Cross Calibration of CBERS-02 CCD Image Based on the Pseudo-invariant Reflectance Targets

This paper illustrates a cross calibration method based on the pseudo-invariant reflectance targets.It can use the images acquired at along interval period,only there is the pseudo-invariant reflectance targets in two images.Firstly,the reflectance was retrieved from the images with known calibration coefficient using MODTRAN model.Secondly,the radiance of the same pseudo-invariant targets in image with unknown calibration coefficient is calculated.Finally,the calibration coefficient is calculated.This method was used on CBERS-02 CCD image calibration.Then the CBERS-02 image using different calibration coefficient and ETM+ image were atmospherically corrected using 6S model.The spectral curve of the higher reflectance ground object in CBERS-02 image using different coefficient was accorded to the spectral of the same targets in ETM+ image.Under the low reflectance ground object,the single point calibration coefficients error is relatively great rather than the double point calibration coefficient.The vegetation information was enhanced in the image atmospherically corrected using the double points calibration coefficient.