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《Journal of Graphics》 2017-04
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Correction Method of the Projection Images' Rotational Center Based on Sinogram

ZHAO Yuqing;CONG Changhong;HU Chunhong;JI Dongjiang;JIAN Jianbo;QIN Lili;SUN Mengyu;College of Biomedical Engineering, Tianjin Medical University;The Dental Hospital of Tianjin Medical University;The School of Science, Tianjin University of Technology and Education;  
Affected by the precision of instruments and other factors, CT turntable may cause the deviation of projection center of rotation(COR), which will seriously affect the quality of the reconstructed images. Thus, the precise correction of COR in projection images plays an important role in the CT reconstruction. In this paper, a method of measuring the address of COR is proposed based on the radon transform, which is suitable for the parallel beam scanning model. The method can be summarized as follows: the COR address of the projection is obtained using one half of the mean of the 0° and 180° projections' addresses in sinogram. According to the method, the data, which represent 0° and 180° projections in sinogram, were respectively copied by N times to get the image matrix A. The image matrix A was then segmented into binarization with the "Chan-Vese" method, and the 0° and 180° projections' addresses of sample were obtained to calculate the COR address of the projection. Finally, the COR value was regarded as the center of the sinogram, and the sinogram was clipped properly in the horizontal direction. The simulation and experiment show that this method can accurately correct the COR, which effectively improves the quality of the reconstructed images. method can accurately correct the COR, which effectively improves the quality of the reconstructed images.
【Fund】: 国家自然科学基金项目(81371549 81671683);; 天津市自然科学基金项目(16JCYBJC28600);; 天津市卫计委科技基金项目(2015KZ111)
【CateGory Index】: TP391.41
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