EOG Eye Tracking via IMU Normalization for HMDs

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Solution Overview

Problem

Infrared (IR) eye tracking in lightweight head-mounted displays (HMDs) faces challenges due to precise camera positioning requirements and excessive processor burden, leading to inadequate battery life and performance issues, with current solutions failing to address these problems effectively.

Innovation Solution

A headset equipped with at least two electrodes, an inertial measurement unit (IMU), and storage that normalizes electrode input using IMU data to perform electrooculography (EOG) eye tracking, allowing for efficient eye tracking and augmented reality content presentation while reducing computational load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If infrared (IR) eye tracking is used in lightweight head-mounted displays, then eye tracking functionality is achieved, but processor burden and power consumption become excessive

Engineering Contradiction:

Improveeye tracking accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces the mechanical/optical IR camera-based eye tracking system with an electrooculography (EOG) system that uses electrical signals from electrodes to detect eye movements. This substitution dramatically reduces computational requirements while maintaining eye tracking functionality, directly addressing the excessive power consumption issue.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from optical reflection (IR) to electrical potential differences (EOG signals). By measuring voltage changes across the eye rather than analyzing reflected infrared light, the system achieves eye tracking with minimal processor burden and power consumption.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If infrared (IR) eye tracking is used in lightweight head-mounted displays, then eye tracking functionality is achieved, but precise camera positioning requirements become untenable

Engineering Contradiction:

Improveeye tracking accuracyVSAvoidcamera positioning requirements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent eliminates the need for precise mechanical positioning of IR cameras by replacing the optical system with EOG electrodes. The electrical measurement approach does not require the same level of mechanical precision as optical systems, simplifying the device structure and making it more suitable for lightweight HMDs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The EOG electrode system serves multiple functions: it detects eye movements for tracking, measures blink events, and can be integrated into the existing HMD structure without requiring dedicated positioning mechanisms. This multi-functionality reduces overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If infrared (IR) eye tracking is used, then eye tracking data is obtained, but host CPU utilization reaches fifty percent of one processor core per eye

Engineering Contradiction:

Improveeye tracking capabilityVSAvoidprocessor availability for other tasks

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent substitutes the computationally intensive IR camera processing with simple EOG signal acquisition and processing. The electrical signals require minimal computational resources to analyze, freeing up the processor for other tasks and improving overall system productivity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses simple, low-cost EOG electrodes that generate easy-to-process signals, replacing the expensive and computationally demanding IR camera system. This approach prioritizes computational efficiency and resource availability over other tasks.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 solution enhances the accuracy and efficiency of eye tracking, enabling effective gaze and eye position estimation with reduced computational burden, allowing for more efficient use of device resources and improved battery life in HMDs.

Implementation Method 1

perform eye tracking using electrooculography (EOG) that is executed based on the normalized input from the at least two electrodes

Methodology Applied

Scientific EffectElectrooculography (EOG):

Implementation Method 2

receive input from the IMU, and normalize the input from the at least two electrodes based on the input from the IMU

Methodology Applied

Scientific EffectInertial measurement:

Data Source

PatentUS11507185B1Electrooculography-based eye tracking using normalized electrode input

Publication Date: 2022.11.22 LENOVO SWITZERLAND INTERNATIONAL GMBH

AI summary

In one aspect, a headset may include at least one processor, at least two electrodes accessible to the at least one processor, an inertial measurement unit (IMU) accessible to the at least one processor, and storage accessible to the at least one processor. The storage may include instructions executable by the at least one processor to receive input from the at least two electrodes, receive input from the IMU, and normalize the input from the at least two electrodes based on the input from the IMU. The instructions may then be executable to perform eye tracking using electrooculography (EOG) based on the normalized input from the at least two electrodes.