Tyre Surface Inspection Using Stokes Vector Polarisation Analysis
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Solution Overview
Problem
Existing methods for optical inspection of tyres in production lines are time-consuming and lack accuracy in detecting surface irregularities and foreign bodies, leading to prolonged production times and potential defects.
Innovation Solution
A method and apparatus utilizing the Stokes vector components Q, U, and V to analyze the optical intensity of light reflected from a tyre's surface, reducing the number of acquisitions needed for inspection, allowing for faster and more accurate detection of surface flaws using non-polarized incident light and a detection system with polarisers and cameras.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple acquisitions of reflected light on different polarisation states are performed, then detection accuracy of surface irregularities is improved, but production time is increased
Solution Approach 1:
The patent applies partial action by performing only 1-3 acquisitions instead of the conventional minimum of 3 acquisitions for each polarisation state. This reduction in the number of acquisitions decreases inspection time while maintaining adequate detection accuracy through the use of Stokes vector analysis
Solution Approach 2:
The patent changes the parameter of acquisition number from the conventional minimum of 3 to a reduced value of 1-3 acquisitions total. This parameter change, combined with Stokes vector analysis, allows maintaining detection accuracy while reducing production time
2Reliability
If conventional optical inspection methods are used, then surface irregularities can be detected, but the inspection process is time-consuming
Solution Approach 1:
The patent substitutes the conventional mechanical approach of multiple sequential acquisitions with an optical analysis method based on Stokes vector components. This substitution enables faster inspection by analyzing light polarization properties directly rather than performing multiple time-consuming acquisitions
Solution Approach 2:
The patent changes the inspection parameter from multiple acquisitions to Stokes vector analysis, transforming the inspection process from a time-intensive sequential measurement to a faster optical property analysis that maintains detection reliability
3Productivity
If Stokes vector analysis with reduced acquisitions is implemented, then production time is reduced, but detection accuracy may be compromised
Solution Approach 1:
The patent changes the parameter of acquisition number to 1-3 while introducing Stokes vector analysis as a compensating method. This parameter change maintains detection accuracy by analyzing the polarization state of reflected light, which provides sufficient information about surface irregularities even with fewer acquisitions
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 efficient and precise quality control of tyres in production lines, reducing production time while improving detection accuracy of surface irregularities and foreign bodies without significantly impacting productivity.
Implementation Method 1
detecting the optical intensity of the light radiation reflected by said surface portion on a number N of pairs of polarisation states belonging to a group of three pairs of polarisation states corresponding to three pairs of points on Poincaré sphere
Implementation Method 2
detect the optical intensity of the light radiation reflected by said surface portion
Data Source
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AI summary
Method, and relative apparatus, for controlling tyres or semi-finished products in a tyre production line (1 ), comprising: - lighting with a light radiation the surface of a tyre or semi-finished product (101); - detecting the optical intensity of the light radiation reflected by the surface on a number N, with N ranging from 1 to 3, of pairs of polarisation states belonging to a group of three pairs of polarisation states situated at the opposite ends of three respective diameters of the Poincaré sphere orthogonal to each other; - calculating a number M, with M ranging from 1 to 3, of values representative of an equivalent number of components of the Stokes vector belonging to a subgroup of three components of the Stokes vector comprising a second component, Q, equal to the difference of the two optical intensities of the light radiation reflected by the surface on the first pair of polarisation states, a third component, U, equal to the difference of the two optical intensities of the light radiation reflected by the surface on the second pair of polarisation states and a fourth component, V, equal to the difference of the two optical intensities of the light radiation reflected by the surface on the third pair of polarisation states; - generating a respective control signal representative of each Stokes component; - analysing the respective control signal for detecting the possible presence of flaws on the surface.