In recent years, terahertz imaging has attracted great attention due to its advantages including penetrability and nondestructive property. The field imaging technology within the terahertz range is expected to enhance the terahertz image quality and improve its application effect. In this paper, an experiment on the data acquisition and digital refocusing of the terahertz light field was conducted. Firstly, the basic principle, system structure, and the method of reconstructing light field imaging were analyzed. Secondly, the terahertz focal plane array camera was used to collect the data about light field and digital refocusing was used to get the computed imaging. Finally, the reconstructed image was enhanced to obtain higher depth resolution, angle resolution, and object contour resolution. Experimental results showed the feasibility and ability of terahertz light field imaging to improve image quality and enrich retrieval effects.
An experimental study on terahertz light field data acquisition and digital refocusing
First published at:May 15, 2020
 Su J H, Jin Y T, Lu Y D, et al. Simulation of the algorithms for the light field image rendering[J]. Optical Instruments, 2017, 39(1): 31–40.
速晋辉, 金易弢, 陆艺丹, 等. 光场图像重构算法仿真[J]. 光学仪器, 2017, 39(1): 31–40.
 Nie Y F, Xiang L B, Zhou Z L. Advances in light field photography technique[J]. Journal of the Graduate School of the Chinese Academy of Sciences, 2011, 28(5): 563–572.
聂云峰, 相里斌, 周志良. 光场成像技术进展[J]. 中国科学院研究生院学报, 2011, 28(5): 563–572.
 Gershun A. The light field[J]. Journal of Mathematics and Physics, 1939, 18(1–4): 51–151.
 Gabor D. A new microscopic principle[J]. Nature, 1948, 161(4098): 777–778.
 Levoy M, Hanrahan P. Light field rendering[C]//Proceedings of the 23rd Annual Conference on Computer Graphics and Interactive Techniques, 1996: 31–42.
 Zhao G Z. Progress on terahertz science and technology[J]. Foreign Electronic Measurement Technology, 2014, 33(2): 1–6, 20.
赵国忠. 太赫兹科学技术研究的新进展[J]. 国外电子测量技术, 2014, 33(2): 1–6, 20.
 Hu B B, Nuss M C. Imaging with terahertz waves[J]. Optics Letters, 1995, 20(16): 1716–1718.
 Xu J M, Chen L, Zang X F, et al. Triple-channel terahertz filter based on mode coupling of cavities resonance system[J]. Applied Physics Letters, 2013, 103(16): 161116.
 Yao J Q. Introduction of THz-wave and its applications[J]. Journal of Chongqing University of Posts and Telecommunications (Natural Science Edition), 2010, 22(6): 703–707.
姚建铨. 太赫兹技术及其应用[J]. 重庆邮电大学学报(自然科学版), 2010, 22(6): 703–707.
 Jain R, Grzyb J, Pfeiffer U R. Terahertz light-field imaging[J]. IEEE Transactions on Terahertz Science and Technology, 2016, 6(5): 649–657.
 Xiao Z L. Camera array based light field imaging and depth estimation[D]. Xi’an: Northwestern Polytechnical University, 2014.
肖照林. 基于相机阵列的光场成像与深度估计方法研究[D]. 西安: 西北工业大学, 2014.
 Wilburn B, Joshi N, Vaish V, et al. High performance imaging using large camera arrays[J]. ACM Transactions on Graphics, 2005, 24(3): 765–776.
 Lumsdaine A, Georgiev T. The focused plenoptic camera[C]//Proceedings of 2009 IEEE International Conference on Computational Photography, 2009: 1–8.
 Wang L J, Zhang J, Zhang X D, et al. Micro-lens array center calibration via local searching using Lytro cameras[J]. Opto-Electronic Engineering, 2016, 43(11): 19–25.
王丽娟, 张骏, 张旭东, 等. 局部搜索式的Lytro相机微透镜阵列中心标定[J]. 光电工程, 2016, 43(11): 19–25.
 Veeraraghavan A, Raskar R, Agrawal A, et al. Dappled photography: mask enhanced cameras for heterodyned light fields and coded aperture refocusing[J]. ACM Transactions on Graphics, 2007, 26(3): 69.
 Green P, Sun W Y, Matusik W, et al. Multi-aperture photography[J]. ACM Transactions on Graphics, 2007, 26(3): 68.
 Zhang C P, Wang Q. Survey on imaging model and calibration of light field camera[J]. Chinese Journal of Lasers, 2016, 43(6): 0609004.
张春萍, 王庆. 光场相机成像模型及参数标定方法综述[J]. 中国激光, 2016, 43(6): 0609004.
 Wang Y Q, Yang J G, Guo Y L, et al. Selective light field refocusing for camera arrays using bokeh rendering and superresolution[J]. IEEE Signal Processing Letters, 2019, 26(1): 204–208.
 Shi M D, Zhang X D, Dong Y L, et al. A light field demosaicing method with double guided filtering[J]. Opto-Electronic Engineering, 2019, 46(12): 180539.
石梦迪, 张旭东, 董运流, 等. 一种双引导滤波的光场去马赛克方法[J]. 光电工程, 2019, 46(12): 180539.
“the 2020 Connotation Development Funds for Interdisciplinary Academic Construction” of Graduate School of Capital Normal University
Get Citation: Yang Moxuan, Zhao Yuanmeng, Zuo Jian, et al. An experimental study on terahertz light field data acquisition and digital refocusing[J]. Opto-Electronic Engineering, 2020, 47(5): 190670.