DM6437自动对焦的研究与实现

Research and Realization of Auto Foucs of DM6437

视觉检测技术作为一种新型的测量手段具有很多其他测量方法所无可比拟的优点,因而被广泛应用于仪器仪表自动化领域。采用DSP完成对图像信息的采集和分析处理则大大提升了产品的自动化水平和集成度。作为视觉产品,自动对焦是一项非常能够体现智能化水平的功能,被用于很多精密光电测量的仪器。首先详尽介绍了基于DM6437为核心的硬件视觉平台基础上,从光学角度对图像的离焦和正焦做了阐述。而后分别就灰度方差、信息熵、频域分量、边缘梯度等几个方面展开论述,讨论建立了各自清晰度评价函数的数学模型。通过PWM操控直流电动镜头来实现自动对焦效果,并具体分析了不同控制方式下最佳正焦位置的搜索方法,以及基于此平台所开展的自动对焦的研制工作成果。

As a new technique vision examination technology has many unsurpressable excellences and was used in the automactic instrument and apparatus widely. The image information collected by digital signal processor can improve the intellectualized level of product. As a very important function auto focus（AF） was always a essential symbol in the design of product. AF also play a influential role in precise electro-optical survey. A platform on which the processor DM6437 is the core chip at frist is introduced. Then out of focus and fit for focus were elaborated from the optical side. Some models such as the gray of gradation, information＇s entrogy, frequency weight and the intensity of edge were discussed, and clarity evaluation function was build. AF was realized by electrical lens, and the effect of AF was showed.