Shadow Removal via Flash/Noflash Illumination

Lu, Cheng, Drew, Mark S. and Finlayson, Graham D. (2006) Shadow Removal via Flash/Noflash Illumination. In: IEEE Workshop on Multimedia Signal Processing, 2006-10-03 - 2006-10-06.

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Shadows bedevil multimedia applications, e.g. seeing into shadow regions in surveillance video. Model-based and non-model based, statistical methods, spatial, temporal, and invariant-based methods have been devised for combatting the shadow problem. Here we take a different approach, by attenuating the shadow by utilizing a second image under another illuminant to remove the effect of shadow-edges from an edge map of each frame. As a precursor step, we examine flash/noflash still image pairs. A flash image provides lessened shadows, but other shadows are produced. We can produce a flash-only (no ambient) image by subtracting the two images, but several artifacts remain. Instead, we have used the pure-flash image to detect the ambient shadows [ICME06]. However that method may fail when there are flash-shadows or specularities in the copy region. Here we manipulate the gradient field using a smoothing step including the directionality of edges near the shadow boundary, with improved results

Item Type: Conference or Workshop Item (Paper)
Faculty \ School: Faculty of Science > School of Computing Sciences
UEA Research Groups: Faculty of Science > Research Groups > Colour and Imaging Lab
Faculty of Science > Research Groups > Interactive Graphics and Audio
Depositing User: Vishal Gautam
Date Deposited: 07 Jun 2011 19:55
Last Modified: 21 Apr 2023 20:32
DOI: 10.1109/MMSP.2006.285296

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