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This paper continues our earlier investigations into the inversion of random functions in a general (abstract) setting. In Section 2 we investigate a concept of invertibility and the invertibility of the composition of random functions. In…

Probability · Mathematics 2007-05-23 Mike A. Steel , Laszlo A. Szekely

Matrix inversion problems are often encountered in experimental physics, and in particular in high-energy particle physics, under the name of unfolding. The true spectrum of a physical quantity is deformed by the presence of a detector,…

Machine Learning · Statistics 2020-09-08 Pietro Vischia

We derive an efficient stochastic algorithm for inverse problems that present an unknown linear forcing term and a set of nonlinear parameters to be recovered. It is assumed that the data is noisy and that the linear part of the problem is…

Numerical Analysis · Mathematics 2019-09-17 Darko Volkov

Inverse imaging problems that are ill-posed can be encountered across multiple domains of science and technology, ranging from medical diagnosis to astronomical studies. To reconstruct images from incomplete and distorted data, it is…

Image and Video Processing · Electrical Eng. & Systems 2023-11-30 Cesar F. Caiafa , Ramiro M. Irastorza

We model the shape and spin characteristics of an object population when there are not enough data to model its single members. The data are random projection areas of the members. We construct a mapping $f(x)\rightarrow C(y)$,…

Data Analysis, Statistics and Probability · Physics 2016-06-03 Hari Nortunen , Mikko Kaasalainen

Probability density estimation is a classical and well studied problem, but standard density estimation methods have historically lacked the power to model complex and high-dimensional image distributions. More recent generative models…

Machine Learning · Computer Science 2019-02-27 Ryen Krusinga , Sohil Shah , Matthias Zwicker , Tom Goldstein , David Jacobs

Refractive Index Tomography is the inverse problem of reconstructing the continuously-varying 3D refractive index in a scene using 2D projected image measurements. Although a purely refractive field is not directly visible, it bends light…

Computer Vision and Pattern Recognition · Computer Science 2023-12-06 Brandon Zhao , Aviad Levis , Liam Connor , Pratul P. Srinivasan , Katherine L. Bouman

Methods for anomaly detection of new physics processes are often limited to low-dimensional spaces due to the difficulty of learning high-dimensional probability densities. Particularly at the constituent level, incorporating desirable…

High Energy Physics - Phenomenology · Physics 2024-03-06 Vinicius Mikuni , Benjamin Nachman

We consider the problem of finding the probability that a random triangle is obtuse, which was first raised by Lewis Caroll. Our investigation leads us to a natural correspondence between plane polygons and the Grassmann manifold of…

Metric Geometry · Mathematics 2019-10-23 Jason Cantarella , Tom Needham , Clayton Shonkwiler , Gavin Stewart

In this work, we study the problem of reconstructing shapes from simple nonasymptotic densities measured only along shape boundaries. The particular density we study is also known as the integral area invariant and corresponds to the area…

Classical Analysis and ODEs · Mathematics 2014-08-28 Sharif Ibrahim , Kevin Sonnanburg , Thomas J. Asaki , Kevin R. Vixie

Ptychography is a scanning coherent diffractive imaging technique that enables imaging nanometer-scale features in extended samples. One main challenge is that widely used iterative image reconstruction methods often require significant…

Image and Video Processing · Electrical Eng. & Systems 2024-12-17 Canberk Ekmekci , Tekin Bicer , Zichao Wendy Di , Junjing Deng , Mujdat Cetin

Small-angle scattering tensor tomography is a technique for studying anisotropic nanostructures of millimeter-sized samples in a volume-resolved manner. It requires the acquisition of data through repeated tomographic rotations about an…

New type of tomographic probability distribution, which contains complete information on the density matrix (wave function) related to the Fresnel transform of the complex wave function, is introduced. Relation to symplectic tomographic…

Quantum Physics · Physics 2007-05-23 S. De Nicola , R. Fedele , M. A. Man'ko , V. I. Man'ko

We lay the foundations for a new fast method to reconstruct the electron density in x-ray scanning applications using measurements in the dark field. This approach is applied to a type of machine configuration with fixed energy sensitive…

Numerical Analysis · Mathematics 2015-05-08 James Webber

In 3-D reconstruction problems, the image data obtained from cryo electron microscopy is the projection of many heterogeneous instances of the object under study (e.g., a virus). When the object is heterogeneous but has an overall symmetry,…

Quantitative Methods · Quantitative Biology 2016-11-22 Nan Xu , Peter C. Doershuck

We consider the problem of estimating rare event probabilities, focusing on systems whose evolution is governed by differential equations with uncertain input parameters. If the system dynamics is expensive to compute, standard sampling…

Computation · Statistics 2019-11-05 Siddhant Wahal , George Biros

One of the fundamental problems in machine learning is the estimation of a probability distribution from data. Many techniques have been proposed to study the structure of data, most often building around the assumption that observations…

Machine Learning · Statistics 2013-02-22 Oren Rippel , Ryan Prescott Adams

We consider a random diffusion dynamics for an infinite system of hard spheres of two different sizes evolving in $\mathbb{R}^d$, its reversible probability measure, and its projection on the subset of the large spheres. The main feature is…

Probability · Mathematics 2024-03-05 Myriam Fradon , Julian Kern , Sylvie Roelly , Alexander Zass

Reconstructing 3D distributions from their 2D projections is a ubiquitous problem in various scientific fields, particularly so in observational astronomy. In this work, we present a new approach to solving this problem: a Vienna…

Instrumentation and Methods for Astrophysics · Physics 2020-01-22 B. Hasenberger , J. Alves

Inverse scattering problems without the phase information arise in imaging of nanostructures whose sizes are hundreds of nanometers as well as in imaging of biological cells. The governing equation is the 3-d generalized Helmholtz equation…

Analysis of PDEs · Mathematics 2015-10-05 Michael V. Klibanov , Loc H. Nguyen , Kejia Pan
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