In many object recognition systems only geometric constraints on the boundaries of the objects are used. Many authors have shown the merit in determining the distinctiveness of boundary constraints, and using these to speed up and improve the robustness of object recognition algorithms. However, if the objects have variable shapes or the image is cluttered,… (More)
A method of reducing respiratory artefact when using the spin warp technique of magnetic resonance imaging is described. A respiratory signal is used to determine the order in which the rows of the data matrix are measured. The aim is to make the respiratory signal at the time of each phase encoding gradient a slowly varying function of the time integral of… (More)
A nuclear magnetic resonance (NMR) machine constructed by Thorn-EMI Ltd was used to produce tomographic images of the brain in eight volunteers and fourteen patients. The use of an inversion recovery technique designed to emphasise variations in the spin-lattice time constant (T1) resulted in remarkable differentiation between grey and white matter in all… (More)
This note considers the anomolous contrast in inversion recovery images produced by NMR scanners if a map of [My] is reconstructed, rather than a map of My'.
The results of NMR examinations in 52 patients with histological or clinical diagnoses of cerebral tumor are reviewed. An increase in relaxation time was recognized in all tumors but problems were experienced in distinguishing the margin of tumors from surrounding edema. Mass effects were well demonstrated as a result of the high level of gray-white matter… (More)