数字自动对焦中的搜索算法研究

设计了综合的对焦搜索算法。利用对焦范围上下限、预判定搜索方向、评价函数值连续下降两次才认为越过对焦曲线峰值与设定下降阈值,改进了爬山搜索法。在对焦镜偏离光学对焦范围情况下,利用对焦范围上下限与预判定搜索方向,改进了穷举搜索法;对完焦后再校验场景是否正确,光照低于设定阈值时则关闭搜索,可提高抗干扰能力;利用成像曲线,变倍镜移动时能快速地对焦。实验表明:采用综合搜索算法能够实现准确、快速的对焦,避免搜索陷入局部峰值,具有良好的抗干扰与稳定性。

Research on search algorithm for digital auto-focus

A comprehensive focusing searching algorithm is designed.The traditional climbing search algorithm is improved by using upper and lower limits of focus range,pre-determining searching direction,and considering that the evaluation value go across the peak of focusing curve after second decline and setting the decline threshold.The traditional endless searching method is improved by using upper and lower limits of focusing range,pre-determining searching direction when the focusing lenses deviated from the focusing range.The scene is checked again to prevent it from errors due to interference after the focusing is completed.The search is disabled when the illumination is below the threshold.Focusing is quickly achieved by using image curve when the zoom lens are moving.Experiments show that using the comprehensive searching algorithm accurate and fast focusing can be achieved,prevents the searching from falling into the local peak,and have good anti-jamming and stability.