Laser Scanning and Photogrammetry: a Hybrid Approach for Heritage Documentation

The work described in this paper wants to underline the necessity to integrate the laser scanning technique and photogrammetry in order to improve the geometry and visual quality of the collected 3D model. Although the 3D model produced by laser scanning contains a large number of meshed triangles, it can still be difficult to localize important features like the edges and cracks on the monument surface. In our approach, information on edges and linear surface features is based on the analysis of the images. The segmentation of these images provides an intermediate result for the position of edges and linear surface features. The missing 3rd dimension of these details is extracted from the laser scanner data. The approach applies image based semi-automated techniques in order to bridge gaps in the laser scanner data and add new details, which are required to build more realistic perception of the scene volume. The potential of the algorithms is demonstrated within a project aiming at the generation of a 3D virtual model of the Al-Khasneh, a well-known monument in Petra, Jordan.