Ambient EM Distortion Correction Using SVD for AR Pose Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electromagnetic tracking systems for augmented and virtual reality devices suffer from ambient electromagnetic field distortions due to nearby electrical conductors or ferromagnetic materials, leading to errors in pose determination and requiring additional data from imaging cameras or other sensors for correction.
Innovation Solution
A novel electromagnetic distortion correction scheme based on singular value decomposition of the electromagnetic field matrix is applied to estimate and correct for distortions in real time, without the need for additional data from imaging cameras or other sensors, using a computationally efficient analytic technique.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electromagnetic tracking systems operate in environments with nearby electrical conductors or ferromagnetic materials, then the system can function in realistic settings, but ambient electromagnetic field distortions cause errors in pose determination
Solution Approach 1:
The patent applies singular value decomposition (SVD) to the electromagnetic field matrix to separate the useful signal from distortion components. By decomposing the field matrix into singular values and vectors, the system identifies and removes distortion caused by ambient electromagnetic sources, converting the harmful distortion into correctable data that improves pose determination accuracy in realistic environments
Solution Approach 2:
The system dynamically adjusts processing parameters by computing the singular value decomposition of the electromagnetic field matrix in real-time. This mathematical transformation changes the representation of the field data from raw sensor readings to a decomposed form that separates signal from noise, enabling adaptive correction of distortion based on actual environmental conditions
2Measurement precision
If additional sensors or imaging cameras are used to correct electromagnetic distortion, then pose accuracy can be improved, but device complexity and weight increase
Solution Approach 1:
The electromagnetic tracking system corrects its own distortion errors using only its existing electromagnetic sensors and the SVD mathematical process. The system processes its own field matrix data to identify and remove distortion components, eliminating the need for external correction sensors or imaging cameras while maintaining high pose determination accuracy
Solution Approach 2:
The patent replaces physical correction mechanisms (additional sensors, cameras, or mechanical calibration systems) with a mathematical computation approach. By using singular value decomposition of the electromagnetic field matrix, the system achieves distortion correction through data processing rather than additional hardware, reducing device complexity and weight
3Measurement precision
If iterative numerical methods are used to determine pose from electromagnetic field matrix, then accuracy can be improved, but computational efficiency decreases and latency increases
Solution Approach 1:
The patent replaces iterative numerical optimization methods with a direct closed-form solution using singular value decomposition. This mathematical approach computes the pose directly from the electromagnetic field matrix without requiring repeated calculations or convergence checks, achieving both high accuracy and computational efficiency suitable for real-time augmented reality applications
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 method provides accurate and low-latency pose determination with high precision, enabling effective virtual content display and interaction in augmented reality environments.
Implementation Method 1
an electromagnetic (EM) emitter generates an EM field, and the head-mounted AR device can include an EM sensor that senses the EM field
Implementation Method 2
a novel EM distortion correction scheme based on singular value decomposition of an EM field matrix can be applied to estimate whether EM distortion exists and to correct for the distortion
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Head-mounted augmented reality (AR) devices can track pose of a wearer's head to provide a three-dimensional virtual representation of objects in the wearer's environment. An electromagnetic (EM) tracking system can track head or body pose. A handheld user input device can include an EM emitter that generates an EM field, and the head-mounted AR device can include an EM sensor that senses the EM field (e.g., for determining head pose). The generated EM field may be distorted due to nearby electrical conductors or ferromagnetic materials, which may lead to error in the determined pose. Systems and methods are disclosed that measure the degree of EM distortion, as well as correct for the EM distortion. The EM distortion correction may be performed in real time by the EM tracking system without the need for additional data from imaging cameras or other sensors.