| 摘要 |
PURPOSE:To measure non-destructively a fine magnetized pattern with high accuracy by executing the arithmetic processing of an image inputted synchronously with an external magnetic field. CONSTITUTION:A magnetized pattern of a substance 1 to be measured is transferred to a magnetism transferring plate 2 stuck to the substance 1 and consisting of a vertical magnetic film having a magneto-optical effect and reducing its coercive force based on a leaked magnetic field. Since a labyrinthine magnetic domain in an area II of the pattern is not restricted by the leaked magnetic field of the substance 1, the magnetic domain is oscillated by applying an AC magnetic field through an exciting coil 6 and changed to an optional shape. Thereby, the pattern is read out through an optical system 3 provided with a light source 3a, a polarizer 3b, a beam splitter 3c, an analyzer 3e, etc., synchronously with the AC magnetic field and image picked up by a TV camera 4 and the binarization arithmetic of an image pickup signal is executed by an image processor 5 so as to correspond to a bright-dark part, so that the pattern in the area II is removed and a pattern in an area I which is restricted by the leaked magnetic field is measured non-destructively with high accuracy.
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