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We present a method of reliably extracting the flux of individual sources from sky maps in the presence of noise and a source population in which number counts are a steeply falling function of flux. The method is an extension of a standard…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 T. M. Crawford , E. R. Switzer , W. L. Holzapfel , C. L. Reichardt , D. P. Marrone , J. D. Vieira

Modern high-resolution images obtained with space observatories display extremely strong intensity variations across images on all spatial scales. Source extraction in such images with methods based on global thresholding may bring…

Instrumentation and Methods for Astrophysics · Physics 2017-11-15 Alexander Men'shchikov

The large number of microlensing events discovered towards the Galactic Bulge bears the promise to reconstruct the stellar mass function. The more interesting issue concerning the mass function is certainly to probe its low mass end.…

Astrophysics · Physics 2009-10-31 C. Alard

Image subtraction is essential for transient detection in time-domain astronomy. The point spread function (PSF), photometric scaling, and sky background generally vary with time and across the field-of-view for imaging data taken with…

Instrumentation and Methods for Astrophysics · Physics 2022-09-14 Lei Hu , Lifan Wang , Xingzhuo Chen , Jiawen Yang

In two-dimensional spectrographs, the optical distortions in the spatial and dispersion directions produce variations in the sub-pixel sampling of the background spectrum. Using knowledge of the camera distortions and the curvature of the…

Astrophysics · Physics 2009-12-08 Daniel D. Kelson

It is demonstrated that non-constant kernel solution, that can fit the spatial variations of the kernel can be obtained with minimum computing time. The CPU cost required with this new extension of the image subtraction method is almost the…

Astrophysics · Physics 2007-05-23 C. Alard

Spectroastrometry is a technique which has the potential to resolve flux distributions on scales of milliarcseconds. In this study, we examine the application of spectroastrometry to binary point sources which are spatially unresolved due…

Astrophysics · Physics 2009-11-10 John M. Porter , Rene D. Oudmaijer , Debbie Baines

We present a novel method for image anomaly detection, where algorithms that use samples drawn from some distribution of "normal" data, aim to detect out-of-distribution (abnormal) samples. Our approach includes a combination of encoder and…

Image and Video Processing · Electrical Eng. & Systems 2020-03-02 Nina Tuluptceva , Bart Bakker , Irina Fedulova , Anton Konushin

Blind source separation is a common processing tool to analyse the constitution of pixels of hyperspectral images. Such methods usually suppose that pure pixel spectra (endmembers) are the same in all the image for each class of materials.…

Methodology · Statistics 2022-10-03 Charlotte Revel , Yannick Deville , Véronique Achard , Xavier Briottet

Stacks of digital astronomical images are combined in order to increase image depth. The variable seeing conditions, sky background and transparency of ground-based observations make the coaddition process non-trivial. We present image…

Instrumentation and Methods for Astrophysics · Physics 2018-03-28 Barak Zackay , Eran O. Ofek

We present the results of applying new object classification techniques to difference images in the context of the Nearby Supernova Factory supernova search. Most current supernova searches subtract reference images from new images,…

Astrophysics · Physics 2009-06-23 S. Bailey , C. Aragon , R. Romano , R. C. Thomas , B. A. Weaver , D. Wong

We present a method to separate a single image captured under two illuminants, with different spectra, into the two images corresponding to the appearance of the scene under each individual illuminant. We do this by training a deep neural…

Computer Vision and Pattern Recognition · Computer Science 2019-04-24 Zhuo Hui , Ayan Chakrabarti , Kalyan Sunkavalli , Aswin C. Sankaranarayanan

This paper explores optimal methods for obtaining one-dimensional (1D) powder pattern intensities from two-dimensional (2D) planar detectors with good estimates of their standard deviations. We describe methods to estimate uncertainties…

Materials Science · Physics 2014-09-12 Xiaohao Yang , Pavol Juhas , Simon J. L. Billinge

(shortened) We determine the transformation matrix T that maps multiple images with resolved features onto one another and that is based on a Taylor-expanded lensing potential close to a point on the critical curve within our…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-16 Jenny Wagner , Nicolas Tessore

We present a method to estimate dense depth by optimizing a sparse set of points such that their diffusion into a depth map minimizes a multi-view reprojection error from RGB supervision. We optimize point positions, depths, and weights…

Computer Vision and Pattern Recognition · Computer Science 2021-06-30 Numair Khan , Min H. Kim , James Tompkin

There is widespread interest in estimating the fluorescence properties of natural materials in an image. However, the separation between reflected and fluoresced components is difficult, because it is impossible to distinguish reflected and…

Computer Vision and Pattern Recognition · Computer Science 2016-05-16 Henryk Blasinski , Joyce Farrell , Brian Wandell

We present an algorithm that uses the distribution of photon arrival times to distinguish speckles from incoherent sources, like planets and disks, in high contrast images. Using simulated data, we show that our approach can overcome the…

Instrumentation and Methods for Astrophysics · Physics 2019-10-09 Alex B. Walter , Clinton Bockstiegel , Timothy D. Brandt , Benjamin A. Mazin

In an effort to search for faint sources of emission over arbitrary timescales, we present a novel method for analyzing forced photometry light curves in difference imaging from optical surveys. Our method "ATLAS Clean'' or ATClean,…

In recent years, there has been a proliferation of wide-field sky surveys to search for a variety of transient objects. Using relatively short focal lengths, the optics of these systems produce undersampled stellar images often marred by a…

Astrophysics · Physics 2009-11-13 Fang Yuan , Carl W. Akerlof

Change in viewpoint is one of the major factors for variation in object appearance across different images. Thus, view-invariant object recognition is a challenging and important image understanding task. In this paper, we propose a method…

Computer Vision and Pattern Recognition · Computer Science 2017-05-15 Sina Lotfian , Hassan Foroosh