Head-Mounted Display Tracking via Joint Points in Blind Zones
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Solution Overview
Problem
Existing motion capture methods for virtual reality, such as vision and ultrasonic based methods, are limited by Field Of View (FOV) and create tracking blind zones, while inertial sensors can only provide precise posture information without accurate position data.
Innovation Solution
A method and apparatus that determine a target joint point when a tracking target enters a blind zone, using inertial sensors to maintain position information of the joint point and relative positional relationship, allowing for precise tracking target position estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vision or ultrasonic based motion capture methods are used, then position information can be obtained, but tracking blind zones are created due to FOV limitations
Solution Approach 1:
The patent combines vision-based/ultrasonic-based position detection with inertial sensor-based posture detection. When the tracking target is within the field of view, vision or ultrasonic methods provide position information. When the target enters a blind zone, inertial sensors continue to track posture changes. The system merges these two approaches to maintain continuous tracking coverage without blind zones, resolving the contradiction between position accuracy and tracking coverage.
Solution Approach 2:
The patent introduces joint points as intermediary reference objects between the camera and the tracking target. When the tracking target enters a blind zone, the system tracks the position and posture of the joint point (which remains visible) and uses the known relative positional relationship between the joint point and tracking target to calculate the tracking target's position. This intermediary approach allows continuous tracking even when the direct line of sight to the target is blocked.
2Measurement precision
If inertial sensors are used for motion capture, then precise posture information is obtained, but accurate position data cannot be provided due to cumulative drift
Solution Approach 1:
The patent implements a feedback mechanism where vision or ultrasonic sensors periodically provide absolute position information to correct the cumulative drift of inertial sensors. When the tracking target is visible, the system uses vision/ultrasonic position data to recalibrate the inertial sensor-based position estimation, thereby maintaining long-term position accuracy while preserving the high-frequency posture tracking capability of inertial sensors.
3Adaptability or versatility
If joint points are used as reference objects, then tracking can continue in blind zones, but system complexity increases due to additional tracking targets
Solution Approach 1:
The patent applies local quality by selecting specific joint points (such as wrist or elbow joints) as reference objects based on their anatomical characteristics and relationship to the tracking target. Rather than tracking all body joints, the system intelligently selects the most suitable joint point that maintains visibility in blind zones while having a predictable and stable relative positional relationship with the tracking target, thereby minimizing system complexity.
Data Source
AI summary
The disclosure relates to a positioning method, apparatus, electronic device, head-mounted display device, and storage medium. The method is suitable for a head-mounted display device. The method determines a target joint point when a tracking target enters a tracking blind zone; the target joint point referring to a joint point in a wearer's body that supports the tracking target to move within the tracking blind zone; determining position information of the target joint point at current moment; determines relative positional relationship information between the target joint point and the tracking target at the current moment; and determines the position information of the tracking target at the current moment, based on the position information of the target joint point at the current moment and the relative positional relationship information at the current moment.