Robust focusing by Orientation Code Matching

This paper has proposed a novel and robust scheme of image focusing by introducing a new measure of focusing based on orientation code matching. (hereinafter, OCM) A unique pencil-shape profile has been found through comparing the similarity between any patterns extracted at the same position within their own scenes. Based on this profile, a new evaluation function, named complemental pencil volume, (hereinafter, CPV), is defined and calculated to represent local sharpness of images, either in or out of focus. Then through a designed local-scope searching algorithm, the maximum of CPV, which corresponds to the just focused image, is searching in this schema. The proposed method of focusing can be applied to cases of ill-condition with low contrast observations. Experiment results show that the OCM-based focusing is very robust to change of brightness and even more irregularities in the real imaging system, like dark condition and so on.