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Utilisation of phase contrast in X-ray computed tomography
Kalasová, Dominika ; Švéda,, Libor (referee) ; Zikmund, Tomáš (advisor)
X-ray computed tomography is a nondestructive method for 3D imaging of inner structure of objects; it is, however, restricted by absorption properties of materials. With phase contrast imaging, observation of samples with low absorption or with parts with similar absorption becomes possible. For a long time, phase contrast imaging has been restricted to synchrotron radiation sources or special techniques due to requirement of spatial coherence of radiation. Along with recent development of X-ray micro and nanofocus tubes and X-ray detectors a phase contrast imaging becomes available also with laboratory sources. In this work an overview of phase contrast imaging methods is given, with an emphassis on propagation based method. Examples of this method and application of phase retrieval algorithm on samples from RIGAKU Nano3DX and GE phoenix v|tome|x L240 stations within Laboratory of X-ray micro and nanotomography CEITEC BUT are shown.
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Optimization of X-ray computed tomography method for imaging of low-density materials
Maleček, Lukáš ; Oberta, Peter (referee) ; Zikmund, Tomáš (advisor)
X-ray computed tomography is a technique enabling three-dimensional non-destructive imaging of the internal structure of measured objects. This imaging method has become a standard tool utilized in various fields, including medicine, industry, and science. Conventional X-ray computed tomography is based on the absorption of X-rays as it is passing through the measured object. However, this conventional imaging approach has its limitations, particularly when imaging objects with low density that causes only low X-ray attenuation. In such cases, sufficient contrast between the measured object and the background is not achieved. This thesis focuses on the optimization of phase contrast imaging, which utilizes phase changes of radiation as it is passing through the sample to overcome the limitations of absorption-based computed tomography. The detection of phase changes is achieved in the thesis using the propagation-based method. The main goal is to develop a methodology for finding the optimal parameters for the acquisition of tomographic data and also for the following processing of obtained X-ray projections. The results are qualitatively and quantitatively evaluated to assess the benefits of the developed methodology.
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Utilisation of phase contrast in X-ray computed tomography
Kalasová, Dominika ; Švéda,, Libor (referee) ; Zikmund, Tomáš (advisor)
X-ray computed tomography is a nondestructive method for 3D imaging of inner structure of objects; it is, however, restricted by absorption properties of materials. With phase contrast imaging, observation of samples with low absorption or with parts with similar absorption becomes possible. For a long time, phase contrast imaging has been restricted to synchrotron radiation sources or special techniques due to requirement of spatial coherence of radiation. Along with recent development of X-ray micro and nanofocus tubes and X-ray detectors a phase contrast imaging becomes available also with laboratory sources. In this work an overview of phase contrast imaging methods is given, with an emphassis on propagation based method. Examples of this method and application of phase retrieval algorithm on samples from RIGAKU Nano3DX and GE phoenix v|tome|x L240 stations within Laboratory of X-ray micro and nanotomography CEITEC BUT are shown.
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