Abstract:The frequency of terahertz wave is between infrared ray and microwave, and its unique advantages make terahertz three-dimensional imaging become a research hotspot at home and abroad. In order to extend the optical field imaging technology to terahertz band, the experiments and processing methods of terahertz optical field imaging are introduced. A series of terahertz optical field data with specific viewing angles are collected using a terahertz camera array. Device limitations of the imaging system cause noise in images. Aiming at this problem, discrete cosine transform filtering achieves a good denoising effect and effectively retains the details of the images. Peak signal-to-noise ratio and structural similarity are used to compare various filtering denoising methods, which proves the feasibility of DCT filtering method in terahertz image preprocessing. The digital refocusing of terahertz optical field imaging is realized preliminarily by selecting different depth values to reconstruct images in different depths.