US20050232436A1 - Communication system using short range radio communication headset - Google Patents

Abstract

In a short range radio communication headset, signals transmitted by the short range radio communications are received while direct sounds propagated from an external are detected. Then, a digital signal adaptation processing using either received signals or the direct sounds as reference signals are applied, and a ratio between the received signals and the direct sounds is controlled by correlating the reference signals and another one of the received signals and the direct sounds that are not used as the reference signals and extracting necessary components.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a division of and claims the benefit of priority under 35 USC §120 from U.S. Ser. No. 10/325,934, filed Dec. 23, 2002, and claims the benefit of priority under 35 USC §119 from the prior Japanese Patent Application No. 2000-275030, filed on Sep. 11, 2000; the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The present invention relates to an acoustic processing technique for a short range radio communication headset, and more particularly to a headset communication system that realizes smoothing of communications by selectively adjusting and controlling necessary speeches from a plurality of types of speeches.
• 2. Description of the Related Art
• A short range wireless communication system called Bluetooth has developed so that it becomes possible to connect and control devices such as PC, printer, portable telephone, digital camera, etc., within rooms or offices, without using any cords.
• In this trend, in order to urge the application of the system to the mobile environment, there is a proposition to use a headset with a speech input function. The short range radio communication system centered around the headset with a speech input function is intended for communications and device controlling within about 10 m, which is a distance range visible by eyes. For this reason, in addition to the speeches transmitted/received through the radio communications, speeches directly uttered to a correspondent, speeches of a nearby third person, and noises will also reach to the user's ears. Consequently, there is a need for a technique to eliminate the unnecessary sounds according to the situation, such that only the necessary sounds can be extracted and outputted to the user's ears.
• As the conventional speech processing techniques, the active noise control and the echo canceller technique for the long distance telephone lines are known. The active noise control tries to cancel all the arriving sounds without selecting the sound types. The echo canceller technique for the long distance telephone lines tries to cancel echoes. These techniques are not something that was developed for the short range radio communication headset so that it is difficult to apply them in their original forms.
• FIG. 11 shows a feedback type active noise canceller used by a headset for acoustic use. Amicrophone101 is mounted on a headphone mount, and the microphone signals are multiplied by some filter coefficient by thecontroller105 and sent to aheadphone speaker103, and made to interfere with the external sounds to cancel them out. At this point, the filter coefficient is constantly adjusted such that the sounds picked up by the microphone becomes minimum. This is the feedback control for controlling output by feeding back the control target signals. The feedback type has a limit to the amount of noise reduction, but a configuration is relatively simple so that it is often used as the active noise canceller of a headset for acoustic use.
• FIG. 12 shows an exemplary general method used for the noise removal. In the example ofFIG. 12, the human voice alone is extracted from signals in which the human voice and the sounds coming from theheadphone speaker113 as a noise source are mixed.
• Examples shown inFIG. 11 andFIG. 12 are not something that was developed for the short range radio communication system, and there has been no proposition conventionally of a method for comparing the sounds transmitted by the radio communications and the external sounds that are directly picked up, and reinforcing or reducing either one of them selectively according to the situation.
BRIEF SUMMARY OF THE INVENTION
• It is therefore an object of the present invention to provide a headset capable of making speech communications and speech commands smooth by selectively changing a ratio of the external direct sounds and the sounds transmitted by the radio communications, in every possible situation under which the short range radio communication headset is expected to be utilized, and a communication system using such a headset.
• The short range headset system of the present invention will be useful in communications with respect to mass audience such as those of a conference, a lecture, a factory tour, a museum tour, etc., random communications among plural persons, one-to-one dialogue style communications, recording of contents of these communications, dictation by a single person, and speech command controlling of a device equipped with a short range wireless communication function such as Bluetooth, for example.
• According to one aspect of the present invention there is provided a short range radio communication headset, comprising: a transmitter configured to transmit or receive signals by short range radio communications; an external sound detection microphone configured to detect direct sounds propagated from an external; a speech processing unit configured to receive inputs of received signals received by the transceiver and the direct sounds detected by the external sound detection microphone, and selectively control a ratio between the received signals and the direct sounds; and a speaker configured to output speeches with the ratio controlled by the speech processing unit.
• According to another aspect of the present invention there is provided a short range radio communication headset system, comprising: a first headset for short range radio communications; a second headset for short range radio communications which transmits speeches to the first headset; and a speech processing device configured to apply a speech processing to the speeches transmitted by the second headset and supply processed signals to the first headset; wherein the first headset has a receiver, an external sound detection microphone for detecting direct sounds from an external, and a transmitter for transmitting the direct sounds to the speech processing device at a first frequency; the second headset has a transmitter for transmitting the speeches to the speech processing device at a second frequency; and the speech processing device receives the direct sounds from the first headset and the speeches from the second headset, selectively adjusts a ratio of the direct sounds and the speeches and transmits adjusted signals to the first headset at a third frequency.
• According to another aspect of the present invention there is provided a short range radio communication headset, comprising: a speaker's microphone configured to detect a speech command of a user; an external sound detection microphone configured to detect external sounds of a surrounding; a speech processing unit configured to receive inputs of the speech command and the external sounds, correlate the external sounds with the speech command, and extract only components correlated with the speech command; and a transmitter configured to transmit an output of the speech processing unit to a remote device by a short range radio communication.
• According to another aspect of the present invention there is provided a short range radio communication headset, comprising: a transmitter capable of radio transmission with respect to surrounding devices; a speaker's microphone configured to detect speeches of a user; a speech recognition unit configured to recognize the speeches detected by the speaker's microphone; and a recognition result transmission unit configured to supply a recognition result obtained by the speech recognition unit to the transmitter, such that the recognition result is transmitted from the transmitter.
• According to another aspect of the present invention there is provided an acoustic processing method for short range radio communications, comprising: receiving signals transmitted by the short range radio communications; detecting direct sounds propagated from an external as sound waves; applying a digital signal adaptation processing using either received signals or the direct sounds as reference signals; controlling a ratio between the received signals and the direct sounds by correlating the reference signals and another one of the received signals and the direct sounds that are not used as the reference signals and extracting necessary components; and outputting signals with the ratio controlled by the controlling step as speeches.
• According to another aspect of the present invention there is provided an acoustic processing method for a short range radio communication headset system, comprising: receiving direct sounds from an external detected by a first headset as first received signals through short range radio communications; receiving speeches transmitted by a second headset to the first headset as second received signals through short range radio communications; applying an adaptation processing using either the first received signals or the second received signals as reference signals; controlling a ratio of the first received signals and the second received signals by correlating the reference signals and another one of the first received signals and the second received signals that are not used as the reference signals and extracting necessary components; and transmitting signals with the ratio controlled by the controlling step to the first headset through the short range radio communications.
• Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a diagram showing an overview of a short range radio communication headset according to the first embodiment of the present invention.
• FIG. 2 is a diagram showing a basic flow of data in the headset ofFIG. 1.
• FIGS. 3A and 3B are diagrams showing the speech processing of the headset ofFIG. 1 in the case of using a speech received through a radio communication as a reference signal.
• FIG. 4 is a diagram showing the speech processing of a headset system using a plurality of the headset ofFIG. 1 in the case of using a speech received through a radio communication as a reference signal.
• FIGS. 5A and 5B are diagrams showing the speech processing of the headset ofFIG. 1 in the case of using a direct sound from an external as a reference signal.
• FIG. 6 is a diagram showing the speech processing of a headset system using a plurality of the headset ofFIG. 1 in the case of using a direct sound from an external as a reference signal.
• FIG. 7 is a diagram showing an overview of a short range radio communication headset system according to the second embodiment of the present invention.
• FIG. 8 is a diagram showing an overview of a short range radio communication headset according to one modified embodiment of the present invention.
• FIG. 9 is a block diagram showing a speech recognition processing system to be used in association with a headset according to another modified embodiment of the present invention.
• FIG. 10 is a block diagram showing an internal configuration of a speech recognition unit shown inFIG. 9.
• FIG. 11 is a diagram showing an overview of a conventionally known general headset for acoustic use.
• FIG. 12 is a block diagram showing a conventionally known general acoustic processing system for noise removal.
DETAILED DESCRIPTION OF THE INVENTION
• Referring now toFIG. 1 toFIG. 6, the first embodiment of the present invention will be described in detail.
• FIG. 1 shows a short range radio communication headset (hereafter referred simply as “headset”) according to the first embodiment of the present invention. Aheadset10 with a short range radio communication function has an externalsound detection microphone13 for picking up direct sounds propagating from the external as sound waves, atransceiver11 for transmitting or receiving speeches through radio communications, aspeech processing unit15 for receiving inputs of the direct sounds picked up by the externalsound detection microphone13 and the speeches received by thetransceiver11 and controlling a ratio of the direct sounds and received signals, and aheadphone speaker17 for outputting speeches with its ratio controlled by thespeech processing unit15.
• Theheadset10 may additionally have a speaker'smicrophone19 for detecting a voice of a wearer (user) of theheadset10. The speaker'smicrophone19 is used in the case where the speech command is to be issued to a surrounding device through thetransceiver11 or in the case where the radio communication is to be carried out with a second headset (not shown).
• Theheadset10 also has amode changing switch16 connected to thespeech processing unit15. The user can determine to make the direct sounds from the external dominant or the speeches received through the radio communication dominant in the processing of thespeech processing unit15, by operating themode changing switch16 according to the situation. Such amode changing switch16 may be provided in a form of a button that is connected to thespeech processing unit15 through a cord such that it can be placed near at hand of the user for easy operation.
• FIG. 2 shows a flow of data in theheadset10 shown inFIG. 1. The direct sounds detected by the externalsound detection microphone13 and the speeches received by thetransceiver11 of the headset are both inputted into thespeech processing unit15. Thespeech processing unit15 changes a ratio of the direct sounds and the received speeches, and outputs them to theheadphone speaker17. The exemplary ways of changing the ratio may include the following.
• (1) When it is desired to hear the speeches received through the radio communication preferentially, the direct sounds from the external are selectively removed. For example, only the components correlated with the speeches received through the radio communication are left and all the other non-correlated portions are deleted. In this way, the speeches of the radio communication are reinforced such that it becomes easier to hear the communication content.
• (2) When it is desired to hear the direct sounds preferentially, the speeches received through the radio communication are selectively removed. For example, all portions not correlated with the direct sounds are deleted and only the correlated components are extracted. In this way, even in a state of wearing theheadset10, it becomes easier to hear the direct sounds from the external as they are reinforced. In particular, in the case of carrying out the dialogue type radio communication through theheadset10 at relatively close positions, there can be cases where the direct sounds and the received speeches of the same contents are mixed up such that it becomes rather hard to listen, but in such cases it becomes possible hear the direct sounds dominantly in this way.
• (3) When it is desired to hear only the speeches received through the radio communication, all the direct sounds from the external are shut off. This control is carried out when it becomes difficult to hear the received speeches as the direct sounds contain many noises.
• (4) The volume of the speeches received through the radio communication is changed according to a positional relation between the source and theheadset10 at the receiving side, using a position information of the source. In this case, transmission/reception of the position information becomes necessary in addition to transmission/reception of the speech data, through the radio communication.
• As a way of realizing the above described correlation processing, it is possible to use an adaptive filter for executing the adaptation processing and the correlation calculation, for example.
• FIGS. 3A and 3B show an exemplary operation of thespeech processing unit15 ofFIG. 1, that is, the operation for controlling a ratio of the direct sounds from the external and the speeches received through the radio communication.
• FIG. 3A shows the case where the speech received by thetransceiver11 through the radio communication is a single speech and the direct sounds from the external contain plural mixed sounds, and it is desired to hear the direct sounds. Note that the speaker'smicrophone19 and themode changing switch16 are omitted in the figure for the sake of simplicity.
• Thespeech processing unit15 mainly comprises a DSPadaptation processing unit24 for applying the DSP adaptation processing using signals received through the radio communication as reference signals, and acorrelation processing unit25 for correlating the DSP adaptation processed received signals with the direct sounds from the external that are picked up by the externalsound detection microphone13. Thecorrelation processing unit25 obtains the correlation in the requested mode and outputs only the necessary components. An adaptive filter is formed by the DSPadaptation processing unit24 and thecorrelation processing unit25.
• As the speech processing operation, the user selects a desired mode (a direct sound mode, for example) by operating themode changing switch16 first. Thespeech processing unit15 carries out the DSP adaptation processing using the single sound of the speech received through the radio communication as the reference signal, and supplies the processed speech to thecorrelation processing unit25. On the other hand, the direct sounds picked up by the externalsound detection microphone13 are A/D converted and supplied to thecorrelation processing unit25. Thecorrelation processing unit25 removes components correlated to the reference signal obtained from the radio communication among the direct sounds according to the selected mode and outputs only the non-correlated components. In this way, the portions correlated with the speeches of the radio communication are removed and the direct sounds from the external that are made clearer will be sent to theheadphone speaker17.
• Such a mode will be selected in the case where there is an announcement during a conversation through the headset at a party site, for example.
• FIG. 3B shows the case where the speech received by thetransceiver11 through the radio communication is a single speech and the direct sounds from the external contain plural mixed sounds, and it is desired to hear the speech received by thetransceiver11.
• The user selects a desired mode (a communication mode) by operating themode changing switch16 first. Thespeech processing unit15 carries out the DSP adaptation processing using the single sound of the speech received byth transceiver11 as the reference signal, and supplies the processed speech to thecorrelation processing unit25. On the other hand, the direct sounds picked up by the externalsound detection microphone13 are A/D converted and supplied to thecorrelation processing unit25. Thecorrelation processing unit25 removes components not correlated to the reference signal obtained from the radio communication among the direct sounds and outputs only the correlated components. In this way, the speech received through the radio communication is outputted in the reinforced state from theheadphone speaker17.
• FIG. 4 shows the case where a first user wearing afirst headset10 and a second user wearing asecond headset20 carry out dialogue.
• To the first user wearing thefirst headset10, the speech of the second user received by thetransceiver11 through the radio communication and the direct sounds propagated through the air as sound waves reach. In the direct sounds picked up by the externalsound detection microphone13, the speech of the second user is mixed with a plurality of other speeches, which sounds like noises. The first user selects the communication mode in order to weaken the direct sounds of the external and hear the speech of the second user transmitted by the radio communication more clearly. Here, it is assumed that the transfer function of the transceiver is1 and the the externalsound detection microphone13 picks up the direct sounds multiplied by an acoustic spatial transfer function G, for the sake of simplicity.
• In the headset system ofFIG. 4, in response to the selection of the communication mode by the first user, the received speech is set as the reference signal. At this point, what is corresponding to the acoustic spatial transfer function G of the space is set to the DSPadaptation processing unit24 of thespeech processing unit15. Thecorrelation processing unit25 obtains the correlation between the reference signal processed by the DSP processing according to the acoustic spatial transfer function G and the direct sounds processed by the digital conversion processing, and outputs only the components correlated with the reference signal to theheadphone speaker17.
• The output of thecorrelation processing unit25 is also supplied to the DSPadaptation processing unit24. The DSPadaptation processing unit24 processes received signals of the radio communication that are inputted this time such that an error becomes smaller than the processing result of the previous time.
• By such an operation of the adaptive filter, the effect similar to the application of the automatic delay processing is produced in the received signals of the radio communication which have the propagation speed faster than that of the sound waves.
• In this way, it becomes possible to remove only the speech of the second user from the direct sounds, by synchronously correlating the reference signal of the radio communication and the direct sounds picked up by the externalsound detection microphone13.
• FIGS. 5A and 5B show the case that is opposite to the case shown inFIGS. 3A and 3B, that is, the case where the direct sound picked up by the externalsound detection microphone13 is a single sound and the speeches received by thetransceiver11 through the radio communication contain plural mixed sounds.
• FIG. 5A shows the case where it is desired to hear the speeches transmitted through the radio communication rather than the single direct sound from the external. The user selects a desired mode (a communication mode) by operating themode changing switch16 first. Thespeech processing unit15 carries out the processing according to the mode selected by the user. The single direct sound picked up by the externalsound detection microphone13 is A/D converted, applied with the DSP adaptation processing as the reference signal, and supplied to thecorrelation processing unit25. On the other hand, the speeches received byth transceiver11 through the radio communication are also sent to thecorrelation processing unit25. Thecorrelation processing unit25 removes components correlated with the external sound picked up by the externalsound detection microphone13 among the speeches received by thetransmitter11, and outputs only the non-correlated components to theheadphone speaker17. In this way, the speeches received through the radio communication can be heard clearly from theheadphone speaker17, without being obscured by the direct sound.
• FIG. 5B shows the case where it is desired to hear the single direct sound picked up by the externalsound detection microphone13 clearly rather than the speeches received through the radio communication. The user selects a desired mode (a direct sound mode) by operating themode changing switch16 first. Thespeech processing unit15 carries out the DSP adaptation processing according to the mode selected by the user, by using the direct sound as the reference signal. The direct sound processed by the DSP adaptation processing is supplied to thecorrelation processing unit25. On the other hand, the speeches received through the radio communication are also sent to thecorrelation processing unit25. Thecorrelation processing unit25 removes components not correlated with the external sound among the speeches received through the radio communication, and outputs only the correlated components to theheadphone speaker17. In this way, the direct sound can be heard clearly in the reinforced state by the ear of the user.
• FIG. 6 shows the case where a first user wearing afirst headset10 and a second user wearing asecond headset20 carry out dialogue, in the state of using the direct sound as the reference signal as inFIGS. 5A and 5B.
• If it is attempted to use the direct sound as the reference signal in the system configuration shown inFIG. 4, the system should operates such that what is corresponding to the inverse of the acoustic spatial transfer function G of the air (1/G) should be set to the DSPadaptation processing unit24. However, 1/G is of a non-minimum phase type which has a form in which the coefficient appears in a negative time region of the impulse response, which is unrealizable.
• For this reason, as shown inFIG. 6, adelay circuit26 is inserted between the signals received through the radio communication and thecorrelation processing unit25. Namely, thespeech processing unit15 comprises thedelay circuit26 for delaying signals transmitted through the radio communication, and the adaptive filter (24,25) for extracting necessary components by correlating the reference signal and the delayed received signals, using the direct sound from the external as the reference signal.
• As described above, the propagation speed of the signals received through the radio communication is faster than that of the sound waves (direct sounds) in the air. By operating the system while giving the sufficient delay to the signals propagated through the radio communication, the impulse response set to the adaptive filter is displaced as much as the inserted delay so that the appearance of the coefficient in the negative time region can be eliminated,
• With this configuration, even in the case where the direct sound from the external is used as the reference signal, it becomes possible to adjust the ratio of the signals received through the radio communication and the direct sound appropriately, so that it is possible to realize the speech control according to the situation.
• According to the headset system of the first embodiment, it becomes possible to adjust and control the radio of the signals received from the radio communication and the direct sounds from the external, based on the selection made by the user according to the situation.
• Also, according to the headset system of the first embodiment, it becomes possible to apply appropriate delay processing in either case of using the received signals of the radio communication or the direct sounds from the external as the reference signals, so that it is possible to correlate both of them effectively.
• The headset system of the first embodiment is suitable for the applications to the conference or party site, the conversation in the crowd, and the guidance of a tour through the factory or the like.
• Referring now toFIG. 7, the second embodiment of the present invention will be described in detail.
• FIG. 7 shows a headset system according to the second embodiment of the present invention. In the second embodiment, thespeech processing unit15 that was provided inside the headset in the first embodiment is provided as an independent external device. Consequently, the control of the ratio between the speeches of the speaker transmitted through the radio communication and the direct sounds picked up from the external is carried out outside of the headset.
• As shown inFIG. 7, the headset system of the second embodiment contains afirst headset40, asecond headset50, and an externalspeech processing device30. Thespeech processing device30 may be incorporated into a server of a communication center within a communication possible range, or may be incorporated into a mobile terminal (PC, portable telephone, PDA, etc.), for example.
• Thefirst headset40 has an externalsound detection microphone13, atransmitter44 for A/D converting the direct sounds picked up by the externalsound detection microphone13 and transmitting them to thespeech processing device30, and atransceiver unit11. Thetransmitter44 transmits the direct sounds of the external that after the digital conversion is applied to thespeech processing device30 at a first frequency.
• Thesecond headset50 has a speaker'smicrophone29 and atransceiver21. Thetransceiver21 transmits the communication content of the wearer of thesecond headset50 to thespeech processing device30 at a second frequency.
• Thespeech processing device30 has a transmitting sidesound receiving unit32a for receiving speech transmitted from thesecond headset50, and a receiving sidesound receiving unit32bfor receiving direct sounds transmitted from thetransmitter44 of thefirst headset40. A DSPadaptation processing unit34 applies the DSP adaptation processing using the received signal of either one of the transmitting sidesound receiving unit32aor the receiving sidesound receiving unit32bas the reference signal, and supplies the signal applied with the DSP adaptation processing to acorrelation processing unit35. Thecorrelation processing unit35 obtains a correlation between the DSP adaptation processing applied reference signal and the other received signal, and outputs only desired components. Atransmission unit36 transmits the output of thecorrelation processing unit35 to thefirst headset40 at a third frequency.
• The receiving function of thetransmitter11 of thefirst headset40 is configured such that it does not receive the transmission frequency of thesecond headset50 and it receives the radio signals from thespeech processing device30.
• In the example ofFIG. 7, only the necessary functions are shown by assuming that thefirst headset40 is the receiving side and thesecond headset50 is the transmitting side for the sake of simplicity, but it is possible for each headset to have the same configuration. In that case, both of thefirst headset40 and thesecond headset50 have the externalsound detection microphone13, thetransmitter44, and the speaker'smicrophone17.
• In the example shown inFIG. 7, the speech transmitted from thesecond headset50 is used as the operation of thespeech processing device30. Thespeech processing device30 obtains a correlation between the direct sounds picked up by the externalsound detection microphone13 of thefirst headset40 and the reference signal, and only the correlated components are extracted. As a result, the speech content transmitted from the speaking side are reinforced and transmitted from thetransmission unit36 to thefirst headset40. Of course, depending on the situation, it is also possible to output only the non-correlated components by removing the correlated components and transmit them to thefirst headset40 such that the direct sound can be heard clear.
• It is possible to provide the mode changing switch to eachheadset40 or50 such that the user can select which mode to switch by transmitting the output of the switch to thespeech processing device30.
• Alternatively, it is also possible to provide the mode changing switch to a server or PC side to which thespeech processing unit30 is to be implemented. In the case of the lectures, game shows, entertainments at the small theaters, etc., it is often proceeded according to a predetermined scenario. In such cases, it is possible to provide the mode changing switch to the server or PC of the communication center to which the speech processing device is to be incorporated, such that an operator carries out the mode switching operation manually. It is also possible to adopt a configuration in which the mode is changed automatically according to a program installed in advance.
• Furthermore, it is possible to use a configuration in which thespeech processing device30 is incorporated into the PDA or mobile terminal of the listener's side such that the user can selectively extracts the necessary speech components according to the situation.
• In the headset and the headset system using that headset according to the second embodiment, the speech processing function is provided outside of the headset so that the configuration of the headset itself becomes simple, and it is possible to reduce a size of the headset itself.
• Referring now toFIG. 8 toFIG. 10, the other modified embodiments of the present invention will be described in detail.
• In the first and second embodiments described above, the selective controlling of the speeches in the case where it is desired to hear the direct sound as well by the listener has been described, However, depending on the situation, there can be cases where it is desired to shut out the direct sounds entered from the external completely because only the speeches through the radio communication are important. In such cases, it is possible to make a switching to a mode in which the direct sounds are not inputted to the external sound detection microphone or the speech processing unit.
• Such a switching is realized by providing an opening/shuttingcontroller37 to aearphone18 of the headset as shown inFIG. 8. The opening/shuttingcontroller37 is a physical door provided outside the external sound detection microphone, for example, which can shut out the external sounds by closing it. Else, the opening/shuttingcontroller37 can be located at an input portion of the speech processing unit such that it can be realized as an electronically blocking circuit which is equivalent to the physical door with respect to'the sounds.
• In the first and second embodiments described above, the output from the adaptive filter of the speech processing unit is directly sent to the headphone speaker, but it is also possible to output the output of the adaptive filter by mixing it with the direct sounds or the speeches from the radio communication from the headphone speaker.
• Also, the above description of the present invention is directed to the case of using a headset for covering both ears, but it is also possible to use a headset for covering one ear. In particular, in the case of the second embodiment, the speech processing device is provided externally so that it is easier to make the headset in a smaller size and it is also possible to make a earplug type headset.
• Also, in the above description, the transceiver is provided on a band section of the headset, but it is also possible to provide it on the earphone along with the external sound detection microphone.
• Also, in the case of using a third headset in the above described headset system it is possible to transmit a relative positional information of the headset by radio communication separately from the speech signals. It is possible to calculate a distance between the transmitting side and the receiving side according to the positional information and change a cancelling target or controlling an amount of cancelling according to the calculated distance.
• It is also possible to attach a special ID signal to the speech to be transmitted/received through the radio communication, as a way of transmitting the speech in emergency. In this case, the speech processing unit also has a unit for detecting the emergency ID. When the emergency ID is detected, the correlation processing unit will not carry out the cancelling processing with respect to the signals received through the radio communication. In this way, it is possible to ensure the communication in the case of the emergency.
• In the first and second embodiments, the operation of the headset when there is a correspondent has been described, but the present invention is also applicable to the case where a single user wears the headset and issues the speech data or command to a surrounding device. For example, the present invention is suitable for the case of operating the air conditioner or the washing machine by the speech using the headset while the surrounding is noisy due to the TV or the music, the case of controlling on/off of a necessary device under the environment in which the operating sound of the other device is noisy, or the case of carrying out the dictation.
• In this case, as shown inFIG. 9, the speech command of the wearer (user) detected by the speaker'smicrophone29 of the headset is converted into the digital speech signal by an A/D converter41 first. Aspeech recognition unit43 recognizes the speech detected by the speaker'smicrophone29 and outputs the speech recognition result. The speech recognition result is then sent to a recognitionresult transmission unit45 having a short range radio communication function and communicated to the other devices from there.
• FIG. 10 shows an internal configuration of thespeech recognition unit43. The digital speech signal outputted from the A/D converter41 is inputted into anacoustic analysis unit51. Theacoustic analysis unit51 converts the input speech of a prescribed period of time into feature parameters. The output of theacoustic analysis unit51 is a time series of the feature parameters (feature parameter sequence). Theacoustic analysis unit51 outputs the obtained feature parameter sequence of the input speech to amodel matching unit53.
• On the other hand, a recognitionvocabulary memory unit55 stores pronunciation information for words necessary in producing a speech model of each word constituting the recognition vocabulary and a word ID to be outputted as the recognition result when each word is recognized.
• A recognition model production andstorage unit57 stores the speech model of each word and the word ID outputted from themodel matching unit53 as the recognition result when each word is recognized, in advance.
• Themodel matching unit53 calculates a similarity or a distance between each speech model of a recognition target word stored in the speech model production andmemory unit57 and the feature parameter sequence of the input speech, and outputs the word ID corresponding to the speech model with the maximum similarity (or the minimum distance) as the recognition result.
• The word ID outputted from themodel matching unit53 becomes the output of thespeech recognition unit43, and entered into the recognitionresult transmission unit45. The recognitionresult transmission unit45 transmits the word ID to the other devices by using a transmission function contained in the radio communication module.
• The A/D converted speech may be processed by the speech processing unit before it is entered into thespeech recognition unit43. In this case, the A/D converted speech of the user becomes the reference signal. The direct sounds picked up by the external sound detection microphone are correlated with this reference signal, and all the non-correlated components are removed. The output of the correlation processing unit is sent to thespeech recognition unit43 as a clearer signal in which the speech data of the user is reinforced.
• In such a headset, the switch operation or the keyboard operation is unnecessary, and the user's action is not obstructed, so that it becomes possible to send the speech data or the speech command to the other devices in real time. The user can carry out an accurate remote controlling in a hand-free state, so that the working efficiency can be improved.
• Also, by applying the speech processing to the speech uttered by the user, the clear speech data or speech command in which no noise is mixed can be transmitted so that it is possible to prevent the erroneous operation of the device.
• As described above, the user of the headset can selectively control the ratio of the speeches transmitted through the radio communication and the direct sounds from the external according to the situation of the surrounding.
• By extracting only the necessary speech information, it is possible to realize smooth speech communications that will not cause the mental stresses.
• Even when the surrounding is noisy, the speeches are outputted from the headphone speaker in a state of having the noises removed or reduced, so that the users wearing the headsets can carry out the conversation by the low voices through the radio communications. As a side effect, it is possible to prevent the situation for inducing the increase of the noises in the surrounding.
• When such a short range radio communication headset becomes widespread, it is possible to create a new form of the speech communication culture.
• It is also to be noted that, besides those already mentioned above, many modifications and variations of the above embodiments may be made without departing from the novel and advantageous features of the present invention. Accordingly, all such modifications and variations are intended to be included within the scope of the appended claims.

Claims (5)

1-9. (canceled)

10. A short range radio communication headset system, comprising:

a first headset for short range radio communications;

a second headset for short range radio communications which transmits speeches to the first headset; and

a speech processing device configured to apply a speech processing to the speeches transmitted by the second headset and supply processed signals to the first headset;

wherein the first headset has a receiver, an external sound detection microphone for detecting direct sounds from an external, and a transmitter for transmitting the direct sounds to the speech processing device at a first frequency;

the second headset has a transmitter for transmitting the speeches to the speech processing device at a second frequency; and

the speech processing device receives the direct sounds from the first headset and the speeches from the second headset, selectively adjusts a ratio of the direct sounds and the speeches and transmits adjusted signals to the first headset at a third frequency.

11. The headset communication system ofclaim 10, wherein the speech processing device has:

a first receiving unit for receiving the direct sounds from the first headset;

a second receiving unit for receiving the speeches from the second headset;

an adaptation processing unit for carrying out an adaptation processing using either the direct sounds or the speeches as reference signals;

a correlation processing unit for correlating the reference signals with another one of the direct sounds or the speeches that are not used as the reference signals, and extracting and outputting only necessary components; and

a transmitting unit for transmitting an output of the correlation processing unit at the third frequency.

12-14. (canceled)

15. An acoustic processing method for a short range radio communication headset system, comprising:

receiving direct sounds from an external detected by a first headset as first received signals through short range radio communications;

receiving speeches transmitted by a second headset to the first headset as second received signals through short range radio communications;

applying an adaptation processing using either the first received signals or the second received signals as reference signals;

controlling a ratio of the first received signals and the second received signals by correlating the reference signals and another one of the first received signals and the second received signals that are not used as the reference signals and extracting necessary components; and

transmitting signals with the ratio controlled by the controlling step to the first headset through the short range radio communications.

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