THIMRAN: A MATLAB toolbox for thermal image processing aimed at damage recognition in large bodies

THIMRAN (THermal Images Mosaicking, Registration and ANalysis) is a new MATLAB toolbox proposed for processing data provided by infrared thermography (IRT). The toolbox is able to perform a contactless recognition of damage of a large body like a masonry/concrete wall or a rock cliff, leading to useful information for health state evaluation and/or hazard assessment. In an IRT measurement session, series of thermal images are acquired throughout one or more heating/cooling diurnal cycles. The proposed approach relies on evaluation of the time history of the thermal contrast related to one or more thermal transients. This is an extension to large bodies of a method currently used in laboratory non-destructive testing. The toolbox contains all the necessary functions for a complete IRT-based evaluation of a large body: (i) preliminary image processing (mosaicking, or stitching, and registration); (ii) computation of thermal contrast for each image; (iii) damage recognition by means of pixel-by-pixel comparison of thermal images registered into the same reference frame. The toolbox is available as Supplemental data of this paper. The results of its application of to two case studies, i.e. a leaning bell tower and a rock cliff, are also described.