Audio Watermarking Systems - Design, Implementation and Evaluation of an Echo Hiding Scheme Using Subjective Tests and Common Distortions

Abstract

Today's digital media have made the product (digital content) very flexible and diminished the cost of its distribution. However, it contributes on piracy explosion as digital content can be duplicated and re-distributed at virtually no cost. Watermarking technology appears in order to protect the intellectual property and fight the piracy. It consists on embedding data like copyright labels inside a data source without changing its perceptual quality. In audio domain, watermarking techniques rely on the imperfection of the human auditory system in order to embed data. In this paper, we completed a design based on echo hiding technique and implement it in MATLAB.The main idea of this method is to embed data into an original signal by introducing an echo with the appropriate delay. Subjective listening tests reveal that the watermarks are imperceptible. Fidelity tests show that quantity of distortion imposed by watermarks on a signal is small. Robustness tests against common signal processing reveal good responses. The watermark information is always detectable and recoverable.