A Strip Adjustment Approach for Precise Georeferencing of ALOS Optical Imagery

Precise georeferencing is one of the prerequisites for orthoimage generation from high-resolution satellite imagery. This requires the availability of a small number of GCPs that have to be visible in each scene. In this paper, it is shown how the number of GCPs required for the precise georeferencing of Advanced Land Observation Satellite (ALOS) imagery can be reduced by up to 90% using a generic pushbroom sensor model and strip adjustment while still achieving an accuracy of better than 1 pixel. A fully automatic work flow requiring an existing digital orthophoto and a digital elevation model (DEM) is also presented. Using an orthophoto mosaic generated from Landsat-7 panchromatic imagery for automatic GCP measurement, pixel-level accuracy can be achieved for images from the Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2) instrument. For images from the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM), the accuracy of the automated procedure is only about 2 pixels due to the poor resolution of the orthoimage, compared with PRISM.