大面阵彩色CCD航测相机的辐射定标  

Radiometric calibration of large area array color CCD aerial mapping camera

作　　者：修吉宏[1] 黄浦[1] 李军[1,2] 李友一[1] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所中国科学院航空光学成像与测量重点实验室,吉林长春130033 [2]中国科学院研究生院,北京100039

出　　处：《光学精密工程》2012年第6期1365-1373,共9页Optics and Precision Engineering

基　　金：国家863高技术研究发展计划资助项目(2009AA7010102)

摘　　要：以大面阵彩色CCD航测相机为研究对象,分析其成像过程,提出了影响相机辐射响应特性的各个因素,并以此为基础,建立了辐射响应特性模型。分别在暗场和使用积分球的条件下进行了辐射响应标定实验,通过组合更改输入辐亮度、曝光时间和CCD增益等因素对相机的辐射响应特性进行测量和分析。结果表明,相机R、G、B颜色通道随输入辐亮度变化的辐射响应特性并不相同,但在工作谱段范围内均呈线性变化趋势。采用最小二乘法对辐射标定数据进行拟合,一次多项式拟合结果的决定系数R2值均可达到0.999以上。当输入辐亮度不变时,相机输出图像灰度值随曝光时间或CCD增益的变化呈线性变化趋势,从而为其它工作条件下辐射响应特性曲线的推演奠定了理论基础。将相机辐射响应标定结果应用于相机调光功能,成像结果表明,获得的图像亮度适中,图像平均灰度值满足调光要求。Several kinds of factors affecting the radiometric calibration of a large area array color CCD aerial mapping camera were presented through analyzing the process of camera imaging. Then, a model for radiometric calibration was established. The experiments of radiometric calibration were performed by using integrating sphere and in the dark field, respectively, and outputs of radiometric response of the camera were measured and analyzed through combination of changing the input radiance, exposure time, CCD gain and other factors. The experimental results show that the characteristics of radiomet ric response for R, G and B color channels are different when the input radiance is changed, but it va ries linearly in the working spectral range. When the least square method is used to fit the calibration data of radiation, the goodness of fit for firstorder polynomial shows that the R2 is above 0. 999. Furthermore,when input radiometric luminance is constant, the output of the camera varies linearly with the exposure time or CCD gain, which lays the theoretical basis for the deduction of radiation response characteristic curves under the other work conditions. The data from radiometric calibration is applied to the exposure parameters, and experimental results indicate that the lightness of image is appropri ate and its average gray value satisfies the requirement for exposure.

关 键 词：航测相机 CCD相机 辐射定标 Bayer阵列 

分 类 号：V447.3[航空宇航科学与技术—飞行器设计] TN386.5[电子电信—物理电子学]