DeSpot Filter Question

[mcpogue]

Does anyone know what measurement the DeSpot filter for AviSynth uses to determine pixel values? Is it luma, chroma, or some other value? For example, it says in the that a pixel must differ from its neighbors by at least p1
to be considered noise. Let's assign p1 a value of 30. My question is: 30 what? 30 on a scale from 0-255 luma?
or some other value like chroma or intensity or saturation? Would there be any way to determine what pixel values the filter is assigning to portions of the video? For example, if a group of pixels that we call a spot have a value of around 64 and its neighbors 24 then p1 would = 40 What I'm asking is: Is there a more accurate way to tune the parms in DeSpot than starting with the default values and spending hours on trial and error, hit and miss guessing at
appropriate settings?

[mcpogue]

From lokking at the readme, it looks like lumanance is what is being measured on a scale of 0-255. I guess a waveform monitor like the one in color tools would be the only way to objectively measure average and peak luma values, either that or a histogram.