Hi Fiona,
how about labeling image? The following code is the example.
%% image load
img = double(rgb2gray(imread('coloredChips.png'))) / 255.;
img(randperm(numel(img), round(numel(img)/100))) = NaN;
figure;
imshow(img);
%% labeling
label = zeros(size(img), 'uint8');
label(~finite(img)) = 0;
label(img < 0.05) = 1;
label(img >= 0.05 & img <= 0.2) = 2;
label(img > 0.2) = 3;
figure;
imshow(label, []); colormap(jet);
%% make colormap
map = [1 1 1; % white for 0
1 0 0; % red for 1
1 1 0; % yellow for 2
0 1 0 ]; % green for 3
%% converting to rgb image
rgb = ind2rgb(label, map);
figure;
imshow(rgb);
Hope this helps.
