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Total variation (TV) regularization is a popular reconstruction method for ill-posed imaging problems, and particularly useful for applications with piecewise constant targets. However, using TV for medical cone-beam computed X-ray…

医学物理 · 物理学 2024-12-11 Alexander Meaney , Mikael A. K. Brix , Miika T. Nieminen , Samuli Siltanen

Even after over two decades, the total variation (TV) remains one of the most popular regularizations for image processing problems and has sparked a tremendous amount of research, particularly to move from scalar to vector-valued…

计算机视觉与模式识别 · 计算机科学 2016-06-21 Joan Duran , Michael Moeller , Catalina Sbert , Daniel Cremers

The total variation (TV) regularization method is an effective method for image deblurring in preserving edges. However, the TV based solutions usually have some staircase effects. In this paper, in order to alleviate the staircase effect,…

数值分析 · 数学 2015-05-20 Gang Liu , Ting-Zhu Huang , Jun Liu , Xiao-Guang Lv

Recent research indicates that many convex optimization problems with random constraints exhibit a phase transition as the number of constraints increases. For example, this phenomenon emerges in the $\ell_1$ minimization method for…

信息论 · 计算机科学 2014-04-29 Dennis Amelunxen , Martin Lotz , Michael B. McCoy , Joel A. Tropp

This article studies the denoising performance of total variation (TV) image regularization. More precisely, we study geometrical properties of the solution to the so-called Rudin-Osher-Fatemi total variation denoising method. The first…

最优化与控制 · 数学 2016-12-21 Antonin Chambolle , Vincent Duval , Gabriel Peyré , Clarice Poon

High radiation dose in CT scans increases a lifetime risk of cancer and has become a major clinical concern. Recently, iterative reconstruction algorithms with Total Variation (TV) regularization have been developed to reconstruct CT images…

医学物理 · 物理学 2015-05-19 Zhen Tian , Xun Jia , Kehong Yuan , Tinsu Pan , Steve B. Jiang

Recently, we have witnessed the success of total variation (TV) for many imaging applications. However, traditional TV is defined on the original pixel domain, which limits its potential. In this work, we suggest a new TV regularization…

计算机视觉与模式识别 · 计算机科学 2025-01-03 Yisi Luo , Xile Zhao , Kai Ye , Deyu Meng

Classical optimisation theory guarantees monotonic objective decrease for gradient descent (GD) when employed in a small step size, or ``stable", regime. In contrast, gradient descent on neural networks is frequently performed in a large…

机器学习 · 计算机科学 2025-10-21 Lachlan Ewen MacDonald , Hancheng Min , Leandro Palma , Salma Tarmoun , Ziqing Xu , René Vidal

The long sampling time of diffusion models remains a significant bottleneck, which can be mitigated by reducing the number of diffusion time steps. However, the quality of samples with fewer steps is highly dependent on the noise schedule,…

Total variation (TV) is a powerful regularization method that has been widely applied in different imaging applications, but is difficult to apply to diffuse optical tomography (DOT) image reconstruction (inverse problem) due to complex and…

计算机视觉与模式识别 · 计算机科学 2019-04-08 Wenqi Lu , Jinming Duan , David Orive-Miguel , Lionel Herve , Iain B Styles

For arbitrary two probability measures on real d-space with given means and variances (covariance matrices), we provide lower bounds for their total variation distance. In the one-dimensional case, a tight bound is given.

概率论 · 数学 2022-12-27 Tomohiro Nishiyama

The total variation (TV) flow generates a scale-space representation of an image based on the TV functional. This gradient flow observes desirable features for images, such as sharp edges and enables spectral, scale, and texture analysis.…

计算机视觉与模式识别 · 计算机科学 2024-04-23 Tamara G. Grossmann , Sören Dittmer , Yury Korolev , Carola-Bibiane Schönlieb

We develop a unified mathematical framework for certified Top-$k$ attention truncation that quantifies approximation error at both the distribution and output levels. For a single attention distribution $P$ and its Top-$k$ truncation $\hat…

机器学习 · 计算机科学 2025-12-09 Georgios Tzachristas , Lei Deng , Ioannis Tzachristas , Gong Zhang , Renhai Chen

This paper considers the use of total variation regularization in the recovery of approximately gradient sparse signals from their noisy discrete Fourier samples in the context of compressed sensing. It has been observed over the last…

数值分析 · 数学 2014-07-22 Clarice Poon

The total variation (TV) penalty, as many other analysis-sparsity problems, does not lead to separable factors or a proximal operatorwith a closed-form expression, such as soft thresholding for the $\ell\_1$ penalty. As a result, in a…

神经元与认知 · 定量生物学 2015-12-23 Gaël Varoquaux , Michael Eickenberg , Elvis Dohmatob , Bertand Thirion

Compressed sensing (CS) methods in magnetic resonance imaging (MRI) offer rapid acquisition and improved image quality but require iterative reconstruction schemes with regularization to enforce sparsity. Regardless of the difficulty in…

计算机视觉与模式识别 · 计算机科学 2018-09-19 Raji Susan Mathew , Joseph Suresh Paul

Performance of optimization on quadratic problems sensitively depends on the low-lying part of the spectrum. For large (effectively infinite-dimensional) problems, this part of the spectrum can often be naturally represented or approximated…

最优化与控制 · 数学 2024-03-26 Maksim Velikanov , Dmitry Yarotsky

Analysis $\ell_1$-recovery refers to a technique of recovering a signal that is sparse in some transform domain from incomplete corrupted measurements. This includes total variation minimization as an important special case when the…

信息论 · 计算机科学 2015-10-28 Maryia Kabanava , Holger Rauhut , Hui Zhang

In this paper, a new regularization term is proposed to solve mathematical image problems. By using difference operators in the four directions; horizontal, vertical and two diagonal directions, an estimation of derivative amplitude is…

数值分析 · 数学 2022-09-14 Alireza Hosseini

Temporal video grounding (TVG) aims to retrieve the time interval of a language query from an untrimmed video. A significant challenge in TVG is the low "Semantic Noise Ratio (SNR)", which results in worse performance with lower SNR. Prior…

计算机视觉与模式识别 · 计算机科学 2023-07-21 Qi Zhang , Sipeng Zheng , Qin Jin