Adaptive energy filtering method based on time-domain image sequences for high-accuracy spot target localization

Abstract

High-accuracy spot target localization is an essential optical measurement technique in fields such as astronomy and biophysics. Random noise generated during the imaging process limits further improvement of centroiding accuracy. Research for centroiding methods can no longer meet the demand for higher accuracy. This limitation is even more severe for low signal to noise ratio (SNR) imaging measurements. This paper proposes an energy filtering method based on time-domain extended image sequences, which is a typical application such as a star tracker. The energy variations of the spot in continuous sequences are analyzed, and the energy is filtered at pixel level. The filtered pixel response that is closer to real energy is involved in the calculation of the centroid. Adaptive variations of filter parameters for different energy distributions are also realized. Both simulations and laboratory experiments are designed to verify the effectiveness of the approach. The results show that this method can effectively and adaptively filter the spot energy at pixel level and further improve centroiding accuracy.