Atalar, Ergin2016-01-082016-01-081991http://hdl.handle.net/11693/18513Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Science of Bilkent Univ., 1991.Thesis (Ph.D.) -- Bilkent University, 1991.Includes bibliographical references.It is shown that the expansion/shrinkage and rotational motions of the body cause phase and amplitude distortions and non-rectangular sampling over the A:-domain. If these distortions are not compensated then the reconstructed image will suffer from ''the motion artifact'. The mathematical relation between motion and motion artifact is given. If the motion of the body is known, it is possible to obtain motion artifact free images. The motion is estimated either by using the information in the acquired data or by direct measurement. These estimates and the relation between motion and artifact are used to compensate the phase and amplitude distortions. Using the non-rectangular samples over the ¿-domain the rectangular samples are obtain by the aid of the singular value decomposition method. And finally, the inverse Fourier transform of these calculated samples gives the motion artifact free image. The proposed method is tested by simulations. For the estimation of the motion, two methods are proposed and tested. The first method is an iterative image reconstruction method. The second one uses the navigator echoes to obtain the amount of motion.x, 144 leaves, illustrationsEnglishinfo:eu-repo/semantics/openAccessMagnetic Resonance ImagingMotion Artifact Reduction in MRIRespiratory Motion ArtifactWN185 .A83 1991Magnetic resonance imaging--Methods.Image reconstruction--Mathematics.Thesis