City Modelling - eCAADe 29 99 Single Image Ambiguity and Adjustment of Cultural Heritage Modeling Approach Vesna Stojaković 1 , Bojan Tepavčević 2 1,2 University of Novi Sad, Faculty of Technical Sciences, Department of Architecture and Urbanism 1 vesna100jakovic@gmail.com, 2 tepavcevicb@yahoo.com Abstract. The objective of this research is to point out the deiciency of the modeling from a single image and give suggestion for the improvement. In the domain of cultural heritage visualization, single image modeling is mainly used to recover the scene shown in the historical photographs. In this paper, some common ambiguities in the area of the historical architectural environments are highlighted. In most approaches user is the one to introduce and choose constraints, and therefore he must have control over the ambiguity problems. We propose suggestions about how to adjust the single-image-based modeling in order to minimize chance for irregular 3D shapes to emerge due to ambiguity. Simple examples are used to illustrate how ambiguity of a single image can affect the models veridicality, which are the common mistakes that inexperienced user can make and how and when they can be corrected. Keywords. Single-image-based modeling; Restitution; Perspective; Photography; Shape ambiguity; Cultural heritage. INTRODUCTION Cultural development is relected in monuments, architecture and public spaces. Future genera- tions should know about the appearance of the destroyed and modiied human built environment as well as we need to reconstruct, conserve and re- vitalise the valuable historical background. Human environment is constantly being modiied. When- ever it is possible, cultural heritage should be saved or at least properly surveyed and documented (Waldhäusl, 1992). In order to survey cultural heritage structures, a selection of the appropriate technological approach is very important (El-Hakim, Beraldin and Pica, 2002). It has to be eicient, lexible, clear and easy to use (Stojaković and Tepavčević, 2009). If not, spatial in- formation about many objects could be lost. For cultural heritage digital documenting single-image-based modeling is very important. If just a single image is available for 3D shape recov- ery, which is common in cultural heritage archives, this is the optimal method to use (Stojaković and Tepavčević, 2011; Heuvel van den, 2001). In spite of that, software applications, in our opinion, are not organized in a way that suits the average user. There