Contrast Image Generation Using Angular Illumination Sequences
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Solution Overview
Problem
Existing contrast imaging methods, such as DIC and DPC, generate directionally dependent grey level images, ignoring or lessening other properties of the object structure, particularly in representing height and phase profile information.
Innovation Solution
A method involving angularly selective lighting using multiple illumination sources to create colour gradient images, which are then transformed into a colour space to represent directional information of the object's height or phase profile in a colour-coded manner, allowing for the combination of multiple contrasts into a single image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DIC or DPC methods are used to generate contrast images, then directional information of height or phase profile is emphasized, but other properties of the object structure are ignored or lessened
Solution Approach 1:
The patent combines multiple illumination images taken from different angular directions and merges them into a single composite image. This merging process preserves both the directional height/phase information (through differential processing of adjacent angular images) and other object properties (through integration of information from multiple viewing angles), thereby resolving the contradiction between emphasizing directional information and retaining comprehensive object information.
Solution Approach 2:
The patent transitions from conventional 2D grey-scale contrast imaging to 3D color-coded imaging by adding the angular dimension as a third dimension. Each pixel in the final image contains color information encoding the angular direction of illumination, thereby preserving directional information without sacrificing other object properties. This dimensional expansion allows simultaneous representation of multiple object characteristics.
2Ease of manufacture
If conventional contrast methods are used, then image acquisition is simple, but the ability to represent three-dimensional height and phase profile information is limited
Solution Approach 1:
The patent employs periodic action by systematically varying the illumination angle through a sequence of discrete angular positions. Multiple images are acquired at different angles in a periodic sequence, and through computational processing, this periodic angular variation is transformed into three-dimensional height and phase profile information. This approach maintains relative simplicity in image acquisition while achieving precise 3D measurement capabilities.
3Loss of information
If multiple illumination images are acquired and processed to create color-coded directional information, then comprehensive object information is obtained, but processing complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the illumination angle parameter across multiple images and then transforming these angular parameter variations into color-coded directional information in the final composite image. The processing complexity is managed by focusing the parameter transformation on a single key attribute (illumination angle) rather than attempting to process all possible image features, thereby obtaining comprehensive object information with controlled processing complexity.
Data Source
AI summary
The invention relates to a contrast formation method, for generating a contrast image, including the steps: Illuminating an object by an illumination sequence based on one or more illumination sources; creating an illumination image of the object for each illumination in the illumination sequence; overlaying two respective illumination images which neighbor each other with respect to a first axis to form a first total axis image of the first axis; overlaying two respective illumination images which neighbor each other with respect to a second axis to form a second total axis image of the second axis; creating a first color gradient image based on the first total axis image; creating a second color gradient image based on the second total axis image; transforming the first color gradient image and the second color gradient image into a color space; and generating a contrast image, based on the transformed first color gradient image and the second color gradient image into the color space.