Watercraft Head-Mounted Display Tracking With Sensor Fusion
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Solution Overview
Problem
Existing head-mounted display tracking systems are not capable of accurately tracking user movement over large volumes or large movements, as they are typically designed for constrained environments like aircraft cockpits, limiting freedom of movement.
Innovation Solution
A tracking system for head-mounted displays that combines optical and non-optical tracking circuitry, including inertial sensors and prediction circuitry, to provide accurate tracking over large areas by selecting appropriate tracking means based on the location of the display and using size-variable optical tracking marks to maintain accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional optical tracking systems are used in constrained environments, then tracking precision is maintained, but the system cannot accurately track movement over large volumes or large movements
Solution Approach 1:
The tracking system is divided into multiple optical tracking means positioned at different locations throughout the watercraft, each responsible for tracking within its local zone. This segmentation allows the system to cover large volumes while maintaining local tracking precision through distributed measurement points.
Solution Approach 2:
Optical tracking marks are introduced as intermediary elements between the head-mounted display and the optical tracking means. These marks serve as mediators that enhance the detectability of the display's position and orientation, enabling accurate tracking across large volumes by providing consistent reference points that the optical system can reliably measure.
2Adaptability or versatility
If the user is allowed to move freely over large volumes, then freedom of movement is improved, but tracking accuracy deteriorates due to the limitations of traditional tracking systems
Solution Approach 1:
The watercraft is divided into multiple tracking zones with optical tracking means distributed throughout. This allows users to move freely across different zones while each local tracking means maintains accurate tracking within its zone, combining overall freedom of movement with local measurement precision.
Solution Approach 2:
The optical tracking marks serve multiple functions: they enable tracking across large volumes, work with both optical and non-optical tracking means, and maintain accuracy regardless of the user's position or orientation. This multi-functionality supports both freedom of movement and tracking accuracy simultaneously.
3Ease of manufacture
If optical tracking marks are used at fixed sizes, then manufacturing is simplified, but tracking accuracy varies with distance from the tracking mark
Solution Approach 1:
The optical tracking marks transition from fixed static sizes to dynamic size-variable configurations. Marks closer to the center of the watercraft are smaller, while those farther away are larger. This dynamic sizing compensates for perspective effects and maintains consistent apparent size across different viewing distances, preserving tracking accuracy throughout the volume.
Solution Approach 2:
The physical parameter of track mark size is changed based on spatial position. By varying the size parameter of tracking marks according to their distance from the center or from expected viewing positions, the system maintains consistent measurement precision across large volumes while keeping the manufacturing process relatively straightforward through systematic size variation.
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
Enables accurate tracking of head movements over large volumes, reducing perceived latency and improving symbol conformity with objects in the user's field of view, even in environments with significant deformation and motion.
Implementation Method 1
The optical tracking means may comprise at least one optical source, such as a laser or light emitting diode, and at least one optical detector
Implementation Method 2
The set of non-optical tracking means may comprise at least one inertial sensor
Data Source
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AI summary
A tracking system for use with a head mounted display on a watercraft is disclosed. The tracking system comprises: optical tracking circuitry to determine first tracking information of the head mounted display using optical tracking means; non-optical circuitry to determine second tracking information of the head mounted display using non-optical tracking means; and correction circuitry to determine an updated tracking information of the head mounted display based on the first tracking information and the second tracking information. The selection of at least the optical tracking means or non-optical tracking means to use to determine the first tracking information and the second tracking information is based on a location of the head mounted display.