Ok, I found the bug that made the filter unstable after outputting few lines.
It is caused by the noise addded by the normalization process that raises exponentially in the unblurring process.
I have to find a workaround for it.
More infos can be found in the new release (readme.htm)
I worked out some bugs since last release, but still can't find the bug in the denormalizing loop. Help is appreciated.