Brian Thorne skrev: > I made a pretty (IMHO) plot of the diff image seperating each channel: > http://1.bp.blogspot.com/_lewp47C9PZI/SqJSUG7MJEI/AAAAAAAAAgs/s8aSE0FBCwI/s1600-h/lena_diff_ndfilt_iir.png Can you post the code for this so I could check a couple of things? Sturla Molden