| 摘要 |
<p>PURPOSE:To obtain a monitor pattern whose picture quality is not deteriorated even if a fluorescent light lighted by a commercial power supply is in use by generating a signal of the same waveform as a flicker component from an AC power supply used for lighting in a television conference system, subtracting it from a moving picture signal and inputting the result to an inter-frame difference coding transmitter. CONSTITUTION:The output of the AC power supply 1 used for lighting is subjected to full wave rectification by a full wave rectifier circuit 2, and the phase and amplitude are adjusted by a delay adjustment circuit 3 and an amplitude adjusting circuit 4, and the resulting waveform is subtracted from a moving picture signal of a video camera 5 by a subtraction circuit 6 and the result is sent. Thus, even when the AC power supply 1 used for the lighting is a commercial power supply and the flicker component from the fluorescent light is superimposed on the moving picture signal from the video camera 5, the flicker component equivalent to said flicker component is eliminated by subtracting it by the subtraction circuit 6. As a result, the inter-frame difference coding transmitter is acted normally and the deterioration in the picture is prevented in displaying the picture on a monitor television using the other frequency. Since no expensive high frequency power supply is required especially, the flicker eliminating system is formed inexpensively.</p> |
