step of the calculation is to transform the measured picture co-ordinates from
the comparator to the image co-ordinate system defined by the fiducial marks.
These transformations had the standard errors of unit weight 63, 64 and 65
¡urn for camera 1, and Jrl, 12 and 18 jum for camera 2. These values differ highly
significantly from what is to be expected from the information in chapter 8.2.3
Systematic changes in the positions of the fiducial marks in both cameras have
occurred after the determination of their co-ordinates.
Also the scale factors of the transformations indicate systematic disturbances
of the fiducial marks. The following results were obtained:
Testing the variance of the scale between pictures against the variance wit
hin, we find that the difference is not significant, and thus the scale can be assu
med constant. But the scale of the pictures from camera 2 differs highly signi
ficantly from scale factor = 1. Further, the standard errors of unit weight of
each camera are very close to each other which indicates that
(df)-s\/o 2 8.2.1
is not ^-distributed.
The conclusion is that the co-ordinates of the fiducial marks of both cameras
used in these calculations were in error. The marks must have changed their
locations between the operations.
It is possible that the film causes these effects but we cannot test that by
these measurements. However, the same sort of film has been used in all cases
and the photographic treatment has been standardized, which makes it rather
unlikely that film deformations cause the discussed phenomenon.
There are two possibilities in the following computations. First, the fiducial
co-ordinates determined in chapter 8.2.3 can be used and the standard errors of
unit weight of the transformations will still be large. Second, the last measured
and transformed fiducial co-ordinates can be used instead of the first set and
the standard errors of unit weight will be smaller. Here the first possibility is
chosen.
8.2.5. Single Point Resection in Space
The following parameters have been included in the adjustment:
Exterior orientation elements XqY 0 Z 0 w cp x
Interior orientation elements yo c a$ a$
These are defined as in chapter 5.
The observations are assumed to be independent, and to have equal weights,
unity. Three pairs of pictures were taken, and the standard errors of unit weight
in the six adjustments were found to be 6.3 jum, 8.2 jum, 10.5 jum, 8.9 fxm, 6.9 jim
(see formulas 8.3.1 and 8.3.2)
50