Exploring Patch Similarity In An Image

This article describes an experimental procedure to analyze (and verify) the self-similarity concept in natural images and to explore the Gaussianity of groups of similar patches extracted from a single image. The self-similarity assumption means that most image patches of a sufficient size are repeated, of course not identically, but with small variations. The procedure proposed in this paper, and implemented in the accompanying online demo, permits to explore and visualize these clusters of similar patches in a given image. Thanks to it, a user can select a patch in an image, group all patches similar to it up to a translation, or to an isometry, apply PCA to the group, make visual tests about the Gaussianity of the set of patches, and finally apply EM to the set to see if it is a mixture of Gaussians.