Method for the compression of recordings of ambient noise, method for the detection of program elements therein, and device thereof
First Claim
1. A method for storing an electric signal representing recorded ambient noise in compressed form, the method comprising:
- periodically recording samples of the ambient noise using a sound transducer, the sample duration being shorter than the sampling cycle;
dividing the recorded audio signal into at least two band signals by filtering, with each one of the band signals containing a frequency range of the audio signal, and wherein any content of the other band signals contained in each band signal is present only in an attenuated form;
normalizing the amplitude of the divided audio signal within a first predetermined range D;
mapping the normalized amplitude values of the sampled ambient noise onto a second predetermined range of values in the time domain using a non-linear mapping function to obtain an emphasis of selected values ranges within the first or the second predetermined ranges; and
storing the mapped result in an electronic memory in a digital format.
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Accused Products
Abstract
The amount of data produced in the process of recording even short hearing samples by means of a monitor (1) may be considerably reduced by effecting a normalization to a range of values D and a subsequent nonlinear mapping to a second, preferably smaller range of values W. The result may be stored in an electronic memory. Further preferred measures are the spitting of the hearing samples into e.g. 6 signals each of which contains a respective frequency band of the original signal, and the conversion of the original amplitude values into energy variation values with simultaneous low pass filtering. Preferably, all cited processing steps are performed by a signal processor (9). A continuous recording time of up to 14 days by a monitor in the form of a wristwatch can thus be attained with state-of-the-art technology.
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Citations
33 Claims
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1. A method for storing an electric signal representing recorded ambient noise in compressed form, the method comprising:
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periodically recording samples of the ambient noise using a sound transducer, the sample duration being shorter than the sampling cycle; dividing the recorded audio signal into at least two band signals by filtering, with each one of the band signals containing a frequency range of the audio signal, and wherein any content of the other band signals contained in each band signal is present only in an attenuated form; normalizing the amplitude of the divided audio signal within a first predetermined range D; mapping the normalized amplitude values of the sampled ambient noise onto a second predetermined range of values in the time domain using a non-linear mapping function to obtain an emphasis of selected values ranges within the first or the second predetermined ranges; and storing the mapped result in an electronic memory in a digital format. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for storing an electric signal representing recorded ambient noise in compressed form, the method comprising:
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periodically recording samples of the ambient noise using a sound transducer, the sample duration being shorter than the sampling cycle; normalizing the amplitude of a signal output of the transducer or a signal derived therefrom within a first predetermined range D; mapping the normalized amplitude values of the sampled ambient noise onto a second predetermined range of values in the time domain using a non-linear mapping function to obtain an emphasis of selected values ranges within the first or the second predetermined ranges; and storing the mapped result in an electronic memory in a digital format; and generating an energy signal which is proportional to an energy content of the ambient noise from the audio signal or from a signal derived from the audio signal. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method for storing an electric signal representing recorded ambient noise in compressed form, the method comprising:
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periodically recording samples of the ambient noise using a sound transducer, the sample duration being shorter than the sampling cycle; normalizing the amplitude of a signal output of the transducer or a signal derived therefrom within a first predetermined range D; mapping the normalized amplitude values of the sampled ambient noise onto a second predetermined range of values in the time domain using a non-linear mapping function to obtain an emphasis of selected values ranges within the first or the second predetermined ranges; and storing the mapped result in an electronic memory in a digital format;
wherein;the range of normalized values D is defined by a lower limit Du, and an upper limit Do, and the normalization is effected by; obtaining the maximum of the absolute value of the audio signal or the derived signal within the duration of normalizing the audio or derived signal, which is shorter than or equal to the duration of a hearing sample, multiplying the reciprocal value of said maximum by (Do−
Du+1), andmultiplying this product by each value of the audio or derived signal within the duration of the normalized signal. - View Dependent Claims (30, 31, 32, 33)
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Specification