Image processing techniques for gas morphology studies in the coma of comet Halley

Schwarz, G.; Cosmovici, C. B.; Mack, Peter; Ip, W.-H.

doi:10.1016/0273-1177(89)90263-9

Cited by 19 publications

(9 citation statements)

References 7 publications

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“…Application of multiple enhancing techniques in succession to a given image is extremely tempting and it has been attempted in the literature (e.g., Schwarz et al 1989, Manzini et al 2012). An example is the application of a technique suited for detecting radial features (such as division by a "background") followed by a technique that searches for "wiggles" or "inflections" in the radial features 3 to identify shell-like structures and such a technique could be as simple as dividing by an "ideal" radial profile (Schwarz et al 1989). While this approach is reasonable, such shell-like structures should also be detectable by other techniques already discussed in this paper (e.g., radially variable spatial filtering, radial shift differencing, temporal derivative).…”

Section: Discussionmentioning

confidence: 99%

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Image enhancement techniques for quantitative investigations of morphological features in cometary comae: A comparative study

Samarasinha

Larson

2014

Icarus

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Many cometary coma features are only a few percent above the ambient coma (i.e., the background) and therefore coma enhancement techniques are needed to discern the morphological structures present in cometary comae. A range of image enhancement techniques widely used by cometary scientists is discussed by categorizing them and carrying out a comparative analysis. The enhancement techniques and the corresponding characteristics are described in detail and the respective mathematical representations are provided. As the comparative analyses presented in this paper make use of simulated images with known coma features, the feature identifications as well as the artifacts caused by enhancement provide an objective and definitive assessment of the various techniques. Examples are provided which highlight contrasting capabilities of different techniques to pick out qualitatively distinct features of widely different strengths and spatial scales. On account of this as well as serious image artifacts and spurious features associated with certain enhancement techniques, confirmation of the presence of coma features using qualitatively different techniques is strongly recommended.

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Section: Discussionmentioning

confidence: 99%

“…Azimuthal renormalization and variations of it are referred to as "ring masking" by some authors in the early literature (e.g.,Schwarz et al 1989). …”

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confidence: 99%

Image enhancement techniques for quantitative investigations of morphological features in cometary comae: A comparative study

Samarasinha

Larson

2014

Icarus

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“…Although the features themselves are not visible, for a trained eye the distorted coma indicates their presence. For reference, exhaustive comparisons of image enhancing techniques for dust coma morphology can be found in Schwarz et al (1989), Larson & Slaughter (1992), Schleicher & Farnham (2004), Vincent (2010) and, Samarasinha & Larson (2011).…”

Section: Image Enhancement and Detection Of Featuresmentioning

confidence: 99%

Spin and activity of comet 67P/Churyumov-Gerasimenko

Vincent

Lara

Tozzi

et al. 2013

A&A

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Aims. In 2014 ESA's spacecraft Rosetta will reach its final target: comet 67P/Churyumov-Gerasimenko (67P). Although this comet has been studied in great detail over the past decade, there are still some uncertainties regarding the actual spin orientation and the distribution of active regions on the surface. We here give an overview of our current knowledge of these critical parameters based mainly on data acquired during the last orbit of the comet aims to deliver a review of what is our current knowledge of these critical parameters. Methods. We based our analysis on the modeling and interpretation of dust jets seen in the coma of 67P during the 2009 apparition.Results. The inversion of ground-based images leads to an estimate of the spin axis orientation (RA = 40• ± 10 • , Dec = 70 • ± 10 • ) and to the localization of the most prominent active areas on the surface of the nucleus. We can reproduce the activity with three active regions localized at −45• , 0• , and +60• of latitude. We use these results to revisit the observations taken during the 2003 apparition and examine the changes in activity between then and now. Our model from 2009 is also valid for the 2003 data, which suggests that no significant change in spin orientation and active areas occurred from one perihelion passage to the next. Finally, we combine all the results to propose some predictions on the activity to be expected in 2015 during the comet exploration phase of the Rosetta mission.

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“…Observations, Data Reduction, and Image Processing As was mentioned above, the observations were obtained by R.E. There are several review articles dealing with the image processing techniques applied in cometary imaging (Matuska et al, 1978;Klinglesmith, 1981;Larson, 1986;A'Hearn et al, 1986;Schwarz et al, 1989;Larson and Slaughter, 1992) and in our tests we tried several of them to get more information about the structures in the inner part of fan-shaped coma. This configuration provided a scale of 0.73 arcset/pixel, and for the whole chip of the 320 x 512 pixel image the field of view reached of the 3.9 x 6.2 arcmin in size.…”

Section: Introductionmentioning

confidence: 99%

Near-nucleus imaging of comet IRAS-Araki-Alcock 1983H1

Kubacek

Pittichová

1996

Earth Moon Planet

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Several digital image processing techniques were used to improve the visibility of details, fans and jets, in the inner coma of the comet IRAS-Araki-Alcock 1983VII on the short CCD-exposures taken by R. E. Schild with the 61-cm telescope through three I, J, and F band filters, at the Whipple Observatory during the close approach from May 6 through May 12, 1983. About 140 CCD images with the pixel size of 0.73 give a resolution about 20 km, and selected CDD frames presented together with isophotes demonstrate the variation and interrelation of the coma morphology and the nucleus activities during the observing period. Results and processed images are compared with observations taken by other observers during the same period.

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Image processing techniques for gas morphology studies in the coma of comet Halley

Cited by 19 publications

References 7 publications

Image enhancement techniques for quantitative investigations of morphological features in cometary comae: A comparative study

Image enhancement techniques for quantitative investigations of morphological features in cometary comae: A comparative study

Spin and activity of comet 67P/Churyumov-Gerasimenko

Near-nucleus imaging of comet IRAS-Araki-Alcock 1983H1

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