Deconvolution of background-subtracted shift-and-add image by a modeled point-spread-function |
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Authors: | Susumu Kuwamura Fumiaki Tsumuraya Makoto Sakamoto Noriaki Miura Naoshi Baba |
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Institution: | (1) Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA |
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Abstract: | Shift-and-add (SAA) is a simple method for celestial speckle imaging. However, the raw SAA-image, a direct output of the SAA
operations, is not useful, because a seeing-dependent huge background is superimposed on the high-resolution image of the
object. To obtain the latter, a background subtraction (BGS) is applied on the raw SAA-image. The BGS-image so obtained includes
negativities due to an over-subtraction that causes brightnesses of the object’s image biased downward. The negativity in
the BGS-image can be removed by a deconvolution with a point-spread-function (PSF) that has negative values. In this paper,
we model the PSF with a shape that possesses peak and concave portions, and perform a deconvolution by iteratively estimating
the object’s image and the model parameters. The simulated experiment has shown that the present algorithm can restore the
object’s image with unbiased brightnesses. Processing the observed speckle data of Io (a Jupiter satellite) by the present
method has yielded a feasible Io image with reduced negativities. |
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Keywords: | |
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