K-Means on RGB image

kmeans.m

optns = statset('MaxIter', iters);
pixels = reshape(img(:), [], 3);

[idxs, centroids] = kmeans(pixels, k, 'options', optns);

img_map = centroids(idxs, :);
img_new = reshape(img_map(:), size(img));

imshow(img_new);