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We investigate the reconstruction problem of limited angle tomography. Such problems arise naturally in applications like digital breast tomosynthesis, dental tomography, electron microscopy etc. Since the acquired tomographic data is…

Numerical Analysis · Mathematics 2011-09-05 Jürgen Frikel

In this paper we present a differential approach to photo-polarimetric shape estimation. We propose several alternative differential constraints based on polarisation and photometric shading information and show how to express them in a…

Computer Vision and Pattern Recognition · Computer Science 2017-08-28 Silvia Tozza , William A. P. Smith , Dizhong Zhu , Ravi Ramamoorthi , Edwin R. Hancock

This paper proposes a level set-based method for optimizing shell structures with large design changes in shape and topology. Conventional shell optimization methods, whether parametric or nonparametric, often only allow limited design…

Computational Engineering, Finance, and Science · Computer Science 2024-08-29 Hiroki Kobayashi , Katsuya Nomura , Yuqing Zhou , Masato Tanaka , Atsushi Kawamoto , Tsuyoshi Nomura

In this paper we propose a new approach for tomographic reconstruction with spatially varying regularization parameter. Our work is based on the SA-TV image restoration model proposed in [3] where an automated parameter selection rule for…

Numerical Analysis · Mathematics 2018-11-27 Yiqiu Dong , Carola-Bibiane Schönlieb

Problems in differentiable rendering often involve optimizing scene parameters that cause motion in image space. The gradients for such parameters tend to be sparse, leading to poor convergence. While existing methods address this sparsity…

Graphics · Computer Science 2025-03-31 Ishit Mehta , Manmohan Chandraker , Ravi Ramamoorthi

In this study, we investigate the inverse source problem arising in bioluminescence tomography, the objective of which is to reconstruct both the support and the intensity of an internal light source from boundary measurements governed by…

Numerical Analysis · Mathematics 2025-11-25 Qianqian Wu , Rongfang Gong , Wei Gong , Ziyi Zhang , Shengfeng Zhu

We study multilevel techniques, commonly used in PDE multigrid literature, to solve structured optimization problems. For a given hierarchy of levels, we formulate a coarse model that approximates the problem at each level and provides a…

Optimization and Control · Mathematics 2025-05-19 Ferdinand Vanmaele , Yara Elshiaty , Stefania Petra

Shape optimization involves the minimization of a cost function defined over a set of shapes, often governed by a partial differential equation (PDE). In the absence of closed-form solutions, one relies on numerical methods to approximate…

Numerical Analysis · Mathematics 2025-02-21 Eloi Martinet , Leon Bungert

We introduce a new algorithm for complex image reconstruction with separate regularization of the image magnitude and phase. This optimization problem is interesting in many different image reconstruction contexts, although is nonconvex and…

Signal Processing · Electrical Eng. & Systems 2020-12-17 Yunsong Liu , Justin P. Haldar

The main difficulty in high-dimensional anomaly detection tasks is the lack of anomalous data for training. And simply collecting anomalous data from the real world, common distributions, or the boundary of normal data manifold may face the…

Computer Vision and Pattern Recognition · Computer Science 2021-04-27 Songmin Dai , Jide Li , Lu Wang , Congcong Zhu , Yifan Wu , Xiaoqiang Li

Manifold learning aims to discover and represent low-dimensional structures underlying high-dimensional data while preserving critical topological and geometric properties. Existing methods often fail to capture local details with global…

Machine Learning · Computer Science 2025-05-08 Ren Wang , Pengcheng Zhou

Variational level set method has become a powerful tool in image segmentation due to its ability to handle complex topological changes and maintain continuity and smoothness in the process of evolution. However its evolution process can be…

Computer Vision and Pattern Recognition · Computer Science 2024-06-27 Fanghui Song , Jiebao Sun , Shengzhu Shi , Zhichang Guo , Dazhi Zhang

We propose a new strategy to bridge point cloud denoising and surface reconstruction by alternately updating the denoised point clouds and the reconstructed surfaces. In Poisson surface reconstruction, the implicit function is generated by…

Graphics · Computer Science 2023-08-25 Dong Xiao , Zuoqiang Shi , Bin Wang

Convex optimization problems arising in applications often have favorable objective functions and complicated constraints, thereby precluding first-order methods from being immediately applicable. We describe an approach that exchanges the…

Optimization and Control · Mathematics 2016-02-05 Aleksandr Y. Aravkin , James V. Burke , Dmitriy Drusvyatskiy , Michael P. Friedlander , Scott Roy

Level-set methods for convex optimization are predicated on the idea that certain problems can be parameterized so that their solutions can be recovered as the limiting process of a root-finding procedure. This idea emerges time and again…

Optimization and Control · Mathematics 2020-05-19 Ron Estrin , Michael P. Friedlander

Ptychography is a powerful computational imaging technique that transforms a collection of low-resolution images into a high-resolution sample reconstruction. Unfortunately, algorithms that are currently used to solve this reconstruction…

In this paper, we introduce a total variation based variational model for denoising wrapped phase images. Our model improves on former methods by preserving discontinuities of the phase map and enforcing the fundamental Pythagorean…

Numerical Analysis · Mathematics 2023-04-07 Ivan May-Cen , Ricardo Legarda-Saenz , Carlos Brito-Loeza

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

Many surface reconstruction methods incorporate normal integration, which is a process to obtain a depth map from surface gradients. In this process, the input may represent a surface with discontinuities, e.g., due to self-occlusion. To…

Computer Vision and Pattern Recognition · Computer Science 2024-04-05 Hyomin Kim , Yucheol Jung , Seungyong Lee

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