Color Adaptive LCD Backlight Control via Channel Histogram Stretching
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Solution Overview
Problem
Current content adaptive backlight control techniques for LCDs are limited in reducing power consumption, especially when color channels are saturated, as they primarily rely on adjusting the backlight based on the highest pixel value, resulting in insufficient power savings.
Innovation Solution
Implementing separate histogram stretching and backlight control for multiple color channels, such as red, green, and blue, allowing independent adjustment of LED arrays to reduce brightness proportionally based on respective stretching factors, thereby optimizing power consumption without impacting image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If separate histogram stretching and backlight control is performed for multiple color channels, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The backlight is divided into multiple LED arrays corresponding to different color channels (red, green, blue), and histogram stretching is performed separately for each color channel. This segmentation allows independent control of each color channel's brightness, enabling greater power savings by dimming only the channels that can be stretched without saturation, rather than uniformly controlling the entire backlight.
2Use of energy by moving object
If the backlight is dimmed to reduce power consumption, then power consumption is reduced, but visibility of the display is degraded
Solution Approach 1:
Histogram stretching modifies the transmittance parameters of pixels to compensate for the reduced backlight intensity. By stretching the histogram, the display maintains proper contrast and visibility even when the backlight is dimmed, as the pixel transmittance values are adjusted to utilize the full dynamic range available with the lower backlight intensity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables greater power savings in LCD backlights by allowing independent dimming of each color channel, even when others are saturated, enhancing the reduction in power consumption without degrading image perception.
Implementation Method 1
backlights comprising two or more light emitting diode (LED) arrays of different color
Data Source
AI summary
A backlight for a LCD comprises two or LED arrays, each corresponding to a respective color channel. A control circuit controls the supply current to each LED array separately based on the content of a displayed image to reduce the current consumption of the backlight. The control circuit generates separate histograms of transmittance values for each of two or more color channels in the image, and stretches the histograms for the two or more color channels by respective stretching factors to generate a stretched image. The stretched image is displayed on the LCD. The control circuit further control the current supply to the two or more LED arrays in the backlight to reduce a brightness of light emitted by the two or more LED arrays in dependence on respective stretching factors for the corresponding color channel.