| 摘要 |
PROBLEM TO BE SOLVED: To reproduce information through adequate binarization. SOLUTION: A threshold detection part 20 computes a threshold for binarization in a vertical blanking period according to a maximum value and a minimum value obtained from a video signal of a previous field. When the threshold computation result is not more than a prescribed value, the means that an image is very dark, so proper binarization can not be performed through image pickup operation with the current quantity of light. Accordingly, a system control part performs control for increasing the quantity of irradiation light of an LED as a light source. |
