inbul 2004
VGO30 AT
ated Sensor
it calibration
CE
| via a RS232
ulse and the
rovides the
r the forward
th the photo
osition, track
from mission
int number).
:dback signal
'amera at the
e and is sent
i is recorded
AEROcontrol
ntation of the
dback signal,
. The display
pilot or the
sor system by
ACAMp SU
crewed on an
to the main
F and durable
Mp.
rocessing
FRACM p are
WinMP, so
open (tracks)
he GPS/IMU
ously marked
ant data from
n are stored
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part Bl. Istanbul 2004
together with the image data by the ULTRACAM| inflight
>
software.
5. PROCESSING OF DIGITAL IMAGES WITH
GPS/IMU DATA
The traditional photogrammetric workflow is based on 60%
forward overlaps. Therefore a stereo operation employs two
intersecting projection rays without sufficient redundancy. The
use of digital sensors can change this by increasing the number
of images without increasing the project costs, as long as
processing is automated. This encourages thinking about the
use of higher than 60% forward overlaps.
The benefit of high overlaps is obvious. Each terrain position
is mapped. more than twice, redundancy is available and
blunders and mismatches can be detected automatically.
So the aero-triangulation will become more robust and DEMs
will also be without mismatches and all terrain segments will
have coverage. An integrated system with geo-positioning tools
and multi-ray photogrammetric processing will result in a
DEM-robot and will also produce true orthophotos without
human interaction.
5.1 Direct Georeferencing (DG) and Integrated Sensor
Orientation (ISO)
The use of directly measured EO-parameters in
photogrammetric data processing can generally be
distinguished in two different concepts:
The use of directly measured image EO-parameters for
photogrammetric data processing without conducting an AT
over the entire image block presents the principle of DG. On
the other hand, the simultaneous processing of GPS/IMU data
and image information for the determination of the EO-
parameters in an extended aerial triangulation is referred to as
Integrated Sensor Orientation (ISO) [Heipke 2001].
Which approach is suitable for a specific task depends on many
factors, e.g. the required accuracy, the image scale, the
availability of ground control information. In general, DG is
used for medium to small scale projects, while ISO is applied
to large and medium scales [Kremer 2002, Kremer & Kruck
2003].
In a completely digital workflow, the range of projects where
ISO is the method of choice might become larger compared to
the projects where DG will be used. Because the images are
available in digital form anyway, the additional effort to
perform a GPS/IMU assisted automatic AT for the complete
block is quite small compared to the advantages of ISO
compared to DG.
6. FLIGHT MISSION *GRAZ"
On the 22"! of April 2004, a flight mission was done by near
Graz, Austria.
The system was installed in a Cessna 206 survey aircraft of
Bildflug Fischer, Klagenfurt, Austria.
The mission consists of a block of seven lines with two cross
strips. A forward overlap of 90%, a sideward overlap of 85%
and a flying height of 1400m above ground, resulting in ground
sample distance (GSD) of 0.12 m, was planned. The images
175
were triggered by the CCNS on the planned positions (an
automatic mode is possible, where the camera is only sending
the feedback pulse to the CCNS).
Fig. 4: Installation of the ULTRACAM) in the Cessna 206
survey aircraft
» HA pe AA CU SLR A ddr poda Bed epe mda n adde het
4
; i
RA uU ai e ebay pa iade. PUR
*
;
gm eos ade Me dede dtm tg d Re ote + .
pred (rent pb Ra i qu ARA RRE
à i
HERB FE EE rua po : :
T Speen pm passat pu tete true ange oll
1
4
* +
le ir le ptm ded tom rd Re — & :
f * FOE ap t
è 1
+ á
Aie M RR die d tt qu m xd. a... L i .
+ FRA Sp RE ER BE oa eg
4 ¥
+ »
+ ¥
:
dmm Bg ^ i
; + Bf eo A KE
Fig. 5: Missionplanning for the project “Graz” with WinMP
£4(2) 22-04-04_42: Trajectory [GPS] ei
al Slama] se =f sl sen mT all [EER or [710
Fig. 6: Recorded trajectory
