This a secure and robust watermarking scheme based on singular values replacement and IWT transformation.
The technique is described in the following paper: https://github.com/shreyverma03/Robust-Watermarking-2/blob/master/IWT(SVd).pdf
What it does and how to use it:
If you just want to hide a logo "let's say a watermark message (a.k.a image)" inside another image then simply open "iwt_svd.m"
Finally execute the dwt_svd.m from matlab command window and watch the figures.
Decomposition upto 1st step-4th step can be done by executing "iwt_svd.m".
Watermarked Image , Watermark Logo , Extracted Watermark all can be viewed by executing "iwt_svd.m".