Computed tomography with iterative reconstruction of thin cross-sectional planes
AssigneeHewlett-Packard Company
InventorJohn M. Heumann
Life of this patent
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Abstract
A cone-beam tomographic system in which computation speed is improved by reducing the reconstructed images to thin planes. Reducing the images to thin planes reduces the number of picture elements to be computed, and reduces basis functions to a simple function of the angle of a ray relative to a plane. In a variation, computation speed is further improved by making pixel size inversely proportional to the distance of a plane from an emissions source. As a result of the variable pixel size, for each projection, a ray intersecting the center of a sensor element intersects the center of exactly one pixel in each object plane.
Claims7
A method for computing an image for a tomographic system, the method comprising the following steps:
- approximating an object to be imaged as a plurality of planes, wherein the planes are at least partially non-adjacent, each plane comprising a plurality of voxels, each voxel having a top surface and a bottom surface opposite the top surface, wherein each plane is sufficiently thin so that there is essentially a zero probability of a ray entering or leaving a surface of any voxel other than the top surface or the bottom surface;
- and
- approximating a solution to ray equations for the planes.
Dependencies are inferred from the claim text.