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Biological cells can release compounds into their direct environment, generally inhomogeneously over their cell membrane, after which the compounds spread by diffusion. In mathematical modelling and simulation of a collective of such cells,…

Numerical Analysis · Mathematics 2025-05-13 Qiyao Peng , Sander C. Hille

Diffusion models (DMs) have recently been introduced in image deblurring and exhibited promising performance, particularly in terms of details reconstruction. However, the diffusion model requires a large number of inference iterations to…

Computer Vision and Pattern Recognition · Computer Science 2023-09-26 Zheng Chen , Yulun Zhang , Ding Liu , Bin Xia , Jinjin Gu , Linghe Kong , Xin Yuan

We address the problem of discretizing continuous cosmological signals such as a galaxy distribution for further processing with Fast Fourier techniques. Discretizing, in particular representing continuous signals by discrete sets of sample…

Instrumentation and Methods for Astrophysics · Physics 2009-01-21 J. Jasche , F. S. Kitaura , T. A. Ensslin

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

The spatial and spectral degradation functions are critical to hyper- and multi-spectral image fusion. However, few work has been payed on the estimation of the degradation functions. To learn the spatial response function and the point…

Computer Vision and Pattern Recognition · Computer Science 2022-02-01 Ting Hu

This Point spread function (PSF) plays a crucial role in many computational imaging applications, such as shape from focus/defocus, depth estimation, and fluorescence microscopy. However, the mathematical model of the defocus process is…

Computer Vision and Pattern Recognition · Computer Science 2022-09-20 Renzhi He , Yan Zhuang , Boya Fu , Fei Liu

Strong gravitational lensing gives access to the total mass distribution of galaxies. It can unveil a great deal of information about the lenses dark matter content when combined with the study of the lenses light profile. However,…

Astrophysics of Galaxies · Physics 2017-08-02 Judith Biernaux , Pierre Magain , Clementine Hauret

Various biological cells secrete diffusing chemical compounds into their environment for communication purposes. Secretion usually takes place over the cell membrane in a spatially heterogeneous manner. Mathematical models of these…

Numerical Analysis · Mathematics 2025-11-20 Qiyao Peng , Sander C. Hille

Incoherently illuminated or luminescent objects give rise to a low-contrast speckle-like pattern when observed through a thin diffusive medium, as such a medium effectively convolves their shape with a speckle-like point spread function…

From the earth's crust to the human brain, remitted waves are used for sensing and imaging in a diverse range of diffusive media. Separating the source and detector increases the penetration depth of remitted light, yet rapidly decreases…

This paper introduces the expanded real numbers as an ordered subring of the hyperreal number field that does not contain any infinitesimals, and defines the set of all integrable functions from the real numbers to the expanded real…

General Mathematics · Mathematics 2021-10-01 Marcoen J. T. F. Cabbolet

Telescope arrays allow high-performance wide-field imaging systems to be built more quickly and at lower cost than conventional telescopes. Distributed aperture telescopes (the premier example of which is the Dragonfly Telephoto Array) are…

Instrumentation and Methods for Astrophysics · Physics 2022-09-16 Roberto G. Abraham , Pieter G. van Dokkum , Deborah M. Lokhorst , Seery Chen , Qing Liu , Michael L. Rice , E. Lynn Rice

Single-shot coherent diffractive imaging (CDI) using intense XUV and soft X-ray pulses holds the promise to deliver information on the three dimensional shape as well as the optical properties of nano-scale objects in a single diffraction…

Optics · Physics 2025-11-25 Paul Tuemmler , Julia Apportin , Thomas Fennel , Christian Peltz

Most research on astrophysical lensing has been conducted using the geometric optics framework, where there exists a clear concept of lensing images. However, wave optics effects can be important for coherent sources, e.g. pulsars, fast…

Instrumentation and Methods for Astrophysics · Physics 2024-10-29 Xun Shi

Recent advances in implicit neural representations have achieved impressive results by sampling and fusing individual points along sampling rays in the sampling space. However, due to the explosively growing sampling space, finely…

Computer Vision and Pattern Recognition · Computer Science 2024-01-12 Yuhan Ding , Fukun Yin , Jiayuan Fan , Hui Li , Xin Chen , Wen Liu , Chongshan Lu , Gang YU , Tao Chen

While diffusion models excel at generating continuous data such as images, adapting them to discrete tasks has relied on indirect approaches that either operate in continuous embedding spaces or use token masking mechanisms, both of which…

Computer Vision and Pattern Recognition · Computer Science 2025-11-25 Xiao Li , Jiaqi Zhang , Shuxiang Zhang , Tianshui Chen , Liang Lin , Guangrun Wang

General properties of linear propagation of discretized light in homogeneous and curved waveguide arrays are comprehensively investigated and compared to those of paraxial diffraction in continuous media. In particular, general laws…

Optics · Physics 2015-05-14 S. Longhi

We report a diffuse Maxwellian illumination scheme for wide-field retinal laser Doppler holography. Inserting an engineered diffuser in the illumination arm transforms a spatially concentrated near-infrared laser focus into an angularly…

An active learning algorithm for the classification of high-dimensional images is proposed in which spatially-regularized nonlinear diffusion geometry is used to characterize cluster cores. The proposed method samples from estimated cluster…

Machine Learning · Computer Science 2019-11-07 James M. Murphy

Point-spread-function (PSF) engineering is a powerful computational imaging techniques wherein a custom phase mask is integrated into an optical system to encode additional information into captured images. Used in combination with deep…

Computer Vision and Pattern Recognition · Computer Science 2023-03-31 Sachin Shah , Sakshum Kulshrestha , Christopher A. Metzler