2.1 Orientation
2.1.1 Interior orientation of digital image
This program is aimed at determining the transformation from scan-
ning coordinate system to photo-coordinate system in terms of four
or more fiducial marks and camera calibration data. In order to com-
pensate a slight rectangularity and skewing error in digitized images
a linear affine transformation should be adopted:
Xg=m() + m4x + moy
Yg=N) + N4X + N2Y
in which my ms I, , no» n,» n,denote independent parameters of
affine transformation. One example of interior orientation is shown
in table 1. As can been seen from the table, the different scaling
errors in x- and y-direction are more significant than the skewing
error, which indicates that the perpendicularity of scanning line
to stepping direction is very accurate.
Table 1. Parameters of Interior Orientation
Yarameters Left Image Right Image
m0 m, m, 2141.51 | 1.00506 | -0.00246|2147.42|1.00289| -0.0059T
ng D4 n, 2157.11.31 0.00257 1.001735|2155.52|0.00410| 1.00162
2.1.2 Relative and Absolute orientation
vonsidering the results of relative and absolute orientation di-
rived from two-dimensional digital correlation is less accurate,
the elements of orientation computed from aerial triangulation have
been used for SODAaMS directly.
2.1.5 Computation of parameters for correcting model's deformation
Although tne distortions in digitized images have been taken into
acount, the residuals have still effected deformation of stereo-
moael. From the results of experiments for four mocels listed in
table 2, it has clear shown that correction for terrain model's
deformation is essential to increase the accuracy of digital image
correlation.
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