Effective detection and elimination of impulse noise for reliable 4:2:0 YCbCr signals prior to compression encoding

This paper presents an efficient two-stage filtering method that provides highly reliable 4:2:0 YCbCr signals, which are widely used in the image- and video-processing community. In the first phase, we use an index mapping, center-weighted median filter (IMCWMF) to detect and remove noise from luminance (Y) components while inheriting the chrominance components (Cb and Cr) for the selected median luminance. In the second phase, we use a downsampling sigma filter (DSF) to detect and remove noise from the chrominance components while performing the downsampling process. Simulation results indicate that the proposed method outperforms other nonlinear filters in terms of both noise attenuation and signal-detail preservation while providing accurate color channel information for the JPEG compression process and overall image quality.