Open AccessCo-registered combined OCT and THz imaging to extract depth and refractive index of a tissue-equivalent test object
Author(s) -
Anthony J. Fitzgerald,
Xin Tie,
Michael J. Hackmann,
Barry Cense,
Adam Gibson,
Vincent P. Wallace
Publication year - 2020
Publication title -
biomedical optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.362
H-Index - 86
ISSN - 2156-7085
DOI - 10.1364/boe.378506
Subject(s) - optical coherence tomography , terahertz radiation , refractive index , optics , medical imaging , computer science , terahertz spectroscopy and technology , materials science , biomedical engineering , artificial intelligence , physics , medicine
Terahertz (THz) imaging and optical coherence tomography (OCT) provide complementary information with similar length scales. In addition to OCT's extensive use in ophthalmology, both methods have shown some promise for other medical applications and non-destructive testing. In this paper, we present an iterative algorithm that combines the information from OCT and THz imaging at two different measurement locations within an object to determine both the depth of the reflecting layers at the two locations and the unknown refractive index of the medium for both the OCT wavelengths and THz frequencies. We validate this algorithm using a silicone test object with embedded layers and show that the depths and refractive index values obtained from the algorithm agreed with the measured values to within 3.3%. We further demonstrate for the first time that OCT and THz images can be co-registered and aligned using unsupervised image registration. Hence we show that a combined OCT/THz system can provide unique information beyond the capability of the separate modalities alone, with possible applications in the medical, industrial and pharmaceutical sectors.