Infrared thermography (IT) is a safe non-destructive testing (NDT) technique that has a fast inspection rate and is generally contactless. It is used for diagnostics and monitoring in several fields such as electrical components [2], thermal comfort [3], buildings [4], artworks [5], medical [6], security [7] and composite materials [8]. IT popularity has grown in the recent years due to spatial resolution and acquisition rate improvements of infrared cameras which have become more affordable. Another factor is the development of advanced image processing techniques focused on this kind of image. In active IT an external heat source is used to stimulate the material being inspected in order to generate a thermal contrast between the feature of interest and the background. The active approach is adopted in many cases given that the inspected parts are usually in equilibrium with the surroundings [9].