650 GHz Imaging as Alignment Verification for Millimeter Wave Corneal Reflectometry

Yong Hu; Mariangela Baggio; Shahab Oddin Dabironezare; Aleksi Tamminen; Brandon Toy; Juha Ala-Laurinaho; Elliott R. Brown; Nuria Llombart; Sophie X. Deng; Vincent P. Wallace; Zachary D. Taylor

doi:10.1109/TTHZ.2021.3140199

650 GHz Imaging as Alignment Verification for Millimeter Wave Corneal Reflectometry

Yong Hu, Mariangela Baggio, Shahab Oddin Dabironezare, Aleksi Tamminen, Brandon Toy, Juha Ala-Laurinaho, Elliott R. Brown, Nuria Llombart, Sophie X. Deng, Vincent P. Wallace, Zachary D. Taylor

Physics

Research output: Contribution to journal › Article › peer-review

5 Citations (Scopus)

Abstract

A system concept for online alignment verification of millimeter-wave, corneal reflectometry is presented. The system utilizes beam scanning to generate magnitude-only reflectivity maps of the cornea at 650 GHz and compares these images to a precomputed/measured template map to confirm/reject sufficient alignment. A system utilizing five off-axis parabolic mirrors, a thin film beam splitter, and two-axis galvanometric mirror was designed, simulated, and evaluated with geometric and physical optics. Simulation results informed the construction of a demonstrator system which was tested with a reference reflector. Similarity metrics computed with the aligned template and 26 misaligned positions, distributed on a 0.5 mm x 0.5 mm x 0.5 mm mesh, demonstrated sufficient misalignment detection sensitivity in 23 out of 26 positions. The results show that positional accuracy on the order of 0.5 mm is possible using 0.462 mm wavelength radiation due to the perturbation of coupling efficiency via beam distortion and beam walk-off.

Original language	English
Pages (from-to)	151-164
Number of pages	14
Journal	IEEE Transactions on Terahertz Science and Technology
Volume	12
Issue number	2
DOIs	https://doi.org/10.1109/TTHZ.2021.3140199
Publication status	Published - 1 Mar 2022

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@article{15722409e5124a648fa56569987a9dc3,

title = "650 GHz Imaging as Alignment Verification for Millimeter Wave Corneal Reflectometry",

abstract = "A system concept for online alignment verification of millimeter-wave, corneal reflectometry is presented. The system utilizes beam scanning to generate magnitude-only reflectivity maps of the cornea at 650 GHz and compares these images to a precomputed/measured template map to confirm/reject sufficient alignment. A system utilizing five off-axis parabolic mirrors, a thin film beam splitter, and two-axis galvanometric mirror was designed, simulated, and evaluated with geometric and physical optics. Simulation results informed the construction of a demonstrator system which was tested with a reference reflector. Similarity metrics computed with the aligned template and 26 misaligned positions, distributed on a 0.5 mm x 0.5 mm x 0.5 mm mesh, demonstrated sufficient misalignment detection sensitivity in 23 out of 26 positions. The results show that positional accuracy on the order of 0.5 mm is possible using 0.462 mm wavelength radiation due to the perturbation of coupling efficiency via beam distortion and beam walk-off. ",

keywords = "Biological and medical imaging, Clinical instruments, Medical diagnostics, THz imaging of cornea",

author = "Yong Hu and Mariangela Baggio and Dabironezare, {Shahab Oddin} and Aleksi Tamminen and Brandon Toy and Juha Ala-Laurinaho and Brown, {Elliott R.} and Nuria Llombart and Deng, {Sophie X.} and Wallace, {Vincent P.} and Taylor, {Zachary D.}",

year = "2022",

month = mar,

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doi = "10.1109/TTHZ.2021.3140199",

language = "English",

volume = "12",

pages = "151--164",

journal = "IEEE Transactions on Terahertz Science and Technology",

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T1 - 650 GHz Imaging as Alignment Verification for Millimeter Wave Corneal Reflectometry

AU - Hu, Yong

AU - Baggio, Mariangela

AU - Dabironezare, Shahab Oddin

AU - Tamminen, Aleksi

AU - Toy, Brandon

AU - Ala-Laurinaho, Juha

AU - Brown, Elliott R.

AU - Llombart, Nuria

AU - Deng, Sophie X.

AU - Wallace, Vincent P.

AU - Taylor, Zachary D.

PY - 2022/3/1

Y1 - 2022/3/1

N2 - A system concept for online alignment verification of millimeter-wave, corneal reflectometry is presented. The system utilizes beam scanning to generate magnitude-only reflectivity maps of the cornea at 650 GHz and compares these images to a precomputed/measured template map to confirm/reject sufficient alignment. A system utilizing five off-axis parabolic mirrors, a thin film beam splitter, and two-axis galvanometric mirror was designed, simulated, and evaluated with geometric and physical optics. Simulation results informed the construction of a demonstrator system which was tested with a reference reflector. Similarity metrics computed with the aligned template and 26 misaligned positions, distributed on a 0.5 mm x 0.5 mm x 0.5 mm mesh, demonstrated sufficient misalignment detection sensitivity in 23 out of 26 positions. The results show that positional accuracy on the order of 0.5 mm is possible using 0.462 mm wavelength radiation due to the perturbation of coupling efficiency via beam distortion and beam walk-off.

AB - A system concept for online alignment verification of millimeter-wave, corneal reflectometry is presented. The system utilizes beam scanning to generate magnitude-only reflectivity maps of the cornea at 650 GHz and compares these images to a precomputed/measured template map to confirm/reject sufficient alignment. A system utilizing five off-axis parabolic mirrors, a thin film beam splitter, and two-axis galvanometric mirror was designed, simulated, and evaluated with geometric and physical optics. Simulation results informed the construction of a demonstrator system which was tested with a reference reflector. Similarity metrics computed with the aligned template and 26 misaligned positions, distributed on a 0.5 mm x 0.5 mm x 0.5 mm mesh, demonstrated sufficient misalignment detection sensitivity in 23 out of 26 positions. The results show that positional accuracy on the order of 0.5 mm is possible using 0.462 mm wavelength radiation due to the perturbation of coupling efficiency via beam distortion and beam walk-off.

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KW - Clinical instruments

KW - Medical diagnostics

KW - THz imaging of cornea

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JO - IEEE Transactions on Terahertz Science and Technology

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650 GHz Imaging as Alignment Verification for Millimeter Wave Corneal Reflectometry

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