VR Headset Calibration Using Locator Tracking
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Solution Overview
Problem
Virtual reality (VR) devices face inaccuracies in tracking headset position and motion due to manufacturing tolerances, leading to discrepancies between actual and expected outputs from cameras and inertial measurement units (IMUs), resulting in dissonance between user motion and media presentation.
Innovation Solution
A headset calibration system that includes cameras, a support arm, and a calibration controller to capture images of the VR headset while it is moved along predetermined paths, determining differences between expected and actual positions of locators and IMU outputs, generating calibration parameters to compensate for manufacturing variations, and applying these parameters to ensure accurate tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If VR headsets are manufactured with standard tolerances, then manufacturing cost and ease of production are improved, but tracking accuracy and measurement precision deteriorate
Solution Approach 1:
The patent applies preliminary action by performing calibration measurements before the VR headset is deployed for use. The system captures images of locators at multiple known positions and orientations, determines actual positions and orientations, calculates calibration parameters, and stores them in memory before normal operation begins. This pre-calibration process eliminates tracking inaccuracies that would otherwise occur during actual use, resolving the contradiction between standard manufacturing tolerances and tracking accuracy requirements.
2Measurement precision
If calibration parameters are stored in memory for compensation, then tracking accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements self-service by having the VR headset perform its own calibration and store the calibration parameters in its internal memory. The headset independently captures images, processes locator positions, calculates calibration parameters, and stores them without requiring external calibration equipment or continuous external intervention. This self-calibrating approach improves tracking accuracy while minimizing additional system complexity, as the headset uses its existing camera and processor resources for the calibration function.
Data Source
AI summary
A virtual reality (VR) headset calibration system calibrates a VR headset, which includes a plurality of locators and an inertial measurement unit (IMU) generating output signals indicative of motion of the VR headset. The system comprises a calibration controller configured to receive a headset model of the VR headset that identifies expected positions of each of the locators. The controller controls cameras to capture images of the VR headset while the headset is moved along a predetermined path. The images detect actual positions of the locators during the movement along the predetermined path. Calibration parameters for the locators are generated based on differences between the actual positions and the expected positions. Calibration parameters for the IMU are generated based on the calibration parameters for the locators and differences between expected and actual signals output by the IMU. The calibration parameters are stored to the VR headset.