SVD Domain watermarking

Pseudo-code (Algorithm to implement)
[U1,S1,V1] = svd(A); // A is cover image
temp = S1+(a * W); // a is scaling factor, and W is watermark
[Uw,Sw,Vw] = svd(temp);
Aw = U1*Sw*(V1.'); // Aw is watermarked image
Extraction of watermark in SVD domain
[Uw1,Sw1,Vw1] = svd(Aw);
D = Uw*Sw1*(Vw.') //temp;
W = (D-S1)/a;