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Optical coherence tomography (OCT) is a powerful and noninvasive method for retinal imaging. In this paper, we introduce a fast segmentation method based on a new variant of spectral graph theory named diffusion maps. The research is…

Computer Vision and Pattern Recognition · Computer Science 2012-10-09 Raheleh Kafieh , Hossein Rabbani , Michael D. Abramoff , Milan Sonka

For the rendering of multiple scattering effects in participating media, methods based on the diffusion approximation are an extremely efficient alternative to Monte Carlo path tracing. However, in sufficiently transparent regions,…

Graphics · Computer Science 2014-04-01 David Koerner , Jamie Portsmouth , Filip Sadlo , Thomas Ertl , Bernd Eberhardt

Photon transport through a diffusing slab can be described by the radiative transfer equation (RTE). When the slab is highly scattering and weakly absorbing, the RTE simplifies to the diffusion equation. In this paper, an inverse diffusion…

We propose a multiscale approach for an elliptic multiscale setting with general unstructured diffusion coefficients that is able to achieve high-order convergence rates with respect to the mesh parameter and the polynomial degree. The…

Numerical Analysis · Mathematics 2020-09-03 Roland Maier

Image-generative artificial intelligence (AI) has garnered significant attention in recent years. In particular, the diffusion model, a core component of generative AI, produces high-quality images with rich diversity. In this study, we…

Computer Vision and Pattern Recognition · Computer Science 2024-09-13 Sho Ozaki , Shizuo Kaji , Toshikazu Imae , Kanabu Nawa , Hideomi Yamashita , Keiichi Nakagawa

Image inpainting consists of filling holes or missing parts of an image. Inpainting face images with symmetric characteristics is more challenging than inpainting a natural scene. None of the powerful existing models can fill out the…

Computer Vision and Pattern Recognition · Computer Science 2023-01-10 MohammadReza Naderi , MohammadHossein Givkashi , Nader Karimi , Shahram Shirani , Shadrokh Samavi

In this paper, we study the mathematical imaging problem of optical diffraction tomography (ODT) for the scenario of a microscopic rigid particle rotating in a trap created, for instance, by acoustic or optical forces. Under the influence…

Neural posterior estimation (NPE), a simulation-based computational approach for Bayesian inference, has shown great success in approximating complex posterior distributions. Existing NPE methods typically rely on normalizing flows, which…

Machine Learning · Statistics 2025-03-14 Tianyu Chen , Vansh Bansal , James G. Scott

We present an algorithm to estimate fast and accurate depth maps from light fields via a sparse set of depth edges and gradients. Our proposed approach is based around the idea that true depth edges are more sensitive than texture edges to…

Computer Vision and Pattern Recognition · Computer Science 2021-07-08 Numair Khan , Min H. Kim , James Tompkin

We provide a representation result of parabolic semi-linear PD-Es, with polynomial nonlinearity, by branching diffusion processes. We extend the classical representation for KPP equations, introduced by Skorokhod (1964), Watanabe (1965) and…

Probability · Mathematics 2016-03-08 Pierre Henry-Labordere , Nadia Oudjane , Xiaolu Tan , Nizar Touzi , Xavier Warin

We consider the inverse problem of denoising an image where each point (pixel) is an element of a target set, which we refer to as a target-valued image. The target sets considered are either (i) a closed convex set of Euclidean space or…

Numerical Analysis · Mathematics 2018-06-20 Braxton Osting , Dong Wang

We present a new mimetic finite difference method for diffusion problems that converges on grids with \textit{curved} (i.e., non-planar) faces. Crucially, it gives a symmetric discrete problem that uses only one discrete unknown per curved…

Numerical Analysis · Mathematics 2023-07-19 Silvano Pitassi , Riccardo Ghiloni , Igor Petretti , Francesco Trevisan , Ruben Specogna

Compressed sensing Synthetic Aperture Radar (SAR) image formation, formulated as an inverse problem and solved with traditional iterative optimization methods can be very computationally expensive. We investigate the use of denoising…

Image and Video Processing · Electrical Eng. & Systems 2025-04-25 Odysseas Pappas , Perla Mayo , Andrew Austin , Alin Achim

In this work, we propose a new semi-Lagrangian (SL) finite difference scheme for nonlinear advection-diffusion problems. To ensure conservation, which is fundamental for achieving physically consistent solutions, the governing equations are…

Numerical Analysis · Mathematics 2025-11-05 Silvia Preda , Walter Boscheri , Matteo Semplice , Maurizio Tavelli

In this article we propose a generalization of the theory of diffusion approximation for random ODE to a nonlinear system of random Schr\"{o}dinger equations. This system arises in the study of pulse propagation in randomly birefringent…

Analysis of PDEs · Mathematics 2012-12-14 A. de Bouard , M. Gazeau

We present a general mechanism to establish the existence of diffusing orbits in a large class of nearly integrable Hamiltonian systems. Our approach relies on successive applications of the `outer dynamics' along homoclinic orbits to a…

Dynamical Systems · Mathematics 2017-04-26 Marian Gidea , Rafael de la Llave , Tere Seara

Diffusion models have recently shown considerable potential in solving Bayesian inverse problems when used as priors. However, sampling from the resulting denoising posterior distributions remains a challenge as it involves intractable…

Machine Learning · Statistics 2024-12-25 Badr Moufad , Yazid Janati , Lisa Bedin , Alain Durmus , Randal Douc , Eric Moulines , Jimmy Olsson

We consider the quantum inverse scattering method for several mixed integrable models based on the rational SU(N) R-matrix with general toroidal boundary conditions. This includes systems whose Hilbert spaces are invariant by the discrete…

Exactly Solvable and Integrable Systems · Physics 2009-11-10 G. A. P. Ribeiro , M. J. Martins

Recent advances in diffusion models have enabled the creation of deceptively real images, posing significant security risks when misused. In this study, we empirically show that different timesteps of DDIM inversion reveal varying subtle…

Computer Vision and Pattern Recognition · Computer Science 2025-07-29 Yixin Wu , Feiran Zhang , Tianyuan Shi , Ruicheng Yin , Zhenghua Wang , Zhenliang Gan , Xiaohua Wang , Changze Lv , Xiaoqing Zheng , Xuanjing Huang

We propose SymDiff, a method for constructing equivariant diffusion models using the framework of stochastic symmetrisation. SymDiff resembles a learned data augmentation that is deployed at sampling time, and is lightweight,…

Machine Learning · Computer Science 2025-03-04 Leo Zhang , Kianoosh Ashouritaklimi , Yee Whye Teh , Rob Cornish