JP6703840B2 - Sound quality evaluation device - Google Patents

Description

The present invention relates to a sound quality evaluation device that evaluates the sound quality of a speech signal to be evaluated.

When evaluating the sound quality of a radio broadcast, the sounder generally evaluates the sound quality by "subjective" in seven steps shown in Table 1 while listening to the sound of the radio receiver (for example, Non-Patent Document 1). reference).

NHK Radio Technical Textbook, edited by Japan Broadcasting Corporation, Japan Broadcast Publishing Association, October 25, 1993, p40-41

However, since the conventional method is a subjective evaluation, there is a problem in that the results of the actual listening survey vary depending on individuals.

An object of the present invention made in view of such circumstances is to provide a sound quality evaluation apparatus capable of improving the accuracy of sound quality evaluation.

In order to solve the above problems, a sound quality evaluation apparatus according to the present invention is a sound quality evaluation apparatus that evaluates the sound quality of an evaluated audio signal using a reference audio signal, delays the evaluated audio signal, and A delay control unit that outputs a synchronized synchronized voice signal to be evaluated, and noise is added to the reference voice signal so as to approach the synchronized voice signal to be evaluated, and a value indicating the magnitude of the noise is used as a sound quality evaluation index. And a sound quality evaluation unit for outputting.

In order to solve the above-mentioned problems, a sound quality evaluation apparatus according to the present invention is a sound quality evaluation apparatus that evaluates the sound quality of an evaluated audio signal using a reference audio signal, and delays the evaluated audio signal to produce a reference audio signal. A delay control section for outputting a synchronized voice signal under evaluation synchronized with the signal, and an unused voice band of the voice signal under evaluation when the level of the reference voice signal is below a first threshold value. levels were measured in, characterized by Rukoto and a sound quality evaluation unit which outputs a value indicating the magnitude of the level as a quality evaluation index.

In order to solve the above-mentioned problems, a sound quality evaluation apparatus according to the present invention is a sound quality evaluation apparatus that evaluates the sound quality of an evaluated audio signal using a reference audio signal, and delays the evaluated audio signal to produce a reference audio signal. A delay control section for outputting a synchronized voice signal under evaluation synchronized with the signal, and an unused voice band of the voice signal under evaluation when the level of the reference voice signal is below a first threshold value. Is measured, and the difference between the maximum value of the measured level of the synchronized speech signal to be measured and the average value or the minimum value of the level exceeds a second threshold, the synchronized speech signal to be evaluated is A sound quality evaluation unit that determines that the interference wave is superimposed .

In order to solve the above-mentioned problems, a sound quality evaluation apparatus according to the present invention is a sound quality evaluation apparatus that evaluates the sound quality of an evaluated audio signal using a reference audio signal, and delays the evaluated audio signal to produce a reference audio signal. A delay control unit that outputs a synchronized voice signal under evaluation synchronized with a signal, measures the level of the reference voice signal and the level of the synchronized voice signal under evaluation, and obtains a correlation coefficient while moving one in the time direction, A sound quality evaluation unit that outputs a value indicating the maximum correlation coefficient as the sound quality evaluation index.

According to the present invention, the accuracy of sound quality evaluation can be improved.

It is a block diagram which shows the schematic structural example of the sound quality evaluation apparatus which concerns on embodiment of this invention. It is a block diagram which shows the structural example of the sound quality evaluation part in the sound quality evaluation apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the sound quality evaluation method in the sound quality evaluation apparatus which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the sound quality evaluation part in the sound quality evaluation apparatus which concerns on the 2nd Embodiment of this invention. It is a figure explaining the process of the sound quality evaluation part in the sound quality evaluation apparatus which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the sound quality evaluation method in the sound quality evaluation apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structural example of the sound quality evaluation part in the sound quality evaluation apparatus which concerns on the 3rd Embodiment of this invention. It is a figure explaining the process of the sound quality evaluation part in the sound quality evaluation apparatus which concerns on the 3rd Embodiment of this invention. It is a figure which shows the example which graphed the average value of each frequency component calculated in the sound quality evaluation apparatus which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the modification of the sound quality evaluation part in the sound quality evaluation apparatus which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows the sound quality evaluation method in the sound quality evaluation apparatus which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the structural example of the sound quality evaluation part in the sound quality evaluation apparatus which concerns on the 4th Embodiment of this invention. It is a figure explaining the process of the sound quality evaluation part in the sound quality evaluation apparatus which concerns on the 4th Embodiment of this invention. It is a flowchart which shows the sound quality evaluation method in the sound quality evaluation apparatus which concerns on the 4th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, the outline of the sound quality evaluation apparatus according to the embodiment of the present invention will be described. The sound quality evaluation device inputs a sound signal to be evaluated and a reference sound signal for evaluating the sound signal to be evaluated, and compares them to obtain a sound quality evaluation index indicating the sound quality of the sound signal to be evaluated. Is output. The sound quality evaluation index may be of any type as long as it can accurately evaluate the sound quality of the evaluated audio signal. The reference voice signal is a voice signal having the same content as that of the voice signal to be evaluated and having a higher quality than the voice signal to be evaluated. For example, an evaluated audio signal is an audio signal of a radio broadcast obtained by receiving and demodulating an AM or FM broadcast wave, and a reference audio signal is received on the Internet. Let it be voice.

FIG. 1 is a block diagram showing a schematic configuration example of a sound quality evaluation apparatus according to an embodiment of the present invention. As shown in FIG. 1, the sound quality evaluation device 1 includes a delay control unit 11 and a sound quality evaluation unit 12.

The delay control unit 11 delays the evaluated audio signal and outputs the evaluated audio signal synchronized with the reference audio signal (hereinafter, referred to as “synchronized evaluated audio signal”) to the sound quality evaluation unit 12. For example, when the evaluated audio signal is a sound signal of a radio broadcast and the reference audio signal is a signal output after accumulating the audio signal of the Internet radio that simulatively distributes the radio broadcast in a buffer, the evaluated sound signal is used as a reference. Delay to synchronize with the audio signal.

The sound quality evaluation unit 12 inputs the synchronized sound signal to be evaluated and the reference sound signal and compares them to generate a sound quality evaluation index indicating the sound quality of the sound signal to be evaluated and outputs it to the outside. A specific example of the sound quality evaluation unit 12 will be described in the following embodiment.

(First embodiment)
Next, a sound quality evaluation apparatus according to the first embodiment of the present invention will be described. FIG. 2 is a block diagram showing a configuration example of the sound quality evaluation unit 12 in the sound quality evaluation device 1 according to the first embodiment of the present invention. In the example shown in FIG. 2, the sound quality evaluation unit 12 includes a noise addition unit 121 and a noise amount adjustment unit 122.

The noise adding unit 121 adds noise to the reference audio signal.

The noise amount adjusting unit 122 adjusts the noise amount added by the noise adding unit 121. The amount of noise is adjusted so that the reference audio signal approaches the synchronous evaluated audio signal. This adjustment may be performed manually by the measurer while listening to the reference voice signal and the synchronized voice signal to be evaluated, or the difference between the reference voice signal and the synchronized voice signal to be evaluated is less than or equal to a threshold value, or the degree of correlation is more than a threshold value. As described above, automatic adjustment may be performed by calculation.

The noise amount adjustment unit 122 outputs a value indicating the magnitude of noise added to the reference audio signal to the outside as a sound quality evaluation index. Here, the value indicating the magnitude of the noise may be the value of the added noise level itself, or may be an evaluation value indicated in multiple stages based on the added noise. When outputting the evaluation value, the noise amount adjusting unit 122 determines the evaluation value in seven levels as shown in Table 1 according to the magnitude of the added noise, for example. The smaller the noise amount, the better the evaluation value.

Next, a sound quality evaluation method in the sound quality evaluation apparatus 1 according to the first embodiment of the present invention will be described. FIG. 3 is a flowchart showing a sound quality evaluation method in the sound quality evaluation apparatus 1 according to the first embodiment of the present invention.

In step S101, the evaluated audio signal is synchronized with the reference audio signal. For example, the delay control unit 11 performs this process.

In step S102, noise is added to the reference audio signal. For example, the noise adding unit 121 performs this process.

In step S103, the amount of added noise is adjusted. For example, the noise amount adjustment unit 122 performs this processing.

In step S104, the value indicating the magnitude of the noise added in step S103 is output. For example, the noise amount adjustment unit 122 performs this processing.

As described above, in the first embodiment, noise is added to the reference audio signal so as to approach the synchronized evaluated audio signal, and a value indicating the magnitude of the noise is output as a sound quality evaluation index. Therefore, the sound quality of the evaluated voice signal can be accurately evaluated.

(Second embodiment)
Next, a sound quality evaluation apparatus according to the second embodiment of the present invention will be described. The configuration of the sound quality evaluation unit 12 in the sound quality evaluation apparatus 1 is different from that of the first embodiment. FIG. 4 is a block diagram showing a configuration example of the sound quality evaluation unit 12 in the sound quality evaluation device 1 according to the second embodiment. In the example shown in FIG. 4, the sound quality evaluation unit 12 includes a silence determination unit 123 and a level measurement unit 124.

The silence determination unit 123 measures the signal level of the reference voice signal, determines that the reference voice signal is not silent when the level of the reference voice signal exceeds the threshold, and outputs no sound when the level of the reference voice signal is equal to or less than the threshold. Judge that there is. Then, a signal indicating the determination result, that is, a signal indicating whether or not there is silence is output to the level measuring unit 124.

The level measuring unit 124 receives the signal indicating the determination result from the silence determining unit 123, and measures the level (that is, the noise level) of the synchronized speech signal to be evaluated and stores the signal when the signal indicates the silence. Then, the value indicating the magnitude of the measured level is output to the outside as a sound quality evaluation index. Here, the value indicating the magnitude of the level may be an average value, a minimum value, a maximum value, or the like of the measured levels, or may be an evaluation value shown in multiple stages based on the measured levels. Good. When outputting the evaluation value, the noise amount adjusting unit 122 determines the evaluation value in seven levels as shown in Table 1 according to the magnitude of the measured level, for example. The smaller the level, the better the evaluation value.

When the level measuring unit 124 measures the level of the synchronized voice signal to be evaluated, the level measuring unit 124 determines a frequency band other than the frequency band (voice band) of the voice used in the synchronous voice signal to be evaluated, that is, the unused voice band. May be measured. For example, when the evaluated audio signal is an audio signal of a radio broadcast obtained by receiving and demodulating an AM broadcast radio wave, the audio band used in the AM broadcast is 100 Hz to 7.5 kHz. For example, only signals in the frequency band of 8 to 11 kHz may be extracted and measured. When the evaluated audio signal is an audio signal of a radio broadcast obtained by demodulating and demodulating an FM broadcast radio wave, the audio band used in the FM broadcast is 50 Hz to 15 kHz, and therefore, for example, 16 audio signals of the evaluated audio signals are used. You may extract and measure only the signal of the frequency band of-18 kHz. The measurement accuracy can be stabilized by measuring the level of the frequency band other than the used voice band.

FIG. 5 is a diagram for explaining the processing of the sound quality evaluation unit 12 of this embodiment. Since the reference voice signal and the synchronized voice signal to be evaluated are synchronized by the delay control unit 11, when the reference voice signal becomes silent, the synchronous voice signal to be evaluated also becomes silent. However, since it is difficult to synchronize completely, a predetermined time (for example, 0.1 seconds) at the beginning and end of a silent period of a reference audio signal for a predetermined time (for example, 0.7 seconds) or more. It is preferable that the section other than is used as the silent section of the synchronized speech signal to be evaluated, and the level measuring unit 124 measures the level of the synchronized speech signal to be evaluated in this silent section.

Further, when the difference between the maximum value and the average value or the minimum value of the levels of the synchronized speech signal to be evaluated in the silent section exceeds the threshold value, the level measuring unit 124 outputs the synchronized speech signal to be evaluated as shown in FIG. It can be determined that the interference wave is superimposed on. When the level measuring unit 124 determines that the interference wave is superimposed, the level measuring unit 124 performs a specific process. For example, a signal indicating that the interference wave is superimposed may be output, or a value indicating the magnitude of the measured level may not be output.

Next, a sound quality evaluation method in the sound quality evaluation apparatus 1 according to the second embodiment of the present invention will be described. FIG. 6 is a flowchart showing a sound quality evaluation method in the sound quality evaluation apparatus 1 according to the second embodiment of the present invention.

In step S201, the evaluated audio signal is synchronized with the reference audio signal. For example, the delay control unit 11 performs this process.

In step S202, the silent section of the reference audio signal is determined. For example, the silence determination unit 123 performs this process.

In step S203, the level of the silent section of the synchronized speech signal to be evaluated is measured. For example, the level measuring unit 124 performs this process.

In step S204, a value indicating the magnitude of the level measured in step S203 is output. For example, the level measuring unit 124 performs this process.

As described above, in the second embodiment, when the level of the reference audio signal is less than or equal to the threshold value, the level of the synchronized evaluated audio signal is measured, and the value indicating the magnitude of the level is used as the sound quality evaluation index. Output. This focuses on the tendency of the noise level of a voice signal with deteriorated sound quality to increase when there is no sound. Therefore, by measuring the level of the synchronized speech signal under evaluation when there is no sound, the sound quality of the speech signal under evaluation can be accurately evaluated.

(Third Embodiment)
Next, a sound quality evaluation apparatus according to the third embodiment of the present invention will be described. The configuration of the sound quality evaluation unit 12 in the sound quality evaluation apparatus 1 is different from that of the first embodiment. FIG. 7 is a block diagram showing a configuration example of the sound quality evaluation unit 12 in the sound quality evaluation device 1 according to the third embodiment. In the example shown in FIG. 7, the sound quality evaluation unit 12 includes Fourier transform processing units 125-1 and 125-2 and a correlation coefficient calculation unit 126.

The Fourier transform processing unit 125-1 performs Fourier transform on the reference audio signal a plurality of times at predetermined time intervals, and outputs the level for each frequency component to the correlation coefficient calculation unit 126 a plurality of times.

The Fourier transform processing unit 125-2 performs a Fourier transform on the synchronized speech signal to be evaluated a plurality of times at predetermined time intervals, and outputs the level for each frequency component to the correlation coefficient calculator 126 a plurality of times.

The correlation coefficient calculation unit 126 calculates the average value x _i for each frequency component for the level input from the Fourier transform processing unit 125-1 and for each frequency component for the level input from the Fourier transform processing unit 125-2. The average value y _i is calculated, and the correlation coefficient r between the average value x _i and the average value y _i is obtained. The correlation coefficient r represents the strength of the relationship between x _i and y _i , is calculated by the equation (1), and has a value of −1≦r≦1.

Then, the correlation coefficient calculation unit 126 outputs a value indicating the calculated magnitude of the correlation coefficient r to the outside as a sound quality evaluation index. Here, the value indicating the magnitude of the correlation coefficient r may be the value itself of the correlation coefficient r, or may be an evaluation value shown in multiple stages based on the correlation coefficient r. When outputting the evaluation value, the correlation coefficient calculation unit 126 determines the evaluation value in seven stages as shown in Table 1 according to the magnitude of the correlation coefficient r, for example. The larger the correlation coefficient r, the better the evaluation value.

FIG. 8 is a diagram for explaining the processing of the sound quality evaluation unit 12 of this embodiment. In the example shown in FIG. 8, the Fourier transform processing is performed every 0.1 seconds for 0 to 60 seconds for each of the reference speech signal and the synchronized speech signal to be evaluated, and the frequency component is calculated in units of 100 Hz. Then, the average value of the reference voice signal and the synchronized voice signal to be evaluated is calculated in units of 100 Hz.

FIG. 9 is a diagram showing an example in which the average value of each frequency component is graphed, and shows the average value of each frequency component of the reference audio signal and the four types of synchronous evaluated audio signals. In this example, the relative level difference from the time signal sound of the reference voice signal is shown. Correlation coefficients between the average value of each frequency component of the four types of synchronous evaluated voice signals and the average value of each frequency component of the reference voice signal are 0.978, 0.974, 0.962 and 0.955, respectively. is there. In addition, the evaluation values of seven stages shown in Table 1 are determined based on the correlation coefficient, and the evaluation values are set to 4, 3+, 3-, 2 in the high correlation coefficient.

Next, a modified example of the sound quality evaluation apparatus according to the third embodiment of the present invention will be described. FIG. 10 is a block diagram showing a modification of the sound quality evaluation apparatus according to the third embodiment. In the example shown in FIG. 10, the sound quality evaluation unit 12 further includes a silence frequency level measurement unit 127 in addition to the configuration shown in FIG. 7.

Since the audio band used in FM radio is 50 Hz to 15 kHz, the level of frequency components other than the band is a noise component. It is considered that accurate sound quality evaluation can be performed by comparing only noise components.

Therefore, the silence frequency level measuring unit 127 determines, among the levels of the frequency components of the synchronized speech signal to be evaluated input from the Fourier transform processing unit 125-2, the frequency components other than the voice band included in the synchronized speech signal to be evaluated ( A value indicating the level of the (silent frequency component) is output to the outside as a sound quality evaluation index. Here, the value indicating the magnitude of the level may be an average value, a minimum value, a maximum value, or the like of the measured levels, or may be an evaluation value shown in multiple stages based on the measured levels. Good. When outputting the evaluation value, the silence frequency level measuring unit 127 determines the evaluation value in seven stages according to the magnitude of the measured level, for example. The smaller the level, the better the evaluation value.

In stereo broadcasting on the FM radio, a pilot signal may be added at 19 kHz as shown in FIG. In this case, the silent frequency level measuring unit 127 measures the level at frequency components of 16 kHz to 18 kHz, excluding 19 kHz. Note that the sound quality evaluation unit 12 may be able to select in advance whether to output only one or both of the value obtained by the correlation coefficient calculation unit 126 and the value obtained by the silence frequency level measurement unit 127.

Next, a sound quality evaluation method in the sound quality evaluation apparatus 1 according to the third embodiment of the present invention will be described. FIG. 11 is a flowchart showing a sound quality evaluation method in the sound quality evaluation apparatus 1 according to the third embodiment of the present invention.

In step S301, the evaluated audio signal is synchronized with the reference audio signal. For example, the delay control unit 11 performs this process.

In step S302, the reference voice signal and the synchronized voice signal to be evaluated are Fourier transformed. For example, this processing is performed by the Fourier transform processing units 125-1 and 125-2.

In step S303, the average value of the level of each frequency component of the reference voice signal and the synchronized voice signal to be evaluated is calculated. For example, this processing is performed by the Fourier transform processing units 125-1 and 125-2 or the correlation coefficient calculation unit 126.

In step S304, the correlation coefficient of the average value of each frequency component is calculated. For example, the correlation coefficient calculation unit 126 performs this processing.

In step S305, a value indicating the magnitude of the correlation coefficient calculated in step S304 is output. For example, the correlation coefficient calculation unit 126 performs this processing.

Further, step S306 may be provided to measure the level of the silent frequency component of the synchronized voice signal to be evaluated. For example, the silent frequency level measuring unit 127 performs this process.

In step S307, a value indicating the level magnitude of the silent frequency component measured in step S306 is output. For example, the silent frequency level measuring unit 127 performs this process.

As described above, in the third embodiment, the correlation coefficient between the frequency component obtained by Fourier transforming the reference voice signal and the frequency component obtained by Fourier transforming the synchronized voice signal under evaluation is calculated, and A value indicating the magnitude of the relation number is output as a sound quality evaluation index. Therefore, it is possible to accurately perform voice evaluation based on the degree of similarity with the reference voice signal.

Further, in the modification of the third embodiment, among the frequency components obtained by Fourier transforming the synchronized speech signal to be evaluated, a value indicating the level of the unused voice band is output as the sound quality evaluation index. .. Therefore, the sound quality of the evaluated audio signal can be accurately evaluated based on the silent frequency component of the synchronized evaluated audio signal.

(Fourth Embodiment)
Next, a sound quality evaluation apparatus according to the fourth embodiment of the present invention will be described. The configuration of the sound quality evaluation unit 12 in the sound quality evaluation apparatus 1 is different from that of the first embodiment. FIG. 12 is a block diagram showing a configuration example of the sound quality evaluation unit 12 in the sound quality evaluation device 1 according to the fourth embodiment. In the example shown in FIG. 12, the sound quality evaluation unit 12 includes level measurement units 128-1 and 128-2 and a correlation coefficient calculation unit 129.

The level measuring unit 128-1 measures the level of the reference audio signal a plurality of times at predetermined time intervals, and outputs the level of the plurality of times to the correlation coefficient calculating unit 129.

The level measuring unit 128-2 measures the level of the synchronized speech signal to be evaluated a plurality of times at predetermined time intervals, and outputs the plurality of levels to the correlation coefficient calculating unit 129.

The correlation coefficient calculation unit 129 moves one of the level input from the level measurement unit 128-1 and the level input from the level measurement unit 128-2 in the time direction (while shifting on the time axis) while Calculate a plurality of correlation coefficients of. The correlation coefficient between the level x _i input from the level measurement unit 128-1 and the level y _i input from the level measurement unit 128-2 is represented by the above equation (1).

Then, the correlation coefficient calculation unit 129 outputs the value indicating the maximum value of the correlation coefficient r among the calculated plurality of correlation coefficients to the outside as the sound quality evaluation index. Here, the value indicating the magnitude of the correlation coefficient r may be the value itself of the correlation coefficient r, or may be an evaluation value shown in multiple stages based on the correlation coefficient r. When outputting the evaluation value, the correlation coefficient calculation unit 129 determines the evaluation value in seven levels as shown in Table 1 according to the magnitude of the correlation coefficient r, for example. The larger the correlation coefficient r, the better the evaluation value.

FIG. 13 is a diagram for explaining the processing of the sound quality evaluation unit 12 of this embodiment. In the example shown in FIG. 13, the level of each of the reference voice signal and the synchronized voice signal to be evaluated is measured every 0.01 seconds for 0 to 60 seconds (FIG. 13A), and the measured level is 0. They are shifted by 0.01 seconds each (FIG. 13B). Then, the correlation coefficient is calculated for each shift. 21 correlation coefficients are obtained by shifting at intervals of 0.01 seconds from +0.1 seconds to −0.1 seconds (FIG. 13(c)). Finally, the maximum correlation coefficient is adopted from the 21 correlation coefficients. For example, as shown in FIG. 13C, when the correlation coefficient is 0.9 and is maximum when the delay time is −0.09 seconds, the sound quality evaluation index is set to the correlation coefficient r=0.9. The value is based on.

Next, a sound quality evaluation method in the sound quality evaluation apparatus 1 according to the fourth embodiment of the present invention will be described. FIG. 14 is a flowchart showing a sound quality evaluation method in the sound quality evaluation apparatus 1 according to the fourth embodiment of the present invention.

In step S401, the evaluated audio signal is synchronized with the reference audio signal. For example, the delay control unit 11 performs this process.

In step S402, the levels of the reference audio signal and the synchronous evaluated audio signal are measured. For example, this processing is performed by the level measuring units 128-1 and 128-2.

In step S403, one of the measured levels of the reference voice signal and the synchronized voice signal to be evaluated is moved in the time direction. That is, one measurement time is delayed. For example, the level measuring units 128-1 and 128-2 or the correlation coefficient calculating unit 129 performs this processing.

In step S404, the correlation coefficient of the levels of the reference voice signal and the synchronized voice signal to be evaluated is calculated each time the movement is performed in step S403, and the maximum correlation coefficient among them is adopted. For example, the correlation coefficient calculation unit 129 performs this process.

In step S405, a value indicating the magnitude of the correlation coefficient adopted in step S404 is output. For example, the correlation coefficient calculation unit 129 performs this process.

As described above, in the fourth embodiment, the level of the reference voice signal and the level of the synchronized voice signal to be evaluated are measured, the correlation coefficient is calculated while moving one in the time direction, and the maximum phase relationship is obtained. A value indicating the size of the number is output as the sound quality evaluation index. Therefore, the level of the instantaneous value can be calculated and compared, and the voice evaluation can be accurately performed.

Although the above embodiments have been described as representative examples, it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, it is possible to combine a plurality of constituent blocks or steps described in the embodiment into one or to divide one constituent block or step.

INDUSTRIAL APPLICABILITY The present invention is useful for sound quality evaluation of AM/FM radio, training thereof, and the like.

1 sound quality evaluation device 11 delay control unit 12 sound quality evaluation unit 121 noise addition unit 122 noise amount adjustment unit 123 silence determination unit 124, 128-1, 128-2 level measuring unit 125-1, 125-2 Fourier transform processing unit 126, 129 Correlation coefficient calculation unit 127 Silence frequency level measurement unit

Claims (4)

A sound quality evaluation device for evaluating the sound quality of an evaluated audio signal using a reference audio signal,
A delay control unit for delaying the evaluated audio signal and outputting a synchronized evaluated audio signal synchronized with the reference audio signal,
A sound quality evaluation unit that adds noise to the reference sound signal so as to approach the synchronized evaluated sound signal, and outputs a value indicating the magnitude of the noise as a sound quality evaluation index,
A sound quality evaluation apparatus comprising: A sound quality evaluation device for evaluating the sound quality of an evaluated audio signal using a reference audio signal,
A delay control unit for delaying the evaluated audio signal and outputting a synchronized evaluated audio signal synchronized with the reference audio signal,
When the level of pre-Symbol reference speech signal is equal to or less than the first threshold value, among the synchronization to be evaluated audio signal, the level of the voice band that is not used to measure the sound value that indicates the magnitude of the level A sound quality evaluation unit that outputs as a quality evaluation index ,
Features and to Ruoto quality evaluation apparatus that comprises a. A sound quality evaluation device for evaluating the sound quality of an evaluated audio signal using a reference audio signal,
A delay control unit for delaying the evaluated audio signal and outputting a synchronized evaluated audio signal synchronized with the reference audio signal,
When the level of the reference voice signal becomes equal to or lower than a first threshold value, the level of the unused voice band of the synchronized voice signal under evaluation is measured, and the level of the measured voice signal under synchronization is measured. If the difference between the maximum value and the average value or minimum value of the level exceeds a second threshold value, a sound quality evaluation unit that determines that an interference wave is superimposed on the synchronous evaluated audio signal,
Features and to Ruoto quality evaluation apparatus that comprises a. A sound quality evaluation apparatus for evaluating the sound quality of an evaluated audio signal using a reference audio signal,
A delay control unit for delaying the evaluated audio signal and outputting a synchronized evaluated audio signal synchronized with the reference audio signal,
The level of level and the synchronization evaluation target speech signal before Symbol reference speech signal is measured, the correlation coefficient while moving the one in the time direction, the sound quality evaluation values indicating the magnitude of the correlation coefficient becomes maximum A sound quality evaluation unit that outputs as an index ,
Features and to Ruoto quality evaluation apparatus that comprises a.

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