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CCD相机数据的应用是CBERS-02为国民服务的重要部分,而提供长期稳定的绝对辐射定标系数是其应用的关键.试验场定标法是一种有效的方法,但该方法需要地面同步测量数据,提供的定标系数数量不可能很多,且该方法不能对历史数据进行定标.交叉定标是解决该问题的有效方法之一.但目前该方法对同步测量数据的依赖性较大.模拟分析各种因素对光谱匹配因子的影响.结果表明地物的光谱匹配因子受大气条件、传感器观测几何条件及地物类型的影响.但是在环境一样时,不同时期或测区获取的同类型地物的光谱匹配因子相对稳定,可代替同步测量数据来模拟光谱匹配因子.基于该方法,利用MODIS数据对CCD数据进行交叉定标,研究发现CCD各波段都存在偏移量,传统的单点定标法不适用于CCD的辐射定标.文中以多点交叉定标法计算获取各波段偏移量,并获得了时间序列图像的定标系数,发现CCD传感器响应随时间衰减.
The application of CCD camera data is an important part of CBERS-02 for national service, and the key to its application is to provide long-term stable absolute radiation calibration coefficients. The calibration method of the test site is an effective method. However, this method needs the data of the ground synchronization measurement to provide a large number of calibration coefficients, and the method can not calibrate the historical data. Cross-scaling is one of the effective ways to solve this problem. However, the current method is more dependent on the synchronous measurement data. Simulation analysis of various factors on the spectral matching factor. The results show that the spectral matching factor of ground objects is affected by the atmospheric conditions, the geometrical conditions of the sensors and the type of ground objects. However, when the environment is the same, the spectral matching factors of the same type of features acquired in different periods or in the measurement area are relatively stable, and instead of the synchronous measurement data, the spectral matching factors can be simulated. Based on this method, MODIS data is used to cross-calibrate the CCD data. It is found that there is an offset in each CCD band. The traditional single-point calibration method is not suitable for the CCD radiation calibration. In this paper, multi-point cross-calibration method to obtain the offset of each band, and obtained the time-series image scaling coefficient, found that the CCD sensor response decay with time.