| 摘要 |
PURPOSE: An apparatus for automatically correcting an external video signal offset is provided to easily detect an effective video portion of an external video signal using a digital circuit without using a conventional analog circuit. CONSTITUTION: An apparatus for automatically correcting an external video signal offset includes a dark region detector, a horizontal and vertical resolution controller, and a horizontal and vertical image effective position detector. The dark region detector compares an input image with an upper level threshold value and a lower level threshold value, respectively, to generate a dark region flag. The horizontal and vertical resolution controller controls resolution according to the dark region flag. The horizontal and vertical image effective position detector finds out an effective image region corresponding to the controlled resolution.
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