摘要
针对手机等移动终端设备中的摄像模组,提出了一种嵌入式自动聚焦控制系统。该系统以AD5820作为聚焦电机的驱动IC,以OV5642作为图像传感器,利用68013单片机进行数据处理并控制驱动IC调整镜头的位置,完成准确自动聚焦。系统通过控制音圈电机带动镜头行程变位,获取一系列图像;计算每幅图像清晰度评价值构成清晰度评价曲线;采用梯度函数作为图像清晰度评价标准;并用全程搜索的方式找到图像清晰度最大值时镜头的位置,从而达到聚焦的目的。实验验证显示,系统的聚焦分辨率能达到5～10μm,响应速度小于70ms。自动聚焦实物拍摄图像清晰,能够很好地满足摄像模组自动聚焦的需求。
Abstract： A control system for embedded auto-focusing camera modules is proposed for mobile phones and other mobile devices. For the purpose of accurate auto-focusing, the system makes use of an AD5820 as the driver IC for a focusing motor, the OV5642 as an image sensor,and the 68013 micro- computer unit as the data processing and controlling driver IC for lens position adjustment. In auto focusing, the system obtains a series of clear images through controlling a voice coil motor to change lens positions at first,and a focusing evaluation curve is formed through calculating the definition evaluation for each image. Then, the image definition is evaluated by using gradient function as evaluation standard, and the lens position is found by the full search when the image definition comes to the maxi- mum value. According to the experiment, the system can offer the focusing resolutions of 5- 10 um and response time less than 70 ms,which shows that the system has good automatic focusing performance, and can satisfy the requirements of automatic focusing system for the camera module.
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2012年第10期2222-2228,共7页
Optics and Precision Engineering
基金
国家自然科学基金资助项目(No.61275003
No.60808015)
粤港关键领域重点突破项目(No.200920522800017
2007A010301004)
深圳市基础研究计划资助项目(No.JC201005310719A)
