Global Backlight Adjustment for Local-Dimming Halo Correction
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Solution Overview
Problem
Conventional local-dimming technologies in display panels suffer from issues such as backlight halo and checkerboard-type halos, particularly in dark-field images, due to uneven backlight brightness.
Innovation Solution
A method and circuit system for correcting local-dimming parameters through global backlight adjustment, which involves detecting regions with dark-field halo, calculating a quantity ratio, and performing global backlight adjustment when necessary to reduce halos and enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional local-dimming technology is applied to divide image into M*N regions and perform different backlight controls on different regions, then contrast is increased and power consumption is saved, but backlight halo and checkerboard-type halo occur in dark field regions
Solution Approach 1:
The patent combines global backlight adjustment with local dimming control. Instead of relying solely on regional backlight control, it integrates a global adjustment mechanism that uniformly modulates backlight across all regions when dark-field halo is detected, merging global and local control strategies to eliminate halo while preserving contrast enhancement benefits
Solution Approach 2:
The patent dynamically changes the backlight control parameter from purely local regional control to a hybrid approach incorporating global adjustment. When dark-field halo conditions are detected (through pixel value analysis and ratio calculation), the system switches to global backlight adjustment mode, changing the control parameter strategy to eliminate halo artifacts
2Use of energy by moving object
If local dimming is performed by driving lower backlight value to brighter regions with data compensation, then power consumption is saved, but uneven local brightness and dark-field halo occur
Solution Approach 1:
The patent implements a dynamic backlight control system that adaptively switches between pure local dimming mode and hybrid global-adjustment mode based on real-time image content analysis. The system continuously monitors pixel values and halo occurrence ratios, dynamically adjusting the control strategy to maintain brightness uniformity while preserving power-saving benefits
Solution Approach 2:
The patent introduces a feedback mechanism that analyzes pixel values in each region, calculates the ratio of dark-field halo regions to total regions, and uses this feedback to determine whether to activate global backlight adjustment. This closed-loop feedback ensures brightness uniformity is maintained while minimizing unnecessary power consumption
Data Source
AI summary
A method for correcting local-dimming parameters through global backlight adjustment and a circuit system are provided. The circuit system connects with a backlight control circuit of a display. In the method operated in the circuit system, when an image is received, the pixel values of each of the regions divided from the image can be counted so as to obtain a local maximum and a local average of every region, and a global average of the image. The region having a dark-field halo can be detected based on a local difference between the local maximum and the local average. A leakage level can be obtained by determining an impact of the dark-field halo on the whole image based on a threshold. The leakage level and the global average are referred to for calculating a gain for global backlight adjustment after performing local dimming.