PHOTO-PLAN CREATION OF CYLINDRICAL OBJECTS
Keywords: Photo-plan, Unwrap able solid figure, Orthophoto, Single image photogrammetry, Orientation, Cylinder, Cone
Abstract. Photo-plans are frequent outputs in photogrammetry focused on historical planar objects. For planar spatially articulated objects it is not possible to create an exact photo-plan but is it possible to make an orthophoto. These above mentioned methods are inappropriate for cylindrical objects. In our contribution, methods of creating photo-plans are evaluated when used for cylindrical objects. This paper deals with today's possibilities, which are available for developable bodies. Commercial software dealing with these issues is introduced and some published procedures of creating photomaps using unwrapping are shown. There are specific given examples of processing and results. A number of historical buildings contain cylindrical elements – such as towers, vaults, and apses. Their documentation is not easy and it is problematic to use the classic single image photogrammetry and popular photo-plan, which contains all photographic details. It seems to be appropriate to unwrap this form into a plane. Subsequently, the paper presents main computational procedures and methods introduced in the Laboratory of Photogrammetry of the CTU in Prague. In the practical part of this paper the software Photo UnWrap and the methods used by authors for unwrapping cylindrical and conical bodies are introduced.