Method and apparatus for processing a sound signal
First Claim
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1. A method for processing a sound signal, said method comprising the steps of:
- transforming said sound signal into the frequency domain;
determining an envelope of the transformed sound signal over a time period for at least one prescribed frequency;
subdividing the envelope into a first number of segments each determined by a prescribed duration;
determining a maximum of the envelope for each segment of the first number of segments;
determining a smallest maximum of said determined maximums for a second number of segments of said first number of segments;
weighting the smallest maximum by a factor; and
processing the sound signal by subtracting the weighted smallest maximum from the sound signal.
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Abstract
A method and an apparatus for processing a sound signal in which a useful signal and an interference signal are specified, the sound signal being transformed into the frequency domain and a change in the profile of the frequency being represented by an envelope for at least one frequency over a time. By segmenting the envelope, a maximum is obtained for each segment, the smallest maximum, weighted by a factor, being subtracted from the sound signal. It is also possible to take account of the minimum for the purpose of reducing the interference signal.
11 Citations
8 Claims
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1. A method for processing a sound signal, said method comprising the steps of:
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transforming said sound signal into the frequency domain;
determining an envelope of the transformed sound signal over a time period for at least one prescribed frequency;
subdividing the envelope into a first number of segments each determined by a prescribed duration;
determining a maximum of the envelope for each segment of the first number of segments;
determining a smallest maximum of said determined maximums for a second number of segments of said first number of segments;
weighting the smallest maximum by a factor; and
processing the sound signal by subtracting the weighted smallest maximum from the sound signal. - View Dependent Claims (2, 3, 4, 5, 6)
determining a minimum for a third number of segments of the first number of segments; and
combining the smallest maximum with the minimum, and wherein the sound signal is processed by the subtracting the combined smallest maximum and minimum from the sound signal.
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3. The method as claimed in claim 2, wherein the weighted smallest maximum and the minimum are combined in accordance with the following relationship:
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wherein a is a first prescribed coefficient, b is a second prescribed coefficient, max is the smallest maximum, and min is the minimum.
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4. The method as claimed in claim 2, wherein the sound signal is processed in each case after the second number of segments or the third number of segments has elapsed.
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5. The method as claimed in claim 1, wherein the sound signal is a voice signal.
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6. The method as claimed in claim 1, wherein the processed sound signal is for voice recognition purposes.
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7. An apparatus for processing a sound signal comprising:
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a processor unit for;
transforming said sound signal into the frequency domain;
determining an envelope of the transformed sound signal over a time period for at least one prescribed frequency;
subdividing the envelope into a first number of segments each determined by a prescribed duration;
determining a maximum of the envelope for each segment of the first number of segments;
determining a smallest maximum of said determined maximums for a second number of segments of said first number of segments;
weighting the smallest maximum by a factor; and
processing the sound signal by subtracting the weighted smallest maximum from the sound signal. - View Dependent Claims (8)
determining a minimum for a third number of segments of the first number of segments; and
combining the smallest maximum with the minimum, and wherein the sound signal is processed by the subtracting the combined smallest maximum and minimum from the sound signal.
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Specification