US 5,592,401 · Granted 1997-01-07
The Sensor Fusion Patent That Lets Coaches Track Athletic Moves in Real-Time
Imagine trying to track a baseball pitcher's arm motion with a camera (accurate but slow) or an accelerometer (super fast but drifts). This patent combines multiple imperfect sensors to get the best of both worlds: speed AND accuracy. By blending delayed sensors, fast sensors, and unreliable-but-sometimes-brilliant sensors, you can capture live athletic movement with precision.
The plain-English version
What it protects
The claim covers a system that combines at least three different types of position sensors—some that are accurate but slow to respond, some that respond quickly but drift over time, and some that are accurate for a while but unreliable overall—and uses logic to blend their outputs into a single accurate, real-time position signal. What's protected here is the method of picking which sensor to trust at which moment to eliminate the weaknesses of each one alone.
Why it matters
In the mid-1990s, motion capture and sports analysis relied on single-sensor solutions, each with trade-offs. This patent solved a real engineering problem: how to get live, accurate feedback during fast human movement (athletics, music, dance) without the lag or drift that made earlier systems useless for real-time coaching. The fusion approach became foundational to modern motion analysis systems used in sports training, physical therapy, and performance capture.
Real-world use
A baseball coach using a motion-capture system to analyze a pitcher's throwing mechanics in real-time, or a physical therapist tracking a patient's knee bend during rehabilitation without waiting for slow sensor data.
Original USPTO abstract
In accordance with the subject invention, devices and methods are provided for the accurate reporting of movement of an entity. Sensors which are accurate, but provide a delayed signal ("delayed signal sensors"), which delay is unacceptable for many applications, may be used in conjunction with fast sensors ("fast signal sensors"), which are usually subject to drift and other inaccuracies in providing information about a position. Additional sensors which may provide even more accurate and/or less signal sensor delay for a period of time, but which sensor signal is subject to periods of interrupted or undesirable output thereby making it unreliable ("unreliable signal sensors") may also be used in combination with one or more of the delayed signal sensors and fast signal sensors. By using a combination of such sensors, accurate, reliable position information is rapidly obtained to allow high-resolution and/or real-time analysis and depictions of movement. Complex rapid movements associated with athletics, music, and other rapid activities can be monitored in real-time to provide accurate information during the movement. Such information may then be used to analyze the movement, for instruction for improvement, for repeating the activity in a virtual setting and the like.
Patent details
- Publication number
- US 5,592,401
- Filing date
- 1995-02-28
- Grant date
- 1997-01-07
- Assignee
- Virtual Technologies, Inc.
- Inventor(s)
- KRAMER; JAMES F.
- CPC class
- G06F3/011
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