CT扫描的岩心分析精度

采用医用X-CT机进行岩心分析时，会产生射束硬化现象，因此在重建图像之前，必须对投影数据进行预处理，校正射束硬化现象。硬化校正不足时，边缘的CT值偏高，中间的CT值偏低;校正过量时，则有相反情况出现。为了提高岩心分析精度，文中对用于岩心分析的专用X-CT机的结构和图像处理软件提出了一些具体要求。笔者认为，只要直接从X-CT机中取出原始数据进行预处理，再重建图像，就可解决射束硬化校正问题。如果在不同电压下，进行两次扫描，然后利用这两组原始数据(用双能量迭代法)即可求出物质的原子序分布图和电子密度分布图。这样，不仅消除了射束硬化影响，而且一在一定程度土解决了多解性。

Accuracy of CT core analysis

Beam hardening happens when medical X- CT machine is used in core ana1ysis;therefore,projection data must be preprocessed to correct (or remove ) the beamhardening before the image reconstruction. In the case of undercorrection,marginalCT data are on the high side,and mid ones the low side. However,overcorrection results in a contrary situation.Requirements for both the hardwares of X- CT machine and the image processing softwares are defined in order to improve core analysis accuracy. The beamhardening can be removed by first preprocessing raw data in the X-CT machine,thenreconstructing the images. The atomic number and electron density distributions of asubstance can be obtained by using dual erergy iteration and two sets of data whichhave been respectively produced after two scannings under different voltages. Thus,beam hardening is removed,and multi-solution phenomenon is reduced.