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Multi-view image acquisition systems with two or more cameras can be rather costly due to the number of high resolution image sensors that are required. Recently, it has been shown that by covering a low resolution sensor with a non-regular…

Image and Video Processing · Electrical Eng. & Systems 2022-04-11 Markus Jonscher , Jürgen Seiler , Thomas Richter , Michel Bätz , André Kaup

High resolution images can be acquired using a non-regular sampling sensor which consists of an underlying low resolution sensor that is covered with a non-regular sampling mask. The reconstructed high resolution image is then obtained…

Image and Video Processing · Electrical Eng. & Systems 2022-04-08 Markus Jonscher , Karina Jaskolka , Jürgen Seiler , André Kaup

Lossy image compression networks aim to minimize the latent entropy of images while adhering to specific distortion constraints. However, optimizing the neural network can be challenging due to its nature of learning quantized latent…

Computer Vision and Pattern Recognition · Computer Science 2025-03-14 Yingwen Zhang , Meng Wang , Xihua Sheng , Peilin Chen , Junru Li , Li Zhang , Shiqi Wang

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

Total Variation (TV) and related extensions have been popular in image restoration due to their robust performance and wide applicability. While the original formulation is still relevant after two decades of extensive research, its…

Image and Video Processing · Electrical Eng. & Systems 2021-06-02 Sanjay Viswanath , Simon de Beco , Maxime Dahan , Muthuvel Arigovindan

We propose a set of iterative regularization algorithms for the TV-Stokes model to restore images from noisy images with Gaussian noise. These are some extensions of the iterative regularization algorithm proposed for the classical…

Numerical Analysis · Mathematics 2020-09-28 Bin Wu , Leszek Marcinkowski , Xue-Cheng Tai , Talal Rahman

Variational methods in imaging are nowadays developing towards a quite universal and flexible tool, allowing for highly successful approaches on tasks like denoising, deblurring, inpainting, segmentation, super-resolution, disparity, and…

Optimization and Control · Mathematics 2014-12-16 Martin Burger , Alex Sawatzky , Gabriele Steidl

Dynamic inverse problems are challenging to solve due to the need to identify and incorporate appropriate regularization in both space and time. Moreover, the very large scale nature of such problems in practice presents an enormous…

Numerical Analysis · Mathematics 2025-01-23 Toluwani Okunola , Mirjeta Pasha , Misha Kilmer , Melina Freitag

This paper focuses on the development of a space-variant regularization model for solving an under-determined linear inverse problem. The case study is a medical image reconstruction from few-view tomographic noisy data. The primary…

Image and Video Processing · Electrical Eng. & Systems 2024-04-29 Elena Morotti , Davide Evangelista , Andrea Sebastiani , Elena Loli Piccolomini

X-ray ptychography is one of the versatile techniques for nanometer resolution imaging. The magnitude of the diffraction patterns is recorded on a detector and the phase of the diffraction patterns is estimated using phase retrieval…

Image and Video Processing · Electrical Eng. & Systems 2021-05-21 Prasan Shedligeri , Florian Schiffers , Semih Barutcu , Pablo Ruiz , Aggelos K Katsaggelos , Oliver Cossairt

Image harmonization is an important step in photo editing to achieve visual consistency in composite images by adjusting the appearances of foreground to make it compatible with background. Previous approaches to harmonize composites are…

Computer Vision and Pattern Recognition · Computer Science 2020-06-02 Konstantin Sofiiuk , Polina Popenova , Anton Konushin

Most existing super-resolution methods do not perform well in real scenarios due to lack of realistic training data and information loss of the model input. To solve the first problem, we propose a new pipeline to generate realistic…

Image and Video Processing · Electrical Eng. & Systems 2019-05-30 Xiangyu Xu , Yongrui Ma , Wenxiu Sun

Image inverse halftoning is a classic image restoration task, aiming to recover continuous-tone images from halftone images with only bilevel pixels. Because the halftone images lose much of the original image content, inverse halftoning is…

Computer Vision and Pattern Recognition · Computer Science 2023-05-30 Feiyu Li , Jun Yang

This paper proposes a precise signal recovery method with multilayered non-convex regularization, enhancing sparsity/low-rankness for high-dimensional signals including images and videos. In optimization-based signal recovery, multilayered…

Signal Processing · Electrical Eng. & Systems 2024-09-24 Akari Katsuma , Seisuke Kyochi , Shunsuke Ono , Ivan Selesnick

Image restoration is a long-standing problem in low-level computer vision with many interesting applications. We describe a flexible learning framework based on the concept of nonlinear reaction diffusion models for various image…

Computer Vision and Pattern Recognition · Computer Science 2016-08-23 Yunjin Chen , Thomas Pock

This paper presents a multilevel framework for inertial and inexact proximal algorithms, that encompasses multilevel versions of classical algorithms such as forward-backward and FISTA. The methods are supported by strong theoretical…

Optimization and Control · Mathematics 2024-04-03 Guillaume Lauga , Elisa Riccietti , Nelly Pustelnik , Paulo Gonçalves

In the past decade, sparsity-driven regularization has led to advancement of image reconstruction algorithms. Traditionally, such regularizers rely on analytical models of sparsity (e.g. total variation (TV)). However, more recent methods…

Computer Vision and Pattern Recognition · Computer Science 2018-07-04 Emrah Bostan , Ulugbek S. Kamilov , Laura Waller

The unrolling method has been investigated for learning variational models in X-ray computed tomography. However, it has been observed that directly unrolling the regularization model through gradient descent does not produce satisfactory…

Image and Video Processing · Electrical Eng. & Systems 2024-04-19 Yijie Yang , Qifeng Gao , Yuping Duan

We consider a bilevel optimisation approach for parameter learning in higher-order total variation image reconstruction models. Apart from the least squares cost functional, naturally used in bilevel learning, we propose and analyse an…

Optimization and Control · Mathematics 2020-02-13 J. C. De los Reyes , C. -B. Schönlieb , T. Valkonen

The aim of image restoration is to recover high-quality images from distorted ones. However, current methods usually focus on a single task (\emph{e.g.}, denoising, deblurring or super-resolution) which cannot address the needs of…

Computer Vision and Pattern Recognition · Computer Science 2023-08-08 Cheng Zhang , Yu Zhu , Qingsen Yan , Jinqiu Sun , Yanning Zhang