JP5316560B2 - Volume correction device, volume correction method, and volume correction program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce discomfort by obscuring fluctuation of an output audio volume level at a point of level change, even if a level of an input audio signal is considerably varied. <P>SOLUTION: A volume correction apparatus includes: a first component gain control section which gain-controls and outputs a first component subject signal with a part of a plurality of audio components of an input audio signal including the plurality of audio components as a main component; a first component gain control signal generation section for generating a first component gain control signal so as to fix an output level of the first component subject signal in the first component gain control section; and another component gain control section which gain-controls and outputs any audio component other than the first component of the input audio signal on the basis of the first component gain control signal. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a volume correction device, a volume correction method, and a volume correction program that are suitable for application to an audio output unit of an electronic device typified by, for example, a television broadcast receiver.

  When the broadcast channel received by the TV broadcast receiver is switched, or when a plurality of input devices are switched at the AV center in the AV (Audio-Visual) system, the output volume greatly changes due to the level difference between contents. May occur.

  In such a case, the user needs to adjust the volume by operating the volume using a remote controller or the like in order to obtain his preferred volume, and may feel annoying.

  Also, even within the same content (for example, within the same broadcast channel or within the same broadcast program), the output volume may change due to changes in the commercial (CM) part or scene, which may be uncomfortable.

  Various sound volume correction methods for solving this problem have been proposed. A volume control method using AGC (Auto Gain Control) as an example is widely known.

  FIG. 28 is a block diagram illustrating a configuration example of a volume correction unit using this AGC. The example of FIG. 28 is a case where volume correction is performed on the input audio signals SiL and SiR of the left and right two channels.

  That is, in this example, the left and right two-channel input audio signals SiL and SiR are supplied to variable gain amplifiers 1L and 1R whose gains are variably controlled by a gain control signal, respectively.

  Also, the left and right two-channel input audio signals SiL and SiR are added to each other by the adder 2. The added output signal from the adder 2 is multiplied by ½ gain by the amplifier 3 and then supplied to the average level detector 4. The average level detector 4 detects the average level of the added output signal. Is done.

  Then, the average level detected by the average level detection unit 4 is supplied to the gain control signal generation unit 5. The gain control signal generator 5 compares the average level from the average level detector 4 with a predetermined reference level, and uses the comparison result to make the difference between the two levels zero. A signal is generated and supplied to the variable gain amplifiers 1L and 1R.

  The gains of the variable gain amplifiers 1L and 1R are variably controlled by the gain control signal from the gain control signal generation unit 5. In this case, the left and right two-channel input audio signals SiL and SiR are gain-controlled in the variable gain amplifiers 1L and 1R so that the average level of the added output signal from the adder 2 becomes equal to the reference level.

  As a result, the left and right channel output audio signals SoL and SoR obtained from the variable gain amplifiers 1L and 1R are corrected so that the loud sound is loud and the loud sound is kept small, and the sound volume is automatically set to a constant level. The

  In addition to the above-described AGC volume correction method, various volume correction methods have been proposed. For example, in Patent Document 1 (Japanese Patent No. 3321820), when a compressor is provided and there is a large level of sound input, the output sound level is controlled to be smaller than the input level, and the volume is kept within a certain range. A method for controlling is disclosed.

Japanese Patent No. 3321820

  The conventional volume correction method described above is a method for controlling the volume by monitoring the level of the entire audio signal. For example, in the case of the AGC method, when volume control (gain control) is performed based on the average level of the entire audio signal, the volume control of the entire audio signal is performed, so that no loud noise is generated or the sound is not heard. You can make a small sound.

  By the way, for example, when switching channels in TV broadcast reception, when switching multiple input devices at the AV center, or when changing a commercial (CM) part or scene, a large level difference occurs in the audio signal before and after the change. There is.

  As described above, when the level of the input audio signal greatly fluctuates, it is difficult to completely suppress a sudden change in the audio signal gain at the level change point, and the output audio volume level at the level change point is difficult. The listener may feel uncomfortable in terms of hearing, such as shaking.

  In particular, the conventional sound volume correction method is a method in which the entire audio signal is equally controlled in the same manner, and thus there is a problem that the uncomfortable feeling with respect to the fluctuation of the sound volume level at the sudden change point is conspicuous.

  In view of the above points, the present invention is a volume correction capable of reducing the sense of incongruity by making the output sound volume level fluctuation inconspicuous even when the level of the input sound signal greatly fluctuates. An object is to provide an apparatus and method.

In order to solve the above-described problem, the present invention outputs a first component main signal having a main component of a part of the plurality of sound components of an input sound signal composed of a plurality of sound components by performing gain control. A first component gain control unit; and a first component gain control signal generation unit configured to generate a first component gain control signal that makes the output level of the first component main signal constant in the first component gain control unit; A sound volume correction apparatus comprising: another component gain control unit that performs gain control on a sound component other than the first component of the input sound signal based on the first component gain control signal .

Further, in the sound volume correction device, the first component gain control signal generated by the first component gain control signal generation unit sets an output level of the first component main signal to a constant level. The other component gain control signal generation unit performs control so that other audio signals other than the first component are output at the same level when the correction gain value by the first component gain control signal is within a reference range, When the correction gain value based on the first component gain control signal is outside the reference range, the ratio of the correction gain of the other component gain control signal to the correction gain based on the first component gain control signal is adjusted to a predetermined value. Shall be.

Further, in the sound volume correction device, the first component gain control signal generated by the first component gain control signal generation unit sets an output level of the first component main signal to a constant level. The other component gain control unit generates another component gain control signal having a time delay characteristic that follows with a delay with respect to the gain correction for the first component main signal by the first component gain control signal.

Further, in the sound volume correction device, the other component gain control unit is configured such that the correction gain value based on the other component gain control signal is multiplied by a predetermined reference value to the correction gain value based on the first component gain control signal. Is exceeded, the correction gain value by the other component gain control signal is fixed to the set value.

Further, in the volume correction device, an added output signal obtained by adding the output signal of the first component gain control unit and the output signal of the other component output unit is used as a sound output signal after volume correction.

According to the present invention, since the first component main signal and the audio signal of the other component other than the first component are output in different gain control modes, the level at the level change point at which the level of the input audio signal greatly fluctuates. The fluctuation of the volume level becomes inconspicuous and the uncomfortable feeling is reduced.

1 is a block diagram for explaining a first embodiment of a volume correction apparatus according to the present invention; It is a block diagram for demonstrating the example of the electronic device to which the volume correction apparatus by this invention is applied. It is a wave form diagram used for operation | movement description of 1st Embodiment of the volume correction apparatus by this invention. It is a block diagram which shows the structural example of the center concentration localization signal generation part in embodiment of FIG. It is a block diagram which shows the other structural example of the center concentration localization signal generation part in embodiment of FIG. FIG. 6 is a block diagram for explaining a configuration example of a part of a center concentration localization signal generation unit in the example of FIG. 5. It is a figure used in order to demonstrate each part of the example of a structure of FIG. It is a figure used in order to demonstrate each part of the example of a structure of FIG. It is a figure used in order to demonstrate each part of the example of a structure of FIG. It is a figure used in order to demonstrate each part of the example of a structure of FIG. It is a figure used in order to demonstrate each part of the example of a structure of FIG. It is a figure used in order to demonstrate each part of the example of a structure of FIG. It is a figure used in order to demonstrate each part of the example of a structure of FIG. It is a block diagram for demonstrating 2nd Embodiment of the volume correction apparatus by this invention. It is a block diagram which shows the 1st structural example of the realistic sound level correction gain production | generation part in 2nd Embodiment. It is a figure used in order to explain the 1st example of composition of a realistic sound level correction gain generation part. It is a figure which shows the flowchart for demonstrating the processing operation in the 1st structural example of a realistic sound level correction gain production | generation part. It is a wave form diagram used for description of operation | movement of 2nd Embodiment of the sound volume correction apparatus by this invention using the 1st structural example of a realistic sound level correction gain production | generation part. It is a block diagram which shows the modification of 2nd Embodiment of the volume correction apparatus by this invention using the 1st structural example of the realistic sound level correction gain production | generation part. It is a block diagram which shows the 2nd structural example of the realistic sound level correction gain production | generation part in 2nd Embodiment. It is a wave form diagram used for operation | movement description of 2nd Embodiment of the volume correction apparatus by this invention using the 2nd structural example of a realistic sound level correction gain production | generation part. It is a block diagram which shows the 3rd structural example of the realistic sound level correction gain production | generation part in 2nd Embodiment. It is a wave form diagram used for description of operation | movement of 2nd Embodiment of the volume correction apparatus by this invention using the 3rd structural example of a realistic sound level correction gain production | generation part. It is a block diagram for demonstrating other embodiment of the volume correction apparatus by this invention. It is a block diagram for demonstrating other embodiment of the volume correction apparatus by this invention. It is a block diagram for demonstrating other embodiment of the volume correction apparatus by this invention. It is a figure which shows the example of the other electronic device to which the sound volume correction apparatus by this invention is applied. It is a block diagram for demonstrating the conventional volume correction apparatus.

  Embodiments of a volume correction device according to the present invention will be described below with reference to the drawings. The embodiment of the volume correction apparatus described below is used in an audio output unit of a television broadcast receiver.

  That is, FIG. 2 is a block diagram illustrating a configuration example of a television broadcast receiver. The television broadcast receiver in the example of FIG. 2 includes a control unit 10 that includes a microcomputer. A remote control receiving unit 11 is connected to the control unit 10, and the remote control receiving unit 11 receives a remote control signal from the remote control transmitter 12 and transmits it to the control unit 10. The control unit 10 executes processing control according to the received remote control signal.

  The control unit 10 supplies a control signal to each unit of the television broadcast receiver, and executes a process of receiving the television broadcast signal and reproducing its video and audio.

  The tuner unit 13 selectively extracts a broadcast channel signal designated by a channel selection control signal according to a user's remote control operation from the control unit 10 from a television broadcast wave signal. The tuner unit 13 demodulates and decodes the video signal and the audio signal from the selected broadcast channel signal, supplies the video signal to the video signal processing unit 14, and the audio signal to the audio signal processing unit 15. Supply.

  In the video signal processing unit 14, under the control of the control unit 10, a predetermined process is performed on the video signal, and the processed video signal is displayed on the display control unit 16 through a display controller 16, for example, an LCD (Liquid Crystal Display). 17 is supplied. As a result, an image of the broadcast program of the selected broadcast channel is displayed on the display 17.

  In addition, the audio signal processing unit 15 performs predetermined processing on the audio signal under the control of the control unit 10. In this embodiment, the audio signal processing unit 15 generates the left and right channel audio signals SiL and SiR from the audio signal from the tuner unit 13 and supplies the processed audio signals SiL and SiR to the volume correction unit 18. To do.

  The volume correction unit 18 is a part to which the volume correction apparatus of this embodiment is applied, and the input audio signals SiL and SiR are volume-corrected and output as output audio signals SoL and SoR as described later. . Then, the output audio signals SoL and SoR from the volume correction unit 18 are supplied to the speakers 19L and 19R to be reproduced acoustically. Thereby, the sound of the broadcast program of the selected broadcast channel is emitted from the speakers 19L and 19R.

  Hereinafter, the volume correction apparatus of this embodiment will be described as a case of the volume correction unit 18.

[First Embodiment of Volume Correction Device]
FIG. 1 is a block diagram showing an example of the overall configuration of a volume correction unit 18 as a first embodiment of the volume correction apparatus of the present invention.

  In the first embodiment, the input audio signal is an audio signal of two left and right channels. The first component main signal is a signal mainly including a human voice component in the left and right two-channel audio signals (hereinafter referred to as a voice main signal). The other audio components other than the first component are so-called real sounds other than the main voice signal in the two left and right channel audio signals. Hereinafter, the signal mainly including the presence sound is referred to as a presence sound main signal.

  As shown in FIG. 1, in this first embodiment, the left and right two-channel input audio signals SiL and SiR are supplied to the voice main signal and the live sound main signal separation unit 20. The separation unit 20 in this example includes a center concentration localization signal detection unit 21 and two subtraction units 22 and 23.

  The center centralized localization signal detector 21 is supplied with both left and right channel input audio signals SiL and SiR, and detects the voice main signal Sv as a center concentrated localization signal localized at the center (center) of the left and right channels. The voice main signal Sv detected by the center concentration localization signal detection unit 21 is supplied to the subtraction units 22 and 23.

  The subtracting unit 22 subtracts the voice main signal Sv from the left channel audio signal SiL to obtain the left channel live sound main signal SsL. Further, the subtracting unit 23 subtracts the voice main signal Sv from the right channel audio signal SiR to obtain the right channel live sound main signal SsR.

  Thus, the separation unit 20 obtains the main voice signal Sv and the left and right channel main sound signals SsL and SsR from the two-channel audio signals SiL and SiR.

  The main voice signal Sv from the separation unit 20 is supplied to the addition units 27 and 28 through the variable gain amplifier 24 as an example of the first component gain control means, and is also supplied to the voice level correction gain generation unit 30. The

  In this example, the voice level correction gain generation unit 30 includes an average level detection unit 31 and a gain control signal generation unit 32. The average level detector 31 detects the average level of the voice main signal Sv and supplies the detected average level to the gain control signal generator 32.

  The gain control signal generation unit 32 generates a gain control signal (voice level correction gain value) Gv for causing the average level of the voice main signal Sv to be a predetermined reference level. Then, the gain control signal generation unit 32 supplies the generated gain control signal Gv to the variable gain amplifier 24.

  Therefore, in the variable gain amplifier 24, the gain control signal Gv controls the gain so that the average level of the voice main signal becomes a constant level (reference level) even if the level of the voice main signal Sv varies greatly. . Thus, the output level of the corrected main voice signal Svc output from the variable gain amplifier 24 is automatically set to a constant level. Then, the corrected main voice signal Svc having a certain level is supplied to the adding units 27 and 28.

  On the other hand, the left-channel live sound main signal SsL from the subtracting unit 22 is supplied to the adding unit 27 as it is through the amplifier 25 having a gain of “1”. Further, the right-channel live sound main signal SsR from the subtractor 23 is supplied to the adder 28 at the same level through the amplifier 26 having a gain of “1”.

  Then, the adder 27 adds the left channel presence sound main signal SsL and the corrected voice main signal Svc, and outputs the volume-corrected left channel output audio signal SoL as the addition output.

  The adder 28 adds the right-channel live sound main signal SsR and the corrected voice main signal Svc, and outputs the right-channel output sound signal SoR whose volume has been corrected.

  For example, it is assumed that the voice main signal Sv and the live sound main signal SsL or SsR from the center concentration localization signal detector 21 have level fluctuations as shown in FIGS. 3 (A) and 3 (B).

  At this time, the voice level correction gain in the variable gain amplifier 24 based on the gain control signal Gv from the voice level correction gain generation unit 30 is as shown in FIG. As a result, the corrected main voice signal Svc from the variable gain amplifier 24 is set to a constant level signal as shown in FIG.

  On the other hand, in this example, the live sound main signals SsL and SsR are set to the same levels through the fixed gain amplifiers 25 and 26 having the gain “1” as shown in FIG. As shown in FIG. 3 (F), the output signal has the same level fluctuation as that shown in FIG. 3 (B).

  As described above, the main voice signal Svc supplied as one input to the adders 27 and 28 is gain-corrected in the first gain control mode so that the output level becomes constant. For this reason, as described in the problem section, when the input audio signals SiL and SiR have a large level change, the volume level may fluctuate at the change point.

  On the other hand, the left channel live sound main signal SsL and the right channel live sound main signal SsR supplied to the adders 27 and 28 as the other input are, in this example, a second gain of a fixed gain “1”. The control mode is at the same level. Therefore, although there is an original level fluctuation of the input audio signal, the volume level does not fluctuate due to the gain control according to the first gain control mode.

  Therefore, the left and right channel output audio signals SoL and SoR from the adders 27 and 28 have the left and right channel presence sound main signal SsL and the right channel presence sound main signal SsR, as the volume level of the corrected voice main signal Svc varies. Will be masked. For this reason, the fluctuation of the volume level of the voice main signal Svc becomes inconspicuous, and the uncomfortable feeling for the listener is reduced.

  As described above, according to this embodiment, the voice main signal is quickly changed to an appropriate level, so that a constant feeling of the voice level can be maintained and a voice such as a dialogue can be easily heard. Furthermore, in this first embodiment, the real sound main signal is gain “1”, and the realism is kept constant by not changing the original level, so that the uncomfortable feeling caused by changing the level is reduced, As a result, a more natural level transition can be realized.

  The first embodiment is effective when the amount of change in the voice main signal level is small.

  In the above example, since the audio signal is acoustically reproduced by the left and right channel speakers, the adders 27 and 28 are provided. However, when a center channel speaker is provided in addition to the left and right channel speakers, the corrected main voice signal is supplied to the center channel speaker, and the output audio signals of the amplifiers 25 and 26 are transmitted to the left and right channels. You may make it supply to a loudspeaker. In this case, the sound output level of the center channel speaker and the sound output sound of the left and right channel speakers are acoustically synthesized, so that the volume level by gain control according to the first gain control mode is achieved. The shaking is masked and not noticeable.

[Configuration Example of Center Concentration Localization Signal Detection Unit 21]
<First example>
FIG. 4 shows a first configuration example of the center concentration localization signal detection unit 21. In this example, the center concentration localization signal detection unit 21 includes an addition unit 211 and an amplifier 212 having a fixed gain “0.5”.

  In the centralized localization signal detection unit 21 of this example, the left and right channel input audio signals SiL and SiR are added by the addition unit 211, and the addition output signal is output through the amplifier 212. An output signal of the amplifier 212 is a voice main signal Sv.

  In the case of the first example, the average value of the voice main signal Sv is equal to the average value of the sum signal of the input audio signals SiL and SiR of the left and right channels. Then, the voice level correction gain generation unit 30 generates the gain control signal Gv so that the average value of the voice main signal Sv becomes a constant level. Therefore, in the case of the first example, the voice level correction gain generation unit 30 performs gain so that the added signal of the left and right channel input audio signals SiL and SiR, that is, the level of the entire input audio signal becomes a constant level. The control signal Gv is also generated.

<Second example>
FIG. 5 shows a second configuration example of the center concentration localization signal detection unit 21. In the second example, the output of the first example is not output as it is, but a signal corresponding to the component of only the center localization component is obtained more than the output of the first example.

  In this example, the center concentration localization signal detection unit 21 includes a gain adjustment amplifier 213 and a center concentration localization rate detection unit 214 in addition to the addition unit 211 and the fixed gain “0.5” amplifier 212 in the first example. With.

  In the center concentrated localization signal detector 21 of this example, the output signal of the amplifier 212 is supplied to the gain adjustment amplifier 213, and the output signal of the gain adjustment amplifier 213 is used as the voice main signal Sv.

  In the center concentration localization signal detector 21 of this example, the left and right channel input audio signals SiL and SiR are also supplied to the center concentration localization rate detector 214. In the center concentration localization rate detection unit 214, a gain control signal Gat for controlling the gain of the gain adjustment amplifier 213 is generated according to the ratio of the signal concentrated in the center with respect to the entire input sound.

  Then, the gain of the gain adjustment amplifier 213 is controlled by the gain control signal Gat from the center concentration localization rate detection unit 214, so that the voice main signal Sv is localized at the center among the outputs of the amplifier 212. It consists of signal components according to the rate. That is, the voice main signal Sv of the second example is a signal composed of signal components that are localized more centrally than in the first example.

  The center concentration localization rate detection unit 214 may have a configuration as shown in FIG. 6, for example.

  That is, the center concentration localization rate detection unit 214 includes band limiting filters 2141 and 2142, a localization direction detection unit 2143, a localization direction distribution measurement unit 2144, and a center gain control signal generation unit 2145.

  The left and right two-channel input audio signals SiL and SiR input to the center concentration localization rate detection unit 214 remove, in the band limiting filters 2141 and 2142, frequency band components that do not feel the localization direction so much, such as low frequency components, for example. Is done.

  The two-channel input audio signals SiL and SiR band-limited by the band-limiting filters 2141 and 2142 are supplied to the localization direction detection unit 2143. The localization direction detection unit 2143 receives the two-channel input audio signals SiL and SiR at the time of detection in the localization direction for each predetermined period according to the level of each level of the band-limited two-channel input audio signals SiL and SiR. Detect the localization direction you have.

  That is, the localization direction detection unit 2143 samples the levels (amplitudes) of the two-channel input audio signals SiL and SiR whose bandwidths are limited at a predetermined sampling period. In this example, the localization direction detection unit 2143 detects the localization direction at the latest sampling time as the current localization direction.

  In this case, the localization direction detecting unit 2143 uses the localization direction at the latest sampling time, the level at the latest sampling time and the level at the previous sampling time for each of the input audio signals SiL and SiR. To detect.

  If the two-channel input audio signals SiL and SiR are digital audio signals, the sampling period can be made equal to the sampling period of the digital audio signal. However, the sampling period may not be equal to one sample period of the digital audio signal, but may be a plurality of sample periods. When the input audio signal of the localization direction detection unit 2143 is an analog signal, it may be converted into a digital audio signal at the input stage of the localization direction detection unit 2143.

  A method of detecting the localization direction in the localization direction detection unit 2143 will be described with reference to FIG. FIGS. 7A and 7B show a coordinate space when the amplitude of the input audio signal SiL of the left channel is taken on the X axis and the amplitude of the input audio signal SiR of the right channel is taken on the Y axis.

  In the localization direction detection unit 2143, first, the respective levels of the input audio signals SiL and SiR of the two channels are acquired at the time of detection in the localization direction for each sampling period, and the corresponding coordinate points are obtained as shown in FIG. , (B), for example, P1, P2, P3, and P4 are plotted. In this example, it is assumed that P4 is a coordinate point at the latest detection time.

  The localization direction detection unit 2143 rotates a straight line represented by y = k · x (k is a constant) (a straight line passing through the intersection point Z between the X axis and the Y axis) by ± 90 ° about the intersection point Z. In other words, when the constant k is changed, the plotted coordinate points P1, P2, P3, and P4 move closest to which constant k straight line (which inclination angle straight line). Is calculated. That is, the constant k of the straight line having the smallest sum of the distances Da1, Da2, Da3, Da4 or the distances Db1, Db2, Db3, Db4 from the straight lines with the constant k changed to the coordinate points P1, P2, P3, P4. calculate.

  Then, the localization direction detection unit 2143 sets the inclination angle corresponding to the calculated straight line constant k as the localization direction at the current time point to be detected. In the example of FIG. 7, the angle of the X axis, that is, the localization direction (left direction) of the left channel is set to 0 °, and the angle θ (hereinafter referred to as the localization angle) θ with respect to the X axis is detected as the localization direction.

  In the example of coordinate points P1, P2, P3, and P4 in the case of FIG. 7A, the localization angle is detected as θa, and in the example of coordinate points P1, P2, P3, and P4 in the case of FIG. The localization angle is detected as θb.

  In this embodiment, in the localization direction detection unit 2143, the level of the 2-channel input audio signal at the present time (latest sampling time) and the level of the 2-channel input audio signal at the past sampling time are used with equal weights. No. In this embodiment, the localization direction detection unit 2143 is configured to increase the weight as the level of the 2-channel input audio signal at the sampling time close to the current time.

  For this reason, in the localization direction detection unit 2143, as shown in FIG. 8, with respect to the sampling value of the level of the two-channel input audio signal, the closer to the current time (in this example, the latest sampling time tn), the greater the weight. In addition, a time window WD1 having the characteristic of an exponential function curve is used.

  In the above description, the current time that is the signal to be processed is the latest sampling time (latest sampling time). However, a delay circuit that delays by a predetermined time τ is provided on the input side of the variable gain amplifier 24 and the amplifiers 25 and 26, and the current time to be processed is set as the time delayed by τ from the input audio signals SiL and SiR. be able to.

  In that case, the localization direction detection unit 2143 can detect the localization direction also using the two-channel input audio signals SiL and SiR after (future) the current time as the signal to be processed. . For example, in the example of FIG. 7, the current time as the processing target signal time may be P2 or P3.

  In that case, a time window WD2 having characteristics of an exponential curve as shown in FIG. 9 is used in place of the time window WD1 described above. The time window WD2 has a characteristic of an exponential function curve in which the weight is the largest at the current time tp that is the signal to be processed, and the weight becomes smaller in the past and future directions as the distance from the current time tp is increased.

  Note that the level of the current 2-channel input audio signal may be used as it is without weighting the levels of the 2-channel input audio signals SiL, SiR at the past and / or future sampling points.

  As described above, the localization direction detection unit 2143 can detect from which direction the two-channel input audio signals SiL and SiR are signals as the localization angle θ.

  However, the detected localization angle θ at the present time limits the localization direction of the input audio signal at one time point to one direction, and does not reflect the strength of the signal in each direction. Therefore, in this embodiment, in view of this point, the localization direction detection result (localization angle θ) of the two-channel input audio signals SiL and SiR detected by the localization direction detection unit 2143 at the present time is the localization direction distribution measurement unit 2144. To be supplied.

  The localization direction distribution measurement unit 2144 obtains a distribution in all directions of the localization angle θ detected by the localization direction detection unit 2143 over a predetermined time interval d, and the localization direction of the two-channel input audio signal is determined. Measure how much angle you have in which angle direction.

  In this case, the predetermined time interval d is selected from several milliseconds to several hundred milliseconds, for example, several tens of milliseconds in this example. In this embodiment, in the localization direction distribution measurement unit 2144, the localization angle θ detected by the localization direction detection unit 2143 in the predetermined time interval d is similar to the characteristic of the weighting factor in the localization direction detection unit 2143. Make weights.

  In other words, the localization direction distribution measurement unit 2144 applies a time window WD3 (see FIG. 10) that is weighted so as to increase exponentially as it approaches the current time tp (in this example, tp = tn (latest sampling time)). To weight.

  As described above, when the time window for weighting by the localization direction detection unit 2143 is set as shown in FIG. 9 by providing the delay time τ for the input audio signal, the localization direction distribution is set. The time window in the measurement unit 2144 is the same as that in FIG. The time interval d in that case is a time interval including both the future and the past from the current time tp. Note that the value may be used as it is without weighting.

FIG. 11 shows an example of a localization direction distribution P (θ), which is a distribution of the localization angle θ obtained by the localization direction distribution measuring unit 2144, and the horizontal axis is based on the X axis (left channel localization direction). And the vertical axis represents the appearance degree (<1) of each localization angle. Here, in this embodiment, the localization direction distribution P (θ) is 1 when the sum is obtained for all localization angles θ, that is,
ΣP (θ) = 1
A distribution is generated so that

  The relationship between the localization angle θ and the localization direction of the audio signal is as shown in FIG. Note that the front direction, the left direction, the right direction, and the like shown in FIG. 12 are direction names based on the listener.

  As described above, the localization direction distribution measurement unit 2144 obtains information on the localization direction distribution P (θ) as shown in FIG. 11 for each current time (current sampling time or current sampling time; processing target signal time). It is done.

  Information on the localization direction distribution P (θ) is supplied to the center gain control signal generation unit 2145. In the center gain control signal generation unit 2145, from the localization direction distribution P (θ) calculated by the localization direction distribution measurement unit 2144, a signal that is localized in the center has a larger gain, and in others, the center has a smaller gain. Generate a gain control signal.

  The center gain control signal generation unit 2145 includes a gain table memory (not shown). In this gain table memory, gain table information K (θ) for generating a gain control signal to be supplied to the gain adjustment amplifier 213 is stored in advance.

  The gain table information K (θ) is a gain characteristic in which weighting is performed in the center localization direction for all localization angles (−45 ° to 135 °). FIG. 13 shows an example of the gain table information K (θ).

  That is, in this example, the gain table information K (θ) has a maximum gain of “1” in the front direction (center direction; θ = 45 °) as shown in FIG. In the localization angle range (0 ° to 45 °) to the left of the center direction and the localization angle range to the left of the center direction (45 ° to 90 °), the gain decreases as the distance from the center direction increases. Gain characteristics.

  In the center gain control signal generation unit 2145, the product of the localization direction distribution P (θ) obtained by the localization direction distribution measurement unit 2144 and the gain value of the gain table information K (θ) for all localization angles. Calculate the sum of.

That is, the center gain control signal generation unit 2145
Gat = Σ (K (θ) × P (θ))
The gain control signal Gat is generated as follows.

  The gain control signal Gat generated by the center gain control signal generation unit 2145 in this way is supplied to the gain adjustment amplifier 213 as an output of the center concentration localization rate detection unit 214.

  Therefore, from the gain adjustment amplifier 213, a voice main signal Sv composed of signal components that are localized more centrally than in the first example is obtained.

  Of course, the center concentration localization signal detection unit 21 is not limited to the first and second examples described above.

[Second Embodiment of Volume Correction Device]
In the first embodiment described above, the gain control mode is performed in which the volume correction is not performed for the live sound main signal. However, in some cases, for example, when the level fluctuation of the input audio signal due to channel switching is large, it is better to perform gain control on the live sound main signal together with the voice main signal. The second embodiment is an example that can cope with such a case.

  The second embodiment described below is a case where the second embodiment is applied to the volume correction unit 18 in the television broadcast receiver shown in FIG. 2, as in the first embodiment.

  FIG. 14 is a block diagram showing an example of the overall configuration of the volume correction unit 18 as the second embodiment. In FIG. 14, the same parts as those of the volume correction unit 18 of the first embodiment shown in FIG.

  In this second embodiment, the left and right channel live sound main signals SsL and SsR from the adders 22 and 23 are variable gains instead of the fixed gain amplifiers 25 and 26 in the first embodiment. Amplifiers 250 and 260 are provided.

  In the second embodiment, in addition to the voice level correction gain generation unit 30 in the first embodiment described above, the gain control signal Gs (real sound level correction gain value) for the real sound main signals SsL and SsR. A live sound level correction gain generation unit 40 is provided.

  Then, the gain control signal Gs from the live sound level correction gain generator 40 is supplied to the variable gain amplifiers 250 and 260, and the live sound main signals SsL and SsR of the left and right channels are different from the voice main signal Sv. Gain control of the gain control mode is performed.

  The live sound level correction gain generation unit 40 receives the gain control signal Gv from the voice level correction gain generation unit 30, performs a process based on the gain control signal Gv, and performs gain correction on the live sound main signal. Gs is generated.

  Since some processing is applied to the gain control signal Gv, the gain control mode for the main voice signal Sv by the gain control signal Gv is different from the gain control mode for the live sound main signals SsL and SsR by the gain control signal Gs. It becomes.

  However, in this case, the gain control mode for the presence sound main signals SsL and SsR by the gain control signal Gs is set so as not to immediately follow a large level fluctuation of the input sound signal. That is, as in the first embodiment, also in the second embodiment, the gain control mode for the main voice signal Sv immediately follows the level fluctuation of the input voice signal and always keeps the output level constant. . However, the gain control mode for the real sound main signals SsL and SsR is different from that and has characteristics that do not immediately follow a large level fluctuation of the input audio signal.

  The configuration for processing the voice main signal Sv in the second embodiment is exactly the same as in the first embodiment. Therefore, the voice main signal Svc supplied as one input to the adders 27 and 28 is gain-corrected in the first gain control mode so that the output level becomes constant. For this reason, as described in the problem section, when the input audio signals SiL and SiR have a large level change, the volume level may fluctuate at the change point.

  On the other hand, in the second embodiment, the main sound signals SsL and SsR of the left and right channels are gain-controlled by the variable gain amplifiers 250 and 260 in a second gain control mode different from the first gain control mode. Then, it is supplied to the adders 27 and 28. Further, in this embodiment, the gain control mode for the presence sound main signals SsL and SsR has a characteristic that does not immediately follow a large level fluctuation of the input audio signal.

  Therefore, the fluctuation of the volume level at the large level change point generated for the voice main signal by the gain control of the first gain control mode does not occur for the live sound main signal.

  For this reason, the output sound signals SoL and SoR of the left and right channels from the adders 27 and 28 are masked by the main sound signals SsL and SsR of the left channel and the right channel of the volume level fluctuation of the corrected voice main signal Svc. Become so. As a result, the fluctuation of the volume level of the voice main signal Svc becomes inconspicuous, and the uncomfortable feeling for the listener is reduced.

[Configuration Example of Realistic Sound Level Correction Gain Generation Unit 40]
<First example>
When the input voice signal level fluctuation or the voice main signal Sv level fluctuation is large and only the output level of the voice main signal Sv is gain controlled to a constant level, the balance with respect to the original input voice signal is deteriorated and the user feels uncomfortable There is.

  This first example is an example for improving this problem. FIG. 15 shows a configuration example of the live sound level correction gain generation unit 40 in the first example. In the first example, the live sound level correction gain generation unit 40 includes a gain value conversion table unit 41. Consists of.

  The gain value conversion table unit 41 receives the gain control signal Gv for the voice main signal Sv as an input signal, and outputs the gain control signal Gs for the main sound main signals SsL and SsR. Is omitted).

  FIG. 16 is a diagram for explaining an example of gain value conversion table information stored in a gain value conversion table memory included in the gain value conversion table unit 41.

  When the level fluctuation of the voice main signal Sv is small or when the level fluctuation of the entire input voice signal (when the centralized localization signal detector 21 is the first example) is small, the voice level correction gain value by the gain control signal Gv is There is no significant change around Gv = 1.

  In such a case, the above-described balance between the main sound signal and the main voice signal is not greatly deviated from the original input voice signal, so that a sense of incongruity is not felt. For this reason, in the range where the level fluctuation is small, the live sound main signals SsL and SsR may be output through an amplifier having a fixed gain “1” as in the first embodiment.

  Therefore, in the example of FIG. 16, in the range of 0.75 ≦ Gv ≦ 1.25, the gain control signal Gs for the live sound main signal is always set to a gain value of Gs = 1.

  When the level fluctuation of the input voice signal or the level fluctuation of the voice main signal Sv deviates from such a small level fluctuation range, in this example, with a predetermined ratio to the gain control signal Gv, Following this, the real sound main signals SsL and SsR are gain-controlled.

  That is, in the example of FIG. 16, in the range where the input level where Gv <0.75 becomes large, the relationship from Gs / Gv = k1 (= 1 / 0.75) is obtained from the gain control signal Gv. A gain control signal Gs for the main sound signals SsL and SsR is output.

  Further, in the range where the input level where Gv> 1.25 is small, the relationship between Gs / Gv = k2 (= 2 / 2.5) is established from the gain control signal Gv to the main sound main signals SsL and SsR. The gain control signal Gs is output.

  By doing this, even if the voice level correction gain fluctuates greatly, the realistic sound level correction gain follows the voice level correction gain with a certain ratio, so the realistic sound main signal level relative to the main voice signal level. Can be prevented from being greatly opened. Therefore, natural level transition can be realized even when the level fluctuation is large.

  The gain value conversion table unit 41 reads out and outputs the gain control signal Gs for the corresponding real sound main signal, using the value of the gain control signal Gv for the voice main signal Sv as the read address input of the gain value conversion table memory. Can be configured.

  Note that the gain value conversion table unit 41 can also be configured as a functional means by software processing calculation. FIG. 17 shows an example of a flowchart of software processing calculation in that case.

  The gain value conversion table unit 41 detects the gain value of the gain control signal Gv for the input voice main signal (step S101). Next, it is determined whether or not the gain value Gv is Gv <0.75 (step S102). When it is determined that Gv <0.75, the real sound main signal is calculated by the calculation of Gs = k1 × Gv. A gain control signal Gs for SsL and SsR is calculated (step S103).

  If it is determined in step S102 that Gv <0.75 is not satisfied, it is determined whether Gv> 1.25 (step S104). When it is determined that Gv> 1.25, the gain control signal Gs for the main sound main signals SsL and SsR is calculated by the calculation of Gs = k2 × Gv (step S105).

  Further, when it is determined in step S104 that Gv> 1.25, it is confirmed that 0.75 ≦ Gv ≦ 1.25, and Gs = 1 is set (step S106).

  After steps S103, 104, and 106, the process returns to step S101 and the above processing is repeated.

  Needless to say, the numerical value of the gain value described above is merely an example, and the present invention is not limited to this. In the range where the level fluctuation around the gain value Gv = 1 is small, that is, in the range of α ≦ Gv ≦ β, 1−α = β−1 in the above example, but 1−α ≠ β Of course, it may be -1.

  Further, the ratio value k1 in the range of Gv <α and the ratio value k2 in the range of Gv> β are examples, and k1 = k2 may be satisfied.

  The sound volume correction processing operation in the case of the first example will be described with reference to the signal waveform timing chart of FIG.

  FIG. 18 is the same as FIG. 3 used in the description of the first embodiment described above. That is, if the voice main signal Sv and the live sound main signal SsL or SsR have level fluctuations as shown in FIGS. 18A and 18B, the voice corresponding to the voice main signal Sv by the gain control signal Gv The level correction gain is as shown in FIG.

  The gain control signal Gv controls the gain of the variable gain amplifier 24. As a result, the corrected main voice signal Svc from the variable gain amplifier 24 is a signal having a constant level as shown in FIG. The

  In this example, the gain control signal Gs for the presence sound main signals SsL and SsR is generated as described above based on the gain control signal Gv, and is as shown in FIG.

  The variable gain amplifiers 250 and 260 are gain controlled by the gain control signal Gs. As a result, the corrected real sound main signals SsLc and SsRc from the variable gain amplifiers 250 and 260 are gain-controlled by the real sound main signals SsL and SsR shown in FIG. 18B, as shown in FIG. Will be.

  As is clear from the above description, the first example is effective when the level of the input voice signal or the voice main signal varies greatly, and the level fluctuation of the input voice signal or the voice main signal Sv is small. In that case, the first embodiment may be left as it is.

  Therefore, it is also possible to detect the level fluctuation of the input audio signal and automatically switch and control the gain control mode for the live sound main signal using the detection result.

  FIG. 19 shows a configuration example in that case. As shown in FIG. 19, a level fluctuation detecting unit 29 for detecting the whole level fluctuation of the input audio signals SiL and SiR of the left and right two channels is provided.

  Further, the live sound level correction gain generation unit 40 of this example sets the gain values of the variable gain amplifiers 250 and 260 to the fixed gain “1” for the live sound main signal, as in the first embodiment. And a state in which gain control is performed as in the second embodiment.

  Then, the level fluctuation detection unit 29 adds, for example, the input audio signals SiL and SiR of the left and right channels, detects the level fluctuation for the added signal, and switches to the real sound level correction gain generation unit 40 from the detection result. A signal SW is supplied.

  When the detected level fluctuation is in a preset small level range, the level fluctuation detection unit 29 sets the gain values of the variable gain amplifiers 250 and 260 to the fixed sound “1” with respect to the live sound level correction gain generation unit 40. A switching control signal SW for setting the state is supplied.

  Further, the level fluctuation detection unit 29 supplies the gain control signal Gs to the variable gain amplifiers 250 and 260 to the live sound level correction gain generation unit 40 when the detected level fluctuation deviates from the small level range. A switching control signal SW for setting the state to be used is supplied.

  Accordingly, according to the example of FIG. 19, when the level fluctuation of the input audio signal is large, the state of the second embodiment is automatically entered, and the problem of the state of only the first embodiment is avoided. Can do.

<Second example>
In the second example, the real sound main signals SsL and SsR are not set to fixed gains as in the first embodiment or the first example, and the gain control of the voice main signal Sv is not performed. The gain is controlled according to. As a result, the entire balance can be kept as the original input audio signal, and natural reproduced audio can be obtained.

  FIG. 20 shows a configuration example of the live sound level correction gain generation unit 40 in the second example. In the second example, the live sound level correction gain generation unit 40 includes a delay time constant processing unit 42. Consists of.

  That is, in the second example, the delay time constant processing unit 42 performs the delay time constant processing on the gain control signal Gv for the voice main signal Sv to generate the gain control signal Gs for the real sound main signals SsL and SsR. Is done. That is, it is possible to obtain a realistic sound level correction gain having a time delay characteristic that follows the voice level correction gain with a delay.

  The volume correction processing operation in the case of the second example will be described with reference to the signal waveform timing chart of FIG.

  FIG. 21 is the same as FIG. 18 used in the description of the first example described above. That is, when the voice main signal Sv and the live sound main signal SsL or SsR have level fluctuations as shown in FIGS. 21A and 21B, the voice corresponding to the voice main signal Sv by the gain control signal Gv. The level correction gain is as shown in FIG.

  The gain control signal Gv controls the gain of the variable gain amplifier 24. As a result, the corrected main voice signal Svc from the variable gain amplifier 24 becomes a signal having a constant level as shown in FIG. To be.

  On the other hand, in the second example, the gain control signal Gs for the live sound main signals SsL and SsR is processed by the delay time constant processing shown in FIG. Thus, the gain value changes with a time delay characteristic having a predetermined time constant.

  By performing gain control of the variable gain amplifiers 250 and 260 with the gain control signal Gs, the corrected live sound main signals SsLc and SsRc from the variable gain amplifiers 250 and 260 are as shown in FIG. Become.

  According to the second example, at the moment when the voice main signal Sv is quickly changed to an appropriate level, the presence sound level correction gain is not changed, and the presence is kept constant. In addition, since the levels of the live sound main signals SsL and SsR are slowly corrected with a delay, it is possible to reduce a sense of incongruity due to a large change in level at the level change point by gain control. As a result, a natural level transition can be realized. Further, since the balance between the voice main signal Sv and the live sound main signals SsL and SsR converges to the balance of the original input audio signal, more natural automatic volume correction can be realized.

<Third example>
In the second example described above, the live sound main signals SsL and SsR are gain-controlled in accordance with the gain control of the voice main signal Sv. Therefore, even when the correction gain of the voice main signal Sv becomes very large or becomes very small, the correction gains for the presence sound main signals SsL and SsR are also in accordance therewith.

  This third example is a modification of the second example, and improves the above problem.

  FIG. 22 shows a configuration example of the live sound level correction gain generation unit 40 in the third example. In addition to the delay time constant processing unit 42, an upper limit correction gain generation unit 43 and a lower limit correction gain generation unit 44 are provided. And are provided.

  The upper limit correction gain generation unit 43 receives the gain control signal Gv for the voice main signal Sv as an input signal, and multiplies the gain control signal Gv by a predetermined reference value Ku (Ku> 1) to obtain the upper limit correction gain UL. Generate. In this example, the reference value Ku is set to Ku = 2. Then, the upper limit correction gain generation unit 43 supplies the generated upper limit correction gain UL to the delay time constant processing unit 42.

  The lower limit correction gain generation unit 44 receives the gain control signal Gv for the voice main signal Sv as an input signal, and multiplies the gain control signal Gv by a predetermined reference value Kb (Kb <1) to set the lower limit correction gain. Generate BL. In this example, the reference value Kb is Kb = 0.5. Then, the lower limit correction gain generation unit 44 supplies the generated lower limit correction gain BL to the delay time constant processing unit 42.

  The delay time constant processing unit 42 in the third example also performs the delay time constant processing on the gain control signal Gv for the voice main signal Sv input thereto, and obtains the gain control signal Gs for the live sound main signal. However, in this third example, the delay time constant processing unit 42 always monitors the upper limit correction gain UL and the lower limit correction gain BL, and the gain control signal Gs always has the upper limit correction gain UL ≧ Gs ≧ lower limit correction gain. Restrict to BL.

  The volume correction processing operation in the case of the third example will be described with reference to the signal waveform timing chart of FIG.

  FIG. 23 is the same as FIG. 21 used in the description of the second example described above. That is, if the voice main signal Sv and the live sound main signal SsL or SsR have level fluctuations as shown in FIGS. 23A and 23B, the voice corresponding to the voice main signal Sv by the gain control signal Gv. The level correction gain is as shown in FIG.

  Then, the gain control signal Gv controls the gain of the variable gain amplifier 24. As a result, the corrected voice main signal Svc from the variable gain amplifier 24 becomes a signal at a constant level as shown in FIG. To be.

  On the other hand, in the third example, the gain control signal Gs for the live sound main signals SsL and SsR is subjected to the delay time constant processing shown in FIG. 23C, and the gain control signal Gv shown in FIG. Thus, the gain value changes with a time delay characteristic having a predetermined time constant. As shown in FIG. 23D, the gain control signal Gs in this case is limited so as not to be larger than the upper limit correction gain UL and smaller than the lower limit correction gain BL.

  That is, as shown in FIG. 23D, in the section from the time point t1 to the time point t2, the gain control signal Gs satisfies the upper limit correction gain UL ≧ Gs ≧ lower limit correction gain BL. This is the same as the case (FIG. 21D).

  However, when the time point t2 is passed, the lower limit correction gain BL becomes larger than the value before the time point t2, and the gain value Gs becomes equal to or lower than the lower limit correction gain BL. Therefore, the delay time constant processing unit 42 starts the delay time constant processing for the gain control signal Gv at the time t2 with the gain value Gs as the lower limit correction gain BL and the lower limit correction gain BL as a starting point.

  In the example of FIG. 23, when the time point t3 is passed, the upper limit correction gain UL becomes lower than the value before the time point t3, and the gain value Gs becomes equal to or higher than the upper limit correction gain UL. Therefore, the delay time constant processing unit 42 starts the delay time constant processing for the gain control signal Gv at the time point t3 with the gain value Gs as the upper limit correction gain UL and the upper limit correction gain UL as a starting point.

  By controlling the gains of the variable gain amplifiers 250 and 260 with the gain control signal Gs, the corrected real sound main signals SsLc and SsRc from the variable gain amplifiers 250 and 260 are as shown in FIG. Become.

  According to the third example, since the level of the live sound main signal does not greatly open relative to the voice main signal level, a natural level transition can be realized even when the amount of change in the voice level is large. Will be able to. Further, since the balance between the voice main signal Sv and the live sound main signals SsL and SsR converges to the original balance, more natural automatic volume correction can be realized.

  Further, even when the correction gain of the voice main signal Sv becomes very large or very small, the correction gain Gs for the main sound main signals SsL and SsR is limited to a predetermined level range. This also contributes to the realization of natural automatic volume correction.

  In the description of the third example, both the upper limit correction gain and the lower limit correction gain are set. However, only one of them may be set to limit the gain level range. good.

  In the above description, the first to third examples of the live sound level correction gain generation unit 40 are provided independently to generate the gain control signal Gs for the live sound main signal. However, for the live sound main signal in the first embodiment, there are four types of cases: the fixed gain “1” and the first to third examples of the live sound level correction gain generation unit 40 described above. Each may be provided in the volume correction unit 18 so that it can be switched.

  As a switching method, a switching operation unit is provided in the operation means, and a method of automatic switching as follows can be adopted as well as a method of manual switching by the user as appropriate.

  For example, an automatic switching method using EPG (Electronic Programming Guide) information included in a television broadcast signal can be employed. That is, for example, a table that associates a method considered to be optimal among the four types of examples of the live sound level correction gain generation unit 40 with a genre of a broadcast program such as drama, sports, and variety is created. Then, EPG information is detected from the TV broadcast signal, the genre of the broadcast program is detected, and the table is referred to, thereby switching to the optimum realistic sound level correction gain generation method among the four types. .

  Further, for example, identification information for specifying an optimum realistic sound level correction gain generation method among the above four types is recorded in advance on DVD content, for example. On the other hand, the DVD playback apparatus holds correspondence information between this identification information and the four types of realistic sound level correction gain generation methods. Then, during playback, the DVD playback device acquires the identification information from the DVD and refers to the correspondence information based on the acquired identification information to determine which live sound level correction gain generation method to use. To.

  In addition, by including identification information for identifying a similar realistic sound level correction gain generation method for each broadcast program in a part of the EPG information, any realistic sound level correction is similarly performed for a television broadcast program. It can be determined whether to use the gain generation method.

[Other Embodiments]
<Other separation examples>
In the first and second embodiments described above, the first component main signal is a voice main signal, and the signal mainly including the other components is a real sound main signal. However, it is not limited to this method. For example, the input audio signal is divided into a middle band component and a band component other than the middle band component, and the gain control of the first gain control mode and the second gain control mode which are different from each other is performed. It can also be.

  Further, in the above embodiment, the audio signal is for the left and right channels, but it goes without saying that the audio signal subject to volume correction of the present invention may be a monaural audio signal.

  FIG. 24 shows another example of separation of the input audio signal, in which the monaural input audio signal is separated by the frequency band as described above. Note that the example of FIG. 24 is an example when applied to the above-described second embodiment. Of course, it can be applied to the first embodiment.

  That is, as shown in FIG. 24, in the separation unit 50 in this example, the monaural input audio signal Si is supplied to a band-pass filter 51 for extracting a mid-frequency component of the audio signal, and thereby the audio A midband main signal Sm consisting only of the midband components of the signal is obtained. This mid-band main signal Sm is supplied to the variable gain amplifier 53.

  Then, the middle band main signal Sm from the bandpass filter 51 is supplied to the subtracting unit 52 and subtracted from the input voice signal Si to obtain the high frequency / low band component main signal Shl of the input voice signal Si. The high-frequency / low-frequency component main signal Sh1 is supplied to the adding unit 55 through the variable gain amplifier 54.

  In this example, the mid band main signal Sm from the band pass filter 51 is supplied to the mid band level correction gain generator 56. In this example, the mid-level correction gain generator 56 detects the average level of the mid-band main signal Sm, and makes the average level equal to the reference level, thereby making the output level of the mid-band main signal Sm constant. A gain control signal Gm for generating a level is generated. This gain control signal Gm serves as a mid-range level correction gain.

  Then, the mid-range level correction gain generator 56 supplies the generated gain control signal Gm to the variable gain amplifier 53, and controls the gain of the mid-band main signal Sm so that the output level thereof is a constant level.

  In this example, the gain control signal Gm generated by the mid-range level correction gain generator 56 is supplied to the high-frequency / low-frequency level correction gain generator 57. In the high frequency / low frequency level correction gain generation unit 57, the gain control signal Ghl (high frequency / low frequency level correction gain) for the high frequency / low frequency main signal is the same as in the case of the second embodiment described above. Is generated.

  Then, the high frequency / low frequency level correction gain generating unit 57 supplies the generated gain control signal Ghl to the variable gain amplifier 54, and the high frequency / low frequency main signal Sh1 is the same as in the second embodiment described above. And gain control.

  In this way, the adder 55 adds the mid-band main signal whose gain has been corrected in the first gain control mode and the high-frequency / low-band main signal whose gain has been corrected in the second gain control mode. A signal So is obtained.

  Therefore, in the example of FIG. 24, as in the above-described embodiment, automatic volume correction that makes the volume level fluctuation due to gain control inconspicuous can be performed.

  In addition to the example shown in FIG. 24, other various audio signal separation methods are possible, such as a method of frequency band separation into two bands, a low band and a high band. Further, instead of separating into two, it may be separated into three or more. In that case, one of the three or more signal components may be set to the first gain control mode, and all other signal components may be set to the second gain control mode. The components may also be set to two or more different gain control modes.

<For multi-channel>
Recently, there are cases where the audio signal is a multi-channel of 3 channels or more, such as a 5.1 channel surround sound signal. In the case of such multi-channel, the input audio signal is already separated. And when a center channel exists in a multichannel, the said center channel can be made into the voice main signal of the above-mentioned embodiment.

  FIG. 25 is a diagram for explaining the outline of the volume correction device when the input audio signal is a 5.1 channel surround audio signal.

  That is, in this example, the audio signals FLi and FRi of the front left and right channels are supplied to the variable gain amplifiers 61 and 62. Further, the audio signals RLi and RRi of the rear left and right channels are supplied to the variable gain amplifiers 63 and 64. The center channel audio signal Ci is supplied to the variable gain amplifier 65. Further, the audio signal LFE (Low Frequency Effect) of the low-frequency dedicated channel is supplied to the variable gain amplifier 66.

  The center channel audio signal Ci is also supplied to the voice level correction gain generator 67. The voice level correction gain generation unit 67 has the same configuration as the voice level correction gain generation unit 30 shown in FIG. 14, and generates a gain control signal Gv. The gain control signal Gv generated by the voice level correction gain generator 67 is supplied to the center channel variable gain amplifier 65.

  The gain control signal Gv generated by the voice level correction gain generation unit 67 is also supplied to the live sound level correction gain generation unit 68. The live sound level correction gain generator 68 has the same configuration as the live sound level correction gain generator 40 shown in FIG. 14, and generates a gain control signal Gs. The gain control signal Gs generated by the live sound level correction gain generation unit 68 is supplied to variable gain amplifiers 61 to 64 and 66 for other than the center channel.

  Then, output audio signals FLo, FRo, RLo, RRo, Co, and Lfo are obtained from the variable gain amplifiers 61 to 66, respectively, and are emitted by the respective speakers.

  According to the example of FIG. 25, the center channel audio signal Ci of the 5.1 channel input audio signals FLi, FRi, RLi, RRi, Ci, and LFi is converted into the first gain control mode by the gain control signal Gv. Gain control. On the other hand, among the 5.1-channel input audio signals FLi, FRi, RLi, RRi, Ci, and LFi, audio signals other than the center channel are different from the first gain control mode by the gain control signal Gs. Gain control is performed in the gain control mode.

  Then, the 5.1 channel output audio signals FLo, FRo, RLo, RRo, Co, and LFO are acoustically reproduced and acoustically synthesized by separate speakers, respectively, so that the sound according to the first gain control mode is obtained. Shake is reduced, and there is no sense of incongruity.

  In the example of FIG. 25, all the audio signals other than the center channel are gain-controlled in the second gain control mode using the gain control signal Gs. However, different gain control modes differ for each channel. Thus, each gain control may be performed. In addition, audio signals other than the center channel may be grouped into two or more groups, and gain control may be performed in different gain control modes for each group.

  In some cases, 5.1-channel multi-channel audio signals are downmixed and reproduced as two channels with two speakers. In that case, the first embodiment or the second embodiment described above may be applied to the two-channel audio signal obtained as a result of the downmix.

  Also in the case of downmixing, the gain control may be performed as shown in FIG. 26 using the center channel audio signal of the 5.1 channel audio signal.

  FIG. 26 is a diagram for explaining the outline of the embodiment of the volume correction apparatus when the 5.1 audio surround audio signal is downmixed and the output is 2 channels. Note that the example of FIG. 24 is an example when applied to the above-described second embodiment. Of course, it can be applied to the first embodiment.

  That is, in the example of FIG. 26, the 5.1-channel surround sound signals FLi, FRi, RLi, RRi, Ci, and LFi are supplied to the downmix unit 71, and the left and right two-channel sound signals Li and Ri are supplied. It is said. In this example, the downmix unit 71 outputs the audio signal Ci of the center channel as it is.

  The left and right channel audio signals Li and Ri from the downmix section 71 are supplied to variable gain amplifiers 72 and 73, respectively. Then, the output signals of the variable gain amplifiers 72 and 73 are supplied to the adders 77 and 78.

  The center channel audio signal Ci from the downmix unit 71 is supplied to the variable gain amplifier 74. Then, the output signal of the variable gain amplifier 74 is supplied to the addition units 77 and 78. The adders 77 and 78 output 2-channel output audio signals SoL and SoR.

  The center channel audio signal Ci from the downmix unit 71 is further supplied to the voice level correction gain generation unit 75. The voice level correction gain generation unit 75 has the same configuration as the voice level correction gain generation unit 30 shown in FIG. 14, and generates a gain control signal Gv. The gain control signal Gv generated by the voice level correction gain generation unit 75 is supplied to the center channel variable gain amplifier 74.

  The gain control signal Gv generated by the voice level correction gain generation unit 75 is also supplied to the live sound level correction gain generation unit 76. The live sound level correction gain generator 76 has the same configuration as the live sound level correction gain generator 40 shown in FIG. 14, and generates a gain control signal Gs. The gain control signal Gs generated by the live sound level correction gain generation unit 76 is supplied to the variable gain amplifiers 72 and 73.

  The example of FIG. 26 also has the same operational effects as described above.

<Non-real-time processing>
The above embodiment is a case in which the gain control is performed by detecting the voice average level and the average level other than the voice in real time for the input voice signal. However, the present invention is not applied only to the case of real-time processing.

  For example, a gain control signal Gv or Gs can be generated for an audio signal recorded on a recording medium and recorded in association with the recording signal. In this case, at the time of reproduction, the volume of the reproduced audio signal can be controlled using the recorded gain control signals Gv and Gs.

  FIG. 27 is a block diagram when the present invention is applied to a recording / reproducing apparatus capable of recording a television broadcast signal on a recording medium such as a hard disk or a DVD (Digital Versatile Disc).

  27 includes a broadcast recording system 81, a playback system 82, a level correction gain generation unit 83, a control unit 84, and an operation unit 85. The operation unit 85 includes, for example, a remote control transmission / reception unit. The control unit 84 is configured by mounting a microcomputer, for example, and performs control on each unit of the recording / reproducing apparatus 80 in accordance with an operation input from the operation unit 85.

  The level correction gain generation unit 83 includes a center concentration localization signal detection unit 21 and a voice level correction gain generation unit 30 if the first embodiment shown in FIG. 1 is applied. If the second embodiment shown in FIG. 14 is applied, the center concentration localization signal detection unit 21, the voice level correction gain generation unit 30, and the live sound level correction gain generation unit 40 Become.

  When a recording instruction operation is performed by the user through the operation unit 85, the control unit 84 controls the broadcast recording system 81 to execute recording of the broadcast program instructed to be recorded.

  In the broadcast recording system 81, the broadcast wave signal of the broadcast program instructed to be recorded by the broadcast receiving unit 811 is received and supplied to the decoding unit 812. In this example, the decoding unit 812 decodes the video signal V1 and the audio signal A1 from the received signal and outputs them. Here, the audio signal A1 is, for example, a left / right 2-channel audio signal.

  The video signal V1 and the audio signal A1 from the decoding unit 812 are recorded and encoded by the recording encoding unit 813 and then recorded on the recording medium 816 through the writing unit 815. As the recording medium 816, for example, a hard disk device is used.

  In this example, the operation unit 85 is provided with a key for designating broadcast program content recorded on the recording medium 816 and a level correction gain generation instruction key. When the user designates the recorded broadcast program content and operates the level correction gain generation instruction key, the control unit 84 makes the reproduction volume of the audio signal of the designated broadcast program content appropriate. Level correction gain generation processing is executed.

  That is, the control unit 84 controls the reproduction system read unit 821, the reproduction decoding unit 822, the level correction gain generation unit 83, and the writing unit 815 to be in an operating state based on the operation input of the level correction gain generation instruction key. .

  Then, the control unit 84 controls the reading unit 821 to read the recording signal of the designated broadcast program from the recording medium 816. The reading unit 821 supplies the read recording signal to the reproduction decoding unit 822. The reproduction decoding unit 822 reproduces and decodes the recording signal, and outputs a reproduction video signal V2 and a reproduction audio signal A2.

  The reproduced audio signal A2 from the reproduction decoding unit 822 is supplied to the level correction gain generation unit 83. The level correction gain generator 83 generates the gain control signals Gv and Gs as described in the first embodiment or the second embodiment.

  Then, the level correction gain generation unit 83 supplies the generated gain control signals Gv and Gs to the writing unit 815. The writing unit 815 records the gain control signals Gv and Gs from the level correction gain generation unit 83 on the recording medium 816 in association with the recording signal being reproduced while being controlled by the control unit 84.

  Next, when a reproduction instruction operation is performed by the user through the operation unit 85, the control unit 84 controls the reproduction system 82 to reproduce the broadcast program instructed to reproduce.

  That is, the control unit 84 controls the reading unit 821 to read the recording signal of the broadcast program specified from the recording medium 816 and the gain control signals Gv and Gs recorded in association with each other. The reading unit 821 supplies the read recording signal to the reproduction decoding unit 822 and supplies the read gain control signals Gv and Gs to the gain control signal reproduction unit 826.

  The reproduction decoding unit 822 reproduces and decodes the recording signal to obtain a reproduction video signal V2 and a reproduction audio signal A2. Then, the reproduced video signal V2 is output through the video signal processing unit 823 and the video output terminal 827. A display device is connected to the output terminal 827, and a playback video of the broadcast program is displayed on the display screen.

  Also, the reproduced audio signal from the reproduction decoding unit 822 is supplied to the volume correction unit 825 through the audio signal processing unit 824. In the case of the first embodiment in FIG. 1, the volume correction unit 825 is configured such that the voice level correction gain generation unit 30 is removed, and in the case of the second embodiment in FIG. For example, the voice level correction gain generation unit 30 and the live sound level correction unit 40 are removed.

  On the other hand, the gain control signal reproduction unit 826 reproduces the gain control signals Gv and Gs from the signal from the reading unit 821. Then, the gain control signal reproduction unit 826 supplies the reproduced gain control signals Gv and Gs to the volume correction unit 825 so as to perform gain control as described in the above embodiment. Therefore, the audio signal obtained from the volume correction unit 825 does not cause a sense of incompatibility even when automatic volume correction is performed in the same manner as in the first embodiment and the second embodiment described above.

  The reproduced audio signal from the volume correction unit 825 is supplied to the speaker through the audio output terminal 828.

  In the example of FIG. 27, the level correction gain generator 83 has the same configuration as that of the first embodiment or the second embodiment described above, but the example of FIG. 27 is a real-time process. Since it is not necessary, processing time is required, but a more accurate configuration can be obtained.

  For example, when the recording / reproducing apparatus 80 has a configuration with sufficient buffer capacity and processing capability, a human voice main signal including a human voice signal is detected by pitch detection while taking the autocorrelation of the voice signal. It can also be detected. It is also possible to detect a human voice main signal including a human voice signal more precisely by performing a cepstrum analysis of a spectrum envelope by FFT (Fast Fourier Transform).

  In the example of FIG. 27, in non-real-time processing, gain control signals Gv and Gs are generated and recorded in association with recording signals. However, the sound volume correction process based on the gain control as described above is performed on the sound signal of the recording signal by non-real time processing, and the sound signal subjected to the sound volume correction process is recorded (recorded) on the recording medium. You may make it fix. In this case, gain control for the audio signal can be performed using the high-accuracy configuration as described above.

  The example of FIG. 27 is a recording / reproducing apparatus that generates a gain control signal by non-real time processing for an audio signal, but the first embodiment and the second embodiment described above are applied to the audio signal to be recorded. It may be applied to a recording / reproducing apparatus that performs volume correction processing in real time.

  In that case, the recording / reproducing apparatus applies volume correction processing in real time to the audio signal decoded by the decoding unit 812 by applying the first embodiment or the second embodiment described above. Then, the volume-corrected audio signal is recorded through the recording encoding unit 813. In the case of such a recording / reproducing apparatus, it is not necessary to record the gain control signals Gv and Gs in association with the recording signal, so that the level correction gain generating unit 83 is unnecessary. Further, it is not necessary to provide the level correction gain extraction unit 826 and the volume correction unit 825 in the reproduction system 82.

[Other Embodiments or Modifications]
In the first and second embodiments described above, the voice level correction gain generation unit 30 sets the output level of the voice main signal to a constant level by setting the average level of the voice main signal to the reference value. I made it. However, the gain control mode for the main voice signal may be gain control such that the entire level of the input voice signal becomes the reference value.

  In the second embodiment described above, the output gain control signal Gv from the voice level correction gain generation unit 30 is supplied to the live sound level correction gain generation unit 40 to perform further processing on the gain control signal Gv. Was added to change the gain control mode. However, the first gain control mode and the second gain control mode do not need to have such a dependency. In short, the first gain control mode for the first component main signal and the second gain control mode for other audio component main signals other than the first component may be different modes as in the above example. That's fine.

  In addition, as described for other methods of voice separation in the separation unit, the voice main signal is an example of the first component main signal, and the live sound main signal is a voice component main signal other than the first component. It is an example. The first component main signal and the audio component main signal other than the first component can be various other signals in the input audio signal. One example is to use one of the multi-channels described above as the first component main signal and the other channels as other audio component main signals other than the first component.

  In the above description, the center concentration localization signal detection unit 21, the voice level correction gain generation unit 30, and the live sound level correction gain generation unit 40 have a hardware configuration including discrete circuit units, but a DSP (Digital (Signal Processor) may be used.

  Needless to say, the center concentration localization signal detection unit 21, the voice level correction gain generation unit 30, and the live sound level correction gain generation unit 40 can be configured by software processing using a computer program. In that case, for example, in the example of FIG. 2, the voice level correction gain generation unit 30 and the live sound level correction gain generation unit 40 are provided as software processing functions by the control unit 10. Then, as shown by a dotted line in FIG. 2, the gain control of the variable gain amplifier included in the volume correction unit 18 is controlled by the gain control signal from the control unit 10.

  If the audio signal is digital signal processing, all of the volume correction unit 18 including the variable gain amplifier can be configured as software processing.

  Needless to say, the electronic apparatus to which the sound volume correcting apparatus according to the present invention is applied is not limited to the television broadcast receiving apparatus shown in FIG.

  20, 50: Separation unit, 21: Center concentrated localization signal detection unit, 24, 250, 260 ... Variable gain amplifier, 25, 26 ... Fixed gain amplifier, 30 ... Voice level correction gain generation unit, 40 ... Real sound level correction gain Generation unit, 27, 28 ... addition unit

Claims (12)

A first component gain control unit that performs gain control and outputs a first component main signal having a part of the plurality of sound components as a main component of an input sound signal composed of a plurality of sound components;
In the first component gain control unit, a first component gain control signal generation unit that generates a first component gain control signal that makes the output level of the first component main signal constant;
Based on the first component gain control signal, another component gain control unit that performs gain control and outputs a sound component other than the first component of the input sound signal;
A volume correction device comprising: The volume correction apparatus according to claim 1,
The first component gain control signal generated by the first component gain control signal generation unit sets the output level of the first component main signal to a constant level, and
The other component gain control signal generation unit performs control so that other audio signals other than the first component are output at the same level when the correction gain value by the first component gain control signal is within a reference range, When the correction gain value based on the first component gain control signal is outside the reference range, the ratio of the correction gain of the other component gain control signal to the correction gain based on the first component gain control signal is adjusted to a predetermined value. A volume correction device. The volume correction apparatus according to claim 1,
The first component gain control signal generated by the first component gain control signal generation unit sets the output level of the first component main signal to a constant level, and
The other component gain control unit generates another component gain control signal having a time delay characteristic that follows with delay with respect to gain correction of the first component main signal by the first component gain control signal. . In the volume correction apparatus according to claim 3,
The other component gain control unit, when the correction gain value by the other component gain control signal exceeds a set value obtained by multiplying the correction gain value by the first component gain control signal by a predetermined reference value A volume correction device for fixing a correction gain value by the other component gain control signal to the set value. In the volume correction apparatus in any one of Claims 1-4,
A volume correction device that uses a summed output signal obtained by adding the output signal of the first component gain control unit and the output signal of the other component output unit as a sound output signal after volume correction. In the volume correction apparatus in any one of Claims 1-4,
A first separation unit that separates a first component main signal from the input audio signal and supplies the first component main signal to the first component gain control unit;
By subtracting the first component main signal from the input audio signal, a second component main signal mainly including other audio components other than the first component is separated and supplied to the other component output unit. Two separation parts;
An adding unit that adds the output signal of the first component gain control unit and the output signal of the other component output unit and uses the added output signal as a volume correction output signal;
A volume correction device comprising: In the volume correction apparatus in any one of Claims 1-4,
The input audio signal comprises a multi-channel audio signal,
The first component main signal is a signal of one channel of the audio signals of the plurality of channels. The volume correction apparatus according to any one of claims 1 to 6,
The first component main signal is a human voice signal as a main component. The volume correction apparatus according to claim 7,
The first component main signal is a center channel signal. The volume correction apparatus according to claim 1,
The volume correction device, wherein the first component main signal is a center concentrated localization signal of the input audio signal. A first component main signal having a part of the plurality of sound components as a main component of an input sound signal composed of a plurality of sound components is output by gain control in the first gain control mode,
Generating a first component gain control signal that makes the output level of the first component main signal constant;
A sound volume correction method for performing gain control on a sound component other than the first component of the input sound signal based on the first component gain control signal and outputting the sound component. A computer that is a volume correction device that corrects the volume by controlling the gain of the input audio signal,
A first component gain control unit that performs gain control and outputs a first component main signal having a part of the plurality of sound components as a main component of an input sound signal composed of a plurality of sound components;
In the first component gain control unit, a first component gain control signal generation unit that generates a first component gain control signal that makes the output level of the first component main signal constant;
Based on the first component gain control signal, another component gain control unit that performs gain control and outputs a sound component other than the first component of the input sound signal;
Volume correction program to function as.

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