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.

Quality of television pictures

MPEG-2 test stream for evaluation the static picture quality of digital television (DTV) should meet both good picture quality and stable bit rate. In this paper, we present a method for generating a high quality test stream to evaluate the static picture quality in DTV receiver. The proposed method is suitable for encoding the static test pattern, such as multiburst and crosshatch, and is based on user-defined quantization and adaptive zero stuffing algorithm. The user-defined quantization is suitable for minimizing the quantization error, which is the reason of degradation of picture quality, and the adaptive zero stuffing algorithm is used to solve the overflow of video buffer verifier (VBV) buffer while encoding process by MPEG-2 encoder. Experimental results show that the average PSNR and the bit rate of the proposed method have more efficient and stable than those of the conventional.

Over the past several years we have investigated viewer response to temporal fluctuations in the quality of digital television pictures, which occur when video is coded into relatively low bit rates. Three phenomena of interest have been identified: (1) a forgiveness effect, (2) a recency effect, and (3) a negative-peak (duration-neglect); these are described and discussed in the paper. In collaboration with our partners in European projects MOSAIC and TAPESTRIES, we have developed a three-stage method of measuring time-variant quality, which has been accepted by the ITU-R. The first stage is a Single Stimulus Continuous Quality Evaluation (SSCQE) of instantaneous quality; the second a calibration stage to link SSCQE with conventional DSCQS, and the third stage a numerical procedure for relating continuous and overall quality. Some of the factors we have identified as being important in producing good overall quality judgements have relevance to the design of optimal coding strategies for digital television.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This paper describes a scalable MPEG-2 bit-rate transcoder that scales from low complexity, resulting in moderate picture quality, to high complexity with much better quality. The algorithm presents a very fine grain scalability in terms of complexity, making this solution especially suitable for software implementations, in order to benefit from the available resources to increase picture quality. Picture quality degrades gracefully when the complexity of the algorithm is decreased.

Digital television was introduced to the Belgian market in the summer of 2005. Compared to other European countries, this was fairly late. In the end of 2009, we have reached the 50% penetration threshold of digital television households. Considering previous research into user adoption of digital television in Belgium, it can be stated that the stage of adoption by the 'majority segments' has been reached. However, the research carried out shows that most people just enjoy the improved picture quality of digital television but have not changed their viewing habits and have, therefore, not adopted the use of interactive applications such as video on demand, time-shifted viewing, voting, e-mail, etc. The user adoption rate of 50% for DTV therefore does not imply a 50% use diffusion rate of interactive services.The most important challenge for the future will be to convince the remaining 50% of analogue viewers to make the switch to DTV. A review of the literature on the adoption and diffusion processes of technologies shows that these late adopters (laggards and late majority) base their decision on the behavior of peers who have already acquired the technology. As they are the least innovative market segment, they will require some compelling arguments to adopt iDTV. Compelling selling arguments for this technology could be related to the added value of interactive services which are currently not being used to their full potential by iDTV subscribers.This paper discusses two important research questions based on quantitative empirical data. Firstly, how can the 50% remaining analogue viewers be convinced to switch to iDTV? Secondly, how can the gap between the 50% of user adoption of iDTV and the lack of use diffusion of interactive services be bridged?

Performance analysis of cell discarding techniques for best effort video communications over ATM networks

This paper describes a perceptual measure for still image compression system. Considering the fact that the conventional PSNR cannot sufficiently reflect the result of subjective assessment, other quality measure have been considered to design the variable bit-rate coders. Indeed, there is a growing interest for perceptual quality measure. Some works have been carried out in the field of still picture quality evaluation while trying to introduce some properties of the human visual system. In the recent literature there are roughly three properties that are identified as being useful. The best known, and generally most widely used properly, is the modulation transfer function of the human visual system. The other tow properties can be described as luminance masking and texture masking. A large number of image quality measures of this kind have been developed, with different degrees of success. In previous works, we provided a rigorous evaluation of metrics which take into account artifacts generated by compression method like JPEG. The results show that these metrics are highly correlated with the subjective quality grading but also depend on the complexity of the images under study. Then, we propose a new perceptual metric for still image compression based on multiresolution decomposition. It allows characterize image texture, better takes into account masking effect and don't depend on compression method.

Transistorised amplifiers for video transmission over coaxial cables incorporate power units with d.c.-d.c. convertors that produce an aggregate effect similar to that of band-limited random noise at low frequency. The subjective effect of such noise, centred at 3.2 and at 7.5kHz, has been investigated. Tests were also made with sinewave noise at the frequencies giving the worst effect in the regions of 1 and 3.2kHz and 1 and 3.2MHz. Results are summarised in the form of signal/noise ratios for a series of ‘imp’ mark points that has recently been introduced.

Fine-granularity-scalability (FGS) has recently been adopted by the MPEG-4 standard for the efficient and flexible distribution of multimedia over the Internet. The FGS framework is able to perform spatio-temporal-SNR tradeoffs in real-time at transmission or (post-) processing time, depending upon the available bit-rate, sequence characteristics, priority, user preferences or receiver resources, and not at encoding time. This paper investigates the usage of FGS for robust video transmission over wireless networks. To cope with the detrimental channel conditions, we introduce a novel joint source-channel coding scheme that combines FGS and adaptive modulation. Two schemes are presented, one uses hierarchical modulation and FGS and the other uses time division multiplexing and FGS. Both schemes are shown by computer simulation to maintain a stable video quality over a variety of multipath dynamic Rayleigh fading channels. The proposed adaptive modulated FGS algorithms provide a graceful degradation and improvement in picture quality as the channel conditions vary.

Increasing interest in the transmission of audiovisual applications over best-effort networks (i.e., IP and ATM ABR, and UBR services) and efficient video-aware congestion control techniques have to be designed in order to improve the video quality in the presence of cell loss. This paper presents a new slice-based discard scheme to be used with Guaranteed Frame Rate service (formerly UBR+). The scheme adaptively and selectively adjusts discard levels to the switch's buffer occupancy, video cell payload types, and Forward Error Correction Drop Tolerance. To improve its performance, we introduce a distributed multiagent system that provides a self-regulating network control management by means of automatic adjustment of congestion control parameters. The control agents are distributed in the network and operate on a local scope referred to as a “domain” consisting of two adjacent ATM switches. The aim of the overall Intelligent Quality-of-Service (QoS) control framework is twofold. First, to ensure graceful picture quality degradation by minimizing the cell loss probability for critical video data while guaranteeing a bounded cell transfer delay. Second, to optimize the network effective throughput by reducing the transmission of “nonuseful” data. Performance evaluations show significant improvement over traditional approaches.

Power Line Interference and Assessment of Television Picture Quality

For critical evaluation of television picture quality, all factors affecting the perception of colors and brightness should be closely controlled. CTP-2 specifies the chromaticity and luminance of reference white, surround light and other general viewing conditions.

Set-lighting in making motion pictures for color television is described. It was found that optimum television picture quality was obtained when the subject-lighting contrast was reduced to correspond more nearly with the range of brightness which can be reproduced over a color-television system.

The ideal objective of combining therapeutic pictures is converging of the numerous pictures acquired from multimodalities into a solitary picture for prevalent sickness analysis. A tale calculation for skillful melding of multimodal restorative pictures is proposed in this paper. For combining of restorative pictures, Undecimated Discrete Wavelet Transform domain (UDWT) and Intuitionistic fuzzy sets are used. Dominant of the available fusion techniques are working in light of Discrete Wavelet Transform (DWT). A slight obscuring is seen when DWT is utilized for image fusion. By using UDWT, this blurring is significantly reduced. There is no decimation process in UDWT. Henceforth, wavelet coefficients are processed for every area permitting better identification of prevailing highlights. It is a non-orthogonal multi-resolution decomposition. In the UDWT domain, the low recurrence sub-groups are combined by the Maximum Selection Rule and the high recurrence sub-groups are intertwined by the Modified Spatial Frequency (MSF). Recreations are carried on different therapeutic pictures and diverged from strategies exist up until now. Predominance of the proposed technique is introduced and supported. Combined picture quality is affirmed with number of value measurements i.e., Entropy (H), Spatial Frequency (SF), Peak Signal to Noise Ratio (PSNR), Mean Square Error (MSE), Edge-based image fusion metric (QAB/F), Correlation Coefficient (CC), Quality Index (QI) and Structural Similarity (SSIM).