The Reserch Of Auto Focusing Algorithm And The Control Of Micro Platform Based On The Micro Vision System

As the size of the operation target is getting smaller and the demand of the operating precision is getting higher, the study of micro operating system enter a period of rapid development. Through analyzing the research background and the domestic and foreign development present situation of the micro operating system, the paper illustrates the importance of auto-focusing technology. The research direction is determined after talking about the problems in auto-focusing technology area.Our subject make the algorithm of focus depth as the key of auto-focusing. There exists several problems such as extreme value points in the focusing evaluation function,lack of flexibility in focusing window, and low accuracy in searching algorithm in the research. In this paper, the main research works are as follows:Firstly, compared with traditional evaluation function, the Robert function is improved by increasing the threshold, which reduces the local extreme value points and increase the steepness of the focus curve. A new method of dynamic selection focusing window is proposed, which divides the image into blocks. The change of gradient factor is to be as the standard of gradient variation, which satisfies the condition of the image sub-block, an then they are regarded as focusing window. This method has solved the problem that fixed focus window can’t find the object accurately. The improved mountain climbing method which combined the large step and small step has been proposed, and the focal plane can be found more accurately.Secondly, a new focusing evaluation function and focus search strategy are proposed for large range micro-vision system. The SUSAN operator of the time domain and the Discrete Wavelet Transform(DWT) of frequency domain are introduced and improved,and a new auto-focusing evaluation function is proposed by combining the two operators which have the advantages of single peak and steep peak on both sides of the peak. The focusing curve is divided into the flat area and the steep zone according to the characteristics of the focusing evaluation function. The large step size is set up in the flat area to achieve the rapid search, and the data is fitted by the Gauss curve in the steep zone.The new focus search strategy has improved on the aspects of the real time and accuracy.Finally, the platform of micro-vision system is established with a combination of upper computer and lower computer. The software is designed for the visual platform.To make sure the effectiveness of the proposed focusing strategy, the new method is verified based on the micro-vision system compared with the existing scheme.