3D modeling of close-range objects: Photogrammetry or Laser Scanning ?

Photogrammetry deals since many years with the 3D reconstruction of objects from one or more images. It provides for accurate sensor calibration and object modeling using analog or digital imageries, it is very portable and many commercial software is available for image processing and 3D modeling. On the other hand, laser scanning technology and all the related reverse engineering software are becoming a very promising alternative for many kind of surveying and modeling applications. Laser scanners allow to acquire very quickly a huge amount of 3D data which can be often combined with color high-resolution digital images. Among the plenty of works so far presented, in particular on the use of laser scanning for cultural heritage survey, some modeling and accuracy related issues have been not yet solved and discussed in details. In this contribution we report about two case studies realized with photogrammetry and laser scanner and we provide some advices and suggestions about the more suitable 3D modeling method for a given object, taking into account its size and shape complexity, the required accuracy and the target application.