| 摘要 |
PURPOSE:To correct shading distortion while eliminating the effect of fluctuation of luminous amount distribution of a light source by inputting simultaneously an optical signal from an original and a white reference board and processing the signal in parallel so as to simplify the circuit. CONSTITUTION:The reflected light from an original 10 and the white reference board 11 irradiated by the light from a reading light source 12 passes through separate paths 10a, 11a, is reflected on a mirror 13, the reflected light from the original 10 is collected to a linear image sensor 16 and the reflected light from the white reference board 11 is collected to a linear image sensor 15. The signal from both the linear image sensors 15, 16 is inputted to a comparator 21 via amplifiers 17, 18. Then it is possible to binary-code a picture signal at each position of the original scanning based on a slice level corresponding to shading distortion. No memory is required through the parallel processing in this way and no A/D, D/A converter is required resultingly.
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