JP5626586B2 - Delay measuring apparatus, delay measuring method and computer program - Google Patents

Description

  The present invention relates to an acoustic device, and more particularly, to a delay measurement device that can easily perform measurement for time alignment.

  Multi-channel audio devices such as 2-channel stereo using two speakers and 5.1 channel using five speakers are widely used. When the reproduced sound is viewed with such an acoustic device using a plurality of speakers, the acoustic characteristics change depending on the listening environment. For example, if the distance of each speaker from the listening point is different, the arrival time of the sound from each speaker will be different, the localization feeling will deteriorate, the sound image will be blurred, and the sound will be blurred due to sound shift and phase difference, and playback Sound quality may be degraded.

  For example, as shown in FIG. 13, when an Lch (left channel) speaker 510L and an Rch (right channel) speaker 510R are connected to the acoustic device 500, the distance DL from the Lch speaker 510L to the listening point LP is greater than If the distance DR from the Rch speaker 510R to the listening point LP is long, the sound from the Rch speaker 510R arrives at the listening point LP with a delay, and the sound from the Lch speaker 510L and the sound from the Rch speaker 510R shift.

  In order to solve this problem, an audio device having a time alignment function for adjusting the sound of each speaker to reach the listening point at the same time has been put into practical use. FIG. 14 is a diagram illustrating an example of a conventional acoustic device having a time alignment function. As shown in the figure, the acoustic device 520 includes a measurement unit 521 and an adjustment unit 522. At the time of measurement for time alignment, the sound collection microphone 530 is connected to the measurement unit 521 to listen to the sound collection microphone 530. Place at point LP.

  In such a configuration, the acoustic device 520 performs the following operation. That is, at the time of measurement for time alignment, measurement unit 521 outputs a measurement signal from Lch speaker 510L at time tL0, as shown in FIG. The measurement signal is observed by the sound collecting microphone 530, and the sound arrival time dTL from the Lch speaker 510L to the listening point LP is calculated from the difference between the time tL1 when the measurement signal is observed and the output time tL0.

  Similarly, a measurement signal is output from the Rch speaker 510R at time tR0. The measurement signal is observed by the sound collecting microphone 530, and the sound arrival time dTR from the Rch speaker 510R to the listening point is calculated from the difference between the time tR1 when the measurement signal is observed and the output time tR0. The difference between dTL and dTR corresponds to the shift time dT between the sound from the Lch speaker 510L and the sound from the Rch speaker 510R at the listening point.

  At the time of reproduction, the adjustment unit 522 gives a delay time that eliminates the shift time dT to the Lch or Rch that is the channel to which the sound reaches first, so that the sound from both speakers can be listened to at the same time. Adjusted to reach.

JP 2000-354300 A

  However, in the conventional measurement for time alignment, the difference between the output time of the measurement signal and the observation time must be managed for each channel, and the processing becomes complicated. Therefore, an object of the present invention is to simplify the measurement for time alignment.

In order to solve the above-described problem, the delay measurement apparatus according to the first aspect of the present invention includes a measurement audio output unit that alternately outputs measurement audio from the first channel and the second channel at predetermined intervals, and the measurement The time B from when the sound is collected and the measurement sound of the first channel is observed until the measurement sound of the second channel is observed and the measurement sound of the second channel are observed and then the measurement of the first channel is performed. And a delay amount setting unit for calculating a delay time for the first channel of the second channel based on the time B and the time C. And
In order to solve the above-described problem, a delay measurement method according to a second aspect of the present invention includes a measurement sound output step for alternately outputting measurement sound from a first channel and a second channel at a predetermined interval, The time B from when the sound is collected and the measurement sound of the first channel is observed until the measurement sound of the second channel is observed and the measurement sound of the second channel are observed and then the measurement of the first channel is performed. A measurement step of measuring a time C until the sound for observation is measured, and a delay amount calculating step of calculating a delay time of the second channel with respect to the first channel based on the time B and the time C. To do.
In order to solve the above problem, a computer program according to a third aspect of the present invention provides a measurement sound output step for alternately outputting measurement sound from a first channel and a second channel at a predetermined interval, and the measurement sound. For measuring the first channel after observing the time B from the time when the measurement sound of the first channel is observed to the time when the measurement sound of the second channel is observed and the measurement sound of the second channel Causing the computer to execute a measurement step of measuring a time C until sound is observed, a time B, and a delay amount calculating step of calculating a delay time of the second channel with respect to the first channel based on the time C. Features.

  According to the present invention, measurement for time alignment can be simplified.

It is a block diagram which shows the system structural example at the time of applying the delay measuring apparatus of this invention to an audio equipment. It is a flowchart explaining operation | movement of the audio | voice output part for a measurement in 1st Example. It is a figure which shows a mode that the audio | voice for measurement is output from an Lch speaker, and the audio | voice for measurement is output from an Rch speaker after the predetermined time A. It is a flowchart explaining operation | movement of the measurement part and delay amount setting part in 1st Example. It is a figure explaining the space | interval in which the two audio | voices for measurement were observed. It is a figure explaining the relationship between the difference of the time A and the time B, and a sound arrival time. It is a figure explaining the detection of the sound for a measurement using a correlation coefficient. It is a figure explaining the case where the 1st example is applied to multi-channel. It is a flowchart explaining operation | movement of the audio | voice output part for a measurement in 2nd Example. It is a figure explaining the space | interval in which four measurement sound | voices were observed. It is a flowchart explaining operation | movement of the measurement part and delay amount setting part in 2nd Example. It is a figure explaining the space | interval in which four measurement sound | voices were observed. It is a figure which shows the example from which a sound shifts | deviates by the difference in the distance from a speaker. It is a figure which shows the structure which performs the measurement for the conventional time alignment. It is a figure explaining the measurement for the conventional time alignment.

  Embodiments of the present invention will be described in detail with reference to the drawings. The delay measuring apparatus of the present invention measures a relative difference between channels when the measurement sound output from the speaker for each channel reaches the listening point, and based on the difference, is appropriate for each channel. This is a device for setting a delay amount. The delay measurement apparatus of the present invention measures the relative time difference between channels without measuring the absolute time when the measurement sound output from the speaker for each channel reaches the listening point. The measurement for this can be performed easily.

  FIG. 1 is a block diagram showing an example of a system configuration when the delay measuring device of the present invention is applied to an audio device. The delay measuring device can be applied to a stationary acoustic device, a vehicle-mounted acoustic device, a portable acoustic device, and the like.

  As shown in the figure, the acoustic device 100 according to the present embodiment is a device that reproduces reproduction sound source data 400 desired by a user and outputs reproduced sound from a speaker 200. The reproduction sound source data 400 can read data stored in a recording medium such as a CD, a DVD, or a semiconductor recording device, or can be received wirelessly.

  Hereinafter, a mode in which the audio device 100 reproduces the reproduction sound source data 400 desired by the user is referred to as a reproduction mode, and a mode in which measurement for time alignment is performed and an appropriate delay amount is set is referred to as a measurement mode. . In the reproduction mode, reproduction sound source data 400 is reproduced using the delay amount set in the measurement mode.

  The audio device 100 includes a reproduction unit 110, a delay adjustment unit 120, an audio output unit 130, a delay measurement setting unit 150, and a switching circuit 160. These components are a CPU (Central Processing Unit) and a sound device 100 included in the audio device 100. This is realized by the operation of a DSP (Digital Signal Processor) or the like.

  The reproduction unit 110 reproduces the reproduction sound source data 400 and the measurement sound source data 152 output from the delay measurement setting unit 150. Which of the reproduction sound source data 400 and the measurement sound source data 152 is to be reproduced is determined by a switching circuit 160 that the delay measurement setting unit 150 switches. In the example of this figure, two channels of Lch and Rch are played back in stereo, but monaural playback and multichannel playback such as 5.1ch may be performed.

  The delay adjustment unit 120 delays the sound of Lch or Rch in order to perform time alignment in the playback mode. Specifically, the channel on which the sound reaches earlier is delayed in accordance with the channel on which the sound arrives later. The delay measurement setting unit 150 sets which channel is delayed and to what extent. In the case of three or more channels, the other channels are delayed in accordance with the channel that reaches the latest.

  The audio output unit 130 adjusts the volume of the reproduction sound of the reproduction unit 110 and outputs the sound to the speaker 200. The audio output unit 130 may include a DAC (Digital Analog Converter), an amplification element, and the like, and the volume adjustment is performed according to a volume (not shown) operation from the user, for example.

  The delay measurement setting unit 150 sequentially outputs measurement sound at regular intervals for each channel in the measurement mode, and observes the output sound. Then, based on the output voice interval and the observed voice interval, a relative difference between the channels at which the measurement voice output from the speaker for each channel reaches the listening point LP is calculated. Based on the above, an appropriate delay amount is set for each channel.

  In order to perform this processing, the delay measurement setting unit 150 includes a measurement audio output unit 151, measurement sound source data 152, a measurement unit 153, and a delay amount setting unit 154. The delay measurement setting unit 150 can be realized by a CPU or the like executing a predetermined computer program.

  In the measurement mode, the measurement audio output unit 151 switches the switching circuit 160 so that the reproduction unit 110 reproduces the measurement sound source data 152, and reproduces the measurement audio at predetermined intervals in the order of Lch and Rch. In this example, the order is Lch and Rch, but they may be reversed.

  The measurement unit 153 inputs the sound collected by the sound collection microphone 300 installed at the listening point LP, and observes the measurement sound output from the speaker 200 of each channel. Then, the interval of the observed measurement voice is measured.

The delay amount setting unit 154 uses the interval between the output measurement voices and the measured measurement voice interval to determine the relative time between channels when the measurement voice output from the speaker for each channel reaches the listening point LP. The difference is calculated, and an appropriate delay amount for one of the channels is calculated based on the difference and set in the delay adjustment unit 120. For example, when the Lch sound reaches the listening point LP relatively late with respect to the Rch sound by X milliseconds, a delay of X milliseconds is set for the Rch.
<First embodiment>

  Next, a first example of the operation of the delay measurement setting unit 150 in the measurement mode of the present embodiment will be described. In the first embodiment, measurement sound is output once for each of Lch and Rch. FIG. 2 is a flowchart for explaining the operation of the measurement audio output unit 151 in the first embodiment.

  In the measurement mode, the measurement sound output unit 151 first outputs the measurement sound from the Lch (S101). Then, it waits for a predetermined time A (S102), and outputs a measurement voice from the Rch (S103). The measurement sound is obtained by reproducing data recorded as the measurement sound source data 152, and signals such as a single wave, white noise, pink noise, time stretch pulse, and pulse can be used. The measurement sound output from the Lch and the measurement sound output from the Rch may be the same sound or different sounds. For example, the frequency is determined by the Lch measurement sound and the Rch measurement sound. By differentiating, it is possible to facilitate channel discrimination when received.

  As a result, as shown in FIG. 3, the measurement sound is output from the Lch speaker 200L, and after a predetermined time A, the measurement sound is output from the Rch speaker 200R.

  FIG. 4 is a flowchart for explaining the operations of the measurement unit 153 and the delay amount setting unit 154 in the first embodiment.

  First, the measurement unit 153 monitors the input sound from the sound collection microphone 300 and waits for the measurement sound to be observed (S201). The input voice monitoring may be started when the measurement voice output unit 151 outputs the measurement voice, but it is not necessary to manage the time when the measurement voice is output.

  When the measurement voice is observed (S201: Yes), the measurement unit 153 starts time measurement (S202). Then, it waits for the next measurement voice to be observed (S203). When the measurement voice is observed (S203: Yes), the time measurement is finished (S204). The measured time is a time interval in which two measurement voices are observed, as shown in FIG.

  Next, the delay amount setting unit 154 calculates the difference between the known predetermined time A and the measured time B (S205). Since the two measured voices that were observed were originally output at intervals of the predetermined time A, the difference between the predetermined time A and the measurement time B is that the Lch measurement voice is output from the speaker 200L. This corresponds to the difference between the time required to reach the sound collecting microphone 300 and the time required to reach the sound collecting microphone 300 after the Rch measurement sound is output from the speaker 200R.

  That is, when the time until the measurement sound output from the Lch reaches the listening point LP is dL and the time until the measurement sound output from the Rch reaches the listening point LP is dR, a predetermined time The difference between A and measurement time B being 0 means dL = dR, as shown in FIG. 6A, and the distance from the Lch speaker 200L to the listening point LP and the Rch speaker 200R to the listening point LP. This means that the sound distance is not generated.

  When the measurement time B is longer than the predetermined time A by the time dw, as shown in FIG. 6 (b), it means dL <dR, and the Rch speaker 200R is longer than the distance from the Lch speaker 200L to the listening point LP. The distance from the listening point LP to the listening point LP is longer, and the sound from the Rch speaker 200R arrives with a delay of time dw (= dR−dL).

  On the contrary, when the measurement time B is shorter than the predetermined time A by the time dw, as shown in FIG. 6C, it means dL> dR, and the Rch speaker is longer than the distance from the Lch speaker 200L to the listening point LP. The distance from 200R to the listening point LP is shorter, and the sound from the Lch speaker 200L arrives with a delay of time dw (= dL−dR).

  Then, based on the difference between the calculated predetermined time A and measurement time B, the delay amount setting unit 154 sets an appropriate delay amount for the delay adjustment unit 120 (S206). That is, a delay of time dw is set for the channel where the sound arrives earlier.

  More generally, when the channel that outputs the measurement sound first is the first channel, the channel that outputs the measurement sound after the predetermined time A is the second channel, and the time difference of the measured measurement sound is time B If time A <time B, a time B-time A delay is set for the first channel, and if time A> time B, a time A-time B delay is set for the second channel. Set.

  Here, assuming that the negative delay amount is a delay with respect to the other channel, it can be expressed that a delay of time B-time A is set for the first channel.

  Although the delay amount can be set by the above procedure, it is desirable to measure the time B a plurality of times and set the delay amount using the average value in order to further increase the accuracy of the delay amount to be set. .

Note that, in the measurement mode, the measurement unit 153 can use a correlation coefficient that has been used in the past in order to reliably detect the measurement sound from ambient noise, reflected sound, and the like. For example, when the measurement speech waveform x _i as shown in FIG. 7B is detected from the observed waveform y _i as shown in FIG. 7A, the correlation coefficient as shown in [Equation 1] is used. The sound for measurement can be specified by obtaining i that maximizes the correlation coefficient. In the formula, x bar and y bar mean arithmetic averages of x _i and y _i , respectively.

  In the above example, the case of two channels of Lch and Rch has been described, but the present invention can also be applied to multiple channels. For example, in the case of 5 channels of 1ch to 5ch, as shown in FIG. 8, the measurement audio is sequentially output at a predetermined interval A to 1ch to 5ch, and the measurement audio of 1ch is observed, and then 2ch What is necessary is just to measure the elapsed time until observing the measurement sound of ˜5ch for each of 2ch to 5ch. Note that the interval at which the measurement audio is output from each channel may not be constant, but is output at a predetermined interval A for simplicity.

  By this measurement, the delay time for 1ch from 2ch to 5ch can be calculated. For example, for 1ch and Nch, the measurement voice interval is A × (N−1) hours, and the elapsed time from observing the 1ch measurement voice to observing the Nch measurement voice is dTN. For example, the delay time of Nch with respect to 1ch is obtained as dTN-A × N. Then, the delay amount may be set for each of the other channels so as to coincide with the delay time of the channel having the longest delay time for 1ch.

For example, if the delay time for 1ch from 2ch to 5ch is 1msec, -5msec, 10msec, and -4msec, respectively, 4ch is 10msec and the delay time is the longest. What is necessary is just to set the delay of 10 milliseconds, 9 milliseconds, 15 milliseconds, and 14 milliseconds with respect to 1ch, 2ch, 3ch, 5ch so that it may become a relative delay time.
<Second embodiment>

  Next, a second example of the operation of the delay measurement setting unit 150 in the measurement mode of the present embodiment will be described. In the first embodiment, the measurement sound is output once for each of the Lch and Rch, but in the second embodiment, the measurement sound is output alternately for each of the Lch and Rch twice. For this reason, the freedom degree of a measuring object can be raised. FIG. 9 is a flowchart for explaining the operation of the measurement audio output unit 151 in the second embodiment.

  In the measurement mode, the measurement audio output unit 151 first outputs measurement audio from the Lch (S301). Then, the apparatus waits for a predetermined time A / 2 (S302), and outputs measurement audio from the Rch (S303). Further, it waits for A / 2 for a predetermined time (S304), and outputs measurement sound from the Lch (S305). Then, it waits for a predetermined time A / 2 (S306), and outputs the measurement voice from the Rch (S307).

As a result, as shown in FIG. 10, the measurement sound is output from the Lch speaker 200L, and the measurement sound is output from the Rch speaker 200R after a predetermined time A / 2. Further, after a predetermined time A / 2, that is, after a predetermined time A from when the measurement sound is output from the Lch speaker 200L, the measurement sound is output from the Lch speaker 200L, and after the predetermined time A / 2, that is, The measurement sound is output from the Rch speaker 200R a predetermined time A after the measurement sound is output from the Rch speaker 200R.
The

  FIG. 11 is a flowchart for explaining the operations of the measurement unit 153 and the delay amount setting unit 154 in the second embodiment. In the second embodiment, the time B from when the measurement sound of the Lch speaker 200L is observed until the measurement sound of the Rch speaker 200R is observed and the measurement sound of the Rch speaker 200R are observed and then the Lch speaker 200L. Measurement is performed for time C until the measurement voice is observed.

  First, the measurement unit 153 monitors the input sound from the sound collection microphone 300 and waits for the measurement sound to be observed (S401). The input voice monitoring may be started when the measurement voice output unit 151 outputs the measurement voice, but it is not necessary to manage the time when the measurement voice is output.

  When the measurement voice is observed (S401: Yes), the measurement unit 153 starts time measurement for the time B (S402). Then, it waits for the next measurement voice to be observed (S403). When the measurement voice is observed (S403: Yes), the time measurement for the time B is terminated and the measurement of the time C is started (S404). Then, it waits for the next measurement voice to be observed (S405). When the measurement voice is observed (S405: Yes), the time measurement for the time C is ended (S406). Since the measurement voice is observed once more, the time B may be measured again. Further, only time B or only time C may be measured.

  The measurement result is as shown in FIG. 12, and the time B from when the measurement sound of the Lch speaker 200L is observed until the measurement sound of the Rch speaker 200R is observed and the measurement sound of the Rch speaker 200R are observed. The time C from when the Lch speaker 200L is observed until the measurement sound is observed is measured. Here, the sum of time B and time C coincides with the predetermined time A.

  Next, the delay amount setting unit 154 calculates a relative delay time using the known predetermined time A and the measured time B or time C (S407). The relative delay time can be calculated using any two of the predetermined time A, measurement time B, and time C.

  That is, in the second embodiment, if measurement time B = predetermined time A / 2 (measurement time B = measurement time C and measurement time C = synonymous with predetermined time A / 2), from Lch speaker 200L to listening point LP. Is equal to the distance from the Rch speaker 200R to the listening point LP, and no sound deviation occurs.

  If measurement time B> predetermined time A / 2 (measurement time C <predetermined time A / 2 and measurement time B> synonymous with measurement time C), the Rch speaker is more than the distance from Lch speaker 200L to listening point LP. The distance from 200R to the listening point LP is longer, and the sound from the Rch speaker 200R is delayed by time B-time A / 2 (synonymous with B / 2 time-C / 2 time and A / 2 time-C time). Will be reached.

  Conversely, if measurement time B <predetermined time A / 2 (measurement time C> predetermined time A / 2 and measurement time B <synonymous with measurement time C), Lch is greater than the distance from Rch speaker 200R to listening point LP. The distance from the speaker 200L to the listening point LP is longer, and the sound from the Lch speaker 200L is only time C-time A / 2 (synonymous with C / 2 hours-B / 2 hours and A / 2 hours-B hours). It will arrive late.

  Then, based on the calculated relative delay time, the delay amount setting unit 154 sets an appropriate delay amount for the delay adjustment unit 120 (S408). That is, a delay is set for the channel on which the sound arrives earlier.

  More generally, the channel that outputs the measurement sound at an odd number of times at a predetermined time interval A is a first channel, and the channel that is output an even number of times after a predetermined time A / 2 of the first channel is a second channel, The time difference observed between the first measurement voice and the even measurement voice is time B, and the time difference observed between the even measurement voice and the odd measurement voice is time C.

  In this case, if measurement time B> predetermined time A / 2, measurement time C <predetermined time A / 2, measurement time B> measurement time C, time C−time A / 2 (= C) for the first channel. / 2 hours-B / 2 hours = A / 2 hours-B hours), and measurement time B <predetermined time A / 2, measurement time C> predetermined time A / 2, measurement time B <measurement time C If so, a delay of time C-time A / 2 (= C / 2 time-B / 2 time = A / 2 time-B time) is set for the second channel.

  Here, assuming that the negative delay amount is a delay with respect to the other channel, time C-time A / 2 (= C / 2 time-B / 2 time = A / 2 time-B time) with respect to the first channel. It can also be expressed by setting the delay.

  The second example of the present embodiment has been described above. However, the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the same device is provided with the measurement audio output unit 151 and the measurement unit 153. However, the measurement unit 153 is configured to include the time when the measurement audio output unit 151 outputs the measurement audio. Therefore, it may be configured as a separate device. For example, the measurement unit 153 is configured by a communication terminal device, and the measurement mode operation described above is started by transmitting a measurement sound output command wirelessly or by wire to an acoustic device including the measurement sound output unit 151. You may make it do.

  Further, the relative delay time may be measured by adjusting the output interval of the measurement sound so that the intervals of the observed output sounds are equal.

  Further, when outputting measurement audio from Lch and Rch, the same reproduction may be performed on both channels, and one of them may be muted so that measurement audio is output alternately from Lch and Rch. In this case, a monaural sound source can be used as the measurement sound source data 152.

DESCRIPTION OF SYMBOLS 100 ... Acoustic apparatus 110 ... Reproduction | regeneration part 120 ... Delay adjustment part 130 ... Audio | voice output part 150 ... Delay measurement setting part 151 ... Audio | voice output part 152 for a measurement ... Sound source data for measurement 153 ... Measurement part 153 ... Sound source data for measurement 154 ... Delay Volume setting unit 160 ... switching circuit 200 ... speaker 200L ... Lch speaker 200R ... Rch speaker 300 ... sound collecting microphone 400 ... reproduction sound source data 500 ... acoustic device 510L ... Lch speaker 510R ... Rch speaker 520 ... acoustic device 521 ... measurement unit 522 ... Adjustment unit 530 ... Sound collecting microphone

Claims (3)

  A measurement sound output unit for alternately outputting measurement sound from the first channel and the second channel at predetermined intervals;
  The measurement voice is collected, the time B from when the measurement voice of the first channel is observed until the measurement voice of the second channel is observed, and the measurement voice of the second channel are observed and then the first A measurement unit for measuring time C until the measurement voice of the channel is observed,
  A delay amount setting unit for calculating a delay time of the second channel with respect to the first channel based on the time B and the time C;
  A delay measuring apparatus comprising:   A measurement sound output step for alternately outputting measurement sound from the first channel and the second channel at predetermined intervals;
  The measurement voice is collected, the time B from when the measurement voice of the first channel is observed until the measurement voice of the second channel is observed, and the measurement voice of the second channel are observed and then the first A measurement step for measuring a time C until the measurement voice of the channel is observed;
  A delay amount calculating step of calculating a delay time of the second channel with respect to the first channel based on the time B and the time C;
  A delay measuring method comprising:   A measurement sound output step for alternately outputting measurement sound from the first channel and the second channel at predetermined intervals;
  The measurement voice is collected, the time B from when the measurement voice of the first channel is observed until the measurement voice of the second channel is observed, and the measurement voice of the second channel are observed and then the first A measurement step for measuring a time C until the measurement voice of the channel is observed;
  A delay amount calculating step of calculating a delay time of the second channel with respect to the first channel based on the time B and the time C;
  A computer program for causing a computer to execute.