Thesis-1980-Wong.pdf (6.25 MB)
Adaptive transform coding of viewphone signals
thesis
posted on 2013-06-13, 13:12 authored by Wai-Choong WongThe initial phase of the research programme involves the design,
development and construction of a reliable and versatile Video
Acquisition and Display System (VADS) to provide a means of
subjective evaluation of the results of computer simulations.
An orthogonal transformation generates a set of uncorrelated
coefficients and has, in addition, an energy compaction property
which leads to more efficient coding of the source data. As an
introduction to its application, its use in the detection and
correction of transmission errors is considered. Simulations are
performed on two-dimensional Gauss-Markov sequences. One-dimensional
Hadamard transformation is performed in the horizontal direction
and the vertical correlation of the simulated data is exploited to
achieve partial error detection and correction.
Viewphone signals, particularly those derived from head and shoulder
scenes, possess much spatial and temporal redundancy which may be
significantly reduced at the expense of a slight, but subjectively
tolerable, degree of degregation in picture quality. The discrete
Cosine transform offers a corriparatively fast and efficient
transformation for achieving this objective, and is used extensively
here, in conjunction with various adaptive algorithms which select
and code the transform coefficients for transmission on the basis
of the statistical and local content of the data. Initially, twodimensional
adaptive techniques are employed followed by an extension
of the ideas developed to the time domain. It is demonstrated that
a marked reduction in the signal transmission rate can be achieved
by this method.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Publisher
© W.C. WongPublication date
1980Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.291872Language
- en