CCD光谱辐射计的非线性特性建模与校正

Nonlinearity Characteristic Modeling and Correction of CCD Spectroradiometer

采用自主研制的CCD光谱辐射计,对CCD探测器的积分时间和光强灰阶2个关键参数的非线性参数依赖特性进行实验与建模,给出CCD的微分非线性量化表征函数,并以此为基础实现CCD在多级尺度下自动积分时间调整测量的非线性修正.以激光作为输入光源进行双参数调节响应特性测试,并对CCD光电转换非线性特性进行分析.根据数据集曲线族的结构特征重构数据表征空间,在新的表征坐标下进行CCD的参数依赖非线性变化关系的拟合建模.结果表明,在多级尺度范围内,该模型能够通过2个参量描述CCD光谱辐射计产生的非线性偏差变化的精确函数关系,即实现了相关双参数在CCD光电转换过程中产生非线性偏差现象的精准量化表征.采用该模型进行非线性校正后与监测功率计进行比较,发现该模型能够有效地将非线性偏差降低至±2%以内.

The experimental and modelling research on the parameter-dependence nonlinearity of two key parameters(integration time and responsed gray level)of the CCD detector was carried out by using the self-developed CCD spectroradiometer.By giving the CCD′s characterization function of differential nonlinearity,the nonlinear correction was achieved for automatic integration time adjustment measurement of CCD spectroradiometer in multi-scale on the model function.The response characteristics of two-parameter adjustment were tested by the laser beam incidence,and the nonlinear characteristics of CCD photoelectric conversion were analyzed.The data coordinates is reconstructed according to the structural features of the data sets curves,and the fitting model of nonlinear change relationship with the dependent parameters of CCD is built in the new representation coordinates.The results show that,in the multi-scale range,the model can describe the precise functional relationship of the nonlinear deviation caused by CCD spectroradiometer through two parameters,that is to say,the precise quantitative characterization of the two-parameter correlation nonlinear deviation of CCD photoelectric conversion is achieved.The comparison between the response value after nonlinearity corrected by the fitting model and the monitoring value of power meter shows that the model can effectively reduce the nonlinearity deviation to less than±2%.