摘要
To alleviate the distortion of XRII X-ray image intensifier images in the C-arm CT computer tomography imaging system an algorithm based on the Delaunay triangulation interpolation is proposed.First the causes of the phenomenon the classical correction algorithms and the Delaunay triangulation interpolation are analyzed.Then the algorithm procedure is explained using flow charts and illustrations. Finally experiments are described to demonstrate its effectiveness and feasibility. Experimental results demonstrate that the Delaunay triangulation interpolation can have the following effects.In the case of the same center the root mean square distances RMSD and standard deviation STD between the corrected image with Delaunay triangulation interpolation and the ideal image are 5.760 4 ×10 -14 and 5.354 2 ×10 -14 respectively.They increase to 1.790 3 2.388 8 2.338 8 and 1.262 0 1.268 1 1.202 6 after applying the quartic polynomial model L1 and model L2 to the distorted images respectively.The RMSDs and STDs between the corrected image with the Delaunay triangulation interpolation and the ideal image are 2.489 × 10 -13 and 2.449 8 ×10 -13 when their centers do not coincide. When the quartic polynomial model L1 and model L2 are applied to the distorted images they are 1.770 3 2.388 8 2.338 8 and 1.269 9 1.268 1 1.202 6 respectively.
针对扭曲的影像加强器(X-ray image intensifier,XRII)图像对后继工作产生不利影响的问题,提出使用Delaunay三角网插值对扭曲的XRII图像进行校正.首先分析了XRII图像扭曲的原因、经典的校正方法和Delaunay三角网插值;然后,使用程序流程图对算法过程进行了解释.最后,通过实验来证明所提算法的有效性和可行性.实验结果表明:在中心对齐时,使用Delaunay三角插值方法校正后的XRII图像网格线交叉点坐标值与理想校正靶网格线交叉点坐标值的残留误差和标准误差分别为5.760 4×10-14和5.354 2×10-14,使用经典的全局四次多项式、模型L1和模型L2校正之后残留误差和标准误差分别为1.790 3,2.388 8,2.338 8和1.262 0,1.268 1,1.202 6;在中心不对齐时,使用Delaunay三角插值方法校正后的XRII图像网格线交叉点坐标值与理想校正靶网格线交叉点坐标值的残留误差和标准误差分别为2.489×10-13和2.449 8×10-13,使用经典的全局四次多项式、模型L1和模型L2校正后残留误差和标准误差分别为1.770 3,2.388 8,2.338 8和1.269 9,1.268 1,1.202 6.
基金
The Natural Science Foundation of Anhui Province(No.1308085MF96)
the Project of Chuzhou University(No.2012qd06,2011kj010B)
the Scientific Research Foundation of Education Department of Anhui Province(No.KJ2014A186)
the National Basic Research Program of China(973 Program)(No.2010CB732503)
