Partially occluded faces are common in many applications
of face recognition. While algorithms based on sparse
representation have demonstrated promising results, they
achieve their best performance on occlusions that are not
spatially correlated (i.e. random pixel corruption). We show
that such sparsity-based algorithms can be significantly improved
by harnessing prior knowledge about the pixel error
distribution. We show how a Markov Random Field model
for spatial continuity of the occlusion can be integrated into
the computation of a sparse representation of the test image
with respect to the training images. Our algorithm efficiently
and reliably identifies the corrupted regions and
excludes them from the sparse representation. Extensive experiments
on both laboratory and real-world datasets show
that our algorithm tolerates much larger fractions and varieties
of occlusion than current state-of-the-art algorithms.