MOS and SEASAT image geometric corrections

Results of studies to generate precise orthoimages from MOS-MESSR data in the visible spectral range and SEASAT-SAR data in the microwave range are reported. The raw MOS-MESSR image has four spectral bands, with an interband misregistration of three to four pixels. A methodology for orthoimage generation directly from each band of the raw image is described. For thematic applications with SEASAT images, most users have access only to slant range or ground range image products, which are often not georeferenced or geocoded with a standardized pixel spacing. The same methodology for creating orthoimages has been adapted for spaceborne SAR images, and tested with a ground range SEASAT image. The analysis of the sensor and satellite motion geometries and the use of a photogrammetric approach allows a rigorous mathematical model for the geometric correction and the rectification of the raw images to be derived. The final accuracy of the geometric corrections is about 25 m for both data types, using only six ground control points