viola jones - threshold to determine Haar Feature

Question

I try now to understand the Viola-Jones algorithm and I get confused about the threshold to determine if a block a Haar feature or not. The intensity of a pixel is in the range of 0->255.

When we have an ideal Haar feature then the delta value is 255 (like the image on the left) but in a real image, for example on the right, delta is 146, is that a Haar feature?

my question is: which value is the threshold value to determine if a block a Haar feature or not? Or it is simply 255/2=127,5? When delta > 127.5 -> Haar feature, when delta < 127.5 -> no Haar feature?

question from:https://stackoverflow.com/questions/65877139/threshold-to-determine-haar-feature

Answer 1

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