Wide-field, Non-mechanical Beam Steering with Space-Variant Wavefront Correction

2014 ◽  
Author(s):  
Abbie T. Watnik ◽  
James R. Lindle ◽  
Vincent A. Cassella
Keyword(s):  
Beam Steering ◽  
Wide Field ◽  
Wavefront Correction ◽  
Space Variant

scholarly journals Space Variant PSF – Deconvolution of Wide-Field Astronomical Images

10.14311/1023 ◽  
2008 ◽  
Vol 48 (3) ◽  
Author(s):  
M. Řeřábek
Keyword(s):  
Optical System ◽  
Imaging System ◽  
Real Data ◽  
Wavefront Aberration ◽  
Wide Field ◽  
Optical Aberrations ◽  
Optical Aberration ◽  
Transfer Characteristics ◽  
Astronomical Images ◽  
Space Variant

The properties of UWFC (Ultra Wide-Field Camera) astronomical systems along with specific visual data in astronomical images contribute to a comprehensive evaluation of the acquired image data. These systems contain many different kinds of optical aberrations which have a negatively effect on image quality and imaging system transfer characteristics, and reduce the precision of astronomical measurement. It is very important to figure two main questions out. At first: In which astrometric depend on optical aberrations? And at second: How optical aberrations affect the transfer characteristics of the whole optical system. If we define the PSF (Point Spread Function) [2] of an optical system, we can use some suitable methods for restoring the original image. Optical aberration models for LSI/LSV (Linear Space Invariant/Variant) [2] systems are presented in this paper. These models are based on Seidel and Zernike approximating polynomials [1]. Optical aberration models serve as suitable tool for estimating and fitting the wavefront aberration of a real optical system. Real data from the BOOTES (Burst Observer and Optical Transient Exploring System) experiment is used for our simulations. Problems related to UWFC imaging systems, especially a restoration method in the presence of space variant PSF are described in this paper. A model of the space variant imaging system and partially of the space variant optical system has been implemented in MATLAB. The “brute force” method has been used for restoration of the testing images. The results of different deconvolution algorithms are demonstrated in this paper. This approach could help to improve the precision of astronomic measurements. 

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 Rapid wide-field imaging through scattering media by digital holographic wavefront correction

2019 ◽  
Vol 58 (11) ◽  
pp. 2845 ◽  
Author(s):  
Runze Li ◽  
Tong Peng ◽  
Meiling Zhou ◽  
Xianghua Yu ◽  
Peng Gao ◽  
...  
Keyword(s):  
Wide Field ◽  
Scattering Media ◽  
Wavefront Correction ◽  
Field Imaging ◽  
Wide Field Imaging

scholarly journals PSF Estimation of Space-Variant Ultra-Wide Field of View Imaging Systems

2017 ◽  
Vol 7 (2) ◽  
pp. 151 ◽  
Author(s):  
Petr Janout ◽  
Petr Páta ◽  
Petr Skala ◽  
Jan Bednář
Keyword(s):  
Field Of View ◽  
Imaging Systems ◽  
Wide Field ◽  
Wide Field Of View ◽  
Space Variant ◽  
Psf Estimation

scholarly journals Wide Field-of-view and Broadband Terahertz Beam Steering Based on Gap Plasmon Geodesic Antennas

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Kaipeng Liu ◽  
Yinghui Guo ◽  
Mingbo Pu ◽  
Xiaoliang Ma ◽  
Xiong Li ◽  
...  
Keyword(s):  
Beam Steering ◽  
Field Of View ◽  
Wide Field ◽  
Wide Field Of View ◽  
Broadband Terahertz

Extremum seeking control for simultaneous beam steering and wavefront correction

2006 ◽  
Author(s):  
C. Danielson ◽  
S. Lacy ◽  
B. Hindman ◽  
P. Collier ◽  
J. Hunt ◽  
...  
Keyword(s):  
Beam Steering ◽  
Extremum Seeking ◽  
Wavefront Correction ◽  
Extremum Seeking Control

Laboratory quantification of a plenoptic wavefront sensor with extended objects

2020 ◽  
Vol 497 (4) ◽  
pp. 4580-4586
Author(s):  
Zhentao Zhang ◽  
Nazim Bharmal ◽  
Tim Morris ◽  
Yonghui Liang
Keyword(s):  
Adaptive Optics ◽  
Closed Loop ◽  
Optical Design ◽  
Wavefront Sensor ◽  
Wavefront Sensing ◽  
Wide Field ◽  
Loop Correction ◽  
Wavefront Correction ◽  
Set Up ◽  
Experimental Bench

ABSTRACT Adaptive optics (AO) is widely used in ground-based telescopes to compensate the effects of atmosphere distortion, and the wavefront sensor is a significant component in the AO systems. The plenoptic wavefront sensor has been proposed as an alternative wavefront sensor adequate for extended objects and wide field of views. In this paper, a experimental bench has been set up to investigate the slope measurement accuracy and closed-loop wavefront correction performance for extended objects. From the experimental results, it has been confirmed that plenoptic wavefront sensor is suitable for extended objects wavefront sensing with proper optical design. The slope measurements have a good linearity and accuracy when observing extended objects. The image quality is significantly improved after closed-loop correction. A method of global tip/tilt measurement using only plenoptic wavefront sensor frame is proposed in this paper, it is also a potential advantage of plenoptic wavefront sensor in extended objects wavefront sensing.

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.

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