空间光学遥感器的辐射传递特性与校正方法

Radiation transfer characteristic and calibrating method for space optical remote sensor

由于受大气背景辐射和自身光电响应特性的影响,对地观测的空间光学遥感器所获取的原始数字图像与景物真实的辐射亮度图像相差甚远[1],为此,通过对光学传感器辐射定标,建立了入射辐射亮度与输出图像灰度间的辐射响应函数,来实现辐射亮度图像的反演和辐射校正。根据光学遥感器辐射传递转换过程,采用泰勒级数和矩阵函数模型描述了"辐射响应函数"的物理概念,并提出了多次回归分析求解矩阵方程获得辐射校正系数的方法。在进一步的实验中,结合积分球扩展辐射源对某型号民用相机进行实验室辐射定标,获得了该相机的辐射响应函数。实验结果表明,该方法可行且实用。最后,对实验获得"辐射响应函数"的物理意义以及辐射定标精度等问题进行了讨论。

Being influenced by background radiation and opto-electrical response characteristics, the original digital image acquired by space optical remote sensor is very different from radiance image of real target. Therefore, the response function between input radiance and image grey level is established by calibrating the optical remote sensor to perform radiance image retrieval and radiation calibration. According to radiation transfer and conversion process of remote sensing signal, the physical concept of radiation response function is described using the model of Taylor progression and metric function, and a multiple regression analysis method for solving metric function is put forward. By applying a integrating sphere expanded radiation source, a civil camera is calibrated in Lab, and the response function is obtained. The result shows that the proposed method is feasible and practical. At last, the problem about physical meaning of radiation response function and radiometric precision are discussed.