Susumu KUWAMURA^1*, Yasuyuki AZUMA¹, Noriaki MIURA¹, Fumiaki TSUMURAYA², Makoto SAKAMOTO², and Naoshi BABA³

¹Department of Computer Sciences, Kitami Institute of Technology, Kitami, Hokkaido 090-8507, Japan
²Nishi-Harima Astronomical Observatory, Sayo, Hyogo 679-5313, Japan
³Division of Applied Physics, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan

(Received March 29, 2013; Accepted October 1, 2013)

In astronomical speckle imaging, deconvolving a shift-and-add (SAA) image has an advantage over deconvolving noisy specklegrams, because an SAA image is an integration of many specklegrams and has a relatively enhanced signal-to-noise ratio. In this paper, to reinforce the deconvolution of a single SAA image, we propose a multiframe deconvolution applied to multiple SAA images that are obtained by diversely recombining the same set of specklegrams to have different point spread functions. We have found that such diverse SAA images can be easily produced by permuting specklegrams to be processed by SAA. The results of experiments using simulated and observational data have shown a robustness of our present approach: in the previous approach of deconvolving a single SAA frame, the resulting object estimate is apt to be influenced by the given SAA frame and the estimation sometimes fails, whereas in the present approach, a reliable object image is stably reconstructed regardless of the given SAA frames.

Key words: astronomical speckle imaging, shift-and-add, cross-correlation, blind deconvolution, multiframe

^*E-mail address: kuwamura@cs.kitami-it.ac.jp