Automatic Red Eye Removal Using Weighted Color Analysis

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Solution Overview

Problem

Existing methods for red eye removal in photographs require user intervention or have high computational complexity, and existing automated methods do not effectively distinguish between red eye regions and other image features.

Innovation Solution

A method that calculates weighted red values for each pixel using specific weightings for red, green, and blue color values and luminance, automatically selects red eye pixels, and corrects them by grouping contiguous pixels into regions, rejecting non-round pupils, regions too close to others, and those not proximate to facial or sclera features, ultimately replacing red eye pixels with black.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If automated red eye removal software is used, then user intervention is reduced, but computational complexity increases

Engineering Contradiction:
Improveuser intervention requirementVSAvoidcomputational complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The red eye removal process is divided into distinct stages: candidate region identification using color constraints, shape-based filtering to eliminate non-pupil candidates, and final verification. This segmentation allows each stage to focus on specific computational tasks, reducing overall complexity while maintaining automation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The algorithm applies different processing strategies to different regions of the image. Candidate pixels are identified using local color properties (red dominance), then shape constraints are applied locally to each candidate region. This localized approach reduces computational complexity by avoiding global image analysis while maintaining effective red eye detection.

Inventive Principle:
Principle #3Local quality

2Productivity

If simple color-based detection is used, then processing speed increases, but accuracy in distinguishing red eye from other features decreases

Engineering Contradiction:
Improveprocessing speedVSAvoidred eye detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The detection process is segmented into multiple filtering stages. First, pixels are identified as candidates based on simple color constraints (red dominance). Then, shape constraints are applied to filter candidates. Finally, additional criteria eliminate false positives. This multi-stage segmentation maintains processing speed while progressively improving detection accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The algorithm uses multiple parameter thresholds to distinguish red eye from other features. Color constraints check for red dominance with specific threshold values. Shape constraints evaluate aspect ratio and circularity with defined thresholds. These parameter changes at different stages enable accurate discrimination while maintaining efficient processing.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If multiple processing stages are applied, then red eye detection accuracy improves, but computational complexity increases

Engineering Contradiction:
Improvered eye detection accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The processing is divided into sequential stages with clear input-output relationships. Stage 1 identifies candidate pixels using color constraints. Stage 2 groups candidates into regions and applies shape constraints. Stage 3 applies additional filtering criteria. Each stage builds on previous results, improving accuracy while keeping individual stage complexity manageable through the segmentation structure.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS7852377B2Automatic red eye removal
Publication Date: 2010.12.14 ARCSOFT INC
  • US7852377B2 patent drawing
  • US7852377B2 patent drawing
  • US7852377B2 patent drawing

AI summary

A method for removing a red eye from an image includes (1) calculating a weighted red value for each pixel in the image from red, green, and blue color values and a luminance value of each pixel in the image, (2) selecting a plurality of pixels in the image having weighted red values greater than a threshold as red eye pixels, and (3) correcting some of the red eye pixels to remove the red eye from the image. The weighted red value for a pixel is calculated as follows:f=c1⁢r+c2⁢g+c3⁢bY,wherein f is the weighted red value, r is the red color value, g is the green color value, b is the blue color value, c1 is a first weight given to the red color value, c2 is a second weigh given to the green color value, c3 is a third weight given to the blue color value, and Y is the luminance.