Avoiding the Geometric Boundary Effect in Shear Measurement

Abstract In image processing, source detections are inevitably affected by the presence of the geometric boundaries in the images, including the physical boundaries of the CCD, and the boundaries of masked regions due to column defects, bright diffraction spikes, etc. These boundary conditions make...

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Bibliographic Details
Published inThe Astrophysical journal Vol. 911; no. 1; p. 10
Main Authors Wang, Haoran, Zhang, Jun, Li, Hekun, Shen, Zhi
Format Journal Article
LanguageEnglish
Published Philadelphia IOP Publishing 01.04.2021
Subjects
Astrophysics
Bias
Boundaries
Boundary conditions
Image processing
Shear
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Summary:Abstract In image processing, source detections are inevitably affected by the presence of the geometric boundaries in the images, including the physical boundaries of the CCD, and the boundaries of masked regions due to column defects, bright diffraction spikes, etc. These boundary conditions make the source detection process not statistically isotropic and can lead to additive shear bias near the boundaries. We build a phenomenological model to understand the bias, and propose a simple method to effectively eliminate the influence of geometric boundaries on shear measurement. We demonstrate the accuracy and efficiency of this method using both simulations and the z -band imaging data from the third data release of the DECam Legacy Survey.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/abe856