| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a closed circuit television system capable of measuring a wiring length of a power cable with accuracy even when a voltage value outputted by a power supply device is unknown, and of correcting a video signal based on the measured value automatically and properly. <P>SOLUTION: In a television camera device 1, at the start of power supply, power supply delay means 13 is set to be in a cut-off state to accumulate electric charges in a capacitor C1 in power supply voltage estimation means 12. Thereafter, energization of the power supply delay means 13 is started, the television camera device 1 is activated, and then, a voltage E1 of the capacitor C1, a voltage value E2 applied to the television camera device 1, and a consumption current value I are measured. A storage part 155 stores a resistance value r per unit length of a power cable 4 and a video signal correction factor G corresponding to a wiring length L. A distance calculation part 154 uses those stored values to calculate the wiring length L from an equation of L=ä(E1-E2)/I}/r. A video signal correction factor controller 156 controls a video signal corrector 14 according to the video signal correction factor G corresponding to the wiring length L to correct a video signal. <P>COPYRIGHT: (C)2012,JPO&INPIT |
