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X-ray phase-contrast imaging offers enhanced sensitivity for weakly-attenuating materials, such as breast and brain tissue, but has yet to be widely implemented clinically due to high coherence requirements and expensive x-ray optics.…

Medical Physics · Physics 2023-05-04 Serena Qinyun Z. Shi , Nadav Shapira , Peter B. Noël , Sebastian Meyer

Quantum-optical coherence tomography (QOCT) is an optical sectioning modality based on the quantum interference of photon pairs, obtained from a spontaneous parametric downconversion (SPDC) source. The promise of QOCT derives from two…

Optical coherence tomography (OCT) is capable of non-destructively obtaining cross-sectional information of samples with micrometer spatial resolution, which plays an important role in ophthalmology and endovascular medicine. Measuring OCT…

Medical Physics · Physics 2023-11-30 Yang Jianlong , Zhang Haoran , Liu Chang , Gu Chengfu

Optical coherence tomography (OCT) is a non-invasive imaging technique with extensive clinical applications in ophthalmology. OCT enables the visualization of the retinal layers, playing a vital role in the early detection and monitoring of…

Residual speckles in adaptive optics (AO) images represent a well-known limitation on the achievement of the contrast needed for faint source detection. Speckles in AO imagery can be the result of either residual atmospheric aberrations,…

High-dynamic range imaging from space in the visible, aiming in particular at the detection of terrestrial exoplanets, necessitates not only the use of a coronagraph, but also of adaptive optics to correct optical defects in real time.…

Astrophysics · Physics 2008-11-26 Pascal J. Bordé , Wesley A. Traub

We propose an optical encryption framework that can encrypt and decrypt large-sized images beyond the size of the encrypted image using our two methods: random phase-free method and scaled diffraction. In order to record the entire image…

The scheme of optical imaging using scattering lens can provide a resolution beyond the classical optical diffraction limit with a coherent-state input. Nevertheless, due to the shot noise of the coherent state, the corresponding…

Quantum Physics · Physics 2021-04-20 Dong Li , Yao Yao

Optical coherence tomography (OCT) is a non-invasive imaging modality which is widely used in clinical ophthalmology. OCT images are capable of visualizing deep retinal layers which is crucial for early diagnosis of retinal diseases. In…

Computer Vision and Pattern Recognition · Computer Science 2019-05-28 Peyman Gholami , Priyanka Roy , Mohana Kuppuswamy Parthasarathy , Vasudevan Lakshminarayanan

We demonstrate in vivo endoscopic optical coherence tomography (OCT) imaging in the forward direction using a flexible fiber bundle. In comparison to current conventional forward looking probe schemes, our approach simplifies the endoscope…

Optical Coherence Tomography (OCT) is an imaging modality that has been widely adopted for visualizing corneal, retinal and limbal tissue structure with micron resolution. It can be used to diagnose pathological conditions of the eye, and…

Image and Video Processing · Electrical Eng. & Systems 2019-05-08 Jiahong Ouyang , Tejas Sudharshan Mathai , Kira Lathrop , John Galeotti

Optical Coherence Tomography (OCT) was originally conceived as a volumetric imaging method. Quickly, OCT images went beyond structural data and started to provide functional information about an object enabling for example visualization of…

Scatter due to interaction of photons with the imaged object is a fundamental problem in X-ray Computed Tomography (CT). It manifests as various artifacts in the reconstruction, making its abatement or correction critical for image quality.…

Medical Physics · Physics 2024-01-30 Berk Iskender , Yoram Bresler

Object-motion-based speckle correlation can recover hidden objects from any inhomogeneous medium, which takes advantage of the inherent connection that the cross-correlation between speckle patterns can reflect the autocorrelation of…

Optics · Physics 2023-12-01 Zhao Wang , Rui Ma , Mingzhu She , Anda Shi , Weili Zhang

Speckle Imaging based on triple correlation is a very efficient image reconstruction technique which is used to retrieve Fourier phase information of the object in presence of atmospheric turbulence. We have developed both Direct Bispectrum…

Instrumentation and Methods for Astrophysics · Physics 2014-09-17 Arun Surya , Swapan K. Saha

In optical coherence tomography (OCT), axial resolution and signal-to-noise ratio (SNR) are typically viewed as uncoupled parameters. We show that this is only true for mirror-like surfaces, and that in diffuse scattering samples such as…

Optics · Physics 2022-04-06 Danielle J. Harper , Benjamin J. Vakoc

SPECT (Single-photon Emission Computerized Tomography) and PET (Positron Emission Tomography) are essential medical imaging tools, for which the sampling angle number, scan time should be chosen carefully to compromise between image quality…

Medical Physics · Physics 2015-06-16 Xiaolin Zhou , Minkai Yun , Xuexiang Cao , Shuangquan Liu , Lu Wang , Xianchao Huang , Long Wei

Purpose: Spectral imaging is a method in medical x-ray imaging to extract information about the object constituents by the material-specific energy dependence of x-ray attenuation. The authors have investigated a photon-counting spectral…

Medical Physics · Physics 2021-01-21 Erik Fredenberg , Magnus Hemmendorff , Bjorn Cederstrom , Magnus Aslund , Mats Danielsson

Optical Coherence Tomography is a technique used to scan the Retina of the eye and check for tears. In this paper, we develop a Convolutional Neural Network Architecture for OCT scan classification. The model is trained to detect Retinal…

Computer Vision and Pattern Recognition · Computer Science 2022-12-01 Adit Magotra , Aagat Gedam , Tanush Savadi , Emily Li

Light passing through scattering media will be strongly scattered and diffused into complex speckle pattern, which contains almost all the spatial information and spectral information of the objects. Although various methods have been…

Optics · Physics 2019-02-04 Lei Zhu , Jietao Liu , Lei Feng , Chengfei Guo , Tengfei Wu , Xiaopeng Shao