A Realtime Auto-focus Microscope System Based on a Visual Programming Software

With the development of medical technology and automatic control, researchers have been working on autofocus for decades in order to reduce the errors caused by artificial factors. The core of auto-focus technology is combining the image sharpness evaluation function and one-dimensional function optimization. When the function gets the highest value, the system is in focus position. Several classical sharpness evaluation curves and optimization algorithms are compared in this paper to analyse their advantages and disadvantages, and this paper proposes a microscope auto-focus method with image gray histogram average and hill-climbing algorithm. An experiment is conducted by using an NI, a stepping motor, a mobile load platform, a microscope, a shooting unit and a computer monitor. The control system is built with Labview visual programming software that can easily analyse and process signals. The experimental results show that the proposed microscope auto-focus method in this paper is better than those existing techniques by enhancing the accuracy and speed of auto-focus.