ABSTRACT
This chapter introduces a multidimensional watermark scenario. It presents the process of multidimensional watermark embedding and introduces the watermark detection, hypothesis testing, and joint probability distribution. The methods for image watermarking can be classified into two categories: the spatial domain approach and the transform domain approach. The watermark information to be sent from the sender to the receiver is spread by a pseudorandom sequence and transmitted through a special channel. Similar to spread spectrum communication, the watermark information is represented by a random sequence with a much larger length. The detection of a multidimensional watermark in a image is an inverse process. Multiple watermarks can be contained in the same image simultaneously. Using spread spectrum signals, the different watermarks are mutually independent. Multidimensional watermarking in the low to mid-band of discrete cosine transform coefficients improves watermark robustness.
