Generation of a GIS-based environment for infrared thermography analysis of buildings Mattia Previtali a , Silvia Erba a , Elisabetta Rosina a Veronica Redaelli b , Marco Scaioni c , Luigi Barazzetti a a Politecnico di Milano, Department of Building Environmental Science and Technology Piazza Leonardo da Vinci 32, Milan, Italy (mattia.previtali,silvia.erba)@mail.polimi.it,(elisabetta.rosina, luigi.barazzetti)@polimi.it b Università degli Studi di Milano, VESPA Department Via Celoria 10, Milan, Italy vereda@tin.it c Tongji University, Centre for Spatial Data Analysis and Sustainable Development Applications College of Surveying and Geo-Informatics 1239 Siping Road, 200092 Shanghai, P.R. China marco@tongji.edu.cn ABSTRACT Nowadays Infrared Thermography (IRT) is a fundamental tool for inspection of buildings and identification of anomalies. However, there is a lack of commercial software packages able to perform the analysis of differential temperature gradients. This paper presents an innovative GIS-based methodology aimed at speeding up recognition of thermal anomalies revealing finishing damages like detachments. In particular, the developed procedure can be applied to different raster products like thermographic mosaics, orthophotos, rectified images, etc. The major advantage is the possibility of doing thermal analysis on ‘thermographic orthophotos’, overlaying the metric content of traditional orthophotos but preserving the temperature registered during the IRT survey. To obtain ‘thermographic orthophotos’ a photogrammetric methodology aimed at mapping IR thermal images onto 3D models created with terrestrial laser scanning technology was developed. Once the IRT images are mapped, the textured digital model of the façade is used to generate an orthophoto and processed in a GIS environment to support new thermal analysis. The image processing pipeline will be illustrated starting from data generation up to visualization and management. Moreover, real case studies for on-going restoration projects will be illustrated and discussed. Keywords: Infrared thermography, GIS, photogrammetry, sensor fusion, texture mapping 1. INTRODUCTION Nowadays Infrared Thermography (IRT) is one the most used tool for the inspection of buildings. It is currently employed to identify thermal bridges, water infiltration, energy leaking from the building’s envelope, problems with the electrical and mechanical installations under serviceability conditions, etc.[1-2]. The scientific literature reports several papers showing the effective usage of IRT in building maintenance and conservation [3-5]. On the other hand, one of the well-known major limitations of IRT surveys is directly connected to the reduced angle of view of infrared (IR) sensors utilized in terrestrial applications. For localized degradation processes, the analysis of each single image can be sufficient for a complete identification and localization. However, in the case of large constructions or when the thermal abnormalities are evident only at a larger scale, a single image analysis may not be enough. To overcome this problem different thermal images can be mapped together on the analyzed building model. Obviously, the orientation of thermal images and the reconstruction of the geometric model of building have to be carried out in the same reference system. Infrared Remote Sensing and Instrumentation XX, edited by Marija Strojnik, Gonzalo Paez, Proc. of SPIE Vol. 8511, 85110U · © 2012 SPIE · CCC code: 0277-786X/12/$18 · doi: 10.1117/12.930050 Proc. of SPIE Vol. 8511 85110U-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 03/18/2013 Terms of Use: http://spiedl.org/terms