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Illuminant estimation aims to infer scene illumination from image measurements despite intrinsic ambiguities between surface reflectance and lighting. Most existing methods operate on trichromatic RGB images and are therefore fundamentally…

Computer Vision and Pattern Recognition · Computer Science 2026-05-14 G. Dofri Vidarsson , Liying Lu , Sabine Süsstrunk

A conditional random field (CRF) model for cloud detection in ground based sky images is presented. We show that very high cloud detection accuracy can be achieved by combining a discriminative classifier and a higher order clique potential…

Image and Video Processing · Electrical Eng. & Systems 2019-06-19 Vijai T. Jayadevan , Jeffrey J. Rodriguez , Alexander D. Cronin

Estimating a scene's lighting is a very important task when compositing synthetic content within real environments, with applications in mixed reality and post-production. In this work we present a data-driven model that estimates an HDR…

Computer Vision and Pattern Recognition · Computer Science 2020-05-19 Vasileios Gkitsas , Nikolaos Zioulis , Federico Alvarez , Dimitrios Zarpalas , Petros Daras

In this paper a hybrid image defogging approach based on region segmentation is proposed to address the dark channel priori algorithm's shortcomings in de-fogging the sky regions. The preliminary stage of the proposed approach focuses on…

Image and Video Processing · Electrical Eng. & Systems 2020-07-14 Weixiang Li , Wei Jie , Somaiyeh MahmoudZadeh

The Sky Brightness Monitor (SBM) is an important instrument to measure the brightness level for the sky condition, which is a critical parameter for judging a site for solar coronal observations. In this paper we present an automatic method…

Solar and Stellar Astrophysics · Physics 2015-06-22 M. Y. Zhao , Y. Liu , A. Elmhamdi , A. S. Kordi , H. A. Al-trabulsy , X. F. Zhang , T. F. Song , S. Q. Liu , Y. D. Shen , Z. J. Tian , Y. H. Miao

We develop an unsupervised, nonparametric, and scalable statistical learning method for detection of unknown objects in noisy images. The method uses results from percolation theory and random graph theory. We present an algorithm that…

Statistics Theory · Mathematics 2018-07-16 Mikhail A. Langovoy , Olaf Wittich , Patrick Laurie Davies

The diffuse, unresolved sky provides most of the photons that the Hubble Space Telescope (HST) receives, yet remains poorly understood. HST Archival Legacy program SKYSURF aims to measure the 0.2-1.6 $\mu$m sky surface brightness (sky-SB)…

We present an algorithm capable of detecting diffuse, dim sources of any size in an astronomical image. These sources often defeat traditional methods for source finding, which expand regions around points of high intensity. Extended…

Instrumentation and Methods for Astrophysics · Physics 2016-01-05 T. Butler-Yeoman , M. Frean , C. P. Hollitt , D. W. Hogg , M. Johnston-Hollitt

A consensus-based optimization (CBO) algorithm, which enables derivative and mesh-free optimization, is presented to localize a bioluminescent source. The light propagation is modeled by the radiative transfer equation approximated by…

Quantitative Methods · Quantitative Biology 2024-11-04 Jan Friedrich , Sarah Schraven , Fabian Kiessling , Michael Herty

This paper presents a preliminary conceptual investigation into an environment representation that has constant space complexity with respect to the camera image space. This type of representation allows the planning algorithms of a mobile…

Robotics · Computer Science 2017-09-13 Jeffrey Kane Johnson

We implement an algorithm based on the weighted stacking of astronomical images that can combine different observations of the same region of the sky removing the interfering signals. We develop a C++ code that takes as input a set of…

Instrumentation and Methods for Astrophysics · Physics 2024-04-30 Giulia Murgia , Sofia Fatigoni

We present RESOLVE, a new algorithm for radio aperture synthesis imaging of extended and diffuse emission in total intensity. The algorithm is derived using Bayesian statistical inference techniques, estimating the surface brightness in the…

Instrumentation and Methods for Astrophysics · Physics 2016-02-03 H. Junklewitz , M. R. Bell , M. Selig , T. A. Enßlin

Traditional cosmic ray filtering algorithms used in X-ray imaging detectors aboard space telescopes perform event reconstruction based on the properties of activated pixels above a certain energy threshold, within 3x3 or 5x5 pixel sliding…

Atmosphere light value is a highly critical parameter in defogging algorithms that are based on an atmosphere scattering model. Any error in atmosphere light value will produce a direct impact on the accuracy of scattering computation and…

Computer Vision and Pattern Recognition · Computer Science 2017-01-13 Wenbo Zhang , Xiaorong Hou

Computational color constancy refers to the problem of computing the illuminant color so that the images of a scene under varying illumination can be normalized to an image under the canonical illumination. In this paper, we adopt a deep…

Computer Vision and Pattern Recognition · Computer Science 2016-08-30 Seoung Wug Oh , Seon Joo Kim

We present a new particle tracking software algorithm designed to accurately track the motion of low-contrast particles against a background with large variations in light levels. The method is based on a polynomial fit of the intensity…

Soft Condensed Matter · Physics 2009-11-13 Salman S. Rogers , Thomas A. Waigh , Xiubo Zhao , Jian R. Lu

Inverse rendering of outdoor scenes from unconstrained image collections is a challenging task, particularly illumination/albedo ambiguities and occlusion of the illumination environment (shadowing) caused by geometry. However, there are…

Computer Vision and Pattern Recognition · Computer Science 2024-07-31 James A. D. Gardner , Evgenii Kashin , Bernhard Egger , William A. P. Smith

This paper is concerned with the inverse scattering problem by an unbounded rough surface. A direct imaging method is proposed to reconstruct the rough surface from the scattered near-field Cauchy data generating by point sources and…

Numerical Analysis · Mathematics 2018-05-01 Xiaoli Liu , Bo Zhang , Haiwen Zhang

We describe a procedure for background subtracting Sloan Digital Sky Survey (SDSS) imaging that improves the resulting detection and photometry of large galaxies on the sky. Within each SDSS drift scan run, we mask out detected sources and…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 Michael R. Blanton , Eyal Kazin , Demitri Muna , Benjamin A. Weaver , Adrian Price-Whelan

The sensitivity of astronomical X-ray detectors is limited by the instrumental background. The background is especially important when observing low surface brightness sources that are critical for many of the science cases targeted by…

Instrumentation and Methods for Astrophysics · Physics 2022-08-18 D. R. Wilkins , S. W. Allen , E. D. Miller , M. Bautz , T. Chattopadhyay , R. Foster , C. E. Grant , S. Hermann , R. Kraft , R. G. Morris , P. Nulsen , G. Schellenberger