太赫兹孔径编码成像分辨性能研究

摘要

太赫兹孔径编码成像综合了光学孔径编码成像和微波关联成像的基本原理,通过孔径编码天线改变目标区域太赫兹波空间幅相分布来实现高分辨、高帧率、前视凝视成像.基于孔径编码天线,该文设计了雷达成像系统和准光扫描光路,可同时实现系统孔径编码和波束扫描功能,理论推导并仿真分析了其成像质量影响因素,并在此基础上比较了不同算法对孔径编码成像分辨性能的影响,证明了稀疏重构类算法对孔径编码成像的优势,最后对比了孔径编码成像和同尺寸阵列实孔径成像的结果,论证出孔径编码成像系统具有高分辨,易于小型化,成本较低等优点.该成像方式可广泛应用于战场侦查、安检反恐和末制导等领域.%Terahertz coded-aperture imaging follows the basic principles of optical coded-aperture imaging and microwave coincidence imaging and is a novel imaging technique. Herein, the wave spatial distribution or illumination pattern is usually obtained by a sub-reflector antenna. Terahertz coded-aperture imaging has some significant advantages such as a high frame rate, high resolution, and ability of forward-looking and staring imaging. To achieve simultaneous functions of aperture coding and beam scanning, we designed a terahertz coded-aperture imaging system that utilizes digital sub-reflector antenna and quasi-optical techniques. Based on this system, we deduce and simulate the influencing factors on its resolution. Then, different algorithms are applied to the imaging model in order to verify the superiority of sparse reconstruction for coded-aperture imaging. Finally, we compare the imaging results of our imaging system and that of a traditional real aperture imaging structure for the same simulation parameters. The results prove that our imaging system performs better with high resolution, small volume, and low cost. This new imaging technique can be applied to areas such as battlefield reconnaissance, security checks, anti-terrorism, and terminal guidance.