3D Modeling applications for cultural heritage

The arising interest towards 3D modeling of both single objects and whole environments is strictly related with the availability of more and more powerful computing and surveying devices. A new set of issues has to be addressed in the 3D modeling of real objects. A lot of data are needed about the object surface or volume, which have then to be aggregated, regardless the data format and the acquisition device used, in order to get the final model. Actually, the data registration step requires the estimate of a first approximate estimate of the alignement between acquired data. This approach is often time-consuming, increases the final cost of the 3D model and represents the major limit to the wide spreading of real object models. Taking into account this drawback, a fully automatic range data registration system has been developed. This system is able to execute all the steps needed for 3D modeling of real objects in automatic way or at least minimizing as more as possible the human intervention, without any other information but the range data only. In this paper an overview of the whole registration system is presented, focusing on the integration between the two main blocks. In the first one, overlapping areas between range image pairs are detected by mean of spin-images and an initial approximate alignement between image pairs is computed. Then, in the second block, a refinement of this estimate is performed by use of a cascade of two registration algorithms: the Frequency Domain and the ICP. Some interesting applications of proposed strategy for 3D modeling of cultural heritage objects will be also reported.