Quantification Of Oleoresin In Agarwood By Means Of Micro-Computed Tomography And Digital Image Processing
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Date
2011-05
Authors
Yazid @ Khalid, Khair'iah
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Micro-focus X-ray computed tomography is a powerful non-destructive
scanning technique to study internal micro-structure in wood. In this thesis, the study
contains two parts. The first part involves the reconstruction of an image from CT
projections. An algorithm referred to as XRecon program has been developed to allow
slice reconstruction for parallel beam and fan beam data. The program was created
based on filtered back-projection method. An experimental CT setup (NMXCT) was
built by utilizing medical digital radiography scanning system in Malaysian Nuclear
Agency. The objectives are to perform a proof-of-concept of X-ray CT system, and to
validate the XRecon program. The target phantoms chosen for verification of the
XRecon program were two solid cylindrical Perspex blocks. The results demonstrate
that XRecon is suitable to reconstruct image from fan beam projections. In addition,
NMXCT system showed the ability to detect objects with minimum size of 2mm.It was
noticed that NMXCT system used in this study may have potential for imaging of
bigger sample. XRecon was also applied to scanned micro-CT data. Because of micro-CT
consists of cone beam projections, the optical axis projection data was selected, which
was acquired with fan beam geometry, and wasconverted to parallel beam data. The
reconstruction looks reasonable, but some artifacts are visible in the image. The
reconstruction time was observed to be less than a minute for 360 projections. The
results show that XRecon is able to reconstruct vertical center from cone beam
projections. The quality of reconstructed images using XRecon can be further improved
by appropriately designing filter functions.
Description
Keywords
Quantification of oleoresin in agarwood , digital image processing