doi:10.1016/S0031-3203(03)00187-0
Copyright © 2003 Pattern Recognition Society. Published by Elsevier Science B.V.
Combined blur and affine moment invariants and their use in pattern recognition
Institute of Information Theory and Automation, Academy of Sciences of the Czech Republic, Pod vodárenskou v

í 4, 182 08, Prague 8, Czech Republic
Received 29 August 2002;
accepted 7 May 2003. ;
Available online 8 August 2003.
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Abstract
The paper is devoted to the recognition of objects and patterns deformed by imaging geometry as well as by unknown blurring. We introduce a new class of features invariant simultaneously to blurring with a centrosymmetric PSF and to affine transformation. As we prove in the paper, they can be constructed by combining affine moment invariants and blur invariants derived earlier. Combined invariants allow to recognize objects in the degraded scene without any restoration.
Author Keywords: Degraded image; Blur invariants; Affine moment invariants; Combined invariants; Object recognition
Fig. 1. The Lena subimage used in the first experiment: (a) original, (b) maximum skew, (c) maximum blurring, and (d) maximum skew and blurring.
Fig. 2. The relative error of
I1 and
I2 of the skewed and blurred images.
Fig. 3. The relative error of
I1 and
I2 of the blurred and noisy images.
Fig. 4. The comb. The viewing angle increases from 0° (top row) to 75° (bottom row). The extent of out-of-focus blur increases from left to right.
Fig. 5. (a) Original digits and (b–e) examples of the deformed digits used in the experiment.
Fig. 6. The digits 1, 2, 4, and 5 in the feature space of the combined invariants
I2 and
I6.
Fig. 7. The digits 1, 2, 4, and 5 in the feature space of the affine moment invariants
I2 and
I6.
Table 1. The values of the combined invariants of the comb

Table 2. The success rates of the affine moment invariants (AMI) and the combined affine and blur invariants (CBAI) in digit recognition
