单探测器快速扫描被动太赫兹人体成像系统

Passive Terahertz Imaging System for Fast Scanning of Human Body by a Single Detector

报道了一种单探测器快速扫描准光学被动太赫兹人体成像系统,并设计了成像分辨率测试卡。该成像系统的光路由反射式准光学器件构成。被检测人员自身辐射的太赫兹波通过成像系统的透波窗口进入设备,依次经过摆动反射镜、旋转反射镜、聚焦反射镜和固定反射镜后到达太赫兹探测器。该成像系统仅用一个太赫兹探测器,配合由旋转反射镜和摆动反射镜组成的扫描机构,就可在2.5 s的时间内完成对一个距离设备1.5 m处0.65 m×1.9 m区域的完整成像,成像线分辨率达到2 cm。该成像系统不仅可有效显示金属、液体、陶瓷和粉末等材料的可疑危险物品的轮廓,还可对太赫兹图像上显示出的携带物品进行自动标记。

In this paper, a passive quasi-optical terahertz imaging system for a human body based on a single detector with fast scan mechanism is presented. A resolution test chart for image quality evaluation is designed. The proposed imaging system comprises several reflection quasi-optical devices. Terahertz waves emitted from the human body were transmitted through a terahertz window into the imager and were sequentially reflected by a flapping mirror, rotating mirror, focusing mirror, and fixed mirror and finally reached the terahertz detector. The imaging system can obtain a full image of 0.65 m×1.9 m using only one detector, with a resolution of 2 cm and an imaging distance of 1.5 m within 2.5 s using a fast scanning mechanism comprising a flapping mirror and a rotating mirror. The imaging system is capable of displaying the profiles of suspected dangerous items carried on the human body, such as metals, liquids, ceramics, and powders. The detected items are automatically marked by software.