Normalization of Retinal Birefringence Scanning Signals
Signal amplitudes obtained from retinal scanning depend on numerous factors. Working with polarized light to interrogate the retina, large parts of which are birefringent, is even more prone to artifacts. This article demonstrates the necessity of using normalization when working with retinal birefr...
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MDPI AG
2024-12-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/25/1/165 |
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| author | Boris I. Gramatikov David L. Guyton |
| author_facet | Boris I. Gramatikov David L. Guyton |
| author_sort | Boris I. Gramatikov |
| collection | DOAJ |
| description | Signal amplitudes obtained from retinal scanning depend on numerous factors. Working with polarized light to interrogate the retina, large parts of which are birefringent, is even more prone to artifacts. This article demonstrates the necessity of using normalization when working with retinal birefringence scanning signals in polarization-sensitive ophthalmic instruments. After discussing the pros and cons of employing a normalization signal obtained by means of added optoelectronic hardware, the study shifts over and focuses on a numerical normalization method based on merely the <i>s</i>- and <i>p</i>-polarization components without additional optical or electronic hardware. This minimizes the adverse effects of optical asymmetries, the presence of certain instrumental noise, device-to-device variability, pupil diameter, retinal reflectivity, subject-to-subject variations, the position of the eye in the exit pupil of the device, and even signal degradation by cataracts. Results were experimentally and numerically tested on human data from 15 test subjects and clearly demonstrated the signal standardization achieved by numerical normalization. This is expected to lead to substantial improvement in algorithms and decision-making software, especially in ophthalmic screening instruments for pediatric applications, without added hardware cost. The proposed normalization method is also applicable to other polarization-sensitive optical instruments. |
| format | Article |
| id | doaj-art-ef2fac1b54744aaa8be9778fc04731c4 |
| institution | Kabale University |
| issn | 1424-8220 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj-art-ef2fac1b54744aaa8be9778fc04731c42025-01-10T13:21:05ZengMDPI AGSensors1424-82202024-12-0125116510.3390/s25010165Normalization of Retinal Birefringence Scanning SignalsBoris I. Gramatikov0David L. Guyton1Ophthalmic Instrumentation Development Lab, The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Wilmer 233, 600 N. Wolfe St., Baltimore, MD 21287, USAOphthalmic Instrumentation Development Lab, The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Wilmer 233, 600 N. Wolfe St., Baltimore, MD 21287, USASignal amplitudes obtained from retinal scanning depend on numerous factors. Working with polarized light to interrogate the retina, large parts of which are birefringent, is even more prone to artifacts. This article demonstrates the necessity of using normalization when working with retinal birefringence scanning signals in polarization-sensitive ophthalmic instruments. After discussing the pros and cons of employing a normalization signal obtained by means of added optoelectronic hardware, the study shifts over and focuses on a numerical normalization method based on merely the <i>s</i>- and <i>p</i>-polarization components without additional optical or electronic hardware. This minimizes the adverse effects of optical asymmetries, the presence of certain instrumental noise, device-to-device variability, pupil diameter, retinal reflectivity, subject-to-subject variations, the position of the eye in the exit pupil of the device, and even signal degradation by cataracts. Results were experimentally and numerically tested on human data from 15 test subjects and clearly demonstrated the signal standardization achieved by numerical normalization. This is expected to lead to substantial improvement in algorithms and decision-making software, especially in ophthalmic screening instruments for pediatric applications, without added hardware cost. The proposed normalization method is also applicable to other polarization-sensitive optical instruments.https://www.mdpi.com/1424-8220/25/1/165retinal birefringence scanningpolarization-sensitive systemsophthalmic screening devicessignal normalization |
| spellingShingle | Boris I. Gramatikov David L. Guyton Normalization of Retinal Birefringence Scanning Signals Sensors retinal birefringence scanning polarization-sensitive systems ophthalmic screening devices signal normalization |
| title | Normalization of Retinal Birefringence Scanning Signals |
| title_full | Normalization of Retinal Birefringence Scanning Signals |
| title_fullStr | Normalization of Retinal Birefringence Scanning Signals |
| title_full_unstemmed | Normalization of Retinal Birefringence Scanning Signals |
| title_short | Normalization of Retinal Birefringence Scanning Signals |
| title_sort | normalization of retinal birefringence scanning signals |
| topic | retinal birefringence scanning polarization-sensitive systems ophthalmic screening devices signal normalization |
| url | https://www.mdpi.com/1424-8220/25/1/165 |
| work_keys_str_mv | AT borisigramatikov normalizationofretinalbirefringencescanningsignals AT davidlguyton normalizationofretinalbirefringencescanningsignals |