Acta Optica Sinica, Vol. 39, Issue 12, 1234001 (2019)
Suppression of Weighting Artifact in Computed Tomography Detector-Displaced Reconstruction
Chen Yunbin1,2,*, Liu Qinghua1,2, Wang Yuan1,2, and Zhang Chengxin1,2
- 1Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China
- 2National X-Ray Digital Imaging Instrument Center, Mianyang, Sichuan 621000, China
Based on the redundant property of projection data, the common reconstruction algorithm for the detector-displaced scan weighs the projection data for normalization function, and then reconstructs CT images using a standard filtered back projection method. However, in the condition of a narrow weighting region, the circular weighting artifact is generated in the center area of the image because of the fast attenuation of weighting function. This study proposes a correction scheme for weighting artifacts. First, a virtual detector is used to extend the weighting region. Second, the missing projection data corresponding to the virtual detector can be interpolated by conjugate and forward projection. Finally, the interpolated projection data is reconstructed by the detector-displaced scan reconstruction algorithm. The detector-displaced scan projection data with various weighting region sizes is reconstructed herein. The experimental result shows that the proposed correction method can effectively suppress the weighting artifact.
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