Enhancement of noisy images with sliding discrete cosine transform

Abstract

Enhancement of noisy images using a sliding discrete cosine transform (DCT) is proposed. A minimum mean-square error estimator in the domain of a sliding DCT for noise removal is derived. This estimator is based on a fast inverse sliding DCT transform. Local contrast enhancement is performed by nonlinear modification of denoised local DCT coefficients. To provide image processing in real time, a fast recursive algorithm for computing the sliding DCT is utilized. The algorithm is based on a recursive relationship between three subsequent local DCT spectra. Computer simulation results using a real image are provided and discussed. © Springer-Verlag Berlin Heidelberg 2005.