x = imread('cameraman.tif');
watermark = imread('C:\Users\areee\Desktop\watermark.png');
x = imresize(x,[512 512]);
watermark = imresize(watermark,[512 512]);
watermark = im2bw(watermark);
I = x;
img_blocks = mat2cell(I,size(I,1)/4*ones(1,4), size(I,2)/4*ones(1,4));
part1 = dct2(img_blocks{1,1});
part2 = dct2(img_blocks{1,2});
part3 = dct2(img_blocks{1,3});
part4 = dct2(img_blocks{1,4});
part5 = dct2(img_blocks{2,1});
part6 = dct2(img_blocks{2,2});
part7 = dct2(img_blocks{2,3});
part8 = dct2(img_blocks{2,4});
part9 = dct2(img_blocks{3,1});
part10 = dct2(img_blocks{3,2});
part11= dct2(img_blocks{3,3});
part12 = dct2(img_blocks{3,4});
part13 = dct2(img_blocks{4,1});
part14 = dct2(img_blocks{4,2});
part15= dct2(img_blocks{4,3});
part16 = dct2(img_blocks{4,4});
I = watermark;
img_blocks = mat2cell(I,size(I,1)/4*ones(1,4), size(I,2)/4*ones(1,4));
partW1 = dct2(img_blocks{1,1});
partW2 = dct2(img_blocks{1,2});
partW3 = dct2(img_blocks{1,3});
partW4 = dct2(img_blocks{1,4});
partW5 = dct2(img_blocks{2,1});
partW6 = dct2(img_blocks{2,2});
partW7 = dct2(img_blocks{2,3});
partW8 = dct2(img_blocks{2,4});
partW9 = dct2(img_blocks{3,1});
partW10 = dct2(img_blocks{3,2});
partW11= dct2(img_blocks{3,3});
partW12 = dct2(img_blocks{3,4});
partW13 = dct2(img_blocks{4,1});
partW14 = dct2(img_blocks{4,2});
partW15= dct2(img_blocks{4,3});
partW16 = dct2(img_blocks{4,4});
newP1 = part1+partW1;
newP2 = part2+partW2;
newP3 = part3+partW3;
newP4 = part4+partW4;
newP5 = part5+partW5;
newP6 = part6+partW6;
newP7 = part7+partW7;
newP8 = part8+partW8;
newP9 = part9+partW9;
newP10 = part10+partW10;
newP11 = part11+partW11;
newP12 = part12+partW12;
newP13 = part13+partW13;
newP14 = part14+partW14;
newP15 = part15+partW15;
newP16 = part16+partW16;
newP1 = idct2(newP1);
newP2 = idct2(newP2);
newP3 = idct2(newP3);
newP4 = idct2(newP4);
newP5 = idct2(newP5);
newP6 = idct2(newP6);
newP7 = idct2(newP7);
newP8 = idct2(newP8);
newP9 = idct2(newP9);
newP10 = idct2(newP10);
newP11 = idct2(newP11);
newP12 = idct2(newP12);
newP13 = idct2(newP13);
newP14 = idct2(newP14);
newP15 = idct2(newP15);
newP16 = idct2(newP16);
total = [newP1,newP2,newP3,newP4;newP5,newP6,newP7,newP8;newP9,newP10,newP11,newP12;newP13,newP14,newP15,newP16];
imshow(total,[]);
