Theft-prevention system and method with magnetic field detection

An electronic theft prevention system, comprising:

• a first magnetometer arranged in a first station and configured to output a first vector signal (vs1) representing movement of a first magnetic field vector;
• a second magnetometer arranged in a second station and configured to output a second vector signal (vs2) representing movement of a second magnetic field vector;
• a third magnetometer arranged in a third station and configured to output a third vector signal representing a third magnetic field vector;
• a signal processor coupled to receive the first vector signal, the second vector signal, and the third vector signal, and configured for:
• detecting a corresponding movement of the first magnetic field vector and the second magnetic field vector;
• subsequent to the detecting the corresponding movement of the first magnetic field vector and the second magnetic field vector, detecting commencement and continuance of fluctuation of the first magnetic field vector, wherein continuance of the fluctuation is determined in accordance with a timing criterion;
• detecting a corresponding movement of the third magnetic field and the first magnetic field vector;
• subsequent to and in the affirmative event of the detecting the corresponding movement of the third magnetic field vector and the first magnet field vector, determining commencement and continuance of fluctuation of the third magnetic field vector;
• wherein continuance of the fluctuation of the third magnetic field vector is determined subject to a second timing criterion;
• determining whether to raise or forgo to raise an alarm that warns about a possible theft-related event in response to at least the determination of commencement and continuance of fluctuation of at least the third magnetic field vector, the first magnetic field vector or the second magnetic field vector.

An electronic theft prevention system, comprising:

• a first magnetometer arranged in a first station and configured to output a first vector signal (vs1) representing movement of a first magnetic field vector;
• a second magnetometer arranged in a second station and configured to output a second vector signal (vs2) representing movement of a second magnetic field vector wherein the first station and the second station are installed 0.5 to 1.5 meters above a floor level;
• and
• a signal processor coupled to receive the first vector signal and the second vector signal, and configured for:
• detecting a corresponding movement of the first magnetic field vector and the second magnetic field vector;
• subsequent to the detecting the corresponding movement of the first magnetic field vector and the second magnetic field vector, detecting commencement and continuance of fluctuation of the first magnetic field vector, wherein continuance of the fluctuation is determined in accordance with a timing criterion;
• and
• determining whether to raise or forgo to raise the alarm that warns about a possible theft-related event in response to at least the determining of commencement and continuance of fluctuation of the first magnetic field vector.

A method of detecting a theft-related event, comprising:

• acquiring first vector values representing movement of a first magnetic field vector by a first multi-axis magnetometer arranged in a first station;
• acquiring second vector values representing movement of a second magnetic field vector by a second multi-axis magnetometer arranged in a second station;
• detecting a corresponding movement of the first magnetic field vector and the second magnetic field vector;
• subsequent to and in the affirmative event of the detecting the corresponding movement of the first magnetic field vector and the second magnetic field vector, detecting a pulse in one or both of the first vector signal and the second vector signal and in response thereto increasing a counter and starting a timer;
• and in response thereto:
• determining whether the timer has reached a timeout time;
• and in the affirmative event thereof, decreasing the counter;
• determining whether the counter has reached a counter threshold;
• and in the affirmative event thereof, enabling an alarm;
• and
• determining whether to raise or forgo to raise the alarm that warns about a possible theft-related event.

A data processing system comprising:

• a processor;
• a first multi-axis magnetometer arranged in a first station and in communication with the processor;
• a second multi-axis magnetometer arranged in a second station and in communication with the processor;
• a memory in communication with the processor, wherein the memory has stored therein a computer readable code that when executed by the processor the following method is performed:
• acquiring first vector values representing movement of a first magnetic field vector by the first multi-axis magnetometer;
• acquiring second vector values representing movement of a second magnetic field vector by the second multi-axis magnetometer;
• detecting a corresponding movement of the first magnetic field vector and the second magnetic field vector;
• subsequent to and in the affirmative event of the detecting the corresponding movement of the first magnetic field vector and the second magnetic field vector, detecting a pulse in one or both of the first vector signal and the second vector signal and in response thereto increasing a counter and starting a timer;
• and in response thereto:
• determining whether the timer has reached a timeout time;
• and in the affirmative event thereof, decreasing the counter;
• determining whether the counter has reached a counter threshold;
• and in the affirmative event thereof, enabling an alarm;
• and
• determining whether to raise or forgo to raise an alarm that warns about a possible theft-related event.

A non-transitory computer medium comprising program code adapted to cause a data processing system to perform the method of:

• acquiring first vector values representing movement of a first magnetic field vector by a first multi-axis magnetometer arranged in a first station;
• acquiring second vector values representing movement of a second magnetic field vector by a second multi-axis magnetometer arranged in a second station;
• detecting a corresponding movement of the first magnetic field vector and the second magnetic field vector;
• subsequent to and in the affirmative event of the detecting the corresponding movement of the first magnetic field vector and the second magnetic field vector, detecting a pulse in one or both of the first vector signal and the second vector signal and in response thereto increasing a counter and starting a timer;
• and in response thereto:
• determining whether the timer has reached a timeout time;
• and in the affirmative event thereof, decreasing the counter;
• determining whether the counter has reached a counter threshold;
• and in the affirmative event thereof, enabling an alarm;
• and
• determining whether to raise or forgo to raise an alarm that warns about a possible theft-related event.