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Many man-made objects are characterised by a shape that is symmetric along one or more planar directions. Estimating the location and orientation of such symmetry planes can aid many tasks such as estimating the overall orientation of an…

Computer Vision and Pattern Recognition · Computer Science 2021-07-01 Mihaela Cătălina Stoian , Tommaso Cavallari

In this work we: (1) review likelihood-based inference for parameter estimation and the construction of confidence regions; and, (2) explore the use of techniques from information geometry, including geodesic curves and Riemann scalar…

Methodology · Statistics 2022-04-01 Jesse A Sharp , Alexander P Browning , Kevin Burrage , Matthew J Simpson

The application of wide field-of-view detection systems to atom probe experiments emphasizes the importance of careful parameter selection in the tomographic reconstruction of the analysed volume, as the sensitivity to errors rises steeply…

Instrumentation and Detectors · Physics 2015-10-13 Baptiste Gault , Frederic De Geuser , Leigh T. Stephenson , Michael P. Moody , Barry C. Muddle , Simon P. Ringer

X-ray tomography has applications in various industrial fields such as sawmill industry, oil and gas industry, chemical engineering, and geotechnical engineering. In this article, we study Bayesian methods for the X-ray tomography…

Computational Engineering, Finance, and Science · Computer Science 2020-03-26 Jarkko Suuronen , Muhammad Emzir , Sari Lasanen , Simo Särkkä , Lassi Roininen

The X-ray diffractometer in the laboratory is a crucial instrument for analyzing materials in science. It can be used on almost any crystal material, and if the machine parameters are appropriately controlled, it can offer a lot of…

Applied Physics · Physics 2024-08-23 Hamidreza Moradi , Fatemeh Mehradnia

We transpose an optimal control technique to the image segmentation problem. The idea is to consider image segmentation as a parameter estimation problem. The parameter to estimate is the color of the pixels of the image. We use the…

Numerical Analysis · Mathematics 2011-05-24 Hend Ben Ameur , Guy Chavent , Francois Clément , Pierre Weis

The MARS scanner is designed for the x-ray spectroscopic study of samples with the aid of computer tomography methods. Computer tomography allows the reconstruction of slices of an investigated sample using a set of shadow projections…

We describe regularized methods for image reconstruction and focus on the question of hyperparameter and instrument parameter estimation, i.e. unsupervised and myopic problems. We developed a Bayesian framework that is based on the \post…

Instrumentation and Methods for Astrophysics · Physics 2012-11-16 F. Orieux , J. -F. Giovannelli , T. Rodet , A. Abergel

Recently, sparsity-based algorithms are proposed for super-resolution spectrum estimation. However, to achieve adequately high resolution in real-world signal analysis, the dictionary atoms have to be close to each other in frequency,…

Machine Learning · Statistics 2015-06-05 Yiyuan She , Huanghuang Li , Jiangping Wang , Dapeng Wu

In tomographic reconstruction, the goal is to reconstruct an unknown object from a collection of line integrals. Given a complete sampling of such line integrals for various angles and directions, explicit inverse formulas exist to…

Numerical Analysis · Mathematics 2018-01-18 Tristan van Leeuwen , Simon Maretzke , K. Joost Batenburg

We present the framework of slowly varying regression under sparsity, allowing sparse regression models to exhibit slow and sparse variations. The problem of parameter estimation is formulated as a mixed-integer optimization problem. We…

Machine Learning · Computer Science 2023-11-14 Dimitris Bertsimas , Vassilis Digalakis , Michael Linghzi Li , Omar Skali Lami

We compute approximate solutions to inverse problems for determining parameters in differential equation models with stochastic data on output quantities. The formulation of the problem and modeling framework define a solution as a…

Numerical Analysis · Mathematics 2014-07-16 Troy Butler , Don Estep , Simon Tavener , Timothy Wildey , Clint Dawson , Lindley Graham

We present a procedure to reconstruct objects from holograms recorded in in-line holography settings. Working with one beam of polarized light, the topological derivatives and energies of functionals quantifying hologram deviations yield…

Optics · Physics 2018-04-09 A. Carpio , T. G. Dimiduk , V. Selgas , P. Vidal

We propose a new algorithm to compute the X-ray transform of an image represented by unit (pixel/voxel) basis functions. The fundamental issue is equivalently calculating the intersection lengths of the ray with associated units. For any…

Numerical Analysis · Mathematics 2024-08-28 Chong Chen , Runqian Wang , Chandrajit Bajaj , Ozan Öktem

Many problems of low-level computer vision and image processing, such as denoising, deconvolution, tomographic reconstruction or super-resolution, can be addressed by maximizing the posterior distribution of a sparse linear model (SLM). We…

Machine Learning · Statistics 2010-08-16 Matthias W. Seeger , Hannes Nickisch

Most datasets encountered in computer vision and medical applications present symmetries that should be taken into account in classification tasks. A typical example is the symmetry by rotation and/or scaling in object detection. A common…

Computer Vision and Pattern Recognition · Computer Science 2025-12-23 Ioana Ciuclea , Giorgio Longari , Alice Barbara Tumpach

The theory of semiparametric estimation offers an elegant way of computing the Cram\'er-Rao bound for a parameter of interest in the midst of infinitely many nuisance parameters. Here I apply the theory to the problem of moment estimation…

Image and Video Processing · Electrical Eng. & Systems 2019-10-09 Mankei Tsang

Feature matching is a challenging computer vision task that involves finding correspondences between two images of a 3D scene. In this paper we consider the dense approach instead of the more common sparse paradigm, thus striving to find…

Computer Vision and Pattern Recognition · Computer Science 2022-11-28 Johan Edstedt , Ioannis Athanasiadis , Mårten Wadenbäck , Michael Felsberg

We consider estimation of a sparse parameter vector that determines the covariance matrix of a Gaussian random vector via a sparse expansion into known "basis matrices". Using the theory of reproducing kernel Hilbert spaces, we derive lower…

Information Theory · Computer Science 2011-01-21 Alexander Jung , Sebastian Schmutzhard , Franz Hlawatsch , Alfred O. Hero

Minimizing a convex function of a measure with a sparsity-inducing penalty is a typical problem arising, e.g., in sparse spikes deconvolution or two-layer neural networks training. We show that this problem can be solved by discretizing the…

Optimization and Control · Mathematics 2020-11-04 Lenaic Chizat