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vResearch Article Robust Speech Watermarking Procedure in the Time-Frequency Domain | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2008 Article ID 519206 9 pages doi 2008 519206 Research Article Robust Speech Watermarking Procedure in the Time-Frequency Domain Srdjan Stankovic Irena Orovic and Nikola Zaric Electrical Engineering Department University of Montenegro 81000 Podgorica Montenegro Correspondence should be addressed to Irena Orovic irenao@ Received 18 January 2008 Accepted 16 April 2008 Recommended by Gloria Menegaz An approach to speech watermarking based on the time-frequency signal analysis is proposed. As a time-frequency representation suitable for speech analysis the S-method is used. The time-frequency characteristics of watermark are modeled by using speech components in the selected region. The modeling procedure is based on the concept of time-varying filtering. A detector form that includes cross-terms in the Wigner distribution is proposed. Theoretical considerations are illustrated by the examples. Efficiency of the proposed procedure has been tested for several signals and under various attacks. Copyright 2008 Srdjan Stankovic et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION Digital watermarking has been developed as an effective solution for multimedia data protection. Watermarking usually assumes embedding of secret signal that should be robust and imperceptible within the host data. Also reliable watermark detection must be provided. A number of proposed watermarking techniques refer to the speech and audio signals 1 . Some of them are based on spreadspectrum method 2-4 while the others are related to the time-scale method 5 6 or fragile content features combined with robust watermarking 7 . The existing watermarking techniques are mainly based on either the time or frequency domain. .