Analysis of Rational Function Dependency to the Height Distribution of Ground Control Points in Geometric Correction of Aerial and Satellite Images

One of the existence mathematical models is Direct Linear Transformation (DLT). These equations are being regarded because of their simplicity as they are direct. When the height distribution of ground control points (GCPs) is inappropriate, height accuracy of DLT is low. This problem was not obvious about rational functions. To assess this case, the accuracy of rational functions has been tested in three different cases of GCPs distribution including over sampling, optimum sampling and under sampling. At last we have come to conclusions that the accuracy of rational functions in over sampling and optimum sampling are more than under sampling. But the accuracy of over sampling has not a significant difference with the accuracy of optimum sampling. In all cases, to compare the direct and indirect solution of rational function, we solved rational functions with both mentioned methods. At last it was clear that the accuracy of direct solution is more than the accuracy of indirect solution. All done tests are in terrain-dependent case of rational functions.