| 摘要 |
PURPOSE:To execute shading correction with high accuracy without decreasing a read speed by detecting the stable state of luminescent light quantity based on a tube wall temperature of a fluorescent light and executing the shading correction in matching with the timing when the luminescent light quantity is made stable prior to the start of read of an original picture. CONSTITUTION:A tube wall temperature of a fluorescent light 43 heated by a heater 44 is detected by a thermister 44, a heater control circuit 48 applies on/off control to the heater based on the detected temperature to keep the tube wall temperature to a prescribed temperature. When the tube wall temperature of the fluorescent light 43 reaches a prescribed temperature after power-on of a scanner 41, a CPU 54 commands the execution of shading correction to an A/D converter 51 to store the shading correction data to a line memory 52 and the original picture data read one by one line each from an original is sequentially subjected to shading correction based on the shading correction data stored in the line memory 52. |
