Page 3 of 3 Previous In commercially available digital photogrammetric software, object extraction functionality is restricted to manual or semi-automated measurements together with the capability of attribute data acquisition. The main applications are 3D modeling of city and industrial areas. Commercial systems assist the human operator in measuring 3D objects in combination with registration of attribute data in a semi-automated mode, e.g. Leica Photogrammetry Suite, Z/I Image Station or Virtuozo IGS Digitize. These systems provide libraries containing objects, e.g. buildings or streets, which allow for object modeling according to certain rules concerning object topology. However, there is no functionality available that would consider the specific requirements of cultural heritage modeling. For the 3D modeling of buildings and other man-made objects we have developed and tested a methodology called CyberCity Modeler (CC-Modeler). This is a semi-automated technique, where the operator measures manually in the stereomodel a weakly structured pointcloud, which describes the key points of an object. The software then turns this pointcloud automatically into a structured 3D model, which is compatible with CAD, visualization and GIS software. Texture can be added to the geometry to generate a hybrid model. A DTM can also be integrated. An example using CyberCity Modeler for 3D modeling of terrain and buildings in an archaeological application was conducted for the pre-hispanic site of Xochicalco, Mexico, where an urban center was reconstructed photogrammetrically from aerial images (Gruen and Wang, 2002), see Fig. 2.  Figure 2: Partially textured 3D model of Xochicalco, derived semi-automatically from a stereopair of aerial images using CyberCity Modeler 6. A remotely controlled model helicopter over Pinchango Alto, Peru Model helicopters belong to the class of UAVs (Unmanned Autonomous Vehicles). These vehicles are used in a great variety of applications. Lately we have applied such a system to Cultural Heritage modeling. In the vicinity of Palpa, the prehispanic site of Pinchango Alto is an attractive, yet difficult target for archaeological research. On the one hand, its stone architecture, abundant surface finds, and richly furnished graves dating to the Late Intermediate Period (AD 1000-1400) offer many opportunities to study this still poorly understood pre-Inkaic period. On the other hand, access to and working on the site is rather difficult. The recording of the preserved surface remains therefore requires a highly mobile and flexible documentation system. In a 2004 field campaign we used a model helicopter carrying a CMOS camera to acquire a series of vertical aerial images for photogrammetric recording and 3D modeling of the site and the surrounding terrain. The system used in Pinchango Alto is based on a commercial low cost model helicopter. It features an integrated GPS/INS based stabilizer. While the GPS/INS unit enables semi-automated navigation along a predefined flight path, the stabilizer ensures a stable flight attitude and thus highly reliable image acquisition. The processing and analysis of the acquired images encompassed image pre-processing, semi-automatic triangulation and automated DTM generation. A 3D model of the site was produced and visualized. The results were analyzed concerning in particular the potential of DSM generation from model helicopter images as compared to terrestrial laserscan data. For details of the whole mission (data acquisition and processing) see Eisenbeiss et al., 2005. Figure 3 shows the model helicopter in action over Pinchango Alto and the userinterface of the remote control system.  Figure 3: Left: Model helicopter over Pinchango Alto Right: User interface showing the flightplan and the control panel  Figure 4: Left: Pinchango Alto (marked with red box) in an aerial image of 1997 (1:7000) Right: Snapshot of a virtual flight over the hybrid model, generated automatically from helicopter images 7. 3D reconstruction of adobe architecture at Tucume, Peru In recent years we have modeled a number of large Natural and Cultural Heritage sites, e.g. Mount Everest (Gruen and Murai, 2002), Ayers Rock/Australia, Xochicalco/Mexico (Gruen and Wang, 2002), Geoglyphs of Nasca/Peru (Lambers and Gruen, 2003, Lambers and Sauerbier, 2003, Lambers et al., 2004), Pinchango/Peru (see previous section and Eisenbeiss et al., 2005) and Bamiyan/Afghanistan (Gruen et al., 2004a,b, 2005). Currently we work on Machu Picchu/Peru. In the region of Túcume in northern Peru, nearby the cities of Chiclayo and Trujillo, the so-called “Pyramids of Túcume” represent a unique example of adobe architecture built during different periods of pre-hispanic cultures. About 3000 years ago, people started to construct various buildings until they were completed during the 13th century A.D. in the period of Sicán, and later also used by the Incas. From the Cerro La Raya, a characteristic hill in the centre of the site, 26 adobe buildings are visible, the largest one, Huaca Larga, with a length of 545m, 110m in width and 21m in height. On top of Huaca Larga, the Incas constructed a stone building. During excavations in the last years, tombs, reliefs and coloured wall drawings were found. Besides the pyramids, the complex contains platforms, citadels, residential areas and cemeteries. The fact that Túcume has been an urban settlement area for the cultures of Lambayeque, Chimú and Inca consecutively makes it one of the most important Cultural Heritage sites of the ancient Peru. As the adobe structures are heavily affected by wind erosion, the architecture should be modelled as well as possible in an unaffected state. For this reason, aerial imagery from the years 1949 and 1983 were acquired from the Peruvian SAN (Servicio Aerofotográfico Nacional, Lima), which show the adobe complex in two different states. As no control points existed for the 1949 images, two maps and the 1983 imagery had to be used for the orientation. The orientation of the 1983 images was accomplished on an analytical plotter WILD S9, while for the orientation of the 1949 images both, the analytical plotter and a digital photogrammetric workstation Virtuozo 3.1, were used. The photogrammetric products derived from the oriented 1949 images are a manually measured DTM, an automatically generated DSM, an orthomosaic and a photorealistic 3D model. The hybrid model was visualized with the software packages Skyline Terra Builder / Explorer Pro and ERDAS Imagine Virtual GIS (see Figure 5). The 3D model can now serve archaeologists and other scientists as a means for documentation, analysis and presentation of the Cultural Heritage site of Túcume in a state of preservation as of 1949.  Figure 5: View onto the 3D model of the Tucume adobe complex, produced with Skyline Terra Explorer Pro. Overlaid is the texture from the 1949 aerial images. To the left is Huaca Larga, a huge adobe building of 545 m length, with an Inka stone building on top. 8. Conclusions We have shown here how highresolution satellite images, aerial and terrestrial images can be used in order to generate hybrid 3D models for archaeological and Cultural Heritage applications with photogrammetric techniques. The digital nature of many of those images and the progress in automatic photogrammetric processing allows for very efficient procedures and for new kinds of results. Additional options for recording and processing are available through the use of aerial and terrestrial laserscanners, panoramic cameras and combined systems. Of particular interest is a UAV (Unmanned Aerial Vehicle) - a model helicopter, which works in an autonomous mode, based on integrated GPS/INS, stabilizer platform and digital cameras, and which can be used to get images from otherwise hardly accessable areas. This system, together with advanced software for automated processing will allow us in the near future to generate at least an initial model of the object fully automatically on-line in the field or immediately after data collection in the campaign office. All these presented technologies, together with Spatial Information Systems, 3D modeling, visualization and animation software are still in a dynamic state of development, with even better application prospects for the near future. Acknowledgements I would like to thank my cooperators H. Eisenbeiss, M. Sauerbier and Zhang Li for their very valuable contributions to this paper.
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