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Proceedings Paper

Accurate perspective projection calculation using a pixel-pyramid model for iterative cone beam reconstruction
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Paper Abstract

The calculation of perspective projection is the essential part in either cone-beam projection or realistic volume rendering. In this paper, we propose a pixel-pyramid model to accurately calculate pixel values in flat-panel-based cone-beam reconstruction. This model faithfully portrays the divergent beam projection on a grilled planar detector. It consists of a pyramidal base (detector pixel facet) and an apex (X-ray source). Through spatial clipping by a flat-panel detector (FPD), a cone is tailored into a pyramid with the base at the FPD, called FPD pyramid, which is then spatially decomposed into pyramidal elements (PYREL). During cone-beam projection, a PYREL intersects the 3D object and produces a frustum, wherein the voxels are accumulated to produce a pixel value. In backprojection, the pixel value is imparted to the same contributive voxels. A voxel’s weight (contribution to a PYREL) is determined by spatial overlapping, which is a piecewise linear function. Through iterative algorithm, accurate cone beam reconstruction is achieved. Since the pyrel model portrays the perspective projection geometry and the voxel weight in a more natural fashion, it can be used for accurate calculation of perspective projection, especially in dealing with severe incomplete data. Simulations and comparisons are provided.

Paper Details

Date Published: 5 June 2003
PDF: 12 pages
Proc. SPIE 5030, Medical Imaging 2003: Physics of Medical Imaging, (5 June 2003); doi: 10.1117/12.480196
Show Author Affiliations
Zikuan Chen, Univ. of Rochester (United States)
Ruola Ning, Univ. of Rochester (United States)
David L. Conover, Univ. of Rochester (United States)

Published in SPIE Proceedings Vol. 5030:
Medical Imaging 2003: Physics of Medical Imaging
Martin J. Yaffe; Larry E. Antonuk, Editor(s)

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