Coloring the largest component with different color than others

Hello all,

I am looking to mark the largest connected component in an image with special color say 'red', and then color the other components in black while the empty space I wanted to be colored in white.Here are my codes.

[Sultan]

   A=rand(100);
     B=A<.5
     CC = bwconncomp(B,4)
   numOfPixels = cellfun(@numel,CC.PixelIdxList)
   [unused,indexOfMax] = max(numOfPixels)
   biggest = zeros(size(B))
   biggest(CC.PixelIdxList{indexOfMax}) = 1

        colours=[1 1 1;1 0 0;0 0 0]
colormap (colours)

     imagesc(biggest)

Answer 1

[Prashant Arora]

Hi Sultan,

You can use the method below to achieve your use-case.

image = zeros(size(biggest,1),size(biggest,2),3);
NotBiggest = B - biggest;
image(:,:,1) = biggest + 1*NotBiggest;
image(:,:,2) = 0*biggest + 1*NotBiggest;
image(:,:,3) = 0*biggest + 1*NotBiggest;
imagesc(image);