Published In
Sensors
Document Type
Article
Publication Date
2018
Subjects
Pattern recognition systems, Tomography--Technological innovations
Abstract
Terahertz (THz) time of flight (TOF) tomography systems offer a new measurement modality for non-destructive evaluation (NDE) of the subsurface layers of protective coatings and/or laminated composite materials for industrial, security and biomedical applications. However, for thin film samples, the time-of-flight within a layer is less than the duration of the THz pulse and consequently there is insufficient range resolution for NDE of the sample under test. In this paper, matched field processing (MFP) techniques are applied to thickness estimation in THz TOF tomography applications, and these methods are demonstrated by using measured THz spectra to estimate the the thicknesses of a thin air gap and its depth below the surface. MFP methods have been developed over several decades in the underwater acoustics community for model-based inversion of geo-acoustic parameters. It is expected that this research will provide an important link for THz researchers to access and apply the robust methods available in the MFP literature.
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DOI
10.3390/s18103547
Persistent Identifier
https://archives.pdx.edu/ds/psu/26445
Citation Details
Schecklman, S., & Zurk, L. (2018). Terahertz Imaging of Thin Film Layers with Matched Field Processing. Sensors, 18(10), 3547.
Description
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).