Display Brightness Adjustment via Gamma Correction
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Solution Overview
Problem
Electronic displays often exhibit variations in maximum brightness due to differences in materials, manufacturing processes, and operational parameters, leading to inconsistent brightness when multiple displays are viewed side by side, which can affect contrast fidelity and consumer preference.
Innovation Solution
The method involves adjusting the gamma correction curves and look-up tables in video cards to shift the middle tone levels of display signals, while maintaining relative contrast, allowing for real-time brightness adjustment without increasing power consumption, thereby synchronizing the apparent brightness of multiple displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the maximum brightness of a display is increased by varying current or voltage to the display pixels, then the brightness is improved, but the contrast fidelity deteriorates and color becomes washed out
Solution Approach 1:
The patent segments the display signal into different tone ranges (shadows, mid-tones, highlights) and applies different processing to each segment. The gamma correction lookup table is divided into multiple regions, with mid-tone signals being selectively boosted while shadow and highlight signals are preserved, thereby increasing apparent brightness without sacrificing contrast fidelity across the entire image
Solution Approach 2:
The patent applies local quality enhancement by specifically targeting mid-tone signals for brightness enhancement while leaving shadow and highlight regions unchanged. This localized approach to signal processing ensures that the apparent brightness of the display is increased without degrading the contrast fidelity in critical regions
2Illumination intensity
If the brightness of multiple displays is made consistent through manufacturing control, then the brightness uniformity is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the signal processing parameters (gamma correction lookup table values) to compensate for display brightness variations. By adjusting the mid-tone signal boost amount based on the specific display's characteristics, the system achieves brightness consistency across multiple displays without requiring precise manufacturing control
Solution Approach 2:
The patent implements a feedback mechanism where the system measures or determines the actual brightness characteristics of each display and adjusts the signal processing parameters accordingly. This closed-loop approach enables automatic compensation for manufacturing variations, simplifying the overall manufacturing process
3Illumination intensity
If the middle tone signals are boosted to increase apparent brightness, then the apparent brightness is improved, but the shadow and highlight details may be lost
Solution Approach 1:
The patent segments the signal processing into distinct regions (shadows, mid-tones, highlights) and applies selective boosting only to the mid-tone region. This segmentation ensures that shadow and highlight details are preserved while still achieving apparent brightness enhancement through mid-tone signal amplification
Solution Approach 2:
The patent applies local quality enhancement specifically to the mid-tone region of the image signal, leaving the shadow and highlight regions unchanged. This localized processing approach increases apparent brightness while maintaining detail integrity in the extreme dark and bright regions
Data Source
AI summary
Methods and apparatuses to varying the apparent brightness of a display are described. The change in apparent brightness is accompanied by unchanged in relative contrast, rendering a display with higher or lower brightness while maintaining contrast fidelity. In exemplary embodiments, the signals for the middle tone levels are adjusted to increase or decrease the brightness intensity, while keeping constant the gamma correction. This maintains the relative contrast of images while rendering them at a different brightness. Implementations of the present process include an adjusted gamma correction lookup table, incorporated in the video card to modify the video signal before reaching the display. The present invention can be used for matching the brightness of two or more displays or to provide compensation for variations in display characteristics to ensure consistency in display brightness within a data processing model.