Watermarking Techniques Review

In today's corporate world, millions of images are travel widely and rapidly, in multiple manifestations, through email and across the Internet. Controlling and protecting sensitive or confidential documents and images has become very important now days.A digital watermark is a digital signal or pattern inserted into a digital image. A given watermark may be unique to each copy (e.g. to identify the intended recipient), or be common to multiple copies. In either case, the watermarking of the document involves the transformation of the original into another form. In this paper we aim to present a review of different techniques on digital image watermarking.Digital watermark techniques are used in various areas such as copyright protection, broadcast monitoring and owner identification. This review elaborates the most important methods of spatial domain and transform domain like DCT, DFT, DWT, and focuses the merits and demerits of these techniques