Self-calibration of images for three-dimensional cone beam reconstruction

Computed Tomography (CT) combines x-ray images and provides cross-sectional views of a 3D object. A micro-cone-beam computed tomography (micro-CT) system also provides cross-sectional views but with much greater spatial resolution (∼0.05 mm). In this thesis, we present techniques for self-calibrating the system using the images themselves and without using calibration objects.; Projection images were obtained using an experimental micro-CT system. Flat-field and dark-field corrections and logarithmic conversion were performed. Exposure variations due to variations in x-ray tube output were determined by using the unattenuated regions in the projection images. Horizontal translations of the system during acquisition were determined using the analysis of sinograms. The image data were then shifted by the determined translations. The axis of rotation was determined by registering profiles from antiposed images using cross-correlation techniques.; Flat-field and dark-field corrections substantially reduced ring artifacts in the images. (Abstract shortened by UMI.)...