Ground Penetrating Radar for Investigating Painted Walls and Floors of Ancient Buildings

Abstract

In this paper the Authors report performances, application, and case studies of two different ground penetrating radars specifically designed for Cultural heritage investigations. The first radar has been designed for investigating painted walls. It operates without contact (up to 3 m of distance), it transmits 4 GHz bandwidth (that means a theoretical resolution of about 2 cm) and its mechanical positioner is able to scan a surface 1.4 m wide and 1.9 m high. The aim of this radar is to gather information about the shallow layers (the plaster structure and possible plaster voids affecting the stability of paintings) up to 0.5 m depth. The second radar operates in contact with the floor. It has 900 MHz bandwidth, and it is able to penetrate up to several meters in a structure that consists of masonry walls/floors and void spaces. Its aim is to detect girders, vaults cavities, and other buried structures like tombs or crypts. Both the sensors have been used for investigating the world-famous Great Hall (named also “Hall of five hundred”) in “Palazzo Vecchio”, the city hall of Florence, Italy. These radar sensors have provided valuable clues and factual elements for reconstructing the structure of the hall in the centuries, that is a question often disputed by the scholars.