Video Transport System Research Articles

Development of a Broadband Telemedical Network Based on Internet Protocol in the Asia-Pacific Region

To promote the exchange of knowledge and standardization of medical procedures and medical systems in the Asia-Pacific region, we established a medical network with high-quality moving images over broadband Internet lines in February 2003. Real-time teleconferences and live demonstrations with medical-quality videos, broadcast via the Digital Video Transport System, have been used to teach surgical techniques and other medical procedures across national borders. The Asia-Pacific Advanced Network (APAN) committee in August 2005 formally approved our proposal to establish a medical working group within APAN. The network was expanded by the launch of the Trans-Eurasia Information Network 2 in 2006. By the end of 2006, we had conducted 82 events, in 10 countries in the Asia-Pacific region. The multi-station event has increased every year. There have been no serious transmission problems or ethical conflicts so far. With these experiences and current achievements, we hope to extend this advanced network system to the entire Asia-Pacific. This system is a promising and very useful tool for the standardization of medical system and procedures across national borders. Drawing upon these experiences and current achievements, we hope to extend this advanced network system to the entire Asia-Pacific region.

A real-time video transport system for the best-effort Internet

It is a challenging problem to design an efficient real-time video transport system for the present best-effort Internet because of the strict bandwidth, loss and time constraints and the lack of quality of service (QoS) guarantees from the present IP networks. This paper presents an end-to-end system architecture based on the MPEG-4 Delivery Multimedia Integration Framework (DMIF) for transporting real-time live video over the Internet. The key features of the system include: (1) MPEG-4 DMIF-based terminal architecture; (2) combination of an end-to-end feedback control mechanism and a rate-adaptive encoding algorithm for the best use of the Internet; (3) a robust and efficient packetization scheme for the MPEG-4 bit-stream by using the resynchronization marker approach specified in the MPEG-4 standard; and (4) efficient error control algorithms adopted at the end systems for visual quality enhancement. Simulation and test results using the actual Internet showed that our system is capable of utilizing the available network resource and achieve good perceptual quality at the application level.

Development of International Medical Teleconference System Using Advanced Research Network and Digital Video Transport System(DVTS)

Objective: The purpose of this study is to develop telesurgical conference system by establishing a gigabit broad-banded network between hospitals in Korea and Japan using Digital Video Transport System(DVTS) on internet protocol, and to audit performance of this system through questionnaire study. Methods: The Korea Advanced Research Network(Korean side), the Fukuoka Gigabit Highway(Japanese side), and the Korea-Japan Cable Network(international line)were used for assuring a high speed network connectivity. DVTS streaming was propagated with 30 M bps bandwidth for two channels on IPv4 network. Network security was built with virtual private network solution to guarantee protecting patient's privacy. Technological performance and satisfaction of users were evaluated following the events. Results: The teleconference sessions and live surgery transmission with DVTS on Internet protocol using advanced research network were performed successfully. Bandwidth of 60 Mbps for two-line transmission was maintained throughout the conference. The quality of the transmitted pictures had no frame loss with the rate of 30 frames per second. The sound was also clear and the time delay was less than 0.3 sec. Effectiveness of telesurgical conference using advanced network was felt beneficial for 94% of the attendants in questionnaire study. Conclusion: Establishing an international telesurgical conference system with high quality digital video transmission over internet protocol using international gigabit network was performed successfully. With the improvement of network engineering, this system is expected to contribute penetration of medical skills and knowledge through network infrastructure.

超高品質・映像音響技術の構築(マルチメディア通信とQoS, VoIP, ストリーミング, 一般)

超高品質・映像音響技術の構築(マルチメディア通信とQoS, VoIP, ストリーミング, 一般)

Stimulated Raman scattering-induced baseband video distortion due to 1.65-μm OTDR online monitoring in 1.55-μm AM-VSB CATV system

We investigated the online monitoring of a 1.55-μm amplitude-modulation vestigial-sideband CATV video transport system using a 1.65-μm optical time-domain reflectometer (OTDR). The baseband video-picture distortion resulting from the stimulated Raman scattering interaction between the AM video signals and the OTDR pulses in the single-mode fiber link is observed and analyzed.

Fundamental nonlinear distortions in analog links with fiber amplifiers

We analyzes the second-order distortion in a modulated laser-based AM subcarrier multiplexed (AM-SCM) video transport system using fiber amplifiers for power boosting. All three of the involved system elements: the laser, the fiber amplifier, and the transmission fiber, contribute to the system distortion. The laser distortion originates from the internal photon-electron interaction, whereas the fiber amplifier and dispersive distortion are directly related to the intrinsic frequency chirping of the modulated laser. From the distortion magnitude and phase analysis, the author finds that under most situations the distortions have an electronic counterpart and can be electronically compensated. In addition, the system distortion can be minimized with a combination of critically chosen elements that have minimum or counteracting distortion mechanisms. Optically amplified AM-SCM systems can thus be engineered to perform well within the stringent distortion requirements for both 1.3- and 1.55-μm wavelength ranges.

MPEG++: A robust compression and transport system for digital HDTV

This paper provides a technical overview of MPEG++, a robust video compression and transport system for digital HDTV. MPEG++ forms the basis of ‘Advanced Digital Television’ (ADTV), the all-digital terrestrial simulcast system currently under development by the Advanced Television Research Consortium (ATRC). ADTV incorporates an efficient MPEG-compatible compression algorithm at its central core, with application-specific data prioritization and transport features added as separable layers. The compression process is based on a 1440×960 (1050-line 2: 1 interlaced) HDTV format, producing a selectable bit-rate in the region of 15–20 Mbit/s. The data priorization layer of MPEG++ achieves robust delivery over an appropriate two-tier modem by separating compressed video data into high- and standard-priority bitstreams with appropriate bit-rates. This priorized data is then formatted into fixed length ‘cells’ (packets) with appropriate data-link level and service-specific adaptation level headers, designed to provide capabilities such as flexible service multiplexing, priority handling, efficient cell packing, error detection and graceful recovery from errors. An outline of each of the above MPEG++ elements (i.e., compression, prioritization and transport) is given, and is followed by a description of a software model for the system. Simulation model based performance results which illustrate MPEG++ image quality and robustness are briefly reported.

Second-order distortion and electronic compensation in analog links containing fiber amplifiers

A detailed, wide-frequency-range analysis of the second-order distortions in optically amplified subcarrier-multiplexed lightwave video transport systems is presented. It is found that the three major system distortions are from the DFB laser's intrinsic dynamic nonlinearity, the fiber amplifier's nonuniform gain profile, and the fiber's chromatic dispersion. A generic electronic circuit is proposed to compensate the distortions from all three mechanisms simultaneously. A low-distortion, amplified, 1.55- mu m system in which the fiber amplifier and dispersive distortions are suppressed using the proposed circuitry is discussed. >