Image display apparatus
View Patent ↗An image display apparatus for displaying images based on signals of an input image is provided. A backlight emits light. A liquid crystal panel modulates light emitted from the backlight. A emission intensity calculating unit calculates an emission intensity of the backlight such that a center value of a lightness range displayable on the panel defined depending on the emission intensity of the backlight substantially agrees with a center value between maximum and minimum values of lightness of each signal of the input image. A backlight controlling unit controls light emission of the backlight such that the light is emitted with the emission intensity. A signal correcting unit corrects each signal of the input image in accordance with the emission intensity. A liquid crystal controlling unit controls modulation of the liquid crystal panel based upon the corrected signals.
1. An image display apparatus, comprising:
a backlight configured to emit light;
a liquid crystal panel configured to modulate light emitted from the backlight to display an image on display area;
an emission intensity calculating unit including an acquiring unit configured to acquire a maximum value and a minimum value of lightness of an target image signal, a center value calculating unit configured to calculate a first center value, the first center value being a half of a summed value of the maximum value and the minimum value, and an intensity calculating unit configured to calculate an intensity of the backlight such that a second center value of a lightness range being displayable on the display area substantially coincides with the first center value;
a backlight controlling unit configured to control emission of light by the backlight in accordance with the intensity of the backlight;
a signal correcting unit configured to correct the target image signal in accordance with the intensity of the backlight; and
a liquid crystal controlling unit configured to control the liquid crystal panel based upon the corrected target image signal.
2. The apparatus according to claim 1 , wherein
the signal correcting unit corrects the target image signal by dividing luminance of the target image signal by emission luminance depending on the intensity of the backlight.
3. The apparatus according to claim 2 , wherein
the emission intensity calculating unit includes a low-pass filter which performs low-pass filtering on the target input signal, and
the center value calculating unit calculates the first center value based on the target input signal after low-pass filtering.
4. The apparatus according to claim 2 , wherein
the emission intensity calculating unit includes a resolution converting unit configured to convert a spatial resolution of the target input signal to a lower resolution, and
the center value calculating unit calculates the first center value based on the target input signal after resolution conversion.
5. The apparatus according to claim 1 , wherein
the intensity calculating unit multiplies the first center value by a predetermined constant number to obtain the intensity of the backlight.
6. The apparatus according to claim 5 , wherein
the predetermined constant number is calculated based on a dynamic range of the liquid crystal panel.
7. The apparatus according to claim 1 , wherein
the backlight includes a plurality of light sources each of which are individually controllable with respect to intensity of each of the light sources, and
the emission intensity calculating unit calculates the intensity of each of the light sources based on each corresponding signal of the target input signal within a spatial range depending on an irradiation range by each of the light sources to the liquid crystal panel.