Directional Lighting Inspection for Surface Defect Visibility
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Solution Overview
Problem
Current inspection systems for devices like jet engines face challenges in detecting wear and tear due to uniform diffuse lighting, which reduces the probability of identifying cracks and other defects, and makes it difficult to discern surface contours.
Innovation Solution
Employing directional light sources offset from the inspection camera's field of view to create varying illumination, casting shadows that enhance contrast and highlight defects, combined with a post-processing system to analyze these images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If uniform diffuse lighting is used to illuminate the interior surface, then the illumination is even and uniform across the surface, but the probability of detecting cracks and defects is reduced and surface contours are difficult to discern
Solution Approach 1:
The patent applies local quality by transitioning from uniform diffuse lighting to directional lighting that creates localized variations in illumination. The directional light sources are positioned to illuminate specific areas at different angles, creating localized shadows and highlights that reveal surface contours and defects while maintaining overall illumination coverage.
Solution Approach 2:
The patent employs asymmetry by positioning multiple directional light sources at different angular positions relative to the inspection camera rather than using symmetric uniform lighting. This asymmetric arrangement creates varying shadow patterns and contrast levels across the illuminated surface, enhancing the visibility of surface features and defects.
2Measurement precision
If directional light sources are positioned in an offset position from the inspection camera, then shadows are produced that enhance contrast and visibility of defects, but the system complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the illumination function into multiple independent directional light sources positioned at different angular locations. Each light source independently contributes to illuminating the surface from a specific direction, and their combined effect creates comprehensive defect detection capability while maintaining modular system architecture.
Solution Approach 2:
The patent implements multi-functionality by designing the lighting array to perform multiple functions: illumination, shadow creation, and surface contour enhancement. The same directional light sources that provide illumination also create the shadow patterns necessary for defect detection, eliminating the need for separate lighting and imaging subsystems.
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 use of directional lighting and post-processing significantly improves the visibility of minute surface variations and defects by increasing contrast, enabling more accurate defect detection.
Implementation Method 1
employing directional light sources offset from the inspection camera's field of view to create varying illumination, casting shadows that enhance contrast and highlight defects
Data Source
AI summary
An inspection system and related methods that employ directional light for enhanced imaging are provided. The inspection system includes an inspection camera and at least one directional light source positionable in an offset position from a field of view of the inspection camera. The at least one directional light source is configured to emit directional light from the offset position into the field of view of the inspection camera so as to produce shadows on a surface of interest. Further, the inspection system includes a display device coupled to the inspection camera and the inspection camera is configured to capture one or more images of the shadows produced on the surface of interest. The display device is configured to receive and display the one or more images.