WELD TESTING USING EDDY CURRENT PROBES AND IMAGE PROCESSING

This paper proposes an eddy-current non- destructive weld testing solution that uses a sensing probe including an excitation coil and a giant magneto-resistance sensor. The testing system control and the acquisition tasks are performed using a PXI system that includes a sinusoidal signal generator, a data acquisition module and a XY scanning stage control interface. For different positions of the sensing probe on the aluminum weld plane the eddy currents are detected and the acquired signals are processed. The signal processing is based on the LabVIEW tone measurement function in order to obtain an image representing the detected voltages as a function of the xy coordinates. An image processing block was designed and implemented in order to detect the weld zone anomalies. This block includes normalization, grayscale image filtering and image segmentation algorithms. Results on weld zone characterization for different tested specimens are included in the paper.