Mixed Reality Tracking via EMF and Optical Fusion
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Solution Overview
Problem
Conventional mixed reality systems face inaccuracies and limitations in tracking handheld controllers and physical objects due to lack of precise resolution, reliance on external cameras, and signal degradation from stationary transmitters with short ranges, leading to unreliable tracking and tethered user experiences.
Innovation Solution
A mixed reality system incorporating a head-mounted display with a location sensor and a base station emitting an electromagnetic field, combined with an electromagnetic field sensor on objects, forms a magnetic tracking system, which is augmented by an optical tracking system using markers and sensors to enhance accuracy and freedom of movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If stationary transmitters with short transmission range are used for physical object tracking, then device complexity is reduced, but tracking reliability deteriorates due to signal degradation toward the limits of transmission range
Solution Approach 1:
The patent transitions from electromagnetic field-based tracking to optical field-based tracking by using visible light cameras and markers. This dimensional change in the tracking field allows for extended range without signal degradation, while maintaining relatively simple device complexity through the use of standard camera hardware and visual markers.
2Measurement precision
If externally positioned cameras are used for handheld controller tracking, then measurement precision is improved, but ease of operation deteriorates due to tethering use of the HMD device to a small area
Solution Approach 1:
The patent merges the camera system directly into the HMD device, combining the HMD and external camera into a single integrated unit. This integration eliminates the need for separate external cameras and tethering equipment, thereby improving user mobility while maintaining tracking precision through the HMD's onboard camera and marker system.
3Device complexity
If conventional controllers are used for tracking, then device complexity is reduced, but measurement precision deteriorates resulting in choppy, inaccurate display of virtual objects
Solution Approach 1:
The patent uses visual markers with distinct color patterns attached to controllers and tracked objects. These color-coded markers are detected by the HMD camera system, enabling precise identification and tracking of multiple objects. The color changes and patterns provide high-contrast visual signals that improve measurement precision for virtual object display accuracy while maintaining simple controller structures.
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 provides precise and reliable tracking of objects, reducing latency and increasing user interaction by determining object locations in space with high accuracy, even beyond the range of the base station, and seamlessly integrating virtual objects with the real world.
Implementation Method 1
a base station mounted at a fixed position relative to the HMD device a predetermined offset from the location sensor and configured to emit an electromagnetic field (EMF)... an EMF sensor affixed to an object and configured to sense a strength of the EMF
Implementation Method 2
an optical tracking system comprising at least one marker and at least one optical sensor configured to capture optical data
Data Source
AI summary
A mixed reality system may comprise a head-mounted display (HMD) device with a location sensor and a base station, mounted a predetermined offset from the location sensor, that emits an electromagnetic field (EMF). An EMF sensor affixed to an object may sense the EMF, forming a magnetic tracking system. The HMD device may determine a relative location of the EMF sensor therefrom and determine a location of the EMF sensor in space based on the relative location, the predetermined offset, and the location of the location sensor. An optical tracking system comprising a marker an optical sensor configured to capture optical data may be included to augment the magnetic tracking system based on the optical data and a location of the optical sensor or marker. The HMD device may display augmented reality images and overlay a hologram corresponding to the location of the EMF sensor over time.