Micro-vision auto focus by image analysis

Edge gray-based evaluation function was defined, and an improved differential Laplacian and threshold value-based filter were used to reduce the errors of image focusing and a threshold value as a parameter was introduced. Microscopes were focused automatically by the evaluation function and some measures were adopted in the process. Medium and homomorphic filtering were employed to filter the noises from microscopic images to improve the quality of microscopic images. A method was designed to evaluate the clarity of the images. A frame difference technique with a limit was implemented to distinguish the foreground from the background of the microscopic images and reduced the noise effects and the foreground changes. Results show that the method with a high precision is stable and reliable.