Affiliations: [a] Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, Jilin 130033, China | [b] University of Chinese Academy of Sciences, Beijing 100049, China
Correspondence:
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Corresponding author: Yang Liu, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, Jilin 130033, China. E-mail: liuy_ciomp@163.com.
Abstract: Application in the actual using, obviously different intensity distribution characteristics are shown in the images of solar magnetic field at extreme ultraviolet (EUV) wavelength. When it comes to displacement measurements by digital image correlation (DIC), it has a great impact on ultimate accuracy. It is an interesting and confusing issue that how to evaluate the quality of different regional solar magnetic field images at EUV wavelengths with a simple but effective parameter. This article presents a new valid part parameter for assessment of the quality of different part solar magnetic field images at EUV wavelengths used in DIC which is called comprehensive consideration of mean subset intensity and gradients (CCMSIG). Three regional images (active region, flare region, and coronal hole) are numerically translated in order to confirm that the validity of the novel concept and DIC method is used to compare the displacement measurement results with the accurate results. This paper also discusses the impact on accuracy of deformation measurements when it comes to the subset size associated with regional image quality and subset displacement functions. The results show that mean bias error and standard deviation (STD) for the sub-pixel displacement measurement are in close proximity to the CCMSIG of the calculated regional images and the high-quality regional images are supposed to be with small CCMSIG which is coincident with the theoretical predictions.
Keywords: Quality evaluation, solar magnetic field images, displacement analysis, extreme ultraviolet
