Jeffrey Brokish

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Existing algorithms for exact helical cone beam (HCB) tomographic reconstruction involve a 3-D backprojection step, which dominates the computational cost of the algorithm. We present a fast hierarchical 3-D backprojection algorithm, generalizing fast 2-D parallel beam and fan beam algorithms, which reduces the complexity of this step from O(N/sup 4/) to(More)
The sampling requirements of tomographic projection data are determined by the set of frequencies occupied by the Fourier transform of the projection data. This region of essential support has been analyzed for various 2-D geometries. The general case of 3-D cone beam projections, using a 2-D detector array, is mainly unexplored. In this paper, we consider(More)
This is the first report on a new fast statistical iterative reconstruction algorithm for conebeam with a circular source trajectory, accelerated by InstaRecon's fast O(NlogN) hierarchical cone beam backprojection and reprojection algorithms. We report on the results of image quality and run-time comparisons with iterative algorithms based on conventional(More)
We describe the first implementation and performance of a fast O(N<sup>2</sup>logN) hierarchical backprojection (FHBP) algorithm on a field programmable gate array (FPGA) platform. The resulting prototype tomographic backprojection system for 2D fan-beam geometry combines speedup through algorithmic improvements provided by the FHBP algorithm, with speedup(More)
The sampling requirements in fan-beam tomography are well known and provide an estimate of the number of projections required for accurate reconstruction of the entire image. Here we consider the problem of reconstructing a small, off-center subregion of the object. We show that a subregion can be reconstructed from a smaller set of projections, reducing(More)
This paper introduces a new version of a fast and accurate O(N<sup>3</sup>logN) reconstruction algorithm for cone-beam CT with a circular source trajectory. This is the first report on the performance of this algorithm with high-resolution large-matrix Micro-CT data. We determined that a software implementation of the FHBP algorithm on off-the-shelf(More)
Existing algorithms for exact helical cone beam tomographic reconstruction involve a 3-D backprojection step, which dominates the computational cost of the algorithm. Hierarchical backprojection reduces the complexity of this step from O(N/sup 4/) to O(N/sup 3/logN), greatly accelerating the reconstruction process. Here the performance of the hierarchical(More)