Star centroid extraction in a single-line detector array

Abstract

Earth observation satellites can improve the accuracy of image registration by sensing the stars and determining their centroids, as is applied on GOES-16 meteorological satellite of the United States and Himawari 8 of Japan. In this paper, we propose an improved method to accurately extract the subpixel centroids of the stars observed by a single-line detector array with high spatiotemporal resolution. We firstly design a three-way screening method to accurately and quickly detect the position of the star in a long image sequence. Secondly, we estimate the time when the star passes the center of the detector by finding the peak of the energy curve of the observed star images. Then, we fit the trajectory of the star according to the angular velocity in the field of view of the geostationary satellite. Finally, the subpixel centroid of the star in a certain time can be obtained using the fitted trajectory. To verify our method, we simulate the star images of a single-line detector array for geostationary Earth observation with different magnitudes and different sensor parameters. We carried out extensive experiments on the simulated data. Experimental results show that our star centroid extraction method can accurately detect the observed stars and extract their centroids.