Study of Point Spread Function of Astronomical Object Imaging
The research of point spread function (PSF) of astronomical object imaging is very important to the astronomical image restoration. In this paper, the simulated atmospheric turbulent phase screen, the short exposure PSF and long exposure PSF during the as
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Abstract The research of point spread function (PSF) of astronomical object imaging is very important to the astronomical image restoration. In this paper, the simulated atmospheric turbulent phase screen, the short exposure PSF and long exposure PSF during the astronomical object imaging are studied. One novel Gaussian process move-and-superposition model for representing the final astronomical object long exposure PSF formation is proposed. The proposed model obtains more accurate final PSF of astronomical object imaging.* Keywords Point Spread Function · Astronomical object · Imaging
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Introduction
The major astronomical object imaging degradation of a ground-based telescope is caused by random fluctuations of the optical way between the Earth’s atmospheric turbulence and the image formation device itself (telescope imaging system). Research on the point spread function (PSF) of astronomical object imaging includes three parts: firstly, influence of the atmospheric turbulence; secondly, the short exposure PSF gained from the atmospheric turbulence and the telescope system; finally, the long exposure PSF generated by the short exposure PSF. Influence of the turbulence in image formation were analyzed through atmospheric turbulent phase screen [1~3] by a lot of scholar. McGlamery, Welsh and Sedmak use J. Yu() College of Computer and Information Engineering, Hanshan Normal University, Chaozhou 521041, Guangdong, China e-mail: [email protected] Q. Yin · P. Guo Image Processing and Pattern Recognition Laboratory, Beijing Normal University, Beijing 100875, China e-mail: [email protected], [email protected] © Springer Science+Business Media Singapore 2016 K.J. Kim and N. Joukov (eds.), Information Science and Applications (ICISA) 2016, Lecture Notes in Electrical Engineering 376, DOI: 10.1007/978-981-10-0557-2_39
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the Fast Fourier Transformation (FFT) based method [4~6] to simulate atmospheric turbulent phase screen. Their method is convenient and effectively. In ground-based observations, there are obviously distinct assumptions in modeling of astronomical object imaging degradation by the short-exposure PSF (exposure time about milliseconds usually < 15ms) and the long-exposure PSF (exposure time about minutes even hours). After the atmospheric turbulent phase screen is effectively simulated, the short exposure PSF can be easily gained by pupil function of the telescope system. Research on the generation of the long exposure PSF is comparatively rare. Scholars [11~14] just simply add all the short exposure PSF together to generate the long-exposure PSF which called in this paper simple superposition model. These simple superposition models are not accurate enough to represent the long exposure PSF, which is an extended speckle rather than the same size with the short exposure PSF. As a result, the simple superposition model of long exposure PSF will cause imperfect astronomical image restoration. In this paper, a more accurate method to obtain an estimation of the long-exposure PSF by a set o
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