Image denoiser help please

[DrPhill]

Could anyone point me to a good source of information on image denoisers. I would like to write one in order to understand the principle.

Also any pointers to good articles on blur/sharpen algorithms would be gratefully received.

Anything I write will make it into Gorp - a free video editor that will go open source under GPL as soon as the code stabilises.

Thanks in advance for any help.

Phill