Noise Shampoo 3 is an edge-preserving smoothing filter. It can be used to reduce noise on pictures, or to simplify them.
version 2: new algorithm variation, that leads to more photo realistic results. You can now select a separate clean strength for chroma & luminosity. Speed improvement (multithreading) , and improved memory usage.
version 3: implicitly comes with a fourth algorithm. But now algorithms are presented differently, you have instead two "quality tweaks", which leads to four combinations. The "Anti Edge Loss" setting was dropped.