ACQUISITION METHOD OF HIGH ACCURACY GROUND CONTROL POINTSFOR HIGH - RESOLUTION SATELLITE IMAGERY

摘要

Currently, high-resolution satellite imageries as less than 1m resolutions are used in manyrnfields. For example, land use mapping, urban planning, disaster monitoring, and so on. Theyrnare expected to be overlaid with other GIS data and updating existing maps. Therefore, highrnaccurate geometric correction is necessary to analyze high-resolution data. However, it isrndifficult to acquire highly accurate ground control points (GCP) and the corresponded imagerncontrol points (ICP). Because, acquisition of the high accuracy ICP by using visualrninterpretation is very difficult. In this study, acquisition method of high accuracy GCP and the corresponded ICP was discussed.rnField surveying by kinematic using GPS was used for generating polygon data for GCP.rnAnd center of gravity of the polygon was used as GCP. Error of coordinates in GCP datasetrnby field surveying can be decrease by calculating center of gravity of the polygon. Calculationrnresults showed less than 0.1 m error. It was enough accuracy as GCP.rnAn efficiency of center of gravity calculation for high accurate ICP were evaluated byrngenerating simulation images from GCP polygons. The simulations were carried out underrnsome conditions as follows ;rn– Shape of GCP polygon. – Elevation difference in GCP Polygon.rn– Off-nadir angle of satellite image. – Error in classification.rnThe simulated images were generated from GCP polygons by transformation usingrncollinearity equation. Center of gravity as ICP were also calculated the simulated polygonrnimage. The results showed shape of polygon and off-nadir angle influence to accuracy of ICP.rnRequired accuracy were satisfied under the condition that “off-nadir angle” ranges from 0°torn10°and “flat area”.