Direct Backlight Brightness Adjustment for Abrupt Gray Level Variations
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Solution Overview
Problem
Existing local backlight adjusting methods for direct backlight in LCDs struggle with displaying images containing abrupt gray level variations, leading to issues like clipping and edge breakage due to inconsistent brightness adjustments across sub-regions.
Innovation Solution
Perform edge detection to identify sensitive zones with significant gray level differences and adjust backlight brightness separately for these zones and adjacent regions, using clipping preprocessing to maintain consistent adjustments and prevent overcompensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If local backlight brightness adjustment is performed based on average gray level of pixels in each sub-region, then power consumption is reduced and display quality is improved, but clipping and edge breakage occur when gray level abruptly varies
Solution Approach 1:
The patent segments the backlight region into multiple sub-regions corresponding to different backlight LED groups, and further segments the image processing into two stages: first processing non-sensitive zones using average gray level, and second processing sensitive zones with edge detection. This segmentation allows different processing methods to be applied to different regions, resolving the contradiction between power saving and display quality.
Solution Approach 2:
The patent applies different processing strategies to different regions: for non-sensitive zones, it uses average gray level adjustment for power saving; for sensitive zones with abrupt gray level changes, it uses edge detection and uniform adjustment to preserve display quality. This local differentiation resolves the contradiction by tailoring processing methods to regional characteristics.
2Device complexity
If uniform backlight brightness adjustment is applied across the entire backlight region, then processing complexity is reduced, but edge breakage and clipping occur at gray level boundaries
Solution Approach 1:
The patent segments the backlight region into multiple sub-regions and identifies sensitive zones with abrupt gray level changes. By segmenting the processing into two stages (non-sensitive zone processing and sensitive zone processing), the system achieves region-specific adjustments that prevent edge breakage while maintaining manageable processing complexity.
Solution Approach 2:
The patent performs edge detection and identifies sensitive zones before applying the uniform adjustment. This preliminary action allows the system to prepare appropriate adjustment strategies in advance for regions that would otherwise cause edge breakage, resolving the contradiction between processing simplicity and display quality.
3Loss of energy
If backlight brightness is adjusted according to low average gray level images, then power consumption is reduced, but the image requires considerable compensation and color errors occur
Solution Approach 1:
The patent applies different processing strategies to different regions: for non-sensitive zones with low average gray level, it uses average gray level adjustment for power saving; for sensitive zones with abrupt changes, it uses edge detection and uniform adjustment to preserve color accuracy. This local differentiation resolves the contradiction between power saving and color accuracy.
Solution Approach 2:
The patent uses edge detection to identify sensitive zones and adjusts the processing strategy based on this feedback. When abrupt gray level changes are detected, the system switches to uniform adjustment mode to prevent color errors, thereby maintaining color accuracy while still achieving power savings in appropriate regions.
Data Source
AI summary
The present invention discloses a local backlight brightness adjustment method for a direct backlight in a display device, the method comprising the steps of: step 1: performing edge detection on an input image to determine whether a sensitive zone exists, the sensitive zone being a portion in the input image in which a gray level difference between adjacent pixels is greater than a predetermined threshold; and Step 2: if a sensitive zone exists, performing a backlight brightness adjustment with respect to a backlight region corresponding to the sensitive zone and a remaining backlight region other than the backlight region corresponding to the sensitive zone, respectively. According to the above-mentioned technical solution, since the backlight brightness adjustment are performed with respect to the backlight region corresponding to the sensitive zone and the remaining backlight region other than the backlight region corresponding to the sensitive zone, respectively, thus, when there is gray level abruptly-varying portion in the image, the display performance of the displayer can still be ensured.