TY - GEN
T1 - Exact technique for weighting function calculation in 3D cone-beam reconstruction
AU - Sen, Anindya
AU - Hsiung, Hsiang Hsin
AU - Patel, Maqbool
AU - Schueler, Beth A.
AU - Holte, James E.
AU - Hu, Xiaoping
PY - 1995
Y1 - 1995
N2 - The exact weighting function in 3D image reconstruction from 2D projections with cone beam geometry is obtained as the volume of intersection of a pyramidal ray with a cubic voxel. This intersection yields a convex polyhedron whose faces are formed by either the side of the pyramid or the voxel face. For each face of a voxel, we maintain a vertex link map. When one of the four pyramidal ray planes clips the voxel, we obtain a new face and a set of new vertices, while updating existing faces and their vertex link maps. Progressively clipping the voxel by the necessary ray planes yields the intersection polyhedron, whose faces and vertices are provided by the face list and its associated vertex link maps. To generate the weight, the volume of the polyhedron is calculated by dividing the polyhedron into tetrahedrons, whose volumes are summed. The exact calculated weights were used to reconstruct 3D vascular images from simulated data using a ROI (region of interest) limited ART (algebraic reconstruction technique). Comparing the results to those obtained from length approximation indicates that more accurate reconstruction could be achieved from the weights calculated with the new method.
AB - The exact weighting function in 3D image reconstruction from 2D projections with cone beam geometry is obtained as the volume of intersection of a pyramidal ray with a cubic voxel. This intersection yields a convex polyhedron whose faces are formed by either the side of the pyramid or the voxel face. For each face of a voxel, we maintain a vertex link map. When one of the four pyramidal ray planes clips the voxel, we obtain a new face and a set of new vertices, while updating existing faces and their vertex link maps. Progressively clipping the voxel by the necessary ray planes yields the intersection polyhedron, whose faces and vertices are provided by the face list and its associated vertex link maps. To generate the weight, the volume of the polyhedron is calculated by dividing the polyhedron into tetrahedrons, whose volumes are summed. The exact calculated weights were used to reconstruct 3D vascular images from simulated data using a ROI (region of interest) limited ART (algebraic reconstruction technique). Comparing the results to those obtained from length approximation indicates that more accurate reconstruction could be achieved from the weights calculated with the new method.
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M3 - Conference contribution
AN - SCOPUS:0029453917
SN - 0819417807
SN - 9780819417800
T3 - Proceedings of SPIE - The International Society for Optical Engineering
SP - 616
EP - 626
BT - Proceedings of SPIE - The International Society for Optical Engineering
A2 - Van Metter, Richard L.
A2 - Beutel, Jacob
T2 - Medical Imaging 1995: Physics of Medical Imaging
Y2 - 26 February 1995 through 27 February 1995
ER -