Resolution enhancement in compressive-sensing-based terahertz time-domain imaging

Terahertz (THz) time-domain spectroscopy (THz-TDS) imaging provides both spatial and spectral information of materials but suffers from limited resolution at low frequencies. In this work, we investigate the resolution enhancement of THz-TDS images that are reconstructed using Compressed sensing from under-sampled measurements, using three complementary approaches: sparse representation, Wiener filtering, and low-rank representation. The proposed methods are validated on experimentally acquired THz-TDS datasets, including a resolution chart and a printed circuit board. The results demonstrate that all three methods enhance resolution. In particular, sparse representation and wiener filter better preserve contrast between different materials, whereas low-rank representation reveals finer structural details. These findings highlight the effectiveness of combining compressed sensing with post-reconstruction resolution enhancement, providing a practical pathway toward fast, high-resolution THz imaging.