Shadow Removal via Flash/Noflash Illumination

C. Lu, M. S. Drew, G. D. Finlayson

Research output: Contribution to conferencePaper

5 Citations (Scopus)

Abstract

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
Original languageEnglish
Pages198-201
Number of pages4
DOIs
Publication statusPublished - Oct 2006
EventMMSP'06: IEEE Workshop on Multimedia Signal Processing - Victoria, BC
Duration: 3 Oct 20066 Oct 2006

Conference

ConferenceMMSP'06: IEEE Workshop on Multimedia Signal Processing
CityVictoria, BC
Period3/10/066/10/06

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