不同物距下的自动聚焦方法研究

Research on Auto-Focusing Approaches for Different Object Distances

目前对不同物距情况下的自动聚焦问题研究较少,为此提出了解决这一问题的自动聚焦方法。首先分析了不同物距的多个物体之间的成像关系和在不同物距情况下的图像清晰度评价函数的性质,然后提出了一种图像中心窗口的方法和用作图像清晰度评价函数的二维加权DCT系数的方法,最后采用一种改进的搜索策略对图像进行自动聚焦。实验结果表明,该方法可有效地对不同物距的图像进行自动聚焦。

Currently, there is a lack of investigating the auto-focusing technique for different object distances. This paper proposes an auto-focusing method for solving the problem. First, the imaging relation among many objects of different distances and the properties of image clarity evaluation function for different object distances are analyzed. Then, the image center window method and the two-dimensional weighted DCT coefficient method that is i applied to image clarity evaluation function are proposed. Finally, an improved search strategy is employed to focus the images. Experimental results indicate that the proposed method can effectively focus the images at different object distances.