Dual Mode Eye Tracking System Power and IR Exposure Reduction

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Solution Overview

Problem

Conventional eye tracking devices face limitations in accuracy due to their remote configuration, high power consumption, and exposure to infrared light, which reduces usage time and raises safety concerns, especially in outdoor environments.

Innovation Solution

A dual mode eye tracking system that switches between infrared (IR) and visual light (VL) tracking modes, primarily using natural light and secondary IR light, to reduce power consumption and minimize eye exposure to IR radiation, featuring an IR illuminator, image sensing device, and controller that control the light source and image processing to determine and adjust tracking modes based on accuracy thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If IR tracking mode is used continuously to maintain high tracking accuracy, then measurement precision is improved, but use of energy increases and duration of action decreases

Engineering Contradiction:

Improvetracking accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system performs IR tracking periodically at specific time points (e.g., when gaze position changes exceed a threshold) rather than continuously. The controller switches between IR tracking mode for periodic calibration and VL tracking mode for continuous operation, reducing overall power consumption while maintaining tracking accuracy when needed.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system dynamically switches between two tracking modes (IR and VL) based on real-time conditions. The controller monitors tracking accuracy and environmental lighting conditions, then adaptively selects the appropriate mode: IR mode when high precision is required or lighting is poor, and VL mode when conditions permit to save energy.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If IR illuminator is always on to ensure tracking accuracy, then measurement precision is improved, but object-affected harmful factors increase due to continuous IR exposure

Engineering Contradiction:

Improvetracking accuracyVSAvoideye exposure to IR light

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The IR illuminator operates periodically rather than continuously, activating only when IR tracking is required for calibration or when environmental conditions demand it. This periodic operation significantly reduces cumulative IR exposure to the user's eyes while maintaining tracking accuracy when the illuminator is active.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The controller monitors tracking accuracy and environmental lighting conditions in real-time, then provides feedback control for the IR illuminator operation. When tracking accuracy is sufficient with VL mode or environmental lighting is adequate, the controller suppresses IR illuminator operation, thereby reducing harmful IR exposure while maintaining performance.

Inventive Principle:

Principle #23Feedback

3Duration of action of moving object

If VL tracking mode is used to reduce power consumption, then duration of action is improved, but measurement precision deteriorates in low light conditions

Engineering Contradiction:

Improveusage timeVSAvoidtracking accuracy

Core Design Contradiction:

Duration of action of moving objectVSMeasurement precision

Solution Approach 1:

The system dynamically adapts its tracking mode based on environmental lighting conditions. During periods of adequate lighting, VL tracking mode is used to conserve energy. When lighting conditions deteriorate below a threshold, the system automatically switches to IR tracking mode to maintain accuracy, thus optimizing the balance between usage time and tracking precision throughout different environmental conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the tracking system by switching between different light sources (VL vs IR) based on environmental conditions. This parameter change allows the system to maintain tracking accuracy across varying lighting conditions while minimizing power consumption during favorable conditions.

Inventive Principle:

Principle #35Parameter changes

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 approach extends usage time by reducing power consumption and minimizing eye exposure to IR light, while maintaining accurate gaze position tracking, particularly in well-lit environments, by predominantly using natural light and selectively employing IR light only when necessary.

Implementation Method 1

An infrared (IR) ray is emitted to perform the IR tracking mode to obtain a first gaze position

Methodology Applied

Scientific EffectInfrared radiation detection: Absorption (EM radiation)

Implementation Method 2

perform visual light (VL) tracking to obtain a second gaze position

Methodology Applied

Scientific EffectVisual light detection: Photoelectric Effect

Data Source

PatentUS10606352B2Dual mode eye tracking method and system

Publication Date: 2020.03.31 NAT TAIWAN UNIV

AI summary

In a dual mode eye tracking method and system, an infrared (IR) ray is emitted to perform an IR tracking mode and visible light (VL) calibration. When a first error between a VL associated gaze position and an IR associated gaze position is less than a first threshold, the IR ray is turned off to perform a VL tracking mode. In a VL checking period, when a second error between a VL associated gaze position and an IR associated gaze position is less than a second threshold, the IR ray is turned off to continue the VL tracking mode.