[Background] No currently available back scatter scanning systems appear to produce colorized materials-discrimination images. [Purpose] This study aims to propose a new method for material identification to throw light on detecting contraband such as metal knives, explosive devices, narcotics and so on. [Methods] X-ray dual-energy backscatter technique was employed to detect backscatter signals. Monte Carlo simulation and empirical experiments were used to determine the classification curve of material identification. By analyzing the backscatter imaging of material under test from dual-energy detectors of a backscatter scanner, material property information such as the effective atomic number was obtained. Furthers, the curves were used to colorize backscatter images of examples, referring to the high/low method on transmission technology. [Results & Conclusion] By using dual-energy detectors, material identification can be realized in backscatter scanning systems. This method is greatly influenced by photon counting quantity, hence more effort should be paid on improving signal-to-noise-ratio (SNR) of the whole system accounting.%本文提出了一种新的物质分类识别方法,为探测金属刀具、爆炸装置和毒品等违禁品提供新思路.该方法采用分能域的X射线背散射探测成像方法,通过分析被测物质在高低两种能量下的背散射信号来获得被测物质的等效原子序数信息;经过蒙特卡罗仿真与实验验证确定了物质分类识别曲线,并仿照双能透视物质分类着色方法对背散射扫描图像中不同等效原子区间的物质进行着色.研究发现该方法受光子计数量影响较大,通过提升探测器信噪比可以增强背散射扫描系统的物质识别能力.
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