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Low Dose Computed Tomography suffers from a high amount of noise and/or undersampling artefacts in the reconstructed image. In the current article, a Deep Learning technique is exploited as a regularization term for the iterative…

Image and Video Processing · Electrical Eng. & Systems 2019-06-04 Shabab Bazrafkan , Vincent Van Nieuwenhove , Joris Soons , Jan De Beenhouwer , Jan Sijbers

We present a new inner-outer iterative algorithm for edge enhancement in imaging problems. At each outer iteration, we formulate a Tikhonov-regularized problem where the penalization is expressed in the 2-norm and involves a regularization…

Numerical Analysis · Mathematics 2020-12-30 Silvia Gazzola , Misha E. Kilmer , James G. Nagy , Oguz Semerici , Eric L. Miller

Photoacoustic imaging (PAI) suffers from inherent limitations that can degrade the quality of reconstructed results, such as noise, artifacts and incomplete data acquisition caused by sparse sampling or partial array detection. In this…

Optics · Physics 2025-01-07 Yu Zhang , Shuang Li , Yibing Wang , Yu Sun , Wenyi Xiang

The L1-norm of the gradient-magnitude images (GMI), which is the well-known total variation (TV) model, is widely used as regularization in the few views CT reconstruction. As the L1-norm TV regularization is tending to uniformly penalize…

Information Theory · Computer Science 2019-05-01 Yuli Sun , Jinxu Tao

This paper presents a new regularization method to train a fully convolutional network for semantic tissue segmentation in histopathological images. This method relies on the benefit of unsupervised learning, in the form of image…

Computer Vision and Pattern Recognition · Computer Science 2020-11-26 C. T. Sari , C. Sokmensuer , C. Gunduz-Demir

Crucial information barely visible to the human eye is often embedded in a series of low-resolution images taken of the same scene. Super-resolution enables the extraction of this information by reconstructing a single image, at a high…

Computer Vision and Pattern Recognition · Computer Science 2011-12-08 S. S. Panda , M. S. R. S Prasad , G. Jena

We study the problem of reconstructing a signal from its projection on a subspace. The proposed signal reconstruction algorithms utilize a guiding subspace that represents desired properties of reconstructed signals. We show that optimal…

Information Theory · Computer Science 2016-06-13 Akshay Gadde , Andrew Knyazev , Dong Tian , Hassan Mansour

Non-smooth regularization is widely used in image reconstruction to eliminate the noise while preserving subtle image structures. In this work, we investigate the use of proximal Newton (PN) method to solve an optimization problem with a…

Signal Processing · Electrical Eng. & Systems 2019-12-05 Tao Ge , Umberto Villa , Ulugbek S. Kamilov , Joseph A. O'Sullivan

Performing X-ray computed tomography (CT) examinations with less radiation has recently received increasing interest: in medical imaging this means less (potentially harmful) radiation for the patient; in non-destructive testing of…

Medical Physics · Physics 2018-09-25 Dragos Trinca , Eduard Libin

Computed Tomography (CT) imposes risk on the patients due to its inherent X-ray radiation, stimulating the development of low-dose CT (LDCT) imaging methods. Lowering the radiation dose reduces the health risks but leads to noisier…

Image and Video Processing · Electrical Eng. & Systems 2022-11-03 Elvira Zainulina , Alexey Chernyavskiy , Dmitry V. Dylov

Image denoising algorithms have been extensively investigated for medical imaging. To perform image denoising, penalized least-squares (PLS) problems can be designed and solved, in which the penalty term encodes prior knowledge of the…

Image and Video Processing · Electrical Eng. & Systems 2025-02-03 Wentao Chen , Tianming Xu , Weimin Zhou

In many applications of tomography, the acquired projections are either limited in number or contain a significant amount of noise. In these cases, standard reconstruction methods tend to produce artifacts that can make further analysis…

Numerical Analysis · Mathematics 2016-04-11 D. M. Pelt , K. J. Batenburg

In this paper, we propose an iterative algorithm to address the nonconvex multi-group multicast beamforming problem with quality-of-service constraints and per-antenna power constraints. We formulate a convex relaxation of the problem as a…

Signal Processing · Electrical Eng. & Systems 2021-11-10 Jochen Fink , Renato L. G. Cavalcante , Slawomir Stanczak

Super-resolution reconstruction techniques entail the utilization of software algorithms to transform one or more sets of low-resolution images captured from the same scene into high-resolution images. In recent years, considerable…

Computer Vision and Pattern Recognition · Computer Science 2024-08-02 Hao Yan , Zixiang Wang , Zhengjia Xu , Zhuoyue Wang , Zhizhong Wu , Ranran Lyu

Light field cameras capture the 3D information in a scene with a single exposure. This special feature makes light field cameras very appealing for a variety of applications: from post-capture refocus, to depth estimation and image-based…

Computer Vision and Pattern Recognition · Computer Science 2018-08-01 Mattia Rossi , Pascal Frossard

In the past decade, sparsity-driven regularization has led to significant improvements in image reconstruction. Traditional regularizers, such as total variation (TV), rely on analytical models of sparsity. However, increasingly the field…

Computer Vision and Pattern Recognition · Computer Science 2018-10-31 Jiaming Liu , Yu Sun , Xiaojian Xu , Ulugbek S. Kamilov

Ill-posed linear inverse problems (ILIP), such as restoration and reconstruction, are a core topic of signal/image processing. A standard approach to deal with ILIP uses a constrained optimization problem, where a regularization function is…

Optimization and Control · Mathematics 2016-11-15 Manya V. Afonso , Jose M. Bioucas-Dias , Mario A. T. Figueiredo

Deep-learning methods have shown promising performance for low-dose computed tomography (LDCT) reconstruction. However, supervised methods face the problem of lacking labeled data in clinical scenarios, and the CNN-based unsupervised…

Image and Video Processing · Electrical Eng. & Systems 2025-04-25 Ran An , Ke Chen , Hongwei Li

We propose a PDE-constrained optimization approach for the determination of noise distribution in total variation (TV) image denoising. An optimization problem for the determination of the weights correspondent to different types of noise…

Optimization and Control · Mathematics 2012-07-17 Juan-Carlos De los Reyes , Carola-Bibiane Schönlieb

Imaging is a standard example of an inverse problem, where the task of reconstructing a ground truth from a noisy measurement is ill-posed. Recent state-of-the-art approaches for imaging use deep learning, spearheaded by unrolled and…