Combining Laser Scanning and Photogrammetry - A Hybrid Approach for Heritage Documentation

Abstract

High quality 3D models of cultural heritage sites can be generated efficiently by laser scanning, which allows the accurate and dense measurement of surface geometry. In addition to the geometric data collection, texture mapping based on additionally collected digital imagery is particular important for this type of application. This requires a combined processing of range and image data sets. For this purpose, they have to be registered or aligned by a suitable transformation to a common reference coordinate system. The involved transformation parameters can be determined based on corresponding elements to be extracted from the different data sets. In the paper an efficient edge detection algorithm is presented, which allows for the automatic segmentation of such primitives even in complex scenes. In order to achieve a high quality 3D photo-realistic mode,l this alignment process has to be followed by an automatic texture mapping, which is discussed in the second part of the paper. The presented algorithms are demonstrated in the framework of a project aiming at the generation of a 3D virtual model of the Al-Khasneh, a well-known monument in Petra, and a Roman Theatre in ancient Jerash city, Jordan.