Date of Award
Master of Science (MS)
Dr Usman Tariq
Phase unwrapping is a classic signal processing problem and an unavoidable procedure that can be faced with in a variety of applications which are interested in the phase, such as synthetic aperture radar (SAR), field mapping in magnetic resonance imaging (MRI), wavefront distortion measurement of adaptive optics, interferometry, and surface shape measurement. Although phase unwrapping is one of the most challenging tasks in signal processing because of the presence of residues, noise in the data, discontinuities or other phase particularities, there are many successful phase unwrapping techniques and algorithms that have been developed in the last decades. In this thesis, we present a modified algorithm based on the Andris‟s method which is dependent on the difference in two echo times (TE). The proposed algorithm is confirmed by using simulated phase MR data which are highly distorted by large magnetic field inhomogeneity (∆B) or long echo time (TE). The approach is evaluated by comparison to other unwrapping algorithms and results show that the proposed algorithm has better accuracy.
Ali Al Hassani, Shamma Ali Rashed, "Unwrapping MRI Phase by Using Multi-Echo Technique" (2017). Theses. 618.