Automated Bias-Compensation Approach for Pushbroom Sensor Modeling Using Digital Elevation Model

Bias compensation of rational polynomial coefficients (RPCs) is one of the most important preprocessing steps in high-resolution satellite image processing. It generally requires accurate ground control points (GCPs), but GCP acquisition is both time consuming and laborious. In this paper, we propose a time-and cost-efficient method for automated bias compensation of the RPC of high-resolution stereo image pairs. Two Korean Multi-purpose Satellite-2 (KOMPSAT-2) stereo image pairs acquired in Daejeon and Busan, Korea, and the Shuttle Radar Topographic Mission (SRTM) digital elevation model (DEM) with the spatial resolution of 3 arcsec (similar to 90 m) were used for analysis. In the two study areas, 33 and 29 check points were respectively used for the performance evaluation. After bias compensation with the proposed method, the root-mean-square (RMS) errors for both of the study areas were less than 10 m, in all coordinate components, while the RMS error vectors were approximately 10 m. Although the RMS error vectors were slightly larger than the standard deviations of the residual errors of the initial ground coordinates, it would seem that they yielded acceptable values because the proposed method largely depends on the spatial resolution, the error of the SRTM DEM, the tie point selection error, and so on. Therefore, it can be concluded that the proposed method allows for the automated bias compensation of RPCs of KOMPSAT-2 images.