Submillimeter-wave imaging assisted alignment of millimeter-wave spectroscopic system for quantification of corneal water content

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Conference article in proceedings
Date
2020-01-01
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Language
en
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SPIE Conference Proceedings, Proceedings of SPIE : the International Society for Optical Engineering, Volume 11348
Abstract
We propose an alignment strategy for millimeter spectroscopy of cornea that uses imaging to screen for sufficient alignment conditions. The performance of different corneal imaging objectives, in the presence of misalignment, is evaluated. The cornea is illuminated with a TEM00 Gaussian beam at 650 GHz and the beam is swept across the cornea. Images are generated by calculating the coupling between illumination and scattered beams for each illumination beam position and angle. The cornea is displaced at intervals of 500 microns in the transverse and axial directions and with new coupling coefficient maps generated at each misaligned position. Contrast in the misaligned cases are compared to the aligned case via zero normalized spatial cross correlation. The results show a maximum normalized cross correlation of 0.92 for a two-mirror scanning system and 0.74 for a one-mirror scanning objective. The analysis suggests that imaging contrast at 650 GHz can be used to screen for misalignment that would be difficultto detect with MMW.
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Keywords
Cornea, medical imaging, physical optics, quasioptics, submillimeter wave remote sensing, THz, THz imaging
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Citation
Baggio , M , Hu , Y , Tamminen , A , Nefedova , I , Ala-Laurinaho , J & Taylor , Z 2020 , Submillimeter-wave imaging assisted alignment of millimeter-wave spectroscopic system for quantification of corneal water content . in M Jarrahi , S Preu & D Turchinovich (eds) , SPIE Conference Proceedings . , 113480M , Proceedings of SPIE : the International Society for Optical Engineering , vol. 11348 , SPIE , SPIE Photonics Europe , Virtual, Online , France , 06/04/2020 . https://doi.org/10.1117/12.2556309