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X-ray observations with the ROSAT High Resolution Imager (HRI) often have spatial smearing on the order of 10 arcsec (Morse 1994). This degradation of the intrinsic resolution of the instrument (5 arcsec) can be attributed to errors in the…

Astrophysics · Physics 2009-10-31 D. E. Harris , J. D. Silverman , G. Hasinger , I. Lehmann

We introduce new methods for robust high-precision photometry from well-sampled images of a non-crowded field with a strongly varying point-spread function. For this work, we used archival imaging data of the open cluster M37 taken by MMT…

Instrumentation and Methods for Astrophysics · Physics 2015-06-24 S. -W. Chang , Y. -I. Byun , J. D. Hartman

Optical positions from the SuperCOSMOS Sky Survey have been compared in detail with accurate radio positions that define the second realisation of the International Celestial Reference Frame (ICRF2). The comparison was limited to the IIIaJ…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Adam Schaefer , Richard Hunstead , Helen Johnston

Compact and low-cost devices are needed for autonomous driving to image and measure distances to objects 360-degree around. We have been developing an omnidirectional stereo camera exploiting two hyperbolic mirrors and a single set of a…

Image and Video Processing · Electrical Eng. & Systems 2021-08-19 Ryota Kawamata , Keiichi Betsui , Kazuyoshi Yamazaki , Rei Sakakibara , Takeshi Shimano

A rotational modulator (RM) gamma-ray imager is capable of obtaining significantly better angular resolution than the fundamental geometric resolution defined by the ratio of detector diameter to mask-detector separation. An RM imager…

Instrumentation and Methods for Astrophysics · Physics 2010-10-15 B. Budden , G. L. Case , M. L. Cherry

The image reconstruction problem of the tomographic imaging technique magnetic particle imaging (MPI) requires the solution of a linear inverse problem. One prerequisite for this task is that the imaging operator that describes the mapping…

Computational Physics · Physics 2019-07-12 Tobias Kluth , Patryk Szwargulski , Tobias Knopp

This paper focuses on the optimal design of a modulated retroreflector (MRR) laser link to establish a high-speed downlink for cube satellites (CubeSats), taking into account the weight and power limitations commonly encountered by these…

Signal Processing · Electrical Eng. & Systems 2024-01-19 Mohammad Taghi Dabiri , Mazen Hasna , Saud Althunibat , Khalid Qaraqe

Estimating homography from a single image remains a challenging yet practically valuable task, particularly in domains like retail, where only one viewpoint is typically available for shelf monitoring and product alignment. In this paper,…

Computer Vision and Pattern Recognition · Computer Science 2025-11-26 Onur Berk Tore , Ibrahim Samil Yalciner , Server Calap

Wide field planetary camera 2 (WFPC2) exposures are already some 20 years older than Gaia epoch observations, or future JWST observations. As such, they offer an unprecedented time baseline for high-precision proper-motion studies, provided…

Instrumentation and Methods for Astrophysics · Physics 2021-05-07 Dana I. Casetti-Dinescu , Terrence M. Girard , Vera Kozhurina-Platais , Imants Platais , Jay Anderson , Elliott P. Horch

This paper is the second in a series describing the Sydney University Molonglo Sky Survey (SUMSS) being carried out at 843MHz with the Molonglo Observatory Synthesis Telescope (MOST). The survey will consist of ~590 4.3deg. x 4.3deg. mosaic…

Examining the extent to which measurements of rotation matrices are close to each other is challenging due measurement noise. To overcome this, data is typically smoothed and Riemannian and Euclidean metrics are applied. However, if…

Numerical Analysis · Mathematics 2025-02-19 P. D. Ledger , W. R. B. Lionheart , J. Elgy

We describe the astrometric reduction of images obtained with the FORS2/VLT camera in the framework of an astrometric planet search around 20 M/L-transition dwarfs. We present the correction of systematic errors, the achieved astrometric…

Solar and Stellar Astrophysics · Physics 2014-05-08 P. F. Lazorenko , J. Sahlmann , D. Segransan , E. L. Martin , M. Mayor , D. Queloz , S. Udry

We developed a source detection algorithm based on the Minimal Spanning Tree (MST), that is a graph-theoretical method useful for finding clusters in a given set of points. This algorithm is applied to gamma-ray bidimensional images where…

Astrophysics · Physics 2008-11-26 Riccardo Campana , Enrico Massaro , Dario Gasparrini , Sara Cutini , Andrea Tramacere

A new physically based method to estimate hemispheric-directional reflectance factor (HDRF) from lightweight multispectral cameras that have a downwelling irradiance sensor is presented. It combines radiometry with photogrammetric computer…

Data Analysis, Statistics and Probability · Physics 2019-05-10 Klaus Schneider-Zapp , Manuel Cubero-Castan , Dai Shi , Christoph Strecha

The Hard X-ray Modulation Telescope (HXMT) will perform an all-sky survey in hard X-ray band as well as deep imaging of a series of small sky regions. We expect various compact objects to be detected in these imaging observations. Point…

Instrumentation and Methods for Astrophysics · Physics 2015-11-11 Zhuoxi Huo , Yiming Li , Xiaobo Li , Jianfeng Zhou

We improved a previously proposed method of using closed-orbit modulation for linear optics correction. Instead of fitting individual closed orbits, the improved method decomposes the orbit oscillation data into two orthogonal modes and…

Accelerator Physics · Physics 2023-06-14 Xiaobiao Huang , Xi Yang

Radar and lidar, provided by two different range sensors, each has pros and cons of various perception tasks on mobile robots or autonomous driving. In this paper, a Monte Carlo system is used to localize the robot with a rotating radar…

Robotics · Computer Science 2022-11-29 Huan Yin , Yue Wang , Li Tang , Rong Xiong

Understanding high-resolution (HR) images remains a critical challenge for multimodal large language models (MLLMs). Recent approaches leverage vision-based retrieval-augmented generation (RAG) to retrieve query-relevant crops from HR…

Computer Vision and Pattern Recognition · Computer Science 2026-03-20 Fan Yang , Xingping Dong , Xin Yu , Wenhan Luo , Wei Liu , Kaihao Zhang

In computed tomography (CT), the relative trajectories of a sample, a detector, and a signal source are traditionally considered to be known, since they are caused by the intentional preprogrammed movement of the instrument parts. However,…

Computer Vision and Pattern Recognition · Computer Science 2021-11-11 Mark Griguletskii , Mikhail Chekanov , Oleg Shipitko

We present a novel automatic adaptive aperture photometry algorithm for measuring the total magnitudes of merging galaxies with irregular shapes. First, we use a morphological pattern recognition routine for identifying the shape of an…

Instrumentation and Methods for Astrophysics · Physics 2017-02-08 Jen-Chao Huang , Chorng-Yuan Hwang