New method of star image high precision extraction based on local entropy

A new method of star image high precision extraction has been introduced. The new method is basis of the variety of local entropy of the star sensor image, gained the objective region of star imaging, and then using the centroid method, getting the subpixel position of navigation star. The fast calculate method of the local entropy was provided. The local entropy method has the function of filter to random noise and can eliminate the background grey wavy phenomena, therefore, the method is fit for a point objective image extract, which includes the random and system noise. The simulation experimental result indicates that the star locating precision less than 1/20 using the method in random noise less than 5%.