EM Head Tracking for AR With Low-Latency Pose Localization
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Solution Overview
Problem
Current augmented reality systems face challenges in accurately and efficiently localizing the position and orientation of objects, particularly head pose and real-world objects, due to high latency and low precision in tracking, which can lead to motion sickness and unstable virtual object placement.
Innovation Solution
The implementation of an electromagnetic tracking system that uses a magnetic field emitter and sensors to determine the position and orientation of objects with high accuracy and low latency, combined with inertial measurement units and cloud-based processing for enhanced localization and interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electromagnetic tracking system is implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system divides tracking functionality into separate modules: electromagnetic field emitter, field sensors, inertial measurement units, and cloud-based processing. Each component performs a specific function, allowing high precision tracking while managing complexity through modular architecture.
Solution Approach 2:
The patent introduces cloud-based processing as an intermediary between the AR device and the tracking algorithm execution. This offloads complex computational tasks from the wearable device, reducing its complexity while maintaining high measurement precision through sophisticated processing.
2Loss of time
If electromagnetic tracking system is implemented, then latency is reduced, but use of energy increases
Solution Approach 1:
The system performs preliminary actions by pre-processing data locally on the AR device and pre-positioning computational tasks in the cloud. This reduces the latency for actual tracking operations while managing energy consumption through efficient task distribution.
Solution Approach 2:
The patent implements periodic updates from inertial measurement units combined with electromagnetic field sampling. This periodic action approach maintains low latency for tracking updates while reducing energy consumption compared to continuous high-frequency sampling.
3Reliability
If multiple sensors and processing units are added, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple sensing modalities (electromagnetic field sensing, inertial measurement) into a unified tracking system. This merging improves reliability by cross-validating measurements from different sensors while managing complexity through integrated processing architecture.
Solution Approach 2:
The system implements feedback loops where cloud-based processing continuously refines tracking estimates based on sensor data from multiple sources. This feedback mechanism improves reliability by correcting drift and errors while managing complexity through iterative processing rather than complex hardware design.
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 provides high-precision, low-latency object tracking, enabling a more immersive and stable augmented reality experience by accurately rendering virtual content relative to real-world objects and improving user interaction.
Implementation Method 1
an electromagnetic, EM, field emitter configured to generate a magnetic field
Implementation Method 2
an EM sensor configured to sense the magnetic field
Data Source
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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. EM information from the sensor can be analyzed to determine location and/or orientation of the sensor and thereby the wearer's pose. The EM emitter and sensor may utilize time division multiplexing (TDM) or dynamic frequency tuning to operate at multiple frequencies. Voltage gain control may be implemented in the transmitter, rather than the sensor, allowing smaller and lighter weight sensor designs. The EM sensor can implement noise cancellation to reduce the level of EM interference generated by nearby audio speakers.