Constructing Digital Watermark Based on Orthogonal Functions

摘要

This paper proposes a double digital watermarking system which is capable of embedding two different digital?private images into one ordinary image. This new system has two main features. First, two digital private images can be?reproduced from one digital watermark image, so twice the number of digital private images can be transmitted simultaneously as confidential information. Second, since this double digital watermark is constructed using two different characteristics of orthogonal functions, it is also possible to detect whether or not someone has altered the digital file.