What characterizes a shadow boundary under the sun and sky?

  • Authors:
  • Xiang Huang; Gang Hua;Jack Tumblin;Lance Williams

  • Affiliations:
  • EECS Dept., Northwestern University, USA;Computer Science Dept., Stevens Institute of Technology, USA;EECS Dept., Northwestern University, USA;Multimedia Lab, Nokia Research Center, USA

  • Venue:
  • ICCV '11 Proceedings of the 2011 International Conference on Computer Vision
  • Year:
  • 2011

Quantified Score

Hi-index 0.00

Visualization

Abstract

Despite decades of study, robust shadow detection remains difficult, especially within a single color image. We describe a new approach to detect shadow boundaries in images of outdoor scenes lit only by the sun and sky. The method first extracts visual features of candidate edges that are motivated by physical models of illumination and occluders. We feed these features into a Support Vector Machine (SVM) that was trained to discriminate between most-likely shadow-edge candidates and less-likely ones. Finally, we connect edges to help reject non-shadow edge candidates, and to encourage closed, connected shadow boundaries. On benchmark shadow-edge data sets from Lalonde et al. and Zhu et al., our method showed substantial improvements when compared to other recent shadow-detection methods based on statistical learning.