Capture Ball Reflective Marker Distribution for Motion Capture
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Solution Overview
Problem
Current optical motion capture systems face challenges in recognizing the motion posture and trajectory of capture balls due to the high number of reflective markers required, leading to increased calculation complexity and potential misidentification, especially when the ball's size and motion are unpredictable.
Innovation Solution
A method for uniformly distributing reflective marking points on the surface of a capture ball, using geometric figures like regular hexagons and pentagons, to reduce the number of markers needed for motion-posture recognition, allowing for quicker and more accurate identification of the ball's motion and posture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of reflective markers are distributed on the capture ball to comprehensively recognize motion posture, then the recognition accuracy is improved, but the calculation amount increases tremendously
Solution Approach 1:
The patent extracts only the essential information needed for motion capture by using a minimal set of reflective markers (e.g., 3 markers) instead of distributing numerous markers across the ball surface. This extraction principle reduces the data processing burden while maintaining sufficient information to determine ball position and posture through geometric calculations of marker relationships.
Solution Approach 2:
The patent segments the motion capture problem into independent components: each reflective marker is treated as an independent detection target, and their spatial relationships are calculated separately to determine overall ball posture. This segmentation allows the system to process marker positions independently and combine results, reducing computational complexity compared to treating the entire ball surface as a unified recognition target.
2Ease of operation
If the capture ball has a relatively large diameter, then it is easier to capture and recognize, but it causes unpredictable blocking of the reflective sticker during movement, affecting the capturing process
Solution Approach 1:
The patent applies local quality by strategically positioning reflective markers at specific locations on the ball surface (e.g., vertices of inscribed geometric shapes) rather than uniformly distributing them. This localized placement ensures that at least some markers remain visible and detectable from various angles, reducing the impact of blocking caused by the ball's size and movement while maintaining ease of capture.
Solution Approach 2:
The patent accounts for the dynamic nature of ball movement by placing markers in positions that maximize visibility during rotation and translation. The geometric arrangement of markers ensures that regardless of the ball's orientation during movement, the camera system can detect at least a subset of markers to calculate position and posture, thereby maintaining capture reliability despite the ball's large diameter and unpredictable motion.
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 calculation burden, enhances real-time posture recognition, and minimizes misidentification by concentrating distance values between markers, enabling effective motion capture with fewer markers, thus improving the practicality of the system.
Implementation Method 1
the motion-posture recognition and trajectory tracking for a target object is typically implemented by capturing the motion trajectories of reflective markers
Data Source
AI summary
A capture-ball-based on-ball point distribution method, and a motion-posture recognition method, system, and apparatus are provided. The on-ball point distribution method is used for optical motion capture, and includes dividing a surface of a ball into a plurality of sub-regions, and distributing reflective marking points in the plurality of sub-regions such that a distribution of distance values between any two reflective marking points is concentrated. The reflective marking points are used for the optical motion capture of the ball. According to the on-ball point distribution method and the motion-posture recognition method, system, and apparatus, misrecognition caused by matching errors of the reflective marking points and increased coordinate errors of the spherical center can be effectively avoided. As such, the recognition degree of the capture ball in the system is improved.