Gaze Tracking Circuitry with Depth Cross-Check for Fixation Distance
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Solution Overview
Problem
Challenges exist in accurately determining the fixation distance of a user's gaze using gaze tracking circuitry due to small errors in measured gaze position, leading to significant estimation inaccuracies.
Innovation Solution
Combining gaze tracking circuitry with depth sensors to cross-check vergence-based fixation distance estimates, utilizing hysteresis and threshold changes in vergence to refine fixation distance calculations, and analyzing depth maps around the gaze position to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gaze tracking circuitry is used to determine fixation distance, then the system can provide basic gaze direction tracking, but small errors in measured gaze position result in significant errors in estimated fixation distance
Solution Approach 1:
The patent combines gaze tracking circuitry with depth sensing circuitry into an integrated system. The depth sensor provides independent depth measurements that are fused with gaze direction data, creating a hybrid estimation approach that compensates for the sensitivity of pure vergence-based methods to measurement errors
Solution Approach 2:
The system uses depth map data as feedback to validate and refine fixation distance estimates. By comparing vergence-based predictions with actual depth sensor measurements, the system can detect and correct errors, improving overall estimation reliability
2Measurement precision
If depth sensor is activated continuously to measure depth maps, then fixation distance accuracy is improved, but energy consumption increases
Solution Approach 1:
The depth sensor is activated periodically or on-demand rather than continuously. The system triggers depth map acquisition based on gaze stability criteria or when verification of fixation distance is needed, reducing power consumption while maintaining accuracy when required
Solution Approach 2:
The depth sensor measures depth maps at selective moments rather than continuously, providing sufficient verification capability without the full energy cost of continuous operation. The system uses histogram analysis of partial depth data to achieve accurate fixation distance determination
3Measurement precision
If histogram analysis of depth values is performed to determine fixation distance, then estimation accuracy is improved, but computational complexity increases
Solution Approach 1:
The histogram analysis is performed locally on depth values within a specific angular range around the measured gaze position, rather than analyzing the entire depth map. This localized approach reduces computational complexity while maintaining accuracy by focusing only on relevant depth data
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
Improves the accuracy of fixation distance estimation by reducing errors and ambiguities, ensuring precise adjustment of lenses and displays based on the user's gaze direction.
Implementation Method 1
The gaze tracking circuitry may include light-emitting diodes and a camera
Implementation Method 2
A depth sensor may measure a depth map of an environment that is viewed through the lens
Data Source
AI summary
Eyewear such as a head-mounted device may include adjustable prescription lenses and/or displays. The eyewear may include gaze tracking circuitry that tracks a gaze direction of a user. A depth sensor may measure a depth map of an environment that is viewed through the lens. Using the principals of vergence, a fixation distance may be determined based on the binocular gaze directions of the user. The estimated fixation distance may be cross-checked with the depth map to obtain a more accurate fixation distance estimate. For example, when the gaze tracking circuitry detects a change in gaze direction that exceeds a threshold, a depth map may be analyzed to determine where the new gaze position intersects with the depth map. If desired, depth data may only be gathered and/or analyzed for a subregion of the environment surrounding the measured gaze position.