UC Berkeley; UC Berkeley
Poster: Heavy-tailed Distances for Gradient Based Image Descriptors
5:45 - 11:59pm Wednesday, December 14, 2011
This is part of the Poster Session which begins at 17:45 on Wednesday December 14, 2011
W017
http://books.nips.cc/nips24.html#P0302
Many applications in computer vision measure the similarity between images or image patches based on some statistics such as oriented gradients. These are often modeled implicitly or explicitly with a Gaussian noise assumption, leading to the use of the Euclidean distance when comparing image descriptors. In this paper, we show that the statistics of gradient based image descriptors often follow a heavy-tailed distribution, which undermines any principled motivation for the use of Euclidean distances. We advocate for the use of a distance measure based on the likelihood ratio test with appropriate probabilistic models that fit the empirical data distribution. We instantiate this similarity measure with the Gamma-compound-Laplace distribution, and show significant improvement over existing distance measures in the application of SIFT feature matching, at relatively low computational cost.