Method and apparatus for monitoring a structure
AssigneeFuture Fibre Technologies Pty Ltd
InventorsSeedahmed Mahmoud, Colin Kemp, Alexander Adams, Jim Katsifolis
Life of this patent
Estimating the term…
Abstract
A system and method for monitoring a structure and for distinguishing between an alarm condition, and a nuisance event such as rain. An optical fibre sensor (20,22) produces a signal indicative of a disturbance and level crossing rates are determined to distinguish between noise in the signal (nuisance event) and a required event. A FFT technique is also disclosed as well as classification of an event by extracting predetermined features from the signal.
Claims57
An apparatus for monitoring a structure comprising:
- a sensing device for producing a detected signal for determining a change in or to the structure;
- a processor for processing the detected signal to determine level crossing rates in the signal and, from those rates, distinguishing between noise in the signal indicative of a nuisance event and a required event;
- wherein the sensing device comprises:
- a light source;
- a waveguide for receiving light from the light source so that light is caused to propagate through the waveguide;
- and
- a detector for detecting the light propagating through the waveguide to determine a change in the monitored structure, and for producing the detected signal.
An apparatus for monitoring a structure comprising:
- a sensing device for producing a detected signal for determining a change in or to the structure;
- a processor for processing the detected signal to determine level crossing rates in the signal and, from those rates, distinguishing between noise in the signal indicative of a nuisance event and a required event;
- wherein the processor is for defining a plurality of block durations of a predetermined time interval, setting a noise level threshold, monitoring the number of level crossings exceeding the noise level threshold per block duration for a predetermined noise detection duration period comprised of a number of block durations, setting a noise amplitude variation being a predetermined number of level crossings per block, so that if the number of level crossings in a noise detection duration does not vary by more than the noise amplitude variation, the signal over the noise detection duration period is regarded as a nuisance event.
A method of monitoring a structure comprising:
- monitoring a change in the structure by a sensing device to provide a detected signal;
- and
- processing the detected signal to determine level crossing rates and for distinguishing between a nuisance event and a required event based on the level crossing rates.
A system for monitoring a structure comprising:
- a sensing device for producing a detected signal for determining a change in or to the structure;
- and
- a processor for processing the signal detected by the detector to distinguish between nuisance events and the required event, the processor establishing an event threshold and dynamically varying the event threshold dependent upon a nuisance signal level in the detected signal so that in order to determine a required event the signal detected by the detector exceeds the dynamic event threshold.
A method of monitoring a structure comprising:
- monitoring a change in the structure by a sensing device to provide a detected signal;
- and
- establishing an event threshold and dynamically varying the event threshold dependent upon a nuisance signal level in the detected signal so that in order to determine a required event the signal detected by the detector exceeds the dynamic event threshold.
An apparatus for monitoring a structure comprising:
- a sensing device for producing a detected signal for determining a change in or to the structure;
- and
- a processor for producing from said detected signal a signal indicative of a combined nuisance event and required event, and a signal indicative of only the nuisance event, the processor being for performing a fast Fourier transform on both signals to convert the signals to the frequency domain, removing selected frequencies in the signal indicative of only the nuisance event from the combined nuisance and event signal to produce a signal containing only event data to enable the presence of a required alert event to be determined.
A method of monitoring a structure comprising:
- monitoring a change in the structure by a sensing device to provide a detected signal;
- and
- producing from said detected signal a signal indicative of a combined nuisance event and required event, and a signal indicative of only the nuisance event, the processor being for performing a fast Fourier transform on both signals to convert the signals to the frequency domain, removing selected frequencies in the signal indicative of only the nuisance event from the combined nuisance and event signal to produce a signal containing only event data to enable the presence of a required alert event to be determined.
An apparatus for monitoring a structure to determine the occurrence of a required event, comprising:
- a sensing device for producing a detected signal for determining a change in or to the structure;
- and
- a processor for processing the detected signal and extracting predetermined features from the detected signal so that the classification of an event type can be determined from the predetermined features.
A method of monitoring a structure to determine the occurrence of a required event, comprising:
- monitoring a change in the structure by a sensing device to provide a detected signal;
- and
- processing the detected signal and extracting predetermined features from the detected signal so that the classification of an event type can be determined from the predetermined features.
Dependencies are inferred from the claim text.