Calibration Alignment Sensitivity in Corneal Terahertz Imaging
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2022-05-01
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Language
en
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Sensors, Volume 22, issue 9
Abstract
Improving the longitudinal modes coupling in layered spherical structure contributes significantly to corneal terahertz sensing, which plays a crucial role in the early diagnosis of cornea dystrophies. Using a steel sphere to calibrate reflection from the cornea sample assists in enhancing the resolution of longitudinal modes. The requirement and challenges toward applying the calibration sphere are introduced and addressed. Six corneas with different properties are spotted to study the effect of perturbations in the calibration sphere in a frequency range from 100 GHz to 600 GHz. A particle-swarm optimization algorithm is employed to quantify corneal characteristics considering cases of accurately calibrated and perturbed calibrated scenarios. For the first case, the study is carried out with signal-to-noise values of 40 dB, 50 dB and 60 dB at waveguide bands WR-5.1, WR-3.4, and WR-2.2. As expected, better estimation is achieved in high-SNR cases. Furthermore, the lower waveguide band is revealed as the mostproper band for the assessment of corneal features. For perturbed cases, the analysis is continued for the noise level of 60 dB in the three waveguide bands. Consequently, the error in the estimation of corneal properties rises significantly (around 30%).Description
Funding Information: Funding: This research was funded by the Agencia Estatal de Investigación PID2019-107885GB-C31/AEI/10.13039, PRE2018-084326, and Academy of Finland Project number 327640. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
Keywords
cornea, particle-swarm optimization, terahertz
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Citation
Zarrinkhat , F , Baggio , M , Lamberg , J , Tamminen , A , Nefedova , I , Ala-Laurinaho , J , Khaled , E E M , Rius , J M , Romeu , J & Taylor , Z 2022 , ' Calibration Alignment Sensitivity in Corneal Terahertz Imaging ' , Sensors , vol. 22 , no. 9 , 3237 . https://doi.org/10.3390/s22093237
