Engineering Commons^™

Fast And Accurate Autofocus Control Using Guassian Standard Deviation And Gradient-Based Binning, Peter Dimeo, Lu Sun, Xian Du

Mechanical and Industrial Engineering Faculty Publication Series

We propose a fast and accurate autofbcus algorithm using Gaussian standard deviation and gradient-based binning. Rather than iteratively searching for the optimal focus using an optimization process, the proposed algorithm directly calculates the mean of the Gaussian shaped focus measure (FM) curve to find the optimal focus location and uses the FM curve standard deviation to adapt the motion step size. The calculation only requires 3-4 defocused images to identify the center location of the FM curve. Furthermore, by assigning motion step sizes based on the FM curve standard deviation, the magnitude of the motion step is adaptively controlled according …