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A computer simulation of wavelet noise reduction in computed tomography
Author(s) -
Harpen Michael D.
Publication year - 1999
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.598654
Subject(s) - noise reduction , noise (video) , filter (signal processing) , wavelet , reconstruction filter , projection (relational algebra) , iterative reconstruction , computer science , variance reduction , reduction (mathematics) , computer vision , algorithm , artificial intelligence , shot noise , mathematics , filter design , image (mathematics) , statistics , monte carlo method , root raised cosine filter , detector , telecommunications , geometry
We describe the use of a graphical mathematical spreadsheet programming environment which can be used to simulate the acquisition and reconstruction processes of an x‐ray computed tomography (CT) machine. The simulation is used to study the effect of photon counting statistics on the noise in the reconstructed image. Finally we describe and evaluate a novel technique for noise reduction using a nonlinear wavelet filter in which the filter thresholds are calculated individually from the “measured” projection data. This filter is shown to compare favorably to threshold filters based on global estimates of noise variance.