Finding l a b of a specific colour

Question

Noah Noah 2022-3-15

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回答： Image Analyst 2022-3-15

Hello, I need to know what the respective average l a b components are of a lab colour space of specific colours.

I have white = [255,128,128] and I'm unsure what the lab components are of blue,yellow,green and red.

Could someone help me find out how to get them please?

Thank you.

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Answer 1

Image Analyst 2022-3-15

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That is not white - it's pink. To get the CIE LAB values, using book formulas, then it depends if your numbers are floating point or integers. If they're doubles, you must divide by 255 (that's why the answer from @_ didn't work).

% If values are doubles, you must get them into a range of 0-1 by dividing by 255:
lab_pink = rgb2lab([255,128,128] / 255)
lab_pink = 1×3
   68.2137   48.1889   22.6959
% If values are uint8 then no scaling is needed:
lab_pink = rgb2lab(uint8([255,128,128]))
lab_pink = 1×3
   68.2137   48.1889   22.6959