Data compression systems for home-use digital video recording

The authors focus on image data compression techniques for digital recording. Image coding for storage equipment covers a large variety of systems because the applications differ considerably in nature. Video coding systems suitable for digital TV and HDTV recording and digital electronic still picture storage are considered. In addition, attention is paid to picture coding for interactive systems, such as the compact-disc interactive system. The relation between the recording system boundary conditions and the applied coding techniques is outlined. The main emphasis is on picture coding techniques for digital consumer recording     

Model-based coding of videophone images

The requirement for improved picture quality in videophone and videoconference systems operating at low bit-rates has stimulated interest in model-based image coding. Two model-based coding techniques are described which are capable of producing either improved picture quality at bit-rates around 64 kbit/s or acceptable picture quality at bit-rates far lower than 64 kbit/s. The first technique produces facial expressions by using feature code-books; the second technique produces facial expressions by distorting an underlying three-dimensional model. The problems of image analysis and synthesis, which are concomitant in model-based coding, are discussed     

Quality of band-compressed TV services

Some typical digital high-efficiency coding algorithms applied to the different types of digital transmission systems are discussed, and the resultant picture quality degradation is examined. Techniques for bit-rate reduction, which is fundamental to high-efficiency coding, are described, namely interframe prediction and conditional picture replenishment, hybrid coding using the discrete cosine transform, and vector quantization. Pulse-code-modulation noise, coding distortion, and channel coding error are considered. Subjective and objective methods for evaluating coded pictures are described     

Picture Coding

A survey of recent German research in the field of picture coding is presented. The described coding methods are mainly based on extended differential pulse-code modulation (DPCM) techniques. A unified model of a feedback switched quantizer for picture coding is explained. Theoretical results show a 9-dB gain in SNR over that of DPCM. A simple realization is shown. For encoding the 1-MHz videotelephone signals, a two-stage coding system consisting of a two-dimensional DPCM in the first stage and a dot interlaced frame repeating codec in the second stage is described. A DPCM combined with a relevancy detector and runlength coder is used for coding the 5-MHz video signals of a high-resolution videotelephone. A special scanning technique assures compatibility with ordinary videotelephones. Good picture quality is obtained by coding the luminance and chrominance signals of color TV separately with DPCM and switched quantization into a 34 Mbit/s signal.     

模型基图像编码

本文扼要综述模型基图像编码中两类方法(语义基和物体基)的最近成果。此外,还介绍了两种新的可视通信系统(虚拟空间会议电视和电视呈现系统)之构想。     

Feedback-based error control for mobile video transmission

We review feedback-based low bit-rate video coding techniques for robust transmission in mobile multimedia networks. For error control on the source coding level, each decoder has to make provisions for error detection, resynchronization, and error concealment, and we review techniques suitable for that purpose. Further, techniques are discussed for intelligent processing of acknowledgment information by the coding control to adapt the source coder to the channel. We review and compare error tracking, error confinement, and reference picture selection techniques for channel-adaptive source coding. For comparison of these techniques, a system for transmitting low bit-rate video over a wireless channel is presented and the performance is evaluated for a range of transmission conditions. We also show how feedback-based source coding can be employed in conjunction with precompressed video stored on a media server. The techniques discussed are applicable to a wide variety of interframe video schemes, including various video coding standards. Several of the techniques have been incorporated into the H.263 video compression standard, and this standard is used as an example throughout     

Ordering techniques for facsimile coding: A review

This paper presents a review of ordering techniques for efficient digital coding of two-level facsimile signals. Ordering techniques use the two-dimensional correlation present in spatially close picture elements (pels) to change the relative order of transmission of elements in a scan line so as to increase the average length of the runs of consecutive black or white elements in the ordered line. This makes the ordered data more amenable to run-length coding. Several extensions of this basic technique are discussed along with simulation results using the 8 standard CCITT images. Only schemes which allow an exact reproduction of the picture at the receiver are considered. Simulations show that on the average one-dimensional run-length coding requires 445 316 bits/document, whereas, one of the variations of the ordering technique requires 264 632 bits/document. A total of 3 702 720 bits/ document would be required if no compression is attempted. Thus the ordering techniques reduce the number of coded bits by about 41 percent compared to one-dimensional coding, and by about 93 percent compared to uncompressed data.     

Maximum runlength-limited codes with error control capabilities

New methods are presented to protect maximum runlength-limited sequences against random and burst errors and to avoid error propagation. The methods employ parallel conversion techniques and enumerative coding algorithms that transform binary user information into constrained codewords. The new schemes have a low complexity and are very efficient. The approach can be used for modulation coding in recording systems and for synchronization and line coding in communication systems. The schemes enable the usage of high-rate constrained codes, as error control can be provided with similar capabilities as for unconstrained sequences     

Picture coding for videotelephony,television and high-definition television

After a brief introduction explaining the present-day context of picture coding and bitrate reduction techniques for videotelephony, television and high-definition television, the basic principles of bitrate reduction techniques are reviewed. These techniques include spatiotemporal resolution limitation, decorrelative processes and noise weighting. Each of these topics is reviewed and a typical coding algorithm is presented. Adequate entropic codes are discussed. The paper, which is of a tutorial nature, ends with a brief discussion of the impact of future network techniques and of their influence on further research.     

An Interframe Coding System for Video Teleconferencing Signal Transmission at a 1.5 Mbit/s Rate

This paper describes the interframe coding system (TRIDEC 1.5) used for NTSC color television signal transmission at a 1.5 Mbit/s rate. TRIDEC 1.5 is developed with the intention of making video teleconferencing service more economical. The system utilizes the following highly efficient coding techniques: 1) interframe combinational difference coding 2) temporal subsample coding 3) noise reduction 4) demand refreshing to protect against channel errors, which makes periodic forced refreshing unnecessary. In addition, new coding parameter control methods have been devised to prevent buffer memory overflow. The subjective evaluation test results make it clear that the encoded picture quality is good enough for teleconferencing use.     

Picture coding

A critical view is presented of the development of certain picture coding systems. An attempt is made to unify the treatment of these systems by emphasizing the reaction of the observer to the types of alteration introduced into the transmitted signal, on the basis of what is known about vision. For the purpose of casting a number of apparently different techniques into similar forms, the relationship between differential quantizing and PCM is discussed in detail. We conclude that the pre- and post-quantizing filters play a key role in these systems. Optimum choice of such filters is shown to improve both quality and efficiency. Two-dimensional and dual-mode systems are seen to be outgrowths of these considerations. Recent results are described and a method of comparison between systems is proposed.     

The improved gray scale and the coarse-fine PCM systems, two new digital TV bandwidth reduction techniques

Two new digital television bandwidth-reduction techniques are presented with experimental results. Each provides twice the efficiency of a conventional pulse code modulation (PCM) system with similar picture fidelity, and each is simple and feasible for present-day spacecraft Implementation. The Improved Gray Scale PCM system effectively eliminates, by an averaging process, the gray scale contouring effect encountered in low-bit digital TV systems. The Coarse-Fine PCM system is somewhat more complex, but provides a higher fidelity reproduction of the original picture. The basic principles of operation of these two new data-compression techniques are given along with comparative pictorial results.     

Data compression of stereopairs

Two fundamentally different techniques for compressing stereopairs are discussed. The first technique, called disparity-compensated transform-domain predictive coding, attempts to minimize the mean-square error between the original stereopair and the compressed stereopair. The second technique, called mixed-resolution coding, is a psychophysically justified technique that exploits known facts about human stereovision to code stereopairs in a subjectively acceptable manner. A method for assessing the quality of compressed stereopairs is also presented. It involves measuring the ability of an observer to perceive depth in coded stereopairs. It was found that observers generally perceived objects to be further away in compressed stereopairs than they did in originals. It is proved that the rate distortion limit for coding stereopairs cannot in general be achieved by a coder that first codes and decodes the right picture sequence independently of the left picture sequence, and then codes and decodes the left picture sequence given the decoded right picture sequence     

Image segmentation for compression of images and image sequences

Region-based image coding schemes, the so-called second generation techniques, have gained much favour in recent years. For still picture coding, they can increase the compression ratio obtained by transform coding by an order of magnitude, while maintaining adequate image representation. The success of these techniques relies on the ability to describe regions in an image succinctly by their shape and size. The algorithms presented describe methods for segmenting images. Unlike most other region based algorithms, these algorithms incorporate knowledge of the border coding process in deciding how to partition the image. The extension from single image compression to sequential image compression is also considered. A new, efficient segmentation scheme is proposed that exploits temporal redundancies between successive images, and reduces some problems associated with error accumulation in error images     

Coding for Satellite Communication

This paper discusses a number of coding techniques for future satellite communication; they include Reed-Solomon error decoding for message blocks, probabilistic decoding techniques for punctured convolutional codes, and planar Euclidean geometry difference set codes for random multiple access applications. The provision of code concatenation, helical interleaving, and simulation results of new punctured convolutional codes are included. A number of coded satellite systems that demonstrate the usefulness of coding in satellite communications are described.     

Transform picture coding

Picture coding by first dividing the picture into sub-pictures and then performing a linear transformation on each sub-picture cud quantizing and coding the resulting coefficients is introduced from a heuristic point of view. Various transformation, quantization, and coding strategies are discussed. A survey of all known applications of these techniques to monochromatic image coding is presented along with a summary of the dependence of performance on the basic system parameters and some conclusions.     

Extended lapped transforms: properties, applications, and fastalgorithms

The family of lapped orthogonal transforms is extended to include basis functions of arbitrary length. Within this new family, the extended lapped transform (ELT) is introduced, as a generalization of the previously reported modulated lapped transform (MLT). Design techniques and fast algorithms for the ELT are presented, as well as examples that demonstrate the good performance of the ELT in signal coding applications. Therefore, the ELT is a promising substitute for traditional block transforms in transform coding systems, and also a good substitute for less efficient filter banks in subband coding systems