  This report concerns the use of techniques for sparse signal representation
and sparse error correction for automatic face recognition. Much of the recent
interest in these techniques comes from the paper "Robust Face Recognition via
Sparse Representation" by Wright et al. (2009), which showed how, under certain
technical conditions, one could cast the face recognition problem as one of
seeking a sparse representation of a given input face image in terms of a
"dictionary" of training images and images of individual pixels. In this
report, we have attempted to clarify some frequently encountered questions
about this work and particularly, on the validity of using sparse
representation techniques for face recognition.
