Super-resolution of THz time-domain images based on low-rank
  representation
Marina Ljubenovic Alessia Artesani Stefano Bonetti Arianna Traviglia
Terahertz time-domain spectroscopy (THz-TDS) employs sub-picosecond pulses to
probe dielectric properties of materials giving as a result a 3-dimensional
hyperspectral data cube. The spatial resolution of THz images is primarily
limited by two sources: a non-zero THz beam waist and the acquisition step
size. Acquisition with a small step size allows for the visualisation of
smaller details in images at the expense of acquisition time, but the
frequency-dependent point-spread function remains the biggest bottleneck for
THz imaging. This work presents a super-resolution approach to restore THz
time-domain images acquired with medium-to-big step sizes. The results show the
optimized and robust performance for different frequency bands (from 0.5 to 3.5
THz) obtaining higher resolution and additionally removing effects of blur at
lower frequencies and noise at higher frequencies.