Speech section detection apparatus
First Claim
1. A speech section detection apparatus comprising:
- preprocessing means for removing noise contained in a speech signal;
signal-to-noise ratio improving means for improving the signal-to-noise ratio of said speech signal from which noise has been removed by said preprocessing means; and
speech section extracting signal generating means for generating a speech section extracting signal based on said speech signal whose signal-to-noise ratio has been improved by said signal-to-noise improving means.
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Abstract
A speech section detection apparatus capable of reliably detecting a speech section even in the case of a speech signal with low signal-to-noise ratio. The speech signal collected by a microphone and amplified by a line amplifier is converted by an A/D converter into a digital value, which is then stored in a memory. After removing noise from the digitized speech signal, the signal-to-noise ratio is improved by taking short-time auto-correlation and, when the signal level has continued to stay above a threshold value for a predetermined period, it is determined that a speech section has been detected. Further, a prescribed period before and after the thus determined speech section is also forcefully set as a target for extraction so that the beginning and end of the speech section can be reliably detected. Furthermore, to prevent noise from accumulating and causing the threshold value to increase excessively, the threshold value is updated as appropriate by multiplying a moving average taken over a prescribed period in a non-speech section by a predetermined factor, and by setting the resulting product as the threshold value.
17 Citations
10 Claims
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1. A speech section detection apparatus comprising:
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preprocessing means for removing noise contained in a speech signal;
signal-to-noise ratio improving means for improving the signal-to-noise ratio of said speech signal from which noise has been removed by said preprocessing means; and
speech section extracting signal generating means for generating a speech section extracting signal based on said speech signal whose signal-to-noise ratio has been improved by said signal-to-noise improving means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification