Research And Implementation Of Star Guiding Algorithmy Based On Astronomy Camera And Equatorial

Because of atomosphere and earth rotation,stars seen from earth will keep moving in vision.To guarantee image quality of astronomical observation that usually uses long exposure time,we need stars to keep still in observed image.For this,people develop a guiding method useing astronomy camera and equatorial to track stars in vision.This paper at first introduces some necessary foundations about astronomy,then talks about the whole structure and flow on base of target and principle of star guiding algorithm.After that,we get into,denoising and segmentation for star image,star extraction,star centroiding,star tracking,offset control,every part of star guiding algorithm,and finish implementation of them.In process of implementation,we refer to fundmental algorithms in image processing and principles of automatic control.Star denoising algorithm uses general Wiener filtering method.Star segmentation refers to Otsu algorithm.Star extraction which is based on 4,8 neibor concepts in image processing field and search box can dynamically expand,implements self-adapting function for star searching.Star locating algorithm has time and accuracy in consideration,implements three locating methods,peak locating,centroid locating and locating uses Gaussian curve fiting.Star tracking algorithm uses temporal conherence in star moving and star's features to implement neibor star tracking effect.Offset control algorithm which refers to PID control theory and analysis on star guiding data,make some improvements on the original PI and PD control algorithms,implements algorithms that're more suitable to star guiding context.Besides,to improve extensibility and maintainability of algorithm,we use several methods and patterns to design modules in star guiding algorithm.In testing phase,we use simulators of star image and equatorial to construct a simulation platform,and test the availability of implementaton.At last,we use a set of real hardwares for astronomical observation to complete some star guiding experiments.Our algorithm's good performance on star guiding is confirmed.