Subpixel Rendering Filter Switching for Display Color Balance

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Solution Overview

Problem

Display systems with 2D high-brightness sub-pixel layouts face challenges in maintaining color balance at the edges, particularly when using subpixel rendering modes like MLS, which can introduce color balance errors, such as perceiving white lines as bluish or yellowish due to incorrect subpixel activation.

Innovation Solution

An image processing method that detects specific image features causing color balance errors and switches between subpixel rendering filters, specifically using SCS mode for affected subpixels at the edges to maintain color balance while retaining the sharpness benefits of MLS mode for other areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If MLS subpixel rendering mode is used for high brightness display, then luminance and sharpness are improved, but color balance accuracy deteriorates at image edges

Engineering Contradiction:
ImproveluminanceVSAvoidcolor balance accuracy
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent applies different subpixel rendering strategies to different regions of the display. MLS mode is used for central regions where sharpness is prioritized, while SCS mode is used for edge regions where color balance accuracy is critical. This spatial differentiation of processing quality resolves the contradiction by allowing each region to be optimized for its specific requirements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent dynamically selects between MLS and SCS rendering modes based on spatial position and image content characteristics. The rendering mode is not fixed but adapts locally according to whether a pixel is in a central or edge region, and whether it represents a high-frequency or low-frequency image feature. This dynamic adaptation allows the system to maximize luminance where needed while preserving color balance where critical.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If SCS subpixel rendering mode is used for color balance accuracy, then color representation is improved, but image sharpness deteriorates

Engineering Contradiction:
Improvecolor balance accuracyVSAvoidimage sharpness
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

SCS mode is applied locally to edge regions and low-frequency areas where color balance is more important than sharpness, while MLS mode is applied to central regions and high-frequency areas where sharpness is prioritized. This selective application resolves the contradiction by matching the rendering mode to the local image characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The display image is segmented into different regions (central vs. edge, high-frequency vs. low-frequency) that are processed with different rendering modes. This segmentation allows SCS to be used where color balance matters most without sacrificing overall image sharpness, as MLS handles the regions where sharpness is critical.

Inventive Principle:
Principle #1Segmentation

3Illumination intensity

If 2D high-brightness subpixel layout is used, then luminance output is improved, but color balance stability deteriorates at panel edges

Engineering Contradiction:
Improveluminance outputVSAvoidcolor balance stability
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent recognizes that edge regions of 2D subpixel layouts have different color balance characteristics than central regions. By applying SCS mode specifically to edge subpixels, the system compensates for the layout-induced color balance instability at edges while maintaining the high luminance output benefits of the 2D arrangement throughout the entire display.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent preemptively applies different rendering modes to different spatial regions to counteract the known color balance instability that occurs at panel edges in 2D layouts. By anticipating the color balance issues at edges and applying SCS mode in advance, the system prevents rather than corrects the color balance degradation.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP2147426B1Image color balance adjustment for display panels with 2d subpixel layouts
Publication Date: 2015.07.29 SAMSUNG DISPLAY CO LTD
  • EP2147426B1 patent drawingFigure 1
  • EP2147426B1 patent drawingFigure 2~3
  • EP2147426B1 patent drawingFigure 4

AI summary

The subpixel rendering component of a display system provides the capability to substitute a second subpixel rendering filter for a first subpixel rendering filter for computing the values of certain subpixels on the display panel when the input image data being rendered indicates an image feature that may give rise to a color balance error at some portion of the displayed output image. An image processing method of correcting for color balance errors detects the location of a subpixel being rendered, and for certain subpixels, detects whether the input image data indicates the presence of a particular image feature. When the image feature is detected for particular subpixels being processed, a second subpixel rendering image filter is substituted for a first subpixel rendering image filter.