Pre-processing of signals delivered by a new eddy current sensor for non ferromagnetic tubes testing

New eddy current sensors, with separated exciting coil and field detectors, will allow one to compute, with tomographic tools, an image of the conductivity at all points of the pipe under test. However, the amount of calculations necessary is very large and, for a realistic usage, it would be more effective to work only on the portion of the tubes where flaws are suspected. In this paper, we propose a fast and efficient pre-processing to detect the presence of a flaw, using the tools of the detection of abnormal values in a data stream. Applied to real signals, this pre-processing gives good results