embodiment is described. This embodiment further clearly and completely describes the technical solution provided above through specific examples. Specifically:

[0096] In the prior art, the measurement of ropes and related forces mainly remains at the stage of measuring static ropes, and there is no good method to measure the rope diameter for ropes in motion and deformation. For some problems, it is necessary to perform real-time force analysis and real-time measurement on the ropes, which cannot be achieved in traditional measurements. Therefore, in order to solve the above problems and conduct real-time monitoring and force analysis on the moving ropes, it is necessary to propose a rope measurement solution based on external sensors, and at the same time, based on the mechanical properties of the rope itself, indirectly analyze the rope's force and other related characteristics to achieve real-time detection of the rope.

[0097] When the rope moves in the hole, under the action of the contact surface pressure, the size of the rope in the contact part of the rope hole in the pressure direction is smaller than the diameter of the rope section outside the rope hole. Therefore, when the rope and the rope hole have sliding friction, the material at the contact position of the rope is squeezed and pushed to both sides by the hole. This phenomenon is similar to the plowing effect in mechanical processing. To verify the corresponding conclusion, this experiment simulates the movement state of the rope when passing through the hole, and obtains the deformation near the rope hole by visual photography.

[0098] The steps of the vision-based sports rope measurement method are as follows:

[0099] Step 1: Build a rope measurement platform. As shown in the figure, one end of the rope is connected to the tension sensor and the motor, and the other end is connected to the weight. The rope is turned by a pulley in the middle. The camera is set up near the pulley to capture the image of the rope deformation.

[0100] Step 2, run the programmed camera program, modify the required camera parameters, adjust the camera's aperture and focal length, change the exposure time and shooting time, and start the camera to take pictures;

[0101] Step 3, turn on the motor, so that the motor drags the rope to move, and the camera continues to take pictures of the rope. The motor drags the weight up, and after hovering for a period of time, the weight is lowered. Each frame of the image obtained by the camera is processed and the rope diameter is output. At the same time, the tension sensor outputs the tension data at this time;

[0102] The specific method for calculating the diameter is as follows:

[0103] In this experiment, it is believed that the edge contour of the part where the rope fits the hole remains unchanged. Using OpenCV to process the image, first select the ROI area of ​​the image and select the area near the hole for processing. Figure 3 As shown;

[0104] Then, the image is denoised and thresholded to keep only the rope part, e.g. Figure 4 As shown;

[0105] According to the binary image obtained by threshold processing, the image is contour extracted to obtain two contours on both sides of the rope. The obtained contour map is as follows Figure 5 As shown;

[0106] The two extracted contours can be clearly seen in the contour map. By finding the two closest points in the two contours, the pixel positions of the two points corresponding to the distance can be obtained. This method uses traversal of all pixel points on the contour to obtain. Since the rope in contact with the pulley is, the contour does not change approximately during the entire movement process, the normal vector corresponding to the point can be obtained through the upper arc local contour, and it is assumed that the normal vector does not change during the entire movement process. Through this normal vector, the distance between the two points of the rope in other pictures is calculated to obtain the diameter of the relatively stable rope, such as Figure 6 shown.

[0107] Step 4: Store the acquired rope diameter information, tension sensor information, etc. in a file for mechanical analysis.

[0108] Data processing:

[0109] In order to increase the universal applicability, different types of ropes were photographed and measured, and different materials were tested. Figure 7 shown.

[0110] Among them, a large amount of data detection was carried out on the fiber rope. The weight of the weight was 5kg and the original diameter of the rope was 2.5mm. The tension and weight of the weight were calculated to obtain the force transmission ratio during movement. At the same time, the rope compression was obtained from the original length and change of the rope. According to the obtained data, the change diagram of the rope diameter change was drawn as shown in the figure below: Figure 8 , 9 shown.

[0111] The technical solution provided by the present invention is further described in detail above through several specific implementation modes in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the several specific implementation modes described above are not intended to be used as limitations on the present invention. Any reasonable modification and improvement of the present invention, combination of implementation modes and equivalent substitution within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A visual-based method for measuring the hole of a moving rope, characterized in that: Methods include: Steps for collecting images of ropes after deformation under different stress conditions; A step of selecting a designated area in the image; The step of processing the designated area to obtain the diameter of the rope; The step of obtaining the compression amount and transmission ratio of the rope under stress according to the diameter of the rope and the real-time tension sensor data.

2. A visual-based method for measuring the hole of a sports rope according to claim 1, characterized in that: Different forces on the rope are achieved through motors, weights and pulleys.

3. The visual-based method for measuring the hole of a sports rope according to claim 1, characterized in that: The designated area is the rope portion near the hole, which is achieved by ROI area selection.

4. The visual-based method for measuring the hole of a sports rope according to claim 1, characterized in that: The processing includes denoising and thresholding.

5. The visual-based method for measuring the hole of a sports rope according to claim 1, characterized in that: From the profile of the rope, the diameter of the rope is obtained.

6. The visual-based method for measuring the hole of a sports rope according to claim 1, characterized in that: The method also includes the step of drawing a diameter variation curve diagram of the rope under different stress conditions.

7. A visual-based sports rope hole measurement device, characterized in that: The device includes: A module for collecting images of rope deformation under different stress conditions; Selecting a module in a designated area of ​​the image; Processing the designated area to obtain a module of the rope diameter; According to the diameter of the rope and the real-time tension sensor data, a module for obtaining the compression amount and transmission ratio of the rope under stress is obtained.

8. A computer storage medium for storing a computing program, characterized in that: When the computer reads the computer program, the computer executes the method of claim 1.

9. A computer, comprising a processor and a storage medium, characterized in that: When the processor reads the computer program stored in the storage medium, the computer executes the method of claim 1 .

10. A computer program product, being a computer program, characterized in that When the computer program is executed, the method of claim 1 is implemented.

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