Display Luminance Control via Spatial Tone Mapping for Light Leakage
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Solution Overview
Problem
Existing display devices suffer from light leakage, which results in reduced contrast and darker-than-intended display effects due to the inability of pixels to completely obscure backlight light, especially in dark regions, leading to suboptimal display quality.
Innovation Solution
A method and system that adjust display luminance and apply a spatially-variant tone mapping operation based on image data features to reduce light leakage and enhance contrast, using a display controller with a luminance adjustment unit and tone mapping module to optimize display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If local dimming is used to reduce light leakage, then contrast is improved, but device complexity increases
Solution Approach 1:
The patent applies global luminance adjustment rather than local dimming, changing the control parameter from spatially-variant to uniformly-applied. This simplifies the backlight system while maintaining improved display quality through tone mapping operations that compensate for the global luminance reduction in dark regions.
Solution Approach 2:
The patent extracts the light leakage problem from the local region and addresses it globally by reducing overall luminance in dark regions. Instead of modifying individual backlight zones, the solution removes excess luminance across the entire display when displaying dark content, thereby simplifying the backlight structure while still eliminating light leakage artifacts.
2Ease of manufacture
If global luminance reduction is applied to reduce light leakage, then contrast is improved, but detail visibility in dark regions deteriorates
Solution Approach 1:
The patent applies tone mapping operations before display to pre-process the image data and preserve detail information in dark regions. By performing this luminance redistribution in advance, the system ensures that when global luminance is reduced to eliminate light leakage, the important detail information remains visible through the tone-mapped image data.
Solution Approach 2:
The tone mapping operation acts as an intermediary between the original image data and the final display output. It mediates the conflict between global luminance reduction and detail preservation by transforming the image data to maintain visible detail while accommodating the reduced luminance environment, thus preventing information loss.
3Object-affected harmful factors
If locally-adjusted backlight is used to match image regions, then light leakage is reduced, but device complexity and manufacturing cost increase
Solution Approach 1:
Instead of adapting the backlight to match the image content (complex approach), the patent inverts the approach by adapting the image processing (tone mapping) to work with a simpler global luminance adjustment. This reverses the traditional problem-solving direction, achieving light leakage reduction through image space manipulation rather than physical backlight complexity.
Solution Approach 2:
The patent replaces the mechanical/optical complexity of locally-adjusted backlight systems with a computational approach using tone mapping operations. Instead of physically configuring multiple backlight zones to match image regions, the system uses software-based luminance adjustment and tone mapping to achieve the same visual effect with simpler hardware.
Data Source
AI summary
A method of controlling display of image data representing an image on a display device. The method includes determining one or more features of the image data. The method includes, in dependence on the determining, adjusting a display luminance of the display device, and applying a spatially-variant tone mapping operation to the image data. A display system and a display controller for controlling display of image data representing an image on a display device.