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Proceedings Paper

Cupping artifacts analysis and correction for a FPD-based cone-beam CT
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Paper Abstract

Cupping artifact is one of the most serious problems in a middle-low energy X-ray Flat panel detector (FPD)-based cone beam CT system. Both beam hardening effects and scatter could induce cupping artifacts in reconstructions and degrade image quality. In this paper, a two-step cupping-correction method is proposed to eliminate cupping: 1) scatter removal; 2) beam hardening correction. By experimental measurement using Beam Stop Array (BSA), the X-ray scatter distribution of a specific object is estimated in the projection image. After interpolation and subtraction, the primary intensity of the projection image is computed. The scatter distribution can also be obtained using convolution with a low-pass filter as kernel. The linearization is used as beam hardening correction method for one-material object. For two-material cylindrical objects, a new approach without iteration involved is present. There are three processes in this approach. Firstly, correct raw projections by the mapping function of the outer material. Secondly, reconstruct the cross-section image from the modified projections. Finally, scale the image by a simple weighting function. After scatter removal and beam hardening correction, the cupping artifacts are well removed, and the contrast of the reconstructed image is remarkably improved.

Paper Details

Date Published: 2 February 2006
PDF: 10 pages
Proc. SPIE 6065, Computational Imaging IV, 60650Z (2 February 2006); doi: 10.1117/12.650503
Show Author Affiliations
Li Zhang, Tsinghua Univ. (China)
Hewei Gao, Tsinghua Univ. (China)
Shuanglei Li, Tsinghua Univ. (China)
Zhiqiang Chen, Tsinghua Univ. (China)
Yuxiang Xing, Tsinghua Univ. (China)

Published in SPIE Proceedings Vol. 6065:
Computational Imaging IV
Charles A. Bouman; Eric L. Miller; Ilya Pollak, Editor(s)

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