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 01, 2020
1 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.
2 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.
3 Gershun A. The light field[J]. Journal of Mathematics and Physics, 1939, 18(1-4): 51-151. DOI:10.1002/sapm193918151
4 Gabor D. A new microscopic principle[J]. Nature, 1948, 161(4098): 777-778. DOI:10.1038/161777a0
5 Levoy M, Hanrahan P. Light field rendering[C]//Proceedings of the 23rd Annual Conference on Computer Graphics and Interactive Techniques, 1996: 31-42.
6 Zhao G Z. Progress on terahertz science and technology[J]. Foreign Electronic Measurement Technology, 2014, 33(2): 1-6, 20. DOI:10.3969/j.issn.1002-8978.2014.02.001
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. DOI:10.3969/j.issn.1002-8978.2014.02.001
7 Hu B B, Nuss M C. Imaging with terahertz waves[J]. Optics Letters, 1995, 20(16): 1716-1718. DOI:10.1364/OL.20.001716
8 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. DOI:10.1063/1.4826456
9 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.
10 Jain R, Grzyb J, Pfeiffer U R. Terahertz light-field imaging[J]. IEEE Transactions on Terahertz Science and Technology, 2016, 6(5): 649-657.
11 Xiao Z L. Camera array based light field imaging and depth estimation[D]. Xi'an: Northwestern Polytechnical University, 2014.
12 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. DOI:10.1145/1073204.1073259
13 Lumsdaine A, Georgiev T. The focused plenoptic camera[C]//Proceedings of 2009 IEEE International Conference on Computational Photography, 2009: 1-8.
14 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. DOI:10.3969/j.issn.1003-501X.2016.11.004
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. DOI:10.3969/j.issn.1003-501X.2016.11.004
15 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. DOI:10.1145/1276377.1276463
16 Green P, Sun W Y, Matusik W, et al. Multi-aperture photography[J]. ACM Transactions on Graphics, 2007, 26(3): 68. DOI:10.1145/1276377.1276462
17 Zhang C P, Wang Q. Survey on imaging model and calibration of light field camera[J]. Chinese Journal of Lasers, 2016, 43(6): 0609004.
18 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. DOI:10.1109/LSP.2018.2885213
19 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. DOI:10.12086/oee.2019.180539
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. DOI:10.12086/oee.2019.180539
Supported by "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.