Alessandro Spinetti

An ultra-wideband high-dynamic range GPR for detecting buried people after collapse of buildings

An ultra wide band high dynamic range GPR radar - has been tested for buried victims detection. After a building collapse, for example due to an earthquake, the priority of search and rescue teams is to localize people trapped under debris. Several tools are available to help the detection of buried humans, such as micro-cameras, high sensitivity microphones, and so on. Many of these tools present some limitations such as low penetration depth and high susceptibility to external noises. In this paper the authors test the use of an Enhanced Ultra Wide Band (UWB), Continuous Wave Stepped Frequency (CW-SF) Ground penetrating radar as rescue equipment. The radar has been experimented both in controlled environment, and in a real test site, at the Fire-fighters Station of Pisa, Italy.

Range sensors on marble surfaces: quantitative evaluation of artifacts

While 3D imaging systems are widely available and used, clear statements about the possible influence of material properties over the acquired geometrical data are still rather few. In particular a material very often used in Cultural Heritage is marble, known to give geometrical errors with range sensor technologies and whose entity reported in the literature seems to vary considerably in the different works. In this article a deep investigation with different types of active range sensors used on four types of marble surfaces, has been performed. Two triangulation-based active sensors employing laser stripe and white light pattern projection respectively, and one PW-TOF laser scanner have been used in the experimentation. The analysis gave rather different results for the two categories of instruments. A negligible light penetration came out from the triangulation-based equipment (below 50 microns with the laser stripe and even less with the pattern projection device), while with the TOF system this came out to be two orders of magnitude larger, quantitatively evidencing a source of systematic errors that any surveyor engaged in 3D scanning of Cultural Heritage sites and objects should take into account and correct.

Digital Three-Dimensional Modelling of Donatello's David by Frequency-Modulated Laser Radar

Abstract In this paper a laser scanner based on the operation principle of continuous-wave frequency-modulated (CWFM) radar is applied to the acquisition of a digital three-dimensional model of the well-known David by Donatello. The steps of the acquisition procedure and the related technical solutions are reported. The scientific focus was on the processing pipeline simplification due to the new acquisition methodology. Detailed results are presented, demonstrating how the use of this type of sensor allows digitization of works of art made of materials that cannot be sampled, and improvement in the overall level of modelling accuracy.

A reconfigurable stepped frequency GPR (GPR-R)

Ground Penetrating Radars are a unique and well known tool for soil investigation.

ORFEUS GPR: a very large bandwidth and high dynamic range CWSF radar

A very large bandwidth and high dynamic range Continuous Wave Step Frequency (CWSF) Ground Penetrating Radar (GPR) has been developed with the aim to increase the detection capabilities with respect to current systems . In order to achieve this goal, an innovative electronic equipment have been designed and developed. This radar operates with ultra wide bandwidth, ultra fast scan and very high dynamic range capabilities.

A reconfigurable stepped frequency GPR (GPR-R): The antenna subsystem

GPR-R technology fully exploits the unique advantages of the stepped frequency radar technique. A GPR equipment based on this technology has been recently developed by the authors: it is able to reconfigure its integration time and transmitted power vs. frequency in order to increase penetration capability and radiofrequency interference immunity. This paper describes the antenna subsystem of this radar.