Microscope Auto-focus System Design And Application

Auto-focus is used in imaging system more and more. It's crucial to many application areas where involve with imaging system, such as daily life, science research, military affairs. At present, many theories and methods of Auto-focus have been present. However, the application of Auto-focus on some imaging system is not mature and still need to be greatly researched. An Auto-focus system design include the focus measure design, the control system design, the carrying out mechanism design, the power supply design and the user interface design. In this paper, we designed an Auto-focus system applying to microscope. It works as follow: First, the Auto-focus system captures video signal by CCD image sensor. Then, the video signal passes through a band-pass filter and an analog integrator. The microprocessor samples the result of the integrator by an analog-to-digital converter and then judge whether the lens is in focus. If the lens is not in focus, the microprocessor will control the lens to be in focus by moving the step motor. The test result indicated that the system is stable and the Auto-Focus time is acceptable. This Auto-Focus system is compact, rapid focusing, stable and low cost, so it can be widely used.The thesis is divides into several chapters. (1) Firstly, the paper briefs the research status quo, the principles and methods of Auto-focus technology. (2) Designed a focus measures based on a filter of CCD video. (3) Thirdly, designed the hardware system of the Auto-focus system using with microscope. (4) Designed the software system of the Auto-focus system. (5) Tested the Auto-focus system minutely. (6) At the end of the paper, I will prospect the future of the technology and analyze the technique needed to be research.Based on the analysis of Auto-focus theory, this paper stressed product design and implement. Meeting the requirement, applying correlative theory to microscope system, this paper developed a stable and practical Auto-focus system.