Video Display Device Luminance Stretching Control
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Solution Overview
Problem
Conventional video display devices struggle to enhance display luminance effectively, leading to inconsistent image quality and contrast, as they rely on tone values rather than perceived luminance by the human eye, failing to specifically emphasize bright light-emitting parts.
Innovation Solution
A video display device with a control portion that detects light-emitting parts based on luminance features, such as histograms or maximum RGB values, to adjust backlight luminance and apply gain to the video signal, enhancing luminance only in the light-emitting areas while reducing it in non-emitting parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional enhancement function processes video signal based on maximum or minimum pixel values, then the signal range is widened and contrast feeling is increased, but the light-emitting parts are not specifically detected and emphasized, resulting in inconsistent image quality
Solution Approach 1:
The patent applies local quality by differentiating processing between light-emitting parts and non-light-emitting parts of the video signal. The control portion identifies light-emitting parts based on luminance distribution characteristics and applies enhancement processing specifically to these regions, rather than uniformly processing the entire video signal. This selective local processing ensures that light-emitting parts are emphasized while maintaining appropriate contrast in other areas.
Solution Approach 2:
The patent changes the parameter basis from simple maximum/minimum pixel values to luminance distribution characteristics including histogram analysis and standard deviation calculations. By using these refined parameters to identify light-emitting parts, the system achieves more accurate detection and enables targeted enhancement of specific regions with varying luminance properties.
2Device complexity
If enhancement function is applied uniformly to all video regions, then the processing is simple to implement, but the image quality is not consistently improved across different video content
Solution Approach 1:
The patent introduces multiple parameters including luminance histogram distribution, standard deviation of luminance values, and threshold-based classification to reliably identify light-emitting parts. These parameter changes enable consistent detection across diverse video content, improving image quality reliability without excessive complexity increase.
Solution Approach 2:
The patent segments the video signal processing into distinct stages: luminance histogram generation, light-emitting part detection based on distribution characteristics, and selective enhancement application. This segmentation allows the system to handle different video regions appropriately while maintaining manageable processing complexity through modular implementation.
3Illumination intensity
If the maximum value of tone is detected and gain is applied to expand high tone regions, then the contrast feeling is increased, but the minimum value detection and compression gain application may reduce quality in dark regions
Solution Approach 1:
The patent applies local quality by making the enhancement and compression gains dependent on the detected light-emitting part characteristics. Different gain values are applied to different regions: expansion gain for light-emitting parts and compression gain for non-light-emitting parts. This localized approach prevents quality degradation in dark regions while enhancing brightness where needed.
Solution Approach 2:
The patent applies partial action by selectively applying enhancement only to detected light-emitting parts rather than uniformly processing the entire video signal. The control portion determines appropriate gain application based on luminance distribution analysis, applying expansion or compression gains only where necessary to maintain or improve image quality in specific regions.
Data Source
AI summary
A video display device increases a feeling of brightness and expresses a video with high contrast by detecting a part of a video signal that emits light, enhancing the display luminance of the light-emitting part, and displaying the part. A light emission detection portion (1) uses a prescribed feature quantity related to the brightness of an input video signal, predetermines the light emission quantity for the video signal on the basis of the relationship with the feature quantity, and detects the light emission quantity for each input video signal frame from the feature quantity. A backlight luminance stretch portion (3) stretches the light source luminance of the backlight according to the light emission quantity detected. A video signal luminance stretch portion (6) stretches the video signal according to the light emission quantity or the luminance distribution of the input video signal.