Eye Openness Detection Using Pixel Intensity Thresholds

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Solution Overview

Problem

Existing eye tracking systems in wearable devices face challenges in accurately determining eye openness and positioning lenses for optimal viewing, especially in varying eye shapes and sizes, which affects the immersive experience in VR and AR applications.

Innovation Solution

The system employs an eye tracking device with an image sensor and infrared illuminator to capture images of the eye, analyzing pixel intensity and reflection patterns to determine eye openness and adjust lens positioning based on threshold values, ensuring the eye is optimally aligned with the lens for improved immersion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing eye tracking systems use standard image processing methods to determine eye openness, then the system structure remains simple, but measurement precision deteriorates due to varying eye shapes and sizes

Engineering Contradiction:
Improveeye openness detection accuracyVSAvoidimage processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transforms the eye openness detection problem from direct pixel intensity analysis to a parameter-based approach. It extracts geometric parameters (eye contour, pupil position, eyelid boundaries) and uses normalized coordinate systems to account for varying eye shapes and sizes. This parameter transformation enables accurate measurement across different users without requiring complex adaptive algorithms for each individual case.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system performs preliminary actions by pre-defining anatomical reference points and standardization procedures for eye structure analysis. It establishes baseline parameters for eye contours, pupil positions, and eyelid boundaries before actual measurement, allowing the system to adapt to different eye geometries using standardized transformation routines rather than requiring complex real-time adaptation.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the system uses detailed image analysis to accurately determine eye position and openness, then measurement precision improves, but processing time increases

Engineering Contradiction:
Improveeye position detection accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the eye image analysis into distinct functional regions: outer eye contour detection, pupil boundary identification, and eyelid position determination. Each segment is processed independently using optimized algorithms appropriate for that specific feature, reducing overall processing time compared to analyzing the entire image uniformly. The segmentation allows parallel processing of different eye features.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system extracts only the essential geometric features needed for eye tracking (contour points, pupil center, eyelid boundaries) from the full eye image, discarding redundant information. This extraction approach focuses computational resources on critical measurement points rather than processing every pixel, significantly reducing processing time while maintaining measurement precision.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If the system implements comprehensive eye tracking analysis to ensure optimal lens alignment, then the immersive experience improves, but device complexity increases

Engineering Contradiction:
Improveaccommodation of different eye shapesVSAvoidprocessing system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal eye analysis framework that handles various eye shapes, sizes, and anatomical variations through standardized geometric modeling. The same core algorithms and parameter extraction methods work across different users and eye types, providing multi-functional adaptability without requiring separate specialized processing paths for each eye geometry type.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses parameter transformation and normalization to adapt to different eye geometries. By expressing eye features in normalized coordinate systems and using scaling factors, the system maintains consistent processing logic across diverse eye shapes and sizes, achieving versatility through mathematical parameter adjustments rather than structural system changes.

Inventive Principle:
Principle #35Parameter changes

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 provides accurate eye openness detection and adjusts lens positioning, enhancing the immersive experience by ensuring optimal eye-lens alignment, accommodating different eye shapes and sizes, and improving the overall performance of VR and AR applications.

Implementation Method 1

an eye tracking device with an image sensor and infrared illuminator to capture images of the eye

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

image sensor and infrared illuminator to capture images

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP4014835B1Determining eye openness with an eye tracking device
Publication Date: 2024.07.24 TOBII TECH AB
  • EP4014835B1 patent drawingFigure 1
  • EP4014835B1 patent drawingFigure 1A
  • EP4014835B1 patent drawingFigure 2

AI summary

A method for determining eye openness with an eye tracking device is disclosed. The method may include determining, for pixels of an image sensor of an eye tracking device, during a first time period when an eye of a user is open, a first sum of intensity of the pixels. The method may also include determining, during a second time period when the eye of the user is closed, a second sum of intensity of the pixels. The method may further include determining, during a third time period, a third sum of intensity of the pixels. The method may additionally include determining that upon the third sum exceeding a fourth sum of the first sum plus a threshold amount, that the eye of the user is closed, the threshold amount is equal to a product of a threshold fraction and a difference between the first sum and the second sum.