Detection of sunspot edges in Shack–Hartmann sensor images using the Canny method

Subject of study. Optical distortions formed in the telescope aperture plane owing to atmospheric turbulence along the line of sight are investigated. Aim of study. The aim of this study is to develop a method for determining the contours and edge shift magnitudes of sunspots based on an array of images recorded using a Shack–Hartmann sensor. In addition, solar image displacements in the plane conjugate with the telescope aperture are estimated. Method. The Canny edge detection method is employed to determine the contours and displacement magnitudes of sunspot edges from image arrays obtained using a Shack–Hartmann sensor. The Fried parameter for the Large Solar Vacuum Telescope (LSVT) is estimated on the basis of the variance of differential sunspot shifts calculated using the Canny edge detection algorithm. Main results. Computer vision methods and algorithms are used to process subimages obtained with the Shack–Hartmann sensor. The proposed algorithms for edge detection and Fried parameter estimation are adapted and implemented for the LSVT. Practical significance. The computer vision methods adopted in this study can be used in adaptive optics systems and in the further development of methods for measuring atmospheric optical turbulence profiles.