Method and apparatus for distinguishing metal objects employing multiple frequency interrogation
US6879161B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 11, 2002 |
| Grant date | Apr 12, 2005 |
| Priority date | — |
| Expiry date | Sep 29, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/104
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for distinguishing metal objects employing multiple frequency interrogation. In one aspect, the method includes interrogating a target with at least two frequencies, obtaining respective response signals for the two frequencies, resolving the response signals into at least respective resistive component portions, comparing the magnitudes of at least two of the resistive component portions, selecting one response signal from among the response signals based on the comparison, and characterizing the target with the selected response signal. In other aspects, the method includes obtaining response data by interrogating the target at at least two frequencies, normalizing the response data and comparing the normalized response data. A signal is provided indicating the extent of any disagreement in the normalized response data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.