Automatic image orientation and DSM extraction from ALOS-PRISM triplet images

PRISM is a three-line scanner, on board of ALOS satellite, fully dedicated to the acquisition of high resolution panchromatic stereo imagery, for the generation of global terrain elevation data. Common processes of DSM generation required accurate ground control data, which may not be available in many areas were these imagery may be more useful. This paper presents a fully automatic method for ALOS-PRISM image orientation and DSM extraction without using conventional ground control points. It is based on the extraction of a relative DSM, which is adjusted by surface matching to the SRTM-DSM. This method proved to be accurate enough for the requirements of medium map scale production, such as 1:25.000.