Liquid crystal display device and image display method thereof

A liquid crystal panel displays an image from image signals. A backlight device is disposed on the back side of the liquid crystal panel, and is divided into a plurality of regions. The backlight device comprises light sources in each of the regions. The light sources are positioned to emit light onto the liquid crystal panel. A histogram detector detects an image signal gradation distribution for each region and to produce a histogram therefrom. An image gain calculator calculates a gain from the detected gradation distribution of the histogram detector, and controls light emission from each light source in each region of the backlight device. A light emission luminance calculator controls the light emission luminance of each light source based on a maximum luminance of the light sources and based on an inverse number of the gain calculated in the image gain calculator.