Method and apparatus for the determination of the mass of an impacting object
First Claim
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1. A method of detecting the mass of an impacting object behind a wall comprising the steps of:
- deriving an electric signal representative of an acoustic signal generated by the impact of said object;
converting said electric signal into a frequency spectrum signal;
comparing said frequency spectrum signal with a set of reference data each having a frequency spectrum indicative of the mass of an impacting sample for identifying matching with reference data from said set having the same relative importance in the spectrum; and
providing an indication of the mass associated with such matching reference data which is indicative of the mass of said impacting object.
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Abstract
The impact signal derived from an acoustic transducer has a unique signature represented by its frequency spectrum. The present invention generates under predetermined conditions with objects, each of definite weight and form, a series of impact signals for reference purposes and correlates an actual impact signal from an unknown impacting object with such reference impact signals by comparing the frequency spectra, thereby to indirectly recognize the impacting object.
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6 Claims
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1. A method of detecting the mass of an impacting object behind a wall comprising the steps of:
- deriving an electric signal representative of an acoustic signal generated by the impact of said object;
converting said electric signal into a frequency spectrum signal;
comparing said frequency spectrum signal with a set of reference data each having a frequency spectrum indicative of the mass of an impacting sample for identifying matching with reference data from said set having the same relative importance in the spectrum; and
providing an indication of the mass associated with such matching reference data which is indicative of the mass of said impacting object.
- deriving an electric signal representative of an acoustic signal generated by the impact of said object;
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2. Apparatus for the detection of the mass of an impacting object behind a wall comprising:
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acoustic means coupled with said wall for deriving at least one impact time signal representative of a true impact by said object; means for converting said time signal into a frequency spectrum signal; means for detecting similarity between said frequency spectrum signal and one of a plurality of spectrum reference data, with such similarity being the relative importance of the spectrum frequency components, said reference data being such associated with a definite mass of an impacting mass; and means for deriving an indication of mass associated with said one of said reference data of said set as representative of the actual mass of said impacting object. - View Dependent Claims (3, 4, 5, 6)
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Specification