A new approach for image reconstruction in THz computed tomography (THz-CT) is presented. Based on a geometrical optics model containing the THz signal amplitude and phase, a novel algorithm for extracting an average phase from the measured THz signals is derived. Applying the algorithm results in a phase-contrast sinogram, which is further used for image reconstruction. For experimental validation, a fast THz time-domain spectrometer (THz-TDS) in transmission geometry is employed, enabling CT measurements within several minutes. Quantitative evaluation of reconstructed 3D printed plastic profiles reveals the potential of our approach in non-destructive testing of plastic profiles.
@article{arxiv.2102.08650,
title = {Phase-contrast THz-CT for non-destructive testing},
author = {Peter Fosodeder and Simon Hubmer and Alexander Ploier and Ronny Ramlau and Sandrine van Frank and Christian Rankl},
journal= {arXiv preprint arXiv:2102.08650},
year = {2021}
}