Computer implemented system for audio watermarking

摘要

A computer implemented system for audio watermarking for providing robust and blind audio watermarking. The system comprises a watermark embedding system wherein an audio signal is divided into audio frames, multi-level District Wavelet Transform (DWT) is applied on each frame, followed by Singular Value Decomposition (SVD) and embedding the watermark, further followed by inverse SVD and inverse DWT to get watermarked audio frames which are combined to generate a watermarked audio signal. The system further comprises watermark extracting detection system wherein the watermarked audio signal which may be attacked and/or modified is divided into watermarked audio frames, multilevel DWT is applied on each watermarked audio frame, followed by SVD, extracting the embedded watermarked, correlating the extracted watermark with pre-stored watermarks, calculating Peak to Sidelobe ratio (PSR) from the correlation coefficient arrays and finally comparing each PSR with a threshold to authenticate the embedded watermark.

主权项

1. A computer implemented system for audio watermarking, said system comprising:
a watermark embedding system for embedding a watermark in an audio signal, said watermark embedding system comprising:
a first dividing module adapted to divide an audio signal into a plurality of audio frames, each frame being of pre-determined size and having a pre-determined number of samples of said audio signal;a first transforming module adapted to apply multi-level Discrete Wavelet Transform (DWT) on each frame to generate detailed coefficients and approximation coefficients at each level;a first arranging module adapted to arrange the generated detailed coefficients from all levels of DWT to form a matrix of detailed coefficients;a first decomposing module adapted to apply Singular Vector Decomposition (SVD) on said matrix of detailed coefficients to factor said matrix into at least a diagonal matrix;an embedding module adapted to embed a watermark bit with a scaling factor to a second Eigen value from top left to bottom right of said diagonal matrix to generate a modified diagonal matrix;a second decomposing module adapted to apply inverse SVD on at least said modified diagonal matrix to produce modified detailed coefficients;a second transforming module adapted to apply multi-level inverse DWT on the modified detailed coefficients and the generated approximation coefficients to create a watermarked audio frame; anda combining module adapted to combine each watermarked audio frame sequentially to produce a watermarked audio signal; and a watermark detection system for detecting the watermark from the watermarked audio signal, said watermark detecting system comprising:
a synchronization module adapted to determine a synchronization point in the watermarked audio signal;a second dividing module adapted to divide the watermarked audio signal into a plurality of watermarked audio frames, each watermarked audio frame being of pre-determined size and having a pre-determined number of samples of the watermarked audio signal;a third transforming module adapted to apply multi-level DWT on each watermarked audio frame to generate watermarked detailed coefficients and watermarked approximation coefficients at each level;a second arranging module adapted to arrange the watermarked detailed coefficients from all levels of DWT to form a watermarked matrix of detailed coefficients;a third decomposing module adapted to apply SVD on said watermarked matrix of detailed coefficients to factor said watermarked matrix into at least a watermarked diagonal matrix;a detection module adapted to collect a second Eigen value of said watermarked diagonal matrix and storing the collected second Eigen value in an array;a correlation module adapted to correlate all the collected second Eigen values stored in said array with all watermarks pre-stored in the repository to generate correlated arrays proportionate to the watermarks pre-stored in the repository;a calculation module computes Peak to Sidelobe Ratio (PSR) from each correlation output; anda comparison module adapted to compare each calculated PSR with a pre-determined threshold to authenticate the embedded watermark.