Tire Surface Defect Inspection with Shadow-Based 3D Reconstruction
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Solution Overview
Problem
Existing machine-assisted tire testing methods have unsatisfactory defect detection rates for surface damage due to two-dimensional image analysis, missing many minor defects.
Innovation Solution
Utilizing multiple two-dimensional image recordings under different lighting conditions to derive three-dimensional profile information of the tire surface, employing shadow-based reconstruction and photometric stereo analysis to enhance defect detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two-dimensional image analysis is used for tire surface inspection, then the device complexity is low, but the defect detection rate is unsatisfactory
Solution Approach 1:
The patent transforms two-dimensional image data into three-dimensional surface profile information by analyzing shadow patterns from multiple illumination angles. This dimensional transformation enables detection of surface defects that are invisible in 2D images, directly resolving the contradiction between simple device operation and high defect detection rate
Solution Approach 2:
The system changes the illumination angle parameter to generate different shadow patterns on the tire surface. By varying the light incidence angle and analyzing the resulting shadow configurations, the system extracts three-dimensional surface information, achieving high defect detection without requiring complex direct 3D sensing hardware
2Measurement precision
If multiple illumination states are used to improve defect detection, then the measurement precision increases, but the productivity decreases due to multiple image recordings
Solution Approach 1:
The system uses periodic rotation of the tire combined with multiple illumination states to capture images at different positions and lighting conditions. This periodic action allows comprehensive surface inspection while maintaining continuous motion, preventing productivity loss despite multiple recordings
Solution Approach 2:
The system performs preliminary shadow-based reconstruction to generate three-dimensional surface profiles from the captured images. This preliminary processing of surface geometry information enables efficient defect detection in subsequent steps, maintaining high inspection speed while achieving precise defect detection
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
Significantly increases the detection precision and rate of surface defects and damage, allowing for reliable and fast identification of even minor issues.
Implementation Method 1
lighting with an oblique light incidence angle relative to the tire surface to be inspected enables image-based detection of defective, faulty, or damaged surface areas
Implementation Method 2
generating a plurality of two-dimensional images of the illuminated surface area by means of at least one image recording device
Data Source
Figure 1~3
AI summary
The invention relates to a method for testing tires (100), comprising the steps of: illuminating a surface area (104) of a tire (100) to be tested by means of an illumination device (12), generating several two-dimensional images of the illuminated surface area (104) by means of at least one image acquisition device (26) and evaluating the several two-dimensional image acquisitions by means of an evaluation device to detect defects, faults and/or damage on the surface (102) of the tire (100).