Display Controller High-Low Frequency Signal Segmentation
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Solution Overview
Problem
Existing display device technologies face challenges in reducing inter-frame noise while avoiding afterimages on motion images, particularly in regions with edges or textures, and in preventing noise amplification at these areas.
Innovation Solution
A display device and method that involve generating a first and second sub-frame image signal by processing a frame image signal to separate high and low frequency components, using an excess signal generator to adjust grayscale values, and applying correction signals based on contrast and flatness calculations to output the sub-frame signals, thereby reducing noise and preventing flicker and clip phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise reduction is performed based on flatness calculated from image signal, then inter-frame noise and imaging noise are reduced, but afterimage is generated on motion images
Solution Approach 1:
The image signal is segmented into high-frequency components and low-frequency components. The high-frequency component processing is selectively applied based on grayscale value thresholds, while low-frequency components are processed separately. This segmentation allows noise reduction to be applied only where appropriate, preventing afterimage generation in motion regions while maintaining noise reduction effectiveness in static regions.
Solution Approach 2:
Different processing strategies are applied to different regions of the image based on local characteristics. Regions with grayscale values below the threshold receive high-frequency noise reduction processing, while regions above the threshold (typically motion regions) receive different processing to avoid afterimage. This local quality approach ensures that noise reduction is applied selectively without causing unwanted side effects in specific areas.
2Object-affected harmful factors
If motion adaptive processing is performed on stop region with fixed feedback coefficient, then noise reduction is achieved, but inter-frame noise amplitude increases at edge or texture regions
Solution Approach 1:
The feedback coefficient is made dynamic rather than fixed. The coefficient varies based on the grayscale value of the image signal, allowing the processing to adapt to different regions. In edge or texture regions with higher grayscale values, the processing parameters are adjusted to prevent noise amplification, while in flat regions with lower grayscale values, aggressive noise reduction can be applied.
Solution Approach 2:
The processing parameters including feedback coefficient and threshold values are changed based on the local characteristics of the image signal. By monitoring grayscale values and adjusting parameters dynamically, the system prevents inter-frame noise amplification in edge regions while maintaining effective noise reduction in flat regions. This parameter adaptation resolves the contradiction between noise reduction and noise amplification.
Data Source
AI summary
A display device includes a controller that generates first and second sub-frame image signals based on a frame image signal. The first and second sub-frame image signals respectively correspond to sub-frames. The controller includes a filter, a signal generator, and a signal output. The filter outputs a high frequency image signal, obtained by increasing a high frequency component in the frame image signal, and a low frequency image signal obtained by decreasing the high frequency component in the frame image signal. The signal generator generates an excess signal from a portion of the high frequency image signal having a grayscale value equal to or greater than a maximum allowable grayscale value. The signal output selectively outputs the first sub-frame image signal based on the excess signal and the high frequency image signal and the second sub-frame image signal based on the excess signal and the low frequency image signal.