AUDIO SIGNAL PROCESSING DEVICE, SIGNAL RECOVERING DEVICE, AUDIO SIGNAL PROCESSING METHOD AND SIGNAL RECOVERING METHOD

• US 20070016407A1
• Filed: 09/22/2006
• Published: 01/18/2007
• Est. Priority Date: 01/21/2002
• Status: Active Grant

• Current Assignee: Rakuten Group, Inc.
• Original Assignee: Kenwood Corporation (JVC Kenwood Corporation)
• Inventors: Sato, Yasushi
• Granted Patent: US 7,606,711 B2
• Time in Patent Office: Days
• US Class Current: 704/205
• CPC Class Codes: G10L 19/018 Audio watermarking, i.e. embedding inaudible data in the audio signal
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 25/90 Pitch determination of speech signals
• CPC Class Codes: H04S 1/007 in which the audio signals are in digital form data reduction aspects thereof based on psychoacoustics G10L19/02

Abstract

The pitch extracting part generates a pitch waveform signal in a manner making the time interval of the pitch of the input audio sound data to be the same. After the number of samples in each region is made to be the same by the re-sampling part, the pitch waveform signal is changed into a subband data that express a time-varying-strength of a basic frequency composition and a higher harmonic composition by the subband analyzing part. The subband data are superimposed by a modulation wave composition that expresses attaching data of an attaching object by the data attaching part and is regarded as a bit stream to output through a nonlinear quantizing. A portion expressing the higher harmonic composition that is made corresponding to the audio sound expressed by this audio sound data in the subband data are deleted by the encoding part.

Claims

1. An audio signal processing device, comprising:

a subband extracting means for generating a subband signal that expresses a time-varying-strength of a basic frequency composition and a higher harmonic composition of an audio signal of a processing object that expresses a waveform of an audio sound; and

a deleting means for generating a deleted subband signal that expresses a result of deleting a portion expressing a time-varying higher harmonic composition of a deleting object that is made corresponding to the audio sound in the subband band signal generated by the subband extracting means.

2. The device according to claim 1, wherein a corresponding relationship between each audio sound made by a specific speaker and the higher harmonic composition of the deleting object made correspond to each the audio sound is particularly possessed by the speaker.

3. The device according to claim 2, wherein the deleting means rewritably stores a table that expresses the corresponding relationship and generates the deleted subband signal according to the corresponding relationship that is expressed by the table stored by itself.

4. The device according to claim 1, wherein the deleting means generates the deleted subband signal that expresses the result of deleting the portion expressing the time-varying higher harmonic composition of the deleting object that is made corresponding to the audio sound in a linearly quantized one that is a linear quantization of the filtered subband signal.

5. The device according to claim 4, wherein the deleting means obtains the deleted subband signal and determines a quantization characteristic of the nonlinear quantizing according to a data amount of the obtained deleted subband signal and practices the nonlinear quantizing according to the determined quantization characteristic.

6. The device according to claim 1, further comprising:

a removing means for specifying a portion that expresses a fricative in the audio signal of the processing object and removing the specified portion out of an object that deletes a portion expressing a time-varying higher harmonic composition of the deleting object.

7. The device according to claim 1, further comprising:

a pitch waveform signal generating means for obtaining the audio signal of the processing object and processing the audio signal into a pitch waveform signal by making the time interval of the region correspond to the unit pitch of the audio signal,

wherein the subband extracting means generates the subband signal according to the pitch waveform signal.

8. The device according to claim 7, wherein the subband extracting means comprising:

a variable filter for extracting the basic frequency composition of the audio sound of the processing object by making a frequency characteristic change according to a control and filtering the audio signal of the processing object;

a filter characteristic determining means for specifying the basic frequency of the audio sound according to the basic frequency composition that has been extracted from the variable filter and controlling the variable filter with a frequency characteristic that masks a composition out of a portion nearby the specified basic frequency;

a pitch extracting means for dividing the audio signal of the processing object into a region constructed by the audio signal in the unit pitch according to the basic frequency composition of the audio signal; and

a pitch length fixing part for generating a pitch waveform signal with each time interval within the region is substantial the same by sampling each the region of the audio signal of the processing object with a substantially same number of samples.

9. The audio signal processing method, comprising:

generating a subband signal that expresses a time-varying-strength of a basic frequency composition and a higher harmonic composition of an audio signal of a processing object that expresses a waveform of an audio sound; and

generating a deleted subband signal that expresses a result of deleting a portion expressing a time-varying higher harmonic composition of a deleting object that is made corresponding to the audio sound in the generated subband signal.