Image displaying method, image displaying device, and contrast-adjusting circuit for use therewith
View Patent ↗A system provides an image displaying technique that provides stable high contrast even in an area having high brightness. Based on information about an average brightness level of a digital luminance signal, black-correction processing which decreases a brightness level by offsetting the brightness level to the minus side, and increase processing which increases a contrast gain within a dynamic range, are performed for an analog luminance signal or a digital luminance signal, enabling improvement in contrast even where brightness is intense.
1. An image display device using a fixed pixel device that displays an image based on a video signal, said image display device comprising:
a detector which detects luminance information about an average brightness level of said video signal;
a first processor which performs a black correction to said video signal by using said luminance information detected by said detector; and
a controller which controls a contrast of said video signal to increase within a quantity of said black correction to said video signal greater than or equal to a given value;
wherein said first processor does not perform a black correction under control of said controller when said luminance information is within a range of an average brightness level less than the given value,
and a contrast of said video signal increases under control of said controller corresponding to a quantity of said black correction to said video signal performed by said first processor when said luminance information is within a range of an average brightness level greater than or equal to the given value.
2. An image display device according to claim 1 , wherein said first processor which performs a black correction that decreases a brightness level by offsetting the brightness level to the minus side to said video signal by using said luminance information detected by said detector.
3. An image display device according to claim 1 , wherein a contrast of said video signal increases within a dynamic range under control of said controller.
4. An image display device according to claim 1 , further comprising a second processor which performs a color correction to said video signal.
5. An image display device according to claim 4 , wherein said second processor which performs a color correction to said video signal corresponding to a quantity of said black correction to said video signal performed by said first processor.
6. An image display device according to claim 4 , wherein said second processor which performs a color correction to said video signal when a quantity of said black correction to said video signal performed by said first processor is more than a predetermined quantity.
7. An image display device according to claim 1 , wherein said fixed pixel device is a plasma display panel or a liquid crystal panel.
8. An image display device according to claim 1 , wherein said luminance information about an average brightness level is detected for a period of one frame or one field of video.
9. An image display device according to claim 1 , wherein said first processor performs a black correction to increase corresponding to increase of said luminance information detected by said detector.
10. An image display device according to claim 1 , wherein said controller controls a contrast of said video signal that said black correction is performed by said first processor.