Design And Implementation Of A Stellar Auto-Searching Algorithm In The CCD Image

In photographic astrometry, Stellar-searching and centering are an important work. Based on a CCD image, an algorithm of automatic stellar searching is designed and implemented in the thesis. Removal of noise is mainly concerned in this algorithm. In detail, we analyze the noises of an astronomic CCD image and design a corresponding algorithm to remove them.Usually, the marginal distribution of a stellar image is a Gaussian, which is used to design the stellar searching algorithm. Because the background of sky is asymmetric and some valid information will be lost after noise processing, some limits must be set to improve the function of the algorithm. A method called a 2D modified moment is chosen to calculate the center of a stellar image. With the initial center and background from the stellar searching, an accurate center and photometry of a star can be calculated.The implementation of the design with VC++6.0 is further described in the thesis. Many CCD image are used to test the mentioned-above algorithm. The results after compared with manual operations show the feasibility and effectiveness of the algorithm.