JP5511342B2 - Voice changing device, voice changing method and voice information secret talk system - Google Patents

Description

  The present invention relates to a voice changing device that changes voice, a voice changing method, and a voice information secret talk system including the voice changing device.

  With the enforcement of the Personal Information Protection Law, there is an increasing need to protect conversation information in banks and offices. Conventionally, sound insulation / soundproofing that physically separates the space, BGM / masking system that conceals conversational speech with other noise / music, etc. in an open plan office have been proposed.

For the purpose of concealing voice information,
(1) Masking system that masks the target speech with other stationary noise
(2) Shading system concealed by indoor background noise and air conditioning noise
(3) Sound insulation / sound insulation (the target room is spatially separated and acoustically separated)
Etc. The example (1) attempts to (forcefully) erase the presence of speech, and is positioned as energy masking. This is used, for example, in an open plan office booth or conference room.

  An example of the system (1) is reported in Non-Patent Document 1. There, a dedicated generator or speaker is installed inside the ceiling, etc., and masking sound is generated to conceal the sound. The principle is that it generates music and noise that is not in the way of conversation (contrast with conversation), conceals the contents of speech by reducing so-called S / N, and reduces clarity and intelligibility. Or to conceal the content of the conversation to the extent that it cannot be understood. The system includes a control device (signal processing device), a power amplifier, and the like that control the masking sound to the optimum level according to the conversation level, background noise, and the like.

  In addition, as an example using this technology, noise for masking was radiated from the partition into the booth, and the target space area was limited to the booth to suppress the increase in the noise level in the entire room. There is.

  An example of the system (2) is reported in Non-Patent Document 2. There are reports of “Sound Shading System” that uses indoor background noise itself and air-conditioning noise that is familiar everyday as radiating masking noise. In this system, a speaker is installed at the top of the partition for the purpose of protecting the privacy of conversation, in contrast to a visually interrupting partition for the purpose of ensuring privacy at a bank counter. A masking sound is reproduced from this speaker, thereby preventing the leakage / transmission of conversation contents to a person on the other side of the partition. The sound to be reproduced is the sound generated based on the crowds of the city or the air conditioning noise of the room.

  As an example of the system of (3), there is sound insulation partitioned as a separate room or soundproof partitioned by a partition.

KOKUYO Press Release, Sound Masking, October 18, 2006 Akiko Sugimoto, Takahiro Nakamura, Shiro Ise, “Evaluation of Sound Shading System that generates sound field in consideration of ease of conversation and privacy”, Acoustical Society of Japan Spring Meeting 2005, Proceedings, p. 817 The Institute of Electronics, Information and Communication Engineers, Auditory and Speech, 1973, p. 370-371

The inventor has recognized the following problems regarding the above-described masking / shading technique.
(I) Since the original sound emits a new sound having no context, the noise level in the indoor space can be raised with a sense of incongruity.
(II) Noise, that is, a masking sound can be heard even when the sound is not generated.
(III) By emitting another sound (noise / music) unrelated to conversation, it is possible to give a sense of incongruity to a speaker, a talker, and other people in the room.
(IV) Information concealment of speech includes the basic problem that it is difficult to succeed with noise and BGM due to the auditory nature of distinguishing and recognizing different ones (characters with similar envelopes and spectra) Is more difficult to distinguish for auditory recognition).

  As for (I), the relative level of noise necessary for completely masking the original voice is empirically about 15 dB (see Non-Patent Document 3). From this point of view, the method of concealing sound by flowing noise and music requires much louder noise and music than the original sound, and whether it is masking or shading, the room noise level Can be greatly increased.

  Regarding (II), there is a sense of incongruity that a sound is produced even when there is no utterance. In the first place, playing noise and music when there is no utterance is useless from the viewpoint of concealing conversation content. It is not only useless, but it also increases the room equivalent noise level (Laeq: A-weighted equivalent sound level = root mean square sound pressure level of the audio signal corrected by A characteristics, that is, average noise level). Can result. Even when music is played instead of noise, it is difficult to distinguish from general BGM.

  In addition, the approach (3) is considerably large in cost and hinders a feeling of opening, and is not suitable for use in an open plan office or the like.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a technique for concealing audio content while suppressing an increase in noise level and listener discomfort.

  One embodiment of the present invention relates to a sound changing device. The voice change device includes a partial extraction unit that extracts a change target part from a voice signal, a partial change unit that changes the change target part extracted by the partial extraction unit, and at least a change target part that has been changed by the partial change unit. And an output unit for outputting to the audio output means.

  According to this aspect, the change target portion of the audio signal can be changed and then output to the audio output means. The audio output means may output an audio signal in which the change target portion is changed as a sound.

  Another aspect of the present invention is a speech information secret talk system. The voice information secret speech system includes a sound collecting unit that receives an uttered voice and generates a voice signal representing the voice, a voice changing device that changes a voice signal generated by the sound collecting unit, and a voice changed by the voice changing device. Voice output means for converting the signal into voice and outputting the voice to a region where the uttered voice can be heard. The voice changing device includes a partial extraction unit that extracts a change target portion from the voice signal generated by the sound collecting unit, a partial change unit that changes the change target portion extracted by the partial extraction unit, and at least the partial change unit. And an output unit for outputting the changed portion to be changed to the audio output means.

  According to this aspect, it is possible to change the change target part of the audio signal representing the uttered voice and output it as a sound to an area where the uttered voice can be heard.

  It should be noted that any combination of the above-described constituent elements, or those obtained by replacing the constituent elements and expressions of the present invention with each other between apparatuses, methods, systems, computer programs, recording media storing computer programs, and the like are also included in the present invention. It is effective as an embodiment of

  ADVANTAGE OF THE INVENTION According to this invention, the content of an audio | voice can be concealed, suppressing the increase in a noise level and a listener's discomfort.

It is explanatory drawing which divides into a category the conventional approach regarding masking, and the approach which concerns on embodiment. It is a perspective view which shows typically the booth provided with the audio | voice information secret talk system which concerns on embodiment. It is a block diagram which shows typically the function and structure of the audio | voice information confidential system of FIG. It is a side view which shows the structure of the IT partition of FIG. It is a block diagram which shows the function and structure of the SD controller part of FIG. It is a data structure figure which shows the consonant library of FIG. It is a wave form diagram which shows the waveform of the audio | voice signal showing a maskee. It is a wave form diagram which shows the waveform of the audio | voice signal produced | generated by processing the audio | voice signal of FIG. 7 in a consonant only substitution mode in the SD controller part. It is explanatory drawing which shows the breakdown of a consonant replacement process. It is a flowchart which shows a series of processes in an SD controller part and a speaker. It is a block diagram which shows typically the function and structure of the audio | voice information confidential system which concerns on a 1st modification. It is a block diagram which shows typically the function and structure of the audio | voice information confidential system which concerns on a 2nd modification. It is a wave form diagram which shows the waveform of the audio | voice signal which time-reversed the audio | voice signal of FIG. 7 in the syllable group unit divided by the energy envelope in SD controller part.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

  Particularly in offices and the like, it is desirable to conceal only the voice information, that is, the voice content without impairing the openness and smoothness of communication of the open plan space. However, the conventional technology using BGM and masking basically adds another sound having a different property from that of speech, so that there is a dislike of increasing the sense of incongruity and background noise in the room. The embodiment of the present invention conceals the content of the conversation without raising the background noise by changing the structure of the sound signal itself collected by a microphone or the like, ideally only the content of the conversation, A smooth and comfortable secret story environment is realized.

  FIG. 1 is an explanatory diagram showing a conventional approach related to masking and an approach according to an embodiment divided into categories. (A) is SR (Sound Reinforcement) / PA (Public Address) using electroacoustics. These are conventional technologies that increase the volume and clarity and “make them sound better”. (F) is Sound Insulation, which is a conventional technique for acoustically separating a space and making it “not audible” as much as possible. On the other hand, the approach according to the embodiment is SD (Sound Deformation) of (e), and by processing and outputting the original voice of the conversation person, the conversation content is not made inaudible but not heard. It is a kind of voice information disturbance technology. Further, (b) EM, (c) SS, and (d) IM according to the prior art can increase the noise level in the room or the target space region to increase the unpleasantness and discomfort, In SD, there is almost no volume increase.

  The main standpoint of the embodiment of the present invention is the recognition of the present inventor that language recognition and understanding depend largely on the consonant part of speech, particularly in the case of Japanese. If this consonant part changes, for example, “KUMO” becomes “RUTO” and cannot be understood as words.

In the embodiment of the present invention, paying attention to such aspects of speech recognition / understanding, particularly the consonant part of the original speech is changed / deleted / replaced. Since the processing of the consonant part is the main, the increase in the sound pressure level (volume) is small compared to the original voice. Further, in order to further reduce the overall volume of the processed voice (hereinafter referred to as a masker) added to the original voice (hereinafter referred to as a maskee), the following combination / ingenuity is possible.
(I) In generating a masker, the vowel part is replaced with silence, and only the processed consonant part is output at the original timing.
(Ii) ANC (Active Noise Control) or parameter-fixed PNC (Passive Noise Control) technology is used in combination to enhance the masker's information hiding effect.

FIG. 2 is a perspective view schematically showing the booth 2 in which the audio information secret system 100 according to the embodiment is provided. FIG. 3 is a block diagram schematically showing the function and configuration of the speech information secret system 100 of FIG.
The voice information secret story system 100 is provided in a booth 2 partitioned by a simple partition, such as a bank consultation counter. The audio information secret system 100 includes a microphone Mic, an SD controller unit SD, two power amplifiers PA, and two speakers SP. The speaker SP and the SD controller unit SD may be incorporated in the IT partition 4 that visually separates the booths.

  A customer 6 who has a conversation with a counselor is a speaker. The speaker's maskee H ′ (t) is collected by a microphone Mic provided at or near the counter portion. The maskee H ′ (t) collected by the microphone Mic is converted into an audio signal and sent to the SD controller unit SD. The consonant part of the audio signal is changed, deleted, or replaced by the SD controller unit SD. The audio signal that has undergone the processing in the SD controller section SD is output as a masker H (t) from the speaker SP to the left and right adjacent booths 2 'via the power amplifier PA.

  Since Muskie H '(t) goes around the air in the adjacent booth 2', the voice of the customer 6 is heard by a listener 8 (a different person from the customer 6) in the adjacent booth 2 '. sell. However, in the present embodiment, the masky H ′ (t) that leaks through the air is combined with the masker H (t) and reaches the listener 8 in the adjacent booth 2 ′. Therefore, the listener 8 cannot correctly recognize the consonant part of the maskee H ′ (t) due to the disturbance by the masker H (t). As a result, the listener 8 cannot understand the content of the conversation included in the maskee H ′ (t).

  FIG. 4 is a side view showing the configuration of the IT partition 4 of FIG. The IT partition 4 has a laminated structure in which a first sound absorbing layer 42, a sound insulating layer 44, and a second sound absorbing layer 46 are laminated in this order. Each of the first sound absorbing layer 42 and the second sound absorbing layer 46 is a glass wool layer having a thickness of 20 mm. The sound insulation layer 44 is a gypsum board having a thickness of 12 mm.

  FIG. 5 is a block diagram showing the function and configuration of the SD controller unit SD of FIG. Each block shown here can be realized in hardware by an element such as a CPU (central processing unit) or a mechanical device, and in software by a computer program or the like. Describes functional blocks realized by collaboration. Accordingly, it is understood by those skilled in the art who have touched this specification that these functional blocks can be realized in various forms by a combination of hardware and software.

  The SD controller unit SD includes a storage device 10, an A / D unit 20, a partial extraction unit 30, a partial change unit 90, a D / A unit 70, a noise generation unit 80, a consonant library update unit 82, A vowel library updating unit 84. The storage device 10 includes a consonant library 12, a vowel library 14, and a common library 16. The partial extraction unit 30 includes a voice discrimination unit 36, a consonant extraction unit 32, and a vowel extraction unit 34. The partial change unit 90 includes a consonant processing unit 40 and a vowel processing unit 50.

  The consonant library 12 stores waveform data for each type of consonant part. The vowel library 14 stores waveform data for each type of vowel part. The common library 16 stores predetermined sample waveform data for each type of consonant part. The sample waveform data of the consonant part stored in the common library 16 is classified into male, female, child, adult and the like.

  The SD controller unit SD has at least two operation modes: a consonant only replacement mode and a consonant vowel replacement mode. The function of the block related to each operation mode will be described below.

(1) Consonant-only replacement mode The masky H ′ (t) collected by the microphone Mic is converted into an audio signal, and the audio signal is input to the A / D unit 20 via a microphone amplifier (not shown). The A / D unit 20 converts an audio signal that is an analog signal into a digital signal. The voice discriminating unit 36 discriminates a consonant part and a vowel part of the voice signal by comparing the waveform of the voice signal digitized by the A / D unit 20 with a past speech voice waveform. The consonant extraction unit 32 extracts a consonant part using the determination result.

  The consonant library updating unit 82 accumulates the waveform data of the consonant part extracted by the consonant extracting unit 32 in the consonant library 12 for each type. Here, the classification of the consonant part is performed based on its duration, spectrum, statistical processing and the like. As described above, the waveform data of the consonant portion stored in the consonant library 12 is gradually replaced with highly accurate data from the start of the conversation by sequential processing.

  Based on the consonant part extracted by the consonant extraction unit 32, the noise generation unit 80 generates consonant noise having a spectrum similar to that.

  The consonant processing unit 40 processes the consonant part extracted by the consonant extraction unit 32 in the audio signal. The consonant processing unit 40 replaces the consonant part extracted by the consonant extraction unit 32 with another consonant part having substantially the same length selected from the consonant library 12. When there are a plurality of replacement candidates, the consonant processing unit 40 performs replacement randomly and so that each combination has a substantially equal probability. Here, as an example of the length of the consonant part, the duration of the consonant part corresponding to “s” is relatively long, and the duration of the consonant part corresponding to “t” or “p” is short. Sometimes.

  Note that the consonant processing unit 40 may replace the consonant part extracted by the consonant extraction unit 32 with the consonant noise generated by the noise generation unit 80 instead of using the consonant library 12 to replace the consonant part. . In this case, the randomness of the synthesized speech between the maskee H ′ (t) and the masker H (t) is further increased. In addition, the consonant processing unit 40 may delete the consonant part extracted by the consonant extraction unit 32 instead of replacing the consonant part using the consonant library 12.

  There is a possibility that the consonant portion collected from the voice of the utterer is not sufficiently accumulated in the consonant library 12 for several seconds to several tens of seconds (hereinafter referred to as an utterance start period) from the start of the utterance. Therefore, during this utterance start period, the consonant processing unit 40 selects the corresponding consonant part from the common library 16 and replaces it with the consonant part extracted by the consonant extraction part 32. Alternatively, during the utterance start period, the consonant processing unit 40 replaces the consonant part extracted by the consonant extraction unit 32 with the consonant noise generated by the noise generation unit 80. Alternatively, during the utterance start period, the consonant processing unit 40 inverts the consonant part extracted by the consonant extraction unit 32 in the time direction.

  These consonant partial modification algorithms used during the utterance start period are less natural than using the consonant library 12 of the speaker himself. However, since it is only a short time after the start of utterance, it does not matter so much.

  The D / A unit 70 converts the audio signal processed by the consonant processing unit 40 into an analog audio signal for driving the speaker SP and outputs the analog audio signal to the power amplifier PA. In particular, the D / A unit 70 converts an audio signal including a consonant part replaced by the consonant processing unit 40 and an unmodified vowel part corresponding to the consonant part into an analog signal and outputs the analog signal.

Note that the time from when the musky H ′ (t) is collected by the microphone Mic until it is processed by the SD controller unit SD and the corresponding masker H (t) is output from the speaker SP, that is, the SD processing time T _SD is T + t. It is supposed to be within. Here, T is the time from when Muskie H '(t) is issued until it reaches the listener 8, and t is noticeable when the Muskie H' (t) and Masker H (t) are at the listener 8 position. This is the delay time that does not generate a simple echo, or the maximum delay time that the synthesized speech that reaches the listener 8 becomes unintelligible for the listener 8. A specific value of t is determined by experiment, but is typically about 100 ms.

In order to conceal information by synthesizing Masky H '(t) and Masker H (t) at the listener's 8 position, the SD processing in the SD controller unit SD must be performed in real time or near real time as described above. I must. The accuracy of processing such as extraction and replacement / inversion of consonant parts must be sacrificed due to the existence of this time constraint, that is, the SD processing time T _SD must be shorter than T + t, which is a short time. There is also. However, the purpose of this embodiment is to reduce the intelligibility and intelligibility of speech, and the accuracy of the assumed / scheduled processing itself is not the purpose. Therefore, in this embodiment, if the condition that it becomes difficult to understand the meaning content of the maskee H ′ (t) due to the superposition of the maskers H (t), the processing accuracy does not become a big problem. This is because there are an infinite number of “conditions that make it difficult to understand the semantic content”.

(2) Vowel replacement mode In this mode, the vowel part is also changed in addition to the above-described change of the consonant part. The vowel extraction unit 34 extracts a vowel part from the voice signal from which the consonant part is extracted by the consonant extraction unit 32.

  The vowel library update unit 84 stores the waveform data of the vowel part extracted by the vowel extraction unit 34 in the vowel library 14 for each type. Here, the vowel part is classified based on its duration, spectrum, statistical processing, and the like. In this way, the waveform data of the vowel part stored in the vowel library 14 is gradually replaced with highly accurate data from the start of the conversation by sequential processing.

  The noise generation unit 80 generates vowel noise having a spectrum similar to that of the vowel part extracted by the vowel extraction unit 34.

  The vowel processing unit 50 processes the vowel part extracted by the vowel extraction unit 34 in the audio signal after the consonant part is processed by the consonant processing unit 40. In particular, when it is necessary to suppress an increase in noise level as much as possible, the vowel processing unit 50 replaces the vowel part extracted by the vowel extraction part 34 with a silent part. In this case, the masker H (t) output via the D / A unit 70 and the speaker SP has a structure having a silent part sandwiched between a consonant part and a consonant part. That is, the consonant part of the masker H (t) is connected to the vowel part of the synchronized masky H ′ (t) to form one phoneme. As a result, the overall sound volume is reduced by the vowel part silenced by the masker H (t), and the indoor noise level is also reduced.

  The vowel processing unit 50 may perform library-based replacement instead of replacing the vowel part with a silent part. That is, the vowel processing unit 50 may replace the vowel part extracted by the vowel extraction part 34 with another vowel part selected from the vowel library 14. When there are a plurality of replacement candidates, the vowel processing unit 50 performs replacement so that each combination has a substantially equal probability. The vowel part changing algorithm in the utterance start period is the same as that of the consonant part.

  Alternatively, the vowel processing unit 50 may replace the vowel part extracted by the vowel processing unit 50 with the vowel noise generated by the noise generation unit 80 instead of replacing the vowel part with a silent part. In this case, the randomness of the synthesized speech of the maskee H ′ (t) and the masker H (t) is further increased.

  Further, the order of processing of consonant vowels, that is, the order of processing in the consonant processing unit 40 and processing in the vowel processing unit 50 may be switched.

  FIG. 6 is a data structure diagram showing the consonant library 12. The consonant library 12 stores a consonant 112 as a phoneme and waveform data 114 of the consonant in association with each other. The vowel library 14 and the common library 16 also have the same data structure as the consonant library 12.

  FIG. 7 is a waveform diagram showing the waveform of an audio signal representing the maskee H ′ (t). The waveform in FIG. 7 is obtained by converting the original voice “ANO KARETOWA SO-TONAGAINDAYONE ZITSUWA” into a voice signal with the microphone Mic. The vertical axis in FIG. 7 represents signal intensity in arbitrary units, and the horizontal axis represents time. In FIG. 7, each region divided by vertical broken lines corresponds to a phoneme, and the corresponding phoneme is clearly shown in Roman letters. “-” Represents a voice pause unit. The energy envelope 102 is shown as a solid line. Here, the energy envelope is obtained by multiplying a voice sample by a time constant of several tens of milliseconds in the square sound pressure region and taking a square root.

  Table 1 shows vowels, consonants, and silences in FIG. A certain time before the start of voice is defined as the time origin (t = 0).

The distinction between consonants, vowels, and silence can be determined by energy, the number of zero crossings, the first coefficient (spectral slope) of PARCOR (PARtial auto-CORrelation), and the like.

FIG. 8 is a waveform diagram showing a waveform of an audio signal generated by processing the audio signal of FIG. 7 in the consonant only replacement mode in the SD controller unit SD. This is a consonant part in which the consonant part indicated by the section 104 is replaced. For these replacements, the cut-out time length and re-insertion level (dB) are adjusted.
The energy envelope 106 after the replacement is indicated by a solid line. When comparing the energy envelope 102 of FIG. 7 and the energy envelope 106 of FIG. 8, it can be seen that there is not much change. In other words, there is not much change in voice intonation and intonation. However, when the audio signal of FIG. 8 is converted into sound by the speaker SP and output as a masker H (t), the listener 8 site synthesizes and hears the maskey H ′ (t) and the masker H (t), Its meaning is difficult to understand. In other words, it is often “I don't know” (may be heard by other sounds).

  FIG. 9 is an explanatory diagram showing a breakdown of the upper consonant replacement process. FIG. 9 shows how to replace which consonant part in the audio signal of FIG. In this consonant replacement process, consonant parts in the audio signal of FIG. 7 are replaced.

  FIG. 10 is a flowchart showing a series of processes in the SD controller unit SD and the speaker SP. The A / D unit 20 acquires a voice signal representing the speech voice from the microphone Mic (S202). The partial extraction unit 30 extracts a change target part from the acquired audio signal (S204). The part changing unit 90 changes the extracted change target part (S206). The speaker SP converts at least the changed part to be changed into a sound and outputs it (S208).

  The operation of the speech information secret system 100 having the above configuration will be described. Consider a case in which a customer 6 sits in a bank booth 2 and consults with a bank counselor about, for example, a loan. At this time, it is assumed that there is a listener 8 in the adjacent booth 2 ′ next to the booth 2 and an application for opening an account is being made. Customer 6 explains the circumstances of applying for a loan, such as the worsening of the cash flow of his business. Of course, it is better for the listener 8 not to leak such a story. In particular, in the speech information secret speech system 100 according to the present embodiment, the listener 6 mainly converts the consonant part of the speech voice of the customer 6. Therefore, the listener 8 cannot understand the utterance content of the customer 6. In addition, when there is no utterance by the customer 6, there is substantially no output from the speaker SP to the adjacent booth 2 ', so that the noise level in the adjacent booth 2' is not increased unnecessarily.

  In the above-described embodiment, examples of the storage device 10 are a hard disk and a memory. In addition, based on the description of the present specification, each block is stored in a CPU (not shown), an installed application program module, a system program module, a memory that temporarily stores data read from the hard disk, or the like. It will be understood by those skilled in the art who have touched this specification that it can be realized.

  According to the speech information secret system 100 according to the present embodiment, the following operational effects can be obtained.

(1) According to the speech information secret system 100 according to the present embodiment, the content, that is, the information included in the conversation speech is concealed instead of concealing or deleting the presence of the conversation itself. In this regard, the inventor has recognized the following.
In open-plan offices, bank and securities company lobbies, especially in customer service counters partitioned by simple partitions, if the contents of the conversation cannot be understood by anyone other than the person who is speaking, the content of the conversation will be hidden. Well, its purpose is fulfilled. In other words, the voice itself may be heard as long as the content of the conversation is not leaked. Rather, when the presence of a speaker can be visually recognized, it is more natural to preserve the voice spectrum and energy envelope (sound quality, intonation, and intonation). The voice information secret system 100 according to the present embodiment corresponds to the above viewpoints and needs, and conceals conversation contents in a more natural manner.

  (2) The masker H (t) is created based on the speaker's own maskee H ′ (t), focusing on its consonant part, and is output from the speaker in parallel with the original voice. Therefore, particularly in the consonant-only replacement mode, the spectrum and energy envelope of the maskee H ′ (t) can be preserved even if it becomes the masker H (t). As a result, since the spectrum and intonation of the masker H (t) are almost the same as those of the maskee H '(t), the sense of incongruity is naturally received by the listener.

  (3) The masker H (t) is generated by replacing only the consonant part with respect to the maskee H ′ (t), or replacing the vowel part with a silent part after replacing the consonant part. Therefore, it is possible to suppress the increase in the volume (sound pressure level) of the masker H (t) and hence the indoor noise level as much as possible.

  (4) No masker H (t) is output when there is no maskee H '(t) on the time axis, that is, when there is no conversation. That is, both overlap substantially in time. Therefore, an increase in the room noise level due to the masker H (t) during “no sound” when no sound is generated can be suppressed.

  (5) Dissipating a feeling of discomfort due to intermittent maskers or level fluctuations (disrupted when the conversation is stopped to reduced level) that may occur when using conventional technology, or other sounds (noise / music) that are not related to conversation This reduces the sense of discomfort for speakers, conversers, and other people in the room.

  (6) With respect to the physical sound insulation and private room formation in the prior art, no spatial blockage or movement is required, so that a sense of openness and communication are less likely to be hindered.

  (7) Since the SD controller unit SD and the speaker SP are incorporated in the IT partition 4, the installation and installation of the system can be greatly simplified. In some cases, the microphone Mic may be incorporated in the IT partition 4. In this case, it is further simplified.

  (8) The IT partition 4 itself is subjected to sound absorption processing. Therefore, sound leakage to the adjacent booth can be reduced while increasing the clarity of the conversation voice in the booth.

  (9) The masker H (t) becomes a signal that is not so correlated with the masky H ′ (t) (original voice) by processing such as replacement / deletion. Therefore, abnormalities due to feedback such as howling are less likely to occur during the operation of the speech information confidential system 100.

  Heretofore, the configuration and operation of the audio information secret system 100 according to the embodiment and the SD controller unit SD included therein have been described. This embodiment is an exemplification, and it is understood by those skilled in the art that various modifications can be made to each component and combination of processes, and such modifications are within the scope of the present invention.

  In the embodiment, the case where the masker H (t) is output from one side of the adjacent booth has been described, but the present invention is not limited to this. For example, the masker H (t) may be output from the left and right sides of the adjacent booth by signal addition. FIG. 11 is a block diagram schematically showing the function and configuration of the audio information secret system according to the first modification. The audio information secret system according to the first modification includes a microphone Mic, an SD controller unit SD, four speakers SPa to SPd (SPd is not shown), and four power amplifiers PAa to PAd (PAd is not shown). Four adders 210a to 210d (210d not shown).

The audio signal that has undergone the processing in the SD controller unit SD is the adder 210a corresponding to the left speaker SPa of the booth 2, the adder 210b corresponding to the right speaker SPb of the booth 2, and the adjacent booth adjacent to the left of the booth 2. The signal is input to the adder 210c corresponding to the left speaker SPc of 2 ′ and the adder 210d (not shown) corresponding to the right speaker SPd (not shown) of the adjacent booth adjacent to the right of the booth 2. The audio signals input to the adders 210a to 210d are output from the speakers SPa to SPd via the corresponding power amplifiers PAa to PAd. The adder acquires and adds the audio signal that has undergone processing in the SD controller unit SD from the booths adjacent to the booth to which the speaker to which the speaker is connected outputs audio.
According to this modification, since the masker H (t) is output from both the left and right sides of the adjacent booth 2 ′, the conversation contents in the booth 2 are difficult to be transmitted to the listener 8.

Further, a PNC (Passive Noise Controller) may be used in combination to reduce the level of the maskee H ′ (t). The PNC intends to use a known ANC (Active Noise Control) adaptively at the time of adjustment, and to fix and use the set parameters at the time of operation.
FIG. 12 is a block diagram schematically showing the function and configuration of the speech information secret system according to the second modification. In this modification, the SD controller unit SD in FIG. 11 is replaced with a part surrounded by a broken line in FIG. In this part, the SD controller unit SD and the PNC unit PNC are provided in parallel, and an audio signal from the microphone Mic is input to the SD controller unit SD and the PNC unit PNC. A switch SW1 is provided on the output side of the SD controller unit SD, and the operation of the SD controller unit SD is controlled by the switch SW1. The output of the switch SW1 and the output of the PNC unit PNC are added by an adder 406 and output as sound from the speaker SP via the power amplifier PA.

  In this modification, the head torso simulator HATS (HATS: Head and Torso Simulator) connected to the sound source 402 via the amplifier 404 is placed at the speaker position P, and the PNC unit PNC is identified. The switch SW1 is opened to turn off the operation of the SD controller unit SD, and an appropriate audio signal is emitted from the HATS so that the output of the microphone Mic ′ placed at the listener position Q in the adjacent booth 2 ′ is minimized. System identification is performed by adaptively operating.

At this time, the impulse response including the microphone Mic and the speaker SP is −h (x), and the absolute value is substantially equal to that h (x) between the PNC speaker and the listener. Thereafter, the switch SW1 is closed, and the PNC unit is operated with the identified parameters fixed. Then, since the positions P and Q of the speaker and the listener and the positions of the microphone Mic and the speaker SP are substantially fixed, the level of the maskee H ′ (t) is effectively reduced, and the masker H (t) is dominant. Become. As a result, the effect of information masking is enhanced. If the level of the masker H (t) is lowered as necessary, the level of the entire system including the maskee H ′ (t), that is, the noise level in the room can be further reduced.
Note that the PNC function described above may be incorporated in a computer in which the SD controller unit SD is incorporated.

  Although ANC / PNC is an existing technology, it is not suitable for controlling a wide sound field all over three dimensions. On the other hand, in the case where the listener's head is present at a substantially fixed position in a narrow space surrounded by the partition of the counter, the sound reduction means is effective even in three dimensions.

  In the embodiment, the case where the audio signal is divided into the consonant part and the vowel part and at least the consonant part is changed has been described. However, the present invention is not limited to this. For example, the partial extraction unit of the SD controller unit may divide the audio signal into syllable groups found in the energy envelope of the masky H ′ (t). And the partial change part of SD controller part SD may reverse in the time direction for every syllable group. FIG. 13 is a waveform diagram showing the waveform of the audio signal obtained by time-reversing the audio signal of FIG. 7 in units of syllable groups partitioned by the energy envelope in the SD controller unit. The portion indicated by the partition 108 is a portion that is time-reversed. Here, time reversal is performed in units of substantially one peak of the energy envelope 110 indicated by a solid line.

When the energy envelope 102 of FIG. 7 is compared with the energy envelope 110 of FIG. In other words, there is almost no change in voice intonation and intonation. However, when the audio signal of FIG. 13 is converted into audio by the speaker SP and output as a masker H (t), the listener 8 site can synthesize and hear the masky H ′ (t) and the masker H (t), Its meaning is difficult to understand. In other words, it is often “I don't know” (may be heard by other sounds).
Moreover, according to this modification, the process in the SD controller unit is further simplified as compared with the case of consonant replacement in the embodiment. Accordingly, the processing time is shortened. Furthermore, according to experiments conducted by the present inventors, it was confirmed that the information disturbance effect due to time reversal is comparable to that due to consonant replacement.
A further advantage of this modification is that a library is not required, so that a sufficient information disturbance effect can be obtained from the start of conversation.

  In addition, the SD controller unit cuts out and inverts the audio signal at a constant cycle, a cycle that slightly fluctuates randomly with respect to the fixed cycle, or a section in which the envelope of the original speech can be regarded as a group. You may return to the position. At this time, this process may be sequentially repeated so that the delay is within T + t with respect to the maskee H ′ (t). In this case, it is possible to obtain the same function and effect as those of the voice information secret system 100 according to the embodiment.

  In replacement or deletion of a change target portion such as a consonant portion in the embodiment, a time window such as a Hanning window or zero cross detection may be used together to remove a click sound that may occur at the time of clipping. In this case, the uncomfortable feeling that can be given to the listener 8 or the people in the room is further reduced.

Although the present invention has been described based on the embodiments, the embodiments merely show the principle and application of the present invention, and the embodiments are defined in the claims. Needless to say, many modifications and arrangements can be made without departing from the spirit of the present invention.
For example, these audio processes take some time, but in addition to this, it is possible to add a time delay to radiate the processed audio, or to radiate a plurality of processed audio on the original audio. It is an example.

  2 booths, 4 IT partitions, 6 customers, 8 listeners, 10 storage devices, 30 partial extraction units, 90 partial modification units, 100 voice information secret talk systems, SD SD controller units, SP speakers, Mic microphones.

Claims (7)

A partial extraction unit that extracts a change target part in units of substantially one mountain of an envelope of the waveform of the audio signal from the audio signal;
A partial change unit for changing the change target part extracted by the partial extraction unit;
An output unit that outputs at least the change target portion changed by the partial change unit to an audio output unit ;
The audio signal represents speech,
The change target portion output by the output unit is converted into a sound by the sound output means and output to an area where the uttered sound can be heard . The voice change device according to claim 1, wherein the partial change unit reverses the change target portion extracted by the partial extraction unit in a time direction. A sound collecting means for receiving the uttered voice and generating a voice signal representing the voice;
A sound changing device for changing a sound signal generated by the sound collecting means;
Voice output means for converting the voice signal changed by the voice changing device into voice and outputting the voice signal to an area where the uttered voice can be heard; and
The voice changing device is
A partial extractor for extracting a change target portion in units of substantially one mountain of the envelope of the waveform of the sound signal from the sound signal generated by the sound collecting means;
A partial change unit for changing the change target part extracted by the partial extraction unit;
And an output unit that outputs at least the change target portion changed by the partial change unit to the voice output unit. 4. The voice information secret system according to claim 3 , wherein the voice changing device and the voice output means are incorporated in a booth partition. 5. The voice information secret speech system according to claim 4 , wherein the partition is subjected to sound absorption processing. Obtaining an audio signal;
Extracting a change target portion in units of substantially one mountain of an envelope of the waveform of the audio signal from the acquired audio signal;
Changing the extracted change target part; and
Viewed contains a step for converting at least a modified change target area to a voice, and
The audio signal represents speech,
In the outputting step, the change target portion is output to an area where the uttered voice can be heard . A function to extract a change target portion in units of substantially one peak of the envelope of the waveform of the audio signal from the audio signal;
A function to change the extracted change target part,
A Turkish computer program to realize the function of outputting to the audio output means at least changed change target area, to the computer,
The audio signal represents speech,
The computer program characterized in that the change target portion output in the output function is converted into speech by the speech output means and output to an area where the uttered speech can be heard .