fix coefficients for detecting brightness #32
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The formula using to calculate relative luminance (or brightness):
Y = 0.299 R + 0.587 G + 0.114
But it is correct in NTSC (1953) color space only. This formula is deprecated and legacy.
Actual color space sRGB significantly different: chromacity diagram.
Correct formula is:
Y = 0.2126 R + 0.7152 G + 0.0722 B
The proof of numbers
Source — Bruce Lindbloom site
See also — Charles Poynton Color FAQ
A lot of work or refactoring is not required. We can simply replace this coefficients.