function [Centroids] = centroids(dirName)
% calculate the centroids of the 3 largest skin-colored
% blobs in all the images in the given directory
% make a quicktime movie highlighting them
%quicktime init
MakeQTMovie('start', [dirName '/' 'tracking.mov']);
MakeQTMovie('quality', 1.0);
MakeQTMovie('size', [360 243]);
MakeQTMovie('framerate', 30);

fileNames = dir([dirName '/' '*.tif']);
numFiles = length(fileNames);

Centroids = zeros(3 * numFiles, 2);

for i = 1:numFiles
    fileName = fileNames(i).name
    [s b c o] = color_segment([dirName '/' fileName]);
    Ret = blob2(s)
    startCen = (i-1) * 3 + 1;
    endCen = (i - 1) * 3 + 3;
    Centroids(startCen:endCen, 1:2) = Ret;    

    
    figure(1);
    MakeQTMovie('addframe');
end

MakeQTMovie('finish'); %finish the quicktime movie