RPNR | Render Pass Noise Reduction is a noise-reduction algorithm

RPNR is a C++ library. RPNR has no bugs, it has no vulnerabilities and it has low support. However RPNR has a Non-SPDX License. You can download it from GitHub.

Many ideas on how to reduce noise in a Blender Cycles render just work off the resulting image and focus on removing fireflies by blurring the image and then regrouping the pixels in some clever way. Some try to do edge detection, but in the end, we mostly end up with some algorithm that will blur a lot of the edges of the surfaces. Then it hit me: a Blender render has multiple render passes that can be exported to us virtually for free and some of these passes are either noiseless or noiseless with some aliasing. My proposal is to make use of those render passes to better detect the edges of surfaces in a render and offer more context to the de-noising algorithm.