Red Eye Detection Using Probability and Classification

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current methods for red eye correction in digital images often result in false positives due to the common occurrence of the color red and the difficulty in detecting non-frontal, rotated, or occluded faces, leading to suboptimal results and increased energy consumption with pre-flash hardware.

Innovation Solution

A system and method that includes a detection module assigning probabilities to pixels based on color, luminance, and circularity, followed by a classification module to distinguish between red eye, face, and background regions, allowing for a probabilistic correction that reduces false positives and eliminates the need for pre-flash hardware.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pre-flash hardware is used to constrict pupils and minimize red eye, then red eye prevention is improved, but energy consumption increases and shooting delay occurs

Engineering Contradiction:

Improvered eye preventionVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the mechanical pre-flash hardware system with a digital image processing system. The detection module analyzes the captured image to identify red eye regions based on color, position, and shape characteristics, then the correction module digitally modifies these regions to eliminate the red eye effect, substituting physical light emission with computational processing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs red eye detection and correction as a preliminary digital processing step after image capture. The detection module identifies potential red eye regions before final image processing, allowing for targeted correction without requiring preliminary physical intervention like pre-flashes.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If pre-flash hardware is used to constrict pupils and minimize red eye, then red eye prevention is improved, but shooting delay increases

Engineering Contradiction:

Improvered eye preventionVSAvoidshooting delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Inventive Principle:

Principle #10Preliminary action

3Extent of automation

If automated red eye detection based on color criteria is used, then operator involvement is reduced, but false positives increase

Engineering Contradiction:

Improveautomation levelVSAvoiddetection accuracy

Core Design Contradiction:

Extent of automationVSReliability

Solution Approach 1:

The patent segments the red eye detection process into multiple independent modules: a detection module that identifies candidate regions using color and position criteria, and a correction module that applies targeted corrections. This segmentation allows for more sophisticated multi-criteria analysis while maintaining full automation, reducing false positives by analyzing multiple features rather than relying on color alone.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes from single-parameter (color-based) detection to multi-parameter detection including color characteristics, position relative to face detected regions, and shape analysis. By considering multiple parameters simultaneously, the system achieves higher detection accuracy while maintaining automation, as the combination of criteria reduces false positives compared to color-only detection.

Inventive Principle:

Principle #35Parameter changes

4Measurement precision

If face detection is used to improve red eye detection accuracy, then detection precision is improved, but device complexity increases

Engineering Contradiction:

Improvered eye detection accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the face detection component serve multiple functions: it identifies face regions for context, locates eye positions, and provides spatial reference for red eye detection. By using the same face detection module for multiple purposes, the system improves red eye detection accuracy without proportionally increasing complexity, as the face detection infrastructure is already in place and is being leveraged for additional functionality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7567707B2Red eye detection and correction

Publication Date: 2009.07.28 III HOLDINGS 6 LLC

AI summary

A system suited to correction of red eyes in images includes a detection module which, for a plurality of pixels in a digital image, assigns a probability that a pixel is within a red eye. The probability has a value which may vary from a minimum value to maximum value. A classifier module classifies a patch of the image comprising a region of contiguous pixels which have at least a threshold probability that the pixel is within a red eye. The classifier module distinguishing patches which have a likelihood of including a red eye from other patches which have a likelihood of containing a face or background error rather than a redeye. A correction module assigns a correction to apply to pixels which are in a region of contiguous pixels having at least the threshold probability that the pixel is within a red eye and for which the associated patch has been identified by the classifier as having a probability of including a red eye.