hig.sePublications
Planned maintenance
A system upgrade is planned for 10/12-2024, at 12:00-13:00. During this time DiVA will be unavailable.
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Development of Advanced X-ray Micro-Tomography Helical Scan andTomographic Data Processing
University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science.
2023 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Micro-computed tomography (Micro-CT) is an imaging technique that allows for high-resolution,three-dimensional (3D) internal visualization of small objects in a non-destructive manner. However,a significant limitation arises when attempting to image elongated samples at higher resolutions andmagnifications due to the inherently small field of view (FOV). This thesis project introduces anapproach aimed at overcoming this limitation by combining helical scanning with the utilization ofthe open-source Astra Toolbox. The toolbox provides flexible scanning geometry parametrizationand facilitates tomographic reconstruction using the Feldkamp-Davis-Kress (FDK) algorithm.Helical data scanning represents a departure from traditional data acquisitions. Instead ofcapturing data at a fixed height, helical scanning acquires data by rotating and translating theimaged sample. This acquisition process extends the effective FOV, enabling the reconstruction oflarger samples. To illustrate this approach, a micro-CT helical scan was performed on a pencil asan elongated sample and compared with a conventional circular scan.While Micro-CT is a powerful imaging tool, it faces challenges when imaging weakly attenuating materials with hard X-rays. X-ray radiation possesses both amplitude and phase components,but conventional CT can only capture intensity information. This limitation often leads to poorcontrast in images of weakly absorbing samples. To address this issue, the project also designedpost-processing software to enhance CT image quality through phase retrieval. Phase informationprovides better contrast for small structures of weakly absorbing materials compared to intensityalone. The Paganin phase-retrieval algorithm is employed to retrieve this phase information, resulting in improved contrast-to-noise ratio (CNR) in tomographic reconstructions and subsequentsegmentation. As a result, the generated images exhibit sharper delineations and offer a morecomprehensive representation of the sample’s internal structure, especially after 3-D rendering.In summary, in this thesis, I designed the micro-CT procedure both from acquisition with anadvanced helical scanning technique and from a post-processing point of view through designingsoftware with a phase retrieval algorithm. The project has improved the conventional microCT intwo aspects, namely the field of view and the phase contrast. 

Place, publisher, year, edition, pages
2023. , p. 61
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:hig:diva-43366OAI: oai:DiVA.org:hig-43366DiVA, id: diva2:1816554
External cooperation
Stockholm University Brain Imaging Center
Subject / course
Electronics
Educational program
Electronics/Automation – master's programme (two years) (sv or eng)
Presentation
2023-09-14, 11:320, Kungsbäcksvägen 47, 801 76, Gävle, 12:45 (English)
Supervisors
Examiners
Available from: 2023-12-05 Created: 2023-12-03 Last updated: 2023-12-05Bibliographically approved

Open Access in DiVA

fulltext(17300 kB)141 downloads
File information
File name FULLTEXT01.pdfFile size 17300 kBChecksum SHA-512
ab880cf047490efaddab3204c5778c83358092809d18516d9eb52b07cab3eaaa3add3fddb393b3f5a4c84df5f5cec5e848a11fe2a7e172bde6e46965797bbc03
Type fulltextMimetype application/pdf

By organisation
Department of Electrical Engineering, Mathematics and Science
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 141 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 482 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf