Eye Tracking Light Modulation for Varying Illumination

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Solution Overview

Problem

Eye tracking technologies face challenges in accurately determining user gaze due to poor image quality, particularly in varying lighting conditions, where automatic exposure adjustments can reduce image quality and lead to erroneous detection, and active illumination can consume excessive battery life.

Innovation Solution

An algorithm adjusts camera attributes such as exposure time, gain, and light intensity based on facial features, ambient light, and contrast levels to optimize image quality and reduce energy consumption by varying the intensity of infrared light sources according to the specific requirements of the image capture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If automatic exposure adjustments are made to improve overall image quality, then general image quality improves, but eye tracking image quality deteriorates

Engineering Contradiction:
Improveimage qualityVSAvoideye tracking accuracy
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent applies local quality by implementing region-specific exposure control where different exposure parameters are applied to different regions of the image sensor. The eye tracking region receives optimized exposure settings tailored for high-contrast facial features, while other regions use standard automatic exposure adjustments. This resolves the contradiction by allowing simultaneous optimization for both general image quality and eye tracking precision in their respective regions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the image processing into separate pathways: one for general image capture with automatic exposure and another for eye tracking with dedicated exposure control. By dividing the image sensor output into regions of interest (eye tracking region) and non-interest regions, the system can apply different processing strategies to each segment, thereby maintaining eye tracking accuracy while still performing overall exposure adjustments.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If active illumination is increased to improve image quality in low light, then image quality improves, but battery consumption increases

Engineering Contradiction:
Improveimage qualityVSAvoidbattery consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic illumination control where the active light source intensity is continuously adjusted based on real-time assessment of ambient lighting conditions and detected image quality metrics. The system transitions between different illumination states (off, low, medium, high intensity) depending on whether the environment is well-lit, dim, or dark, thereby optimizing the balance between image quality and battery consumption rather than maintaining a fixed high illumination level.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the illumination parameter (light intensity) dynamically based on environmental conditions. The system monitors ambient light levels and adjusts the active illumination source intensity accordingly, using higher intensity only when necessary for image quality and reducing or turning off illumination when ambient light is sufficient, thus resolving the contradiction between image quality and energy consumption.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If exposure time is increased to improve image quality, then image quality improves, but motion blur increases

Engineering Contradiction:
Improveimage qualityVSAvoidimage sharpness
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies dynamic exposure time adjustment where the exposure duration is continuously optimized based on detected scene characteristics, ambient light levels, and motion detection. The system adapts exposure time in real-time, using longer exposures only when the scene is static and well-lit, and shorter exposures when motion is detected or lighting is poor, thereby balancing image quality and sharpness requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements periodic reassessment of exposure parameters during image capture sequences. The system continuously evaluates image quality metrics and motion detection results, adjusting exposure time in periodic intervals to maintain optimal settings. This periodic optimization allows the system to capture high-quality images with appropriate exposure times while minimizing motion blur through timely parameter adjustments.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentUS9836639B2Systems and methods of light modulation in eye tracking devices
Publication Date: 2017.12.05 META PLATFORMS TECHNOLOGIES LLC
  • US9836639B2 patent drawing
  • US9836639B2 patent drawing
  • US9836639B2 patent drawing

AI summary

An image of a user's eyes and face may be analyzed using computer-vision algorithms. A computing device may use the image to determine the location of the user's eyes and estimate the direction in which the user is looking. The eye tracking technology may be used in a wide range of lighting conditions and with many different and varying light levels. When a user is near a light source, an automatic exposure feature in the camera may result in the user's face and eyes appearing too dark in the image, possibly reducing the likelihood of face and eye detection. Adjusting attributes such as the camera exposure time and the intensity and illumination interval of the light sources based on motion and light levels may improve detection of a user's features.