Method and apparatus for separation of impulsive and non-impulsive components in a signal
First Claim
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1. A method of separating impulsive and non-impulsive signal components in a time-domain signal, comprising the steps of:
- decomposing said time-domain signal using a wavelet transform to produce a plurality of sets of wavelet coefficients, each set of wavelet coefficients corresponding to a respective time/frequency span;
determining a respective kurtosis value for each set of wavelet coefficients wherein said kurtosis value is determined for each of the wavelet coefficient sets as a function of the coefficient values within each wavelet coefficient set; and
re-synthesizing a new time-domain signal using an inverse wavelet transform applied to selected ones of said sets of wavelet coefficients, said selected ones being selected in response to said respective kurtosis values.
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Abstract
Impulsive components and non-impulsive components within any time-domain signal such as audio, video, vibration, etc., are separated using wavelet analysis and sorting of wavelet coefficient sets according to statistical parameters of each respective coefficient set. Each entire coefficient set is either included or excluded from each respective separated component based on the statistical parameter. Thus, automatic, adaptive, flexible, and reliable separation of impulsive and non-impulsive components is achieved.
38 Citations
12 Claims
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1. A method of separating impulsive and non-impulsive signal components in a time-domain signal, comprising the steps of:
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decomposing said time-domain signal using a wavelet transform to produce a plurality of sets of wavelet coefficients, each set of wavelet coefficients corresponding to a respective time/frequency span;
determining a respective kurtosis value for each set of wavelet coefficients wherein said kurtosis value is determined for each of the wavelet coefficient sets as a function of the coefficient values within each wavelet coefficient set; and
re-synthesizing a new time-domain signal using an inverse wavelet transform applied to selected ones of said sets of wavelet coefficients, said selected ones being selected in response to said respective kurtosis values. - View Dependent Claims (2, 3)
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4. A method of removing non-impulsive signal components from a time-domain signal, comprising the steps of:
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decomposing said time-domain signal using a wavelet transform to produce a plurality of sets of wavelet coefficients, each set of wavelet coefficients corresponding to a respective time/frequency span;
determining a respective kurtosis value for each set of wavelet coefficients wherein said kurtosis value is determined for each of the wavelet coefficient sets as a function of the coefficient values within each wavelet coefficient set;
comparing each respective kurtosis value with a predetermined kurtosis threshold; and
re-synthesizing a new time-domain signal using an inverse wavelet transform applied to selected ones of said sets of wavelet coefficients for which said respective kurtosis values are greater than said predetermined kurtosis threshold.
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5. A method of removing impulsive signal components from a time-domain signal, comprising the steps of:
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decomposing said time domain signal using a wavelet transform to produce a plurality of sets of wavelet coefficients, each set of wavelet coefficients corresponding to a respective time/frequency span;
determining a respective kurtosis value for each set of wavelet coefficients wherein said kurtosis value is determined for each of the wavelet coefficient sets as a function of the coefficient values within each wavelet coefficient set;
comparing each respective kurtosis value with a predetermined kurtosis threshold; and
re-synthesizing a new time-domain signal using an inverse wavelet transform applied to selected ones of said sets of wavelet coefficients for which said respective kurtosis values are less than said predetermined kurtosis threshold.
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6. Apparatus for impulsive and non-impulsive signal separation of an input signal, comprising:
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a wavelet transformer decomposing said input signal into a plurality of wavelet coefficient sets;
a kurtosis value calculator calculating a kurtosis value for each wavelet coefficient set wherein said kurtosis value is determined for each of the wavelet coefficient sets as a function of the coefficient values within each wavelet coefficient set;
a classifier identifying an impulsive group of wavelet coefficient sets and a non-impulsive group of wavelet coefficient sets in response to said kurtosis values; and
an inverse wavelet transformer for synthesizing an output signal from one of said groups of wavelet coefficient sets. - View Dependent Claims (7, 8)
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9. Apparatus for removing background noise from an input signal, comprising:
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a data memory storing samples of said input signal;
a wavelet transformer coupled to said data memory decomposing said samples of said input signal into a plurality of wavelet coefficient sets;
a kurtosis value calculator calculating a kurtosis value for each wavelet coefficient set wherein said kurtosis value is determined for each of the wavelet coefficient sets as a function of the coefficient values within each wavelet coefficient set;
a classifier comparing respective kurtosis values calculated for each respective wavelet coefficient set with a predetermined kurtosis threshold; and
an inverse wavelet transformer for synthesizing an output signal including substantially only those wavelet coefficient sets for which said respective kurtosis values are not less than said predetermined kurtosis threshold, whereby said output signal represents said input signal with background noise removed. - View Dependent Claims (10, 11, 12)
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Specification