Research On The New Method Of The Spectral And Radiometric Calibration Of The Imaging Spectrometer

Imaging spectrometer is a new type remote sensor which can collect both the image and the spectral information of the scene. The calibration of the imaging spectrometer includes the spectral calibration and the radiometric calibration. he spectral calibration is used to determine the central wavelength, spectral width, and the radiometric calibration is used to determine the radiance response of each channel, linearity of the response and the stability of the response. According to the characteristic of and the application of the imaging spectrometer, the new method and technique of the spectral calibration and the radiometric calibration are studied. The primary work in this paper is as followed:1 The new method by using the diffuser to calibrate the imaging spectrometer is studied. The method of using the standard detector as the radiometric standard and using the white diffuser as the extent source is modeled, and the effect of the geometry parameters of the calibration and the parameters of the imaging spectrometer on the relative electron number is computed and analyzed. The results indicate: when the slit is perpendicular to the meridional plane, the illuminating distance is longer, the illuminating angle is larger, the observation of the imaging spectrometer is smaller, the electron number collected by the different pixels of the same spectral channel is more uniform, but the electron number is relative less. When the illuminating distance ranges 0.5m~1.25m, the illuminating angle is less than 12?, the relative electron number changed caused by the distance changed 1mm and angle changed 0.5? is less than 1%.2 The new method to calibrate the imaging spectrometer is studied. The spectral sample interval of the imaging spectrometer calculated and the atmosphere absorption of the atmosphere are used to calibrate the central wavelength and spectral width of the channels of the imaging spectrometer. Comparison was made between the spectral calibration result and a spectrometer which has high spectral resolution and the results are improved. The results indicate that the spectral calibration of this method can achieve precision of 1nm.The standard lamp and the simulated radiance by the software are used to calibrate the fiber spectrometer, then the imaging spectrometer is calibrated by the fiber spectrometer and the white diffuser respectively. The calibration coefficients using two methods are obtained, and the results are analyzed.3 The correction of the uniformity of the radiometric characteristic of the imaging spectrometer is studied. The pushbroom of the imaging spectrometer is simulated by the rotating stage, and the image obtained is processed. The results indicate: the frame frequency of the CCD of the imaging spectrometer matches the rotating speed of the rotating stage. The images achieve the planned quality after the correction of the uniformity. The spectral information collecting capability of the imaging spectrometer is validated by getting the color fused image.