This paper presents the analysis of the influence that black surface paint layers have on the differences in the results obtained from numerical modelling and those obtained experimentally. Surface paints are commonly used for the purposes of pulse experiments in order to increase the sample surface emissivity and help enhance the signal obtained. The paper argues that it is important to include these paint layers in the numerical analysis either directly, as additional material layer, or alternatively, to estimate their influence and take it into account when comparing the corresponding results. IntroductionInfrared thermography is a method of non-contact surface temperature measurement. The measurement principle is based on the radiation law, which puts into relation the energy radiated from the object's surface and its surface temperature. Two different surfaces do not necessarily radiate the same amount of energy when they are at the same temperature. The amount of energy emitted depends also on the object surface emissivity, a coefficient ranging from 0 to 1 and putting into relation the energy emitted from the real object surface at a given temperature and the energy that the ideal blackbody surface would emit at the same temperature. The higher the surface emissivity, the closer the real object surface to the ideal blackbody surface and the higher the quantity of energy emitted at a given temperature.In non-destructive testing, more often than not, surface characteristics of materials that are subject to pulse thermography (or other IR thermography) testing procedures, have poor surface emissivity properties. In the case of different metals, such as aluminium and steel, emissivity values range from 0.1 to 0.4 [1]. Knowing already that the thermal signal has a relatively low signal to noise ratio (SNR), especially when the temperatures obtained are not much higher with respect to room temperature, different strategies of signal enhancement are commonly used [2]. High emissivity surface paints (ε>0.95) are applied on tested sample surfaces prior to experiment in order to increase the signal that is emitted from the sample surface and captured by the IR camera. Those layers of paint are often neglected when thermal contrast analysis is made, assuming therefore that their influence on the experimental results is negligible. An experiment, in which a metal flat-bottom hole sample plate was tested, revealed large differences when the results were compared between the black-painted region and a small region where the surface black paint fell off over the time. This observation encouraged further research which was directed towards a Plexiglass model. It was expected that Plexiglass was to be easier to work with due to its lower conductivity and, therefore, to the slower rate at which the changes in the sample appear during the experiment, thus making it easier to see the differences. As a result of that research, this article demonstrates to what extent the surface paints can influence the maximum therma...

A hybrid approach, combining thermographic signal reconstruction (TSR) and pulsed phase thermography (PPT), is proposed and tested for the depth estimation of subsurface defects from pulsed thermographic data. First, TSR is used to obtain the polynomial coefficients from raw data. A synthetic thermogram sequence is then reconstructed from the obtained coefficients. Finally, quantitative PPT is applied to this sequence for defect depth estimation purposes. This combined procedure allows to considerably reduce signal noise, improving depth estimation results as a consequence. A TSR module has been added to an existent graphical user interface (ir_view) to perform these operations.

In this study an ancient fresco (Incoronazione dell'Assunta, 15 th century) in the Santa Maria di Collemaggio Church (L'Aquila, Italy) containing real damage due to the earthquake of April 2009, which seriously damaged the structure, was inspected by active InfraRed Thermography (IRT) and Near-InfraRed (NIR) Reflectography. On the other hand, the fresco's condition prior to the earthquake was analyzed by Electronic Speckle Pattern Interferometry (ESPI) and Digital Speckle Correlation (DSC). Thermographic inspection data was processed using Principal Component Thermography (PCT) and Pulsed Phase Thermography (PPT), in order to improve the signature of the defects and to reduce the impact of non-uniform heating and emissivity variations due to the painting's pigments. This work also shows that the integration of the non-destructive techniques mentioned above, constitutes an interesting alternative for the in situ inspection of frescoes without impairing their integrity. On the sidelines of the discussion are also reported further analysis by IRT and Ground Penetrating Radar (GPR), which helped to fill gaps in the construction history of the original Church.

In this paper a review of the state of the art has been presented on Infrared face recognition. A comprehensive review of the state of the art has been already done in [1] in 2008. Our review is a complement of the mentioned work [1] with more emphasis given to more recent or more important publications. Initially, we will review the basic important works on Infrared Face Recognition before 2008. Afterwards, we will focus on the recent works which are not reviewed in [1]. Finally, we will draw the conclusions.

Infrared Thermography (IT) is a good tool for real-time inspection of join welds since the welding process involves large release of heat. This topic has been in fact widely studied in the literature some years ago, example, ref [1]. At that time, in the 90s, infrared (IR) cameras were bulky, nitrogen-cooled so that plant-floor applications were not practical. New technology of small rugged IR cameras allows this application to be seriously revisited, especially with also the powerful available processing power offered by today computers which allows sophisticated algorithms to be deployed real-time. Digital industrial radiography (DIR) also introduced a real time inspection trough the usage of flat panel digital detector. The flat panel usually utilise amorphous silicon (aSi) or complementary metal oxide semiconductor (CMOS) detector arrays with thin film transistors for read out control and photo diodes covered with a fluorescence screen for light conversation. With an acceptable spatial resolution and noise power spectrum level, the flat panel is the most appropriate tool for this purpose. Although it is less possible to obtain real time radiographs of seam weld in very robust environment, comparison studies between IT and DIR is of interest. In fact, the two techniques can be seen as complementary. IT is sensitive to close to the surface "defects" while DIR technique probes through the specimen trough the usage of real time flat panel detector. The fusion of information from those two NDT techniques can thus bring valuable information on the used welding process yielding to improved quality. An experiment is performed for both techniques on a welded steel plate. In the full paper, these issues will be discussed in details and pertinent results will be presented supporting those assessments.In the full paper, these issues will be discussed in details and pertinent results will be presented supporting those assessments.