Dual LED Glint Detection for Wearable Eye Tracking
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Solution Overview
Problem
Current wearable computing systems face challenges in accurately determining gaze direction for interactive user interfaces, particularly in dynamic environments, due to limitations in eye-tracking technologies that rely on single intensity-level light sources and imaging techniques.
Innovation Solution
The method involves using dual or multiple light sources with adjustable intensity levels to illuminate a viewing location, acquiring images during different intensity periods, and combining data from these images to determine gaze direction, incorporating infrared LEDs and cameras to capture glint reflections and pupil location for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single light source is used for illumination, then the device complexity is reduced, but the measurement precision of gaze direction deteriorates
Solution Approach 1:
The illumination function is segmented into multiple light sources with different intensity levels. The system divides the lighting task among at least a first light source and a second light source, where each contributes to creating glint reflections at different intensities, thereby improving gaze measurement precision without requiring a single complex light source
Solution Approach 2:
The system dynamically switches between different light source intensity levels across multiple time periods. During a first time period, the first light source illuminates at a higher intensity; during a second time period, the second light source illuminates at a different intensity. This dynamic intensity variation enables more accurate glint detection and gaze direction determination
2Measurement precision
If multiple intensity levels are used for illumination, then the measurement precision of glint location is improved, but the use of energy increases
Solution Approach 1:
The system employs periodic illumination cycles alternating between different light source intensity levels. Instead of continuously operating multiple light sources at maximum intensity, the system switches between the first light source at higher intensity and the second light source at different intensity during alternating time periods, reducing overall energy consumption while maintaining measurement precision
Solution Approach 2:
The system changes the illumination intensity parameter by switching between different light sources with different intensity characteristics. This parameter variation allows the system to capture glint reflections at multiple intensity levels for improved measurement precision, while managing energy consumption by not maintaining all high-intensity sources simultaneously
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 more accurate and reliable gaze direction determination, enabling better interaction with wearable computing systems through eye movements, improving rotational accuracy and user interface control.
Implementation Method 1
The wearable computing system includes at least a first light source and a second light source
Implementation Method 2
acquiring a first image from light reflected from the viewing location during the first period of time
Data Source
AI summary
A wearable computing system may include an eye-tracking system configured to track the position of an eye of a wearer of the wearable computing system. In particular, an infrared light source illuminating the eye of a wearer at a relatively high intensity may generate specular reflections off the wearer's cornea, also called ‘glints’. The glints can be imaged with an infrared camera. When the infrared light sources are illuminated at a relatively lower intensity, determination of the pupil location is possible. Glints, in combination with the pupil location, may be used to accurately determine the gaze direction and eye rotation. The determined gaze direction could be used in various eye-tracking applications. By controlling the light sources to change intensity levels and by combining multiple images of the eye to incorporate multiple glint locations with the pupil location, eye tracking can be performed with better accuracy and with fewer light sources.