There are 75 parameters, which usually are unknown.
- The (N,E,H) coordinate values of 15 terrain points
(45 parameters)
= The 6 orientation parameters for each of the 5
photographs (30 parameters)
In order to determine these 75 parameters from the 60
observation equations, ground control points are
necessary. Assume we have given the ground control
coordinates of the first 6 terrain points. This should
allow us in principle to perform 2 space resections of the
first and second photograph and will establish an absolute
coordinate geometry in these photographs. Once the
systematic image deformation and the coordinate geometry
is reestablished in, say, the first photograph, the
absolute image coordinates for the other photographs can
be computed from the difference equations (3).
However, we cannot resect the first photographs with 6
control points only, otherwise we would get an
undetermined solution. The task we are given here is the
task of a full camera calibration in space. The strip
computation may be regarded as a combined camera
calibration/strip adjustment exercise, using a proper
control distribution.
98