| 摘要 |
PURPOSE:To obtain red, green and blue data on the same position in a main scanning direction and to reproduce a color image of high picture quality by setting up the reading density of red and blue picture elements almost to the same reading density of green picture elements by interpolation processing. CONSTITUTION:Signals outputted from CCD linear image sensor output buffers 11, 12 are respectively amplified by differential amplifiers 14a, 14b and then converted into digital data by respective A/D converters 20, 21. Shading correcting circuits 19a, 19b for uniforming light distribution characteristics respectively include black/white correcting memories 16a, 16b and D/A converters 17a, 17b, 18a, 18b. In an initial state, a black original is read out, the output levels of respective sensors are stored, converted into analog signals and fed back to the amplifiers 14a, 14b so that the differences of respective sensors from the black level can be always amplified. Then, a white original is read out in the initial state, respective white levels outputted from respective sensors are stored and inputted to the converters 20, 21 as reference levels. The interval between the white level and the black level is divided into prescribed gradations, the level of one bit is determined and shading correction is executed. |
