clear all;
close all;
clc;

%%加水印
img = double(imread('lena.jpg'));
wm = double(imread('watermark.png'));
imshow(wm);

fimgre = fft2(img) + wm*10;
imgre = uint8(real(ifft2(fimgre)));

figure;
imshow(imgre);
imwrite(imgre,'lena_watermark.png');

%%解水印
img = double(imread('lena.jpg'));
img_watermark = double(imread('lena_watermark.png'));
wm = fft2(img_watermark) - fft2(img);

figure;
imshow(mat2gray(real(wm)/10));
imwrite(mat2gray(real(wm)/10),'re.png');