from
on has
ly the
larger
s have
dinate
ffered
urious
-photo
Best results have been obtained from the locally applied
bilinear correction. This is not surprising since the method
is both local and specific to each frame, providing the best
estimate of the actual image deformations occurring.
Unfortunately the method is also the most measurement
intensive, each complete set of reseau cross images for
every frame included in the bundle having to be measured.
The radial and tangential parameters estimated by each
adjustment were also significantly different within this set,
implying that the parameters were also modelling some of
the uncorrected film deformation. Again the image
deformations have had little effect on the estimated object
coordinates because the object space is highly constrained
by the convergent network.
3.3.2. Results from the twin photograph adjustments
with the Hasselblad camera.
All adjustments based on two photos have demonstrated
that higher object coordinate precision requires localised
correction provided by individual reseau measurement.
Non local correction of image deformation may be ignored
with this camera. This is especially true where scale
corrections based on fiducials are concerned since large
deformations, due to unflatness and tension at the format
edges, can contribute disproportionately. The raw
photo-coordinates have provided reasonable results with
a minimum of both computational and measurement
effort.
Hasselblad 2-Phorto
Full Control Partial Control
4 Raw Plate 4 à
* +
QM eee
+ + + + + *
S dibus irat | en |
| A + + + |. * + + .
pére tan
fA] 7 lu
X 4 +
i um 10 um
4 Local Blllnear
xx , ; ; = 4*1 * : +
* ata x * : | TR 4 : + | +
Î ot s + I A odes +
+ +
pr ed #
: ^41 i
f | #4] Me
+ + x + +
n. on
Figure 6. Some image coordinate residuals from the
stereopair Hasselblad surveys.
0b Ject Space Discrepancies
Front View
Affine Local BllInear
EN EN pe any
d dore rd
My TUN eue
/
AER M id
Top View
Row Plate Affine
AY MAT fe
Mean Bllinear
Local Billnear
M? nw
1 X puis
Figure 7. Object space discrepancies for the twin photo
Hasselblad survey using datum 1.
0b Ject Space Discrepancies
Front View
N Aff Ine Local BilInear
3 / / N E / à nd 7
foi | E
yrs / V, sb fif
/ ^A + \ | À > = ] 4
wl TN rl
f BV P spa E 7
) > x 1 Y e -
ri mm
J View
Raw Plate Affine
E Mean BllInear Local Bl/Inear
NN A = >
Figure 8. Object space discrepancies for the stereopair
Hasselblad Survey using datum 2.