JP5151762B2 - Speech enhancement device, portable terminal, speech enhancement method, and speech enhancement program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voice emphasis apparatus, mobile terminal, voice emphasis method and voice emphasis program in which a received voice is made clearer and easy to hear by emphasizing the voice while considering properties of both surrounding noises and the received voice. <P>SOLUTION: A voice emphasis apparatus includes: a noise level calculating means for estimating properties of noises around a mobile terminal user; an emphasis amount control means for setting a parameter upon receipt of a selection input from the user to control an emphasis amount in accordance with the setting; and an emphasis property calculating means for calculating an emphasis property for a received voice signal on the basis of properties of a received signal, the calculated properties of the surrounding noises, and the set parameter. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a speech enhancement device, a portable terminal, a speech enhancement method, and a speech enhancement program that take into account the characteristics of both ambient noise and received speech.

  In recent years, mobile phones have become widespread and are used in various places. Mobile phones are often used not only in quiet places, but also in noisy environments such as airport lobbies and station platforms.

  For this reason, there is a problem that the received sound is difficult to hear due to the ambient noise of the user. The simplest method for making it easier for the listener to hear the voice of the sender in a noisy environment is to increase the volume according to the noise level. However, if the volume is increased too much, the input to the speaker of the mobile phone becomes excessive and the sound is distorted, which may deteriorate the sound quality.

  As a method of preventing deterioration of sound quality and improving speech intelligibility, speech is input to an equalizer, the characteristic parameters of the equalizer are controlled according to the ambient noise level, and the sound that has been equalized by the characteristic parameters is speakered. Output from the other, and formant enhancement according to ambient noise to improve the speech clarity.

  However, considering the ambient noise level, the speech formant is adaptively changed to enhance the received speech, but the received speech enhancement level cannot be selected. In the quiet environment, there is no effect of improving the clarity of the received voice, and since the user's auditory characteristics are not considered, the clarity of the user's hearing cannot be improved. It was.

  In addition, mobile phones such as WCDMA and GSM are often used not only in quiet places but also in noisy environments such as intersections and station platforms. For this reason, there is a problem that it is difficult to hear the received voice output from the receiving speaker due to the ambient noise on the user side of the mobile phone.

  Furthermore, the easiest way to make it easier for the user to hear the received voice output from the receiving speaker in a noisy environment is to increase the volume of the receiving speaker, but if the volume is too high, the receiving speaker Too much input may cause distortion of the sound, making it difficult to hear the sound, and increasing the burden on the user's ear, which may adversely affect hearing through long-time calls.

  Here, as a method of preventing sound quality degradation and improving speech intelligibility, the characteristic parameter of the equalizer is controlled according to the ambient noise level, and the sound processed by the characteristic parameter is output from the speaker. There is something to do.

  For example, Patent Literature 1 analyzes a signal collected by a microphone of a portable terminal on the receiver side, and determines whether it is a background noise section or a voice section. In the case of the noise section, the noise level is estimated, and a control signal for controlling the characteristic of the equalizer is generated based on the estimated noise level. Based on the control signal, the equalizer selects a characteristic parameter for determining the characteristic of the equalizer from the table. The sound (decoded sound) is subjected to an equalizer process by an equalizer constituted by the selected characteristic parameter, subjected to D / A conversion, and then output from a speaker.

In Patent Documents 2 and 3, there is a conventional technique for increasing speech clarity by selectively amplifying a speech formant and combining enhanced formants.
JP-A-9-135194 Japanese Patent No. 3151459 JP 2004-289614 A

  However, although Patent Document 1 adaptively changes the equalizer process for speech in consideration of the ambient noise level, the feature of speech is not considered. For this reason, the problem that the effect of improving the intelligibility is not sufficient depending on the type of sound remains.

  In Patent Documents 2 and 3, the received speech is emphasized by adaptively changing the speech formant in consideration of the ambient noise level, but the enhancement level of the received speech cannot be selected. If it is large, sufficient clarity cannot be ensured. In a quiet environment, there is no effect of improving the clarity of the received voice. Since the user's auditory characteristics are not considered, the clarity of the user's hearing is improved. The big problem that it is not made remains.

  Therefore, the present invention can provide a speech enhancement device, a portable terminal, a speech enhancement method, and a speech enhancement program that have a reception clarity improving function and emphasize speech in consideration of characteristics of both ambient noise and received speech. To do.

In order to achieve the above object, a first speech enhancement apparatus according to the present invention receives a noise level calculation means for estimating a characteristic of ambient noise of a mobile terminal user and a selection input of the enhancement amount of the user. Emphasis amount control means for controlling the emphasis amount according to the setting, received signal characteristics, calculated ambient noise characteristics, and received voice signal enhancement characteristics based on the set parameters has a highlight characteristic calculation means for calculating, and speech enhancement means outputting to emphasize the reception voice signal based on the emphasis characteristic, the speech enhancement means detects the level of each band of the received voice level A band-pass filter having a center frequency in consideration of a voice formant, which controls voice enhancement based on the detected level for each band, and has a center frequency in consideration of the voice formant. Divide the band, detect the level of each band by the level detection means, calculate the emphasis characteristics, adjust the amplitude of each band, calculate the reference level from the signal level detected by the level detection means, The amount of enhancement is calculated based on the signal level of each band and the noise level calculated by the noise level calculation means, and the amount of enhancement is calculated based on the amount of enhancement obtained by adding the parameters output from the enhancement amount control means. The gain is calculated, and the sum of the enhancement amount calculated by the enhancement characteristic calculation means and the enhancement amount control parameter is set so that the maximum value of the enhancement amount does not exceed .

  A first portable terminal according to the present invention includes the speech enhancement apparatus according to the present invention.

According to a first speech enhancement method of the present invention, a parameter is set in response to a noise level calculation step for estimating a characteristic of ambient noise of a mobile terminal user and a selection input of a user's enhancement amount , and according to the setting An enhancement amount control step for controlling the enhancement amount, an enhancement characteristic calculation step for calculating an enhancement characteristic of the received speech signal based on the characteristics of the received signal, the calculated characteristics of the ambient noise, and the set parameters. A speech enhancement step of enhancing and outputting the received speech signal based on the enhancement characteristics, and in the speech enhancement step, level detection is performed to detect a level for each band of the received speech, and the detected bandwidth Based on the level of each, the voice emphasis is controlled, the band is divided by a bandpass filter having a center frequency considering the voice formant, and the level detection process detects the level of each band. Calculate the emphasis characteristics, adjust the amplitude of each band, calculate the reference level from the signal level detected in the level detection step, and calculate the signal level of each band after division and the noise level calculation step The enhancement amount is calculated based on the noise level calculated, the gain of each band is calculated based on the enhancement amount obtained by adding the parameters output in the enhancement amount control step, and the enhancement amount calculated in the enhancement characteristic calculation step And the total of the enhancement amounts for the enhancement amount control parameter are set so that the maximum value of the enhancement amount does not exceed .

A first speech enhancement program according to the present invention receives a noise level calculation process for estimating a characteristic of ambient noise of a mobile terminal user and a selection input of a user's enhancement amount , sets parameters, and according to the settings Enhancement amount control processing for controlling the enhancement amount, enhancement characteristics calculation processing for calculating enhancement characteristics of the received speech signal based on the characteristics of the received signal, the calculated characteristics of the ambient noise, and the set parameters A speech enhancement process for enhancing and outputting the received speech signal based on the enhancement characteristics, and the speech enhancement process is performed by performing level detection for detecting a level for each band of the received speech. Based on the level for each band, voice emphasis is controlled, and the band is divided by a bandpass filter having a center frequency considering the voice formant. Perform level detection of each band, calculate enhancement characteristics, perform amplitude adjustment of each band, calculate a reference level from the signal level detected in the level detection process, the signal level of each band after division, and The enhancement amount is calculated based on the noise level calculated in the noise level calculation processing, the gain of each band is calculated based on the enhancement amount obtained by adding the parameters output in the enhancement amount control processing, and the enhancement characteristic calculation The sum of the enhancement amount calculated by the process and the enhancement amount for the enhancement amount control parameter is set so that the maximum value of the enhancement amount does not exceed .

  The present invention provides a speech enhancement device, a portable terminal, a speech enhancement method, and a speech enhancement program that make a received speech clearer and easier to hear by enhancing the speech in consideration of the characteristics of both ambient noise and received speech. Is possible.

  The present invention achieves the following.

  The present invention is a portable terminal having a function for improving the intelligibility of received speech, and enhances the speech in consideration of the characteristics of both ambient noise and received speech, thereby making the received speech clearer and easier to hear. There is an effect of improving speech intelligibility by emphasizing formants according to noise and improving speech intelligibility by adjusting the reception volume when ambient noise is large, and selecting the effect of improving intelligibility by user setting This makes it possible to improve the intelligibility of the received voice according to the user's hearing even in a quiet environment with little ambient noise.

  In addition, as a parameter of the received sound intelligibility improvement function, there is a parameter that is considered so as to correct the deterioration of the ease of hearing of auditory treble due to aging. The intelligibility improvement process can correct deterioration of the ease of hearing of high-pitched sounds, and can improve the ease of listening to the received sound.

  The present invention that realizes the above has, for example, a reception clarity improving function, and includes a speech enhancement unit, enhancement amount control unit, enhancement characteristic calculation unit, and noise level calculation unit in the DSP, and the mobile terminal is in a call state. Then, the user selects the effect of the received speech intelligibility improving function, and the parameter is input to the enhancement amount control unit. The received voice is input to the voice enhancement unit and the enhancement characteristic calculation unit. On the other hand, the ambient noise of the mobile terminal user is picked up by the microphone, the noise level calculation unit estimates the noise characteristics, and the estimated characteristics are given to the enhancement characteristic calculation unit. The enhancement characteristic calculation unit calculates the reception voice enhancement characteristic in consideration of parameters determined by the received voice characteristic and noise characteristic and the user's effect selection, and outputs the received voice enhancement characteristic to the voice enhancement unit. Is processed and output from the speaker to the user.

  The first feature described above is that the received voice enhancement amount in the enhancement characteristic calculation unit can be controlled by the parameter of the enhancement amount control unit in the DSP. The effect of improving clarity can be adjusted.

  The second feature described above is that, by selecting the effect of improving the intelligibility of the received voice by the user's operation, the received voice can be easily heard even in a quiet environment with little ambient noise.

  The third feature described above has a parameter that is considered as a parameter of the reception sound intelligibility improvement function so as to correct deterioration of the hearing easiness of the auditory treble due to aging. In addition, it is possible to correct deterioration in the ease of hearing of high-pitched sounds by the clarity-increasing process of the reception clarity improving function, and to improve the ease of hearing of the received sound.

Hereinafter, embodiments of the present invention will be described.
The embodiments described below are suitable or best configurations and processes for solving the problems of the present invention. However, the present invention is not limited to this, and the configuration and processing can be modified and changed within a range that can be easily conceived by those skilled in the art.

(Embodiment 1)
In the present embodiment, first, the configuration of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram showing an example of the configuration of a portable terminal with a voice enhancement function according to the present invention.

  As shown in FIG. 1, the mobile terminal includes a CPU 1, a wireless unit 2, a display unit 3, an operation unit 4, a voice decoder 5, a digital signal processor (hereinafter referred to as DSP) 20, a microphone 9, a microphone amplifier 10, A / D converter 11, speech encoder 12, D / A converter 6, speaker amplifier 7, speaker 8, and battery, power supply / charge circuit, memory, antenna, etc., not shown.

  The CPU 1 is a central control unit that performs various arithmetic processing related to a call and processing related to voice correction on the mobile terminal. The wireless unit 2 has a function of modulating / demodulating a signal according to a predetermined communication protocol, and performs a process of demodulating a wireless signal received via an antenna. The display unit 3 is configured by, for example, an LCD (Liquid Crystal Display) and displays information necessary for operation.

  The operation unit 4 includes key buttons for inputting telephone numbers and the like, and operation buttons for performing operations such as music playback, and has a function of outputting an input signal corresponding to a user operation to the CPU 1. The speech decoder 5 decodes the encoded received signal into a signal having an amplitude value sampled at a predetermined sampling frequency in the time axis region, and outputs the received speech signal to the speech enhancement unit 21 in the DSP 20.

  The D / A converter 6 converts the digital signal output from the audio decoder 5 and processed by the DSP 20 into an analog signal and outputs the analog signal to the speaker amplifier 7. The speaker amplifier 7 amplifies the analog signal from the D / A converter 6 and outputs it as a received voice from the speaker 8.

  The microphone 9 is a device that collects call voice and ambient noise and converts it into an electrical signal. The microphone amplifier 10 amplifies the output signal of the microphone 9, and the A / D converter 11 is amplified by the microphone amplifier 10. The analog signal is converted into a digital signal and output to the speech encoder 12 and the DSP 20. The voice encoder 12 encodes the output signal of the microphone 9 that has been A / D converted, and outputs the encoded signal to the radio unit 2.

  Next, the configuration of the DSP 20 will be described.

  The DSP 20 includes a voice enhancement unit 21, an enhancement amount control unit 22, an enhancement characteristic calculation unit 23, and a noise level calculation unit 24. The noise level calculation unit 24 has a function of calculating the level of ambient noise from the digital signal picked up by the microphone 9, amplified by the microphone amplifier 10, and converted by the A / D converter 11, and is output to the enhancement characteristic calculation unit 23. .

  The enhancement amount control unit 22 is a control unit for performing enhancement amount increase / decrease control of the enhancement characteristic calculation unit 23 based on a parameter determined by the received speech enhancement level setting selected by the user. Based on the noise level signal calculated by the noise level calculation unit 24, the output signal from the speech encoder 5, and the parameter from the enhancement amount control unit 22, the enhancement characteristic calculation unit 23 enhances the received speech signal by the speech enhancement unit 21. The emphasis characteristic for calculating is calculated, and a signal is output to the voice emphasizing unit 21. The voice enhancement unit 21 processes the received voice signal based on the enhancement characteristic calculated by the enhancement characteristic calculation unit 23 and outputs the voice signal after the signal processing to the A / D converter 6.

  Next, the configuration of the voice enhancement unit 21 will be described with reference to FIG.

  The speech enhancement unit 21 includes a bandpass filter 211, a level detection unit 212, an enhancement control unit 213, and a band signal combining unit 214.

  The band pass filter 211 is a filter for dividing the audio signal into bands, and is divided into n center frequencies. The level detection unit 212 detects the level of the divided band signal and outputs the level of each band to the enhancement characteristic calculation part 22.

  The emphasis control unit 213 is composed of a voltage control amplifier (VCA), and performs gain control of the amplifier based on the gain of each band calculated by the emphasis characteristic calculation unit 23 to amplify each band signal.

  The band signal combiner 214 functions to combine the amplified signals. That is, the output signal of the band signal combining unit 214 is the signal amplified by the emphasis control unit 213 for each band divided by the band pass filter 211 with respect to the audio signal before the emphasis processing input to the band pass filter 211. It is a combined signal (enhanced audio signal).

  The operation of the embodiment of the present invention will be described. First, the basic concept of the relationship between speech formants and speech intelligibility will be described.

  Human speech is generated by producing sounds in the vocal tract, which resonate these sounds at different frequencies. Vowels are generated by vocal cord vibration. The sound generated by the vibration of the vocal cords is composed of harmonic components that are continuous with the fundamental frequency. The amplitude of the harmonics attenuates with increasing frequency at a rate of about 12 decibels per octave.

  The fundamental frequency and its overtones have a feature that has a peak at a frequency corresponding to a specific resonance of the vocal tract by passing through the vocal tract including a cavity in the throat and mouth where the resonance occurs, and this peak is called a formant.

  FIG. 3 is a graph showing the amplitude with respect to the frequency of speech (for example, vowels), and the amplitude decreases as the second form, third order, and higher order with respect to the first formant.

  FIG. 4 explains the principle of frequency spectrum enhancement (formant enhancement). The broken line graph represents the characteristic before enhancement, the solid line graph represents the characteristic after enhancement, and the characteristic after enhancement represents a state in which the levels of the second and third formants are raised. It is generally known to enhance the intelligibility of speech without increasing the average volume by emphasizing higher-order formants.

  In the present invention, this feature is used to emphasize high-order formants in accordance with the ambient noise level of the mobile terminal user, and when the ambient noise level is high, the received volume is also increased to make the received voice easier to hear. It improves the thickness.

  Here, auditory deterioration due to aging will be described. In general, the auditory sensation of humans increases with age as the level of hearing loss increases (below, the minimum audible limit) due to hardening of the transmission system such as the eardrum, ossicular joint, and muscle, and loss of cells at the base of the cochlea. .

  FIG. 5 shows an average increase in the minimum audible limit due to age with reference to the minimum audible limit around 20 years old. According to FIG. 5, it is difficult to hear high-frequency (2 kHz or higher) sound that has a great influence on the intelligibility of the received voice due to an increase in age.

  That is, when the age is over 40 years old, it becomes difficult to hear a high tone, so that the clarity of the received voice is lowered. In order to make it easy to hear the received voice, it is important to compensate for the sensitivity deterioration of the high-frequency hearing. The present invention is intended to improve the clarity of the received voice by paying attention to the above-mentioned deterioration of the high frequency range of hearing due to aging.

  Next, the operation of the present invention will be described with reference to FIG.

  FIG. 6 is a flowchart for explaining the basic operation of the received call clarity improving function which is a function of the present invention.

  When the mobile terminal changes from the standby state (step S601) to the telephone conversation state (step S602), a setting screen for the clarity improving function is displayed on the display unit 3, and the user sets the setting of the clarity improving function to “OFF” or “normal”. , “Strong” is selected (step S603), and the function key of the operation unit 4 is pressed.

  Subsequently, the setting of the intelligibility improvement function is determined (step S604). If it is determined that the intelligibility improvement function is set to “normal” or “strong”, a parameter corresponding to the selected setting value is set. Is called and sent to the emphasis amount control unit 22 (step S605).

  The ambient noise picked up by the microphone 9 (step S606) is output as an analog signal, amplified by the microphone amplifier 10, amplified by the A / D converter 11 from an analog signal to a digital signal, and sent to the speech encoder 12 and the DSP 20. It is input as a transmission signal.

  For the transmission signal input to the DSP 20, the noise level calculation unit 24 calculates the noise level, and outputs the noise level signal to the enhancement characteristic calculation unit 23 (step S607).

  The calculation method of the noise level in the noise level calculation unit 24 here is arbitrary, and the detection of the transmitted voice is a known technique such as ITU-T recommendation G.264. It is performed by using a VAD (Voice Activity Detector) described in Annex B of 729, etc., and combining generally known level calculation methods.

  In the enhancement characteristic calculation unit 23, enhancement for enhancing the received speech signal in the speech enhancement unit 21 based on the noise level signal, the output signal from the speech encoder 5, and the output signal of the enhancement amount control unit 22 described in FIG. The characteristic is calculated and a signal is output to the voice enhancement unit 21 (step S608).

  Based on this emphasis characteristic, the received speech signal output from the speech decoder 5 is enhanced by the speech enhancement unit 21 (step S609), and the standby state is returned when the call ends (step S610) (step S611).

  Here, selection of reception clarity improvement function and parameter setting will be described with reference to FIG.

  FIG. 7 shows an operation for selecting the setting of the reception intelligibility improvement function during a call and a parameter for controlling the amount of enhancement when the setting of the reception intelligibility improvement function is selected. The operation will be described.

  When the mobile terminal changes from the standby state (step S701) to the telephone conversation state (step S702), the CPU 1 controls the display unit 3 to display a screen for selecting the effect of the reception clarity improvement function (step S703). In accordance with the displayed screen display, the function key of the operation unit 4 is pressed to select the effect (step S704).

  Next, it is determined whether or not an effect has been selected (step S705). If it is determined that the effect has been selected, the selected parameter is called from the memory (step S706), and the enhancement amount control unit 22 is used as the enhancement amount control parameter. (Step S708).

  If it is determined in step 705 that the intelligibility improvement function has not been selected, the current parameter stored in the RAM or the like is called (S707), and the enhancement amount control unit 22 performs enhancement amount control. It outputs as a parameter (step S708).

  With this operation, the user can select the effect of the received call clarity improvement function. In the present embodiment, the three stages of “OFF”, “normal”, and “strong” have been described. However, the number of stages and the set value name are arbitrary, and are changed in consideration of the hearing ability of the user group of the mobile terminal. be able to.

  Here, the operation of the enhancement amount control parameter will be described. The emphasis amount control parameter is added to the emphasis amount Emp (n) calculated based on the ambient noise level by the emphasis characteristic calculation unit 23, and the emphasis characteristic is calculated.

  For example, when the user sets the clarity improving function to “strong” in step S704, the enhancement amount control parameter serves to increase the enhancement amount calculated by the enhancement characteristic calculation unit 23, and ambient noise is reduced. Even when the emphasis amount calculated by the emphasis characteristic calculation unit 23 is small, the emphasis characteristic is calculated with the emphasis amount corresponding to the emphasis amount control parameter.

  In addition, when the intelligibility improving function is set to “strong”, the amount of enhancement with respect to the ambient noise level is larger than in the case of “normal” setting. However, the sum of the enhancement amount calculated by the enhancement characteristic calculation unit 23 and the enhancement amount for the enhancement amount control parameter is set so as not to exceed the maximum value Emp (Max) of the enhancement amount.

  FIG. 8 is a graph showing the relationship between the ambient noise level and the enhancement amount calculated by the enhancement amount control unit 22. This figure describes the two settings of the clarity improvement function selected by the user. The dashed line indicates “normal” setting for the clarity improvement function, and the solid line indicates “strong” for the clarity improvement function. The case of setting is shown.

  In the “normal” setting, the emphasis amount Emp (n) gradually increases when the ambient noise becomes equal to or higher than a predetermined level N (a), and the emphasis amount Emp (n) is emphasized at a predetermined ambient noise level N (b). The characteristic is saturated at Emp (Max) which is the maximum value.

  In the “strong” setting, the emphasis amount Emp (A) is set to the level of Emp (A) even in a quiet environment where the ambient noise is N (a) or less, and the ambient noise has a predetermined level N (a). If it exceeds, the emphasis amount Emp (n) increases so as to be added to Emp (A), and the emphasis amount Emp (n) is saturated at Emp (Max) at a predetermined ambient noise N (b).

  That is, when the user sets “strong”, the effect of improving the clarity can be obtained at the level of the predetermined enhancement amount Emp (A) even in a quiet environment where the ambient noise is low.

  In other words, the user who has deteriorated hearing due to aging described with reference to FIG. 5 sets the intelligibility improvement function to “enhanced”, and thus the received voice is emphasized even in a quiet environment. Can do.

  Next, details of the operation of the speech enhancement unit 21 will be described with reference to FIG. The speech enhancement unit 21 includes a bandpass filter 211, a level detection unit 212, an enhancement amount control unit 213, and a band signal combination unit 214.

  The received voice signal from the voice decoder 5 is divided into six bands f (1) to f (6) by the bandpass filter 211 having the center frequency in consideration of the voice formant described above by the bandpass filter 211, and level detection is performed. Input to the unit 212. The level of the band signal divided by the level detection unit 212 is detected, and the level of each band is input to the enhancement characteristic calculation unit 23.

  The enhancement characteristic calculation unit 23 calculates a reference level from the signal levels of f (1) and f (2) detected by the level detection unit 212, and based on the signal level of each band and the noise level of the noise level calculation unit 24. The enhancement amount Emp (u) is calculated by calculating the enhancement amount Emp (n) and adding the enhancement amount control parameter output from the enhancement amount control unit 23 based on the user intelligibility improvement function setting described with reference to FIG. ) To calculate the gain β {f (n)} of each band and input the gain β {f (n)} to the emphasis control unit 213 constituted by a voltage control amplifier (VCA).

  However, the sum of the enhancement amount Emp (n) calculated by the enhancement characteristic calculation unit 23 and the enhancement amount Emp (u) corresponding to the enhancement amount control parameter is set so as not to exceed the maximum value Emp (Max) of the enhancement amount. Is done.

  The received voice signal divided by the band pass filter 211 is amplified by the enhancement control unit 213 based on the gain β {f (n)} of each band calculated by the enhancement characteristic calculation unit 22, and is then output by the band signal combining unit 214. The signals are combined and input to the D / A converter 6 shown in FIG. The emphasized audio signal is converted from a digital signal to an analog signal by the D / A converter 6, amplified by the speaker amplifier 7, and output as audio from the speaker 8.

  FIG. 9 explains the effect of frequency spectrum emphasis (formant emphasis), which is one of the operations of the reception intelligibility improving function of the present invention. The broken line graph indicates the characteristic before enhancement, and the solid line graph indicates the characteristic after enhancement processing. In the characteristic after enhancement, the level of the first formant is attenuated according to the reference level, and the second and third characteristics are attenuated. It shows the formant level being amplified to the reference level.

  FIG. 10 explains the effect of increasing the volume, which is another operation of the received call clarity improving function of the present invention. When the ambient noise level detected by the noise level calculation unit 24 exceeds a certain level, a process for increasing the volume is also performed together with frequency spectrum enhancement (formant enhancement). The broken line graph in FIG. 10 is the characteristic before enhancement, and the solid line graph indicates the characteristic after processing. In the characteristic after enhancement, the level of the first formant is attenuated according to the reference level, and the second and second characteristics are attenuated. 3 shows that the formant level 3 is amplified to the reference level and the volume is increased. The received sound can be clearly heard even in an environment where the ambient noise is large by the volume adjustment described above.

  As described above, according to the present invention, in a portable terminal having a function for improving the intelligibility of speech, the speech intelligibility is improved by adjusting the reception volume when the ambient noise is large and the improvement of the speech intelligibility by formant enhancement according to the ambient noise. There is an effect of improvement.

  In addition, it is possible to select the effect of improving the intelligibility according to the setting of the user, and there is an effect that the intelligibility of the received voice can be improved according to the user's hearing even in a quiet environment with little ambient noise. As shown in FIG. 8, the effect of improving the clarity can be changed by setting the clarity improving function.

  That is, when the user sets “strong”, the effect of improving the clarity can be obtained even in a quiet environment where the ambient noise is low.

  In addition, as an effect described in the second embodiment, the user who has deteriorated hearing due to aging described with reference to FIG. It is possible to obtain an effect that the voice is emphasized and easy to hear.

(Embodiment 2)
According to the second embodiment of the present invention, the effect selection of the reception clarity improving function is performed based on the age of the user.
This makes it possible to adjust the enhancement level of the received call clarity improving function based on the age input by the user.

  The operation when the user inputs the age when selecting the effect of the reception clarity improving function, selection of the reception clarity improving function, and parameter setting will be described with reference to FIG.

  When the portable terminal changes from the standby state (step S1101) to the call state (step S1102), a screen display for selecting the age of the user is displayed on the display unit 3 under the control of the CPU 1 (step S1103).

  The user selects an effect by pressing a key on the operation unit 4 in accordance with the displayed screen display (step S1104). In step S1105, it is determined whether or not an age has been input, and if it is determined that an input has been made, a parameter corresponding to age is called from the memory (step S1106) and output to the enhancement amount control unit 22 as an enhancement amount control parameter (step S1106). S1108).

  If it is determined in step S1105 that the reception clarity improvement function has not been selected, the current parameter stored in the RAM or the like is called (step S1107), and the enhancement amount control unit 22 receives the enhancement amount. It outputs as a control parameter (step S1108).

  Here, the emphasis amount control parameter used is calculated based on the increase in the minimum audible limit due to aging in FIG. 5, and is considered so as to correct the deterioration of the audibility of auditory treble due to aging. Parameter.

  With this operation, it is possible to correct deterioration of the ease of hearing of high-pitched sounds by the process of improving the intelligibility by the reception intelligibility improving function, and to improve the ease of hearing of the received sound.

It is a block diagram which shows the structure of the portable terminal with a voice emphasis function. It is a block diagram which shows an audio | voice emphasis part. It is a figure which shows the amplitude with respect to a frequency. It is a figure for demonstrating the principle of emphasis of a frequency spectrum (formant emphasis). It is a figure which shows the average raise of the minimum audible limit by age on the basis of the minimum audible limit around 20 years old. It is a flowchart figure for demonstrating the basic operation | movement of the received call clarity improvement function in this embodiment. It is a figure for demonstrating the operation | movement which outputs the parameter for controlling the emphasis amount at the time of selecting the setting of a call intelligibility improvement function to an emphasis amount control part. It is a figure showing the relationship between the ambient noise level and the enhancement amount calculated by the enhancement amount control unit. It is a figure for demonstrating the effect of the emphasis of a frequency spectrum (formant emphasis) which is one of the operation | movement of the reception clarity intelligibility function of this invention. It is a figure for demonstrating the effect of the volume increase which is another operation | movement of an incoming call intelligibility improvement function. It is a flowchart figure which shows the operation | movement when a user inputs an age when selecting the effect of an incoming call clarity improvement function, selection of an incoming call clarity improvement function, and a process about parameter setting.

Explanation of symbols

1 CPU
2 Radio section 3 Display section 4 Operation section 5 Audio decoder 20 DSP (digital signal processor)
DESCRIPTION OF SYMBOLS 9 Microphone 10 Microphone amplifier 11 A / D converter 12 Voice encoder 6 D / A converter 7 Speaker amplifier 8 Speaker 21 Voice enhancement part (voice enhancement means)
22 Emphasis amount control unit (enhancement amount control means)
23. Emphasis characteristic calculation unit (emphasis characteristic calculation means)
24 Noise level calculation unit (noise level calculation means)
211 Band pass filter 212 Level detection unit (level detection means)
213 Enhancement control unit 214 Band signal combining unit

Claims (10)

A noise level calculation means for estimating the ambient noise characteristics of the mobile terminal user;
An emphasis amount control means for receiving a selection input of the emphasis amount of the user, setting a parameter, and controlling the emphasis amount according to the setting;
An emphasis characteristic calculating means for calculating an emphasis characteristic of the received voice signal based on the characteristic of the received signal, the calculated characteristic of the ambient noise, and the set parameter ;
Voice enhancement means for enhancing and outputting the received voice signal based on the enhancement characteristics ;
The voice enhancement means has level detection means for detecting the level for each band of the received voice,
Based on the detected level for each band, voice emphasis is controlled,
Has a bandpass filter with a center frequency that takes into account the voice formant,
The band is divided by the bandpass filter, the level detection unit performs level detection of each band, the enhancement characteristic is calculated, and the amplitude of each band is adjusted,
A reference level is calculated from the signal level detected by the level detection means,
Calculate the enhancement amount based on the signal level of each band after the division and the noise level calculated by the noise level calculation means,
Calculate the gain of each band based on the enhancement amount obtained by adding the parameters output from the enhancement amount control means,
A speech emphasizing apparatus, wherein the sum of the emphasis amount calculated by the emphasis characteristic calculating means and the emphasis amount for the emphasis amount control parameter is set so that the maximum value of the emphasis amount does not exceed .   The selection of the enhancement amount includes at least a weaker and a stronger selection,
  In the case where the enhancement is set to be strong, the enhancement amount for the ambient noise level is set so that the sum of the enhancement amount calculated by the enhancement characteristic calculation unit and the enhancement amount for the enhancement amount control parameter does not exceed the maximum value of the enhancement amount. The speech enhancement apparatus according to claim 1, wherein the speech enhancement apparatus is made larger than a case where the weak setting is made.   A noise level calculation means for estimating the ambient noise characteristics of the mobile terminal user;
  An emphasis amount control means for receiving a user's age or age group selection input, setting a parameter, and controlling the emphasis amount according to the setting,
  An emphasis characteristic calculating means for calculating an emphasis characteristic of the received voice signal based on the characteristic of the received signal, the calculated characteristic of the ambient noise, and the set parameter;
  Voice enhancement means for enhancing and outputting the received voice signal based on the enhancement characteristics;
Have
  The voice enhancement means has level detection means for detecting the level for each band of the received voice,
  Based on the detected level for each band, voice emphasis is controlled,
  Has a bandpass filter with a center frequency that takes into account the voice formant,
  The band is divided by the bandpass filter, the level detection unit performs level detection of each band, the enhancement characteristic is calculated, and the amplitude of each band is adjusted,
  A reference level is calculated from the signal level detected by the level detection means,
  Calculate the enhancement amount based on the signal level of each band after the division and the noise level calculated by the noise level calculation means,
  Calculate the gain of each band based on the enhancement amount obtained by adding the parameters output from the enhancement amount control means,
  A speech emphasizing apparatus, wherein the sum of the emphasis amount calculated by the emphasis characteristic calculating means and the emphasis amount for the emphasis amount control parameter is set so that the maximum value of the emphasis amount does not exceed.   A portable terminal comprising the speech enhancement device according to any one of claims 1 to 3.   A noise level calculation step for estimating the ambient noise characteristics of the mobile terminal user;
  An emphasis amount control step for receiving a selection input of the emphasis amount of the user, setting a parameter, and controlling the emphasis amount according to the setting,
  An enhancement characteristic calculation step of calculating an enhancement characteristic of the received voice signal based on the characteristic of the received signal, the calculated characteristic of the ambient noise, and the set parameter;
  A voice enhancement step of enhancing and outputting the received voice signal based on the enhancement characteristics;
Have
  In the voice enhancement step, level detection is performed to detect the level for each band of the received voice, and voice enhancement is controlled based on the level for each detected band.
  The band is divided by a bandpass filter having a center frequency considering the voice formant, the level detection of each band is performed by the level detection step, the emphasis characteristic is calculated, the amplitude adjustment of each band is performed,
  Calculate a reference level from the signal level detected in the level detection step,
  Calculate the enhancement amount based on the signal level of each band after division and the noise level calculated in the noise level calculation step,
  Calculate the gain of each band based on the enhancement amount obtained by adding the parameters output in the enhancement amount control step,
  A speech enhancement method characterized in that the sum of the enhancement amount calculated in the enhancement characteristic calculation step and the enhancement amount for the enhancement amount control parameter is set so that the maximum value of the enhancement amount does not exceed.   The selection of the enhancement amount includes at least a weaker and a stronger selection,
  When set to be stronger, the enhancement amount for the ambient noise level is set so that the sum of the enhancement amount calculated in the enhancement characteristic calculation step and the enhancement amount for the enhancement amount control parameter does not exceed the maximum value of the enhancement amount. The speech enhancement method according to claim 5, wherein the speech enhancement method is made larger than a case where the weak setting is made.   A noise level calculation step for estimating the ambient noise characteristics of the mobile terminal user;
  An emphasis amount control step that receives a selection input of the user's age or age group, sets a parameter, and controls the emphasis amount according to the setting,
  An enhancement characteristic calculation step of calculating an enhancement characteristic of the received voice signal based on the characteristic of the received signal, the calculated characteristic of the ambient noise, and the set parameter;
  A voice enhancement step of enhancing and outputting the received voice signal based on the enhancement characteristics;
Have
  In the voice enhancement step, level detection is performed to detect the level for each band of the received voice, and voice enhancement is controlled based on the level for each detected band.
  The band is divided by a bandpass filter having a center frequency considering the voice formant, the level detection of each band is performed by the level detection step, the emphasis characteristic is calculated, the amplitude adjustment of each band is performed,
  Calculate a reference level from the signal level detected in the level detection step,
  Calculate the enhancement amount based on the signal level of each band after division and the noise level calculated in the noise level calculation step,
  Calculate the gain of each band based on the enhancement amount obtained by adding the parameters output in the enhancement amount control step,
  A speech emphasizing apparatus, wherein the sum of the emphasis amount calculated in the emphasis characteristic calculation step and the emphasis amount for the emphasis amount control parameter is set so that the maximum value of the emphasis amount does not exceed.   A noise level calculation process for estimating the ambient noise characteristics of the mobile terminal user;
  An emphasis amount control process for receiving a user's selection input of emphasis amount, setting a parameter, and controlling the emphasis amount according to the setting,
  An enhancement characteristic calculation process for calculating an enhancement characteristic of the received voice signal based on the characteristic of the received signal, the calculated characteristic of the ambient noise, and the set parameter;
  Speech enhancement processing for enhancing and outputting the received speech signal based on the enhancement characteristics;
To the computer,
  The voice enhancement processing performs level detection for detecting the level for each band of the received voice, performs voice enhancement control based on the detected level for each band,
  The band is divided by a bandpass filter having a center frequency considering the voice formant, level detection of each band is performed by the level detection process, enhancement characteristics are calculated, amplitude adjustment of each band is performed,
  A reference level is calculated from the signal level detected by the level detection process,
  Calculate the enhancement amount based on the signal level of each band after the division and the noise level calculated in the noise level calculation process,
  Calculate the gain of each band based on the enhancement amount obtained by adding the parameters output in the enhancement amount control process,
  A speech enhancement program characterized in that the sum of the enhancement amount calculated by the enhancement characteristic calculation processing and the enhancement amount for the enhancement amount control parameter is set so that the maximum value of the enhancement amount does not exceed.   The selection of the enhancement amount includes at least a weaker and a stronger selection,
  When the enhancement is set to be high, the enhancement amount for the ambient noise level is set so that the sum of the enhancement amount calculated in the enhancement characteristic calculation process and the enhancement amount for the enhancement amount control parameter does not exceed the maximum value of the enhancement amount. The speech enhancement program according to claim 8, wherein the speech enhancement program is made larger than a case where the weak setting is made.   A noise level calculation process for estimating the ambient noise characteristics of the mobile terminal user;
  An emphasis amount control process that receives a selection input of the user's age or age group, sets a parameter, and controls the emphasis amount according to the setting,
  An enhancement characteristic calculation process for calculating an enhancement characteristic of the received voice signal based on the characteristic of the received signal, the calculated characteristic of the ambient noise, and the set parameter;
  Speech enhancement processing for enhancing and outputting the received speech signal based on the enhancement characteristics;
To the computer,
  The voice enhancement processing performs level detection for detecting the level for each band of the received voice, performs voice enhancement control based on the detected level for each band,
  The band is divided by a bandpass filter having a center frequency considering the voice formant, level detection of each band is performed by the level detection process, enhancement characteristics are calculated, amplitude adjustment of each band is performed,
  A reference level is calculated from the signal level detected by the level detection process,
  Calculate the enhancement amount based on the signal level of each band after the division and the noise level calculated in the noise level calculation process,
  Calculate the gain of each band based on the enhancement amount obtained by adding the parameters output in the enhancement amount control process,
  A speech enhancement program characterized in that the sum of the enhancement amount calculated by the enhancement characteristic calculation processing and the enhancement amount for the enhancement amount control parameter is set so that the maximum value of the enhancement amount does not exceed.

Images