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Detecting And Segmenting Un-Occluded Items By Actively Casting Shadows, Tze K Koh, Amit Agrawal, Ramesh Raskar, Steve Morgan, Nicholas Miles, Barrie Hayes-Gill
Detecting And Segmenting Un-Occluded Items By Actively Casting Shadows, Tze K Koh, Amit Agrawal, Ramesh Raskar, Steve Morgan, Nicholas Miles, Barrie Hayes-Gill
Research Collection College of Integrative Studies
We present a simple and practical approach for segmenting un-occluded items in a scene by actively casting shadows. By ‘items’, we refer to objects (or part of objects) enclosed by depth edges. Our approach utilizes the fact that under varying illumination, un-occluded items will cast shadows on occluded items or background, but will not be shadowed themselves.We employ an active illumination approach by taking multiple images under different illumination directions, with illumination source close to the camera. Our approach ignores the texture edges in the scene and uses only the shadow and silhouette information to determine the occlusions. We show …
Segmentation Of Overlapping Particles In Automatic Size Analysis Using Multi-Flash Imaging, Tze K Koh, Nicholas Miles, Steve Morgan, Barrie Hayes-Gill
Segmentation Of Overlapping Particles In Automatic Size Analysis Using Multi-Flash Imaging, Tze K Koh, Nicholas Miles, Steve Morgan, Barrie Hayes-Gill
Research Collection College of Integrative Studies
In this paper, we propose a novel hardware approach to image segmentation, specifically in the case of overlapping particles. Our research is based on multi-flash imaging (MFI), originally developed to detect depth discontinuities. Multiple images captured with different illumination conditions provide additional information about a scene compared to conventional segmentation techniques. Shadows are used to identify true object edges and underlying particles. We applied the new approach in automated particle size analysis and evaluated it against the watershed and canny edge detection techniques. Evaluation results confirm that MFI can be applied in image segmentation and reveals the superiority of the …