相机参数可变的齐次多项式色度特征化模型  

Homogeneous Polynomial Model for Colorimetric Characterization of Camera with Variable Settings

作　　者：方竞宇 徐海松[1] 汪哲弘[2] 吴晓玟[1] 

机构地区：[1]浙江大学光电科学与工程学院现代光学仪器国家重点实验室,浙江杭州310027 [2]杭州市质量技术监督检测院建材电器中心,浙江杭州310019

出　　处：《光学学报》2016年第8期301-308,共8页Acta Optica Sinica

基　　金：国家973计划(2013CB328802)

摘　　要：基于相机的成像原理,建立了不同拍摄参数下响应值之间的转换方程,提出了一种基于齐次多项式回归的色度特征化模型,克服了传统多项式模型非线性外插造成的误差。对Nikon D3x数码相机进行了拍摄参数变化的色度特征化实验,分析了不同项数对特征化精度的影响。实验结果表明,齐次多项式模型适用于描述拍摄参数可变的相机色度特征化,且项数以6、7项为宜;在4种色温和7种照度构成的28种LED光源下的实验中,在色温不变、照度变化的光照下其颜色预测精度优于1.5CIELAB色差单位,与固定参数、固定光照下多项式模型的精度相当,而在色温和照度同时变化的情况下其平均色差小于2.0CIELAB单位,可以满足相机应用的色度精度的性能要求。Based on the imaging principle of cameras,a transformation equation among response value under different capture settings is established,and a colorimetric characterization model based on the homogeneous polynomial regression is proposed,which avoids errors caused by the nonlinear extrapolation in the traditional polynomial model.A Nikon D3 xdigital camera is employed to conduct the colorimetric characterization experiment under variable capture settings and the effect of different numbers of terms on characterization accuracy is analyzed.The experimental results show that the homogeneous polynomial model is applicable to describing the colorimetric characterization of cameras with varible capture settings,and it shows the best performance with 6or 7terms.In the experiment of 28 kinds of LED light resources with 4kinds of color temperature and 7illumination levels,but under fixed color temperature and variable illumination,the predicted color accuracy is superior to 1.5CIELAB units and it is comparable to the accuracy from the polynomial model with fixed parameters and light sources.In contrast,under the simultaneous change of color temperature and illumination levels,the average chromatic aberration is less than 2.0CIELAB units,which fulfills the colorimetric accuracy requirement in the practical application of cameras.

关 键 词：视觉光学 色度学 色度特征化 齐次多项式 数码相机 

分 类 号：O432.3[机械工程—光学工程]