VR Hand Controller Pose Tracking via HMD Diffuse Light Lookup
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Solution Overview
Problem
Conventional virtual reality (VR) systems require external systems with fixed transmitters and high-bandwidth sensors to track the position and orientation of hand controllers, which are costly, space-intensive, and sensitive to optical noise.
Innovation Solution
The VR system uses diffuse electromagnetic radiation from LEDs in a head-mounted display (HMD) detected by photodiodes in the hand controller, comparing the patterns to a lookup table to determine position and orientation with sub-millimeter accuracy, eliminating the need for external transmitters and high-bandwidth sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external fixed transmitters and high-bandwidth sensors are used to track hand controller position and orientation, then tracking accuracy is improved, but system cost and device complexity increase
Solution Approach 1:
The patent uses a simplified optical copying approach where LEDs in the HMD create virtual optical markers that the hand controller's photodiodes detect. Instead of complex external transmitters and sensors, the system copies the essential tracking function using diffuse light patterns from standard LEDs, achieving accurate position and orientation detection through pattern recognition rather than high-bandwidth sensor data
Solution Approach 2:
The patent extracts the tracking function from the external system and relocates it to the HMD itself. By placing LEDs in the HMD and photodiodes in the hand controller, the system eliminates the need for external fixed transmitters and high-bandwidth sensors, achieving tracking using only the diffuse light already present in the virtual reality environment
2Reliability
If external fixed transmitters are used for tracking, then tracking reliability is improved, but space requirements and installation complexity increase
Solution Approach 1:
The patent merges the transmitter function into the HMD that the user already wears. The LEDs in the HMD serve dual purposes: providing visual output for the virtual reality experience and serving as optical markers for tracking the hand controller. This eliminates the need for separate external transmitter infrastructure and reduces space requirements to just the wearable HMD volume
Solution Approach 2:
The HMD serves itself by providing the optical markers needed for tracking. Instead of requiring external systems to illuminate the scene, the HMD's own display elements (LEDs) create the optical patterns that enable the hand controller to determine its position and orientation, making the system self-sufficient and eliminating installation complexity
3Measurement precision
If high-bandwidth sensors are used to detect transmitter signals, then measurement precision is improved, but sensitivity to optical noise increases
Solution Approach 1:
The patent uses periodic pulsing of the LEDs in the HMD to create time-synchronized optical markers. The hand controller's photodiodes detect these periodic light pulses and use timing information to distinguish the structured light patterns from ambient optical noise, achieving accurate tracking without requiring high-bandwidth sensors that would be sensitive to noise
Solution Approach 2:
The patent utilizes different wavelengths (colors) of light from multiple LEDs to create distinctive optical patterns. The photodiodes in the hand controller detect these color-coded light patterns and use wavelength discrimination to filter out ambient optical noise, maintaining measurement precision without requiring high-bandwidth sensors
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 simplifies and reduces costs while maintaining accuracy in tracking the hand controller's position and orientation, reducing sensitivity to external light and eliminating the need for large spaces.
Implementation Method 1
The method can include receiving, by processing circuitry, a pulse of diffuse electromagnetic radiation from a plurality of radiation transmitters placed in the HMD. The method can also include generating, by the processing circuitry, a digital signal from the diffuse electromagnetic radiation.
Data Source
AI summary
Techniques of tracking a hand controller in a VR system involves detecting, by photodiodes in the hand controller, patterns of diffuse radiation generated by diffuse LEDs in the HMD. Such techniques can also include comparing the detected patterns to those simulated offline previously and represented in a lookup table (LUT). By looking up the detected patterns in the LUT, the VR system may determine the position and/or orientation of the hand controller with sub-millimeter accuracy. Some advantages of the improved techniques can be in the simplicity and/or low cost of the components without sacrificing accuracy in deriving the position and orientation of the hand controller.