一种适合照相手机的快速自动曝光算法  

An Efficient Auto-exposure Algorithm for Camera Phones

作　　者：肖鸿[1] 

机构地区：[1]长沙理工大学电气与信息工程学院,湖南长沙410076

出　　处：《现代电子技术》2007年第24期119-120,126,共3页Modern Electronics Technique

摘　　要：随着高分辨率照相手机的迅速普及,用户对成像质量的要求越来越高。精确地控制照相手机的曝光量成为提高成像质量的关键参数之一。基于成本和空间的考虑,当前主流照相手机中应用最广的自动曝光算法主要根据18%的反光率来获得一个合适的曝光值。如果景物中存在大面积的高反光率的表面(如白雪或沙滩)或低反光率的表面(黑色背景),根据18%的反光率所得到的曝光值会过暗或过亮。针对此缺陷提出了一种改进的自动曝光算法以获得更为准确的曝光值。实验结果表明新算法在有效提高对困难景物的成像质量的同时并没有增加太多的计算量。As high- resolution camera phones become accessible to wider population, users are expecting better image quality comparable to that of entry- level Digital Still Cameras （DSCs）. The performance of the embedded Auto- Exposure （AE） algorithm becomes a critical factor that impacts the overall image quality. Due to cost and space limitations, most mainstream camera phones today still employ a variety of simple AE algorithms assuming the averaged surface reflectance in a scene is close to an 18% gray surface. However,these algorithms will record underexposes images for scenes with largely high reflectance surfaces （such as snow or beach） or largely low reflectance surfaces （dark background）. This paper proposes a modified AE algorithm to address this problem and the experimental results showed improve image quality under these challenging circumstances with negligible computational overhead.

关 键 词：自动曝光 照相手机 数码相机 曝光校正 

分 类 号：TH741.4[机械工程—光学工程]