Derive a colour palette from an image

Question

Andy 2013-4-12

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/71779-derive-a-colour-palette-from-an-image

I have a question which asks to set the number of rows and columns (M and N) for the painting grid and resize an image to this required gridsize.

I used imresize like below, where B is my image.

B = imresize(B,[20,20]);

It then says use this command to derive the 8 colour palette.

[~, Palette] = kmeans(reshape(B(:),M*N,3),8,'E','s','S','U');

If i replace M and N with my grid values which are 20 and 20 i get this error, for the line above.

Error using  .* 
Integers can only be combined with integers of the same class, or scalar doubles.
Error in unifrnd (line 34)
r = mu + sig .* (2*rand(sizeOut)-1);
Error in kmeans (line 248)
            C = unifrnd(Xmins(ones(k,1),:), Xmaxs(ones(k,1),:));