Suppression of impulse noise in medical images with the use of fuzzy adaptive median filter

SUPPRESSION OF IMPULSE NOISE IN MEDICAL IMAGES WITH THE USEOF FUZZY ADAPTIVE MEDIAN FILTER(Doctorate Thesis)Abdullah TOPRAKGAZİ UNIVERSITYINSTITUTE OF SCIENCE AND TECHNOLOGYSeptember 2006ABSTRACTMedian filter is an image filter that is more effective in situations where theimpulse noise is less than 0.2. If this ratio exceeds 0.2, adaptive median filter isused. As is the case in other filters, a Sxy window is selected for the adaptive medianfilter. However a feature that differentiates the adaptive median filter from theother filters is the fact that the size of this window can be changed. Unfortunately,while adaptive median filter removes the impulse noise, it also deteriorates thedetails in the image it accompanies. In order to prevent this, the pixel values of theimage are determined by the fuzzy adaptive median filter, and as such Rule basedfuzzy adaptive median filter (KTBAMF) is defined in this study. KTBAMF filter ismade up of three basic sections. These are decision units that decide on whether ornot there are median filter, fuzzy logic rules and noise. The basic purpose of usingthis filter is while destroying the noise on the image; it prevents the details of theimage from disappearing. It is for this reason that KTBAMF is an effective filter indestroying the impulse noise. The KTBAMF filter is an improved version ofAdaptive Median Filter (AMF) and is presented in the aim of noise reduction ofimages corrupted with additive impulse noise. In this paper, we placed ourpreference on bell-shaped membership function instead of triangular membershipfunction in order to observe better results.Science Code : 704Key Words : Median Filter, Fuzzy Logic, Impulse Noise, Image ProcessingPage Number : 81Adviser : Prof. Dr. İnan GÜLER