Marc FD wrote: >> The only? Hardly :) > > What do you mean ?? There are a whole lot of objective measures. Check www.vqeg.org for instance. My personal favourite (because of its simplicity) is Zhou Wang's structural distortion measure. See : http://anchovy.ece.utexas.edu/~zwang/research/quality_index/demo.html http://anchovy.ece.utexas.edu/~zwang/papers/icip02b.html Marco