In-depth high-resolution SAR imaging using Omega-k applied to FMCW systems

Imagery applied to non-destructive testing implicitly includes the ability of imaging defects or foreign inclusions inside materials. Within a certain frequency range some nonmetal materials become highly transparent and only media interfaces or defects will scatter signals back to the sensor. Three-dimensional in-depth imaging is therefore possible and synthetic aperture processing can be applied to compensate cost-efficiently several main disadvantages present in typical high-resolution microwave imagery systems using focused beams. This work investigates under the framework of the DOTNAC Project (an FP7 project funded by the European Commission) the possibilities of applying synthetic aperture radar processing to a high-resolution frequency-modulated continuous-wave system for non-destructive testing purposes. The Omega-k range migration algorithm is used to perform efficient range migration of the raw data. This paper shows in-depth SAR images from real composite materials including ad-hoc defects. Assessment of results as well as discussion on the proposed 3-D in-depth imaging system will be presented.