Single Camera Planar Tracking for Tennis Line-Calling
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Solution Overview
Problem
Current multi-camera and moving-camera solutions for 3D object-tracking in scenarios like tennis line-calling are costly, require extensive setup and maintenance, and are not practical for smaller venues or individuals, as they rely on external processing and human intervention, limiting their utility to high-end professional settings.
Innovation Solution
A portable, standalone device with a single fixed-location camera, integrated processing mechanism, and auto-calibration capabilities, which simplifies setup and eliminates the need for external devices, allowing for real-time line-calling decisions by detecting the ball bounce as the key object state condition, transforming the 3D tracking problem into a 2D planar problem.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple cameras are used for 3D object-tracking, then measurement precision and reliability are improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent transforms the 3D tracking problem into a 2D planar problem by detecting when the ball reaches the plane of the court surface (bounce detection). By using a single camera to capture 2D images and identifying the moment the ball contacts the court plane, the system avoids the need for multiple cameras to perform full 3D trajectory tracking, thereby reducing device complexity while maintaining line-calling accuracy
Solution Approach 2:
The patent extracts only the essential information needed for line-calling decisions - specifically, the 2D position of the ball at the moment of bounce on the court plane. Rather than tracking the complete 3D trajectory, the system focuses on detecting the bounce event and the ball's position relative to court lines at that specific moment, simplifying the overall system requirements
2Measurement precision
If multiple cameras and external processing devices are deployed, then line-calling accuracy is improved, but ease of operation and setup time deteriorate
Solution Approach 1:
The patent combines the camera, processing unit, and line-calling decision-making capabilities into a single integrated portable device. This eliminates the need for multiple separate cameras and external processing devices, allowing the entire system to be set up by attaching one device to a net post, thereby dramatically improving ease of operation while maintaining accurate line-calling functionality
Solution Approach 2:
The integrated device performs automatic calibration and real-time processing without requiring external equipment or human intervention during operation. The system self-calibrates by detecting court lines and automatically makes line-calling decisions based on ball bounce detection, eliminating the need for operators to coordinate multiple cameras or external systems
3Reliability
If high-end professional systems are used, then reliability and accuracy are improved, but loss of substance (cost) increases
Solution Approach 1:
The patent employs a single camera instead of expensive multi-camera systems, using a more affordable, simpler imaging device that can be easily replaced or moved. This approach achieves reliable line-calling at a fraction of the cost of professional systems like Hawk-Eye, making the technology accessible to smaller venues while maintaining sufficient accuracy through the 2D planar solution
Data Source
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AI summary
The present invention overcomes deficiencies of existing line-calling devices by leveraging a single fixed-location camera to identify object state conditions that resolve object-tracking problems that otherwise require multi-camera or moving-camera solutions. Though described in the context of an automated tennis line-calling device, the invention is equally applicable to other object-tracking problems that can be resolved by identifying object state conditions without employing moving or multiple cameras. The tennis line-calling device is attached to (or at least located in proximity to) the net post of a tennis court, thereby enabling a "close-up" view of both static (court lines) and moving (ball, players, etc.) objects. In one embodiment, integration of a video camera system with line-calling functionality provides additional benefits, including attachment of a single turnkey device to any tennis net post so as to provide automated line-calling functionality without the need for any external video cameras or processing functionality.