Echo Compensation for Stereoscopic Video Cross-talk

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Solution Overview

Problem

Field-sequential stereoscopic display methods, particularly using LCD shutter glasses, suffer from image cross-talk due to slow response times in liquid crystal displays and phosphor lag in plasma display panels, leading to ghost images and reduced depth perception.

Innovation Solution

A method for processing video data that calculates and subtracts echo images from subsequent frames, adapting to image content and using a tilt function to manage brightness, ensuring effective echo cancellation without reducing overall image quality or brightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If field-sequential stereoscopic display method is used, then compatibility between 2D and 3D modes is improved, but image cross-talk increases due to slow response time

Engineering Contradiction:
Improvecompatibility between 2D and 3D modesVSAvoidimage cross-talk
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by calculating and subtracting echo images from the current frame before display. The echo compensation process predicts ghost images based on previous frame information and removes them in advance, preventing cross-talk rather than correcting it after it occurs. This is implemented through the echo compensation unit that processes each frame before it is sent to the display device.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using information from previously displayed frames to compensate for echo effects in the current frame. The echo compensation unit continuously receives feedback about display response characteristics and adjusts the echo subtraction process accordingly, creating a closed-loop system that adapts to the display device's temporal response behavior.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If echo compensation is applied, then ghost images are reduced, but image brightness may be reduced

Engineering Contradiction:
Improveghost imagesVSAvoidimage brightness
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The patent applies local quality by selectively applying echo compensation only where needed. The tilt function modifies the echo subtraction process to preserve brightness in low-contrast regions while maintaining ghost image reduction in high-contrast areas. This localized approach ensures that echo compensation does not uniformly reduce image brightness across all regions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses parameter changes by dynamically adjusting the tilt parameter based on image content characteristics. The tilt function modifies the echo compensation strength according to local image properties, changing parameters adaptively to maintain both ghost image reduction and brightness preservation depending on the specific region being processed.

Inventive Principle:
Principle #35Parameter changes

3Speed

If LCD shutter glasses are used, then switching speed is improved, but extinction ratio decreases leading to reduced brightness

Engineering Contradiction:
Improveswitching speedVSAvoidimage brightness
Core Design Contradiction:
SpeedVSIllumination intensity

Solution Approach 1:

The patent converts the harmful effect of slow display response and resulting echo into a benefit by using echo compensation. Instead of viewing the display's temporal response characteristics as purely detrimental, the system utilizes this predictable echo behavior to pre-calculate and remove ghost images, turning the display's inherent limitation into a manageable parameter for compensation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP2521358B1Image Cross-talk Cancellation in Stereoscopic Video Display Devices
Publication Date: 2016.09.14 C R S IIMOTION
  • EP2521358B1 patent drawingFigure 1
  • EP2521358B1 patent drawingFigure 2
  • EP2521358B1 patent drawingFigure 3~4

AI summary

A method for processing video data comprising a sequence of successive image frames is disclosed. In accordance with one example of the invention the method comprises: receiving an image frame from a video data source; calculating a first echo image based on the image frame; providing a second echo image based on a further image frame preceding the image frame; calculating an echo compensated image frame by subtracting the difference of the echo images from the image frame.