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New techniques for imaging electromagnetic near-fields in nanostructures drive advancements in nanotechnology, optoelectronics, materials science, and biochemistry. Most existing techniques probe near-fields along surfaces, lacking the…

We develop a framework for rendering photographic images, taking into account display limitations, so as to optimize perceptual similarity between the rendered image and the original scene. We formulate this as a constrained optimization…

Computer Vision and Pattern Recognition · Computer Science 2020-07-28 Valero Laparra , Alex Berardino , Johannes Ballé , Eero P. Simoncelli

Flux reconstruction provides a framework for solving partial differential equations in which functions are discontinuously approximated within elements. Typically, this is done by using polynomials. Here, the use of radial basis functions…

Numerical Analysis · Mathematics 2022-01-06 Rob Watson , Will Trojak

With the rapid growth of neuroimaging technologies, a great effort has been dedicated recently to investigate the dynamic changes in brain activity. Examples include time course calcium imaging and dynamic brain functional connectivity. In…

Methodology · Statistics 2020-08-31 Wei Hu , Tianyu Pan , Dehan Kong , Weining Shen

Conventional LIDAR systems require hundreds or thousands of photon detections to form accurate depth and reflectivity images. Recent photon-efficient computational imaging methods are remarkably effective with only 1.0 to 3.0 detected…

Applications · Statistics 2019-11-13 Joshua Rapp , Vivek K Goyal

Radon transform is widely used in physical and life sciences and one of its major applications is the X-ray computed tomography (X-ray CT), which is significant in modern health examination. The Radon inversion or image reconstruction is…

Computer Vision and Pattern Recognition · Computer Science 2018-08-10 Ji He , Jianhua Ma

The set of diagonals of real symmetric matrices of given non negative spectrum is endowed with a measure which is obtained by the push forward of the Haar measure of the real orthogonal group.\\ We prove that the Radon Nicodym derivation of…

Representation Theory · Mathematics 2015-05-26 Avital Frumkin , Assaf Goldberger

Attenuated Radon projections with respect to the weight function $W_\mu(x,y) = (1-x^2-y^2)^{\mu-1/2}$ are shown to be closely related to the orthogonal expansion in two variables with respect to $W_\mu$. This leads to an algorithm for…

Numerical Analysis · Mathematics 2007-05-23 Yuan Xu , Oleg Tischenko , Christoph Hoeschen

We consider the problem of reconstructing an unknown function $f$ on a domain $X$ from samples of $f$ at $n$ randomly chosen points with respect to a given measure $\rho_X$. Given a sequence of linear spaces $(V_m)_{m>0}$ with ${\rm…

Numerical Analysis · Mathematics 2018-06-19 Albert Cohen , Mark A. Davenport , Dany Leviatan

High resolution images can be acquired using a non-regular sampling sensor which consists of an underlying low resolution sensor that is covered with a non-regular sampling mask. The reconstructed high resolution image is then obtained…

Image and Video Processing · Electrical Eng. & Systems 2022-04-08 Markus Jonscher , Karina Jaskolka , Jürgen Seiler , André Kaup

Compact gamma cameras with a square-shaped monolithic scintillator crystal and an array of silicon photomultipliers (SiPMs) are actively being developed for applications in areas such as small animal imaging, cancer diagnostics and…

Medical Physics · Physics 2017-04-26 A. Morozov , F. Alves , J. Marcos , R. Martins , L. Pereira , V. Solovov , V. Chepel

Image resampling is a necessary component of any operation that changes the size of an image or its geometry. Methods tuned for natural image upsampling (roughly speaking, image enlargement) are analyzed and developed with a focus on their…

Graphics · Computer Science 2015-03-20 Chantal Racette

Let $f\in L^1(\R^d)$ be real. The Rudin-Osher-Fatemi model is to minimize $\|u\|_{\dot{BV}}+\lambda\|f-u\|_{L^2}^2$, in which one thinks of $f$ as a given image, $\lambda > 0$ as a "tuning parameter", $u$ as an optimal "cartoon"…

Analysis of PDEs · Mathematics 2012-04-06 John B. Garnett , Triet M. Le , Luminita A. Vese

The ill-posed problem of phase retrieval in optics, using one or more intensity measurements, has a multitude of applications using electromagnetic or matter waves. Many phase retrieval algorithms are computed on pixel arrays using discrete…

Image and Video Processing · Electrical Eng. & Systems 2022-09-21 J. A. Pollock , K. S. Morgan , L. C. P. Croton , M. K. Croughan , G. Ruben , N. Yagi , H. Sekiguchi , M. J. Kitchen

Image super-resolution using self-optimizing mask via fractional-order gradient interpolation and reconstruction aims to recover detailed information from low-resolution images and reconstruct them into high-resolution images. Due to the…

Computer Vision and Pattern Recognition · Computer Science 2017-03-21 Qi Yang , Yanzhu Zhang , Tiebiao Zhao , YangQuan Chen

Purpose: To reconstruct artifact-free images from measured k-space data, when the actual k-space trajectory deviates from the nominal trajectory due to gradient imperfections. Methods: Trajectory errors arising from eddy currents and…

Medical Physics · Physics 2018-02-13 Merry Mani , Vincent Magnotta , Mathews Jacob

Following the recent developement of Fourier ptychographic microscopy (FPM) in the visible range by Zheng et al. (2013), we propose an adaptation for hard x-rays. FPM employs ptychographic reconstruction to merge a series of low-resolution,…

Instrumentation and Detectors · Physics 2016-09-27 H. Simons , H. F. Poulsen , J. P. Guigay , C. Detlefs

In this work we describe a fast and stable algorithm for the computation of the orthogonal moments of an image. Indeed, orthogonal moments are characterized by a high discriminative power, but some of their possible formulations are…

Numerical Analysis · Mathematics 2021-09-21 C. Di Ruberto , L. Putzu , G. Rodriguez

Data processing has to deal with many practical difficulties. Data is often corrupted by artifacts or noise and acquiring data can be expensive and difficult. Thus, the given data is often incomplete and inaccurate. To overcome these…

Numerical Analysis · Mathematics 2022-11-18 Florian Bossmann , Jianwei Ma

A long-standing topic in artificial intelligence is the effective recognition of patterns from noisy images. In this regard, the recent data-driven paradigm considers 1) improving the representation robustness by adding noisy samples in…

Computer Vision and Pattern Recognition · Computer Science 2024-06-21 Shuren Qi , Yushu Zhang , Chao Wang , Tao Xiang , Xiaochun Cao , Yong Xiang