Method for detecting the presence of a ferromagnetic object using maximum and minimum magnetic field data
First Claim
1. A method for detecting a presence or an absence of a ferromagnetic object within a sensing area, comprising:
- sensing, during a sample time, a magnetic field adjacent the sensing area;
producing surveillance data representative of the sensed magnetic field during the sample time;
determining an absolute value difference between a maximum datum and a minimum datum comprising the surveillance data; and
determining whether the absolute value difference has a positive sign or a negative sign based upon a determined relative order of occurrence of the maximum datum and minimum datum, the absolute value difference between the maximum datum and the minimum datum and the corresponding positive or negative sign comprising a representative surveillance datum, the representative surveillance datum being indicative of the presence or absence of the ferromagnetic object within the sensing area.
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Accused Products
Abstract
A method for detecting a presence or an absence of a ferromagnetic object within a sensing area may comprise the steps of sensing, during a sample time, a magnetic field adjacent the sensing area; producing surveillance data representative of the sensed magnetic field; determining an absolute value difference between a maximum datum and a minimum datum comprising the surveillance data; and determining whether the absolute value difference has a positive or negative sign. The absolute value difference and the corresponding positive or negative sign thereof forms a representative surveillance datum that is indicative of the presence or absence in the sensing area of the ferromagnetic material.
86 Citations
13 Claims
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1. A method for detecting a presence or an absence of a ferromagnetic object within a sensing area, comprising:
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sensing, during a sample time, a magnetic field adjacent the sensing area; producing surveillance data representative of the sensed magnetic field during the sample time; determining an absolute value difference between a maximum datum and a minimum datum comprising the surveillance data; and determining whether the absolute value difference has a positive sign or a negative sign based upon a determined relative order of occurrence of the maximum datum and minimum datum, the absolute value difference between the maximum datum and the minimum datum and the corresponding positive or negative sign comprising a representative surveillance datum, the representative surveillance datum being indicative of the presence or absence of the ferromagnetic object within the sensing area. - View Dependent Claims (2)
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3. A method for detecting a presence or an absence of a ferromagnetic object within a sensing area, comprising:
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providing a first magnetic field sensor positioned at a first location adjacent the sensing area, the first magnetic field sensor producing first surveillance data representative of a first sensed magnetic field; providing a second magnetic field sensor positioned at a second location adjacent the sensing area, the second magnetic field sensor producing second surveillance data representative of a second sensed magnetic field; sensing, during a sample time, the first and second magnetic fields; determining, for the first and second surveillance data, an absolute value difference between a maximum datum and a minimum datum; and determining whether the absolute value difference for the first and second surveillance data has a positive sign or a negative sign based upon a determined relative order of occurrence of the maximum datum and minimum datum, the absolute value differences and corresponding positive or negative signs comprising representative surveillance data, the representative surveillance data being indicative of the presence or absence of the ferromagnetic object within the sensing area. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification