Denoising in the lapped transform domain
In this paper, we extend the results of the denoising in the wavelet domain to the lapped transform (LT) domain. The LT coefficients are rearranged into the octave based representation, and their statistics are modeled by the same methods as the wavelet coefficients. Since the part of the LT that follows the discrete cosine transform (DCT) is orthogonal, the problem of removing the quantization noise introduced in the DCT based codecs can be solved in the LT domain. The maximum a posteriori (MAP) estimator is obtained, which provides a novel approach to the image compression artifact reduction problem. The proposed method removes the additive noise and the quantization noise effectively with the significant improvement of image quality.