Gaze Tracking Adaptation for Involuntary Head Movements
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Solution Overview
Problem
Existing gaze-based interaction systems struggle with users having involuntary head movements, leading to inaccuracies and difficulties in maintaining stable gaze traces, particularly for individuals with conditions like Athetoid cerebral palsy, post-stroke patients, and severe intellectual disabilities, due to the need for frequent recalibration and the challenges posed by involuntary body movements.
Innovation Solution
An eye-tracking adaptation algorithm that predicts head movements and smooths gaze fixation by detecting initial gaze points, head positions, and rotation angles, generating an adjusted gaze point to stabilize the user's gaze on the screen, using a system with a Head Pose Monitor and Gaze Points Speed Controller to adapt to involuntary head movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If real-time video analysis eye tracking is used to detect pupil centre and corneal reflection, then gaze-based interaction becomes accessible to people with physical limitations, but head stability is required which is not available for users with involuntary head movements
Solution Approach 1:
The patent introduces an intermediary computational model that maps eye tracker coordinates to communication board coordinates dynamically. This mediator layer processes the relationship between gaze points and target areas, allowing the system to compensate for head movements through continuous coordinate transformation rather than requiring physical head stability.
Solution Approach 2:
The system dynamically adjusts the mapping between eye tracker coordinates and communication board coordinates in real-time. Instead of using fixed calibration points, the system continuously updates the coordinate transformation based on current head position and gaze direction, making the interaction adaptive to involuntary movements.
2Measurement precision
If frequent device recalibration is performed to ensure accuracy during involuntary movements, then selection accuracy is maintained, but data inaccuracy occurs during recalibration periods and communication is disrupted
Solution Approach 1:
The system performs preliminary calibration once at the beginning of each interaction session, establishing an initial coordinate mapping. This preliminary action eliminates the need for frequent recalibrations during communication, as the dynamic adjustment mechanism continuously adapts the mapping without requiring full recalibration cycles that would interrupt communication.
Solution Approach 2:
The coordinate mapping system operates continuously throughout the interaction session, constantly updating the transformation between eye tracker and communication board coordinates. This continuous operation maintains selection accuracy without interrupting the communication flow for recalibration, ensuring uninterrupted useful action.
3Measurement precision
If binary position markers are used to compute homograph and maintain coordinate mapping during head movement, then some accuracy is maintained, but sudden involuntary head movements still cause display inaccuracy
Solution Approach 1:
The patent replaces static binary position markers with a dynamic coordinate mapping system that continuously adapts to head movements. The mapping parameters are updated in real-time based on current head position and gaze direction, allowing the system to respond to sudden involuntary movements rather than relying on pre-defined marker positions.
Solution Approach 2:
The system incorporates feedback mechanisms that continuously monitor gaze position and head orientation, using this information to adjust the coordinate mapping in real-time. This feedback loop enables the system to compensate for sudden head movements by detecting the deviation and correcting the mapping accordingly.
Data Source
AI summary
Disclosed is a system and method for adjusting an eye-gaze of a disabled subject having involuntary head movements. The system includes one or more processors and a database coupled to one or more processors, wherein the database includes an adaptation module. The adaptation module is programmable to execute instructions for tracking and monitoring an eye-gaze and head movements of the subject during a gaze-based interaction, computing the tracked eye-gaze and the head movements of the subject based on pre-determined parameters, and generating an adjusted eye-gaze until the interaction completes.