How to construct a feature matrix X where rows correspond to pixels and columns correspond to features?

I have converted the image from RGB color space to Lab color space using rgb2lab function.

Now I need to represent each pixel via its Lab color values. Construct a feature matrix X where rows correspond to pixels and columns correspond to features.

Which function I need to use? How can I do that?

Answer 1

[Image Analyst]

What are the features? The lab values? Have you tried just using brackets and parentheses?

labImage = rgb2lab(rgbImage);
lImage = labImage(:,:,1);
aImage = labImage(:,:,2);
bImage = labImage(:,:,3);
featureMatrix = [lImage(:), aImage(:), bImage(:)]