This paper presents an automatic procedure for the geometric corrections of very-high resolution (VHR) optical panchromatic satellite images. The procedure is composed of three steps: an automatic ground control point (GCP) extraction algorithm that matches the linear features that were extracted from the satellite image and reference data; a geometric model that applies a rational function model; and, the orthorectification procedure. Accurate geometric corrections can only be achieved if GCPs are employed to precisely correct the geometric biases of images. Due to the high resolution and the varied acquisition geometry of images, we propose a fast, segmentation based method for feature extraction. The research focuses on densely populated urban areas, which are very challenging in terms of feature extraction and matching. The proposed algorithm is capable of achieving results with a planar accuracy of approximately one pixel or better, on a test set of 14 panchromatic Pléiades images. The procedure is robust and it performs well in urban areas, even for images with high off-nadir angles.
COBISS.SI-ID: 44575277
In the paper I presented the developed automatic procedure for generation of true orthoimages from very high-resolution satellite images. True orthoimages are an improved version of traditional orthoimages as they are adjusted also for high objects (e.g. high buildings). The automatic workflow encompasses various modules, starting from the extraction of ground control points, through the geometric processing of image blocks, orthorectification and finally generation of true orthoimages. The orthorectification procedure uses a high-resolution digital surface model derived from laser scanning data. The paper presents the results of the geometric correction and the creation of true orthoimages that can be used directly by end-users.
COBISS.SI-ID: 45446445
In the monography we presented various geometric models and types of orthorectification and described a fully automated procedure for orthorectification of optical satellite images that was developed. The resulting orthorectified image is in the national coordinate system and constitutes a suitable source for spatial analyses. The original procedure connects several different methods into a single, robust system for automatic generation of orthoimages. The scientific monography describes the whole automatic orthorectification process, which comprises four basic modules: module for extracting and preparing the metadata, module for automatic extraction of ground control points, module for calculation of parameters of the geometric model, and module for orthorectification. Experiments and results with RapidEye and WorldView-2 images are also presented. The experiments evaluate the procedure for automatic extraction of points, the physical geometric model, the elimination of gross errors, and the positional accuracy of the orthoimages. The results indicate that the automated procedure produces orthoimages with a positional accuracy of about two pixels or better, even if several gross errors are present among the automatically extracted ground control points.
COBISS.SI-ID: 292901120