Adaptive Chrominance Filtering for Display Pixel Signal Processing

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Solution Overview

Problem

High-resolution displays with small pixel pitches face challenges in maintaining brightness and power efficiency due to reduced aperture, and existing sub-pixel sampling methods can lead to loss of chrominance resolution and color accuracy, especially in graphics and high-chrominance content.

Innovation Solution

A method that adaptively low-pass filters input signals based on chrominance variation between adjacent pixels to reduce chrominance resolution to match the display's capabilities, while maintaining luminance resolution, using a processing system that determines chrominance variation and applies filtering only where necessary to prevent color errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the pixel pitch is reduced to increase display resolution, then the display resolution is improved, but the aperture of sub-pixels decreases leading to reduced brightness and increased power consumption

Engineering Contradiction:
Improvedisplay resolutionVSAvoidbrightness
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The invention segments the chrominance information processing by applying low-pass filtering selectively to chrominance components (Cb and Cr in YCbCr color space) while preserving luminance components. This segmentation allows independent optimization of resolution and brightness characteristics.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different processing quality to different components: full resolution is maintained for luminance (brightness) components while reduced resolution is applied to chrominance (color) components. This local quality differentiation resolves the contradiction by preserving brightness perception while reducing color information that would otherwise require more bandwidth.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If sub-pixel sampling is used to reduce the number of sub-pixels, then the perceived resolution is maintained, but chrominance resolution is lost leading to color errors in high-chrominance content

Engineering Contradiction:
Improveperceived resolutionVSAvoidchrominance resolution
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent performs preliminary low-pass filtering on chrominance components before sub-pixel sampling to prevent aliasing and color errors. By pre-processing the chrominance information to remove high-frequency components that would cause errors, the system maintains color accuracy while still benefiting from reduced sub-pixel requirements.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention introduces an intermediary processing step that converts RGB input to YCbCr color space, allowing separate handling of luminance (Y) and chrominance (Cb, Cr) components. This intermediary representation enables selective processing where luminance maintains full resolution for perceived sharpness while chrominance is filtered to prevent color errors.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Illumination intensity

If the aperture of sub-pixels is increased to improve brightness, then the brightness is improved, but the display resolution must be reduced

Engineering Contradiction:
ImprovebrightnessVSAvoiddisplay resolution
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent changes the parameter representation of color information by transforming from RGB to YCbCr color space. This parameter transformation separates brightness (luminance Y) from color (chrominance Cb, Cr), allowing independent optimization where luminance can be maintained at high resolution while chrominance is reduced without significantly impacting perceived image quality.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1949352B1A method and apparatus processing pixel signals for driving a display and a display using the same
Publication Date: 2013.10.16 INNOLUX CORP
  • EP1949352B1 patent drawingFigure 1
  • EP1949352B1 patent drawingFigure 2
  • EP1949352B1 patent drawingFigure 3

AI summary

A method of processing image data comprises receiving input signals for specifying red, green and blue colours of the pixels of a display, performing a per-pixel low pass filtering (40) of the input signals, the low pass filtering function being dependent on the chrominance variation between adjacent pixels, and providing the filtered output signals for use in driving the pixels of a display. This method essentially measures the chrominance variation of the incoming signal, in the form of the colour change frequency, and depending on this variation, adaptively low-pass filters the incoming signal. This can be in such a way that the chrominance resolution of the outgoing signal is below the maximum chrominance resolution of the intended display, without errors in the average colour of a small group of pixels.