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Topic: luminance==brightness() ??? (Read 402 times) |
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sspboyd
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luminance==brightness() ???
« on: Apr 28th, 2004, 1:20am » |
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I just spent a wack of time writing some code to sort a bunch of image slices according to their average luminance values (luminance=0.3*R+0.6*G+0.1B, http://cnx.rice.edu/content/m11084/latest/ ).
Having done this, I am wondering what the difference is (if any) between calculating the luminance of a pixel versus getting it's brightness with the brightness() function (or is it a method, I don't know).
How is brightness calculated with brightness()?
thanks,
steve
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gmail.com w/ sspboyd username
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Quasimondo
 
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Re: luminance==brightness() ???
« Reply #1 on: Apr 28th, 2004, 10:57am » |
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If you convert RGB to HSV (Hue/Saturation/Value, also called HSB, B for Brightness), the Brightness is defined as:
max (red, green, blue);
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Mario Klingemann | Quasimondo | Incubator | côdeazur
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fry
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Re: luminance==brightness() ???
« Reply #2 on: Apr 28th, 2004, 1:37pm » |
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yep, and that's how the brightness() calculation is done (since it's part of the hsb calc). luminosity is in fact different, though their intent/use is often identical.
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