Salt and pepper noise reduction using mdbutm filter with fuzzy based refinement

A Modified Decision Based Unsymmetrical Trimmed Median Filter (MDBUTMF) followed by Fuzzy Noise Reduction Method (FNRM) is proposed for the restoration of color images that are highly corrupted by salt and pepper noise. The proposed filter (MDBUTMF) replaces the noisy pixel by trimmed median value when some of the elements with values 0’s and 255’s are present in the selected window. If all the pixel values in the selected window are 0’s and 255’s means then the noisy pixel is replaced by mean value of all the elements present in that selected window. The throughput of MDBUTMF is a partial noise removed image. It is further processed by FNRM. The FNRM has two sub-filters. The first sub-filter computes fuzzy distances between the color components of the central pixel and its neighborhood. The target of the second sub-filter is to correct the corrupted pixels. The throughput of FNRM is a fully noise removed image. Simulation results show the feasibility of the proposed method. The proposed method is tested against different color images and it gives excellent Peak Signal-to-Noise Ratio (PSNR) than the Median Filter (MF), Switching Median Filter (SMF), Boundary Discriminative Noise Reduction Algorithm (BDNRA), Decision Based Algorithm (DBA), and Decision Based Unsymmetric Trimmed Median Filter (DBUTMF).