| Citation: | XIN Tao, PENG Shuo, DONG Li-quan, ZHANG Shao-hui, ZHANG Cun-lin. Improving terahertz imaging by light field processing[J]. Chinese Optics, 2022, 15(6): 1313-1320. doi: 10.37188/CO.EN.2022-0005
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Terahertz (THz) technology becomes increasingly important nowadays, especially in testing and security applications. Extending the field of view and increasing the imaging quality are both vital challenges for THz imaging. To address these problems, we build a THz light field imaging system based on a single-camera scanning configuration, which utilizes the 4D information of the spatial and angular distribution of THz waves. Based on the 4D plenoptic function and the parameterization method with two parallel planes, the intensity consistency of THz propagation is used for refocusing calculation, then a series of refocused images can be obtained by integrating original light field images corresponding to different imaging distances and views. Compared with the original THz imaging, the field of view and the imaging quality of the THz light field imaging are effectively improved. In our experiment, the field of view was enlarged by a factor of 1.84 and the resolution increased from 1.3 mm to 0.7 mm. Furthermore, information on some obscured targets could also be retrieved by defocusing the obstructions. This method could improve the imaging quality of THz imaging as well as expand its functions, which inspires a new way for THz nondestructive testing (NDT) and security inspection.
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