Towards automatic modeling of monuments and towers

Three-dimensional modeling from images, when carried out entirely by a human, can be time consuming and impractical for large-scale projects. On the other hand, full automation may be unachievable or not accurate enough for many applications such as culture heritage documentation. In addition, three-dimensional modeling from images, particularly fully automated methods, requires the extraction of features, such as corners, and needs them to appear in multiple images. However, in practical situations those features are not always available, sometimes not even in a single image, due to occlusions or lack of texture on the surface. Taking closely separated images or optimally designing view locations can preclude some occlusions. However, taking such images is often not practical and we are left with small number of images that do not properly cover every surface or corner. The approach presented in this paper uses both interactive and automatic techniques, each where it is best suited, to accurately and completely model monuments and towers. It particularly focuses on automating the construction of unmarked surfaces such as columns, arches, and blocks from minimum available clues. It also extracts the occluded or invisible corners from existing ones. Many examples, such as Arc de Triomphe in Paris, Florence´s St. John baptistery at Santa Maria del Fiori Cathedral, and other monuments and towers from around the world are completely modeled from a small number of images taken by tourists.