| 摘要 |
PURPOSE:To make an effective use of the dynamic range of a photoelectric conversion element by adjusting the output gain of the said element so that the specific density of a film original causes the output of the said element to come to saturation level. CONSTITUTION:A sensor driver 106 controls the charge-accumulation periods Tr, Tg, Tb, and Tir at the time when reading R(red), G(green), B(blue), and IR(infrared)-picture information so that the R, G, B, and IR picture outputs of a linear sensor 11 come to be in saturation level when the quantity of transmitting light is that when the orange part(natural color) of a film original is irradiated by the light from an illuminating optical system. The accumulation period T of the sensor 11 is so determined that the zero density of the original makes the output of the sensor 11 to be the saturation output voltage Vf. Assuming that the output of the sensor 11 for the orange base part in case a red filter is inserted in the optical path is Vr, the said period T is controlled to satisfy an equation: Tr=TXVf/Vr.
|
