Block adjustment of multistrip ALOS/PRISM images

ALOS (Advanced Land Observing Satellite) /PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) is an optical sensor that is able to acquire forward, nadir and backward images simultaneously. This characteristic is useful for 3-D positioning as it may acquire along-track stereo images. A number of studies have been reported on the block adjustment of PRISM along-track stereo images. However, relatively few studies have discussed the block adjustment of PRISM along-track and across-track stereo images. The purpose of this study is to evaluate the geometric accuracy for the block adjustment of multistrip PRISM images in different combinations. The major works include the automatic tie-point matching, bundle block adjustment and accuracy analysis. First, we use ERDAS LPS to extract the tie points automatically between along-track and across-track images. Then, we perform the bundle block adjustment using ephemeris data and ground control points. Finally, the check points are utilized to assess the geometric accuracy. The test area is located in the northern part of Taiwan. Two strips of PRISM level 1A images with OB1 (forward, nadir and backward images) and OB2 (nadir and backward images) modes are selected in the experiment. The geometric accuracy assessments compare the result of along-track stereo images, cross-track stereo images and all images. The multi-view PRISM images may improve the geometric capability for block adjustment. Therefore, the block adjustment of multi-view images is beneficial to terrain generation.