DESIGN OF STABLE IIR FILTERS ON A NON-UNIFORM SAMPLING SYSTEM FOR DEFOCUSING CORRECTION
V.A. Fursov
Image Processing Systems Institute, Russian Academy of Sciences, Federal State Research Center "Crystallography and Photonics", Russian Academy of Sciences, Samara, Russia
Keywords: digital processing of images, defocusing, IIR filter, stability
Abstract
The technology of constructing a recursive filter on a non-uniform grid of samples with parameter identification on test images is discussed. This filter is the IIR-filter that has a physical feasibility problem. To overcome it, a multi-step procedure is implemented. Unfortunately, identifying the best filter in terms of a given criterion does not guarantee that a recursive implementation of that filter will be stable. In the paper, for the considered iterative scheme, stability conditions are obtained. It has been experimentally confirmed that if, these conditions are met, it is possible to achieve a high quality of the correction. Based on the obtained criteria, a technology for correcting defocusing with control over the stability of estimates is proposed. The results of image correction showing the effectiveness of the technology are presented.
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