Projector Image Correction via Reference Pixel Projection

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Solution Overview

Problem

Existing image correction methods require projecting and photographing simple test patterns before content projection, making the process complex and susceptible to disruption from screen movement or illumination changes, necessitating frequent re-estimation.

Innovation Solution

A method and apparatus that project reference and counterbalance pixels in a raster scan mode to estimate and correct image distortion on projection surfaces without user notice, using synchronization between projection and photography units to model screen characteristics and apply correction information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If simple test patterns are projected and photographed for screen estimation, then screen characteristics can be modeled, but the correction process becomes complicated and content projection must be suspended

Engineering Contradiction:

Improvescreen estimation accuracyVSAvoidcorrection process complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs screen estimation by projecting test patterns and photographing them before actual content projection begins. This preliminary action captures screen characteristics (color, geometry) in advance, allowing the correction algorithm to be pre-computed and stored. When content is projected, the pre-computed correction is applied automatically without requiring repeated test patterns or suspending content projection.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system creates a digital model (copy) of the screen's characteristics by photographing test patterns and processing the images. This digital representation of screen properties is then used to generate correction matrices that are applied to content images, avoiding the need to physically modify the screen or repeatedly project test patterns during content playback.

Inventive Principle:

Principle #26Copying

2Reliability

If screen estimation is performed frequently to adapt to screen movement or illumination changes, then correction accuracy is maintained, but user experience deteriorates due to repeated interruption

Engineering Contradiction:

Improvecorrection accuracy under changing conditionsVSAvoiduser experience during content projection

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The system performs screen estimation periodically or at predetermined intervals rather than continuously or frequently. Test patterns are projected at specific moments (e.g., during natural pauses in content or at scheduled times), and correction parameters are updated accordingly. This periodic approach maintains correction accuracy while minimizing interruptions to content projection and user experience.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system uses feedback from photographing test patterns and analyzing screen characteristics to dynamically adjust correction parameters. The photographed test pattern images are processed to detect changes in screen color, geometry, or position, and correction matrices are regenerated based on this feedback. This allows the system to adapt to screen movement or illumination changes while controlling the frequency of interruptions.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If test patterns are projected for screen estimation, then distortion correction is possible, but the projection of desired content must be suspended

Engineering Contradiction:

Improvedistortion correction capabilityVSAvoidcontent projection interruption time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

Screen estimation and correction parameter computation are performed in advance before content projection begins. Test patterns are projected and photographed during setup or natural pauses, allowing the correction algorithm to be pre-computed. Once correction parameters are established, content projection proceeds continuously without interruption, as the correction is applied automatically using pre-computed matrices.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the timing of test pattern projection based on content playback state. Test patterns are projected during natural pauses, scene transitions, or at predetermined intervals rather than forcing interruptions during critical content moments. This dynamic scheduling minimizes perceived interruption while maintaining correction accuracy.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7813578B2Method and apparatus for unobtrusively correcting projected image

Publication Date: 2010.10.12 SAMSUNG ELECTRONICS CO LTD

AI summary

A method and apparatus are provided for unobtrusively estimating the characteristics of a projection surface, in order to correct the distortion of images resulting from the characteristics of the projection surface in the case of a projector. The method includes projecting at least one reference pixel and at least one counterbalance pixel corresponding to the reference pixel onto consecutive image frames, and correcting an image frame to be projected using correction information determined based on photographic information of the reference pixel.