GLSL (v2.0 Release Candidate 5) Experimental
Pre-release
Installation Instructions for GLSL/MPV Version
Replaced the Bilateral Mean Filter with a "Regularized" Bilateral Mode Filter. The mode is more robust than the mean or median, and introduces the least amount of blur.
The mode filter needs to be "regularized" since the mode of a set is not defined when the number of data points is finite and contains unique data (all data points are different). This undefined case happens extremely often in images when using a small kernel (eg. 3x3), since there are 256 possible luma values, but only 9 samples. Often all 9 pixels will have different values, and rigging up a continuous fallback to median/mean that does not introduce discontinuities is not trivial.
However, we can use Kernel Density Estimation (KDE) as a continuous approximation of the discrete probability color histogram.