US7353125B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Eddy current detection and compensation
Assignee: Bank of Montreal
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Filing: 2006-01-13
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Granted: 2008-04-01
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Expires: 2026-01-13
Abstract
Abstract A distortion compensation method includes determining an undisturbed phase for at least one of a first position indication signal and a second position indication signal. The method includes determining an undisturbed ratio that relates the amplitude of the first position indication signal at a first frequency to the amplitude of the second position indication signal at a second frequency. The method also includes determining a disturbed amplitude of the position indication signal and adjusting a position indication based on the disturbed amplitude and phase, the undisturbed amplitude ratio, and the undisturbed phase. The method further comprises determining a relationship between the eddy current phase of the first position indication signal and the second position indication signal.
Inventors
- 👤 John M. Nieminen
- 👤 Stefan R. Kirsch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:51
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/72; G01N27/82; G01N27/90; A; A61; A61B; A61B34/00; A61B34/20; A61B5/00; A61B5/06; A61B5/061; A61B5/062; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/54; G01R33/56; G01R33/565; A61B2034/2046; A61B2034/2051
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
83 words
A method for detecting the presence of conductive objects, the method comprising: determining a characteristic frequency function of an undisturbed magnetic tracking system; measuring a disturbed real-time frequency function; calculating real and imaginary components of the position indication signal using a chi-squared minimization of the disturbed frequency function to the undisturbed frequency function; calculating a chi-squared value based on the characteristic frequency function and the disturbed frequency function; and monitoring the chi-squared value to detect changes indicating the presence of a conductive object.
Claim 2
Independent Claim
83 words
A method for detecting the presence of conductive objects, the method comprising: determining a characteristic frequency function of an undisturbed magnetic tracking system; measuring a disturbed real-time frequency function; calculating real and imaginary components of the position indication signal using a chi-squared minimization of the disturbed frequency function to the undisturbed frequency function; calculating a chi-squared value based on the characteristic frequency function and the disturbed frequency function; and monitoring the chi-squared value to detect changes indicating the presence of a conductive object.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein determining the characteristic frequency function includes determining the characteristic frequency function based on undisturbed position indication signals.
Claim 4
Dependent Claim
18 words
The method of claim 1 further comprising monitoring the chi-squared value for a plurality of position indication signals.
Claim 5
Dependent Claim
29 words
The method of claim 3 wherein detecting a change in the chi-squared value of at-least one of the plurality of position indication signals indicates the presence of conductive objects.
Claim 6
Dependent Claim
19 words
The method of claim 1 further comprising determining, calculating, and monitoring the chi-squared value for a plurality of frequencies.
Claim 7
Dependent Claim
31 words
The method of claim 5 wherein the detection of a change in a chi-squared value at a particular frequency range can indicate the presence of a particular type of conductive objects.
Claim 8
Dependent Claim
14 words
The method of claim 6 wherein the particular frequency range is a mid-frequency range.
Claim 9
Dependent Claim
14 words
The method of claim 6 wherein the particular frequency range is a low-frequency range.
Claim 10
Dependent Claim
14 words
The method of claim 6 wherein the particular frequency range is a high-frequency range.
Claim 11
Dependent Claim
27 words
The method of claim 6 further comprising determining the position indication signal in a frequency range that is not affected by a particular type of conductive object.
Claim 12
Independent Claim
85 words
A system for detecting the presence of conductive objects, the system being configured to: determine a characteristic frequency function of an undisturbed magnetic tracking system; measure a disturbed real-time frequency function; calculate real and imaginary components of the position indication signal using a chi-squared minimization of the disturbed frequency function to the undisturbed frequency function; calculate a chi-squared value based on the characteristic frequency function and the disturbed frequency function; and monitor the chi-squared value to detect changes indicating the presence of a conductive object.
Claim 13
Independent Claim
85 words
A system for detecting the presence of conductive objects, the system being configured to: determine a characteristic frequency function of an undisturbed magnetic tracking system; measure a disturbed real-time frequency function; calculate real and imaginary components of the position indication signal using a chi-squared minimization of the disturbed frequency function to the undisturbed frequency function; calculate a chi-squared value based on the characteristic frequency function and the disturbed frequency function; and monitor the chi-squared value to detect changes indicating the presence of a conductive object.
Claim 14
Dependent Claim
23 words
The system of claim 11 wherein the system is further configured to determine the characteristic frequency function based on undisturbed position indication signals.
Claim 15
Dependent Claim
23 words
The system of claim 11 wherein the system is further configured to monitor the chi-squared value for a plurality of position indication signals.
Claim 16
Dependent Claim
24 words
The system of claim 11 wherein the system is further configured to determine, calculate, and monitor the chi-squared value for a plurality of frequencies.
Claim 17
Dependent Claim
32 words
The system of claim 11 wherein the system is further configured to determine the position indication signal in a frequency range that is not affected by a particular type of conductive object.
References Cited (Backward Citations)
EP0228056A2
Cited
US4829250A
Cited
US5629626A
Cited
US5767669A
Cited
EP0993804A1
Cited
US6427079B1
Cited
US6172499B1
Cited
US6624626B2
Cited
WO2002008793A1
Cited
EP1203560A2
Cited
US20050222625A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2011-04-01 | 2011-10-01 | 2012-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2015-04-01 | 2015-10-01 | 2016-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2019-04-01 | 2019-10-01 | 2020-04-01 | $7700.00 | Window Closed / Lapsed |