Hi,
Here is a sample code which you can use for digital watermarking using KLT transform in using MATLAB:
% Read the original image
I = imread('original_image.jpg');
% Convert the image to grayscale
I_gray = rgb2gray(I);
% Generate the watermark image
W = rand(size(I_gray)) > 0.5;
% Perform KLT transform on the original image
C = dct2(I_gray);
% Calculate the covariance matrix
R = cov(C);
% Calculate the eigenvalues and eigenvectors
[V,D] = eig(R);
% Sort the eigenvalues in descending order
[~,ind] = sort(diag(D),'descend');
V = V(:,ind);
% Use the first N eigenvectors to embed the watermark
N = 5;
W_embedded = C + 0.1*W.*repmat(V(:,1:N)*V(:,1:N)',size(C,1),size(C,2));
% Perform inverse KLT transform
I_watermarked = idct2(W_embedded);
% Display the original and watermarked images
figure;imshow(I_gray);title('Original Image');
figure;imshow(I_watermarked);title('Watermarked Image');
