Dem Generation with ALOSPRISM Stereo Data for Zijinshan Diggings

摘要

Digital Elevation Model (DEM) generation is one of the most important products of optical image data processing. The Japanese optical sensor ALOS/PRISM which was launched in January 2006 has stereo capabilities which can be used for a great number of applications and products. A cloud-free ALOS_PRISM scene combination covering 35km × 35km Zijinshan diggings testfield has been analysed. It comprises the nadir and backward views with a base-to-height ratio of 1.0. The pixel size on the ground is 2.5m. The bundle orientation was executed with the related module of PCI Geomatica V10.3.2 software package and the RMSE(m) of 2.96 in X,1.59 in Y were achieved in planimetry. This level of accuracy can be provided using the number of GCPs up to 16 which are distributed over the scene uniformly. Based on the scene orientation, a DEM of the area has been determined by an automatic image matching and PCI system yielded a DEM with 5m cell size. For the validation of extracted DEM, a group of GCPs selected over the testfield were utilized. In this analysis, GCPs were collected by GPS survey. This was done by ARCGIS 9.1 and mean square differences was obtained in the range of 3.93 to 12.5m. Moreover, A comparison between the extracted DEM of PRISM and ASTER GDEM(NASA) by using profile plot was conducted. In view of the overall trend, the two different curves of DEM were coincident. But The peak value for curve of ALOS DEM is more sharp due to the accuracy of ALOS DEM is more higher. In addition, ALOS DEM fits better where the variation of elevation is small. And the difference is more obviously where the variation is large. The Finally, 3 D views was generated using matched DEM and LANDSAT TM colour composite image in Zijinshan diggings area without problem. This was extremely useful in visualizing different parts of the area from different directions. And this is also proved to be of great help in identifying the tectonic geomorphology of Zijinshan diggings.