Combined Fuzzy Logic and Unsymmetric Trimmed Median Filter Approach for the Removal of High Density Impulse Noise

In this paper, a combined fuzzy logic and unsymmetric trimmed median filter approach is proposed to remove the high density salt and pepper noise in gray scale and colour images. This algorithm is a combination of decision based unsymmetrical trimmed median filter and fuzzy thresholding technique to preserve edges and fine details in an image. The decision based unsymmetric trimmed median filter fails if all the elements in the selected window are 0’s or 255’s. One of the possible solutions is to replace the processing pixel by the mean value of the elements in the window. This will lead to blurring of the edges and fine details in the image. To preserve the edges and fine details, the combined fuzzy logic and unsymmetric trimmed median filter approach is proposed in this paper. The better performance of the proposed algorithm is demonstrated on the basis of PSNR and IEF values. Key-Words: Fuzzy logic, Fuzzy threshold, Salt and Pepper noise, Decision based Unsymmetric Trimmed Median Filter, Membership function, Noise reduction.