Backlight Local Dimming Image Compensation for Flicker and Power
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Solution Overview
Problem
Current backlight local dimming systems face issues with image quality due to inappropriate backlight decisions and lack of effective image compensation, leading to problems like color washout, ripples, and flickers, while also consuming high power.
Innovation Solution
A method and apparatus that divide the image into blocks, calculate average and maximum values, generate adaptive backlight control signals, and use temporal filtering to produce a compensated image, reducing computation and hardware requirements while improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If backlight local dimming is applied to reduce power consumption, then power consumption is reduced, but image quality deteriorates due to color washout, ripples, and flickers
Solution Approach 1:
The image is divided into multiple image blocks, each corresponding to a backlight source. This segmentation allows independent control of each backlight source based on the content of its corresponding image block, enabling precise local dimming while maintaining overall image quality. The segmentation prevents the ripple effect by ensuring that dimming decisions are made at the block level rather than affecting entire regions.
Solution Approach 2:
The patent performs preliminary calculations of average and maximum values for each image block before generating backlight control signals. This preliminary action allows the system to pre-determine which blocks require dimming and by how much, enabling smooth transitions and preventing flicker by preparing compensation data in advance rather than reacting to changes in real-time.
Solution Approach 3:
The patent implements an image compensation process that uses feedback from the calculated average and maximum values to adjust the backlight control signals. The compensation process analyzes the relationship between these values and dynamically adjusts dimming levels to prevent color washout and maintain image quality, creating a closed-loop control system that continuously optimizes both power consumption and image quality.
2Reliability
If complex image compensation is performed to maintain image quality, then image quality is improved, but device complexity and computation increase
Solution Approach 1:
By segmenting the image into blocks and processing each block independently with simple average and maximum value calculations, the patent avoids the need for complex global image processing algorithms. This segmentation reduces computational complexity while maintaining image quality through localized control.
Solution Approach 2:
The patent focuses on calculating and comparing only two key parameters (average and maximum values) for each image block, rather than performing complex multi-parameter analysis. This parameter simplification reduces computational requirements and hardware complexity while still providing sufficient information for effective backlight control and image quality maintenance.
3Reliability
If more backlight sources are used to improve image quality and brightness, then image quality is improved, but power consumption increases
Solution Approach 1:
The patent applies local quality control by allowing different backlight sources to operate at different brightness levels based on the specific content of their corresponding image blocks. Bright areas receive full or near-full brightness while dark areas are dimmed, optimizing power consumption locally without compromising overall image quality. This local quality approach ensures that each region receives the appropriate amount of light for its content.
Solution Approach 2:
The patent implements dynamic backlight control where the brightness of each backlight source is adjusted in real-time based on the average and maximum values of its corresponding image block. This dynamic adjustment allows the system to adapt to changing image content, maintaining high image quality when needed while reducing power consumption during dark scenes or when using dark frames.
Data Source
AI summary
An apparatus compensates image in a backlight local dimming system for estimating pixels of the image after backlight spreading of a plurality of backlight sources in the backlight local dimming system. The apparatus includes a block dimming value decision unit, a quality/power-saving priority decision unit, a temporal filter, a backlight spread approximation unit, and an image compensation unit. The block dimming value decision unit calculates an average value, a maximum value and a initial value for each image block. The quality/power-saving priority decision unit generates a backlight control signal based on the average value, the initial value, and two thresholds. The temporal filter adaptively generates a backlight pulse width modulation signal based on the backlight control signal. The backlight spread approximation unit generates a backlight spread image based on the backlight pulse width modulation signal. The image compensation unit compensates the image based on the backlight spread image.