Glass breakage detector
First Claim
1. A glass breakage detection device comprising:
- a) an acoustic transducer for sensing acoustic waves and for providing an analog signal representative of the received acoustic waves, b) means for converting said analog signal to a digital signal, c) means for filtering said digital signal to produce a filtered digital signal, said means for filtering comprising;
i) means for multiplying said digital signal by a filter coefficient to produce a multiplied digital signal, ii) means for shifting said multiplied digital signal to produce a shifted digital signal, iii) means for accumulating said shifted digital signal to produce said filtered digital signal, and d) means for processing said filtered digital signal in accordance with a first algorithm stored in memory to determine if said received acoustic waves are a result of glass breakage.
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Abstract
A method and a device for detecting the breakage of glass. A glass breakage detector that uses an acoustic transducer, an analog-to-digital converter, and a processing means which uses software algorithms to determine if a signal received by the acoustic transducer is a result of glass breaking. The glass breakage detector also uses amplifiers which have a greater gain response for higher frequency components in the received signal. The glass breakage detector is also able to correct the offset error generated by the amplifiers. The processing means or digital signal processor (DSP) uses a feature extraction software algorithm that extracts characteristics of the received sound using a plurality of filters centered at different frequencies and a rules analysis software algorithm to compare the extracted features to features from glass breakage and false alarms. The DSP is also capable of transmitting the extracted features to an external computing device for further analysis. The DSP may use different software routines which may be selected by a user to process the signal from the acoustic transducer. The software algorithms used by the DSP may be modified or customized for optimally detecting a glass breakage event.
36 Citations
35 Claims
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1. A glass breakage detection device comprising:
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a) an acoustic transducer for sensing acoustic waves and for providing an analog signal representative of the received acoustic waves, b) means for converting said analog signal to a digital signal, c) means for filtering said digital signal to produce a filtered digital signal, said means for filtering comprising;
i) means for multiplying said digital signal by a filter coefficient to produce a multiplied digital signal, ii) means for shifting said multiplied digital signal to produce a shifted digital signal, iii) means for accumulating said shifted digital signal to produce said filtered digital signal, and d) means for processing said filtered digital signal in accordance with a first algorithm stored in memory to determine if said received acoustic waves are a result of glass breakage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for detecting glass breakage comprising the steps of:
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a) sensing an acoustic wave with a transducer to produce an analog signal, b) converting said analog signal to a digital signal, c) filtering said digital signal to produce a filtered digital signal, wherein said filtering comprises the steps of;
i) multiplying said digital signal by a filter coefficient to produce a multiplied digital signal, ii) shifting said multiplied digital signal to produce a shifted digital signal, iii) accumulating said shifted digital signal to produce said filtered digital signal, and d) processing said filtered digital signal in accordance with a first algorithm stored in memory to determine if said acoustic wave is a result of glass breakage. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A processing device comprising:
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a) means for receiving a signal correlated to an acoustic wave detected by a transducer, b) means for filtering said signal to produce a filtered signal, said means for filtering comprising;
i) means for multiplying said signal by a filter coefficient to produce a multiplied signal, ii) means for shifting said multiplied signal to produce a shifted signal, iii) means for accumulating said shifted signal to produce said filtered signal, and c) means for processing said filtered signal in accordance with an algorithm stored in memory to determine if said signal is the result of glass breakage. - View Dependent Claims (30)
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31. A glass breakage detection device comprising:
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a) an acoustic transducer for sensing acoustic waves and for providing an analog signal representative of the received acoustic waves, b) means for converting said analog signal to a digital signal, c) means for processing said digital signal in accordance with a first algorithm stored in memory to determine if said received acoustic waves are a result of glass breakage, and d) input means for allowing a user to modify said first algorithm. - View Dependent Claims (32, 33, 34, 35)
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Specification