JP5954348B2 - Speech synthesis apparatus and speech synthesis method - Google Patents

Description

  The present invention relates to a speech synthesizer and a program.

In recent years, the following have been proposed as speech synthesis techniques. That is, by synthesizing and outputting speech corresponding to the user's speech tone and voice quality, a technique for sounding more humanly (see, for example, Patent Document 1), analyzing the user's speech, A technique for diagnosing a health condition or the like (see, for example, Patent Document 2) has been proposed.
In addition, a voice dialogue system that recognizes a voice input by a user and outputs a content specified in a scenario by voice synthesis to realize a voice dialogue with the user has been proposed (for example, Patent Document 3). reference).

JP 2003-271194 A Japanese Patent No. 4495907 Japanese Patent No. 4832097

By the way, it is assumed that a dialogue system that combines the above-described voice synthesis technology and a voice dialogue system and retrieves data and outputs it by voice synthesis in response to a user's voice question. In this case, a problem has been pointed out that the voice output by the voice synthesis feels unnatural to the user, specifically, the machine sometimes feels roaring.
The present invention has been made in view of such circumstances, and one of its purposes is to give the user a natural feeling, specifically, a positive impression or a bad impression on the user. Is to provide a speech synthesis apparatus and a speech synthesis method .

  In examining the man-machine system that outputs (answers) the answers to the questions from the users by speech synthesis, the present inventor firstly examines what kind of dialogue is made between people other than linguistic information. We focused on non-verbal information (non-verbal information), especially the pitch (frequency) that characterizes dialogue.

Here, as a dialogue between people, a case where the other person (b) responds to a question (question) by one person (a) will be considered. In this case, when a asks a question, not only a but also b trying to answer the question often leaves a strong impression of the pitch in a certain section of the question. b, when replying with consent, approval, or affirmation, the pitch of the question that remains in the impression, for example, the pitch of the ending or beginning of the word Speak to be in a Kyowa pitch. A who has heard the answer has a relationship between the pitch that remains in the impression about his question and the pitch of the part that characterizes the answer to the question. The present inventor thought that he had a good impression.
In addition, people have been communicating with each other since ancient times without language, but it is presumed that volume and pitch played a very important role in communication between people in such an environment. doing. In today's language-developed world, the pitch communication has been forgotten, but because the “predetermined pitch relationship” from ancient times is engraved in DNA, it is “somehow comfortable”. I guess it feels.

  Explaining the dialogue between people with a specific example, for example, when a asks the question “Oh, right?”, A and b have strong willingness and confirmation among the questions. The pitch of the ending “Sho” appears in the memory. In this state, when b tries to affirmatively answer “A, yes” to the question, the part characterizing the answer with respect to the pitch of “Sh” that remains in the impression, for example, the ending Answer “Yes, yes” so that the pitch of “Yes” is in the above relationship.

FIG. 2 shows a formant in such an actual dialogue. In this figure, the horizontal axis is time, the vertical axis is frequency, and the spectrum shows a state where the intensity increases as it becomes white.
As shown in the figure, a spectrum obtained by frequency analysis of human speech appears as a plurality of peaks that move in time, that is, formants. Specifically, a formant corresponding to “Yeah?” And a formant corresponding to “Ah, yes” each appear as three peak bands (white band-like portions moving along the time axis).
When attention is paid to the first formant having the lowest frequency among these three peak bands, the frequency of the code A (the central part) corresponding to “Sho” of “Oh, right?” Is approximately 400 Hz. On the other hand, for the code B, the frequency of the code B corresponding to “Yes” of “A, Yes” is approximately 260 Hz. For this reason, it can be seen that the frequency of the code A is approximately 3/2 with respect to the frequency of the code B.

  The relationship that the frequency ratio is 3/2 is the same octave “de” for “so” or “la” one octave lower for “mi”. As will be described later, there is a complete 5 degree relationship. This frequency ratio (predetermined relationship between pitches) is a preferred example, but various examples can be given as will be described later.

  FIG. 3 is a diagram showing a relationship between a pitch name (floor name) and a human voice frequency. In this example, the frequency ratio when the fourth octave “do” is used as a reference is also shown, and “so” is 3/2 as described above when “do” is used as a reference. Further, the frequency ratio when the third octave “La” is used as a reference is also illustrated in parallel.

  In this way, in the dialogue between people, it can be considered that the pitch of the question and the pitch of the answer to be answered are not irrelevant but have the above-described relationship. Then, the present inventor analyzed many dialogue examples and statistically aggregated evaluations by many people to prove that this idea is roughly correct. Based on such considerations and support, when considering a dialogue system that outputs (answers) answers to questions from users by speech synthesis, the following configuration is achieved to achieve the above objectives for speech synthesis: It was.

That is, in order to achieve the above object, a speech synthesizer according to an aspect of the present invention analyzes a speech input unit that inputs a question based on a speech signal, and a pitch of a specific first section of the question. A pitch analysis unit, an acquisition unit that acquires an answer to the question, and a pitch of a specific second section of the acquired answers that are in a predetermined relationship with the pitch of the first section And a voice synthesizer that changes the output so as to be high.
According to this aspect, it is possible to prevent an unnatural feeling from being accompanied by an answer that is synthesized by speech in response to a question based on an input speech signal. Note that the answer is not limited to a specific answer to the question, but also includes a companion (interjection) such as “Yes”, “I see”, “I see”. In addition to human voices, answers include animal calls such as “bow” and “meow”. That is, the answer and the voice here are concepts including not only a voice uttered by a person but also an animal cry.

  In the above aspect, it is preferable that the first section is a ending of the question and the second section is a beginning or ending of the answer. As described above, the section characterizing the impression of the question is the ending of the question, and the section characterizing the impression of the answer is often the beginning or the ending of the answer.

Moreover, it is preferable that the predetermined relationship is a relationship of Kyowa intervals excluding perfect 1 degree. Here, “Kyowa” means a relationship in which when a plurality of musical sounds are generated at the same time, they are fused and well harmonized, and these pitch relationships are called Kyowa pitches. The degree of cooperation is higher as the frequency ratio (frequency ratio) between two sounds is simpler. The simplest frequency ratios of 1/1 (perfect 1 degree) and 2/1 (perfect 8 degree) are called absolute consonance pitches, and 3/2 (perfect 5 degree) and 4/3 (perfect) 4 degrees) and is called the perfect harmony pitch. 5/4 (3 degrees long), 6/5 (3 degrees short), 5/3 (6 degrees long) and 8/5 (6 degrees short) are called incomplete harmony intervals, and all other frequency ratios This relationship (long and short 2 degrees and 7 degrees, various increase / decrease intervals, etc.) is called dissonance interval.
If the pitch at the beginning or end of the answer is the same as the pitch at the end of the question, it is thought that the dialogue is accompanied by an unnatural feeling. In the relationship, one complete degree is excluded.

  In the above aspect, the predetermined relationship between the pitch of the question and the pitch of the answer may be a pitch relationship within the following range, as well as the Kyowa interval except for a perfect 1 degree. That is, the speech synthesizer changes and outputs the pitch of the second section so that the pitch of the second section is in the range of one octave above and below, except for the same pitch. The structure to do may be sufficient. This is based on the knowledge that when the pitch of the answer is more than one octave above and below the pitch of the question, the above-mentioned Kyowa pitch relationship is not established, and the conversation becomes unnatural. Even in this configuration, if the pitch of the answer and the pitch of the question are the same, the dialogue becomes unnatural as described above, so it is excluded from the pitch relationship within the range of one octave above and below. .

  In the above aspect, the speech synthesizer changes and outputs the pitch of the second section so that the pitch has a relationship of 5 degrees below the pitch of the first section. The structure which does is preferable. According to this configuration, it is possible to give a good impression to the user who has made a question about the answer that is answered to the question.

  In the above aspect, the speech synthesizer attempts to change the pitch of the second section to change the pitch to have a predetermined relationship with the pitch of the first section. If the pitch to be changed is lower than the predetermined threshold pitch, the pitch to be changed is further shifted to a pitch one octave higher, or if the pitch to be changed is higher than the predetermined threshold pitch. The pitch to be changed may be shifted to a pitch one octave below. According to this configuration, when the pitch of the second section in the answer is to be changed, if the pitch is lower (if higher) than the predetermined threshold pitch, the pitch is increased by one octave (lower). Since the shift is performed, for example, it is possible to avoid a situation where the answer is synthesized with an unnatural low tone (high tone).

  In the above aspect, the speech synthesizer may change the pitch of the second section to a predetermined attribute when attempting to change the pitch to have a predetermined relationship with the pitch of the first section. Is defined, a pitch having a predetermined relationship may be further shifted to a pitch one octave higher or lower. An attribute is, for example, an attribute of a voice to be synthesized, and if it is determined to synthesize with a voice of a woman or a child (adult male), the pitch to be changed is a pitch having a predetermined relationship. By shifting to a pitch one octave above (below), it is possible to avoid a situation where the sound is synthesized with an unnatural bass (treble).

  In the above aspect, there are a first mode and a second mode as operation modes, and if the operation mode is the first mode, the speech synthesizer determines a pitch of the second section as a sound of the first section. If the operation mode is the second mode, the pitch of the second section is changed to a pitch that is in the relationship of the Kyowa interval except for 1 degree to the high. It is good also as a structure which changes and outputs so that it may become the pitch which has the relationship of a dissonance pitch with respect to the pitch of the said 1st area. In this aspect, if the operation mode is the second mode, answers having a dissonant pitch relationship are synthesized with speech, so that it is possible to give a sense of discomfort to the user who made the question. Conversely, by setting the second mode, the user can be alerted or intentionally disgusted.

The aspect of the present invention can be conceptualized as a program that causes a computer to function as the speech synthesizer as well as the speech synthesizer.
In the present invention, the pitch (frequency) of the question is set as the analysis target and the pitch of the answer is set as the control target, but the human voice has a certain frequency range as is clear from the above-described formant example. Therefore, it is inevitable that the analysis and control have a certain frequency range. In addition, as a matter of course, errors occur in analysis and control. For this reason, in this case, the pitch analysis and control are allowed not only to have the same numerical value of the pitch (frequency) but also to have a certain range.

It is a block diagram which shows the structure of the speech synthesizer which concerns on 1st Embodiment. It is a figure which shows the example of the sound formant in a dialog. It is a figure which shows the relationship between a pitch name, a frequency, etc. It is a flowchart which shows operation | movement of a speech synthesizer. It is a figure which shows the specific specific example of an ending. It is a figure which shows the example of the pitch shift with respect to an audio | voice sequence. It is a figure which shows the psychological influence which a synthetic speech gives with respect to the question by a user. It is a block diagram which shows the structure of the speech synthesizer which concerns on 2nd Embodiment. It is a figure which shows the example of the pitch conversion with respect to audio | voice waveform data. It is a figure which shows the principal part of the process in an application example (the 1). It is a figure which shows the principal part of the process in an application example (the 2). It is a figure which shows the principal part of the process in an application example (the 3). It is a figure which shows the operation | movement outline | summary of an application example (the 4).

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
First, the speech synthesizer according to the first embodiment will be described.
FIG. 1 is a diagram showing a configuration of a speech synthesizer 10 according to the first embodiment of the present invention.
In this figure, the speech synthesizer 10 is a terminal device such as a mobile phone having a CPU (Central Processing Unit), a speech input unit 102, and a speaker 142. In the speech synthesizer 10, the CPU executes an application program installed in advance, so that a plurality of functional blocks are constructed as follows.
Specifically, in the speech synthesizer 10, the utterance section detection unit 104, the pitch analysis unit 106, the language analysis unit 108, the answer creation unit 110, the speech synthesis unit 112, the language database 122, the answer database 124, the information acquisition unit 126, and An audio library 128 is constructed.
Although not particularly illustrated, the speech synthesizer 10 also includes a display unit, an operation input unit, and the like, so that the user can check the status of the device and input various operations to the device. Can be done. The speech synthesizer 10 is not limited to a terminal device such as a mobile phone, and may be a notebook or tablet personal computer.

Although not described in detail, the audio input unit 102 is a microphone that converts audio into an electric signal, an LPF (low-pass filter) that cuts a high-frequency component of the converted audio signal, and an audio signal that is cut from a high-frequency component. And an A / D converter that converts the signal into a digital signal.
The utterance section detection unit 104 processes the voice signal converted into the digital signal to detect the utterance (sound) section.

  The pitch analysis unit 106 frequency-analyzes the speech signal detected as an utterance section, obtains the pitch of a specific section (first section) among the first formants obtained by the analysis, and calculates the sound. Output pitch data indicating high. The first section is, for example, a question ending. In addition, the first formant is, for example, a component having the lowest frequency among a plurality of formants obtained when frequency analysis of speech is performed. In the example of FIG. Say. For frequency analysis, FFT (Fast Fourier Transform) or other known methods can be used. An example of a specific method for specifying the ending in the question will be described later.

  The language analysis unit 108 determines to which phoneme the speech signal detected as the speech section is close by referring to a phoneme model created in advance in the language database 122, and the meaning of the words defined by the speech signal Is analyzed (specified). As such a phoneme model, for example, a hidden Markov model can be used.

The answer creation unit 110 creates an answer corresponding to the meaning of the words analyzed by the language analysis unit 108 with reference to the answer database 124 and the information acquisition unit 126. For example, in response to the question “now what? (Now what time?)”, The speech synthesizer 10 obtains time information from a built-in real-time clock (not shown) and sends information other than the time information to the answer database. By acquiring from 124, it is possible to create an answer “I am now XX hour XX minutes”.
On the other hand, if the speech synthesizer 10 does not access the external server and acquire the weather information in response to the question “What is tomorrow? I cannot create an answer. As described above, when an answer cannot be created using only the answer database 124, the information acquisition unit 126 accesses the external server via the Internet and acquires information necessary for the answer. That is, the answer creating unit 110 is configured to obtain an answer to a question from the answer database 124 or an external server.
Note that in the present embodiment, the answer creating unit 110 outputs the answer as a phoneme sequence, which is a voice sequence that defines the pitches and pronunciation timings corresponding to each phoneme. If the speech synthesizer 112 synthesizes speech in accordance with a speech sequence in which the pitch and pronunciation timing are defined, the basic speech of the answer can be output. However, in this embodiment, the basic speech defined by the speech sequence is changed and output by the speech synthesizer 112.

  The voice synthesizer 112 has a predetermined relationship between the pitch of a specific section (second section) of the voice sequence created by the answer creator 110 and the pitch data supplied from the pitch analyzer 106. The voice is synthesized by changing to the pitch in the above and output as a voice signal. In the present embodiment, the second section is the ending of the answer, but is not limited to the ending as described later. In this embodiment, the pitch having a predetermined relationship with the pitch data is set to a pitch having a relationship of 5 degrees below, but as will be described later, a sound having a relationship other than 5 degrees is used. It can be high.

The speech synthesizer 112 uses speech unit data registered in the speech library 128 when synthesizing speech. The speech library 128 is a database of speech unit data defining waveforms of various speech units that are speech materials, such as a single phoneme or a transition part from a phoneme to a phoneme. Specifically, the speech synthesizer 112 combines the speech segment data of one sound per phoneme (phoneme) and corrects the connected portion to be continuous, and corrects the ending sound of the answer as described above. Change the height to generate an audio signal.
Note that the synthesized voice signal is converted into an analog signal by a D / A converter (not shown), then acoustically converted by the speaker 142 and output.

Next, the operation of the speech synthesizer 10 will be described. FIG. 4 is a flowchart showing the processing operation in the speech synthesizer 10.
First, when the user performs a predetermined operation, for example, when an icon or the like corresponding to the interactive process is selected on the main menu screen (not shown), the CPU starts an application program corresponding to the process. By executing this application program, the CPU constructs the functional block shown in FIG.

  First, in step Sa11, the user inputs a question to the voice input unit 102 by voice. Next, in step Sa12, the utterance section detecting unit 104 detects a section in which the volume of the voice, that is, a state in which the volume is equal to or lower than the threshold value continues for a predetermined period or more as a silence section, and detects other sections as a utterance section. Then, the speech signal of the speech section is supplied to each of the pitch analysis unit 106 and the language analysis unit 108.

  In step Sa13, the pitch analysis unit 106 analyzes the voice signal of the question in the detected utterance section, specifies the pitch of the first section (ending) in the question, and generates pitch data indicating the pitch. This is supplied to the speech synthesizer 112. Here, an example of a specific method for specifying the ending of the question in the pitch analysis unit 106 will be described.

When a dialogue is made in which a person who asks a question wants an answer to the question, it is considered that the volume corresponding to the ending of the question temporarily increases compared to the other parts. Therefore, the pitch of the first section (ending) by the pitch analysis unit 106 can be obtained as follows, for example.
First, the pitch analysis unit 106 divides the voice signal of the question detected as the speech section into a waveform by dividing it into a volume and a pitch (pitch). FIG. 5A is an example of a volume waveform in which the volume of an audio signal is represented on the vertical axis and the elapsed time is represented on the horizontal axis. FIG. 5B is a first waveform obtained by frequency analysis of the same audio signal. It is a pitch waveform in which the pitch of formant is represented on the vertical axis and the elapsed time is represented on the horizontal axis. The time axis of the volume waveform in (a) and the pitch waveform in (b) are common.
Secondly, the pitch analysis unit 106 identifies the timing of the last local maximum P1 in the volume waveform of (a).
Thirdly, the pitch analysis unit 106 determines that a predetermined time range (for example, 100 μsec to 300 μsec) including the timing of the specified maximum P1 before and after is the ending.
Fourth, the pitch analysis unit 106 outputs the average pitch of the section Q1 corresponding to the recognized ending in the pitch waveform of (b) as pitch data.
As described above, it is considered that erroneous detection of the ending of the question as a conversation can be reduced by specifying the final maximum P1 of the volume waveform in the utterance section as the timing corresponding to the ending of the question.
Here, in the volume waveform of (a), a predetermined time range including the timing of the last local maximum P1 before and after is recognized as the ending, but the predetermined time period having the maximum P1 timing as the start or end is determined. The time range may be recognized as the ending. Moreover, it is good also as a structure which outputs not the average pitch of the area Q1 corresponding to the recognized ending but the pitch of the start of the period Q1, the end, and the timing of local maximum P1 as pitch data.

  On the other hand, in step Sa <b> 14, the language analysis unit 108 analyzes the meaning of the words in the voice signal and supplies data indicating the meaning content to the answer creation unit 110. In step Sa15, the answer creating unit 110 creates an answer corresponding to the meaning of the analyzed word using the answer database 124, or obtains it from an external server via the information obtaining unit 126 as necessary. Then, a speech sequence based on the answer is created and supplied to the speech synthesis unit 112.

  FIG. 6A is an example of an answer voice (voice sequence) created in response to, for example, the question “What is tomorrow?”. In the example of this figure, a note is assigned to each sound of the answer “Hare is”, and the pitch and pronunciation timing of each word (phoneme) of the basic speech based on the speech sequence are shown. In this example, for simplicity of explanation, one note is assigned to one note (phoneme), but a plurality of notes may be assigned to one note such as a slur or a tie.

Next, in step Sa16, the speech synthesizer 112 identifies the ending pitch (initial pitch) in the speech sequence from the speech sequence supplied from the answer creation unit 110.
Subsequently, in step Sa17, the speech synthesizer 112 has a relationship in which the initial pitch of the ending defined by the speech sequence is 5 degrees below the pitch indicated by the pitch data from the pitch analyzer 106. As described above, the pitch defined by the voice sequence is changed.
For example, as shown in (b) of FIG. 6, the pitch of the section “ha” at the end of the word “A” indicated by the symbol “A” is “So” according to the pitch data. The speech synthesizer 112 has a pitch that is 5 degrees below the “Seo” in the “S” section of the ending “S” that is indicated by the symbol B in the answer “It is a spread”. The pitch of the entire audio sequence is changed so that it becomes a certain “do”.
In step Sa18, the speech synthesizer 112 synthesizes and outputs the speech of the modified speech sequence. When the answer voice is output, the CPU ends the execution of the application program and returns to the menu screen, although not particularly illustrated.

FIG. 7 is a diagram for explaining an impression given to the user by the speech synthesizer 10 according to the present embodiment. As shown in (a) of the figure, the user W inputs the question “What is tomorrow?” To the speech synthesizer 10 which is a terminal device. If the pitch of “ha” corresponding to the ending of the question at this time is “so”, in the embodiment, as shown in FIG. The pitch is shifted so that the pitch of “su” corresponding to is “do”, and speech synthesis is performed. For this reason, it is possible to give a good impression as if the user W is interacting without giving the user W an unnatural feeling.
On the other hand, as shown in (c) of the figure, when the speech synthesis is performed without shifting the pitch of the speech sequence of “It is a spread” (see FIG. 6 (a)), the sound of “su” corresponding to the end of the sound. High is output with "Fa". In this case, the pitch “Fa” has a dissonant pitch relationship with the “ha” pitch “So” corresponding to the ending of the question “What is the tomorrow?” That is, referring to FIG. 3, the frequency of “So” (396.0 Hz) is 9/8 relative to the frequency of “Fa” (352.0 Hz). For this reason, it does not give the user W an unnatural feeling, but rather gives a bad impression like disgust. However, as will be described later, the voice synthesizer 10 may be configured to positively give such a bad impression to the user.

Second Embodiment
Next, a second embodiment will be described.
FIG. 8 is a block diagram showing the configuration of the speech synthesizer 10 according to the second embodiment.
In the first embodiment, the answer creation unit 110 outputs a voice sequence in which a pitch is assigned to each note as an answer to the question. In the second embodiment, the answer voice output unit 113 The answer to the question is acquired, and the voice waveform data of the answer is output.
The acquired answers include those created by the answer voice output unit 113, those obtained from an external server, and those selected from a plurality of answers prepared in advance. The voice waveform data is, for example, data in the wav format, and a pitch is not assigned to each sound as in the above-described voice sequence. Therefore, simply reproducing such voice waveform data provides a mechanical feeling as shown in FIG.

  Now, when the speech waveform data is reproduced, the post-processing unit 114 changes the ending of the answer to the ending of the question so that the ending of the answer has a relationship of the Kyowa interval. Specifically, the post-processing unit 114 analyzes the pitch of the ending when the speech waveform data is simply reproduced, and the analyzed pitch is indicated by the pitch data from the pitch analysis unit 106. For example, the voice waveform data output from the answer voice output unit 113 is pitch-converted (pitch-converted) so that the relation is 5 degrees below. That is, in the second embodiment, the post-processing unit 114 sets the pitch of the ending of the acquired answer to a pitch that is 5 degrees below which is an example of the Kyowa pitch with respect to the pitch of the ending of the question. Change and output.

  The result of this conversion is almost the same as the pitch shift shown in FIG. 6B, as shown in FIG. 9B. According to this structure, when the answer to a question does not need to be specific, for example, when answering a simple answer such as “Yes” or “No” or a question like “Yes” The answer voice output unit 113 may be configured to select and output one of the voice waveform data in response to the question from the plurality of voice waveform data stored in advance.

<Applications / Modifications>
The present invention is not limited to the first embodiment and the second embodiment described above, and various applications and modifications as described below, for example, are possible. In addition, one or more arbitrarily selected aspects of application / deformation described below can be appropriately combined.

<Voice input part>
In the embodiment, the voice input unit 102 is configured to input a user's voice (speech) using a microphone and convert the voice signal into a voice signal. However, the voice input unit 102 is not limited to this configuration, and the voice signal processed by another processing unit or A configuration may be adopted in which an audio signal supplied (or transferred) from another device is input. In other words, the voice input unit 102 only needs to be configured to input a speech by a voice signal in some form.

<End of answer, beginning of answer>
In the first and second embodiments, the pitch of the ending of the answer is controlled in response to the pitch of the ending of the question. However, depending on the language, dialect, wording, etc., the portion other than the ending of the answer For example, the beginning of a word may be characteristic. In such a case, the person who asked the question unconsciously compares the pitch of the ending of the question with the pitch of the characteristic beginning of the answer when there is an answer to the question. To determine the impression of the answer. Therefore, in this case, the pitch of the beginning of the answer may be controlled corresponding to the pitch of the ending of the question. According to this configuration, when the head of the answer is characteristic, it is possible to give a psychological impression to the user who receives the answer.

  The same applies to the question, not limited to the end of the word, but may be determined by the beginning of the word. In addition, the question and answer are not limited to the beginning and end of the word, but may be determined based on an average pitch or determined based on the pitch of the most pronounced portion. For this reason, it can be said that the 1st area of a question and the 2nd area of an answer are not necessarily restricted to an initial or ending.

<Pitch relationship>
In the embodiment described above, the voice synthesis is controlled such that the pitch of the ending of the answer is 5 degrees lower than the ending of the question. However, the control is performed in a relationship of Kyowa intervals other than 5 degrees below. It may be a configuration. For example, as described above, it may be complete 8 degrees, complete 5 degrees, complete 4 degrees, long / short 3 degrees, and long / short 6 degrees.
In addition, there is a case where a relationship of a pitch that gives a good (or bad) impression is empirically recognized even if it is not a relationship of the Kyowa pitch, so that the pitch of the answer is controlled according to the relationship of the pitch. good. However, even in this case, if the pitch between the pitch of the question ending and the pitch of the answer ending is too far apart, the answer to the question tends to be unnatural. It is desirable that the pitch of the answer is in the range of one octave above and below.

<Pitch shift of answer>
By the way, in the configuration for controlling the pitch of the ending of the answer specified by the voice sequence and the voice waveform data so as to have a predetermined relationship with the pitch of the ending of the question, the details of the embodiment are described. Thus, for example, in a configuration in which the pitch is changed to be 5 degrees below, if the pitch 5 degrees below is too low, the answer may be synthesized with an unnatural bass. Next, application examples (No. 1 and No. 2) for avoiding such a case will be described.

FIG. 10 is a diagram illustrating a main part of processing in the application example (part 1). Here, the main part of the processing means processing executed in “determination of answer pitch” in step Sa17 in FIG. That is, in the application example (No. 1), the processing shown in FIG. 10 is executed in step Sa17 shown in FIG. 4, and details are as follows.
First, the speech synthesizer 112 obtains and temporarily determines a pitch that is, for example, 5 degrees below the pitch indicated by the pitch data from the pitch analyzer 106 (step Sb171).
Next, the speech synthesis unit 112 determines whether or not the temporarily determined pitch is lower than a predetermined threshold pitch (step Sb172). Note that the threshold pitch is set to a pitch corresponding to the lower limit frequency for speech synthesis, or a pitch that gives an unnatural feeling if it is lower than this.

If the tentatively determined pitch, that is, the pitch 5 degrees below the ending pitch in the question is lower than the threshold pitch (if the determination result in step Sb172 is “Yes”), the speech synthesis unit 112 The temporarily determined pitch is shifted to a pitch one octave higher (step Sb173).
On the other hand, if the obtained pitch is equal to or higher than the threshold pitch (if the determination result of step Sb172 is “No”), the process of step Sb173 is skipped.
Then, the speech synthesizer 112 finally determines the target ending pitch as the following pitch when shifting the pitch of the answer (step Sb174). That is, if the tentatively determined pitch is lower than the threshold pitch, the voice synthesizer 112 changes the tentatively determined pitch to one pitch above, and the tentatively determined pitch is equal to or higher than the threshold pitch. If so, the target pitches are finally determined without changing the temporarily determined pitches.
The processing procedure returns to step Sa18 in FIG. 4 after step Sb174. Therefore, the voice synthesizer 112 synthesizes and outputs the voice of the voice sequence changed to the final pitch.

According to this application example (No. 1), if the pitch to be changed is lower than the threshold pitch, the pitch is shifted so as to be one octave higher than the pitch. It is possible to avoid the point that the answer is synthesized by voice.
In this example, the pitch of the ending of the answer is shifted to a pitch one octave higher, but may be shifted to a pitch one octave lower. Specifically, since the pitch of the ending of the question issued by the user is high, if the pitch 5 degrees below the pitch is too high, the answer is synthesized with an unnatural high tone. . In order to avoid this, if the pitch (temporarily determined pitch) that is 5 degrees below the pitch indicated by the pitch data is higher than the threshold pitch, the pitch of the ending of the answer is set. The pitch may be shifted to a pitch one octave lower than the temporarily determined pitch.

  In addition, when voice synthesis is performed, it may be possible to output a voice of a virtual character in which sex or age (child / adult) is determined. When a female or child character is specified as in this case, if the pitch is lowered to 5 degrees below the ending of the question, the answer is synthesized with a bass sound that is not suitable for the character. Therefore, similarly, it may be configured to shift so that the pitch becomes one octave higher.

  FIG. 11 is a diagram showing a main part of processing in such an application example (part 2), and shows processing executed in “determination of answer pitch” in step Sa17 in FIG. Description will be made centering on differences from FIG. 10. In step Sb171, the speech synthesizer 112 obtains a pitch that is 5 degrees below the pitch indicated by the pitch data from the pitch analyzer 106. Then, it is determined whether or not a woman or a child is designated as an attribute that defines the character (step Sc172).

If female or child is specified as the attribute (if the determination result in step Sc172 is “Yes”), the speech synthesizer 112 shifts the temporarily determined pitch to a pitch one octave higher (step Sb173) On the other hand, if female or child is not specified as the attribute, for example, if male or adult is specified (if the determination result of step Sc172 is “No”), the process of step Sb173 is skipped. Is done. The subsequent steps are the same as in the application example (No. 1).
According to this application example (No. 2), if the setting is made to answer in the voice of a woman or child, the pitch is shifted so that the pitch is one octave higher than the temporarily determined pitch. It can be avoided that the answer is synthesized with an unnatural low tone.
In this example, if female or child is specified as an attribute, the pitch is shifted to one octave above. However, for example, if an adult male is specified as an attribute, the character corresponding to the attribute is not recognized. In order to avoid that the answer is synthesized with high-pitched sounds, the pitch may be shifted to a pitch one octave below.

<Dissonance>
In the above-described embodiment, the voice synthesis is controlled so that the pitch of the answer ending is in the relationship of the consonant pitch with respect to the ending of the question. May be controlled. In addition, if the answers are synthesized with pitches that have a dissonant pitch relationship, the user who asked the question will be given an unnatural feeling, a bad impression, a harsh feeling, etc., and a smooth dialogue will not be established There are also concerns, but there is a view that this feeling is good for stress relief.
Therefore, as an operation mode, a mode (first mode) for which a response such as a good impression is desired and a mode (second mode) for which a response such as a bad impression is desired are prepared, and speech synthesis is controlled according to any mode. It is good also as composition to do.

  FIG. 12 is a diagram showing a main part of processing in such an application example (part 3), and shows processing executed in “answer pitch determination” in step Sa17 in FIG. The description will focus on points different from FIG. 10. The speech synthesizer 112 determines whether or not the first mode is set as the operation mode (step Sd172).

If the first mode is set as the operation mode (if the determination result of step Sd172 is “Yes”), the speech synthesizer 112 changes the pitch of the ending of the answer to the pitch of the ending of the question, for example. On the other hand, the pitch is determined so as to be a pitch having a relation of Kyowa pitch (step Sd173A). On the other hand, if the second mode is set as the operation mode (if the determination result in step Sd172 is “No”), the speech synthesizer 112 sets the pitch of the answer ending to the pitch of the question ending. On the other hand, the pitch is determined to be a pitch having a dissonant pitch relationship (step Sd173B). The subsequent processes are the same as those of the application example (part 1) and the application example (part 2).
Therefore, according to this application example (No. 3), if the first mode is set, the answer is synthesized with a pitch having a relationship of the Kyowa interval with the pitch of the question, while the second mode Is set, the answer is synthesized with a pitch that is in a dissonant pitch with respect to the pitch of the question, so that the user can use the operation mode appropriately.

  The application example (part 1), the application example (part 2), and the application example (part 3) have been described as examples using the voice sequence as in the first embodiment, but the voice as in the second embodiment. Of course, waveform data may be used.

<Voice / Answer>
In the embodiment, the answers are synthesized by voice synthesis using human voices. However, in addition to voices by humans, voice synthesis may be performed by animal calls. That is, the voice here is not limited to a human voice, but is a concept that includes an animal call. Next, an application example (part 4) in which an answer is synthesized with an animal call will be described.

  FIG. 13 is a diagram showing an outline of the operation of this application example (No. 4). In the case of synthesizing an answer with the sound of an animal call, the processing is only to make the ending of the cry to a predetermined pitch with respect to the pitch of the ending of the question. For this reason, the process of analyzing the meaning of the question, obtaining information corresponding to the analyzed meaning, and creating an answer based on the information becomes unnecessary.

  As shown in (a) of the figure, when the user W issues a question “I'm happy” and inputs it to the speech synthesizer 10, the speech synthesizer 10 will answer “Ne” corresponding to the ending of the question. ”Is analyzed, and if the pitch is“ Seo ”, for example, the voice waveform data of the dog call“ One ”is post-processed, and the“ N ”sound corresponding to the ending of“ One ” The pitch is changed to be “do”, which is a pitch 5 degrees below which is an example of the Kyowa interval with respect to the pitch of the ending of the question.

  When the answer is synthesized with the sound of an animal, the information desired by the user cannot be obtained with the answer. In other words, even if the user asks "What is Asuno Tenki?", The user cannot obtain tomorrow's weather information. However, when the user issues a question, if the voice is synthesized such that the ending of the squeak is 5 degrees below the pitch of the ending of the question, the squeal is comfortable, It is the same as the case of synthesizing an answer with a human voice in terms of giving a good impression of relief. Therefore, even when synthesizing animal calls, it can be expected to give the user a kind of healing effect as if they are communicating with the virtual animal that makes the call. .

In addition, a display unit is provided in the speech synthesizer 10 to display a virtual animal as shown in (b) of the figure, and for the animal, the tail is shaken in synchronization with the speech synthesis. It is good also as a structure displayed by animation, such as tilting. With such a configuration, the healing effect can be further enhanced.
Moreover, when the animal which synthesize | combines a cry is made into a dog, for example, it is good also as a structure which can select dog breeds (Chihuahua, Pomeranian, a golden retriever, etc.).
The speech synthesizer 10 that synthesizes an answer with the sound of an animal is not limited to a terminal device, and may be applied to a pet robot imitating the animal, a stuffed animal, or the like.

<Others>
In the embodiment, the language analysis unit 108, the language database 122, and the answer database 124, which are configured to acquire an answer to a question, are provided on the side of the speech synthesizer 10, but the processing load is heavy in a terminal device or the like. In view of the above, the storage capacity is limited, and the like may be provided on the external server side. That is, it is sufficient that the answer creating unit 110 (answer voice output unit 113) in the speech synthesizer 10 obtains an answer to the question in some form and outputs a voice sequence (speech waveform data) of the answer. It does not matter whether the answer is created on the side of the speech synthesizer 10 or on the side of a configuration other than the speech synthesizer 10 (for example, an external server).
Note that the information acquisition unit 126 is unnecessary if the speech synthesizer 10 can be used to create an answer to a question without accessing an external server or the like.

DESCRIPTION OF SYMBOLS 102 ... Voice input part, 104 ... Speech area detection part, 106 ... Pitch analysis part, 108 ... Language analysis part, 110 ... Answer preparation part, 112 ... Speech synthesis part, 126 ... Information acquisition part.

Claims (7)

A voice input unit for inputting questions by voice signals;
Among the questions, a pitch analysis unit that analyzes the pitch of a specific first section;
An acquisition unit for acquiring an answer to the question;
Among the obtained answers, a speech synthesizer that changes and outputs the pitch of a specific second section so that the pitch has a predetermined relationship with the pitch of the first section;
Comprising
The first interval is the ending of the question;
The second section, Ri prefix or suffix der of the answer,
The predetermined relationship is a relationship of Kyowa intervals excluding perfect 1 degree.
A speech synthesizer characterized by the above. The speech synthesizer
The pitch of the second section is changed so as to have a pitch relationship within a range of one octave above and below, except for the same pitch as the pitch of the first section, and output. The speech synthesizer according to 1 . The speech synthesizer
The pitch of the second section, wherein the first section of the pitch, claim and outputs modified as a pitch in relation Kyowa interval under 5 ° 1 or The speech synthesizer according to 2 . The speech synthesizer
When changing the pitch of the second section to be a pitch having a predetermined relationship with the pitch of the first section,
If the pitch to be changed is lower than a predetermined threshold pitch, the pitch to be changed is further shifted to a pitch one octave higher, or
If the pitch to be changed is higher than a predetermined threshold pitch, the pitch to be changed is further shifted to a pitch one octave below.
The speech synthesizer according to claim 1 or 2 . The speech synthesizer
If the pitch of the second section is to be changed to be a pitch having a predetermined relationship with the pitch of the first section, if a predetermined attribute is defined, the predetermined relationship speech synthesis apparatus according to claim 1 or 2, characterized in that shifting to the pitch the further one octave higher or lower pitch in. There are a first mode and a second mode as operation modes,
The speech synthesizer
If the operation mode is the first mode, the pitch of the second section is set to a pitch that is in a relationship of Kyowa intervals except for the perfect pitch with respect to the pitch of the first section. Change and output,
If the operation mode is the second mode, the pitch of the second section is changed and output so that the pitch is in a dissonant pitch relative to the pitch of the first section.
The speech synthesizer according to claim 1. Computer
Get answers to questions from input audio signals,
Among the questions, analyze the pitch of a specific first section,
Among the obtained answers, the pitch of the specific second section is changed and output so that the pitch is in a predetermined relationship with the pitch of the first section,
The first interval is the ending of the question;
The second section, Ri prefix or suffix der of the answer,
The predetermined relationship is a relationship of Kyowa intervals excluding perfect 1 degree.
A speech synthesis method characterized by the above.

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