Georgia Tech Research Corporation

Other

Mark J Smith

Faouzi Kossentini

E Bryan George

Alen Docef

A video coding system and method enable communication of a noisy video signal over communications channels, such as low capacity channels (e.g., telephone lines), by efficiently decomposing the video signal into an underlying structure component and a texture component using subband decomposition. Because much of a texture component is random noise, the texture component lends itself to temporal decimation. This predicament results in a texture frame being encoded and transmitted once every D.sub.t frames and allows texture frames to be sent at a lower rate than underlying structure frames. Because the underlying structure component contains most of the information related to structure, it is decimated in the spatial domain, which allows for maximum data transfer. The texture component and underlying structure component are then coded for transmission over the communications channel, such as a low capacity conventional telephone line, using a method which exploits the characteristic noise and the quasiperiodic nature of the signal.

Video coding system and method for noisy signals

A subband coder with jointly optimized multistage residual quantizers and entropy coders for image coding which allows the subband coder to exploit both linear and non-linear dependencies that may exist within and across the subbands. Both inter- and intra-band dependencies are simultaneously exploited via jointly optimizing the subband coders and entropy coders in an entropy constrained optimization framework involving rate, distortion and complexity. The multistage quantization structure and the effectiveness of the statistical modeling algorithm results in an attractive balance among reproduction quality, rate and complexity.

Jointly optimized subband coding system and method

A method and apparatus for the automatic analysis, synthesis and modification of audio signals, based on an overlap-add sinusoidal model, is disclosed. Automatic analysis of amplitude, frequency and phase parameters of the model is achieved using an analysis-by-synthesis procedure which incorporates successive approximation, yielding synthetic waveforms which are very good approximations to the original waveforms and are perceptually identical to the original sounds. A generalized overlap-add sinusoidal model is introduced which can modify audio signals without objectionable artifacts. In addition, a new approach to pitch-scale modification allows for the use of arbitrary spectral envelope estimates and addresses the problems of high-frequency loss and noise amplification encountered with prior art methods. The overlap-add synthesis method provides the ability to synthesize sounds with computational efficiency rivaling that of synthesis using the discrete short-time Fourier transform (DSTFT) while eliminating the modification artifacts associated with that method.

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Mark J Smith