ACQUISITION METHOD OF HIGH ACCURACY GROUND CONTROL POINTS FOR HIGH - RESOLUTION SATELLITE IMAGERY

摘要

Currently, high-resolution satellite imageries as less than 1m resolutions are used in many fields. For example, land use mapping, urban planning, disaster monitoring, and so on. They are expected to be overlaid with other GIS data and updating existing maps. Therefore, high accurate geometric correction is necessary to analyze high-resolution data. However, it is difficult to acquire highly accurate ground control points (GCP) and the corresponded image control points (ICP). Because, acquisition of the high accuracy ICP by using visual interpretation is very difficult. In this study, acquisition method of high accuracy GCP and the corresponded ICP was discussed. Field surveying by kinematic using GPS was used for generating polygon data for GCP. And center of gravity of the polygon was used as GCP. Error of coordinates in GCP dataset by field surveying can be decrease by calculating center of gravity of the polygon. Calculation results showed less than 0.1 m error. It was enough accuracy as GCP. An efficiency of center of gravity calculation for high accurate ICP were evaluated by generating simulation images from GCP polygons. The simulations were carried out under some conditions as follows ; – Shape of GCP polygon. – Elevation difference in GCP Polygon. – Off-nadir angle of satellite image. – Error in classification. The simulated images were generated from GCP polygons by transformation using collinearity equation. Center of gravity as ICP were also calculated the simulated polygon image. The results showed shape of polygon and off-nadir angle influence to accuracy of ICP. Required accuracy were satisfied under the condition that “off-nadir angle” ranges from 0°to 10°and “flat area”.