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In this paper we test the astrometric precision of VLT/FORS2 observations using a serie of CCD frames taken in Galactic bulge area. A special reduction method based on symmetrization of reference fields was used to reduce the atmospheric…

Astrophysics · Physics 2009-11-11 Petro F. Lazorenko

Radio-interferometric arrays require very precise calibration to detect the Epoch of Reionization 21-cm signal. A remarkably complete and accurate sky model is therefore needed in the patches of the sky used to perform the calibration.…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-13 Khandakar Md Asif Elahi , Samir Choudhuri , Nirupam Roy , Md Rashid , Philip Bull , Dharam Vir Lal

We consider imaging of fast moving small objects in space, such as low earth orbit satellites, which are also rotating around a fixed axis. The imaging system consists of ground based, asynchronous sources of radiation and several passive…

Signal Processing · Electrical Eng. & Systems 2021-11-03 Matan Leibovich , George Papanicolaou , Chrysoula Tsogka

The MARS scanner is designed for the x-ray spectroscopic study of samples with the aid of computer tomography methods. Computer tomography allows the reconstruction of slices of an investigated sample using a set of shadow projections…

High dynamic range (HDR) imaging is a highly challenging task since a large amount of information is lost due to the limitations of camera sensors. For HDR imaging, some methods capture multiple low dynamic range (LDR) images with altering…

Computer Vision and Pattern Recognition · Computer Science 2023-08-23 Haesoo Chung , Nam Ik Cho

Residuals of a conventional plate adjustment of 5,687 plates of the Second Cape Photographic Catalogue (CPC2) using the Southern Reference Star (SRS) Catalog were analyzed to search for systematic errors depending on the location of the…

Astrophysics · Physics 2016-08-30 N. Zacharias

We present high-resolution HI data obtained using the Australia Telescope Compact Array to resolve the near/far distance ambiguities towards a sample of compact HII regions from the Red MSX Source (RMS) survey. The high resolution data are…

We present a new algorithm designed to improve the signal to noise ratio (SNR) of point and extended source detections in direct imaging data. The novel part of our method is that it finds the linear combination of the science images that…

Imaging through complex scattering media is severely limited by aberrations and scattering which obscure images and reduce resolution. Confocal and temporal gatings partly filter out multiple scattering but are severely degraded by…

Optics · Physics 2026-05-18 Yiwen Zhang , Minh Dinh , Zeyu Wang , Tianhao Zhang , Tianhang Chen , Chia Wei Hsu

In this paper a homomorphic filtering scheme is proposed to improve the estimation of the planet/star radius ratio in astronomical transit signals. The idea is to reduce the effect of the short-term earth atmosphere variations. A two-step…

Instrumentation and Methods for Astrophysics · Physics 2017-10-03 Rodrigo Mahu , Patricio Rojo , Ali Dehghan Firoozabadi , Ismael Soto , Elyar Sedaghati , Nestor Becerra Yoma

Motion during image acquisition can cause image degradation in all medical imaging modalities. This is particularly relevant in 2-D ultrasound imaging, since out-of-plane motion can only be compensated for movements smaller than elevational…

Medical Physics · Physics 2019-02-07 S. Harput , K. Christensen-Jeffries , J. Brown , J. Zhu , G. Zhang , R. J. Eckersley , C. Dunsby , M-X. Tang

We present a study of the source positioning accuracy of the LECS and MECS instruments on-board BeppoSAX. From the analysis of a sample of archival images we find that a systematic error, which depends on the spacecraft roll angle and has…

Astrophysics · Physics 2009-11-07 M. Perri , M. Capalbi

We present a new detection algorithm based on the wavelet transform for the analysis of high energy astronomical images. The wavelet transform, due to its multi-scale structure, is suited for the optimal detection of point-like as well as…

We present a theoretical analysis of the measuring algorithm we use when applying the Diffracto-Astrometry technique to Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) saturated stellar images. Theoretical Point Spread…

Instrumentation and Methods for Astrophysics · Physics 2015-05-30 A. Ruelas-Mayorga , L. J. Sanchez , J. Olivares , C. Allen , A. Poveda , R. Costero , A. Nigoche-Netro

Radio tomographic imaging (RTI) enables device free localisation of people and objects in many challenging environments and situations. Its basic principle is to detect the changes in the statistics of some radio quality measurements in…

Other Computer Science · Computer Science 2014-02-13 Bo Wei , Ambuj Varshney , Wen Hu , Neal Patwari , Thiemo Voigt , Chun Tung Chou

We present a novel solution to the camera pose estimation problem, where rotation and translation of a camera between two views are estimated from matched feature points in the images. The camera pose estimation problem is traditionally…

Computer Vision and Pattern Recognition · Computer Science 2018-07-31 Kaveh Fathian , J. Pablo Ramirez-Paredes , Emily A. Doucette , J. Willard Curtis , Nicholas R. Gans

Due to uncertainty on target's motion, the range cell migration (RCM) and azimuth phase error (APE) of moving targets can't be completely compensated in synthetic aperture radar (SAR) processing. Therefore, moving targets often appear…

Information Theory · Computer Science 2015-07-09 Xinhua Mao

The ROSAT All-Sky Survey (RASS) represents one of the most complete and sensitive soft X-ray all-sky surveys to date. However, the deficient positional accuracy of the RASS Bright Source Catalog (BSC) and subsequent lack of firm optical…

High Energy Astrophysical Phenomena · Physics 2016-12-14 Shuang Gao , Song Wang , Jifeng Liu

This paper describes a linear solution method for near-light photometric stereo by exploiting symmetric light source arrangements. Unlike conventional non-convex optimization approaches, by arranging multiple sets of symmetric nearby light…

Computer Vision and Pattern Recognition · Computer Science 2026-03-18 Lilika Makabe , Heng Guo , Hiroaki Santo , Fumio Okura , Yasuyuki Matsushita

Supervised and unsupervised homography estimation methods depend on image pairs tailored to specific modalities to achieve high accuracy. However, their performance deteriorates substantially when applied to unseen modalities. To address…

Computer Vision and Pattern Recognition · Computer Science 2026-03-05 Jinkun You , Jiaxin Cheng , Jie Zhang , Yicong Zhou
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