TY  - GEN
ID  - heidok32035
Y1  - 2022///
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/32035/
AV  - public
A1  - Trapp, Philip Maurice
CY  - Heidelberg
N2  - Systematic and statistical measurement deviations, as well as insufcient spatial resolution of the image data, can severely degrade the image quality in x-ray computed tomography (CT) and thus limit the application of CT for medical and industrial purposes. This dissertation therefore deals with the reduction of such measurement deviations under the aspect of simultaneously optimal spatial resolution of the CT datasets. The empirical scatter correction (ESC) is presented as an algorithm that e?ectively reduces systematic measurement deviations due to scattered photons without specifc prior knowledge about the measured object, the CT system, or acquisition parameters. Furthermore, this work proposes the frequency split dual energy computed tomography (FSDECT), a method for CT systems with two x-ray tubes that reduces systematic measurement deviations due to the polychromatic x-ray spectrum and the energy-dependent attenuation behavior of matter. Compared to existing dual energy computed tomography (DECT) methods for reducing systematic measurement deviations, the resulting fusion volume dataset has an increased spatial resolution. The feasibility of reducing systematic measurement deviations in CT using novel energy-selective detectors is also reviewed in this work and possible benefts compared to non-energy-selective detectors are discussed. To reduce statistical measurement deviations, which negatively a?ect the reproducibility of measurement results in addition to a decrease of image quality, a guided bilateral flter is proposed. By improving the image quality with the correction methods presented in this dissertation, internal features of a sample workpiece can be measured with high repeatability using CT measurements, which is not possible without these methods due to excessive measurement deviations.
TI  - Novel Methods for the Reduction of Systematic and Statistical Measurement Deviations and Spatial Resolution Optimization in X-Ray Computed Tomography
ER  -