%0 Journal Article
%T Augmented Reality to Support On-Field Post-Impact Maintenance Operations on Thin Structures
%A Luca De Marchi
%A Alessandro Ceruti
%A Alessandro Marzani
%A Alfredo Liverani
%J Journal of Sensors
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/619570
%X This paper proposes an augmented reality (AR) strategy in which a Lamb waves based impact detection methodology dynamically interacts with a head portable visualization device allowing the inspector to see the estimated impact position (with its uncertainty) and impact energy directly on the plate-like structure. The impact detection methodology uses a network of piezosensors bonded on the structure to be monitored and a signal processing algorithm (the Warped Frequency Transform) able to compensate for dispersion the acquired waveforms. The compensated waveforms yield to a robust estimation of Lamb waves difference in distance of propagation (DDOP), used to feed hyperbolic algorithms for impact location determination, and allow an estimation of the uncertainty of the impact positioning as well as of the impact energy. The outputs of the impact methodology are passed to a visualization technology that yielding their representation in Augmented Reality (AR) is meant to support the inspector during the on-field inspection/diagnosis as well as the maintenance operations. The inspector, in fact, can see interactively in real time the impact data directly on the surface of the structure. To validate the proposed approach, tests on an aluminum plate are presented. Results confirm the feasibility of the method and its exploitability in maintenance practice. 1. Introduction Augmented reality (AR) is a live, direct or indirect, view of a physical, real-world environment whose elements are augmented (or supplemented) by computer-generated input such as sound, graphics, images, or video data. AR was first used for military, industrial, and medical applications, but it was soon applied to numerous commercial and entertainment areas [1]. Numerous studies, developments and applications of AR have been proposed, as reported in the surveys by Azuma [2], Azuma et al. [3], Krevelen and Poleman [4], and Wang et al. [5], and modern trends on AR can be found in some very recent papers [6¨C8]. However, to the best of the authorsĄŻ knowledge, AR has been scarcely used in nondestructive testing and structural health monitoring (NDT/SHM) applications, probably due to the required multidisciplinary expertises including but not limited to solid mechanics, numerical simulation, signal processing, and data visualization. The idea to harness AR for developing, supporting and improving NDT/SHM is an innovative topic which should be better addressed by the literature. The use of augmented reality (AR), in fact, could boost the usability of some NDT/SHM applications in both technical and
%U http://www.hindawi.com/journals/js/2013/619570/