Research on the visual detection technology using eddy current microscope

Visual eddy current testing technology is presented in this paper to test the invisible and buried subsurface flaws in metallic specimens. When coil is excited by intermittent impulse signal, the eddy current effect happens among the tested metal specimen which is near the coil, Because of magnetic-optic effect caused by eddy current magnetic field, the magnetic-optic film changes the polarization direction of the passing linear polarization beam. The beam, containing the defectspsila information can be accepted by CCD after being reflected through beamsplitter, and now the imperceptible flaws in subsurface of mental product can be visually tested. The image processing approaches are introduced in detail. Experimental tests have been done and the method presented is proved to be practicable by the experimental results.