METHOD FOR COMPENSATING DEFINITION IN ACCORDANCE WITH CHANGING OF TEMPERATURE IN SCANNING SYSTEM

摘要

PURPOSE: A method for compensating a definition in accordance with a changing of temperature in a scanning system is provided to update one luminescence diode by detecting a shading correction element with respect to one luminescence diode again and to compensate a change of light quantity in accordance with the variation of the circumference temperature by compensating on-time of the remainder luminescence diode if a quantity of light is changed at the luminescence diode in a scanning system using a color CIS. CONSTITUTION: A scanning control unit drives a red LED out of LEDs during a turn-on time stored in a LED driving data storing unit for performing a shading process(S401). If a light reflected in the red LED is reflected on a white panel and inputted to a CIS, the CIS converts the inputted reflecting light into an electric analogue image signal and outputs a predetermined voltage signal(S402). A circumference temperature detecting unit decides whether light quantity of the red LED is increased compared to the initial light quantity in accordance with a control of the scanning control unit(S403). If light quantity of the red LED is increased, the scanning control unit confirms whether the increased light quantity of the red LED exceeds to 30 percents(S404). If the increased light quantity of the red LED does not exceed to 30 percents, the scanning control unit confirms digital image data outputted from an analogue/digital conversion unit and checks the saturation pixel number(S405). Turn-on times of green and blue LEDs corresponded to the checked saturation pixel number are detected(S406). A shading data detecting unit scans the white panel and detects shading data and stores the shading data in a shading memory(S407). The scanning control unit outputs digital image data shading-corrected with respect to an actual document referring to the turn-on times of green and blue LEDs(S408).