Contact Lens Shift Detection for Accurate HMD Gaze Tracking
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Solution Overview
Problem
Current head-mounted display (HMD) devices with gaze tracking systems suffer from inaccuracies due to excessive shifting of contact lenses relative to the eye, leading to performance degradation.
Innovation Solution
A contact lens shift detection system is implemented in HMD devices to detect excessive lens shift by analyzing key frames during user enrollment and operation, calculating shift vectors, and comparing their standard deviation to a threshold, triggering notifications or compensation mechanisms as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact lens is worn during HMD operation, then user comfort and visual correction are improved, but excessive lens shift causes gaze tracking inaccuracy and performance degradation
Solution Approach 1:
The system performs preliminary detection during the user enrollment process by capturing multiple key frames and calculating shift vectors to establish a baseline contact lens shift profile before actual gaze tracking begins. This allows the system to pre-compensate for lens shift characteristics specific to each user's contact lenses.
Solution Approach 2:
The system continuously monitors contact lens shift by comparing detected cornea position with expected position across multiple key frames, calculates the standard deviation of shift vectors, and provides feedback by generating notifications when excessive shift is detected or by activating compensation mechanisms to correct the gaze tracking data.
2Reliability
If contact lens shift detection and compensation mechanisms are added to HMD, then gaze tracking accuracy is maintained, but device complexity increases
Solution Approach 1:
The system uses the existing eye tracking camera and processing pipeline to perform contact lens shift detection by analyzing the same key frames already captured for gaze tracking calibration. The detection leverages existing cornea detection algorithms without requiring separate detection hardware or independent processing systems.
Solution Approach 2:
The eye tracking camera serves multiple functions: it captures images for both traditional gaze tracking calibration and contact lens shift detection. The same image processing pipeline extracts both gaze information and cornea position data, allowing one system to perform multiple functions without proportionally increasing complexity.
Data Source
AI summary
Systems and methods are disclosed to enable detection of excessive contact lens shift in a head-mounted display (HMD) device that implement gaze tracking for the user. In embodiments, during a user enrollment process to calibrate the gaze tracking system, the HMD device analyzes key frames of the eye to estimate a first center location of the eye based on detected eye features such as the pupil, the iris, or the limbus, and a second center location of the eye based on the shape of the detected cornea. Shift vectors are generated based on the two center locations for individual key frames. If the standard deviation of the vectors' magnitudes exceeds a specified threshold, excessive lens shift is detected. In response to detection of excessive contact lens shift, the HMD device may generate a notification to the user or activate compensation mechanisms.