Voice communication system encoding and decoding voice and non-voice information

A non-transitory computer-readable storage medium having a voice encoding program stored thereon, said voice encoding program being executed by a computer to control the computer to function as a voice coding apparatus encoding an input signal to generate a code and embedding additional information into the generated code, said voice encoding program causing the computer to function as:

• a voice detector making a decision as to whether the input signal is in a voice section or in a background noise section and generating a switching signal associated with a result of the decision;
• a voice code generator generating a voice code based on the input signal in the voice section;
• a noise code generator operative in response to the input signal in the background noise section for extracting a noise feature parameter, which a voice decoder at a destination of the input signal uses to reconstruct the input signal in the background noise section, to encode the extracted parameter to thereby generate a noise code;
• a selector operative in response to the switching signal for switching the input signal between said voice code generator and said nose code generator;
• an embedding position controller determining an embedding position of the additional information according to the noise feature parameter extracted to control the embedding position;
• and
• an information embedder embedding the additional information at the embedding position of the voice code or noise code determined by said embedding position controller,
• the embedding position being set in advance according to a correspondence relationship with the noise feature parameter.

A voice decoding apparatus extracting additional information from a received code having the additional information embedded therein for restoring a signal intended by a voice coding apparatus at a transmission source, said decoding apparatus comprising:

• a voice/noise section discriminator making a decision as to whether the received code is in a voice section or in a background noise section and generating a switching signal associated with a result of the decision;
• a voice decoder decoding a voice signal based on the received code in the voice section;
• a noise decoder obtaining a noise feature parameter based on the received code in the background noise section and generating a noise signal approximating a background noise characteristic of the voice coding apparatus;
• a selector operative in response to the switching signal for switching the received code between said voice decoder and said noise decoder;
• a signal reproducer outputting the voice signal and the noise signal obtained by said voice decoder and said noise decoder;
• a memory storing in advance a correspondence relationship between the noise feature parameter and an embedding position where the additional information is to be embedded;
• an embedding position collator supplying the obtained noise feature parameter as collation information to said memory and collating the embedding position of the additional information associated with the collation information;
• an additional-information extractor extracting a bit value lying at the embedding position collated with respect to the received code;
• and
• an additional-information reproducer forming the extracted bit values into a stream of bits to output the additional information.

A non-transitory computer-readable storage medium having a voice decoding program stored thereon, said voice decoding program being executed by a computer to control the computer to function as a voice decoding apparatus extracting additional information from a received code having the additional information embedded therein and restoring a signal intended by a voice coding apparatus at a transmission source, said voice decoding program causing the computer to function as:

• a voice/noise section discriminator making a decision as to whether the received code is in a voice section or in a background noise section and generating a switching signal associated with a result of the decision;
• a voice decoder decoding a voice signal based on the received code in the voice section;
• a noise decoder obtaining a noise feature parameter based on the received code in the background noise section and generating a noise signal approximating a background noise characteristic of the voice coding apparatus;
• a selector operative in response to the switching signal for switching the received code between said voice decoder and said noise decoder;
• a signal reproducer outputting the voice signal and the noise signal obtained by said voice decoder and said noise decoder;
• a memory storing in advance a correspondence relationship between the noise feature parameter and an embedding position where additional information is to be embedded;
• an embedding position collator supplying the obtained noise feature parameter as collation information to said memory and collating the embedding position of the additional information associated with the collation information;
• an additional-information extractor extracting a bit value lying at the embedding position collated with respect to the received code;
• and
• an additional-information reproducer forming the extracted bit values into a stream of bits to output the additional information.

A voice communication system comprising a voice coding apparatus encoding an input signal to generate a code and embedding additional information in the generated code, and a voice decoding apparatus extracting the additional information from a received code having the additional information embedded therein for restoring a signal intended by said voice coding apparatus at a transmission source, wherein

• said voice coding apparatus comprises:
• a voice detector making a decision as to whether the input signal is in a voice section or in a background noise section and generating a first switching signal associated with a result of the decision;
• a voice code generator generating a voice code based on the input signal in the voice section;
• a noise code generator operative in response to the input signal in the background noise section for extracting a noise feature parameter, which a voice decoder at a destination of the input signal uses to reconstruct the input signal in the background noise section, to encode the extracted parameter to thereby generate a noise code;
• a first selector operative in response to the first switching signal for switching the input signal between said voice code generator and said noise code generator;
• an embedding position controller determining the embedding position of the additional information according to the noise feature parameter extracted to control the embedding position;
• and
• an information embedder embedding the additional information at the embedding position of the voice code or noise code determined by said embedding position controller,
• the embedding position being set in advance according to a correspondence relationship with the noise feature parameter,
• said voice decoding apparatus comprising:
• a voice/noise section discriminator making a decision as to whether the received code is in a voice section or in a background noise section and generating a second switching signal associated with a result of the decision;
• a voice decoder decoding a voce signal based on the received code in the voice section;
• a noise decoder obtaining the noise feature parameter based on the received code in the background noise section and generating a noise signal approximating a background noise characteristic of said voice coding apparatus;
• a second selector operative in response to the second switching signal for switching the received code between said voice decoder and said noise decoder;
• a signal reproducer outputting the voice signal and the noise signal obtained by said voice decoder and said noise decoder;
• a memory storing in advance a correspondence relationship between the noise feature parameter and an embedding position where additional information is to be embedded;
• an embedding position collator supplying the obtained noise feature parameter as collation information to said memory and collating the embedding position of the additional information associated with the collation information;
• an additional-information extractor extracting a bit value lying at the embedding position collated with respect to the received code;
• and
• an additional-information reproducer forming the extracted bit values into a stream of bits to output the additional information.