Multiresolution Source Coding Research Articles

Universal multiresolution source codes

A multiresolution source code is a single code giving an embedded source description that can be read at a variety of rates and thereby yields reproductions at a variety of resolutions. The resolution of a source reproduction here refers to the accuracy with which it approximates the original source. Thus, a reproduction with low distortion is a "high-resolution" reproduction while a reproduction with high distortion is a "low-resolution" reproduction. This paper treats the generalization of universal lossy source coding from single-resolution source codes to multiresolution source codes. Results described in this work include new definitions for weakly minimax universal, strongly minimax universal, and weighted universal sequences of fixed- and variable-rate multiresolution source codes that extend the corresponding notions from lossless coding and (single-resolution) quantization to multiresolution quantizers. A variety of universal multiresolution source coding results follow, including necessary and sufficient conditions for the existence of universal multiresolution codes, rate of convergence bounds for universal multiresolution coding performance to the theoretical bound, and a new multiresolution approach to two-stage universal source coding.

Advanced television systems for terrestrial broadcasting: Some problems and some proposed solutions

The first part of this paper discusses the requirements that must be met by a new television broadcasting system to maximize its acceptability to the various stakeholders, including broadcasters, equipment manufacturers, program producers, regulatory authorities, and viewers. The most important performance factors are efficient use of over-the-air spectrum, coverage versus quality, cost, interoperability, and the existence of a practical transition scenario. It is concluded that all receivers need not have the same peformance, and that low-cost receivers must be available for noncritical locations in the home. If this variation in price and performance is made possible by appropriate system design, then interoperability is facilitated and nondisruptive improvement over time is made possible, as desired by the Federal Communications Commission. In the second part of the paper, techniques that may permit meeting these requirements are discussed. These include joint multiresolution source and channel coding, multicarrier modulation, and hybrid analog/digital coding and transmission. The analog transform coefficients are subjected to spread-spectrum processing, and coded orthogonal frequency-division multiplex (COFDM) is applied to the complex hybrid symbols to be transmitted through the channel. Various methods of equalization and of improving noise, interference, and multipath rejection are compared. Finally, an example is given of a system that meets the various requirements by making use of a number of the techniques discussed. The system provides extended coverage, albeit at lower quality than currently proposed all-digital systems, and equal or higher quality than such systems in much of their service area. It also features self-optimization at each receiver depending on signal quality and receiver characteristics, and facilitates the design of receivers of lower cost and performance for less-critical applications.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A unified approach to moving-image coding for most media and most applications

Developments in picture coding for broadcast television, multimedia workstations, and other applications, have led to a movement to develop source- and channel-coding methods that would simplify interoperability between different formats. Interoperability considerations include not only equipment cost and complexity, but also the image quality achieved when pictures originating in one application are used in another. In this paper, we attempt to set forth the requirements for such universal coding systems and to explore new and old ideas that can be applied to their design. Among the potentially useful techniques are multiresolution source coding, channel coders that permit various decoders to use more or less of the transmitted information, and special modulation/transmission methods, such as orthogonal frequency-division multiplex and single-frequency networks, which are designed to deal with the particular problems of terrestrial broadcasting. One of the main messages that we hope to deliver in this paper is that further progress in this field requires at least as much attention to channel coding as has heretofore been applied to source coding. This is as true for computer-related applications as it is to broadcasting; it is highly likely that the computer of the future will have an antenna.

Multiresolution broadcast for digital HDTV using joint source/channel coding

The use of multiresolution (MR) joint source-channel coding in the context of digital terrestrial broadcasting of high-definition television (HDTV) is shown to be an efficient alternative to single-resolution techniques, which suffer from a sharp threshold effect in the fringes of the broadcast area. It is shown how matched multiresolution source and channel coding can provide a stepwise graceful degradation and improve the behavior, in terms of coverage and robustness of the transmission scheme, over systems not specifically designed for broadcast situations. The alternative available for multiresolution transmission through embedded modulation and error correction codes are examined. It is also shown how multiresolution trellis-coded modulation (TCM) can be used to increase coverage range. Coding results and simulations of noisy transmission are presented, and tradeoffs are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Combined multiresolution source coding and modulation for digital broadcast of HDTV

A practical end-to-end all-digital multiresolution system is demonstrated that employs joint source-channel coding and modulation in order to achieve efficient broadcast of digital HDTV. The threshold effect plaguing single resolution systems is softened by a stepwise graceful degradation. This can be used to increase the coverage and robustness of the digital broadcast system. This approach is seen as an alternative to traditional single resolution digital transmission systems which are not designed for broadcast situations, and which suffer from the threshold effect. This paper highlights the benefits of using an embedded multiresolution modulation constellation over a modulation scheme that resorts to time or frequency multiplexing of the broadcast resolutions. Besides showing coding results and simulations of transmission effects, the paper discusses the trade-offs between low and high resolution coverage.

Multiresolution coding techniques for digital television: A review

Multiresolution decompositions for video coding are reviewed. Both nonrecursive and recursive coding schemes are considered. In nonrecursive schemes, it is shown that pyramid structures have certain advantages over subband or wavelet techniques, and a specific spatiotemporal pyramid coding of HDTV is discussed in some detail. It is shown that recursive, DPCM like schemes will incur a slight loss of optimality due to a restricted form of prediction if multiresolution decomposition with compatible decoding is required. Compatibility and transmission issues are also discussed. Multiresolution transmission for digital broadcast TV is introduced. This, when combined with multiresolution source coding, achieves spectrum efficiency, robustness and graceful degradation under channel impairments.