Rigid Support Structures for 3D Motion Capture
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Solution Overview
Problem
Conventional motion capture systems require a large number of cameras and refined lighting conditions, which can lead to inaccuracies and artifacts, especially when tracking objects in dynamic environments or varied lighting scenarios, and struggle to maintain accurate 3D position calculations of marks when only captured by one camera or not captured at all.
Innovation Solution
The system employs rigid or semi-rigid support structures with motion capture marks that maintain fixed distances, allowing for accurate motion capture using fewer cameras and enabling tracking in various lighting conditions, including complete darkness, by determining effective ray traces and estimating orientations through a computer system capable of processing multiple processes simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of cameras are used to ensure accurate 3D position calculations through triangulation, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical/optical triangulation system (multiple cameras) with a computational approach using rigid body constraints and support structure geometry. The system uses known fixed distances between marks on rigid support structures to calculate 3D positions through mathematical constraints rather than requiring multiple camera views for triangulation.
2Measurement precision
If refined lighting conditions are used to enable cameras to detect marks, then measurement precision is improved, but ease of operation worsens due to lighting constraints
Solution Approach 1:
The patent changes the detection parameter from optical reflection (requiring IR lighting) to radio frequency detection. Marks are equipped with RFID tags or similar RF detection capabilities, allowing cameras to detect marks through radio waves rather than optical reflection, thereby eliminating lighting requirements and enabling operation in complete darkness.
3Reliability
If multiple cameras track points during each frame to maintain reliable tracking, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent replaces the redundant mechanical tracking system (multiple cameras tracking each point) with a computational constraint satisfaction system. The known rigid body geometry and fixed mark distances provide mathematical constraints that enable reliable 3D position calculation from fewer camera views, eliminating the need for multiple cameras to simultaneously track each point.
4Device complexity
If support structures with fixed mark distances are used to enable accurate tracking with fewer cameras, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses rigid support structures with fixed geometric relationships between marks. The rigid body constraints ensure that distances between marks remain constant during motion, providing reliable geometric constraints for 3D position calculation. This approach trades manufacturing precision of individual components for the overall rigidity and geometric stability of the support structure system.
Data Source
AI summary
In one general aspect, a method is described. The method includes generating a positional relationship between one or more support structures having at least one motion capture mark and at least one virtual structure corresponding to geometry of an object to be tracked and positioning the support structures on the object to be tracked. The support structures has sufficient rigidity that, if there are multiple marks, the marks on each support structure maintain substantially fixed distances from each other in response to movement by the object. The method also includes determining an effective quantity of ray traces between one or more camera views and one or more marks on the support structures, and estimating an orientation of the virtual structure by aligning the determined effective quantity of ray traces with a known configuration of marks on the support structures.