摘要
通过分析可见光面阵CCD的响应非均匀性,提出了一种适用于所有面阵CCD的响应非均匀性检测系统。利用该检测系统对全帧型面阵CCD485进行了辐射定标,建立了面阵CCD485数字图像的灰度值和积分球出口处辐照度之间的响应关系,并描绘了响应度曲线。从定标采集得到的数字图像可以看出灰度值有明显的跳跃,响应非均匀性已经超过了5%,在微光拍照时将严重影响成像的质量,所以必须进行校正。根据面阵CCD响应度曲线来选择非均匀性校正算法,考虑到面阵CCD485的响应度为线性,这里采用了两点校正算法,求出面阵CCD各个像元的校正因子(增益和偏置),并存储到校正矩阵中,通过乘积加法运算把各个像元的信号校正成面阵CCD的平均信号值。实验结果表明,两点校正算法使面阵CCD485的响应非均匀性降低到原来的1/10左右,是一种实用有效的校正方法。
Through analyzing response non-uniformity of visible light area CCD,a kind of system that is used to response non-uniformity detection had been presented,and it is applied to all kinds of area CCD.After radiation scale was done for area CCD485with this system,the respond relation was established between the gray value of digital image and radiation luminance which integration sphere exported,and responsibility curve was also described.From the digital image that can be gathered,it can be find out the gray value have obvious jump,response non-uniformity has exceeded 5%.When taking pictures under weak light,it will be serious to affect the quality of pictures,so must be rectified.Correction algorithm is selected according to the responsibility curve of area CCD.Because of the area CCD485＇s responsibility is linear,so here have adopted two-point correction algorithm,calculate the correction factors（gain and offset）of all pixels,and put them into correction matrix.Through multiplication and addition operation,the signal of every pixel is rectified into the average signal of area CCD.Experiment result shows that two-point correction algorithm makes response nonuniformity of CCD485arrive original 1/10,it is a practical effective method of correction.
出处
《液晶与显示》
CAS
CSCD
北大核心
2010年第5期759-763,共5页
Chinese Journal of Liquid Crystals and Displays
基金
国家"863"计划基金资助项目(No.863-2-5-1-13B)
关键词
面阵CCD
响应度
非均匀性校正
两点校正算法
area CCD； responsibility； non-uniformity correction； two-point correction algorithm；
