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Recently, rectified flow (RF)-based models have achieved state-of-the-art performance in many areas for both the multi-step and one-step generation. However, only a few theoretical works analyze the discretization complexity of RF-based…

Machine Learning · Computer Science 2025-08-13 Ruofeng Yang , Zhaoyu Zhu , Bo Jiang , Cheng Chen , Shuai Li

We discuss the problem of estimating Radon-Nikodym derivatives. This problem appears in various applications, such as covariate shift adaptation, likelihood-ratio testing, mutual information estimation, and conditional probability…

Statistics Theory · Mathematics 2023-08-16 Duc Hoan Nguyen , Werner Zellinger , Sergei V. Pereverzyev

Reconstructing an image from its Radon transform is a fundamental computed tomography (CT) task arising in applications such as X-ray scans. In many practical scenarios, a full 180-degree scan is not feasible, or there is a desire to reduce…

Computer Vision and Pattern Recognition · Computer Science 2025-02-20 Ilmari Vahteristo , Zhi-Song Liu , Andreas Rupp

Recovering a function from integrals over conical surfaces recently got significant interest. It is relevant for emission tomography with Compton cameras and other imaging applications. In this paper, we consider the weighted conical Radon…

Numerical Analysis · Mathematics 2018-12-05 Markus Haltmeier , Daniela Schiefeneder

In this paper, we investigate the relations between the Radon and weighted divergent beam and cone transforms. Novel inversion formulas are derived for the latter two. The weighted cone transform arises, for instance, in image…

Numerical Analysis · Mathematics 2016-12-23 Peter Kuchment , Fatma Terzioglu

We consider discrete analogues of fractional Radon transforms involving integration over paraboloids defined by positive definite quadratic forms. We prove that such discrete operators extend to bounded operators from $\ell^p$ to $\ell^q$…

Classical Analysis and ODEs · Mathematics 2019-12-19 Lillian B. Pierce

The advantages of convergent beam electron diffraction for symmetry determination at the scale of a few nm are well known. In practice, the approach is often limited due to the restriction on the angular range of the electron beam imposed…

Materials Science · Physics 2013-07-09 Richard Beanland , Paul J. Thomas , David I. Woodward , Pamela A. Thomas , Rudolf A. Roemer

Pixel detectors typically display pixel-to-pixel gain variation of a few percent which result in reduced spectroscopic performance. We have developed a calibration method which relies on cross-correlating histograms of many pixel pairs and…

Instrumentation and Detectors · Physics 2019-07-17 G. Blaj , G. Haller , C. J. Kenney

Gas transport and other complex real-world challenges often require solving and controlling partial differential equations (PDEs) defined on graph structures, which typically demand substantial memory and computational resources. The Random…

Numerical Analysis · Mathematics 2025-06-16 Martín Hernández , Enrique Zuazua

Higher-order regularization problem formulations are popular frameworks used in machine learning, inverse problems and image/signal processing. In this paper, we consider the computational problem of finding the minimizer of the Sobolev…

Numerical Analysis · Mathematics 2023-10-20 Adrien Weihs , Jalal Fadili , Matthew Thorpe

We study the convergence of the new family of mimetic finite difference schemes for linear diffusion problems recently proposed in [38]. In contrast to the conventional approach, the diffusion coefficient enters both the primary mimetic…

Numerical Analysis · Mathematics 2016-12-07 G. Manzini , K. Lipnikov , J. D. Moulton , M. Shashkov

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

Promoted by the advent of coherent synchrotron light sources, phase contrast tomography allows to resolve three-dimensional variations of an unknown sample's complex refractive index from scattering intensities recorded at different…

Numerical Analysis · Mathematics 2015-02-19 Simon Maretzke

Boundary detection of irregular and translucent objects is an important problem with applications in medical imaging, environmental monitoring and manufacturing, where many of these applications are plagued with scarce labeled data and low…

Computer Vision and Pattern Recognition · Computer Science 2026-04-14 Fei Yu Guan , Ian Keefe , Sophie Wilkinson , Daniel D. B. Perrakis , Steven Waslander

Understanding visual scenes relies more and more on dense pixel-wise classification obtained via deep fully convolutional neural networks. However, due to the nature of the networks, predictions often suffer from blurry boundaries and…

Neural and Evolutionary Computing · Computer Science 2019-09-05 Nicolas Audebert , Alexandre Boulch , Bertrand Le Saux , Sébastien Lefèvre

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

We consider stochastic gradient methods under the interpolation regime where a perfect fit can be obtained (minimum loss at each observation). While previous work highlighted the implicit regularization of such algorithms, we consider an…

Optimization and Control · Mathematics 2020-04-01 Anant Raj , Francis Bach

Novel analysis of finite dimensional Hilbert space is outlined. The approach bypasses general, inherent, difficulties present in handling angular variables in finite dimensional problems: The finite dimensional, d, Hilbert space operators…

Quantum Physics · Physics 2016-11-26 M. Revzen

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

Deformable image registration is a standard engineering problem used to determine the distortion experienced by a body by comparing two images of it in different states. This study introduces two new DIR methods designed to capture…

Computer Vision and Pattern Recognition · Computer Science 2024-09-04 Daniel E. Hurtado , Axel Osses , Rodrigo Quezada