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Spectral imaging is a fundamental diagnostic technique with widespread application. Conventional spectral imaging approaches have intrinsic limitations on spatial and spectral resolutions due to the physical components they rely on. To…

Image and Video Processing · Electrical Eng. & Systems 2021-06-07 Figen S. Oktem , Oğuzhan Fatih Kar , Can Deniz Bezek , Farzad Kamalabadi

I propose a superoscillation measurement method for subdiffraction incoherent optical sources, with potential applications in astronomy, remote sensing, fluorescence microscopy, and spectroscopy. The proposal, based on coherent optical…

Quantum Physics · Physics 2022-10-10 Mankei Tsang

Spectroscopy sampling along delay time is typically performed with uniform delay spacing, which has to be low enough to satisfy the Nyquist-Shannon sampling theorem. The sampling theorem puts the lower bound for the sampling rate to ensure…

Chemical Physics · Physics 2025-03-04 Junyan Sun , Deran Zhang , Ziqian Cheng , Dazhi Xu , Hui Dong

The x-ray near-field speckle-scanning concept is an approach recently introduced to obtain absorption, phase, and dark-field images of a sample. In this paper, we present ways of recovering from a sample its ultrasmall-angle x-ray…

Optics · Physics 2015-07-24 Sebastien Berujon , Eric Ziegler

Ground-based astronomical observations will continue to produce resolution-limited images due to atmospheric seeing. Deconvolution reverses such effects and thus can benefit extracted science in multifaceted ways. We apply the Scaled…

Instrumentation and Methods for Astrophysics · Physics 2025-11-04 Yash Gondhalekar , Richard M. Feder , Matthew J. Graham , Ajit K. Kembhavi , Margarita Safonova , Snehanshu Saha , Ashish A. Mahabal

One of the main goals of modern observational cosmology is to map the large scale structure of the Universe. A potentially powerful approach for doing this would be to exploit three-dimensional spectral maps, i.e. the specific intensity of…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-18 Roland de Putter , Gilbert P. Holder , Tzu-Ching Chang , Olivier Dore

This paper presents a new method to obtain the deformation distribution on the main reflector of an antenna only by measuring the electric intensity on a spherical surface with the focal point as the center of the sphere, regardless of…

Instrumentation and Methods for Astrophysics · Physics 2021-12-08 Qian Ye , Boyang Wang , Qiang Yao , Jinqing Wang , Qinghui Liu , Zhiqiang Shen

We consider the use of digital signal processing to reconstruct continuous reflectance spectra using a small finite set of randomly illuminated light emitting diodes (LEDs). We simulate the use of LEDs having identical spectral distance and…

Optics · Physics 2025-10-29 John C. Howell , Pieter H. Neethling , Tjaart P. J. Kruger

Removing undesired reflections from images taken through the glass is of great importance in computer vision. It serves as a means to enhance the image quality for aesthetic purposes as well as to preprocess images in machine learning and…

Computer Vision and Pattern Recognition · Computer Science 2019-05-13 Yang Yang , Wenye Ma , Yin Zheng , Jian-Feng Cai , Weiyu Xu

We describe an acquisition/processing procedure for image reconstruction in dynamic Magnetic Resonance Imaging (MRI). The approach requires sliding window to record a set of trajectories in the k-space, standard regularization to…

Computational Engineering, Finance, and Science · Computer Science 2014-02-12 Cristian Toraci , Gabriele Zaccaria , Stefano Ceriani , David Wilson , Marco Fato , Michele Piana

This work is concerned with optical imaging in strongly diffusive environments. We consider a typical setting in optical coherence tomography where a sample is probed by a collection of wavefields produced by a laser and propagating through…

Optics · Physics 2024-12-10 Randy Bartels , Olivier Pinaud , Maxine Varughese

Time-resolved photoluminescence (PL) is commonly used to track dynamics in a broad range of materials. Thus, the search for simplification of the acquisition of PL kinetics attracts continuous attention. This paper presents a new robust and…

Instrumentation and Detectors · Physics 2020-04-22 Jiri Junek , Lukas Ondic , Karel Zidek

The abundant spatial and angular information from light fields has allowed the development of multiple disparity estimation approaches. However, the acquisition of light fields requires high storage and processing cost, limiting the use of…

Computer Vision and Pattern Recognition · Computer Science 2022-09-26 Emmanuel Martinez , Edwin Vargas , Henry Arguello

The segmentation of transparent objects can be very useful in computer vision applications. However, because they borrow texture from their background and have a similar appearance to their surroundings, transparent objects are not handled…

Computer Vision and Pattern Recognition · Computer Science 2015-11-24 Yichao Xu , Hajime Nagahara , Atsushi Shimada , Rin-ichiro Taniguchi

We present a structured-illumination technique for full-field super-resolution transmission X-ray microscopy, which employs Fourier spectral decomposition inspired by established methods in visible-light microscopy. A 2D grating creating…

We present a learning-based approach for removing unwanted obstructions, such as window reflections, fence occlusions, or adherent raindrops, from a short sequence of images captured by a moving camera. Our method leverages motion…

Computer Vision and Pattern Recognition · Computer Science 2021-07-27 Yu-Lun Liu , Wei-Sheng Lai , Ming-Hsuan Yang , Yung-Yu Chuang , Jia-Bin Huang

In this paper, we consider the problem of sparse signal detection based on partial support set estimation with compressive measurements in a distributed network. Multiple nodes in the network are assumed to observe sparse signals which…

Applications · Statistics 2016-08-10 Thakshila Wimalajeewa , Pramod K. Varshney

Conventional spectrometer and polarimeter systems rely on bulky optics, fundamentally limiting compact integration and hindering multi-dimensional optical sensing capabilities. Here, we propose a spectropolarimeter enabled by…

Optics · Physics 2026-04-13 Jumin Qiu , Tingting Liu , Chenxuan Xiang , Tianbao Yu , Qiegen Liu , Shuyuan Xiao

The paper introduces hidden grid background oriented schlieren for quantitative study and visualization of natural convection heat transfer. In this technique, the refractive index variation, induced by the temperature gradient, is encoded…

Signal Processing · Electrical Eng. & Systems 2022-10-04 Jagadesh Ramaiah , Tullio de Rubeis , Rajshekhar Gannavarpu , Dario Ambrosini

The spectrogram is a classical DSP tool used to view signals in both time and frequency. Unfortunately, the Heisenberg Uncertainty Principal limits our ability to use them for detecting and measuring narrowband signal modulation in wideband…

Information Theory · Computer Science 2014-01-22 Ray Maleh , Frank A. Boyle