| 摘要 |
PURPOSE:To read images with a high precision even in case of a large number of gradations and a high resolution by taking white reference data and black reference data of each element and equally dividing the difference to generate correction data. CONSTITUTION:When black reference data Db is outputted from an image sensor, data Db is digitized by an A/D converter 1 and is stored in a RAM for each element. White reference data Dw is stored in a RAM 5 similarly. When an original is read, picture data Df of a certain element is outputted, and data Db and Dw corresponding to this element have signs inverted and are outputted from RAMs 3 and 5, and a Df-Db signal (i) and a Dw-Db signal (n) are outputted by calculation in adders 7 and 9. A signal (m) and the signal (n) are given as the upper-order address and the lower-order address to a ROM 10, and correction data Dr is outputted from the ROM 10. Shading correction and black correction are simultaneously performed by this constitution.
|
