Год выпуска: 2011 Автор: Alison Shortt Издательство: LAP Lambert Academic Publishing Страниц: 252 ISBN: 9783846517673
Описание
The white-noise appearance of digital holograms has led researchers to exclusively employ uniform quantisation as a quantisation compression technique. During my research, I designed novel, and adapted conventional, iterative and non-iterative lossy nonuniform quantisation techniques, and completed the compression process by subsequently applying lossless coding. To quantify performance I combined an RMS metric computed in reconstruction space and compression ratio computed in digital hologram space. I show how iterative techniques (k-means, Kohonen competitive neural network, Kohonen self-organising map, and annealed Hopfield neural network) successfully exploit correlations between real and imaginary components of the digital holograms. Non-iterative techniques (companding, histogram quantisation, optimal quantisation, and wavelets) combine a uniform quantisation grid with nonuniform transformations of the grid and hologram data to trade reconstruction quality for speed. ...
