Polarized Motion Tracking for Low-Latency 6DoF Head Displays

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Solution Overview

Problem

Existing movement tracking systems for head-worn displays are often expensive, bulky, and suffer from latency issues, making them unsuitable for applications like aviation where timely and accurate information is crucial.

Innovation Solution

A polarization-based system that uses multiple emitters and detectors to track the orientation and position of a head-worn display relative to a platform, providing high accuracy, low latency, and a reduced form factor, with the ability to determine all six degrees of freedom.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If inertial, magnetic, ultrasonic, or camera-based optical tracking systems are used for head-worn displays, then movement tracking capability is achieved, but the system becomes expensive, bulky, and experiences latency issues

Engineering Contradiction:
Improvemovement tracking accuracyVSAvoidsystem bulk and cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical tracking systems (inertial sensors, magnetic sensors, ultrasonic transducers, camera-based optical systems) with a lightweight polarized electromagnetic radiation system. This substitution maintains measurement precision while dramatically reducing device complexity, bulk, and cost by using simple polarized emitters and detectors instead of bulky mechanical components

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental operating parameters of the tracking system by using polarized electromagnetic radiation in the visible or near-infrared spectrum. This parameter change enables the system to achieve high-precision tracking with minimal hardware, as the polarized light interaction provides sufficient measurement data without requiring complex sensor arrays or processing systems

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If complex tracking systems are used to ensure timely information delivery, then movement tracking accuracy is improved, but latency increases

Engineering Contradiction:
Improvetracking accuracyVSAvoidtracking latency
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces processing-intensive mechanical tracking systems with a simple polarized light detection system that requires minimal computation. The direct detection of polarized electromagnetic radiation by photodetectors provides immediate measurement data with no complex filtering or integration required, thereby achieving high tracking accuracy while minimizing latency

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Volume of moving object

If a compact NTE form factor is used, then device portability is improved, but tracking functionality becomes limited

Engineering Contradiction:
Improvedisplay system sizeVSAvoidtracking capability
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent achieves full six-degree-of-freedom tracking capability in a compact NTE form factor by using polarized electromagnetic radiation that can detect both angular and linear movements. The polarized light system serves multiple tracking functions simultaneously (pitch, roll, yaw, and translational movements) without requiring separate sensor systems, thereby maintaining versatility while minimizing device volume

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

The system achieves sub-millisecond latency, reduced cost, and simplified installation, enabling accurate tracking of complex movements while tolerating metallic structures, thereby enhancing the operational efficiency of head-worn display systems in various applications.

Implementation Method 1

transmitting polarized electromagnetic radiation from a plurality of emitters, the emitters affixed to the platform

Methodology Applied
Scientific EffectPolarized electromagnetic radiation: Polarisation

Implementation Method 2

receiving the polarized electromagnetic radiation by a plurality of polarized detectors affixed to the object

Methodology Applied
Scientific EffectPolarized electromagnetic radiation detection: Polarisation

Data Source

PatentEP2910994B1Polarized tracker system and method for tracking movement
Publication Date: 2021.09.08 HONEYWELL INTERNATIONAL INC
  • EP2910994B1 patent drawingFigure 1~3
  • EP2910994B1 patent drawingFigure 2
  • EP2910994B1 patent drawingFigure 4~5

AI summary

A system and method are provided for leveraging emitted polarized electromagnetic radiation as a means to track relative orientation and position of an object with regard to another object. Six basic degrees of freedom including three angular and three translational are determined based on making multiple polarization-based measurements and then determining the corresponding geometry that would yield those measurements.