A High-contrast Imaging Algorithm: Optimized Image Rotation and Subtraction

Abstract

Image Rotation and Subtraction (IRS) is a high-contrast imaging technique which can be used to suppress the speckles noise and facilitate the direct detection of exoplanets. IRS is different from Angular Differential Imaging (ADI), in which it will subtract a copy of the image with 180 degrees rotated around its PSF center, rather than the subtraction of the median of all of the PSF images. Since the planet itself will be rotated to the other side of the PSF, IRS does not suffer from planet self-subtraction. In this paper, we have introduced an optimization algorithm to IRS (OIRS), which can provide an extra contrast gain at small angular separations. The performance of OIRS has been demonstrated with ADI data. We then made a comparison of the signal to noise ratio (S/N) achieved by algorithms of locally optimized combination of images (LOCI) and OIRS. Finally we found that OIRS algorithm can deliver a better S/N for small angular separations.

18 pages, 8 eps figures, 1 table, accepted for publication in The Astrophysical Journalon on Jan. 10th, 2015

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• Half-sibling regression meets exoplanet imaging: PSF modeling and subtraction using a flexible, domain knowledge-driven, causal framework
• Portable Adaptive Optics for Exoplanet Imaging
• Design and experimental test of an optical vortex coronagraph
• Performance Calibration of the Wavefront Sensor's EMCCD Detector for the Cool Planets Imaging Coronagraph Aboard CSST