对焦算法实现总结.doc

本文对数码相机自动对焦系统设计中的几个关键技术—自动对焦搜索方法、评价函数、对焦窗口和镜头控制进行了深入的研究。对传统爬山算法的运行 方式和存在问题进行了全面的分析，在此基础上提出了对爬山算法的改进方法。为了提高自动对焦的速度和精度，采用图像的绿色分量和梯度函数修正形式计算评价函数，采用四点选择法选择对焦窗口，通过大量实验获取更精确的控制参数对镜头进行精密控制。整套算法在基于多媒体微处理器ZR36451BGCF搭建的数码相机平台上实现。通过对算法的改进，在没有增加硬件成本的基础上，用更加合理的软件实现了自动对焦系统的大部分功能，提高了系统的稳定性和可行 性。

自动对焦算法AF，此为相机里的快速对焦算法，供软件 人中学习

1) Basic concepts of Auto Focus Algorithm 1.1) AF Detection methods There are two focus detection (AF) methods. 1) Distance detection method. 2) Contrast detection method. 1.1.1) Distance detection method The distance detection method is that the camera use AF module for detecting distance for main objects. If the camera is used this AF method, it will not need to use CCD to detect object’s contrast. There are three types of AF modules. 1. Active AF module 2. Passive AF module 3. TTL AF module 1.1.1.1) Active AF module Active AF systems measure distance to the subject independently of the optical system, and subsequently adjust the optical system for correct focus. There are various ways to measure distance, including ultrasonic sound waves and infrared light. In the first case, sound waves are emitted from the camera, and by measuring the delay in their reflection, distance to the subject is calculated. Polaroid cameras were known for successfully applying this system. In the latter case, infrared light is usually used to triangulate the distance to the subject. An exception to the two-step approach is the mechanical autofocus provided in some enlargers, which adjust the lens directly. 1.1.1.2) Passive AF module Passive AF systems determine correct focus by performing passive analysis of the image that is entering the optical system. They generally do not direct any energy, such as ultrasonic sound or infrared light waves, toward the subject. (However, an autofocus assist beam of usually infrared light is required when there is not enough light to take passive measurements.) Passive autofocusing can be achieved by phase detection or contrast measurement.

自动对焦相机 我的自动聚焦算法的开放源代码实现，用于带有图像处理算法的常规显微镜。

对焦算法测试组图，可用以自动对焦算法的测试

提出一种液晶透镜爬山自动对焦算法。液晶透镜是一种可电控调焦透镜,具有良好的透镜性能。传统玻璃透镜成像系统中的爬山法自动对焦功能一般需要音圈马达带动透镜使之不断移动来寻找最佳清晰像面位置。而所提算法的自动对焦则是通过改变电压来完成的,整个对焦过程不需要任何的机械移动即可实现大范围对焦,使对焦系统的小型化成为可能。实验结果表明,液晶透镜的对焦性能良好,成像解析度高。

针对平面样品的大规模显微图像采集，提出了一种预测的快速对焦方法

相机的自动对焦的算法（auto focus），对不同的镜头的对焦算法