Local Dimming Spatial Filtering for Deep Black Contrast
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Solution Overview
Problem
Conventional local dimming technologies struggle to achieve high contrast and deep black levels, particularly in areas requiring flexible luminance and black characteristics, such as vehicle corners or edges, due to insufficient processing of deep black and real black, leading to low contrast and irregular backlight region illumination.
Innovation Solution
A local dimming technology that calculates representative brightness values through black image data analysis, considering the relative importance of black levels and area non-uniformity between blocks, and differentially applies spatial filtering based on block positions using masks with specific coefficients to adjust backlight dimming values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional local dimming is applied to reduce power consumption, then power consumption is reduced, but contrast and deep black levels deteriorate
Solution Approach 1:
The patent applies different spatial filtering strategies to different regions of the display panel. Center regions use one type of filtering while edge and corner regions use different filtering approaches. This allows each region to be optimized for its specific requirements, maintaining deep black levels in corners/edges while managing power consumption across the entire panel.
Solution Approach 2:
The patent dynamically adjusts the representative brightness value calculation by incorporating black image data analysis and gamma variables. This changes the parameters used to determine dimming levels, allowing for better preservation of black levels and contrast while still achieving power reduction through selective dimming in appropriate regions.
2Device complexity
If spatial filtering is applied uniformly to all regions, then processing simplicity is improved, but deep black and contrast in corners and edges deteriorate
Solution Approach 1:
The patent implements position-dependent spatial filtering where the filtering operation applied to a block depends on its position within the video image. Corner blocks, edge blocks, and center blocks each receive appropriate filtering treatment. This maintains processing simplicity through systematic rules while preserving deep black and contrast characteristics in specific regions.
Solution Approach 2:
The patent divides the video image into different regional zones (corner regions, edge regions, center regions) and applies different filtering operations to each zone. This segmentation allows the system to maintain simplicity through clear regional boundaries while achieving region-specific optimization for deep black and contrast preservation.
3Productivity
If representative brightness value is calculated without considering area non-uniformity, then calculation speed is improved, but dimming accuracy in irregular regions deteriorates
Solution Approach 1:
The patent incorporates block area information into the representative brightness value calculation specifically for regions with non-uniform illumination characteristics. Corner and edge blocks, which have different areas and illumination patterns compared to center blocks, receive area-compensated brightness calculations. This maintains calculation speed through efficient area-based adjustments while improving dimming accuracy in irregular regions.
Data Source
AI summary
According to an embodiment, a contrast and deep black can be enhanced by differentially performing spatial filtering according to a position of a block of a video image.