Detection of the Cavities Inside a Target with Near Field Orthogonality Sampling Method

In this contribution, a recently proposed qualitative imaging technique, Near Field Orthogonality Sampling Method, is applied to screen the cavities inside a target. For this aim, the scattered field measurements from the targets are simulated at microwave frequency range. The obtained data is corrupted with additive white Gaussian noise (AWGN) to prevent any inverse crime. After, assuming that the outer shape and average electrical properties of the scatterer is known, the background data is subtracted from the noisy measurements. Then, obtained difference is directly applied to NOSM algorithm. The interesting properties of the method are in order: (i) the NOSM can operate with a single view - multi static measurement configuration; (ii) the multi-frequency data can be easily integrated into calculation process due to qualitative nature of the proposed method. Obtained results show the usefulness of the NOSM in nondestructive testing applications.