| 摘要 |
PURPOSE:To correct the density of an analog picture signal without adversely affecting its accuracy by converting digitally the analog picture signal outputted by an image sensor by retaining a non-linear characteristic. CONSTITUTION:A/D converters 1530-1532 execute A/D converting actions according to one function D=-log R (where D: optically reflecting density; R: reflectance) in light of the density correction (gamma correction) with respect to the picture signal. Thanks to these converting actions a reference voltage impressed between plural reference voltage setting terminals is not divided into the same amounts although the reference voltage necessary for quantization is supplied to the A/D converters 1530-1532 from the outside, and a nonlinear voltage 1534 is supplied to approach it to a kinded-line function. Analog chrominance picture element signals VB, VO and VR, that is, data on the reflectance whose polarity is A/D-converted in terms of logarithm to be inverted in such a way, go to density data having digital amounts DR, DO and DB of eight bits the moment they come out of the A/D converters 1530-1532, and are transmitted to a main body.
|
