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摘要:目前太赫兹(Terahertz, THz)成像技术在许多领域被视为最前沿技术之一,经过20年的发展,取得了巨大进步。随着科研、医疗、军事以及工业应用需求的增长,高分辨率THz图像变得不可或缺。超分辨率成像是目前THz技术的研究热点。本文首先回顾了THz系统的成像方法,包括连续波成像与脉冲波成像两种方式;在此基础上,详细介绍了THz超分辨率成像系统与THz信号处理技术,其中超分辨率成像系统包括近场成像、超透镜以及太喷射装置等,THz信号处理技术包括超分辨率重建与卷积计算等;最后,通过分析目前超分辨率成像存在的不足,比如系统的制造工艺要求高、采集速度慢以及重建图像使用的学习样本分辨率较低等,从而进一步对超分辨率成像研究方向进行展望。Abstract:Terahertz (THz) imaging technology has recently become one of the most cutting-edge technologies in many fields and has made great progress in its development over the past two decades. With the increasing demands of scientific research, medical treatment, military and industrial applications, high-resolution THz images have become indispensable. To obtain high-resolution THz images, super-resolution imaging has become a research hotspot. In this paper, the imaging methods of a THz system are reviewed, including continuous wave imaging and pulse wave imaging. On this basis, THz super-resolution imaging systems and THz signal processing technologies are described in detail. The super-resolution imaging systems include near-field imaging, super lens and terajet effect, etc. The THz signal processing technologies could be grouped as either super-resolution reconstruction and convolution calculations. Finally, the shortcomings of current super-resolution imaging technologies were discussed. There are still some bottlenecks that need to be resolved such as the high manufacturing process requirements of the system, the slow acquisition speed, and the low resolution of the learning samples used to reconstruct images. With this analysis, the research direction of super-resolution imaging is proposed.
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图 3太赫兹近场成像方法示意图。(a)共焦法原理图[25];(b)波导法示意图[28];(c)孔径法示意图[31];(d)光导探针示意图[32];(e)光导探针测量过程示意图[32]
Figure 3.Principle diagram of Terahertz near field imaging method. (a) Schematic diagram of confocal method[25]; (b) schematic diagram of waveguide system[28]; (c) schematic diagram of aperture system[31]; (d) schematic diagram of photoconductive probe[32]; (e) schematic diagram of photoconductive probe measurement[32]
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