Fast and high sensitivity focusing evaluation function

Abstract

According to requirements of focusing accuracy and speed,by the analysis and comparison of the common auto-focusing evaluation function,this paper proposed a new evaluation function based on gray scale difference:using product of adjacent pixels difference in the horizontal and vertical direction as core function.The algorithm maintained a good computing performance,and its curve was more steep so that could speed focusing convergence rate and improve focusing accuracy.By using threshold value to filter noise,night enhance stability of the algorithm.The experiments show that the algorithm not only has good speed,but also has high sensitivity.It's suitable for system with high real-time demanding,such as microscope auto-focusing system.