| 摘要 |
PURPOSE:To attain recognition of characters and frames by dividing an output of a photoelectric conversion element, by binarizing one, by binarizing the other after substracting a constant bias value, and by taking an exclusive OR of the output of two binary circuits. CONSTITUTION:A case 1 contains a light source 3 and photoelectric conversion element 4 inside it and slides the case on an object 2 to be read while moving the case. A reflected light of characters and frames on the object 2 irradiated by the light 3 is incident on a photoelectric conversion element 4 to obtain a current signal proportional to light intensity, and is amplified by an amplifier 5. A differential amplifier 6 multiplies a difference of a photoelectric conversion element output X and a bias value alpha by (a). A binary circuit 8 compares an output Y of the amplifier 6 with a threshold gamma and binarizes it. A binary circuit 7 compares an output X of the element with the first threshold beta and binarizes it. An exclusive OR circuit 9 calculates an output W of the circuit 7 and 8, and exclusive OR of Z.
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