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I have to create a lightness histogram of an image. I have already maked a RGB Histogram

On Internet i found these values:

Luminance (standard, objective): (0.2126*R) + (0.7152*G) + (0.0722*B)

Luminance (perceived option 1): (0.299*R + 0.587*G + 0.114*B)

Luminance (perceived option 2, slower to calculate): sqrt( 0.241*R^2 + 0.691*G^2 + 0.068*B^2 )

I make lightness histogram throught these values or luminance is a different stuff?

Or maybe i use java libraries with methods to take L value (lightness) from a Lab space, converting the sRGB space?

postgres
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1 Answers1

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As far as I know, the Luminance formula you listed are used to describe Perceived brightness. Luminance is also used in the video industry to characterize the brightness of displays.

Since you have hist(R), hist(G), hist(B) already, it's easy to do a linear transform into Luminance using the first two formulas. Try to plot the resulting Luminance chart for some images you have. The best way is always to try and see the difference.

greeness
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