Ortho-Photo Generation and Mosaiking of City Palangka Raya, 5-2009 (acquired 10.8.2007)
by Viktor Boehm and Alvand Miraliakbari
The city Palangka Raya was scanned with a LiDAR and a Hasselblad Camera 18 times with an overlap of approx. 50% in an average altitude of 500m on the 10. 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 5km wide and 7km long area of Palangka Raya we collected more than 400 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 city Palangka Raya has a size of 5km x 7km with approx. 25000 x 35000 pixels (pixel resolution 0.2m x 0.2m). The city map above has a reduced resolution!!! 29.5.2009