1Real-Time Digital Watermarking System for Audio Signals Using Perceptual Masking

Recent development in the field of digital media raises the issue of copyright protection. Digital watermarking offers a solution to copyright violation problems. The watermark is a signature, embedded within the data of the original signal, which in addition to being inaudible to the human ear, should also be statistically undetectable, and resistant to any attempts to remove it. In addition, the watermark should be able to resolve multiple ownership claims (known as the deadlock problem), which is achieved by using the original signal (i.e., the unsigned signal) in the signature detection process. In order to meet the above demands, a frequency-masking scheme using a psycho-acoustic model is used to ensure a maximal, yet inaudible, additive signature. The algorithm description is as follows: The audio signal is divided into segments. For each segment a local key is calculated and summed-up with an owners key (independent of the segment) to initiate a pseudo-random noise sequence for the segment. The noise is colored by a filter, which is calculated according to the psycho-acoustic model. The original signal is watermarked by adding the colored noise to it. The project described hereafter contains MatlabTM simulation, a GUI C++ application (insertion & detection) and a real-time embedding scheme on the Texas Instrument