CT理论与应用研究2000，Vol.9Issue(z1)：13-22,10.
CT图象重建的算法优化和代码优化
Algorithm Optimization and Code Optimization of CT Image Reconstruction
摘要
Abstract
Filtered Backprojection is the most important algorithm for CT image reconstruction. As a linear processing, the algorithm is not so complex. The computation of image reconstruction is, however, very time consuming, because of the huge amount of data of CT.Most CT scanners made by foreign companies use workstations with 64-bit CPU together with some array processing board specially made for CT image reconstruction. Such an expensive (costing tens of thousands US dollars) computer system will be very heavy burden for ordinary hospitals. On the contrary, we have been using general-purpose PC workstations, which have not only lowered cost but also been able to be upgraded rapidly. Then, we have to optimize the algorithm to satisfy the need of reconstruction speed from clinical diagnostics and treatment. The effect of optimization is critical for the CT software to be practical.The optimization work in algorithm and in coding is summarized in this paper. First, for algorithm implementation, (1) in the backprojection algorithm, the outer and inner loops are exchanged, making the computation in the innermost loop decreased to minimal; (2) only part of the image data are computed and the rest are can be obtained by the symmetry of backprojection;(3) the computation is automatically adjusted according to different field of view; (4) the efficiency of real data FFT is doubled using complex data FFT; (5) data is transposed to raise the memory accessing of CPU. Second, for coding, using the new resource and new instructions of Pentium III and some optimization tools, we rewrite the codes of critical parts of the algorithm to raise the execution efficiency of the program. It is shown by the practical testing on NEUALPINE's CT-C2000 scanner, that running speed of CT image reconstruction is raised for 8 times, satisfying the requirements from hospitals.关键词
CT/图象重建/优化Key words
Computer Tomography/Image Reconstruction/Optimization引用本文复制引用
江根苗,连兵,刘晋军,王怀志..CT图象重建的算法优化和代码优化[J].CT理论与应用研究,2000,9(z1):13-22,10.
