A new focus measure method using moments

In this paper, we propose a new simple yet effective focus measure method. By this method, focus information can be deduced from the 2nd- or 4th-order central moments of a sequence of images. The advantage of the moment-based method over existing schemes is that it gives an explicit expression of the parameter of the Point Spread Function (PSF). After appropriate processing, we can get a curve which is independent of imaged objects and use it to express the blur property of the imaging system. Results obtained from simulation studies and a practical application demonstrate the effectiveness of the proposed method.