SpatialCues.m

function [hC vC] = SpatialCues(im)
g = fspecial('gauss', [13 13], sqrt(13));
dy = fspecial('sobel');
vf = conv2(g, dy, 'valid');
sz = size(im);

vC = zeros(sz(1:2));
hC = vC;

for b=1:size(im,3)
    vC = max(vC, abs(imfilter(im(:,:,b), vf, 'symmetric')));
    hC = max(hC, abs(imfilter(im(:,:,b), vf', 'symmetric')));
end