VR Sensor Calibration Using Magnetic Loops and Optical Fiducials
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Solution Overview
Problem
Existing calibration procedures for magnetic sensors in VR and AR systems are not adaptable for different types of sensors, leading to inaccurate alignment and high latency, which can cause motion sickness and hinder interactive experiences.
Innovation Solution
A system and method for calibrating alignment of two or more magnetic sensors using a controller, waveform generator, and conductive loops to generate specific calibration waveforms for different types of magnetic sensors, enabling accurate orientation determination with low latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single calibration procedure is used for all magnetic sensors, then the calibration process is simple, but the alignment accuracy deteriorates for different sensor types
Solution Approach 1:
The patent applies parameter changes by modifying the calibration waveform characteristics (frequency, amplitude, duration) based on the specific magnetic sensor type being calibrated. The system automatically adjusts calibration parameters such as waveform frequency to match the resonant frequency of different sensor types, and modifies the magnetic field strength parameters to optimize calibration accuracy for each sensor variant.
Solution Approach 2:
The calibration system implements dynamics by automatically adapting the calibration procedure in real-time based on sensor type detection. The system dynamically selects and configures appropriate calibration waveforms, adjusts field generation parameters, and modifies the calibration sequence based on the specific magnetic sensor type identified during the calibration process.
2Manufacturing precision
If complex calibration procedures are used for different sensor types, then alignment accuracy improves, but calibration time increases
Solution Approach 1:
The system performs preliminary action by pre-configuring multiple calibration waveform templates and procedures for different magnetic sensor types. The calibration system automatically detects the sensor type and retrieves the pre-prepared calibration parameters and sequences, eliminating the need for manual configuration and reducing calibration time while maintaining high accuracy.
Solution Approach 2:
The patent optimizes calibration time by using parameter changes to adapt the calibration waveform characteristics to match each sensor type's optimal calibration parameters. This allows the system to perform type-specific calibration efficiently without using a lengthy universal calibration procedure for all sensor types.
3Ease of operation
If calibration is not optimized for different sensor types, then the system is simple to operate, but latency increases causing motion sickness
Solution Approach 1:
The calibration system implements self-service by automatically detecting the magnetic sensor type and selecting the appropriate calibration procedure without user intervention. The system autonomously configures calibration parameters, executes the correct calibration sequence, and optimizes the calibration process based on the detected sensor characteristics, maintaining simplicity while ensuring reliability.
Solution Approach 2:
The system uses feedback mechanisms to detect the magnetic sensor type during calibration and automatically adjusts the calibration parameters accordingly. The feedback loop ensures that the correct calibration procedure is applied to each sensor type, reducing latency and preventing motion sickness while keeping the operation simple for the user.
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
Achieves precise and efficient alignment of magnetic sensors, reducing latency and improving the accuracy of head-tracking in VR and AR systems, enhancing user experience by minimizing motion sickness and enabling interactive applications.
Implementation Method 1
energizing, with the first calibration waveform, a first conductive loop... and a second conductive loop... to generate corresponding first and second electrical output currents, and to provide the first and second electrical output currents to the first conductive loop and the second conductive loop
Implementation Method 2
determining a first measurement, using a first type of magnetic sensor of the display device, indicative of an orientation of a magnetic field produced by the first and second conductive loops when energized with the first calibration waveform
Data Source
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AI summary
A system (900, 1300) for calibrating alignment of magnetic and optical sensors in a virtual reality (VR) or augmented reality (AR) device (58). The system can include a controller (910), a waveform generator (920), and an electrical driver (930). The waveform generator can produce calibration waveforms under control of the controller. The system can also include conductive loops (302, 304) which are energized with electrical currents corresponding to the calibration waveforms. The controller can cause the waveform generator to generate a first calibration waveform to calibrate a first type of magnetic sensor (604) in the display device, and to generate a second calibration waveform to calibrate a second type of magnetic sensor (102) in the display device. The system may also include one or more optical fiducial markers (316) in a known spatial relationship with respect to the conductive loops. The optical fiducial markers can be used to calibrate the alignment direction of one or more optical sensors.