Non-mydriatic confocal retinal imaging using a digital light projector

Muller, Matthew S.; Green, Jason J; Baskaran, Karthikeyan; Ingling, Allen W; Clendenon, Jeffrey L.; Gast, Thomas; Elsner, Ann E.

doi:10.1117/12.2077704

Cited by 11 publications

(4 citation statements)

References 10 publications

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“…A digital micromirror device (DMD) is a spatial light modulator consisting of a 2D micromirror array for which the mirror elements can be individually controlled to create specific illumination patterns. The use of the DMD has been demonstrated for ophthalmic imaging to create an LSO by rapidly projecting a single line to the retina and recording the back-scattered light with a rolling shutter camera [5]. Combining the DMD with a high-speed full-field camera will provide further speed improvements.…”

Section: Introductionmentioning

confidence: 99%

Parallel line scanning ophthalmoscope for retinal imaging

Vienola¹,

Damodaran²,

Braaf³

et al. 2015

Opt. Lett.

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Section: Introductionmentioning

confidence: 99%

Parallel line scanning ophthalmoscope for retinal imaging

Vienola¹,

Damodaran²,

Braaf³

et al. 2015

Opt. Lett.

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“…The USB port of the camera was utilized for driving the camera. According to the previous research [6], the width of the camera's shutter was set as three times bigger than the width of the illumination lines. In the second phase of research by using this confocal microscope setup a dataset was prepared to apply its contrast enhancement to any other low-contrast image to obtain high quality outputs (Fig.…”

Section: Development Of Line-scanning Confocal Microscopementioning

confidence: 99%

Contrast improvement through a Generative Adversarial Network (GAN) by utilizing a dataset obtained from a line-scanning confocal microscope.

Ketabchi,

Morova,

Bavili

et al. 2024

Optics, Photonics, and Digital Technologies for Imaging Applications VIII

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Confocal microscopy offers enhanced image contrast and signal-to-noise ratio compared to wide-field illumination microscopy, achieved by effectively eliminating out-of-focus background noise. In our study, we initially showcase the functionality of a line-scanning confocal microscope aligned through the utilization of a Digital Light Projector (DLP) and a rolling shutter CMOS camera. In this technique, a sequence of illumination lines is projected onto a sample using a DLP and focusing objective (50X, NA=0.55). The reflected light is imaged with the camera. Line-scanning confocal imaging is accomplished by synchronizing the illumination lines with the rolling shutter of the sensor, leading to a substantial enhancement of approximately 50% in image contrast. Subsequently, this setup is employed to create a dataset comprising 500 pairs of images of paper tissue. This dataset is employed for training a Generative Adversarial Network (cGAN). Roughly 45% contrast improvement was measured in the test images for the trained network, in comparison to the ground-truth images.

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“…The uniaxial design in conjunction with the compact DMD makes it possible to avoid the use of larger translational or rotational components throughout the system thereby enhancing accuracy. Recent studies in retinal imaging have also used DMDs as integrated illumination and scanning elements for confocal imaging and single pixel imaging in ophthalmoscopes.…”

Section: Introductionmentioning

confidence: 99%

Analysing the impact of myopia on the Stiles‐Crawford effect of the first kind using a digital micromirror device

Martins

Vohnsen

2018

Ophthalmic Physiologic Optic

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Purpose Photoreceptor light acceptance is closely tied to the Stiles‐Crawford effect of the first kind (SCE‐I). Whether the SCE‐I plays a role in myopic development remains unclear although a reduction in directionality has been predicted for high myopia. The purpose of this study is to analyse the relationship between foveal SCE‐I directionality, axial eye length, and defocus for emmetropic subjects wearing ophthalmic trial lenses during psychophysical measurements and for myopic subjects with their natural correction. Method A novel uniaxial flicker system has been implemented making use of a Digital Micromirror Device (DMD) to flicker between a 2.3 visual degrees circular reference and a set of circular test patterns in a monocular Maxwellian view at 0.5 Hz. The brightness of the test is adjusted by the duty cycle of the projected light to an upper limit of 22 727 Hz. The wavelength and bandwidth are set by a tuneable liquid‐crystal filter centred at 550 nm. A total of four measurement series for 11 pupil entrance points have been realized for the right eye of 6 emmetropic and 10 myopic subjects whose pupils were dilated with tropicamide. Five of the emmetropic subjects wore ophthalmic trial lenses in the range of −3 to +9 dioptres to mimic hyperopic to highly myopic vision and resulting visibility plots have been fitted to a Gaussian SCE‐I function. In turn, the myopic subjects wore their natural correction during the analysis of the SCE‐I. All subjects had their axial eye length determined with an ultrasound device. Results A SCE‐I directionality parameter in the range of 0.03 to 0.06/mm2 was found for the emmetropic subjects with corrected vision in fair agreement to values in the literature. The results also revealed a marked reduction in directionality in the range from 16% to 30% with every 3 dioptre increase of simulated myopia, as well as a 10% increased directionality in simulated hyperopic eyes. For both emmetropic and myopic subjects, a decrease in directionality with increase in axial length was found in agreement with theoretical expectations. Conclusion The study confirms a clear link between SCE‐I directionality, uncorrected defocus, and axial eye length. This may play a role for emmetropization and thus myopic progression as cone photoreceptors capture light from a wider pupil area in elongated eyes due to a geometrical scaling.

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Non-mydriatic confocal retinal imaging using a digital light projector

Cited by 11 publications

References 10 publications

Parallel line scanning ophthalmoscope for retinal imaging

Parallel line scanning ophthalmoscope for retinal imaging

Contrast improvement through a Generative Adversarial Network (GAN) by utilizing a dataset obtained from a line-scanning confocal microscope.

Analysing the impact of myopia on the Stiles‐Crawford effect of the first kind using a digital micromirror device

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