介绍Auto focus的文章，主要介绍了对焦技术，探测技术；包括频域分析、目标函数、目标函数效能验证、影像评估效能之因素、高斯低通滤波器参数的选取、自动对焦技术；以及相关实验结果与分析。-Introduction Auto focus of the article introduces the focus technology, detection technology　including frequency domain analysis, the objective function, the objective function performance verification, image assessment of the effectiveness of the factors, Gaussian low-pass filter parameter selection, auto-focus technology　and related experimental results and analysis.