HJ-1A/B CCD与Landsat TM/ETM+植被指数的交互比较

利用5对同日过境的HJ-1A/B CCD和Landsat TM/ETM+影像对,研究了二者植被指数(NDVI,SAVI,EVI)之间的定量关系。选用其中的3对影像对作为实验影像,通过对均匀同质实验区对应的植被指数进行回归分析求出二者之间的转换方程,用未参与实验的2对影像对来验证所求转换方程的有效性,并对二者植被指数之间的差异进行了分析。结果表明：两种传感器对应的植被指数之间存在极显著的线性正相关关系,所求的转换方程具有较高的精度,可以利用转换方程将两种传感器的植被指数进行互为转换,有利于二者植被监测结果的互为补充,而两种传感器在光谱响应函数上的不同造成了二者植被指数间存在差异。

Cross Comparison of HJ-1A/B CCD and Landsat TM/ETM+ Multispectral Measurements for NDVI,SAVI and EVI Vegetation Index

The useful information provided by a single satellite is often not sufficient,for the use of multiresolution sensors from different satellites,we examined how well HJ-1A/B CCD sensor vegetation observations replicate Landsat TM/ETM+ vegetation observations.The study investigates the quantitative relationship between the vegetation indices of HJ-1A/B CCD and Landsat TM/ETM+ sensors,and more important,the difference in the vegetation observations between the two sensors.Three vegetation indices (the Normalized Difference Vegetation Index (NDVI),the Soil Adjusted Vegetation Index (SAVI) and the Enhanced Vegetation Index (EVI)) were calculated from both HJ-1A/B CCD and Landsat TM/ETM+ reflectance data.The quantitative relationship was revealed through regression analysis on the scatter plots of the vegetation index values for the same target of the two sensors based on three tandem images pairs.The models for the conversion between the two sensors were also obtained from the regression,then the accuracy of the obtained conversion models were evaluated based on the other two image pairs.The results show that there is a good agreement between the two sensor corresponding vegetation indices with the conversion models also have high accuracy,it will contribute to joint use of two sensors for vegetation monitoring by translated the vegetation index from one sensor to another based on the obtained conversion models.The relative spectral response function differences in the red and near infrared bands between the two sensors are believed to be the main factor which contvibute to their differences in vegetation observations.