epmat(linspace(1,0,size(cm,1))',1,2);
X = repmat(1:size(I,2),size(I,1),1);
Y = repmat([1:size(I,1)]',1,size(I,2));

<span class="comment">%{
</span><span class="comment">figure;
</span><span class="comment">imagesc(I);colormap(cm)
</span><span class="comment">set(gca,'XTickLabel','')
</span><span class="comment">set(gca,'YTickLabel','')
</span><span class="comment">axis([0,29,0,29]);
</span><span class="comment">%}
</span><span class="comment">%sigs = [0.1 1 8];</span>
sigs = [5 5 5 5]; <span class="comment