Adjustable Gaze-Tracking Illuminators for HMDs
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Solution Overview
Problem
Conventional gaze-tracking techniques in head-mounted display apparatuses face inaccuracies due to obstructions by eyelids and lashes, require specific device positioning, and struggle with changes in pupil shape, leading to geometric aberrations and reflection artifacts.
Innovation Solution
A gaze-tracking system with adjustable illuminators and photo sensors, controlled by a processor, that continuously illuminate the eye and adjust their position based on detected gaze direction, reducing obstructions and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the illumination source and camera are positioned near the periphery of the user's eyes to enable gaze tracking, then gaze tracking functionality is achieved, but the positioning is obstructed by eyelids and eye lashes reducing accuracy
Solution Approach 1:
The patent implements movable illuminators and photo sensors that can dynamically adjust their positions based on detected gaze direction. The actuators enable real-time repositioning of the optical components, transforming them from static peripheral positions to dynamically adjustable positions that maintain optimal alignment with the user's line of sight, thereby resolving the contradiction between achieving gaze tracking functionality and maintaining accuracy despite anatomical obstructions
Solution Approach 2:
The system employs a feedback mechanism where the processor continuously detects gaze direction and uses this information to control actuators that reposition the illuminators and photo sensors. This closed-loop feedback system ensures that the optical components maintain accurate alignment with the user's eyes and line of sight, compensating for anatomical obstructions and maintaining high measurement precision while enabling robust gaze tracking functionality
2Measurement precision
If a hot mirror is arranged within the device to align the camera along the central gaze direction, then gaze alignment is improved, but the device size increases
Solution Approach 1:
Instead of using a static hot mirror that requires additional space, the patent employs movable illuminators and photo sensors controlled by actuators. These components can dynamically adjust their positions to achieve proper alignment along the central gaze direction, eliminating the need for a bulky hot mirror while maintaining alignment accuracy
Solution Approach 2:
The system changes the positional parameters of the illuminators and photo sensors in real-time based on detected gaze direction. By adjusting the spatial coordinates of these components through actuator control, the system achieves accurate gaze alignment without requiring the fixed optical path correction that a hot mirror would provide, thereby reducing device volume
3Measurement precision
If the illumination source and camera are positioned coaxially with the gaze direction for bright-pupil tracking, then pupil detection is improved, but the device becomes large to accommodate the positioning requirements
Solution Approach 1:
The patent implements movable illuminators and photo sensors that can dynamically reposition themselves to achieve coaxial alignment with the user's gaze direction when needed for bright-pupil tracking. The actuators enable these components to adjust their positions in real-time, allowing the system to achieve high pupil detection accuracy without requiring permanent coaxial positioning that would increase device volume
Solution Approach 2:
The movable optical components can operate in multiple configurations - they can achieve coaxial positioning for bright-pupil tracking when high accuracy is needed, and can be repositioned for other operational modes. This multi-functionality allows the system to achieve high pupil detection accuracy without being permanently constrained to a large coaxial configuration, as the components can adapt their positions based on operational requirements
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 provides accurate and efficient gaze tracking, compensates for pupil shape changes, and reduces device size, enhancing the accuracy of gaze direction detection.
Implementation Method 1
an illumination source is employed for emitting light towards the user's eyes, and a camera is employed for capturing an image depicting the pupils of the user's eyes and reflection(s) of the emitted light from the user's eyes
Implementation Method 2
at least one photo sensor for sensing reflections of the light from the user's eye
Data Source
AI summary
A gaze-tracking system for a head-mounted display apparatus includes a first set of illuminators for emitting light to illuminate a user's eye; at least one photo sensor for sensing reflections of the light from the user's eye; at least one actuator for moving at least one of: (i) the first set of illuminators, (ii) the at least one photo sensor; and a processor coupled with the first set of illuminators, the at least one photo sensor and the at least one actuator. The processor is configured to collect and process sensor data from the at least one photo sensor to detect a gaze direction of the user, and to control the at least one actuator to adjust, based upon the detected gaze direction, a position of the at least one of: (i) the first set of illuminators, (ii) the at least one photo sensor.