Autofocusing region selection for computer vision

Focusing region selection is an important part in autofocusing algorithm, which directly influences the accuracy, unimodality and stability of the sharpness function curve. Two criteria for focusing region selection are presented. Then, a novel region selection method based on edge mask is proposed. The edge mask is obtained by Canny detector, morphological image processing and central region selecting. This edge mask takes into account the pixels which represent the edge information of the main target. Experiments show that the proposed strategy can significantly exclude the influence of background and noises in the image. It has good adaptivity and anti-noise capability, and therefore improves the performance of the autofocusing system.