Comparison of Terrestrial Laser Scanners in production of DEMs for Cetara Tower

The main goal of this work is to study and experiment the use of the terrestrial laser scanning technique in order to survey an architectural heritage; we try to estimate both the precision and the accuracy of the results, and to supply a methodology for the treatment of the acquired data. The experiment concerns the survey and the modeling of a tower characterized by a very articulated plan and a complex geometry placed in Cetara (Amalfitan Coast). We use five different laser scanning instruments, both at medium and long range. In order to estimate the laser sensor performances with respect to two main parameters, the range and the accuracy, we carried out a number of scanning at both different distances from the object and various resolutions. The surveys carried out with the different instruments demanded different design, planning and tests execution. Modeling has been carried out using several commercial software used to filter the scan results and to reconstruct both the nurbs which are part of the 3D model and the solid one by means of triangulation. In any phase of the work we try to compare a number of characteristics of the five laser sensors we used in order to define their performance and above all their suitability for surveying an architectural heritage such that we choose as Test. Before making the comparison, we aligned all data in order to transform them from the local reference systems to a common one.