17-9 Color-image denoising method with the redundant DCT of adaptive block-size and the color shrinkage

Abstract

Previously, we have proposed the l^1-l^2 color shrinkage scheme utilizing inter-channel cross-correlations. We have shown that the l^1-l^2 color shrinkage scheme is useful for denoising color images not only in the redundant wavelet transform domain but also in the redundant DCT domain. However, as for the color-image denoising in the redundant DCT domain, color smears often remain when the block size of the DCT is set small. On the other hand, noise in the vicinity of sharp color-edges is little removed when the block size of the DCT is set large. To alleviate these drawbacks, this paper introduces the redundant DCT of adaptive block-size into the color-image denoising method, and experimentally demonstrates its improvements.