Adaptive Backlight Control for Display Contrast Enhancement
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Solution Overview
Problem
Conventional techniques for reducing backlight power consumption in display devices, such as LCDs, often compromise image contrast, leading to reduced display fidelity and distortion in pixel representation.
Innovation Solution
A display system that analyzes pixel data to generate a transform function with multiple points, enhancing image contrast and adjusting backlight intensity based on average contrast and brightness, allowing for reduced power consumption without significant image quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If backlight intensity is reduced to decrease power consumption, then energy efficiency improves, but image contrast deteriorates
Solution Approach 1:
The patent applies parameter changes by transforming pixel values through a contrast enhancement function that adjusts the distribution of brightness values. This allows the system to maintain perceptible contrast at lower backlight intensities by redistributing pixel luminance values to maximize visible difference between dark and light regions without requiring increased backlight power.
Solution Approach 2:
The contrast enhancement is applied as a preliminary processing step before display output. By pre-adjusting the pixel values to optimize contrast perception, the system prepares the image data in advance so that subsequent reduction in backlight intensity does not compromise the perceived image quality, thus enabling energy savings without contrast loss.
2Illumination intensity
If LCD transmittance is increased to maintain brightness, then display fidelity improves, but power consumption increases
Solution Approach 1:
The system changes the parameter distribution of pixel brightness values through contrast enhancement, transforming the histogram of pixel intensities to maximize contrast. This allows the display to maintain adequate brightness perception through optimized value distribution rather than through increased backlight power or transmittance, thereby avoiding the energy consumption trade-off.
3Illumination intensity
If histogram stretching is applied to salvage image contrast, then contrast is improved, but pixel distortion occurs in brightest and darkest regions
Solution Approach 1:
The patent implements a contrast enhancement function that transforms pixel values through a controlled parameter change process. Unlike aggressive histogram stretching that clips extreme values, this function applies a monotonic transformation that preserves the relative ordering of all pixel values while expanding the contrast range, thereby avoiding distortion in the brightest and darkest regions while still enhancing overall image contrast.
Data Source
AI summary
A transform function represented by at least n points that define n−1 regions is determined based at least in part on a first set of values associated with a display frame and a maximum average contrast function. The n points can be determined in response to a change in an average contrast of the display frame compared to an average contrast of a previous display frame exceeding a predetermined threshold. The first set of values is converted to a corresponding second set of values based on the transform function. A backlight control signal is generated based on an average contrast of the second set of values, whereby the backlight control signal is configured to control an intensity of a backlight of a display. Further, a video signal is generated based on the second set of values, whereby the video signal configured to drive the display.