Title:
PICTURE INPUT DEVICE
Document Type and Number:
Japanese Patent JPS6310973
Kind Code:
A
Abstract:
PURPOSE:To attain a binary code without generating noise by previously storing the reading result of a ground part of a drawing in a correction data memory as correction data, subtracting the reading data of the drawing to obtain the reading data. CONSTITUTION:A photodetector 6 reads the ground part of the drawing 1, the density data is A/D converted by an A/D converter 7 and stored via a change over switch 14 in the correction data memory 11 as background density data BGD. Then, the photodetector 6 reads the drawing 1, the density data is inputted to a density data subtracter 12 as a digital density signal PD. The subtracter 12 subtracts the background density data BGD from the digital density signal PD. When the subtraction result PD1 is a negative, the output data of the subtracter 12 is fixed to zero. Thereby, even when the type of the drawing 1 is changed and the density of other part (background density data BGD) is changed, the subtraction result PD1 is hardly changed and it is not required to rewrite and correct threshold data THD.
Inventors:
SOTOZONO HIROSHIGE
Application Number:
JP15402586A
Publication Date:
January 18, 1988
Filing Date:
July 02, 1986
Export Citation:
Assignee:
HITACHI SEIKO KK
International Classes:
H04N1/401; G06T5/00; H04N1/40; (IPC1-7): G06F15/68; H04N1/40
Domestic Patent References:
| JPS59161177A | 1984-09-11 |
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