| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electromagnetic position determining/tracking system in which problems of interfering are solved. <P>SOLUTION: The apparatus is provided for tracking an object in a body of a patient in the presence of an interfering article. A set of one or more radiators generate an energy field at a fundamental frequency in a vicinity of the object. A position sensor, fixed to the object, generates a signal in response to the energy field. A control unit has access to a database of one or more harmonic frequency patterns associated with one or more respective specific types of interfering articles. The control unit (a) receives the signal, (b) detects a pattern of harmonic frequencies of the fundamental frequency present in the signal in response to an interaction of the interfering article with the energy field, (c) compares the pattern with harmonic frequency patterns stored in the database, (d) identifys the interfering article by the comparison, (e) corrects the signal in response to the identification of the interfering article and a magnitude of one or more of the harmonic frequencies in the detected pattern, and (f) determines position coordinates of the object in response to the corrected signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
