scholarly journals HST Image Restoration: Current Capabilities and Future Prospects

1994 ◽  
Vol 158 ◽  
pp. 61-69 ◽  
Author(s):  
Robert J. Hanisch ◽  
Richard L. White
Keyword(s):  
Image Restoration ◽  
Dynamic Range ◽  
Hubble Space Telescope ◽  
Spherical Aberration ◽  
Wide Field ◽  
Secondary Mirror ◽  
Faint Object ◽  
Spread Function ◽  
Restoration Algorithms ◽  
Space Variant

The spherical aberration in the primary mirror of the Hubble Space Telescope causes more than 80% of the light from a point source to be spread into a halo of radius of 2–3 arcsec. The point spread function (PSF) is both time variant (resulting from spacecraft jitter and desorption of the secondary mirror support structure) and space variant (owing to the Cassegrain repeater optics in the Wide Field / Planetary Camera). A variety of image restoration algorithms have been utilized on HST data with some success, although optimal restorations require better modeling of the PSF and the development of efficient restoration algorithms that accommodate a spacevariant PSF. The first HST servicing mission (December 1993) will deploy a corrective optics system for the Faint Object Camera and the two spectrographs and a second generation WF/PC with internal corrective optics. As simulations demonstrate, however, the restoration algorithms developed now for aberrated images will be very useful for removing the remaining diffraction features and optimizing dynamic range in post-servicing mission data.

scholarly journals A 21 Centimeter Absorber Identified with a Spiral Galaxy: Hubble Space Telescope Faint Object Spectrograph and Wide-Field Camera Observations of 3CR 196

1996 ◽  
Vol 456 ◽  
pp. 132 ◽  
Author(s):  
Ross D. Cohen ◽  
E. A. Beaver ◽  
Athanassios Diplas ◽  
Vesa T. Junkkarinen ◽  
Thomas A. Barlow ◽  
...  
Keyword(s):  
Spiral Galaxy ◽  
Hubble Space Telescope ◽  
Wide Field ◽  
Space Telescope ◽  
Faint Object ◽  
Faint Object Spectrograph

On the Use of Electrostrictive Actuators in Recovering the Optical Performance of the Hubble Space Telescope

1994 ◽  
Vol 360 ◽  
Author(s):  
James L. Fanson
Keyword(s):  
Hubble Space Telescope ◽  
Spherical Aberration ◽  
Wide Field ◽  
Optical Performance ◽  
Space Telescope ◽  
Jet Propulsion ◽  
Primary Mirror ◽  
Optical Correction ◽  
Active Mirror ◽  
Multilayer Actuators

AbstractThis paper describes the development of a space qualified active mirror—the Articulating Fold Mirror—which forms part of the scheme for recovering the optical performance of the Hubble Space Telescope. Three Articulating Fold Mirrors are incorporated into the optical train of the Jet Propulsion Laboratory's Wide Field and Planetary Camera-2, which was installed into Hubble by astronauts in December, 1993. Each Articulating Fold Mirror utilizes six electrostrictive ceramic multilayer actuators to precisely position a mirror in tip and tilt in order to correct the spherical aberration of the Hubble Space Telescope's primary mirror. Flight qualification aspects of the electrostrictive actuators are described. Pre- and postrepair images from the Wide Field and Planetary Camera, showing the effect of the optical correction, are presented.

scholarly journals THE HUBBLE SPACE TELESCOPE WIDE FIELD CAMERA 3 EARLY RELEASE SCIENCE DATA: PANCHROMATIC FAINT OBJECT COUNTS FOR 0.2-2 μm WAVELENGTH

2011 ◽  
Vol 193 (2) ◽  
pp. 27 ◽  
Author(s):  
Rogier A. Windhorst ◽  
Seth H. Cohen ◽  
Nimish P. Hathi ◽  
Patrick J. McCarthy ◽  
Russell E. Ryan ◽  
...  
Keyword(s):  
Hubble Space Telescope ◽  
Wide Field ◽  
Science Data ◽  
Space Telescope ◽  
Early Release ◽  
Faint Object

scholarly journals Searching for Low–Mass Companions with the HST WF/PC

1992 ◽  
Vol 135 ◽  
pp. 365-368
Author(s):  
William A. Baum
Keyword(s):  
Hubble Space Telescope ◽  
Spherical Aberration ◽  
Wide Field ◽  
Space Telescope ◽  
Optical Correction ◽  
Nearby Stars ◽  
Low Mass ◽  
Search Capability

AbstractOwing to the spherical aberration of the Hubble Space Telescope, prospects are now poor for the astrometric detection of low–mass companions of nearby stars with the Wide–Field / Planetary Camera. The installation of a new camera (WF/PC-II) incorporating an optical correction for the telescope will only partially recover the low–mass companion search capability.

scholarly journals Deep learning for studies of galaxy morphology

2016 ◽  
Vol 12 (S325) ◽  
pp. 191-196 ◽  
Author(s):  
D. Tuccillo ◽  
M. Huertas-Company ◽  
E. Decencière ◽  
S. Velasco-Forero
Keyword(s):  
Deep Learning ◽  
Hubble Space Telescope ◽  
Wide Field ◽  
Human Intervention ◽  
Convolutional Networks ◽  
Point Spread ◽  
Profile Fitting ◽  
Spread Function ◽  
High Level ◽  
Infrared Survey

AbstractEstablishing accurate morphological measurements of galaxies in a reasonable amount of time for future big-data surveys such as EUCLID, the Large Synoptic Survey Telescope or the Wide Field Infrared Survey Telescope is a challenge. Because of its high level of abstraction with little human intervention, deep learning appears to be a promising approach. Deep learning is a rapidly growing discipline that models high-level patterns in data as complex multilayered networks. In this work we test the ability of deep convolutional networks to provide parametric properties of Hubble Space Telescope like galaxies (half-light radii, Sérsic indices, total flux etc..). We simulate a set of galaxies including point spread function and realistic noise from the CANDELS survey and try to recover the main galaxy parameters using deep-learning. We compare the results with the ones obtained with the commonly used profile fitting based software GALFIT. This way showing that with our method we obtain results at least equally good as the ones obtained with GALFIT but, once trained, with a factor 5 hundred time faster.

scholarly journals Advanced Processing of Images Obtained from Wide-field Astronomical Optical Systems

10.14311/1334 ◽  
2011 ◽  
Vol 51 (1) ◽  
Author(s):  
M. Řeřábek ◽  
P. Páta
Keyword(s):  
Image Data ◽  
Optical Systems ◽  
General View ◽  
Wide Field ◽  
Optical Aberrations ◽  
Transfer Characteristics ◽  
Astronomical Image ◽  
Wide Range ◽  
Spread Function ◽  
Space Variant

The principal aim of this paper is to present a general view of the special optical systems used for acquiring astronomical image data, commonly referred to as WFC or UWFC (Ultra Wide Field Camera), and of their transfer characteristics. UWFC image data analysis is very difficult in general, not only because the systems have so-called space variant (SV) properties. Images obtained from UWFC systems are usually incorrectly presented due to a wide range of optical aberrations and distortions. The influence of the optical aberrations increases towards the margins of the field of view. These aberrations distort the point spread function of the optical system and rapidly cut the accuracy of the measurements. This paper deals with simulation and modelling of the UWFC optical systems used in astronomy and their transfer characteristics.

scholarly journals A modified algorithm for Cleaning wide-field maps with extended structures

1991 ◽  
Vol 131 ◽  
pp. 242-242
Author(s):  
K. S. Dwarakanath ◽  
A. A. Deshpande ◽  
N. Udaya Shankar
Keyword(s):  
Point Spread Function ◽  
Dynamic Range ◽  
Computing Time ◽  
Point Sources ◽  
Aperture Synthesis ◽  
Wide Field ◽  
Point Spread ◽  
Sky Survey ◽  
Spread Function ◽  
Modified Algorithm

AbstractA simple but effective modification to the conventional CLEAN algorithm is suggested. This modification ensures both stability and speed when CLEAN is applied to maps containing a mixture of point sources and extended structures. The method has been successfully applied to the recently-completed sky survey at 34.5 MHz. This survey was made using the Gauribidanur T array (GEETEE) in 1-D aperture synthesis mode. Since in this case the ‘dirty beam’ (point spread function) cannot be directly computed, a method to obtain this is discussed in detail. The results of this deconvolution procedure have been encouraging in terms of reduced computing time and improved dynamic range in our maps. This algorithm should find wider application in deconvolving maps which have both extended structures and point sources.

scholarly journals Prospects for space Telescope in the search for other Planetary Systems

1985 ◽  
Vol 112 ◽  
pp. 75-84
Author(s):  
J. L. Russell
Keyword(s):  
High Speed ◽  
Hubble Space Telescope ◽  
Planetary Systems ◽  
Wide Field ◽  
Minor Planets ◽  
Scientific Instruments ◽  
The Moon ◽  
Space Telescope ◽  
Faint Object

The Hubble Space Telescope (ST) will be launched with five dedicated scientific instruments and a capability to do astrometric measurements with the fine guidance sensors. Four of these – the Faint Object Camera, the Wide Field Camera, the Fine Guidance Sensors and the High Speed Photometer – can be used in the search for extrasolar planetary systems. The Faint Object Camera will be able to directly detect planets around a few of the nearby bright stars. The Wide Field Camera and the Fine Guidance Sensors can be used astrometrically, both with an accuracy of about 2 mas per observation. The High Speed Photometer possibly can detect planets during occultation of stars by the moon and minor planets. The ST is expected to be launched in mid-1986 and these observations are the among the first planned with the instruments.

Image Pro-Correction for Defocus Blur Image Based on Wiener Filtering

2013 ◽  
Vol 397-400 ◽  
pp. 2257-2261 ◽  
Author(s):  
Qiong Li ◽  
Yong Hang Tai ◽  
Zai Qing Chen ◽  
Qiu Yue Yang ◽  
Bin Zhuo
Keyword(s):  
Dynamic Range ◽  
Circular Disk ◽  
High Dynamic Range ◽  
Wiener Filtering ◽  
Original Image ◽  
Defocus Blur ◽  
Spread Function ◽  
Blurred Image ◽  
High Dynamic ◽  
Restoration Algorithms

Image restoration is an important application of the digital image processing. Unlike traditional restoration algorithms that operate on a blurred image to recover the original, we propose a technique that the correction should be applied to the original image before blurring. To accomplish this, we approximate the Point-Spread-Function (PSF) of different defocus blur images by the circular disk. According to the estimated PSF, the original image is pro-processed based on Wiener filtering and High Dynamic Range (HDR) compression. Experiments results show that using this technique can help ameliorate the visual blur and the defocus images finally have a sharp vision.

Study on Motion Blur Image Restoration Algorithms

2013 ◽  
Vol 753-755 ◽  
pp. 2976-2979
Author(s):  
Yu Fan ◽  
Xue Feng Wu
Keyword(s):  
Mathematical Model ◽  
Image Restoration ◽  
Point Spread Function ◽  
Motion Blur ◽  
Inverse Filtering ◽  
Point Spread ◽  
Spread Function ◽  
Blurred Image ◽  
Restoration Algorithms ◽  
Blurred Images

The restore algorithm of the image blurred by motion is proposed, and a mathematical model based on motion blur system is eomtrueted£®The Point spread function of the motion blur is given£®According to the characteristics of blurred images£¬the parameters of point spread function are estimated ,and three methods are introduced for image restoration. The three methods are inverse filtering of image restoration,Lucy-Richardson image restoration and Wiener image restoration.The principles of the three image restoration methods are analyzed. The motion blurred image restoration experiment is made. The results show that the visibility of the image is improved ,and the image restoration is more stable.

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