ckt = imread('ckt-board-orig','pgm');
imshow(ckt);
figure();
ckt_dct = dct2(ckt);
imshow(log(abs(ckt_dct)),[]),colormap(hsv),colorbar;
figure();
ckt_dct_lossy = ckt_dct;
ckt_dct_lossy(301:600,:) = eps;
ckt_dct_lossy(:,301:600) = eps;
imshow(log(abs(ckt_dct_lossy)),[]),colormap(hsv),colorbar;
figure();
ckt_lossy = idct2(ckt_dct_lossy);
imshow(ckt_lossy,[0 255]);
figure();
ckt_dct_lossy2 = ckt_dct;
ckt_dct_lossy2(151:600,:) = eps;
ckt_dct_lossy2(:,151:600) = eps;
imshow(log(abs(ckt_dct_lossy2)),[]),colormap(hsv),colorbar
figure();
ckt_lossy2 = idct2(ckt_dct_lossy2);
imshow(ckt_lossy2,[0 255]);