J-Net: Improved U-Net for Terahertz Image Super-Resolution

Terahertz (THz) waves are electromagnetic waves in the 0.1 to 10 THz frequency range, and THz imaging is utilized in a range of applications, including security inspections, biomedical fields, and the non-destructive examination of materials. However, THz images have low resolution due to the long wavelength of THz waves. Therefore, improving the resolution of THz images is one of the current hot research topics. We propose a novel network architecture called J-Net which is improved version of U-Net to solve the THz image super-resolution. It employs the simple baseline blocks which can extract low resolution (LR) image features and learn the mapping of LR images to highresolution (HR) images efficiently. All training was conducted using the DIV2K+Flickr2K dataset, and we employed the peak signal-to-noise ratio (PSNR) for quantitative comparison. In our comparisons with other THz image super-resolution methods, JNet achieved a PSNR of 32.52 dB, surpassing other techniques by more than 1 dB. J-Net also demonstrates superior performance on real THz images compared to other methods. Experiments show that the proposed J-Net achieves better PSNR and visual improvement compared with other THz image super-resolution methods.