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This work develops new numerical methods for the solution of the tomography problem in domains with reflecting obstacles. We compare the solution's performance for Lambertian reflection, for classical tomography with ubroken rays and for…

Numerical Analysis · Mathematics 2012-09-04 Kamen Lozev

We study numerical methods of tomography in domains with a reflecting obstacle. It will be shown that tomography with sets containing both broken rays, i.e. rays reflecting at the obstacle, as well as unbroken rays, has a smaller error…

Numerical Analysis · Mathematics 2012-02-14 Kamen Lozev

Optical diffraction tomography relies on solving an inverse scattering problem governed by the wave equation. Classical reconstruction algorithms are based on linear approximations of the forward model (Born or Rytov), which limits their…

Computational Engineering, Finance, and Science · Computer Science 2017-09-01 Emmanuel Soubies , Thanh-An Pham , Michael Unser

Photometric Stereo methods seek to reconstruct the 3d shape of an object from motionless images obtained with varying illumination. Most existing methods solve a restricted problem where the physical reflectance model, such as Lambertian…

Computer Vision and Pattern Recognition · Computer Science 2021-10-06 Ofer Bartal , Nati Ofir , Yaron Lipman , Ronen Basri

This paper aims at reviewing and analysing the method of reflections. The latter is an iterative procedure designed to linear boundary value problems set in multiply connected domains. Being based on a decomposition of the domain boundary,…

Analysis of PDEs · Mathematics 2021-06-25 Philippe Laurent , Guillaume Legendre , Julien Salomon

When imaging through a semi-reflective medium such as glass, the reflection of another scene can often be found in the captured images. It degrades the quality of the images and affects their subsequent analyses. In this paper, a novel deep…

Image and Video Processing · Electrical Eng. & Systems 2022-08-11 Tingtian Li , Yuk-Hee Chan , Daniel P. K. Lun

We introduce a novel reflection-mode diffraction tomography technique that enables simultaneous recovery of forward and backward scattering information for high-resolution 3D refractive index reconstruction. Our technique works by imaging a…

Optics · Physics 2025-02-12 Tongyu Li , Jiabei Zhu , Yi Shen , Lei Tian

We use the Landweber method for numerical simulations for the multiwave tomography problem with a reflecting boundary and compare it with the averaged time reversal method. We also analyze the rate of convergence and the dependence on the…

Analysis of PDEs · Mathematics 2016-04-21 Plamen Stefanov , Yang Yang

Augmented Lagrangian method (also called as method of multipliers) is an important and powerful optimization method for lots of smooth or nonsmooth variational problems in modern signal processing, imaging, optimal control and so on.…

Optimization and Control · Mathematics 2021-08-31 Hongpeng Sun

Recently, it has become evident that submodularity naturally captures widely occurring concepts in machine learning, signal processing and computer vision. Consequently, there is need for efficient optimization procedures for submodular…

Machine Learning · Computer Science 2013-11-19 Stefanie Jegelka , Francis Bach , Suvrit Sra

Specular reflections pose a significant challenge for object segmentation, as their sharp intensity transitions often mislead both conventional algorithms and deep learning based methods. However, as the specular reflection must lie on the…

Image and Video Processing · Electrical Eng. & Systems 2026-02-26 Katja Kossira , Yunxuan Zhu , Jürgen Seiler , André Kaup

Beamforming in ultrasound imaging has significant impact on the quality of the final image, controlling its resolution and contrast. Despite its low spatial resolution and contrast, delay-and-sum is still extensively used nowadays in…

Computer Vision and Pattern Recognition · Computer Science 2016-05-20 Teodora Szasz , Adrian Basarab , Denis Kouamé

Recent advancements in quantum computing and quantum-inspired algorithms have sparked renewed interest in binary optimization. These hardware and software innovations promise to revolutionize solution times for complex problems. In this…

Various numerical methods exist for obtaining the radiances inside a canopy of leaves above a partly reflecting ground. In view of testing the accuracy of these diverse methods, it is desirable to have at one's disposal non-trivial models…

Computational Physics · Physics 2007-05-23 Antoine Royer , Sophie Royer

We present a novel approach for the inverse problem in electrical impedance tomography based on regularized quadratic regression. Our contribution introduces a new formulation for the forward model in the form of a nonlinear integral…

Geophysics · Physics 2012-05-29 Nick Polydorides , Alireza Aghasi , Eric L. Miller

Denoising diffusion models have recently emerged as the predominant paradigm for generative modelling on image domains. In addition, their extension to Riemannian manifolds has facilitated a range of applications across the natural…

Machine Learning · Computer Science 2023-11-10 Nic Fishman , Leo Klarner , Emile Mathieu , Michael Hutchinson , Valentin de Bortoli

Twenty years ago the anti-reflective numerical boundary conditions (BCs) were introduced in a context of signal processing and imaging, for increasing the quality of the reconstruction of a blurred signal/image contaminated by noise and for…

Numerical Analysis · Mathematics 2024-05-31 Ercília Sousa , Cristina Tablino-Possio , Rolf Krause , Stefano Serra-Capizzano

We propose a novel iterative numerical method to solve the three-dimensional inverse obstacle scattering problem of recovering the shape of the obstacle from far-field measurements. To address the inherent ill-posed nature of the inverse…

Numerical Analysis · Mathematics 2024-04-18 Junqing Chen , Bangti Jin , Haibo Liu

Photometric stereo (PS) techniques nowadays remain constrained to an ideal laboratory setup where modeling and calibration of lighting is amenable. To eliminate such restrictions, we propose an efficient principled variational approach to…

Computer Vision and Pattern Recognition · Computer Science 2019-08-29 Bjoern Haefner , Zhenzhang Ye , Maolin Gao , Tao Wu , Yvain Quéau , Daniel Cremers

The recent development of spectral method has been praised for its high-order convergence in simulating complex physical problems. The combination of embedded boundary method and spectral method becomes a mainstream way to tackle…

Numerical Analysis · Mathematics 2018-03-08 Po-Yi Wu , Cheng-Hong Robert Kao , Tony Wen-Hann Sheu
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