| 摘要 |
The present invention is directed to a video camera which comprises an image sensing device for sensing an incident light to generate charges and supplying an output signal corresponding to the charges, the output signal comprising a recurrent vertical scanning period and a recurrent vertical blanking period, the vertical scanning period including a plurality of horizontal scanning periods, a comparator for comparing a level of the output signal with a reference level to generate a compared output signal, a circuit for generating a first clock pulse having the same frequency as a horizontal scanning period, a circuit for generating a second clock pulse having a frequency higher than that of the first clock pulse, and an exposure time controlling circuit for receiving the compared output signal and controlling an exposure time of the image sensing device in synchronism with the first clock pulse according to the compared output signal when the exposure time is within the vertical scanning period, and the exposure time controlling circuit controls the exposure time in synchronism with the second clock pulse when a whole exposure time is within a vertical blanking period.
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