On affine invariant descriptors related to SIFT

Sadek, Rida; Constantinopoulos, Constantinos; Meinhardt Llopis, Enric; Ballester, Coloma; Caselles, Vicente

doi:http://dx.doi.org/10.1137/100798739

On affine invariant descriptors related to SIFT

Citation

Sadek R, Constantinopoulos C, Meinhardt E, Ballester C, Caselles V. On affine invariant descriptors related to SIFT. SIAM J Imaging Sci. 2012 Jun 5;5(2):652-87. DOI: 10.1137/100798739

Abstract

Using a classical result on algebraic invariants of the unimodular group, we present in this paper some basic geometric affine invariant quantities, and we use them to construct some distinctive descriptors for object detection. Although full affine invariance cannot be guaranteed due to noncommutativity of camera blur with affine maps and the domain problem (that is, the difficulty of finding an affine covariant domain), the proposed descriptors behave more robustly than SIFT with respect to affine deformations. This is supported by our comparisons both with the version of SIFT computed on an affine normalized neighborhood, and with ASIFT, which solves both the previously mentioned camera blur and domain problems by cleverly sampling the orbit of affine transformations of the images.