微量爆炸物激光辐照成像探测的数值分析和实验研究

Numerical Simulation and Experimental Study of Trace Explosives Detection by Laser Illumination and Imaging

为了研究激光探测爆炸物时的相关现象，首先对激光辐照目标过程进行理论分析，并通过有限元软件ANSYS进行仿真，建立CO2激光器辐照爆炸物温升分布的三维立体模型，然后利用CO2激光器和扩束系统对目标进行照射（距离3m），同时配合8～14μm的红外成像设备分别观察得到沾有少量三硝基甲苯（TNT）和黑索金（RDX）的目标热像图。研究表明，在一定功率的激光辐照下，由于爆炸物和背景的有效辐射出射度大小分别由其在8—14μm波段的吸收率和对激光辐射照度的反射率共同决定，因而可得到爆炸物与背景区域明显不同的热像图。此外，辐照功率和照射时间的变化也可能是影响探测效果的重要因素。

To analyze the phenomenon related to the detection of explosives by laser illumination and imaging, theoretical analysis of the process of the laser illumination on the target is carried out firstly. The simulation is implemented with the software ANSYS. Three- dimensional models are built for the study of temperature distribution. A CO2 laser is used with expanded beam to irradiate the target （3 m away）, and obtain thermal images （8-14μm） of the targets with TNT and RDX residues. Studies show due to the effective radiation of explosive and background is determined by the emissivity and reflectivity in 8-14 9m waveband when laser irradiation at a certain power, the explosives and the substrate have significant difference in thermal images. Moreover, irradiation power and time difference may also be important factors affecting the detection.