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We propose a novel method to accurately reconstruct a set of images representing a single scene from few linear multi-view measurements. Each observed image is modeled as the sum of a background image and a foreground one. The background…

Computer Vision and Pattern Recognition · Computer Science 2013-09-19 Gilles Puy , Pierre Vandergheynst

Bilevel learning is a powerful optimization technique that has extensively been employed in recent years to bridge the world of model-driven variational approaches with data-driven methods. Upon suitable parametrization of the desired…

For many applications, we need to use techniques to represent convex shapes and objects. In this work, we use level set method to represent shapes and find a necessary and sufficient condition on the level set function to guarantee the…

Numerical Analysis · Mathematics 2018-11-13 Shousheng Luo , Xue-cheng Tai

Level set methods are widely used for image segmentation because of their capability to handle topological changes. In this paper, we propose a novel parametric level set method called Disjunctive Normal Level Set (DNLS), and apply it to…

Computer Vision and Pattern Recognition · Computer Science 2016-06-27 Fitsum Mesadi , Mujdat Cetin , Tolga Tasdizen

In this paper we present a bilevel optimization scheme for the solution of a general image deblurring problem, in which a parametric variational-like approach is encapsulated within a machine learning scheme to provide a high quality…

Image and Video Processing · Electrical Eng. & Systems 2022-10-20 Silvia Bonettini , Giorgia Franchini , Danilo Pezzi , Marco Prato

Creating geometric abstracted models from image-based scene reconstructions is difficult due to noise and irregularities in the reconstructed model. In this paper, we present a geometric modeling method for noisy reconstructions dominated…

Computer Vision and Pattern Recognition · Computer Science 2014-04-22 Thomas Holzmann , Christof Hoppe , Stefan Kluckner , Horst Bischof

We focus on a geometrical inverse problem that involves recovering discontinuities in electrical conductivity based on boundary measurements. This problem serves as a model to introduce a shape recovery technique that merges the…

Numerical Analysis · Mathematics 2025-01-28 Bastian Harrach , Houcine Meftahi

We consider regularization methods based on the coupling of Tikhonov regularization and projection strategies. From the resulting constraint regularization method we obtain level set methods in a straight forward way. Moreover, we show that…

Optimization and Control · Mathematics 2020-11-17 A. Leitao , O. Scherzer

Topology optimization is a valuable tool in engineering, facilitating the design of optimized structures. However, topological changes often require a remeshing step, which can become challenging. In this work, we propose an isogeometric…

Numerical Analysis · Mathematics 2026-05-01 Guilherme Henrique Teixeira , Nepomuk Krenn , Peter Gangl , Benjamin Marussig

Image segmentation is to extract meaningful objects from a given image. For degraded images due to occlusions, obscurities or noises, the accuracy of the segmentation result can be severely affected. To alleviate this problem, prior…

Computer Vision and Pattern Recognition · Computer Science 2021-04-01 Daoping Zhang , Lok Ming Lui

Obtaining high quality particle distribution representing clean geometry in pre-processing is essential for the simulation accuracy of the particle-based methods. In this paper, several level-set based techniques for cleaning up `dirty'…

Computational Engineering, Finance, and Science · Computer Science 2023-05-01 Yongchuan Yu , Yujie Zhu , Chi Zhang , Oskar J. Haidn , Xiangyu Hu

In this article, a new method for segmentation and restoration of images on two-dimensional surfaces is given. Active contour models for image segmentation are extended to images on surfaces. The evolving curves on the surfaces are…

Computer Vision and Pattern Recognition · Computer Science 2015-05-04 Heike Benninghoff , Harald Garcke

An inverse problem of identifying inhomogeneity or crack in the workpiece made of nonlinear magnetic material is investigated. To recover the shape from the local measurements, a piecewise constant level set algorithm is proposed. By means…

Mathematical Physics · Physics 2012-12-04 Xiangyin Kong , Zhengfang Zhang , Zhengda Huang

Limited data and low dose constraints are common problems in a variety of tomographic reconstruction paradigms which lead to noisy and incomplete data. Over the past few years sinogram denoising has become an essential pre-processing step…

Computer Vision and Pattern Recognition · Computer Science 2016-03-15 Faisal Mahmood , Nauman Shahid , Pierre Vandergheynst , Ulf Skoglund

In this work we consider a generalized bilevel optimization framework for solving inverse problems. We introduce fractional Laplacian as a regularizer to improve the reconstruction quality, and compare it with the total variation…

Image and Video Processing · Electrical Eng. & Systems 2020-06-24 Harbir Antil , Zichao Di , Ratna Khatri

Limited view tomographic reconstruction aims to reconstruct a tomographic image from a limited number of sinogram or projection views arising from sparse view or limited angle acquisitions that reduce radiation dose or shorten scanning…

Image and Video Processing · Electrical Eng. & Systems 2020-09-04 Bo Zhou , S. Kevin Zhou , James S. Duncan , Chi Liu

The paper studies an imaging problem in the diffusive ultrasound-modulated bioluminescence tomography with partial boundary measurement in an anisotropic medium. Assuming plane-wave modulation, we transform the imaging problem to an inverse…

Analysis of PDEs · Mathematics 2024-04-05 Tianyu Yang , Yang Yang

We propose a level set method to reconstruct unknown surfaces from point clouds, without assuming that the connections between points are known. We consider a variational formulation with a curvature constraint that minimizes the surface…

Numerical Analysis · Mathematics 2024-10-30 Silvia Preda , Matteo Semplice

This paper presents an uncalibrated deep neural network framework for the photometric stereo problem. For training models to solve the problem, existing neural network-based methods either require exact light directions or ground-truth…

Computer Vision and Pattern Recognition · Computer Science 2021-04-20 Berk Kaya , Suryansh Kumar , Carlos Oliveira , Vittorio Ferrari , Luc Van Gool

We present a regularization method to approach a solution of the pessimistic formulation of ill -posed bilevel problems . This allows to overcome the difficulty arising from the non uniqueness of the lower level problems solutions and…

Optimization and Control · Mathematics 2016-08-16 Maïtine Bergounioux , Mounir Haddou