Jinrong Hu Yi-Fei Pu Xi Wu Yi Zhang Jiliu Zhou Improved DCT-Based Nonlocal Means Filter for MR Images Denoising. 2012 2012 Comp. Math. Methods in Medicine http://dx.doi.org/10.1155/2012/232685 db/journals/cmmm/cmmm2012.html#HuPWZZ12