基于DSP的自动聚焦系统
Auto-focusing system based on DSP
王凤宇 1王睿 1张广军1
作者信息
- 1. 北京航空航天大学,仪器科学与光电工程学院,北京,100083
- 折叠
摘要
通过对基于空域分析的聚焦评价算子的对比,选择了基于Sobel梯度的Tenengrad函数作为系统的聚焦评价函数,该函数具有聚焦精度高、成像清晰的优点,但计算量大,不适合实时计算.根据DSP的运算特点,对Tenengrad函数进行了改进,提出了x/y向Tenengrad函数概念.通过实验证明,改进后的函数在不损失原函数聚焦精度的情况下,每幅图像的聚焦判据的计算时间减少为25ms,是原来聚焦判据计算时间的1/35,以此作为聚焦评价函数,在TMS320DM642平台上通过对视频驱动、UART驱动的开发,实现了可变焦摄像机的实时自动聚焦.
Abstract
The focus evaluation functions on the basis of spatial domain are analyzed. Then,Tenengrad function based on Sobel operator is chosen as the focus evaluation function. Tenengrad function is improved to overcome the great computation cost and a xly Tenengrad function which can be real-timely implemented in the Digital Signal Processing (DSP) platform is put forward. Experimental results indicate that with almost the same focusing precision,the focusing computation time for per image of 768x576 is within 25ms,which is one thirty-fifth of that of the classic Tenengrad function. By finishing the video driver and UART driver in the TMS320DM642 platform,an auto-focusing system comprising xly Tenengrad function and global searching algorithm is set up successfully.
关键词
自动聚焦/评价函数/Tenegrad函数/DSPKey words
automatic focusing/evaluation function/Tenengrad function/DSP引用本文复制引用
出版年
2007
NETL
NSTL
维普
万方数据