Thermal methods of non-destructive evaluation are extremely valuable tools in fault diagnosis and crack detection. They lend themselves extremely well to passive monitoring and control. However, in many cases, it is difficult to fully map the thermal field. Furthermore, infrared thermography cannot access all parts of compact and complex assemblies. The objective of my research is to investigate the application of inverse heat transfer methods in non-destructive evaluation. In other words, it is an attempt to estimate the temperature field using measurements at few points/areas.