Determination of blur and affine combined invariants by normalization

The determination of invariant characteristics is an important problem in pattern recognition. In many situations, images to be processed are usually subjected to geometric distortion and/or blur degradation. In this paper, we introduce an approach to derive blur and affine combined invariants (BAI). Firstly we normalize the image to a standard form by using blur invariant moments as normalization constraints. Then, we construct the blur and affine combined invariants at the standard form. Using the method proposed in this paper, a set of blur and affine combined invariant features can be obtained easily and effectively. Several experimental results are presented to illustrate the performance of the invariants for simultaneously affine deformed and blur degraded images. (C) 2001 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved.