Orthorectification of KOMPSAT Optical Images Using Various Ground Reference Data and Accuracy Assessment

Abstract

Along with the appearance of high resolution satellite images, image correction using Rational Polynomial Coefficients (RPCs) has become common. Location accuracy of Korea Multipurpose Satellite (KOMPSAT) standard images is still not adequate, so, in order to leverage the KOMPSAT images for applications such as mapping and change detection, it is necessary to orthorectify the images. In this study, using updated RPCs, we performed orthorectification of KOMPSAT-2, KOMPSAT-3, and KOMPSAT-3A images using various data. Through this study, we discovered that the orthorectification result using precise Ground Control Points (GCPs) and Digital Elevation Model (DEM) is the best, but it was found that the correction results through image matching are also excellent. In particular, it was confirmed that orthoimages with a planimetric accuracy around 3 m (Root Mean Square Error (RMSE)) can be generated by using well-known matching algorithms with open data such as OpenStreetMap (OSM) and Shuttle Radar Topography Mission (SRTM) DEM, which can be acquired by anyone. Although the accuracy was low in some mountainous terrain, it was confirmed that it could be used for generating KOMPSAT orthoimages using open data. This paper describes the results for orthorectifying high resolution KOMPSAT optical images using various reference data.

Updating Absolute Radiometric Characteristics for KOMPSAT-3 and KOMPSAT-3A Multispectral Imaging Sensors Using Well-Characterized Pseudo-Invariant Tarps and Microtops II

“…In this study, we officially updated the DN to radiance coefficients for KOMPSAT-3 and -3A to ensure that accurate and quantitative images are available for practical use, as the imaging sensor needs to be calibrated both geometrically and radiometrically [27,28]. Because the accuracy of radiometric calibration ultimately influences all relevant fields utilized by KOMPSAT-3 and -3A, it is essential to determine the variations of KOMPSAT-3 and -3A due to TDI adjustments and sensor degradation over time.…”

“…Therefore, the coefficients should also be adjusted by performing a new vicarious calibration for consistent radiance values. Although most studies related to these satellites have focused on the verification and calibration of the imaging sensors [23][24][25][26][27][28][29][30], efforts to improve and conserve the quality of satellite images must be maintained. Therefore, this study performs an absolute radiometric calibration of KOMPSAT-3 and -3A multispectral images from electro-optical imaging sensors to obtain the latest DN to radiance coefficients.…”

Quality Assessment of Four DEMs Generated Using In-Track KOMPSAT-3 Stereo Images

“…The accuracy of DEMs generated using stereo images is largely dependent on two factors [4], the first of which is the accuracy of the sensor modeling. Typically, the bundle adjustment method of rational function models (RFMs) is used to establish the relationship between a satellite's image coordinates and the ground coordinates [5]. Second, DEM accuracy depends on the stability of the stereo geometry.…”