2

I've come across code to calculate a Dice coefficient in imaging segmentation, in which a "smoothing factor" was added to the formula, as below (pseudo-code):

sf = 1    
Dice = [2 (A * B) + sf] / [(A + B) + sf]

What would be the purpose of this and its effect on the output of Dice coefficient?

pecorino
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  • Probably sf insures against zero denominator? But the thing with your question is that Dice, as I know, has different formula from yours (see e.g. http://stats.stackexchange.com/a/55802/3277 ). – ttnphns Apr 04 '17 at 15:56
  • that's interesting, from https://en.wikipedia.org/wiki/Sørensen-Dice_coefficient it seems `2` should be multiplied by the sum of numerator (intersection), do you agree? – pecorino Apr 04 '17 at 16:00

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