A multiplicative autoregressive model is used in a lossless predictive image coding scheme. The use of vector quantisation (VQ) for compression of the model coefficients leads to an improved compression ratio. Both image adaptive and universal codebooks are considered. A comparative analysis of the new coder is presented through simulation results.

Vector quantisation is a widely used technique in low-bit rate coding of speech and image data, but is highly sensitive to noise in the transmission channel. If the reference vector recalled by a corrupted index di ers greatly from the intended reference vector, image quality can be degraded quite dramatically. The index assignment (IA) process attempts to re-order the code book so as to minimi...

A new non-predictive video codec for mobile applications is presented. The scheme omits the prediction step in the temporal axis and increases robustness of its transmission in the mobile channel. The same subbands from each frame in the group of frames (GOP) are joined together to exploit their spatial-temporal redundancies. The significant vectors of the joined subbands within the GOP are qua...

In this paper we investigate an alternative approach to the design of low-bit rate (LBR) quantisation. This approach incorporates phonetic information into the structure of Line Spectral Frequency (LSF) codebooks. In prior work vector quantisation (VQ) has been used to quantise stochastic processes. Speech signals can, however, be described in terms of phonetic segments and linguistic rules. A ...

This paper uses transform coding for compressing feature vectors in distributed speech recognition applications. Feature vectors are first grouped together into non-overlapping blocks and a transformation applied. A non-uniform allocation of bits to the elements of the resultant matrix is based on their relative information content. Analysis of the amplitude distribution of these elements indic...

The use of motion compensation (both forward and bidirectional) allied with transform−quantisation based coding of the residual predicted error has been ubiquitous in video coding standards. The most recent standard, H.264/AVC, maintains this paradigm, introducing even more efficient tools to determine and compress predicted residue information. In this paper we investigate the effects of elimi...

In this paper, we investigate the use of the Gaussian mixture model-based block quantiser for coding line spectral frequencies that uses multiple frames and mean squared error as the quantiser selection criterion. As a viable alternative to vector quantisers, the GMM-based block quantiser encompasses both low computational and memory requirements as well as bitrate scalability. Jointly quantisi...

Most current image and video coding standards use variable length codes to achieve compression, which renders the compressed bitstream very sensitive to channel errors. In this paper, image and video coders based on Pyramid Vector Quantisation (PVQ) and using only fixed length codes are proposed. Still image coders using PVQ in conjunction with DCT and wavelet techniques are described and their...