Infrared Thermography And Thermal Tomography Reconstruction

Infrared thermography has drawn attention and been applied widely due to its non-contactness, rapidity, capability of imaging large area, and has becoming a new non-destructive testing and evaluation technology. Modern electronics and signal processing technology, especially advances in image processing technology, has played a significant role in promoting the development of nondestructive testing technology of the infrared thermography. In this paper, based on the relationship between the surface thermal image sequences acquired at different time points and the inner structure of object, we get the detailed image of inner structure of object by using thermal tomography reconstruction technique.Thermal excitation source and detection system have a direct impact on the results of infrared thermography, so the experiment system of infrared thermography is set up to study infrared thermography under different excitation and with different defects. Because external disturbing and surface conditions have seriously influence on the result of infrared thermography, so it is important and fundamental to rule out the influence and improve observation. Though good results have been yielded, due to the different influences, new approaches continue to emerge. In this paper, using mathematical morphology approach to study the infrared thermal wave image preprocessing, many methods based on mathematical morphology such as noise filtering, defect center extraction and image segmentation are proposed.Tomographic reconstruction is the ultimate goal and form of quantitative non-destructive testing, and it is also very significant for the assessment of the damage. In this paper, according to the characteristics of infrared thermography, a reconstruction algorithm based on the iso-surface projection is proposed, and the reconstruction results show that this algorithm is very good for the reconstruction of subsurface structural information.APDL, the advanced analysis technology of ANSYS, is also employed for the analysis of relationships between time and the surface temperature of the object in this paper. The simulation results of objects with various defects under the modulation of amplitudes and frequency are generated. And then the analysis of the relationship between surface temperature and modulation amplitude and frequency is done.The foundation of the phase-based thermal tomography reconstruction is given.