function saveFeatures(imgfilename,n)

if(nargin<2)
    n=43;
end

img = imread(imgfilename);
figure;imshow(img);
[x,y] = ginput(n);
xy = [x y];

asciifilename = [imgfilename(1:find(imgfilename=='.',1,'last')) 'txt'];
save(asciifilename, 'xy', '-ascii');

