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Image restoration is one of the most fundamental issues in imaging science. Total variation (TV) regularization is widely used in image restoration problems for its capability to preserve edges. In the literature, however, it is also well…

Computer Vision and Pattern Recognition · Computer Science 2013-10-22 Jun Liu , Ting-Zhu Huang , Ivan W. Selesnick , Xiao-Guang Lv , Po-Yu Chen

We extend a recently introduced deep unrolling framework for learning spatially varying regularisation parameters in inverse imaging problems to the case of Total Generalised Variation (TGV). The framework combines a deep convolutional…

Computer Vision and Pattern Recognition · Computer Science 2025-03-07 Thanh Trung Vu , Andreas Kofler , Kostas Papafitsoros

This paper introduces a novel variational approach for image compression motivated by recent PDE-based approaches combining edge detection and Laplacian inpainting. The essential feature is to encode the image via a sparse vector field,…

Optimization and Control · Mathematics 2015-03-09 Eva-Maria Brinkmann , Martin Burger , Joana Grah

Multispectral images (MSI) contain light information in different wavelengths of objects, which convey spectral-spatial information and help improve the performance of various image processing tasks. Numerous techniques have been created to…

Computer Vision and Pattern Recognition · Computer Science 2024-03-20 Zhantao Ma , Michael K. Ng

The use of ray projections to reconstruct images is a common technique in medical imaging. Dealing with incomplete data is particularly important when a patient is vulnerable to potentially damaging radiation or is unable to cope with the…

Neural and Evolutionary Computing · Computer Science 2024-06-04 Mohammad Majid al-Rifaie , Tim Blackwell

Total variation(TV) regularization is applied to X-Ray computed tomography(CT) in an effort to reduce metal artifacts. Tikhonov regularization with $L^2$ data fidelity term and total variation regularization is augmented in this novel model…

Numerical Analysis · Mathematics 2018-10-09 Clemens Schiffer

We propose a novel discrete concept for the total generalized variation (TGV), which has originally been derived to reduce the staircasing effect in classical total variation (TV) regularization, in image denoising problems. We describe…

Numerical Analysis · Mathematics 2022-09-27 Lukas Baumgärtner , Ronny Bergmann , Roland Herzog , Stephan Schmidt , José Vidal-Núñez

In this article, we study several reconstruction methods for the inverse source problem of photoacoustic tomography (PAT) with spatially variable sound speed and damping. The backbone of these methods is the adjoint operators, which we…

Analysis of PDEs · Mathematics 2018-08-21 Linh V. Nguyen , Markus Haltmeier

In this thesis, we offer a thorough investigation of different regularisation terms used in variational imaging problems, together with detailed optimisation processes of these problems. We begin by studying smooth problems and partially…

Computer Vision and Pattern Recognition · Computer Science 2021-10-07 Joseph Bartlett , Jinming Duan

Diffuse Optical Tomography (DOT) is an emerging technology in medical imaging which employs light in the NIR spectrum to estimate the distribution of optical coefficients in biological tissues for diagnostic and monitoring purposes. DOT…

Numerical Analysis · Mathematics 2022-05-27 Alessandro Benfenati , Giuseppe Bisazza , Paola Causin

Purpose: Iterative projection reconstruction algorithms are currently the preferred reconstruction method in proton computed tomography (pCT). However, due to inconsistencies in the measured data arising from proton energy straggling and…

Medical Physics · Physics 2015-05-20 S. N. Penfold , R. W. Schulte , Y. Censor , A. B. Rosenfeld

This work is concerned with applying iterative image reconstruction, based on constrained total-variation minimization, to low-intensity X-ray CT systems that have a high sampling rate. Such systems pose a challenge for iterative image…

Medical Physics · Physics 2016-11-17 Emil Y. Sidky , Rick Chartrand , Yuval Duchin , Christer Ullberg , Xiaochuan Pan

Previous work showed that total variation superiorization (TVS) improves reconstructed image quality in proton computed tomography (pCT). The structure of the TVS algorithm has evolved since then and this work investigated if this new…

Medical Physics · Physics 2019-01-18 Blake Schultze , Yair Censor , Paniz Karbasi , Keith E. Schubert , Reinhard W. Schulte

Positron Emission Tomography (PET) imaging is a vital tool in medical diagnostics, offering detailed insights into molecular processes within the human body. However, PET images often suffer from complicated noise, which can obscure…

Computer Vision and Pattern Recognition · Computer Science 2026-01-30 Xuehua Ye , Hongxu Yang , Adam J. Schwarz

Various problems in computer vision and medical imaging can be cast as inverse problems. A frequent method for solving inverse problems is the variational approach, which amounts to minimizing an energy composed of a data fidelity term and…

Computer Vision and Pattern Recognition · Computer Science 2020-06-17 Erich Kobler , Alexander Effland , Karl Kunisch , Thomas Pock

We propose a model-based image reconstruction method for photoacoustic tomography(PAT) involving a novel form of regularization and demonstrate its ability to recover good quality images from significantly reduced size datasets. The…

Image and Video Processing · Electrical Eng. & Systems 2020-12-29 Nadaparambil Aravindakshan Rejesh , Sandeep Kumar Kalva , Manojit Pramanik , Muthuvel Arigovindan

Small compression noises, despite being transparent to human eyes, can adversely affect the results of many image restoration processes, if left unaccounted for. Especially, compression noises are highly detrimental to inverse operators of…

Computer Vision and Pattern Recognition · Computer Science 2016-01-08 Xiao Shu , Xiaolin Wu

Spectral Computed Tomography (CT) is an emerging technology that enables to estimate the concentration of basis materials within a scanned object by exploiting different photon energy spectra. In this work, we aim at efficiently solving a…

Optimization and Control · Mathematics 2021-03-26 Alessandro Perelli , Martin S. Andersen

In image denoising problems, one widely-adopted approach is to minimize a regularized data-fit objective function, where the data-fit term is derived from a physical image acquisition model. Typically the regularizer is selected with two…

Optimization and Control · Mathematics 2015-08-13 Albert Oh , Rebecca Willett

In optoacoustic tomography, image reconstruction is often performed with incomplete or noisy data, leading to reconstruction errors. Significant improvement in reconstruction accuracy may be achieved in such cases by using nonlinear…

Image and Video Processing · Electrical Eng. & Systems 2019-08-09 Shai Biton , Nadav Arbel , Gilad Drozdov , Guy Gilboa , Amir Rosenthal