In this paper, intelligent compression techniques to allow transmission of text and image data over low bit rate channels are proposed. For text, a compression technique for English language text is presented. Compression is carried out by deleting characters that are not necessary for comprehension by a human reader. Decompression is carried out on a sentence by sentence basis using a database...

In this thesis, a parametric audio coding system for very low bit rates is presented. It is based on a generalized framework that combines different source models into a hybrid model and thereby permits flexible utilization of a broad range of source and perceptual models. The developed parametric audio coding system allows efficient coding of arbitrary audio signals at bit rates in the range o...

This paper treats the topic of how to eeciently represent facial textures, for model based coding of human face images. The scheme is based on the Karhunen-Lo eve transform and involves an elaborate normalization process that enhances PSNR with around 0.5 dB compared to normalization with scaling, translation and rotation. It also seems to augment the perceived visual quality. Furthermore, a bl...

The concept of high-order motion compensation is introduced. It is argued that in hybrid video coding, motion-compensated prediction has to be viewed as a source coding problem with a delity criterion. Based on our considerations, various high-order motion compensation approaches are presented that achieve signi-cantly improved video coding results. The designed motion-compensated predictors ac...

Audio coding at very low bit rates requires very efficient evaluation of characteristics of the signal sources and of perceptual properties of the human ear. An overview of models for the signal source employed in different coding schemes is given. Some of the basic concepts for perceptual quantization and coding of model parameters are shown, including approaches for scaleability with respect ...

We developed a very low bit rate watercolor-like video form, which is constructed with a bi-level Y luminance component and a number of UV chrominance combinations. The bi-level Ycomponent outlines the features of an image and the UVcombinations describe the basic color information of the image. The UV combinations are dynamically chosen during encoding. The resultant video looks better than bi...

In this paper we present two methods of enhancing the eigen face approach for the compression of images of human faces. In earlier work, a series of image basis functions (eigen faces) is created using the KarhunenLoeve transform on a large set of face images (the training set). The image to be encoded can then be approximated by a linear combination of these basis functions. We propose a rever...

| This paper treats the topic of how to eeciently represent facial textures, for model based coding of human face images. The scheme is based on the Karhunen-Lo eve transform and involves an elaborate normalization process that enhances PSNR with around 0.5 dB compared to normalization with scaling, translation and rotation. It also seems to augment the perceived visual quality. Furthermore , a...

In this paper, two new hybrid algorithms are proposed for decoding Low Density Parity Check (LDPC) codes. Original version of the proposed algorithms named Search Based Weighted Multi Bit Flipping (SWMBF). The main idea of these algorithms is flipping variable multi bits in each iteration, change in which leads to the syndrome vector with least hamming weight. To achieve this, the proposed algo...

This paper investigates Waveform Interpolation (WI) applied low bit rate wideband speech coding. An analysis of the evolutionary behaviour of wideband Characteristic Waveforms (CWs) shows that direct application of the classical WI algorithm may not be appropriate for wideband speech. We propose a modification whereby CW quantisation is performed using classical WI decomposition for the low fre...