&lt;title&gt;Multiframe blind deconvolution of infinite-extent objects&lt;/title&gt;

Kampen, William C. van; Paxman, Richard G.

doi:10.1117/12.330227

Cited by 7 publications

(3 citation statements)

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“…The variances are shown together with the Kolmogorov statistics for r 0 = 20 cm. This r 0 value is not measured, just shown for comparison, chosen because the level of the first uncorrected modes (16)(17)(18)(19)(20)(21)(22)(23)(24)) are at about the same level (for WFS FOV). It is not clear how to interpret the variances of the highest modes, 28-36, that don't follow the expected statistics at all.…”

Section: Processing and Resultsmentioning

confidence: 99%

Diverse phase speckle inversion applied to data from the Swedish 1-meter solar telescope

Löfdahl¹,

Scharmer²

2003

SPIE Proceedings

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We report on the use of a new joint phase diverse speckle code, an implementation of a method where a single object and individual phases are estimated from several pairs of phase diverse data. The code was used on 430.5 nm G-band data collected with the newly installed Swedish 1-meter solar telescope in La Palma, equipped with a low-order adaptive optics system. We describe the algorithm briefly, show wavefront statistics and object estimates from the processing and discuss the results. We demonstrate a resolution of 0.12 arc seconds for a time sequence and a large field of view, which is a break-through for ground based solar telescopes.

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Section: Processing and Resultsmentioning

confidence: 99%

Diverse phase speckle inversion applied to data from the Swedish 1-meter solar telescope

Löfdahl¹,

Scharmer²

2003

SPIE Proceedings

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“…The reader is referred to Löfdahl et al ( 2007 ) for an in-depth discussion of post-facto reconstruction techniques used in solar astronomy. In addition, individual methods are discussed by: speckle interferometry (Wöger et al , 2008 ; Wöger and von der Lühe, 2008 ), phase-diversity and phase-diverse speckle (Löfdahl and Scharmer, 1994 ; Seldin and Paxman, 1994 ; Paxman et al , 1996 ; Seldin et al , 1999 ; Löfdahl et al , 2007 ; Valenzuela et al , 2010 ), multi-frame-blind-deconvolution (MFBD) (van Kampen and Paxman, 1998 ; Löfdahl, 2007 ; Scharmer et al , 2010 ), and Multi-Object-Multi-Frame-Blind Deconvolution (MOMFBD) (van Noort et al , 2005 ).…”

Section: The Case For Post-facto Processingmentioning

confidence: 99%

Solar Adaptive Optics

Rimmelé

Mariño

2011

Living Rev. Solar Phys.

108

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Adaptive optics (AO) has become an indispensable tool at ground-based solar telescopes. AO enables the ground-based observer to overcome the adverse effects of atmospheric seeing and obtain diffraction limited observations. Over the last decade adaptive optics systems have been deployed at major ground-based solar telescopes and revitalized ground-based solar astronomy. The relatively small aperture of solar telescopes and the bright source make solar AO possible for visible wavelengths where the majority of solar observations are still performed. Solar AO systems enable diffraction limited observations of the Sun for a significant fraction of the available observing time at ground-based solar telescopes, which often have a larger aperture than equivalent space based observatories, such as HINODE. New ground breaking scientific results have been achieved with solar adaptive optics and this trend continues. New large aperture telescopes are currently being deployed or are under construction. With the aid of solar AO these telescopes will obtain observations of the highly structured and dynamic solar atmosphere with unprecedented resolution. This paper reviews solar adaptive optics techniques and summarizes the recent progress in the field of solar adaptive optics. An outlook to future solar AO developments, including a discussion of Multi-Conjugate AO (MCAO) and Ground-Layer AO (GLAO) will be given.Electronic Supplementary MaterialSupplementary material is available for this article at 10.12942/lrsp-2011-2.

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“…Compared with the speckle reconstruction, a significantly smaller number of images, about 5−20, is sufficient (see, e.g., Löfdahl et al 2007). Such a multi-frame blind deconvolution (MFBD, Schulz 1993;van Kampen & Paxman 1998;Löfdahl 2002) can be applied to series of images of a single real object. The approach was extended by Löfdahl (2002) and van Noort et al (2005) to cover also the case of multiple objects, e.g., simultaneous images of the same object in slightly different wavelengths or different polarization states.…”

Section: Introductionmentioning

confidence: 99%

Application of speckle and (multi-object) multi-frame blind deconvolution techniques on imaging and imaging spectropolarimetric data

Puschmann¹,

Beck²

2011

A&A

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Context. Ground-based imaging and imaging spectropolarimetric data are often subjected to post-facto reconstruction techniques to improve the spatial resolution. Aims. We test the effects of reconstruction techniques on two-dimensional data to determine the best approach to improve our data. Methods. We obtained an 1-h time-series of spectropolarimetric data in the Fe i line at 630.25 nm with the Göttingen Fabry-Pérot Interferometer (FPI) that are accompanied by imaging data in the blue continuum at 431.3 nm and Ca ii H at 396.85 nm. We apply both speckle and (multi-object) multi-frame blind deconvolution ((MO)MFBD) techniques. We use the "Göttingen" speckle and speckle deconvolution codes and the MOMFBD code in the implementation of Van Noort et al. (2005). We compare the resulting spatial resolution and investigate the impact of the image reconstruction on spectral characteristics of the Göttingen FPI data. Results. The speckle reconstruction and MFBD perform similar for our imaging data with nearly identical intensity contrasts. MFBD provides a better and more homogeneous spatial resolution at the shortest wavelength when applied to a series of image bursts. The MOMFBD and speckle deconvolution of the intensity spectra lead to similar results, but our choice of settings for the MOMFBD yields an intensity contrast smaller by about 2% at a comparable spatial resolution. None of the reconstruction techniques introduces significant artifacts in the intensity spectra. The speckle deconvolution (MOMFBD) has a rms noise in Stokes V/I of 0.32% (0.20%). The deconvolved spectra thus require a high significance threshold of about 1.0% to separate noise peaks from true signal. A comparison to spectra with a significantly higher signal-to-noise (S/N) ratio and to spectra from a magneto-hydrodynamical simulation reveals that the Göttingen FPI can only detect about 30% of the polarization signal present in quiet Sun areas. The distribution of NCP values for the speckle-deconvolved data matches that of observations with higher S/N better than MOMFBD, but shows seemingly artificially sharp boundaries and unexpected changes of the sign. Conclusions. For our imaging data, both MFBD and speckle reconstruction are equivalent, with a slightly better and more stable performance of MFBD. For the spectropolarimetric data, the higher intensity contrast of the speckle deconvolution is balanced by the smaller amplification of the noise level in the MOMFBD at a comparable spatial resolution. The noise level prevents the detection of weak and diffuse magnetic fields. Future efforts should be directed to improve the S/N of the Göttingen FPI spectra for spectropolarimetric observations to lower the final significance thresholds.

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<title>Multiframe blind deconvolution of infinite-extent objects</title>

Cited by 7 publications

References 8 publications

Diverse phase speckle inversion applied to data from the Swedish 1-meter solar telescope

Diverse phase speckle inversion applied to data from the Swedish 1-meter solar telescope

Solar Adaptive Optics

Application of speckle and (multi-object) multi-frame blind deconvolution techniques on imaging and imaging spectropolarimetric data

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