Is sharpen = USM or something else.

jstuartj

Is sharpen functionally equivalent to  Photoshop's USM: where sharpened = original + (original − blurred) × amount?

If not would it be possible to get an implementation of Unsharp-masking.

SamuelMorris

Hi @jstuartj, I'm not sure if it's identical, but the "Sharpen" plugin does work on a similar idea at least.