Directional Inspection Lighting for Shadow-Based Defect Imaging
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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, but the probability of detecting cracks and defects decreases and surface contours become difficult to discern
Solution Approach 1:
The patent applies local quality by transitioning from uniform diffuse lighting to localized directional lighting. Multiple light sources are positioned at specific locations around the inspection camera, each illuminating specific regions from angled directions. This creates locally varied illumination patterns that cast shadows on surface irregularities, enhancing the visibility of cracks and defects while maintaining overall illumination coverage.
Solution Approach 2:
The patent employs asymmetry by positioning light sources asymmetrically around the inspection camera rather than uniformly distributing them. The light sources are placed at offset positions at specific angles (e.g., 45 degrees) relative to the camera axis, creating asymmetric illumination patterns that produce directional shadows. This asymmetric arrangement enhances contrast for detecting surface defects by emphasizing their three-dimensional characteristics.
2Measurement precision
If directional light sources are offset from the inspection camera, then shadows are created that enhance contrast and visibility of defects, but the system complexity increases
Solution Approach 1:
The patent merges the lighting array with the inspection camera into a single integrated probe assembly. Multiple light sources are mounted on the housing surrounding the camera, combining illumination and imaging functions in one device. This integration reduces overall system complexity by eliminating separate lighting equipment and simplifies operation by coordinating light and camera activation through a single system.
Solution Approach 2:
The inspection system achieves multi-functionality by incorporating both illumination and imaging capabilities in a single probe. The lighting array serves multiple purposes: it provides overall illumination, creates directional shadows for defect detection, and can be activated selectively for different inspection modes. This universal design allows one device to perform multiple inspection functions without requiring separate specialized equipment.
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 significantly increases the visibility of structural features and defects by creating shadows, allowing for better detection and analysis of minute surface variations.
Implementation Method 1
a directional light source positioned in an offset position from a central axis of the inspection camera. The directional light source can be configured to emit light onto a surface of interest so as to produce shadows
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.