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Cryo-Electron Microscopy (Cryo-EM) is a Nobel prize-winning technology for determining the 3D structure of particles at near-atomic resolution. A fundamental step in the recovering of the 3D single-particle structure is to align its 2D…

Image and Video Processing · Electrical Eng. & Systems 2021-01-12 Koby Bibas , Gili Weiss-Dicker , Dana Cohen , Noa Cahan , Hayit Greenspan

Calibration of devices with different modalities is a key problem in robotic vision. Regular spatial objects, such as planes, are frequently used for this task. This paper deals with the automatic detection of ellipses in camera images, as…

Computer Vision and Pattern Recognition · Computer Science 2020-02-25 Levente Hajder , Tekla Tóth , Zoltán Pusztai

Disordered structures producing a non-iridescent color impression have been shown to feature a spherically shaped Fourier transform of their refractive-index distribution. We determine the direction and efficiency of scattering from thin…

We demonstrate a method for filtering images defined on curved surfaces embedded in 3D. Applications are noise removal and the creation of artistic effects. Our approach relies on in-surface diffusion: we formulate Weickert's edge/coherence…

Numerical Analysis · Mathematics 2014-04-08 Emma Naden , Thomas März , Colin B. Macdonald

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

Three-dimensional particle reconstruction with limited two-dimensional projections is an under-determined inverse problem that the exact solution is often difficult to be obtained. In general, approximate solutions can be obtained by…

Image and Video Processing · Electrical Eng. & Systems 2021-09-14 Qi Gao , Shaowu Pan , Hongping Wang , Runjie Wei , Jinjun Wang

Three-dimensional phase contrast imaging of multiply-scattering samples in X-ray and electron microscopy is extremely challenging, due to small numerical apertures, the unavailability of wavefront shaping optics, and the highly nonlinear…

Computational Physics · Physics 2021-06-02 Philipp M Pelz , Hamish G Brown , Jim Ciston , Scott D Findlay , Yaqian Zhang , Mary Scott , Colin Ophus

In this paper we propose an algorithm for aligning three-dimensional objects when represented as density maps, motivated by applications in cryogenic electron microscopy. The algorithm is based on minimizing the 1-Wasserstein distance…

Image and Video Processing · Electrical Eng. & Systems 2024-03-13 Amit Singer , Ruiyi Yang

We propose three fast algorithms for solving the inverse problem of the thermoacoustic tomography corresponding to certain acquisition geometries. Two of these methods are designed to process the measurements done with point-like detectors…

Analysis of PDEs · Mathematics 2011-02-08 Leonid Kunyansky

We analyze multi-bounce propagation of light in an unknown hidden volume and demonstrate that the reflected light contains sufficient information to recover the 3D structure of the hidden scene. We formulate the forward and inverse theory…

We present a theoretical and exact analysis of the bispectrum of projected galaxy catalogues. The result can be generalized to evaluate the projection in spherical harmonics of any 3D bispectrum and therefore has applications to cosmic…

Astrophysics · Physics 2015-06-24 Licia Verde , Alan F. Heavens , Sabino Matarrese

We present the first three-dimensional theoretical model of microparticle-assisted super-resolution imaging, enabling accurate simulation of virtual image formation. The model reveals that accounting for partial spatial coherence of…

This paper introduces a method of calculating and rendering shapes in a non-Euclidean 2D space. In order to achieve this, we developed a physics and graphics engine that uses hyperbolic trigonometry to calculate and subsequently render the…

Graphics · Computer Science 2019-08-13 Daniil Osudin , Christopher Child , Yang-Hui He

Atmospheric turbulence in long-range imaging significantly degrades the quality and fidelity of captured scenes due to random variations in both spatial and temporal dimensions. These distortions present a formidable challenge across…

Computer Vision and Pattern Recognition · Computer Science 2024-10-02 Zhicheng Zou , Nantheera Anantrasirichai

Recently, multiple formulations of vision problems as probabilistic inversions of generative models based on computer graphics have been proposed. However, applications to 3D perception from natural images have focused on low-dimensional…

Computer Vision and Pattern Recognition · Computer Science 2014-07-08 Tejas D. Kulkarni , Vikash K. Mansinghka , Pushmeet Kohli , Joshua B. Tenenbaum

In this work we present an extension of the Virtual Element Method with curved edges for the numerical approximation of the second order wave equation in a bidimensional setting. Curved elements are used to describe the domain boundary, as…

Numerical Analysis · Mathematics 2021-06-14 Franco Dassi , Alessio Fumagalli , Ilario Mazzieri , Anna Scotti , Giuseppe Vacca

This contribution introduces a novel signal extrapolation algorithm and its application to image error concealment. The signal extrapolation is carried out by iteratively generating a model of the signal suffering from distortion. Thereby,…

Image and Video Processing · Electrical Eng. & Systems 2022-07-15 Jürgen Seiler , André Kaup

Photoemission orbital tomography provides direct access from laboratory measurements to the real-space molecular orbitals of well-ordered organic semiconductor layers. Specifically, the application of phase retrieval algorithms to…

Materials Science · Physics 2024-04-29 Thi Lan Dinh , G. S. Matthijs Jansen , D. Russell Luke , Wiebke Bennecke , Stefan Mathias

Diffusion models have become a popular approach for image generation and reconstruction due to their numerous advantages. However, most diffusion-based inverse problem-solving methods only deal with 2D images, and even recently published 3D…

Image and Video Processing · Electrical Eng. & Systems 2023-09-04 Suhyeon Lee , Hyungjin Chung , Minyoung Park , Jonghyuk Park , Wi-Sun Ryu , Jong Chul Ye

Reflection high-energy electron diffraction (RHEED) is a powerful tool for characterizing crystal surface structures. However, the setup geometry leads to distorted and complicated patterns, which are not straightforward to link to the…

Materials Science · Physics 2022-08-25 Chong Liu , Kai Chang , Ke Zou