Calibration Alignment Sensitivity in Corneal Terahertz Imaging
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 resol...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-04-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/22/9/3237 |
| _version_ | 1797502919782694912 |
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| author | Faezeh Zarrinkhat Mariangela Baggio Joel Lamberg Aleksi Tamminen Irina Nefedova Juha Ala-Laurinaho Elsayed E. M. Khaled Juan M. Rius Jordi Romeu Zachary Taylor |
| author_facet | Faezeh Zarrinkhat Mariangela Baggio Joel Lamberg Aleksi Tamminen Irina Nefedova Juha Ala-Laurinaho Elsayed E. M. Khaled Juan M. Rius Jordi Romeu Zachary Taylor |
| author_sort | Faezeh Zarrinkhat |
| collection | DOAJ |
| description | 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-<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>5.1</mn></mrow></semantics></math></inline-formula>, WR-<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>3.4</mn></mrow></semantics></math></inline-formula>, and WR-<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.2</mn></mrow></semantics></math></inline-formula>. As expected, better estimation is achieved in high-SNR cases. Furthermore, the lower waveguide band is revealed as the most proper 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 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>30</mn><mo>%</mo></mrow></semantics></math></inline-formula>). |
| first_indexed | 2024-03-10T03:43:03Z |
| format | Article |
| id | doaj.art-74923ae3dc9a4dd0b35509de2bb52aef |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-10T03:43:03Z |
| publishDate | 2022-04-01 |
| publisher | MDPI AG |
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| series | Sensors |
| spelling | doaj.art-74923ae3dc9a4dd0b35509de2bb52aef2023-11-23T09:15:27ZengMDPI AGSensors1424-82202022-04-01229323710.3390/s22093237Calibration Alignment Sensitivity in Corneal Terahertz ImagingFaezeh Zarrinkhat0Mariangela Baggio1Joel Lamberg2Aleksi Tamminen3Irina Nefedova4Juha Ala-Laurinaho5Elsayed E. M. Khaled6Juan M. Rius7Jordi Romeu8Zachary Taylor9CommSensLab, Technical University of Catalonia/UPC, 08034 Barcelona, SpainDepartment of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, FinlandDepartment of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, FinlandDepartment of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, FinlandDepartment of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, FinlandDepartment of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, FinlandDepartment of Electrical Engineering, Assiut University, Assiut 71515, EgyptCommSensLab, Technical University of Catalonia/UPC, 08034 Barcelona, SpainCommSensLab, Technical University of Catalonia/UPC, 08034 Barcelona, SpainDepartment of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, FinlandImproving 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-<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>5.1</mn></mrow></semantics></math></inline-formula>, WR-<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>3.4</mn></mrow></semantics></math></inline-formula>, and WR-<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.2</mn></mrow></semantics></math></inline-formula>. As expected, better estimation is achieved in high-SNR cases. Furthermore, the lower waveguide band is revealed as the most proper 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 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>30</mn><mo>%</mo></mrow></semantics></math></inline-formula>).https://www.mdpi.com/1424-8220/22/9/3237corneaparticle-swarm optimizationterahertz |
| spellingShingle | Faezeh Zarrinkhat Mariangela Baggio Joel Lamberg Aleksi Tamminen Irina Nefedova Juha Ala-Laurinaho Elsayed E. M. Khaled Juan M. Rius Jordi Romeu Zachary Taylor Calibration Alignment Sensitivity in Corneal Terahertz Imaging Sensors cornea particle-swarm optimization terahertz |
| title | Calibration Alignment Sensitivity in Corneal Terahertz Imaging |
| title_full | Calibration Alignment Sensitivity in Corneal Terahertz Imaging |
| title_fullStr | Calibration Alignment Sensitivity in Corneal Terahertz Imaging |
| title_full_unstemmed | Calibration Alignment Sensitivity in Corneal Terahertz Imaging |
| title_short | Calibration Alignment Sensitivity in Corneal Terahertz Imaging |
| title_sort | calibration alignment sensitivity in corneal terahertz imaging |
| topic | cornea particle-swarm optimization terahertz |
| url | https://www.mdpi.com/1424-8220/22/9/3237 |
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