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In cryo-electron microscopy (cryo-EM), a microscope generates a top view of a sample of randomly-oriented copies of a molecule. The problem of single particle reconstruction (SPR) from cryo-EM is to use the resulting set of noisy 2D…

Numerical Analysis · Mathematics 2014-09-16 Gene Katsevich , Alexander Katsevich , Amit Singer

Classifying structural variability in noisy projections of biological macromolecules is a central problem in Cryo-EM. In this work, we build on a previous method for estimating the covariance matrix of the three-dimensional structure…

Computer Vision and Pattern Recognition · Computer Science 2015-12-08 Joakim Andén , Eugene Katsevich , Amit Singer

Analyzing large samples of high-dimensional data under dependence is a challenging statistical problem as long time series may have change points, most importantly in the mean and the marginal covariances, for which one needs valid tests.…

Methodology · Statistics 2022-11-07 Fabian Mies , Ansgar Steland

In many astrophysical settings covariance matrices of large datasets have to be determined empirically from a finite number of mock realisations. The resulting noise degrades inference and precludes it completely if there are fewer…

Instrumentation and Methods for Astrophysics · Physics 2017-01-11 Benjamin Joachimi

Cryo-electron microscopy (cryo-EM) has emerged as a powerful technique for resolving the three-dimensional structures of macromolecules. A key challenge in cryo-EM is characterizing continuous heterogeneity, where molecules adopt a…

Machine Learning · Statistics 2026-02-20 Roey Yadgar , Roy R. Lederman , Yoel Shkolnisky

Background and Objective: The contrast of cryo-EM images varies from one to another, primarily due to the uneven thickness of the ice layer. This contrast variation can affect the quality of 2-D class averaging, 3-D ab-initio modeling, and…

Computer Vision and Pattern Recognition · Computer Science 2022-07-01 Yunpeng Shi , Amit Singer

The computational pipelines of single-particle cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET) include an early particle-picking stage, in which a micrograph or tomogram is scanned to extract candidate particles,…

Signal Processing · Electrical Eng. & Systems 2026-04-14 Amnon Balanov , Alon Zabatani , Tamir Bendory

Volumetry is one of the principal downstream applications of 3D medical image segmentation, for example, to detect abnormal tissue growth or for surgery planning. Conformal Prediction is a promising framework for uncertainty quantification,…

Computer Vision and Pattern Recognition · Computer Science 2024-07-30 Benjamin Lambert , Florence Forbes , Senan Doyle , Michel Dojat

In practice, observations are often contaminated by noise, making the resulting sample covariance matrix to be an information-plus-noise-type covariance matrix. Aiming to make inferences about the spectra of the underlying true covariance…

Statistics Theory · Mathematics 2015-08-25 Ningning Xia , Xinghua Zheng

We seek to improve estimates of the power spectrum covariance matrix from a limited number of simulations by employing a novel statistical technique known as shrinkage estimation. The shrinkage technique optimally combines an empirical…

Astrophysics · Physics 2009-11-13 Adrian C. Pope , István Szapudi

Cryo-electron microscopy (cryo-EM) has recently emerged as a powerful tool for obtaining three-dimensional (3D) structures of biological macromolecules in native states. A minimum cryo-EM image data set for deriving a meaningful…

Applications · Statistics 2014-04-28 Ting-Li Chen , Dai-Ni Hsieh , Hung Hung , I-Ping Tu , Pei-Shien Wu , Yi-Ming Wu , Wei-Hau Chang , Su-Yun Huang

In mixture models, anisotropic noise within each cluster is widely present in real-world data. This work investigates both computationally efficient procedures and fundamental statistical limits for clustering in high-dimensional…

Statistics Theory · Mathematics 2026-01-28 Chengzhu Huang , Yuqi Gu

Standard noise radars, as well as noise-type radars such as quantum two-mode squeezing radar, are characterized by a covariance matrix with a very specific structure. This matrix has four independent parameters: the amplitude of the…

Signal Processing · Electrical Eng. & Systems 2022-08-10 David Luong , Bhashyam Balaji , Sreeraman Rajan

After the recent ground-breaking advances in protein structure prediction, one of the remaining challenges in protein machine learning is to reliably predict distributions of structural states. Parametric models of fluctuations are…

Machine Learning · Computer Science 2024-01-25 Marloes Arts , Jes Frellsen , Wouter Boomsma

We develop a data-driven optimal shrinkage algorithm for matrix denoising in the presence of high-dimensional noise with a separable covariance structure; that is, the noise is colored and dependent across samples. The algorithm, coined…

Applications · Statistics 2024-05-14 Pei-Chun Su , Hau-Tieng Wu

A single-particle cryo-electron microscopy (cryo-EM) measurement, called a micrograph, consists of multiple two-dimensional tomographic projections of a three-dimensional (3-D) molecular structure at unknown locations, taken under unknown…

Image and Video Processing · Electrical Eng. & Systems 2026-03-10 Shay Kreymer , Amit Singer , Tamir Bendory

This paper tackles the problem of jointly estimating the noise covariance matrix alongside states (parameters such as poses and points) from measurements corrupted by Gaussian noise and, if available, prior information. In such settings,…

Robotics · Computer Science 2025-08-13 Kasra Khosoussi , Iman Shames

According to recent findings [1,2], empirical covariance matrices deduced from financial return series contain such a high amount of noise that, apart from a few large eigenvalues and the corresponding eigenvectors, their structure can…

Statistical Mechanics · Physics 2009-11-07 Szilard Pafka , Imre Kondor

Data re-sampling methods such as the delete-one jackknife are a common tool for estimating the covariance of large scale structure probes. In this paper we investigate the concepts of internal covariance estimation in the context of cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-10 O. Friedrich , S. Seitz , T. F. Eifler , D. Gruen

Determining the 3D structures of biological molecules is a key problem for both biology and medicine. Electron Cryomicroscopy (Cryo-EM) is a promising technique for structure estimation which relies heavily on computational methods to…

Machine Learning · Statistics 2015-01-29 Ali Punjani , Marcus A. Brubaker
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