Chris Data Products - Latest Issue

At the CHRIS/PROBA Workshop held last year in ESRIN a review was presented of various aspects associated with the CHRIS calibration [1]. The review addressed: first, the variation of the dark signal data, secondly, the use of the “generic” dark-field data sets for correcting analogue electronic offsets and, thirdly, the influence of the platform temperature variations on instrument response and hence radiometric calibration. It was concluded, first, that the errors introduced by gradual increase in dark signal through the mission life were negligible. Secondly, the use of the “generic” dark image data for correcting analogue offsets is probably acceptable for most land applications, where the scene albedo is relatively high. However, improvements in absolute offset errors may be worth pursuing for coastal scenes where the scene albedos are low, accepting that some images may experience saturation when imaging bright targets. Lastly, the temperature-induced pixel shifts significantly affect radiometric calibration and this effect required modelling within the image processing software. This paper reviews the changes that have been made to the data processing, following on from last year’s conclusions, and also addresses other information that has been added to the CHRIS data sets.