Tire Defect Detection Using Consensus Interpolation
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Solution Overview
Problem
Existing methods for detecting defects in tires that alter the height profile are inefficient due to variations in tire size, deformability, and radial/lateral runout, leading to false defect detection and the need for an ideal reference model, which complicates precise and reliable in-line quality control in tire production.
Innovation Solution
The use of consensus interpolation, specifically the RANSAC algorithm, to calculate a reference height profile of tire surface portions, allowing for precise detection of defects without an ideal reference model, by filtering out variations and discarding points corresponding to defects, enabling fast and accurate defect detection in tire production lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If comparison with an ideal reference model is used for defect detection, then measurement precision is improved, but device complexity increases due to the need for an ideal reference model
Solution Approach 1:
The patent creates a digital copy of the tire surface through 3D scanning and generates a reference profile from multiple measured profiles. This digital copying approach eliminates the need for physical ideal reference models while maintaining measurement precision for defect detection
Solution Approach 2:
The patent transforms the physical tire surface into digital parameters (3D coordinates, height profiles) and uses statistical parameters (mean, standard deviation) to characterize surface variations. This parameter transformation enables precise defect detection without requiring an ideal physical reference model
2Reliability
If traditional defect detection methods are used, then reliability is improved by detecting defects, but productivity decreases due to false positives requiring manual verification
Solution Approach 1:
The patent performs preliminary processing of tire surface profiles by calculating mean and standard deviation to establish expected variation ranges before defect detection. This preliminary characterization reduces false positives by distinguishing normal variations from actual defects, maintaining reliability while improving productivity
Solution Approach 2:
The patent uses feedback from multiple measured profiles to continuously refine the reference profile and adjustment values. This feedback mechanism improves detection reliability by adapting to actual tire variations while reducing false alarms that would require manual verification
3Productivity
If in-line defect detection is implemented, then productivity is improved by continuous production, but measurement precision decreases due to time constraints and tire variations
Solution Approach 1:
The patent calculates adjustment values from multiple measured profiles before final defect detection. This preliminary action compensates for tire size variations and runout effects, maintaining measurement precision even under the time constraints of in-line production
Solution Approach 2:
The patent measures and processes multiple profiles (excessive action) beyond a single measurement to compensate for tire variations. This partial redundancy approach ensures measurement precision is maintained while keeping each individual measurement quick enough for in-line production
Data Source
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AI summary
A method is described for detecting defects on tyres in a tyre production process. The method comprises providing a tyre, comprises acquiring (202) a three-dimensional image of a surface portion of the tyre, comprises generating (204), as a function of the acquired image, a plurality of values indicating the measure of a height profile (S_pa) of the surface portion of the tyre, comprises calculating (205), as a function of the plurality of values of the measure of the height profile and according to a consensus interpolation, a plurality of values indicating an estimation of a reference height profile (<Spar>) of the surface portion of the tyre, comprises calculating (206), as a function of the plurality of values of the measure of the height profile and of the estimation of the reference height profile, a height profile of possible defects (S_papd) in the surface portion of the tyre, and comprises comparing (207, 208) values of the height profile of possible defects with respect to a threshold value (S_th) in order to detect possible defects in the surface portion of the tyre.