| 摘要 |
A flicker is caused by a light lit on a commercial AC power. An iris priority camera cannot fix a shutter thereof to a shutter speed at which no flicker occurs. Each of images picked up by a surveillance camera provides precious information. Therefore, even when the shutter is set to a high shutter speed, images devoid of an afterimage or a blue have to be picked up even from a subject which makes movements. When a decision is made that a flicker is present, the timings of applying a discharging pulse and a charge readout pulse respectively are varied depending on a field in order to implement shutter speed control in a CCD sensor, so that a camera can be exposed to a portion of light falling into the same phase thereof within a luminescence period of a lighting during each field. The CCD sensor can be exposed to the light without occurrence of a flicker even when a light source emits light while being repeatedly lit and extinguished.
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