Liquid Crystal Display Image Processing Reducing Halo Artifacts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices with multiple superposed panels face issues with image quality degradation, particularly when displaying bright portions on a black background, due to halo and double image formation, which are challenging to address without compromising contrast or introducing picture lacking.
Innovation Solution
An image processing device generates a second output image signal for a second liquid crystal panel by applying gamma correction and detecting high-frequency portions to adjust gradation values, reducing halo and double image formation while maintaining high contrast ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple liquid crystal panels are superposed to improve contrast ratio, then contrast ratio is improved, but image quality degrades due to halo and double image formation
Solution Approach 1:
The image processing is segmented into multiple stages: gamma correction, high-frequency detection, and selective gradation correction. This segmentation allows the system to address different aspects of image quality independently, correcting halo and double image artifacts without compromising the contrast ratio improvement achieved through panel superposition.
Solution Approach 2:
The patent applies local quality correction by detecting high-frequency portions in the image and selectively adjusting only those regions. The second corrector decreases gradation values specifically in detected high-frequency portions, leaving other regions unchanged. This localized approach prevents halo and double image formation in critical areas while preserving the overall contrast enhancement from the multi-panel configuration.
2Illumination intensity
If gamma correction is applied to correct gradation values, then image brightness is improved, but halo and double image artifacts appear in high-frequency regions
Solution Approach 1:
The system performs preliminary gamma correction on the entire image to ensure proper brightness and contrast, then subsequently detects high-frequency portions and applies additional selective correction. This preliminary action followed by targeted correction allows the system to first establish overall image quality, then address specific artifact problems in high-frequency regions without compromising the global brightness correction.
Solution Approach 2:
The detector provides feedback about high-frequency portions to the second corrector, creating a closed-loop system. The detector identifies regions where halo and double image artifacts are likely to occur, and this information feeds back to the second corrector which then applies targeted gradation value adjustments. This feedback mechanism ensures that brightness correction does not inadvertently create image quality degradation.
3Device complexity
If conventional image processing is used in multi-panel displays, then device complexity is reduced, but picture lacking occurs in high-contrast regions
Solution Approach 1:
The image processing pipeline is divided into distinct functional blocks: a first corrector for gamma correction, a detector for high-frequency portion identification, and a second corrector for selective gradation adjustment. This segmentation maintains manageable device complexity by organizing processing tasks into modular, independent stages, each with a specific function, while collectively achieving superior image quality in high-contrast regions.
Data Source
AI summary
An image processing device that generates a second output image signal output to a second liquid crystal panel that is disposed to be superposed on a first liquid crystal panel, includes: a first corrector that generates a gamma correction signal in which a gradation value of an input image signal is corrected; a detector that receives the gamma correction signal and detects an image region brighter than surroundings as a first high-frequency portion from the gamma correction signal; and a second corrector that receives the gamma correction signal and a detection result of the detector and performs correction to decrease the gradation value of the first high-frequency portion in the gamma correction signal. The second output image signal is generated based on the gamma correction signal corrected by the second corrector.