6 December 2002 Phase-only filter solution based on fuzzy logic for the defocus problem
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One of the main problems in imaging systems is the difficulty in placing the output CCD exactly at the imaging plane. This causes the so-called defocus effect in which the optical transfer function in the output plane is worse than expected. This leads to loss of detail and possible contrast conversion. A good solution for solving the defocus problem in a specific plane would be to place a phase-only filter right after (or before) the lens of the imaging setup. This filter can be designed to cancel the defocusing effect in the specific plane. The design of a filter that will yield good images for a range of planes at different distances from the actual imaging plane requires a more complex approach. In this work the authors introduce a novel method for designing the filter using Fuzzy Logic principles. The Fuzzy Logic inference engine accepts as input data a set of filters; each designed for good results in a specific region, and collaborates them to produce a single phase-only filter. The optical transfer function of the combined filter in the various regions is presented to demonstrate the improvement in limiting defocus.
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Eran Gur, Eran Gur, Zeev Zalevsky, Zeev Zalevsky, Dina Elkind, Dina Elkind, David Mendlovic, David Mendlovic, } "Phase-only filter solution based on fuzzy logic for the defocus problem", Proc. SPIE 4787, Applications and Science of Neural Networks, Fuzzy Systems, and Evolutionary Computation V, (6 December 2002); doi: 10.1117/12.453538; https://doi.org/10.1117/12.453538


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