The first step is the selection of an appropriate
geometric correction model. According to the deformation characteristics
shown in Fig. 4, a quadratic polynomial model, which is
described by Eq. (3), was adopted to correct geometric deformation
of the TM image. Second, sets of 16 GCPs were selected using
different designs, namely SRS, SCS, and UKMS, were selected to
determine the coefficients of the regression model. Besides, 50 VPs
were selected by SSRS to assess the accuracy of geometric correction.
Third, we performed geometric correction using a quadratic
polynomial model with 16 GCPs and resampled the corrected image
employing the cubic convolution resampling. Finally, the accuracy
of geometric correction was assessed using the VPs.