Authentication Watermarking Algorithm based on Quad-tree Decomposition

Analyzed the manners of content-based image authentication and methods of tamper location,and proposed a watermarking algorithm for image authentication based on image quad-tree decomposition.The graphical result of quad-tree decomposition has been used to be watermark image and help to find out the tampered areas.Experiment result shows that this method can resist common image processing and also detect and locate evil intentioned attacks on the precondition of holding the visual quality of images.