Difference correcting method for posture determining instrument and motion measuring instrument
US7233872B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 2004 |
| Grant date | Jun 19, 2007 |
| Priority date | — |
| Expiry date | Feb 16, 2024 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B2562/0219
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
The error of a sensor in motion capture system is corrected. An acceleration sensor determines the direction of gravity (G1) in a still initial state. The direction G1 will never change always if a drift dose not occur. However, actually if an object to which an acceleration sensor is attached moves along a coordinate axis, the direction gradually changes due to a drift with time. According to the invention, after a given time has passed, the acceleration sensor is stopped to determine the direction of gravity. Referring to the data on this determination, the true direction of gravity to be judged is compared with the direction of gravity G1 influenced by the drift. The difference between them is assumed to be an error due to a drift, and the error is subtracted from the determined value to correct the error of the measurement value. Similarly to the direction of gravity, assuming that there is an error in any direction in the coordinate system, the errors are corrected, and more accurate motion determination is possible.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.