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Inverse problems arise in a wide spectrum of applications in fields ranging from engineering to scientific computation. Connected with the rise of interest in inverse problems is the development and analysis of regularization methods, such…

Numerical Analysis · Mathematics 2025-05-12 Abinash Nayak

In observational astronomy, noise obscures signals of interest. Large-scale astronomical surveys are growing in size and complexity, which will produce more data and increase the workload of data processing. Developing automated tools, such…

Instrumentation and Methods for Astrophysics · Physics 2022-09-16 Yunchong Zhang , Brian Nord , Amanda Pagul , Michael Lepori

Image subtraction in astronomy is a tool for transient object discovery and characterization, particularly useful in wide fields, and is well suited for moving or photometrically varying objects such as asteroids, extra-solar planets and…

Instrumentation and Methods for Astrophysics · Physics 2013-01-09 Steven Hartung

Applying a transformation to a non-Gaussian field can enhance the information content of the resulting power spectrum, by reducing the correlations between Fourier modes. In the context of weak gravitational lensing, it has been shown that…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-16 Fergus Simpson , Joachim Harnois-Déraps , Catherine Heymans , Raul Jimenez , Benjamin Joachimi , Licia Verde

In this paper, we propose a new method for Salt-and-Pepper noise removal from images. Whereas most of the existing methods are based on Ordered Statistics filters, our method is based on the growing theory of Sparse Signal Processing. In…

Information Theory · Computer Science 2011-11-15 Abbas Kazerooni , Azarang Golmohammadi , Farokh Marvasti

In this paper, we propose a novel sparse recovery method based on the generalized error function. The penalty function introduced involves both the shape and the scale parameters, making it very flexible. The theoretical analysis results in…

Numerical Analysis · Mathematics 2021-06-04 Zhiyong Zhou

We investigate the problem of estimating the 3D shape of an object defined by a set of 3D landmarks, given their 2D correspondences in a single image. A successful approach to alleviating the reconstruction ambiguity is the 3D deformable…

Computer Vision and Pattern Recognition · Computer Science 2017-01-12 Xiaowei Zhou , Menglong Zhu , Spyridon Leonardos , Kostas Daniilidis

The statistics of peak counts in reconstructed shear maps contain information beyond the power spectrum, and can improve cosmological constraints from measurements of the power spectrum alone if systematic errors can be controlled. We study…

Weak gravitational lensing is becoming a mature technique for constraining cosmological parameters, and future surveys will be able to constrain the dark energy equation of state $w$. When analyzing galaxy surveys, redshift information has…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-07 Andrea Petri , Morgan May , Zoltán Haiman

Continuous-domain visual signals are usually captured as discrete (digital) images. This operation is not invertible in general, in the sense that the continuous-domain signal cannot be exactly reconstructed based on the discrete image,…

Information Theory · Computer Science 2016-01-20 Mitra Fatemi , Arash Amini , Loic Baboulaz , Martin Vetterli

Dedicated 'Stage IV' observatories will soon observe the entire extragalactic sky, to measure the 'cosmic shear' distortion of galaxy shapes by weak gravitational lensing. To measure the apparent shapes of those galaxies, we present an…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-08 Xiangchong Li , Yin Li , Richard Massey

Since time immemorial, noise has been a constant source of disturbance to the various entities known to mankind. Noise models of different kinds have been developed to study noise in more detailed fashion over the years. Image processing,…

Computer Vision and Pattern Recognition · Computer Science 2016-11-01 Arjun Chaudhuri

In this paper we propose a blind deconvolution method which applies to data perturbed by Poisson noise. The objective function is a generalized Kullback-Leibler divergence, depending on both the unknown object and unknown point spread…

Instrumentation and Methods for Astrophysics · Physics 2013-11-25 M. Prato , A. La Camera , S. Bonettini , M. Bertero

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

In this paper, we study the problem of recovering a sharp version of a given blurry image when the blur kernel is unknown. Previous methods often introduce an image-independent regularizer (such as Gaussian or sparse priors) on the desired…

Computer Vision and Pattern Recognition · Computer Science 2014-04-23 Guangcan Liu , Shiyu Chang , Yi Ma

The Bayesian gravitational shear estimation algorithm developed by Bernstein and Armstrong (2014) can potentially be used to overcome multiplicative noise bias and recover shear using very low signal-to-noise ratio (S/N) galaxy images. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Erin S. Sheldon

Traditional dictionary learning based CT reconstruction methods are patch-based and the features learned with these methods often contain shifted versions of the same features. To deal with these problems, the convolutional sparse coding…

Medical Physics · Physics 2018-10-16 Peng Bao , Wenjun Xia , Kang Yang , Jiliu Zhou , Yi Zhang

The stochastic order redshift technique (SORT) is a simple, efficient, and robust method to improve cosmological redshift measurements. The method relies upon having a small ($\sim$10 per cent) reference sample of high-quality redshifts.…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-25 James Kakos , Joel R. Primack , Aldo Rodriguez-Puebla , Nicolas Tejos , L. Y. Aaron Yung , Rachel S. Somerville

Strong gravitational lensing offers a wealth of astrophysical information on the background source it affects, provided the lensed source can be reconstructed as if it was seen in the absence of lensing. In the present work, we illustrate…

Instrumentation and Methods for Astrophysics · Physics 2019-02-27 R. Joseph , F. Courbin , J. -L. Starck , S. Birrer

Weak gravitational lensing has the potential to place tight constraints on the equation of the state of dark energy. However, this will only be possible if shear measurement methods can reach the required level of accuracy. We present a new…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 Guldariya Nurbaeva , Malte Tewes , Frederic Courbin , Georges Meylan