Wire Rope Diameter Measurement Using Stereo Triangulation
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Solution Overview
Problem
Existing methods for measuring rope diameters, such as those using area cameras or projectors, face limitations in resolution, are costly, and fail to account for vibrations that cause fluctuations in camera distance, making accurate measurements impossible.
Innovation Solution
A wired-rope measuring device employing two line-sensor cameras that apply the principle of triangulation to analyze image data and correct for volumetric anamorphosis, allowing for precise diameter calculation without the need for conversion coefficients or additional projectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an area camera is used to measure rope diameter, then the device complexity is reduced, but the measurement precision deteriorates
Solution Approach 1:
The patent divides the measurement task into multiple viewing angles by using two cameras positioned at different locations. Each camera captures the rope from a specific angle, and the measurement system processes these segmented views separately before combining results. This segmentation allows each camera to focus on a specific measurement aspect, improving overall precision while maintaining manageable device complexity.
Solution Approach 2:
The patent transitions from single-angle measurement to multi-angle measurement by adding spatial dimension. Instead of relying on one camera's limited perspective, the system captures rope images from multiple dimensions (different angles and positions), enabling more accurate diameter calculation through stereo vision and eliminating the trade-off between simplicity and precision.
2Measurement precision
If a projector is used for each rope to measure diameter, then the measurement precision is improved, but the device complexity and cost increase significantly
Solution Approach 1:
The patent merges the functions of multiple projectors into a single camera-based measurement system. Instead of requiring separate projector devices for each rope, the system combines multiple camera views to achieve the same measurement capability, significantly reducing device complexity while maintaining precision through image processing and geometric calculation.
Solution Approach 2:
The patent replaces the mechanical projector system with an optical camera system. Instead of using projectors to physically mark or measure the rope, the system uses cameras to capture optical images and processes these images computationally to determine diameter, eliminating the need for complex mechanical measurement devices.
3Ease of operation
If conversion coefficients are calculated in advance for image processing, then the ease of operation is improved, but the reliability deteriorates when rope vibration changes camera distance
Solution Approach 1:
The patent implements a dynamic measurement approach where the system continuously adapts to changing conditions. Instead of using fixed conversion coefficients, the system calculates measurement parameters in real-time based on current camera positions and rope locations. This dynamic calculation ensures reliability under vibration while maintaining ease of operation through automated processing.
Solution Approach 2:
The patent incorporates feedback mechanisms where the measurement system continuously monitors camera-to-rope distance and adjusts conversion coefficients accordingly. The system uses real-time distance information from the dual-camera setup to update calculation parameters, ensuring accurate measurements even when vibration causes distance fluctuations, while maintaining operational simplicity through automated feedback loops.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise, cost-effective measurement of rope diameters even under vibrating conditions, eliminating the need for recalculating conversion coefficients and using multiple projectors, with improved resolution and stability.
Implementation Method 1
the analyzing device applies the principle of triangulation by a stereo method to the image data to seek coordinates of the wired rope relative to the cameras
Implementation Method 2
volumetric anamorphosis is corrected when calculating a diameter of the wired rope based on the coordinates of the wired rope
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A wired-rope measuring device, provided with two cameras 1, 2 that shoot one or no less than two wired ropes 8 from different directions and an analyzing device 5 that analyzes image data that is an image shot by the two cameras 1, 2, wherein the analyzing device 5 applies the principle of triangulation by a stereo method to the image data to seek a center coordinate P0 of the wired rope 8 relative to the cameras 1, 2 and volumetric anamorphosis is corrected when calculating a diameter D of the wired rope 8 based on the center coordinate P0 of the wired rope 8.