| 摘要 |
PURPOSE:To prevent read accuracy from deteriorating by scanning a marked surface with a light cutting image, generating two-dimensional distance distribution data to the marked surface from the result of the scanning, and recognizing the distance difference between a marked character part and the marked surface from the two-dimensional distance distribution data and reading characteristics. CONSTITUTION:Slit light SI is projected on the marked surface 12 at right angles to the array of marked characters and linear distance data on a light cut part is generated from the light cutting image SV of the light cut part cut with the slit light SI. Then the two-dimensional distance distribution data on the marked surface 12 is generated from the scanning position of scanning of the light cutting image SV in the array direction of the characters and linear distance distribution data. Then the generated two-dimensional distance distribution data is converted into a light-shade image signal, from which the distance difference between the marked character part 14 and marked surface 12 is recognized to read the characters. Consequently, the characters marked in the marked surface 12 are accurately read even if there are various factors which deteriorate the read accuracy on the marked surface 12 on an object to be read.
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