Compensation voltage generating apparatus for multipicture display and video display including the same

摘要

Average picture levels of a first video signal (for example, a parent picture signal) and a second video signal (for example, a child picture signal) are detected at first and second APL detection circuits, respectively. A compensation voltage sharing circuit inputs a compensation voltage, for example an ABL/ACL compensation voltage, and shares the compensation voltage according to a ratio of the APL values detected at the first and the second APL detection circuits. The shared compensation voltages are added to the first and the second video signals at the first and the second video processing circuits, respectively. The processed video signals are synthesized at a synthesizing circuit and the synthesized video signal is displayed on a screen of a display device as a multipicture, in which the first and the second pictures are independently and properly compensated by the ABL/ACL function. Thus, a good quality multipicture can be seen.