Hemispherical Lighting Array for Surface Defect Detection
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Solution Overview
Problem
Current surface defect detection methods are prone to human error due to subjective interpretation and lack of standardization, leading to inconsistent results and lengthy analysis processes.
Innovation Solution
A device comprising an optical device, a lighting system with multiple light sources arranged in a half-sphere, and an electronic calculation unit that acquires images of the surface from different lighting directions, calculates parameters to characterize surface responses, and objectively determines defect presence using predefined criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple operators view the surface image to improve detection reliability, then the reliability of defect detection is improved, but the time required for analysis increases significantly
Solution Approach 1:
The system performs self-inspection through automated image acquisition from multiple angles and algorithmic analysis, eliminating the need for multiple human operators while maintaining high detection reliability. The device autonomously processes surface images and generates defect detection results without requiring human time investment for manual review.
Solution Approach 2:
The patent replaces the mechanical process of multiple human operators visually inspecting surfaces with an automated optical imaging system combined with computational algorithms. The system uses multiple cameras or a single camera with multi-angle lighting to capture surface images, then applies image processing algorithms to objectively detect defects, substituting human visual inspection with automated optical-mechanical-electronic systems.
2Measurement precision
If surface images are viewed by multiple operators with examples to improve measurement precision, then the accuracy of defect identification is improved, but the complexity of the inspection process increases
Solution Approach 1:
The system transforms the inspection process from subjective visual assessment to objective quantitative analysis by capturing images from multiple predetermined angles and using algorithms to analyze specific parameters such as reflectance patterns, shadow lengths, and surface topology. This converts qualitative defect identification into measurable parameter-based detection, improving precision while standardizing the process.
Solution Approach 2:
The inspection process is segmented into distinct automated steps: image acquisition from multiple angles, preprocessing of images, feature extraction, defect detection algorithms, and result generation. This segmentation allows each step to be optimized independently and executed automatically, reducing overall process complexity while maintaining high accuracy through systematic analysis.
3Device complexity
If conventional lighting is used for surface inspection, then the device complexity is reduced, but the ability to detect defects from different angles is limited
Solution Approach 1:
The patent employs a hemispherical or curved lighting array surrounding the inspection area, with light sources distributed along a circular or hemispherical path. This curved geometry allows illumination from all azimuthal angles around the surface, enabling detection of defects with various orientations and reflectance properties. The spherical arrangement ensures that for any surface point, light arrives from multiple directions, creating detectable shadows and highlights that reveal defect geometry.
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
The solution enables efficient, objective, and standardized detection of surface defects, reducing human error and analysis time while providing a portable and easily deployable tool for inspecting surfaces.
Implementation Method 1
the light which successively strikes the surface at different angles of incidence and which is reflected on said surface is measured by an image sensor
Data Source
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AI summary
The invention relates to a device for detecting a defect on a surface, comprising: - an optical device (14) suitable for acquiring an image of the surface in a given optical direction, - a lighting device (15) comprising a plurality of light sources (16), the light sources (16) being arranged in a hemisphere (20), each light source (16) having an off and an on state, - an electronic calculation device (18). The electronic calculation device (18) is able to control the optical device (14) and the lighting device (15) so that the optical device (14) acquires a plurality of images of the surface, different light sources (16) or different combinations of light sources (16) being switched on for each image, the hemisphere (20) having a diameter D smaller than or equal to 50 mm.