Ortho-Photo Mosaik from Lake Batu, north of Palangka Raya near river Kahayan, 9-2010 (acquired 7.8.2007)
Figure: Ortho-Photo-Mosaik from Kahayan river and Lake Batu
by Viktor Boehm and Alvand Miraliakbari
The area along river Kahayan and Lake Batu north of Palangka Raya was scanned with a LiDAR and a Hasselblad Camera 12 times with an overlap of approx. 50% in an average altitude of 500m on the 7. August 2007. The weather was good. Beside LiDAR data RGB-Photos were taken with a Hasselblad camera of 22MB image size (5440 x 4080). These RGB-Photos had in flight direction and to the side an overlap. For the 3.4km wide and 6.5km long area we collected more than 300 RGB-Photos.
The orientation parameters (x, y, z, flight altitude, tilt angles, time, camera boresight) were stored during the helicopter flight. They were first used to ortho-rectify the RGB-Photos.
Some misalignments over the images were noticed. An automatic aerial triangulation process was used to generate an Ortho-Photo Mosaik. Next step was the Ground Control Point (GCP) measurements which were taken in the LiDAR data. This was carried out with the multi photo measurement tool. Most of those GCPs were found along road intersections since they are easy to find. The final Ortho-Photo-Mosaik from Kahayan river with lake Batu has a size of 3.4km x 6.5km with approx. 9000 x 17000 pixels (pixel resolution 0.2m x 0.2m). The Ortho-map above has a 5x reduced resolution!!! 14.9.2010