Shearlet-Based Regularized Roi Reconstruction In Fan Beam Computed Tomography
WAVELETS AND SPARSITY XVI(2015)
摘要
Region-of-interest (ROT) reconstruction in computed tomography (CT) is a problem receiving increasing attention in the medical imaging community, due to its potential to lower exposure to X-ray radiation and to reduce the scanning time. Since the ROT reconstruction problem requires to deal with truncated projection images, classical CT reconstruction algorithms tend to become very unstable and the solution of this problem requires either ad hoc analytic formulas or more sophisticated numerical schemes. In this paper, we introduce a novel approach for ROT CT reconstruction, formulated as a convex optimization problem with a regularized functional based on shearlets or wavelets. Our numerical implementation consists of an iterative algorithm based on the scaled gradient projection method. As illustrated by numerical tests in the context of fan beam CT, our algorithm is insensitive to the location of the ROT and remains very stable also when the ROT size is rather small.
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关键词
Computed tomography, region-of-interest reconstruction, shearlets, wavelets, gradient projection methods
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