LED-Based Gaze Tracking for Head-Mounted Displays
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Solution Overview
Problem
Conventional gaze tracking systems for head-mounted displays are bulky, expensive, and have high power consumption due to camera-based imaging techniques, leading to latency and complexity, making them unsuitable for low-power mobile solutions.
Innovation Solution
A gaze tracking system using light emitting diodes (LEDs) for both illumination and light capture, combined with photosensor elements like photodiodes, which are lighter, smaller, and consume less power, allowing for a low-power, low-latency, and computationally efficient gaze estimation pipeline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If camera-based imaging techniques are used for gaze tracking, then gaze direction can be detected, but power consumption increases and device bulk increases
Solution Approach 1:
The patent extracts the gaze tracking function from complex camera-based imaging systems and implements it using simplified photodiode arrays that directly detect light intensity patterns from the eye, eliminating the need for full image processing while maintaining gaze detection capability
Solution Approach 2:
The patent replaces the mechanical/optical imaging system (cameras) with an electrical sensing system (photodiodes) that converts light intensity directly into electrical signals for gaze estimation, reducing power consumption and processing requirements
2Measurement precision
If camera-based imaging techniques are used for gaze tracking, then gaze direction can be detected, but device complexity and cost increase
Solution Approach 1:
The patent extracts only the essential light detection function needed for gaze tracking from complete camera systems, using photodiode arrays that measure light intensity patterns without requiring full imaging capabilities, thus simplifying the device
Solution Approach 2:
The patent uses inexpensive photodiode components instead of expensive camera modules, accepting that simpler components require different processing approaches but achieving cost-effective gaze tracking
3Measurement precision
If high-resolution images are processed for gaze tracking, then measurement precision improves, but latency increases
Solution Approach 1:
The patent extracts only the critical light intensity measurement data from full image processing, using photodiode arrays that provide direct intensity readings without requiring capture, transmission, and processing of complete high-resolution images
Solution Approach 2:
The patent uses a simplified sensing approach with photodiodes that captures only the necessary light intensity information for gaze estimation, performing partial processing rather than complete image analysis, thus reducing latency while maintaining sufficient precision
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
The system achieves accurate gaze tracking with reduced bulk, power consumption, and latency, providing higher sensing rates and accuracy, with mean angular error as low as 1.1° and median angular error of 0.7°, suitable for battery-operated applications.
Implementation Method 1
a plurality of light emitting diodes coupled to the opaque frame for emitting infrared light onto an eye gazing through the transparent field of view
Implementation Method 2
sensing intensity of infrared light reflected off of the eye
Implementation Method 3
one or more photosensor elements positioned behind the lens in the optical path... for sensing intensity of infrared light
Data Source
AI summary
A gaze tracking system for use in head mounted displays includes an eyepiece having an opaque frame circumferentially enclosing a transparent field of view, light emitting diodes coupled to the opaque frame for emitting infrared light onto various regions of an eye gazing through the transparent field of view, and diodes for sensing intensity of infrared light reflected off of various regions of the eye.