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The technique of remote refocusing is used in optical microscopy to provide rapid axial scanning without mechanically perturbing the sample and in techniques such as oblique plane microscopy that build on remote refocusing to image a tilted…

Optics · Physics 2023-09-27 Wenzhi Hong , Hugh Sparks , Chris Dunsby

Optical metasurfaces have been extensively investigated, demonstrating diverse and multiple functionalities with complete control over the transmitted and reflected fields. Most optical metasurfaces are however static, with only a few…

We present a new way to mitigate focal-ratio degradation (FRD) when using optical fibers to transport multimode light. Our approach exploits a custom multicore fiber (MCF) with six dissimilar cores that are single mode at ~1550 nm…

In principle, diffractive optics, particularly Phase Fresnel Lenses (PFLs), offer the ability to construct large, diffraction-limited, and highly efficient X-ray/$\gamma$-ray telescopes, leading to dramatic improvement in angular resolution…

Purpose: To evaluate nerve fiber layer (NFL) reflectance for glaucoma diagnosis. Methods: Participants were imaged with 4.5X4.5-mm volumetric disc scans using spectral-domain optical coherence tomography (OCT). The normalized NFL…

Image and Video Processing · Electrical Eng. & Systems 2020-06-25 Ou Tan , Liang Liu , Qisheng You , Jie Wang , Aiyin Chen , Eliesa Ing , John C. Morrison , Yali Jia , David Huang

Optical flow estimation is an important yet challenging problem in the field of video analytics. The features of different semantics levels/layers of a convolutional neural network can provide information of different granularity. To…

Computer Vision and Pattern Recognition · Computer Science 2021-11-24 Xiaolin Song , Yuyang Zhao , Jingyu Yang , Cuiling Lan , Wenjun Zeng

Refractive error, one of the leading cause of visual impairment, can be corrected by simple interventions like prescribing eyeglasses. We trained a deep learning algorithm to predict refractive error from the fundus photographs from…

Computer Vision and Pattern Recognition · Computer Science 2020-06-03 Avinash V. Varadarajan , Ryan Poplin , Katy Blumer , Christof Angermueller , Joe Ledsam , Reena Chopra , Pearse A. Keane , Greg S. Corrado , Lily Peng , Dale R. Webster

Optical imperfections, misalignments, aberrations, and even dust can significantly limit sensitivity in high-contrast imaging systems such as coronagraphs. An upstream deformable mirror (DM) in the pupil can be used to correct or compensate…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Johanan L. Codona , Matthew Kenworthy

Purpose: To investigate whether synthetically generated fractal data can be used to train deep learning (DL) models for dynamic MRI reconstruction, thereby avoiding the privacy, licensing, and availability limitations associated with…

Computer Vision and Pattern Recognition · Computer Science 2026-04-01 Anirudh Raman , Olivier Jaubert , Mark Wrobel , Tina Yao , Ruaraidh Campbell , Rebecca Baker , Ruta Virsinskaite , Daniel Knight , Michael Quail , Jennifer Steeden , Vivek Muthurangu

In this work it is shown that vascular structures of the human retina represent geometrical multifractals, characterized by a hierarchy of exponents rather then a single fractal dimension. A number of retinal images from the STARE database…

Biological Physics · Physics 2007-05-23 T. Stosic , B. Stosic

The construction of fractal generalized zone plates (FraGZPs) from a set of periodic diffractive optical elements with circular symmetry is proposed. This allows us to increase the number of foci of a conventional fractal zone plate…

The purpose of FFREE - the new optical bench devoted to experiments on high-contrast imaging at LAOG - consists in the validation of algorithms based on off-line calibration techniques and adaptive optics (AO) respectively for the wavefront…

Gravitational waves (GWs) exhibit wave-optics effects when their wavelength is comparable to the scale of the gravitational lens. This may occur in lensing from galactic subhalos in GWs emitted by binary black-hole mergers, and is gaining…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-16 Nino Ephremidze , Marc Kamionkowski , Cora Dvorkin

This paper presents the results of a Fresnel Interferometric Array testbed. This new concept of imager involves diffraction focussing by a thin foil, in which many thousands of punched subapertures form a pattern related to a Fresnel zone…

Astrophysics · Physics 2008-08-07 Denis Serre , Laurent Koechlin , Paul Deba

Direct imaging of exoplanets requires very high contrast levels, which are obtained using coronagraphs. But residual quasi-static aberrations create speckles in the focal plane downstream of the coronagraph which mask the planet. This…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 J. Mazoyer , P. Baudoz , R. Galicher , M. Mas , G. Rousset

The vascular structure in retinal images plays a crucial role in ophthalmic diagnostics, and its accuracies are directly influenced by the quality of the retinal image. Contrast enhancement is one of the crucial steps in any segmentation…

Computer Vision and Pattern Recognition · Computer Science 2025-04-22 Adnan Shaout , Jiho Han

The interstellar medium seems to have an underlying fractal structure which can be characterized through its fractal dimension. However, interstellar clouds are observed as projected two-dimensional images, and the projection of a…

Astrophysics · Physics 2007-05-23 Nestor Sanchez , Emilio J. Alfaro , Enrique Perez

Lensless cameras are a class of imaging devices that shrink the physical dimensions to the very close vicinity of the image sensor by replacing conventional compound lenses with integrated flat optics and computational algorithms. Here we…

Computer Vision and Pattern Recognition · Computer Science 2022-12-08 Qiang Fu , Dong-Ming Yan , Wolfgang Heidrich

The methods of determining the fractal dimension and irregularity scale in simulated galaxy catalogs and the application of these methods to the data of the 2dF and 6dF catalogs are analyzed. Correlation methods are shown to be correctly…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Nikita Yu. Lovyagin

The spatio-angular resolution of a light field (LF) display is a crucial factor for delivering adequate spatial image quality and eliciting an accommodation response. Previous studies have modelled retinal image formation with an LF display…

Image and Video Processing · Electrical Eng. & Systems 2022-10-12 Yuta Miyanishi , Erdem Sahin , Atanas Gotchev