Separation and contrast enhancement of overlapping cast shadow components using polarization

Shih Schön Lin, Konstantin M. Yemelyanov, Edward N Pugh Jr, Nader Engheta

Research output: Contribution to journalArticlepeer-review

58 Scopus citations


Shadow is an inseparable aspect of all natural scenes. When there are multiple light sources or multiple reflections several different shadows may overlap at the same location and create complicated patterns. Shadows are a potentially good source of information about a scene if the shadow regions can be properly identified and segmented. However, shadow region identification and segmentation is a difficult task and improperly identified shadows often interfere with machine vision tasks like object recognition and tracking. We propose here a new shadow separation and contrast enhancement method based on the polarization of light. Polarization information of the scene captured by our polarization-sensitive camera is shown to separate shadows from different light sources effectively. Such shadow separation is almost impossible to realize with conventional, polarization-insensitive imaging.

Original languageEnglish (US)
Pages (from-to)7099-7108
Number of pages10
JournalOptics Express
Issue number16
StatePublished - 2006
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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