Terahertz time-gated spectral imaging for content extraction through layered structures
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Terahertz time-gated.pdf
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Author(s) • • • • • •
Aghasi, Alireza
Romberg, Justin
Redo-Sanchez, Albert
Heshmat Dehkordi, Barmak
Naqvi, Salman
Zhang, Mingjie
Raskar, Ramesh
Date Issued
September 2016
Journal
Nature Communications
Publisher
Nature Publishing Group
Citation
Redo-Sanchez, Albert et al. “Terahertz Time-Gated Spectral Imaging for Content Extraction through Layered Structures.” Nature Communications 7 (2016): 12665.
Version
Final published version
Abstract
Spatial resolution, spectral contrast and occlusion are three major bottlenecks for non-invasive inspection of complex samples with current imaging technologies. We exploit the sub-picosecond time resolution along with spectral resolution provided by terahertz time-domain spectroscopy to computationally extract occluding content from layers whose thicknesses are wavelength comparable. The method uses the statistics of the reflected terahertz electric field at subwavelength gaps to lock into each layer position and then uses a time-gated spectral kurtosis to tune to highest spectral contrast of the content on that specific layer. To demonstrate, occluding textual content was successfully extracted from a packed stack of paper pages down to nine pages without human supervision. The method provides over an order of magnitude enhancement in the signal contrast and can impact inspection of structural defects in wooden objects, plastic components, composites, drugs and especially cultural artefacts with subwavelength or wavelength comparable layers.
MIT Department
Massachusetts Institute of Technology. Media Laboratory
Program in Media Arts and Sciences (Massachusetts Institute of Technology)
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Creative Commons Attribution 4.0 International License
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DOI of Published Version
https://doi.org/10.1038/ncomms12665