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Title: Parallel techniques for real-time simulation of videophone image compression algorithms
Author: Elliott, John A.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1992
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Until recently, videophony and videoconferencing have not been commercially successful due to the lack of standards in the image compression algorithms employed. In 1990, the CCITT released a draft of such an algorithm for videophony, known as recommendation H.261. This algorithm took several years to develop, and already several superior algorithms are known. Tools are required to aid the development stage of algorithm design. The commercial success of videophones relies upon standard algorithms and the availability of a ubiquitous digital switched network. The latter has been provided in the form of the CCITT ISDN standard. This project investigates parallel techniques for the real-time simulation of videophone image compression algorithms. The simulations are flexible in the sense that the algorithm being simulated can be changed with little effort. Also, they provide a high degree of algorithm visualisation - i.e. video output from any of the algorithm can be easily viewed. In this thesis a survey of past and present videophone image compression algorithms is presented and the H.261 algorithm is described in detail. The complexity of current algorithms dictates that they cannot be simulated in real-time using conventional sequential computers. Affordable supercomputer power is now available in the form of MIMD distributed memory parallel computers. Such machines can be used to develop complex image processing algorithms in software. The use of parallel computers is in its infancy. It is not clear how the processor networks should be interconnected, what languages should be used, how processes should be mapped to processors and how communications should be managed. The first simulations presented are written in occam with a topology independent routing harness, Tiny, and run on a transputer-based Meiko Computing Surface. 'Compact graph' process network topologies are employed to reduce communications overheads. These simulations are compared with related work. In so doing, various topologies are analysed using meaasures from graph theory.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available