Adaptive Diffuse Illumination for Curved Feature Inspection
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Solution Overview
Problem
Conventional brightfield illumination systems struggle with uniformly illuminating curved features of a unit under test (UUT), leading to hotspots and severe luminescence gradients, which complicates defect detection and requires extensive downstream image processing, especially when the surface finish is more specular than diffuse.
Innovation Solution
The adaptive diffuse illumination system uses a light source and a diffuser component to create uniform diffuse illumination by dispersing specular light, minimizing hotspots and saturation, and allowing for on-axis imaging with reduced ghosting and keystone distortions, enabling efficient defect detection without extensive image processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional brightfield illumination is used to illuminate curved features, then the illumination intensity is high enough to capture images, but hotspots and saturated areas are created where illumination and part geometry interact
Solution Approach 1:
The illumination system is segmented into multiple independent LED light sources arranged in an array, allowing each source to be controlled individually. This segmentation enables precise spatial distribution of light to eliminate hotspots while maintaining overall illumination intensity on curved features.
Solution Approach 2:
The system applies local quality control by independently adjusting the intensity of each LED source based on its position relative to the curved feature. This allows tailored illumination at each location to prevent saturation in high-reflectivity areas while ensuring adequate lighting in low-reflectivity areas.
2Ease of operation
If brightfield illumination is used with specular surface finishes, then images can be captured, but severe luminescence gradients are produced that complicate defect detection
Solution Approach 1:
The system dynamically adjusts the illumination profile by independently controlling each LED source in real-time. This dynamic control allows the system to adapt to varying surface geometries and specularities, producing uniform illumination that eliminates severe luminescence gradients and facilitates defect detection.
Solution Approach 2:
The system incorporates feedback mechanisms where the illumination pattern is adjusted based on detected surface characteristics. This feedback loop enables the system to compensate for specular reflections and geometric variations, producing consistent illumination that simplifies defect detection and measurement.
3Device complexity
If traditional brightfield techniques are used, then simple illumination setup is required, but extensive downstream image processing is needed to correct hotspots and gradients
Solution Approach 1:
The system performs preliminary action by pre-calculating and pre-adjusting the illumination pattern before image capture. The LED array is configured to produce the desired uniform illumination profile in advance, eliminating the need for extensive post-capture image processing to correct hotspots and gradients.
Solution Approach 2:
The system converts the potentially harmful effect of specular reflections into a benefit by using the reflection characteristics to guide the illumination adjustment. The controlled specular reflections from the curved features are used to inform the illumination pattern, transforming what would be a source of hotspots into a mechanism for achieving uniform illumination.
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 results in more uniform illumination profiles below camera saturation levels, reducing the need for downstream processing and decreasing inspection time, while also enabling the analysis of features that cannot be illuminated by traditional brightfield techniques.
Implementation Method 1
The adaptive diffuse illumination system uses a light source and a diffuser component to create uniform diffuse illumination by dispersing specular light
Data Source
AI summary
Systems and methods for illuminating and/or inspecting one or more features of a unit under test (UUT) are disclosed herein. A system configured in accordance with embodiments of the present technology can include, for example, a machine, one or more diffuser elements, and/or one or more light sources. The system can create and adjust brightfield illumination profiles (e.g., uniform, brightfield illumination profiles) on portions (e.g., on curved features) of the UUT by, for example, using the one or more light sources and/or the one or more diffuser elements to adjust diffuse and/or specular illumination projected onto the curved features of the UUT. In some embodiments, the system includes one or more darkfield light sources configured to project illumination onto second portions of the UUT to create a darkfield illumination profile. The system can capture data of the brightfield and/or darkfield illumination profiles and can thereby inspect portions of the UUT.