大口径中波红外辐射特性测量系统标定

Calibration for mid-IR radiometric measurement system with big aperture

文中设计采用面源黑体对大口径中波红外辐射特性测量系统进行辐射标定,通过改变探测器积分时间的方式提高系统红外辐射强度测量的动态范围,得到全系统基于积分时间变量的辐射标定公式。分析了探测器像元的饱和特性,得到了像元的饱和边界条件。边缘像元的动态范围相对于中心像元扩大近50%。在1~3 ms积分时间范围内,探测器像元响应灰度值的均方根误差相对响应灰度平均值小于0.5%。标定过程中,随着积分时间的增加,像元响应灰度值的均方根误差变大,在测量时要采用相应的方法进行校正。通过实验数据验证,辐射标定公式的计算相对误差小于3%。

An extended-area blackbody is used to perform radiometric calibration on Mid-Wave Infrared Radiometric(MWIR) measurement system with big aperture. The method by changing the integration time of the infrared sensor is used to broad the measurement dynamic range of the system. Radiometric response model involving integration time of each cell is given and analyzed. The saturation characteristics of the cells of the sensor are analyzed and the dynamic range of edge cells is 50% broader than that of the inner cells. As the integration time is between 1~3 ms,the Root Mean Square Error(RMSE) of the measured count levels of the cell is less than 0.5% of the mean value. RMSE of responsibility increase as the integration time is extended,which should be corrected during measurement. The model is validated during a test in the laboratory,and the error of calibration result is less than 3%.