Audio Watermarking System Using EMD with Psyehoacoustic Model
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Date
2013
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Abstract
A new adaptive audio watermarking algorithm
based on empirical mode decomposition (EMD) with human
aiiditoi7 and psychoacoustic model is used in this I'esearch. The
audio signal is divided into frames and each one is decomposed
adaptively, by EMD, into intrinsic oscillatory components called
Intrinsic Mode Functions (IMFs). The watermark and the
synchronization codes are embedded into the extrema of the last
IMF, a low frequency mode stable under different attaclis and
presei'ving audio |)erceptual quality of the host signal. The data
embedding rate of tbe EMD algorithm is 46.9-50.3 b/s. Relying
on exhaustive simulations, show the robustness of the hidden
watermark for additive noise, MP3 compression, re-quantization,
fdtering, cropping and resampling. Empirical Mode
Decomposition (EMD) has been introduced for analyzing nonstationai7
signals derived or not from linear systems in totally
adaptive way. A major advantage of EMD relies on no a priori
choice of fdtei'S or basis functions. EMD is fully data-driven
metbod that reciii-sively breaks down any signal into a reduced
number of zero-mean with symmetric envelo|)es AM-FM
components called Intrinsic Mode Functions (IMFs). The
decomposition starts from finer scales to coaiser ones.
The psychoacoustic model is basically based on many studies
of human auditory perception. In this research, the watermark in
audio can be embedded and extracted with different techniques.
The psychoacoustic model can be done before embedding the
watermark bit. In the scheme, the additive watermarking
technique is used to embed a unique pseudo- random sequence,
considered as a watermark, into the transformed domain of
audio signal. The watermark strength is properly adjusted based
on weighting factors derived from the proposed psyehoacoustic
models. The results show that at the equivalent quality of the
watermarked audio, judged by tbe human hearing system, the
robustness of the embedded watermark was increased to higher
liercentage, compared to the results obtained from tbe scheme
with non- psyehoacoustic model and the [isyclioacoiistic model.