基于双能量X射线透射技术的物质分类识别方法研究

Study on Object Classification Based on Dual-energy X-ray Transmission Technology

通过对单、双能量透射技术的比较分析发现由于入射能量的不同,相同原子序数物质的质量衰减系数的变化速度不同,即在双能量方式下,同一原子序数的物质对低能和高能X射线的吸收程度是不同的,这样通过低能、高能2个不同线吸收系数比较与运算,就可以从2种不同物质组成的、不同厚度产生的或相互重叠的图像中将不同种类的物体区分开。基于此原理将铝板和有机玻璃板作为基材,实验确定了物质分类识别边界曲线,并用已知物质验证了实验得到的边界曲线是有效的。

Compares the single and dual- ener- gy X - ray transmission technology and analyzes the difference between them. It is found that how the mass attenuation coefficients of two materials change are different even their atomic numbers are the same when the incident energies are different. It implies that when irradiated by dual energy X - ray,i, e. ,high and low energies are both absorbed, the absorptance of the two materials of the same atomic number are different. Thus the objects which are composed of two different materials/thicknesses or in overlapping image, can be differentiated from each other by way of calculating and compa- ring the different absorption coefficients as irradiated by low and high energy X - rays. In this way the aluminium plate and polymethyl methacrylate plate are taken as specimens to be tested, and the results show that the boundary curves to classify different materials are reliable.