Polarized Filters for Motion Capture Marker Identification
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Solution Overview
Problem
Current motion capture systems face challenges in accurately identifying markers due to light interference from illuminating rings of other cameras within the field of view, leading to misinterpretation and increased post-processing costs.
Innovation Solution
The implementation of polarized material filters over the illuminating devices and lenses of cameras, with orientations chosen based on the presence of other cameras in the field of view, to selectively allow or block light from illuminating rings and enhance marker identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple cameras are positioned to capture motion data from all angles, then measurement completeness is improved, but light interference from other cameras' illuminating rings causes marker misidentification
Solution Approach 1:
A polarizing filter is introduced as an intermediary element between the camera lens and the external light sources. The filter selectively blocks polarized light from other cameras' illuminating rings while allowing unpolarized or differently polarized light from retro-reflective markers to pass through, thereby eliminating the harmful light interference without compromising marker detection capability
Solution Approach 2:
The solution changes the polarization state parameter of light by placing polarizing filters on camera lenses and corresponding polarizers on illuminating rings. By controlling the orientation of these polarizing elements, the system transforms the light interaction characteristics, enabling differentiation between light from markers and light from other cameras' illuminating rings
2Measurement precision
If polarized material is added to cameras to block interference light, then marker identification accuracy is improved, but device complexity increases
Solution Approach 1:
The solution uses thin polarizing film materials that can be easily applied to camera lenses and illuminating rings. These flexible thin films integrate seamlessly into the existing camera structure without requiring complex mechanical modifications, thereby improving measurement precision while minimizing the increase in device complexity
Solution Approach 2:
The system changes the optical parameter (polarization) of the camera setup by adding relatively simple polarizing filters. This parameter change approach achieves significant improvement in marker identification accuracy while avoiding complex structural redesigns, as the polarizing filters are straightforward optical components that can be integrated with minimal modification to the existing camera system
3Object-affected harmful factors
If polarized material is coupled over illuminating devices and lenses, then light interference is reduced, but manufacturing complexity increases
Solution Approach 1:
The polarizing filters are implemented as thin, flexible films that can be easily applied to lenses and illuminating rings during the manufacturing process. This approach allows for simple integration steps such as adhesive bonding or mechanical mounting, thereby achieving effective light interference reduction while maintaining ease of manufacture and avoiding complex assembly procedures
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 approach significantly reduces the number of misinterpreted markers, minimizing the need for manual cleanup and associated production costs by ensuring that only retro-reflective markers are captured, while maintaining accurate tracking.
Implementation Method 1
A plurality of pieces of polarized material coupled over the illuminating device and the lens of each of the cameras, wherein for each individual camera, either a first orientation or a second orientation for the polarized material is selected
Implementation Method 2
the markers 101, 102 are passive spheres comprised of retro-reflective material, i.e., a material which reflects light back in the direction from which it came
Data Source
AI summary
A system, apparatus and method are described for improving marker identification within a motion capture system. For example, a system according to one embodiment of the invention comprises: a plurality of cameras configurable for a motion capture session, each of the cameras having an illuminating device for generating light and a lens for capturing light reflected off of one or more retro-reflective markers used for the motion capture session; and a plurality of pieces of polarized material coupled over the illuminating device and the lens of each of the cameras, wherein for each individual camera, either a first orientation or a second orientation for the polarized material is selected based on which other cameras are within the individual camera's field of view and the orientation of the polarized material used for the other cameras, the first orientation being perpendicular to the second orientation.