Model Based Microwave Non Destructive Testing of Pipes

The problem of non destructive microwave testing of pipes has been addressed to evaluate the effectiveness of the technique based on the measurement of the scattering parameter S11. An asymmetric bifilar transmission line has been used to acquire data to be used in the defect modeling, being the pipe to be tested one of the two wires in the line, and a normal copper wire the other. The proposed data preprocessing to be used in a defect classification system is the focus of the paper. A linear time invariant convolving model of the defect is presented to take care of the experimental data acquisition setup. The assumption is that proper modeling can enhance in distinguishing different defects in the measurement system. The technique to extract the model from the acquired data is presented, together with a few experimental results conducted on real acquired data.