HMD Position Tracking with Optical Flow Sensor ICs
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Solution Overview
Problem
Current head-mounted display (HMD) systems face challenges in accurately tracking the position and movement of HMDs with high precision and low latency, especially in dynamic environments, which can lead to motion sickness and poor 3D perception due to disconnects between visual and vestibular inputs.
Innovation Solution
The implementation of a head-mounted display system that includes a forward-facing camera and multiple optical flow sensor integrated circuits (ICs) with overlapping fields of view, processing image data from these sensors, along with inertial measurement units (IMUs), to track the position, orientation, and movement of the HMD in real-time, enhancing positional tracking accuracy and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensor ICs with overlapping fields of view are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the tracking system into multiple sensor ICs, each with a specific field of view, rather than using a single omnidirectional sensor. This segmentation allows each sensor to focus on a particular direction, improving measurement precision in that direction while the collective arrangement provides comprehensive coverage.
Solution Approach 2:
The patent transitions from a single-point tracking approach to a multi-point spatial distribution of sensors. By arranging sensor ICs at different positions and orientations, the system adds spatial dimensionality to the tracking capability, enabling more accurate position determination through triangulation and overlapping field coverage.
2Speed
If real-time processing of image data from multiple sensors is performed, then speed of tracking is improved, but use of energy increases
Solution Approach 1:
The patent performs preliminary processing of image data from sensor ICs to generate candidate feature points before final position calculation. This preliminary action reduces the computational burden on the main processor by pre-identifying relevant features, enabling faster real-time tracking while reducing overall energy consumption.
Solution Approach 2:
The system uses the sensor ICs to not only track position but also to provide feedback for adjusting the tracking algorithm parameters. This self-service approach allows the system to optimize its own processing efficiency, maintaining high tracking speed while adapting energy consumption to actual operational needs.
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 high-precision, real-time tracking of the HMD's position and movement, improving user experience by minimizing motion sickness and enhancing 3D perception through accurate representation of user movements and virtual environments.
Implementation Method 1
a plurality of optical flow sensor integrated circuits (ICs) that are operative to capture image sensor data in a respective plurality of sensor IC fields of view at a second frame rate
Implementation Method 2
a forward camera that is operative to capture image sensor data in a forward camera field of view at a first frame rate
Data Source
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AI summary
Systems and methods for tracking the position of a head-mounted display (HMD). The HMD may include a support structure that carries a forward facing camera and a plurality of optical flow sensor integrated circuits (ICs). The forward camera captures image sensor data in a forward camera field of view (FOV) at a first frame rate, and each of the plurality of sensor ICs captures image sensor data in a respective plurality of sensor IC FOVs at a second frame rate. The sensor IC FOVs may collectively cover at least a substantial portion of the forward camera FOV. A processor may receive the image sensor data from the camera and the plurality of sensor ICs. The processor may process the received image sensor data and/or other sensor data (e.g., IMU data) to track a position of the head-mounted display based on the processing of the received sensor data.