Rank Constrained Recognition under Unknown Illuminations

  • Authors:
  • Shaohua Zhou;Rama Chellappa

  • Affiliations:
  • -;-

  • Venue:
  • AMFG '03 Proceedings of the IEEE International Workshop on Analysis and Modeling of Faces and Gestures
  • Year:
  • 2003

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Abstract

Recognition under illumination variations is a challenging problem.The key is to successfully separate the illumination source fromthe observed appearance. Once separated, what remains is invariantto illuminant and appropriate for recognition. Most current effortsemploy a Lambertian reflectance model with varying albedo fieldignoring both attached and cast shadows, but restrict themselves byusing object-specific samples, which undesirably deprives them ofrecognizing new objects not in the training samples. Using rankconstraints on the albedo and the surface normal, we accomplishillumination separation in a moregeneral setting, e.g., withclass-specific samples via a factorization approach. In addition,we handle shadows (both attached and cast ones) by treating them asmissing values, and resolve the ambiguities in the factorizationmethod by enforcing integrability. As far as recognition isconcerned, a bootstrap set which is just a collection of 2D imageobservations can be utilized to avoid the explicit requirement that3D information be available. Our approaches produce goodrecognition results as shown in our experiments usingthe PIEdatabase.