img = double (imread ('berndsface.png'));
folder = 'C:\Users\HP\Documents\Laboratory Matlab\Laboratory 25\';
h = [1, 0; 0, -1];
filteredImg1 = imfilter (img, h', 'replicate');
filteredImg1 = log (abs (filteredImg1) + 1 );
filteredImg1 = filteredImg1 /max(filteredImg1 (:));

h = [0, 1; -1, 0];
filteredImg2 = double (imfilter (img, h, 'replicate'));
filteredImg2 = log (abs (filteredImg2) + 1 );
filteredImg2 = filteredImg1 /max (filteredImg2 (:));

figure(5); clf;
subplot (2, 4, 1), imshow (uint8 (img)); title ('Original');
subplot (2, 4, 2), imshow (filteredImg1); title ('Roberts Horizontal');
subplot (2, 4, 3), imshow (filteredImg2); title ('Roberts Anti- Diagonal');
imwrite (filteredImg1,strcat(folder, 'Roberts_face_verticall.png'));
imwrite (filteredImg2,strcat(folder, 'Roberts_face_horizontal.png'));

% Roberts
% Apply Roberts filter in two directions

img = double (imread ('berndsface.png'));
h = [1, 0; 0, -1];
filteredImg1 = imfilter (img, h', 'replicate');
h = [ 0, 1; -1, 0];
filteredImg2 = double (imfilter (img, h, 'replicate'));

% Threshold based on edge magnitude response

 edgeSum = filteredImg1 .^2 + filteredImg2 .^2;
logEdgeSum = log (edgeSum + 1);
logEdgeSum = logEdgeSum / max (logEdgeSum (:));
bwEdge1 = edgeSum > 100;
bwEdge2 = edgeSum > 500;
bwEdge3 = edgeSum > 800;

% Show and save images
subplot (2, 4, 5), imshow (logEdgeSum); title ('Edge Magnitude');
subplot (2, 4, 6), imshow (bwEdge1); title ('Magnitude > 100');
subplot (2, 4, 7), imshow (bwEdge2); title ('Magnitude > 500');
subplot (2, 4, 8), imshow (bwEdge3); title ('Magnitude > 800');
imwrite (logEdgeSum,strcat(folder, 'Roberts_face_logEdgeSum.png'));
imwrite (bwEdge1,strcat(folder, 'Roberts_face_bwEdge1.png'));