Title :
Digital coding of covert audio for monitoring and storage
Author :
Mason, M. ; Sridharan, S. ; Prandolini, R.
Author_Institution :
Sch. of Electr. & Electron. Syst. Eng., Queensland Univ. of Technol., Brisbane, Qld., Australia
Abstract :
This paper offers an overview of the requirements of digital covert audio acquisition (DCAA) and presents a codec that provides both real-time monitoring and efficient on-site storage. The codec incorporates an M-band discrete wavelet transform (DWT) subband decomposition with lattice vector quantisation (LVQ) of the wavelet coefficients to compress high quality covert audio to less then 32 kbps. Both objective quality measures for the monitoring channel and average growth rate of the on-site storage are presented to demonstrate that the proposed codec achieves the requirements of a covert audio acquisition system
Keywords :
audio coding; codecs; digital storage; discrete wavelet transforms; monitoring; signal reconstruction; surveillance; vector quantisation; LVQ; M-band discrete wavelet transform; audio compression; average growth rate; codec; covert audio surveillance; digital coding; digital covert audio acquisition; efficient on-site storage; lattice vector quantisation; law enforcement bodies; monitoring; monitoring channel; objective quality measures; real-time monitoring; signal reconstruction; storage; subband decomposition; wavelet coefficients; Australia; Codecs; Discrete wavelet transforms; Monitoring; Signal processing; Speaker recognition; Speech; Surveillance; Vector quantization; Wavelet coefficients;
Conference_Titel :
Signal Processing and Its Applications, 1999. ISSPA '99. Proceedings of the Fifth International Symposium on
Conference_Location :
Brisbane, Qld.
Print_ISBN :
1-86435-451-8
DOI :
10.1109/ISSPA.1999.818215
