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Color conversion RGB to Lab

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med BT
med BT on 6 Mar 2017
Commented: med BT on 6 Mar 2017
Hello, I want to convert a RGB image to L*a*b*, I did some research and I found two different codes, and the results are also differents.
1st code :
src = 'Img1.jpg';
rgbI = imread(src);
labI=rgb2lab(rgbI);
imshow(labI(:,:,1),[0 100])
2nd code :
src = 'shad.jpg';
rgbI = imread(src);
labTransform = makecform('srgb2lab');
labI = applycform(rgbI, labTransform);
imshow(labI)
Could you please tell me which one is the correct conversion.
  2 Comments
med BT
med BT on 6 Mar 2017
I work on the same image

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Answers (1)

Stephen Cobeldick
Stephen Cobeldick on 6 Mar 2017
Edited: Stephen Cobeldick on 6 Mar 2017
The makecform default illuminant is ICC, but sRGB uses D65. So you need to specify the correct whitepoint for that conversion
makecform('srgb2lab', 'AdaptedWhitePoint', whitepoint('D65'))

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