| 摘要 |
PURPOSE:To follow and correct the fluctuation of a white part on an original and that of a light source by modifying a reference signal so that a ratio to an image signal can be constant based on the reference signal and executing the shading distortion according to this new reference signal. CONSTITUTION:A dark output signal from an image sensor not giving light on a read surface is outputted from an A/D converter 2, and stored in a ROM 11. Then by giving light to the read surface, a light output signal is outputted from the image sensor, A/D-converted 2 and outputted to a ROM 12. After it calculates the difference between the dark and light outputs, a brightness reference signal IRef becoming a reference signal is stored in RAMs 13 and 14. A ROM 15 executes the shading distortion correction. This calculation is obtained according to a calculation equation, R=IIn/IRef based on the reference signal IRef outputted from the RAM 14 and an image signal IIn when an original is actually read out.
|
