Tire Image Rectification via Circumferential Marking
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Solution Overview
Problem
Visual inspection of tires during production is hindered by imperfections introduced during image acquisition, such as mechanical system errors and tire curvature, leading to distortion and confusion between intrinsic and induced deformations.
Innovation Solution
A method for image rectification involves detecting a circumferential marking on the tire, determining position references, calculating radial shifts for pixel alignment, and applying filters like the Sobel filter for contour detection and consistency checks to straighten the image before further processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If mechanical means are used to rotate the tire during image acquisition, then the entire tire surface can be inspected, but mechanical rotation errors and tire curvature cause image distortion and misalignment
Solution Approach 1:
The patent replaces mechanical correction methods with a digital image processing system. A marking detection device detects circumferential markings on the tire, and a processing unit calculates and applies radial shifts to pixel positions based on detected marking positions, substituting mechanical precision requirements with computational correction
Solution Approach 2:
The patent changes the parameter space by introducing radial shift values calculated from marking positions. The processing unit determines difference values between actual and ideal marking positions, then applies these as radial shift parameters to correct pixel positions, transforming geometric distortion through parameter transformation
2Adaptability or versatility
If the tire is rotated on a platform or through rollers, then images of different tire regions can be acquired, but the tire may become misaligned with the data acquisition system
Solution Approach 1:
The patent introduces circumferential markings on the tire as intermediary reference elements. These markings serve as mediators between the tire rotation system and the image acquisition system, providing detectable reference points that enable precise alignment measurement and correction without requiring perfect mechanical alignment
3Manufacturing precision
If costly mechanical improvements are made to the rotation system, then alignment may improve, but the expense increases and curvature imperfections from uninflated tire movement remain uncorrected
Solution Approach 1:
The patent replaces expensive mechanical improvements with an affordable digital image processing system. The marking detection device and processing unit provide a low-cost alternative to upgrading mechanical rotation systems, correcting alignment and curvature issues through computational methods rather than mechanical modifications
Data Source
Figure 1~2
AI summary
The invention relates to a method for rectifying an image representing a tire surface, including the following steps: detecting a circumferential marking (12) present on the tire on the image (1); determining a position reference on the tire on the basis of said marking (12) and for each line in the image; determining the difference between the reference position on the current line and the minimum value of the reference positions for each line in the image and for all the lines in the image; and radially offsetting the pixels of each line by the value of said difference.