PURPOSE: To automatically read out a carved pattern embedded on a coated surface by constituting the title reader of a means for magnetizing the surface of a material, a means for reading out the magnetized direction of residual magnetism and a means for recognizing the carved pattern read out by the reading means.
CONSTITUTION: A magnetic writing part 1 generates a magnetic field on the basis of a magnetic field control signal 12 to magnetize the material 9. Since the magnetization ratio of the carved pattern drawn on the surface of the material 9 is changed in accordance with the rough state on the surface, magnetic strength and magnetic angle are changed and the carved pattern part and the material surface are magnetized in the different directions. A detecting array 6 has plural (n sets) magnetizing direction detectors 5 and the detecting array 6 is moved close to the material 9. A recognizing part 4 compares and matches the image data read out from a storage part 3 with the sampling pattern data stored in the part 4 itself to recognize and read out the carved pattern by so-called pattern matching.
TAKAHASHI KATSUNORI
NAKAMURA KOICHI
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