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The knowledge of the exact structure of the optical system PSF enables a high-quality image reconstruction in fluorescence microscopy. Accurate PSF models account for the vector nature of light and the phase and amplitude modifications.…

The point spread function (PSF) reflects states of a telescope and plays an important role in development of data processing methods, such as PSF based astrometry, photometry and image restoration. However, for wide field small aperture…

Instrumentation and Methods for Astrophysics · Physics 2021-07-07 Peng Jia , Xuebo Wu , Zhengyang Li , Bo Li , Weihua Wang , Qiang Liu , Adam Popowicz

In many image processing tasks it occurs that pixels or blocks of pixels are missing or lost in only some channels. For example during defective transmissions of RGB images, it may happen that one or more blocks in one color channel are…

Image and Video Processing · Electrical Eng. & Systems 2022-09-19 Frank Sippel , Jürgen Seiler , André Kaup

Image degradation due to atmospheric turbulence is common while capturing images at long ranges. To mitigate the degradation due to turbulence which includes deformation and blur, we propose a generative single frame restoration algorithm…

Computer Vision and Pattern Recognition · Computer Science 2020-07-24 Chun Pong Lau , Hossein Souri , Rama Chellappa

In this paper, we propose a novel formulation to extend CNNs to two-dimensional (2D) manifolds using orthogonal basis functions, called Zernike polynomials. In many areas, geometric features play a key role in understanding scientific…

Computer Vision and Pattern Recognition · Computer Science 2023-05-12 Zhiyu Sun , Ethan Rooke , Jerome Charton , Yusen He , Jia Lu , Stephen Baek

Incorporating diffusion models in the image compression domain has the potential to produce realistic and detailed reconstructions, especially at extremely low bitrates. Previous methods focus on using diffusion models as expressive…

Image and Video Processing · Electrical Eng. & Systems 2024-10-10 Lucas Relic , Roberto Azevedo , Markus Gross , Christopher Schroers

Numerical simulation of atmospheric turbulence is one of the biggest bottlenecks in developing computational techniques for solving the inverse problem in long-range imaging. The classical split-step method is based upon numerical wave…

Image and Video Processing · Electrical Eng. & Systems 2022-10-14 Nicholas Chimitt , Xingguang Zhang , Zhiyuan Mao , Stanley H. Chan

The partial derivatives and Laplacians of the Zernike circle polynomials occur in various places in the literature on computational optics. In a number of cases, the expansion of these derivatives and Laplacians in the circle polynomials…

Mathematical Physics · Physics 2015-06-19 Augustus J. E. M Janssen

To directly image Earth-like planets, contrast levels of 10^-8 - 10^-10 are required. The next generation of instruments will need wavefront control below the nanometer level to achieve these goals. The Zernike wavefront sensor (ZWFS) is a…

Instrumentation and Methods for Astrophysics · Physics 2025-10-01 M. Darcis , S. Y. Haffert , V. Chambouleyron , D. S. Doelman , P. J. de Visser , M. A. Kenworthy

A unified method for three-dimensional reconstruction of objects from transmission images collected at multiple illumination directions is described. The method may be applicable to experimental conditions relevant to absorption-based,…

Medical Physics · Physics 2022-12-07 Timur E. Gureyev , Hamish G. Brown , Harry M. Quiney , Leslie J. Allen

Next-generation radio interferometric telescopes will exhibit non-coplanar baseline configurations and wide field-of-views, inducing a w-modulation of the sky image, which in turn induces the spread spectrum effect. We revisit the impact of…

Instrumentation and Methods for Astrophysics · Physics 2013-11-27 L. Wolz , J. D. McEwen , F. B. Abdalla , R. E. Carrillo , Y. Wiaux

With the improvement of the pattern recognition and feature extraction of Deep Neural Networks (DPNNs), image-based design and optimization have been widely used in multidisciplinary researches. Recently, a Reconstructive Neural Network…

Other Computer Science · Computer Science 2019-06-04 Yu Li , Hu Wang , Wenquan Shuai , Honghao Zhang , Yong Peng

Atmospheric turbulence can significantly degrade the quality of images acquired by long-range imaging systems by causing spatially and temporally random fluctuations in the index of refraction of the atmosphere. Variations in the refractive…

Image and Video Processing · Electrical Eng. & Systems 2022-07-08 Rajeev Yasarla , Vishal M. Patel

Image restoration aims to enhance low quality images, producing high quality images that exhibit natural visual characteristics and fine semantic attributes. Recently, the diffusion model has emerged as a powerful technique for image…

Computer Vision and Pattern Recognition · Computer Science 2024-07-23 Jiangtong Tan , Feng Zhao

The theory of degenerate parabolic equations of the forms \[ u_t=(\Phi(u_x))_{x} \quad {\rm and} \quad v_{t}=(\Phi(v))_{xx} \] is used to analyze the process of contour enhancement in image processing, based on the evolution model of…

Dynamical Systems · Mathematics 2007-05-23 G. I. Barenblatt , J. L. Vazquez

We analyze the aliasing phenomenon for digital Fresnel hologram with an enhanced numerical aperture (NA). The enhanced-NA digital hologram acquired computationally or optically at a closer distance from the object has an aliased fringe…

Optics · Physics 2020-05-28 Byung Gyu Chae

The fundamental problem of optical wave propagation is the determination of the field at an observation point, given a disturbance specified over some finite aperture. In both vacuum and inhomogeneous media, the solution of this problem is…

Analysis of PDEs · Mathematics 2007-05-23 Peng Li

We implement an efficient method of computation of two dimensional Fourier-type integrals based on approximation of the integrand by Gaussian radial basis functions, which constitute a standard tool in approximation theory. As a result, we…

Numerical Analysis · Mathematics 2022-02-07 A. Martinez-Finkelshtein , D. Ramos-Lopez , D. R. Iskander

We present a liquid crystal method of correcting the phase of an aberrated wavefront using a spatial light modulator. A simple and efficient lab model has been demonstrated for wavefront correction. The crux of a wavefront correcting system…

Instrumentation and Methods for Astrophysics · Physics 2009-10-11 Akondi Vyas , M. B. Roopashree , Ravinder Kumar Banyal , B. Raghavendra Prasad

The optics of any camera degrades the sharpness of photographs, which is a key visual quality criterion. This degradation is characterized by the point-spread function (PSF), which depends on the wavelengths of light and is variable across…

Image and Video Processing · Electrical Eng. & Systems 2022-08-02 Thomas Eboli , Jean-Michel Morel , Gabriele Facciolo
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