9 January 1998 Mobile videophone systems for radio speech channels
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A suite of bandwidth efficient image codecs are presented for the use in second-generation wireless systems, such as the American IS-54 and IS-95 systems, the Pan-European GSM system and the Japanese digital cellular system. The proposed codecs are configured to operate at 9.6K bits per second and are suitable for Quarter Common Intermediate Format videophone sequences, scanned at 10 frames per second. The new image codecs employ the orthonormal wavelet transform to decompose the displaced frame difference data for each frame, into four frequency subbands. The wavelet coefficients within the frequency subbands are then encoded using vector quantization. Comparison measures are undertaken for the two-stage pairwise nearest neighbor (PNN) algorithm and the designs are rated upon their ability to coherently reconstruct an efficient codebook from a training sequence of vector coefficients. It was found that the two- stage PNN algorithm constitutes a valuable compromise in terms of computational complexity with only negligible performance loss. When the codecs were configured to operate at 9.6Kpbs, the average peak signal to noise ratio of the two stage PNN and the adaptive algorithms were in excess of 28kB and 30dB respectively.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Lee David Scargall, Lee David Scargall, Satnam Singh Dlay, Satnam Singh Dlay, } "Mobile videophone systems for radio speech channels", Proc. SPIE 3309, Visual Communications and Image Processing '98, (9 January 1998); doi: 10.1117/12.298326; https://doi.org/10.1117/12.298326

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