Surface Inspection of Long Products Using Multi-Angle Lighting
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Solution Overview
Problem
Current surface inspection systems for long products lack sensitivity and flexibility in detecting both small and wide-angle discontinuities, particularly in high-temperature environments, and are not adequately effective for materials with varying geometries and surface finishes.
Innovation Solution
The method employs multiple lighting groups and cameras positioned strategically around the product to capture images under various lighting conditions, using color cameras and different wavelengths to reconstruct the surface shape and detect defects, with two modalities for point and long defects, allowing for improved sensitivity and adaptability to different materials and finishes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a plurality of illuminators and image detectors are disposed around the long product with inclined angles, then the ability to detect surface defects is improved, but the device complexity increases
Solution Approach 1:
The illumination system is divided into multiple illuminators positioned at different locations around the long product, each projecting light at specific angles. The detection system is similarly segmented into multiple image detectors. This segmentation allows comprehensive surface coverage and defect detection from multiple perspectives without requiring a single complex system, thereby improving measurement precision while managing device complexity through modular arrangement.
2Measurement precision
If images are captured under various lighting conditions and processed to reconstruct surface shape, then the detection sensitivity for both small and wide angles is improved, but the processing time and computational complexity increase
Solution Approach 1:
The system captures multiple images under different lighting conditions simultaneously or in rapid succession before defect analysis begins. By preparing the complete set of images under various lighting angles in advance, the subsequent processing stage can focus solely on reconstructing surface shape and detecting defects without time-consuming data acquisition, thus improving detection sensitivity while minimizing additional processing time.
3Adaptability or versatility
If multiple illuminators project light at different angles, then the flexibility to detect various types of discontinuities is improved, but the device complexity and number of components increase
Solution Approach 1:
The illuminators and image detectors are designed with universal positioning and adjustment capabilities, allowing the same hardware configuration to detect multiple types of surface discontinuities including small defects, wide-angle defects, and various geometric irregularities. This multi-functionality approach enables a single system to perform diverse inspection tasks without requiring specialized components for each defect type, thereby improving adaptability while controlling device complexity.
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
This approach enhances the detection sensitivity and flexibility of surface defects, enabling effective inspection of long products at high temperatures and varying geometries, with reduced complexity and time, while minimizing background radiation interference.
Implementation Method 1
a plurality of illuminators disposed around the long product, each one projecting light with a set angle with respect to line perpendicular to lightened surface
Implementation Method 2
a plurality of image detectors, disposed around the long product, having main axis inclined with respect to said line with a second set angle
Data Source
Figure 1~2
Figure 3a~3c
Figure 4a~4c
AI summary
Method and apparatus for the surface inspection and detection of defects of long products by means of a combination of images of the same region of the long product, said images being taken under different lighting conditions, in order to reconstruct the shape of the surface and thus obtain information on the presence of defects.