Speech signal compression device, speech signal compression method, and program

• US 20060167690A1
• Filed: 03/26/2004
• Published: 07/27/2006
• Est. Priority Date: 03/28/2003
• Status: Active Grant

• Current Assignee: Rakuten Group, Inc.
• Original Assignee: Kabushiki Kaisha Kenwood
• Inventors: Sato, Yasushi
• Granted Patent: US 7,653,540 B2
• Time in Patent Office: Days
• US Class Current: 704/249
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: G10L 25/90 Pitch determination of speech signals

Abstract

There is provided a speech signal noise elimination device and the like for eliminating noise mixed in speech with certainty. A pitch analysis section 2 determines the modified moving average of frequencies of pitch components of speech indicated by an original speech signal acquired by a speech input section 1. A variable filter 3 extracts the pitch components by removing from an original speech signal components other than components at and around the modified moving average determined by the pitch analysis section 2. An absolute value detection section 4 determines an absolute value of the pitch components, and a lowpass filter 5 filters a signal indicating the obtained absolute value to generate a gain adjustment signal. Then, the original speech signal, for which timing is adjusted by a delay section 6, is amplified or attenuated by a gain adjustment section 7 by gain determined by the value of the gain adjustment signal and outputted.

Claims

1. A speech signal compression device comprising:

division-according-to-phoneme means for acquiring a speech signal indicating a speech waveform to be compressed, and dividing the speech signal into portions indicating waveforms of individual phonemes;

a filter for filtering the divided speech signal to extract a pitch signal;

phase adjustment means for separating the speech signal into sections based on the pitch signal extracted by the filter and adjusting, for each of the sections, the phase based on correlation relation with the pitch signal;

sampling means for determining, for each of the sections for which the phase has been adjusted by the phase adjustment means, the sampling length based on the phase and generating a sampling signal by performing sampling in accordance with the sampling length;

speech signal processing means for processing the sampling signal to be a pitch waveform signal based on the result of the adjustments by the phase adjustment means and the value of the sampling length;

sub-band data generation means for generating sub-band data indicating change with time of spectral distribution of each of the phonemes based on the pitch waveform signal; and

compression-according-to-phoneme means for performing data compression of the sub-band data in accordance with a predetermined condition specified for a phoneme indicated by the sub-band data.

2. The speech signal compression device according to claim 1, wherein

the compression-according-to-phoneme means is configured by:

means for rewritably storing a table which specifies a condition of data compression to be performed for sub-band data indicating each phoneme; and

means for performing data compression of sub-band data indicating each phoneme in accordance with a condition specified by the table.

3. The speech signal compression device according to claim 1 or 2, wherein

the compression-according-to-phoneme means performs data compression of sub-band data indicating each phoneme by nonlinearly quantizing the data so that the compression rate to satisfy a condition specified for the phoneme is reached.

4. The speech signal compression device according to claim 1 or 2, wherein

priority is specified for each spectral component of sub-band data;

and

the compression-according-to-phoneme means performs data compression of sub-band data by quantizing each of spectral components of the sub-band data in a manner that a spectral component with a higher priority is quantized with a higher resolution.

5. The speech signal compression device according to claim 1 or 2, wherein

the compression-according-to-phoneme means performs data compression of sub-band data by changing the sub-band data so that spectral distribution after deletion of a predetermined spectral component is shown.

6. A speech signal compression device, comprising:

speech signal processing means for acquiring a speech signal indicating a waveform of speech, and processing the speech signal to be a pitch waveform signal by substantially equalizing phases of multiple sections obtained by separating the speech signal, each of the multiple sections corresponding to a unit pitch of the speech;

sub-band data generation means for generating sub-band data indicating change with time of spectral distribution of each of the phonemes based on the pitch waveform signal; and

compression-according-to-phoneme means for performing data compression of each of portions indicating individual phonemes of the sub-band data in accordance with a predetermined condition specified for a phoneme indicated by the portion.

7. A speech signal compression device, comprising:

means for acquiring a signal indicating a speech waveform or change with time of spectral distribution of speech; and

means for performing data compression of each of portions indicating individual phonemes of the acquired signal in accordance with a predetermined compression rate specified according to the feature of a phoneme indicated by the portion.

8. A speech signal compression method, wherein

a signal indicating a speech waveform or change with time of spectral distribution of speech is acquired;

and

data compression is performed for each of portions indicating individual phonemes of the acquired signal in accordance with a predetermined compression rate specified according to the feature of a phoneme indicated by the portion.

9. A program causing a computer function as:

means for acquiring a signal indicating a speech waveform or change with time of spectral distribution of speech; and

means for performing data compression of each of portions indicating individual phonemes of the acquired signal in accordance with a predetermined compression rate specified according to the feature of a phoneme indicated by the portion.