clear all; 

a = [1 1 0 0 0 0 1 1 1 0 0;
     1 1 0 0 0 0 1 1 0 0 0;
     0 0 1 1 0 0 0 1 1 0 0;
     0 0 1 1 0 0 0 1 1 0 0;
     0 0 0 0 0 0 1 0 0 0 0;
     0 0 0 0 0 0 1 0 0 0 0;
     0 0 0 0 0 1 1 1 0 0 1];
 
cc = bwlabel(a, 4); % 4-neighbors
% Examine pixels to see the labels
imtool(cc);

% View with color and the default colormap
ccImg = label2rgb(cc);
imtool(ccImg);

% View with a specific colormap and black background
ccImg = label2rgb(cc, @jet, 'k');
imtool(ccImg);

% REPEAT WITH 8-neighbors
cc8 = bwlabel(a, 8); 
cc8Img = label2rgb(cc8, @jet, 'k');
imtool(cc8Img);

% Place pixels from region 2 into a mask
mask = zeros(size(cc));
mask ( find (cc == 2)) = 1

% Count pixels from a single region
size(find(cc == 2))

% get coords of pixels from a single region
[x,y] = find(cc == 3)

% Find centroid (you do)