What is HDR (High Dynamic Range)

The study of the shape in the architectural survey is the principal goal of the surveyor. Any shape is based on stringent geometric rules that the current digital methods of data acquisition don't detect directly. The basic element in the integrated digital survey is today the point that must to be processed, automatically or manually, to generate a 3D mathematic model. In this chapter the author wants to highlight how these data are important not only for metric information but also to characterize the quality of the shape through the digital photographic techniques. The description of some practical examples proves that in both phases of the survey, acquisition and processing, it is important to know the relations between the shape of the object and the instrumental characteristics in the different methods.