Auto-Focus Algorithm for Moving Target Image
Auto-Focus Algorithm for Moving Target Image
复制标题
运动目标图像自动对焦算法
DOI：
10.1109/icig.2009.45
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Ni Jun
中科院分区：
文献类型：
--
作者：
Ni Jun
自动调焦技术是自动光学测量系统的核心部分。基于图像处理的自动聚焦算法是一个长期的研究课题。聚焦评价函数是用于测量图像是否聚焦的数学描述。现有的清晰度函数有时可以很好地用于静止图像，但在光学跟踪测量系统中，图像中物体的尺寸总是在变化。因此，这些锐度功能将失去其功能。本文提出了一种基于有限梯度归一化方法的有效锐度函数。该自动聚焦算法计算前帧和下一帧之间大于阈值的梯度的数量。该阈值根据图像特征是可变的。通过对几种聚焦评价函数的仿真结果进行比较，并结合实际应用，验证了该方法的可行性和有效性。
Auto-focus technology is the core part of the automatic optical measure system. Auto-focusing algorithm based on image processing is a long-standing topic in the literatures. The focus-evaluation-function is mathematical description used to measure whether the image is focused or not. The existing sharpness functions will work well for still image sometimes, but in optical tracking measure system, the size of object in image always changing. Thus, these sharpness functions will lose their function. In this paper, an efficient sharpness function based on normalization method of limited gradients is proposed. This auto-focus algorithm calculates the number of gradients bigger than a threshold between the front frame and next frame. This threshold is variable according to image features. According to comparison of the simulating results of several focus-evaluation-functions and combination with practical application, Practical applications illuminate the proposed approach is feasible and effective.