IMAGE READING-AND-TRANSFERRING SYSTEM UTILIZING COMPUTER OF TONE DATA

An image scanner produces white level data when the white plate is irradiated with light. The image scanner produces black level data when the white plate is irradiated with no light. Correction data constructed from the thus produced white level data and black level data is transferred to the host computer. Next, the image scanner produces tone data for the original, and transfers the tone data to the host computer. In the host computer, the tone data is corrected into either one of the 256 levels "00" to "FF." This correction operation is attained with using average values of the transferred white level data and average values of the transferred black level data.