matlab 添加水印

%Abhijith. S, PAACET, India. %Implementing Watermarking using discrete 2-D wavelet transform. %Input image is watermarked with a key having Mean = 0 & Variance = 1 clc;clear all;close all; img = imread('home.jpg'); %Get the input image img = rgb2gray(img); %Convert to grayscale image img = double(img); c = 0.01; %Initialise the weight of Watermarking figure,imshow(uint8(img)),title('Original Image'); [p q] = size(img); %Generate the key n = awgn(img,4,3,'linear'); N = imabsdiff(n,img); figure,imshow(double(N)),title('Key'); [Lo_D,Hi_D,Lo_R,Hi_R] = wfilters('haar');%Obtain the fiters associated with haar [ca,ch,cv,cd] = dwt2(img,Lo_D,Hi_D); %Compute 2D wavelet transform %Perform the watermarking y = [ca ch;cv cd]; Y = y + c*abs(y).* N; p=p/2;q=q/2; for i=1:p for j=1:q nca(i,j) = Y(i,j); ncv(i,j) = Y(i+p,j); nch(i,j) = Y(i,j+q); ncd(i,j) = Y (i+p,j+q); end end %Display the Watermarked image wimg = idwt2(nca,nch,ncv,ncd,Lo_R,Hi_R); figure,imshow(uint8(wimg)),title('Watermarked Image'); diff = imabsdiff(wimg,img); figure,imshow(double(diff));title('Differences');