A controller for an LCD display is described. The controller can control an LED backlight that includes an array of LED lighting elements and an LCD panel that includes a number of pixels. The controller can modulate an individual or groups of the lighting elements in the LED backlight, such as dimming lighting elements, to control a light-field emitted from the LED backlight. The modulation of the lighting elements, such as dimming, can improve image contrast ratios that are generated using the LCD display. Methods and apparatus are described that can simplify calculations used to determine 1) the light-field generated by the LED backlight and 2) a correction factor for adjusting pixel data. The correction factor can be used to adjust an amount of light transmitted by each pixel in the LCD panel to compensate for the backlight producing a light-field that is brighter in some areas and dimmer in other areas.