摘要
双能CT能够用来检测物质的有效原子序数和电子密度,可区别密度相近而原子序数不同的物质。物质的有效原子序数和电子密度的精确性是双能CT重建的关键。针对得到的有效原子序数和电子密度图中的噪声,将全变差(TV)最小化应用到双能CT中。衰减系数分解模型选用基材料分解模型,首先对高低能投影进行投影匹配,得到两组基材料分解系数投影,然后用滤波反投影(FBP)重建算法重建得到分解系数,接着得到有效原子序数和电子密度图,最后用基于TV最小化的算法处理以上两组数据。仿真实验结果表明,双能CT可以检测出物质的有效原子序数和电子密度,引入TV的双能CT重建算法能得到质量较好的物质的电子密度和有效原子序数图,更利于物质的检测。
Dual energy X-ray computed tomography（CT） can be used for detecting the effective atomic number and electrondensity of materials, distinguishing materials with similar density but different atomic number. The accurate of the materials＇effective atomic number and electron density are very important to the reconstruction of the dual energy CT. In accordance withthe noise of the obtained effective atomic number and electron density images,total variation（TV） minimization was applied indual energy CT. Decomposition model of the attenuation coefficient was expressed by basis material decomposition model. First-ly, this paper realized the projection matching of high and low projections to get two sets of basis material projections of decom-position coefficient. Secondly, the decomposition coefficient could be obtained by the use of filtered backprojection（FBP） re-construction algorithm, and then could get the effective atomic number and electron density images. Finally, algorithm whichwas based on TV minimization was used to process the above data. The experimental results show that dual energy CT can ob-tain the effective atomic number and electron density of materials, meanwhile, with the introduction of TV, dual energy CT re-construction is capable of getting better quality images of materials＇ effective atomic number and electron density, and is moreconducive to materials＇ detection.
出处
《计算机应用研究》
CSCD
北大核心
2012年第3期1158-1161,共4页
Application Research of Computers
基金
国家自然科学基金资助项目(60972104)
重庆市教委科研项目(KJ111502)
关键词
双能CT
滤波反投影重建
全变差最小化
基材料分解
图像降噪
有效原子序数和电子密度
dual energy CT
filtered backprojection reconstruction
total variation minimization
basis material decomposi-tion
image denoising
effective atomic number and electron density
