| 摘要 |
PROBLEM TO BE SOLVED: To obtain projection video in an optimum lightness display state even if it is dark in the circumference. SOLUTION: The analog video signal from a video input circuit 11 is supplied to a video input mean value detecting circuit 17 to calculate a mean value of luminance, and the level of the inputted video signal is used to detect, for example, dark video, standard video, or light video. Based upon this detection information, a reference switching circuit 18 switches a reference level of lightness to be the reference for classifying the video lightness into a plurality of pieces such as dark video, standard video, and light video. According to the indication, the reference level value is inputted from a reference data storage part 19 to a comparator 21. Further, illuminance information on ambient light is inputted from an OPC 20 and the comparator 21 compares those input values to select an optimum gamma table. COPYRIGHT: (C)2005,JPO&NCIPI
|
