Merge of sub-images from two PAN CCD lines of Kompsat-3 AEISS

The Kompsat-3 Advanced Earth Imaging Sensor System (AEISS) camera contains two PAN CCD lines for a larger swath width. Merge of sub-images from individual CCD lines requires precise camera calibration before launch as well as in-flight calibration with a number of ground control points to determine the geometric relations between the CCD lines. Even with accurately determined sensor alignment parameters, there can still be exterior effects such as those associated with the ephemeris and terrain elevation. We generated a grid of tie points over the sub-images based on the physical sensor modelling and then evaluated the impacts of sensor alignment, ephemeris effects, and terrain elevation on the coordinate differences between the tie points. This enabled us to develop a procedure to precisely merge the sub-images into a single image. An experiment with three Kompsat-3 images produced successful results and displayed negligible image discrepancy in the overlap area.