基于订正ALPHA差值谱的热红外温度与发射率分离算法

与可见光遥感不同，热红外传感器测得的辐射亮度值是温度和发射率的函数，因此，对于热红外遥感，温度和发射率的分离是一个关键问题？本研究从普朗克方程的维恩近似出发，定义并推导出与温度无关的ALPHA差值谱，并进一步提出消除维思近似影响的修正项．以此为基础，在不考虑大气下行辐射影响的条件下，借鉴ALPHA导出发射率法和ASTERTES算法的优点，提出一个新的发射率温度分离算法．与现有发射率温度分离算法相比，该算法的优点是原理清楚，流程简单，求解速度快，结果精度高，并且适用的温度和下垫面范围宽．

THERMAL INFRARED TES ALGORITHM BASED ON CORRECTED ALPHA DIFFERENCE SPECTRUM

Different from visible spectral remote sensing, thermal infrared radiances vary with both temperature and emissivity. Hence, for thermal infrared remote sensing, the separation of temperature and emissivity is a key problem. In this study, by starting from WIEN’s approximation, ALPHA difference spectrum was defined and derived which is independent of temperature. Then, a correction item to remove the influence of WIEN’s approximation on ALPHA difference spectrum was developed. On these bases, a new temperature and emissivity separation algorithm was developed under the condition of neglecting the effect of atmosphere downwelling radiation, which combines attractive features of ALPHA derived emissivity method and ASTER TES algorithm. Compared with current TES algorithm, the new algorithm is fast, simple and precise. It can be used for wide temperature and surface type ranges.