CAT12 SANLM denoising filter expert parameter description

Hello NeuroStars,

I’m having a hard time understanding the meaning of some parameters of the SANLM denoising filter in CAT12. In short, I’m trying to disable the intentional limitations in order to maximize noise removal. The two parameters that confuse me are:

  1. Strength of relative intensity adaptation: “[…] Hence, a relative limitation of SANLM correction is added here that is based on the bias reduced image intensity.”
    So is this parameter controlling the limitation of noise correction, so that for full noise correction I should set this to 0? Or is it some other kind of intensity adaptation and the limitation mentioned here is actually applied by the following parameter?
  2. Factor of relative filter strength limit: “Limit the relative noise correction to avoid over-filtering of low intensity areas. Low values will lead to less filtering in low intensity areas, whereas high values will be closer to the original filter. INF deactivates the filter.”
    It sounds like 0 would disable noise filtering completely in low intensity areas, so if I want full noise correction I should put a large number. But the last sentence doesn’t make sense. Should it read instead: “INF deactivates the limitation”?

Also, out of curiosity, how come this takes a minute to run, while the implementation by the original authors (AONLM) takes 40 minutes to run? Is it mainly due to having a very different stopping criterion in an iterative process?