Retroreflector HMD Tracking via Scanning Beam Reflection
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Solution Overview
Problem
Current head-mounted display (HMD) tracking systems require cumbersome setups with wired peripherals, such as emitters and sensors, which are unsightly, difficult to manage, and limit the placement of devices, hindering adoption and use due to complexity and aesthetic issues.
Innovation Solution
The use of corner reflectors positioned throughout the interactive environment to reflect a scanning beam emitted by the HMD, allowing for precise tracking of the HMD's location and orientation without additional wiring, using a processor to determine the HMD's position based on the reflection times and patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wired peripherals (emitters and sensors) are used for HMD tracking, then tracking precision is improved, but device complexity and ease of operation deteriorate due to cumbersome setup and management
Solution Approach 1:
The patent extracts the tracking functionality from the HMD itself and places passive retroreflective markers in the environment. The HMD becomes a simple observer using its existing camera, while the markers carry the tracking information passively, eliminating the need for active wired peripherals on the HMD.
Solution Approach 2:
The patent introduces environmental markers as intermediary objects that mediate between the HMD and the tracking system. These markers serve as passive intermediaries that reflect light and provide tracking data without requiring power or complex electronics, simplifying the overall system.
2Reliability
If wired peripherals are used for HMD tracking, then tracking reliability is improved, but ease of operation worsens due to difficult management and placement limitations
Solution Approach 1:
The patent removes the active tracking components from the HMD and places passive markers in the environment. This extraction allows the HMD to move freely without cable constraints while the markers remain stationary and reliable tracking references.
Solution Approach 2:
The environmental markers serve themselves by passively reflecting light and providing tracking information without requiring power, configuration, or management. They automatically fulfill their tracking function based on their physical placement in the environment.
3Measurement precision
If multiple wired devices are used for tracking, then measurement precision is improved, but aesthetic appearance deteriorates due to unsightly cables and peripherals
Solution Approach 1:
The patent extracts the visible tracking components from the HMD and places inconspicuous markers in the environment. This eliminates the unsightly cables and peripherals while maintaining tracking accuracy through the HMD's existing camera observing the markers.
Solution Approach 2:
The patent uses the HMD's existing camera to capture images of the environmental markers, effectively copying the visual information from the physical world into the digital tracking data. This approach leverages existing visual hardware rather than adding specialized tracking peripherals.
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 solution provides accurate and responsive tracking of the HMD's location and orientation, eliminating the need for cumbersome wired peripherals and allowing for discreet placement of reflectors, enhancing the user experience with reduced setup complexity.
Implementation Method 1
each of the plurality of retroreflectors is configured to reflect the scanning beam back to the HMD along a return path that is substantially parallel and substantially coincident to an emission path along which the scanning beam was emitted from the emitter
Data Source
AI summary
A system is provided, including: a head-mounted display (HMD), including, a plurality of retroreflectors, and a display device; an emitter/detector unit, including, an emitter configured to emit a scanning beam into an interactive environment, the scanning beam being configured to continuously trace a predefined scan pattern, and a detector configured to detect reflections of the scanning beam back to the HMD by each of the plurality of retroreflectors; a computing device, including, a processor configured to, for each retroreflector, determine a time at which the reflection occurred, wherein the time is used to determine a location or orientation of the HMD in the interactive environment, the computing device configured to generate a view of a virtual space based on the determined location or orientation of the HMD; wherein the display device of the HMD is configured to render the view of the virtual space.