A sparse texture representation using local affine regions

This article introduces a texture representation suitable for recognizing images of textured surfaces under a wide range of transformations, including viewpoint changes and non-rigid deformations. At the feature extraction stage, a sparse set of a#ne Harris and Laplacian regions is found in the image. Characteristic ellipses associated with these regions are mapped onto circles to achieve a#ne invariance, and the appearance of the corresponding normalized patches is represented using two novel ...