The scanning nozzle hot air system for thermographic detection of the surface incorporated hidden defects is proposed. Subsurface defects in the sample are detected using the high resolution thermal imaging camera FLIR SC7000. To introduce additional energy in are searched sample, a scanning hot air (about 110°C) nozzle is applied (a patent application P.403346). The hidden defect causes a temperature increase in comparison with the remaining area what is a result of changes in emissivity. The results are compared with the pulse thermography method using the xenon lamp for excitation.