Display Data Processing Device White Point Adjustment
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Solution Overview
Problem
Existing display technologies face issues with image quality deterioration during white point adjustment, such as gray gradation, crushed shadows, and flickering, due to varying gradation characteristics of color components R, G, and B, and the need for frequent gamma LUT recalibration, which affects the speed and continuity of color adjustment.
Innovation Solution
A display data processing device with a first gamma correction unit and a video gain correction unit that adjust gradation values based on specific gamma characteristics and power functions, ensuring consistent brightness and chromaticity changes, and a second gamma correction unit that maintains the same power function for seamless color adjustment without requiring frequent gamma LUT recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gamma LUT recalibration is performed frequently to maintain accurate color reproduction, then color accuracy is improved, but adjustment speed and continuity deteriorate
Solution Approach 1:
The patent pre-calculates and stores correction values for multiple gamma characteristics in advance. When white point adjustment is needed, the system simply switches between pre-computed correction tables rather than recalculating in real-time, enabling both accurate color reproduction and fast adjustment response.
Solution Approach 2:
The patent implements dynamic selection of gamma correction characteristics based on the current white point adjustment state. The system can smoothly transition between different gamma characteristics (e.g., from gamma 2.2 to gamma 2.4) without requiring full recalibration, maintaining both accuracy and speed.
2Speed
If video gain correction is applied to adjust white point, then color adjustment speed is improved, but image quality deteriorates due to gray gradation and crushed shadows
Solution Approach 1:
The patent changes the gamma characteristic parameter (gamma value) rather than simply adjusting video gain. By modifying the gamma correction curve, the system achieves white point adjustment that maintains proper gradation characteristics across all brightness levels, avoiding the crushed shadow and gray gradation problems associated with pure gain adjustment.
Solution Approach 2:
The patent combines multiple correction methods: gamma characteristic switching, video gain correction, and offset adjustment work together in a composite correction system. This multi-layered approach allows the system to achieve both fast response and high image quality by distributing the correction across different stages.
3Measurement precision
If gamma characteristic changes during white point adjustment, then white point accuracy is improved, but gradation characteristics vary causing image quality deterioration
Solution Approach 1:
The patent applies different correction strategies to different parts of the correction pipeline. The gamma correction unit handles the overall characteristic adjustment while the video gain and offset units handle local brightness and contrast adjustments. This localized approach ensures that each stage contributes to white point accuracy without disrupting the overall gradation stability.
Data Source
AI summary
A display data processing device performs color adjustment on gradation values of pixels of a frame image of an input video signal and outputs the adjusted gradation values to a display device. The device includes a first gamma correction unit configured to set the gradation value as the first input gradation value and to convert the first input gradation value into the first corrected gradation value. The device includes a video gain correction unit configured to perform color adjustment on the first corrected gradation value according to video gain correction and to output the result as a video gain corrected gradation value. The device includes a second gamma correction unit configured to set the video gain corrected gradation value as the second input gradation value and to convert the second input gradation value into the second corrected gradation value.