Display Panel Moire Reduction via Spatial Frequency Filtering

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Solution Overview

Problem

Existing image quality adjustment methods for liquid crystal and organic EL panels face challenges in accurately correcting display unevenness due to moire interference, which occurs when the pixel pitch of the display panel differs from that of the CCD camera, leading to incomplete moire reduction.

Innovation Solution

An image quality adjustment system that includes a lighting controller to display a measurement image with selectively lit subpixels and a spatial frequency filter to remove moire components greater than or equal to half of the panel's spatial frequency from captured images, allowing for improved moire reduction without requiring precise alignment of the display panel and capture device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the pixel pitch of the display panel is different from the pixel pitch of the CCD camera, then the capture device can be used for measurement, but moire interference is generated in the captured image

Engineering Contradiction:

Improvecompatibility between capture device and display panelVSAvoidmoire interference

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the harmful moire spatial frequency components from the captured image through digital filtering. The correction table generation process identifies and eliminates the moire patterns that interfere with display unevenness measurement, allowing accurate correction despite pixel pitch mismatches between the capture device and display panel.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the spatial frequency parameters by applying a correction table that was generated using images with removed moire components. This correction table modifies the display data to compensate for display unevenness while avoiding the moire interference that would otherwise prevent accurate measurement and correction.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If a correction table is generated based on the captured image including moire, then the correction table can be created, but the display unevenness cannot be accurately corrected

Engineering Contradiction:

Improvecorrection table generationVSAvoiddisplay unevenness measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary processing step that generates a preliminary correction table based on captured images containing moire, then refines this correction table by removing moire-related spatial frequency components. This two-stage approach allows the system to work with practical captured images while achieving accurate display unevenness correction.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the display panel and capture device are disposed at a predetermined relative angle to reduce moire, then the moire can be shifted out of the display unevenness region, but strict management and precise alignment are required

Engineering Contradiction:

Improvemoire interferenceVSAvoidalignment and positioning requirements

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical alignment approach with a digital signal processing solution. Instead of requiring precise physical positioning of the capture device relative to the display panel, the system uses digital filtering to remove moire spatial frequency components from the captured image, eliminating the need for strict mechanical management and alignment procedures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively reduces moire interference in captured images, enabling more accurate correction of display unevenness and improving image quality by filtering out high-frequency components that contribute to moire, thus enhancing the image quality adjustment process.

Implementation Method 1

a first electric filter that removes at least a spatial frequency component greater than or equal to fd/2 from a first image obtained by capturing the measurement image displayed on the display panel using an capture device

Methodology Applied

Scientific EffectSpatial frequency filtering: Filter (electronic)

Implementation Method 2

the capture device includes an optical filter that removes a spatial frequency component greater than or equal to a half of a sampling frequency of the capture device

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentUS10735630B2Image quality adjustment device, image quality adjustment system and image quality adjustment method

Publication Date: 2020.08.04 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

AI summary

An image quality adjustment device includes: a lighting controller that controls a display panel including a plurality of pixels, each including arrangement of a plurality of subpixels such that the display panel displays a measurement image in which a part of the plurality of subpixels is lit; and a first electric filter that removes at least a spatial frequency component greater than or equal to fd/2 from a first image obtained by capturing the measurement image displayed on the display panel using an capture device when a panel spatial frequency determined by a pixel pitch of the pixel in a direction in which the plurality of subpixels are arrayed is set to fd.