% Created by Majed El Helou (2017)
% All rights reserved for EPFL.

function [ sobel ] = sharpnessSobel( result )
%sharpnessSobel computes a sharpness measure that we base on the Sobel
%differentiation gradients


    sobel_h = fspecial('sobel');   %detects horizontal edges
    sobel_v = fspecial('sobel').'; %detects vertical edges

        % Evaluate sharpness through Sobel differentiation imgradient
        np = size(result,1) * size(result,2);
    
        D_Ih = abs( conv2(result, sobel_v, 'same') );
        D_Iv = abs( conv2(result, sobel_h, 'same') );
        sobel = sum(sum( D_Ih + D_Iv ));
        sobel = sobel / np;

end