If I were going to be calculating brightness to say, determine if a pixel meets a threshold, what is the most effective method in terms of speed and efficiency? I would be doing it for video, so it would need to be somewhat fast.
The two models I’ve seen are Luma and HSP, and HSP seems to be far too processing intensive to do fast-enough calculations for video. Am I wrong?
Luma is calculated by:
Brightness = 0.299 r + 0.587 g + 0.114 b
HSP is more accurate, using weighted 3D space:
brightness = sqrt( .241 R^2 + .691 G^2 + .068 B^2 )
What is generally what is used in most brightness calculations?
PS. I’m aware that there is already a threshold method in BitmapData. I want to write my own 
