Oh wait, I think I misread this, the description says:
Each pixel in the image is characterized by the colors of the rays that reach its surface. The proposed filter uses a statistical distance to compare with each other the ray color distributions associated with different pixels, at each scale. Based on this distance, it decides whether two pixels can share their rays or not.
So, that sounds indeed like some kind of interpolation.
Anyways, It would be awesome for animations. Rendering stuff without pre-baking and such reduced render times is such a cost and time saver that it's even worth some little artifacts if there should be some. For me, it sounds like a way to make pathtracing useful for production ;)
