Sound output control device and sound output control method

Abstract

To control a sound output which sufficiently fulfills not only perception property but also functionality even when peripheral noise exists.SOLUTION: A sound output control device 1 for outputting warning sound to call attention of a user crewing in a vehicle includes a sound determination section 24 for determining the warning sound which fulfills predetermined functionality even with in-vehicle noise in the vehicle. The sound determination section 24 determines a sound volume or frequency of the warning sound based on an index F(x) having correlation with a subjective evaluation of the functionality which has to be achieved by the warning sound.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an audio output control device and an audio output control method. [Background technology]

[0002] Conventionally, in audio systems installed in vehicles, etc., there is a technology that performs volume compensation for the amount masked by noise on an audio signal corrected by dynamic loudness compensation based on the amount of noise collected by a microphone installed in the vehicle (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-160896 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 above increases the volume in response to noise, improving ease of hearing, i.e., perceptibility. However, for example, in the case of a warning sound for a railway vehicle, it is necessary to generate a sound that not only satisfies the perceptibility of being sufficiently audible, but also has sufficient functionality, such as being able to strongly call attention or wake up.

[0005] Therefore, the present invention aims to solve the above problem, that is, to provide an audio output control device and an audio output control method that can control the output of audio that satisfies not only perceptibility but also functionality, even when ambient noise is present. [Means for solving the problem]

[0006] An audio output control device according to one aspect of the present invention is an audio output control device that outputs an alarm sound to alert users in a vehicle, and has an audio determination unit that determines an alarm sound that satisfies a predetermined functionality even in the case of noise inside the vehicle, and is characterized in that the audio determination unit determines the volume or frequency of the alarm sound based on an index F that correlates with a subjective evaluation of the functionality that the alarm sound should fulfill.

[0007] An audio output control method according to one aspect of the present invention is an audio output control method for an audio output control device that outputs an alarm sound to alert users in a vehicle, and is characterized in that when determining an alarm sound that satisfies a predetermined functionality, even for noise inside the vehicle, the volume or frequency of the alarm sound is determined based on an index F that correlates with a subjective evaluation of the functionality that the alarm sound should fulfill. [Effects of the Invention]

[0008] According to the present invention, it is possible to control the output of audio that satisfies not only perceptibility but also functionality. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a functional block diagram showing the functional configuration of the audio output control device 1. As shown in FIG. [Figure 2] FIG. 2 is a diagram showing the relationship between the volume of the interior noise and the volume of the warning sound that satisfies functionality and perceptibility. [Figure 3] FIG. 3 is a diagram showing the frequency distribution of the warning sound and the noise inside the vehicle. [Figure 4] FIG. 4 is a diagram showing the relationship between the index F(x) and the subjective evaluation. [Figure 5] FIG. 5 is a flowchart of the alarm sound output process. [Figure 6] FIG. 6 is a diagram showing an example of a conversion table. [Figure 7] FIG. 7 is a diagram showing the relationship between the frequency of the alarm sound and the volume that satisfies the functionality. [Figure 8] FIG. 8 is a flowchart of another alarm sound output process. [Figure 9] FIG. 9 is a diagram showing the relationship between the volume of an alarm sound that satisfies the functionality and the drowsiness of the user. [Figure 10] FIG. 10 is a flowchart of another alarm sound output process. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First embodiment] The audio output control device and audio output control method will be described below with reference to the drawings.

[0011] (Functional configuration of audio output control device 1) 1 is a functional block diagram showing the functional configuration of the audio output control device 1. Here, an example will be described in which an alarm sound is output to alert crew members (hereinafter referred to as users as appropriate) such as drivers who are on duty in railway vehicles.

[0012] The audio output control device 1 is configured to have the functions of an operation input unit 11, an external state acquisition unit 12, a user state acquisition unit 13, an in-vehicle noise acquisition unit 14, a memory unit 15, a control unit 16, and an audio output unit 17. Here, the audio output control device 1 will be described as having all of the above-mentioned functions, but these functions may be configured by multiple devices, each of which may be capable of sending and receiving information, or the audio output control device 1 may include other functions.

[0013] The operation input unit 11 includes input devices such as a keyboard, a mouse, a touch panel, a microphone, and a reader or image input device for an external storage device. The operation input unit 11 receives operation input from a user, information stored in the memory unit 15, or information required for processing by the control unit 16, and supplies the information to the control unit 16.

[0014] The external condition acquisition unit 12 acquires the external condition for determining whether a condition requires an alarm or a warning required for railway operation, and supplies the acquired external condition to the control unit 16. The external condition acquisition unit 12 may be configured to include an imaging device or a sensor for detecting a dangerous condition, or may acquire information for detecting a dangerous condition acquired by another device.

[0015] The user state acquisition unit 13 acquires information necessary to detect the user's state and supplies it to the control unit 16. The user state acquisition unit 13 is configured, for example, with an imaging device such as a camera, or an input device that acquires image data captured by an external imaging device. In this case, the user state acquisition unit 13 acquires the captured user's state and supplies it to the control unit 16. The user state acquisition unit 13 is, for example, a wearable device that measures the user's biometric information. In this case, the user state acquisition unit 13 acquires biometric information such as the user's pulse, blood pressure, and respiratory rate and supplies it to the control unit 16. The information necessary to detect the user's state acquired by the user state acquisition unit 13 may be of multiple types.

[0016] The interior noise acquisition unit 14 is, for example, composed of a microphone, or has the function of acquiring audio information picked up by an external microphone. The interior noise acquisition unit 14 acquires interior noise such as noise from the driver's cab caused by the running sound of the railway vehicle, and supplies the acquired noise to the control unit 16.

[0017] The storage unit 15 is configured to have, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), and a non-volatile memory. The storage unit 15 stores information related to alarm sounds. A plurality of alarm sounds to be output may be stored, and the operation input unit 11 can set which alarm sound to use depending on, for example, the route on which the railway vehicle runs, the content of the alarm or warning, or the selection or setting by the occupant receiving the alarm.

[0018] (Control unit) The control unit 16 is composed of a CPU (Central Processing Unit), a storage unit (ROM (Read Only Memory), RAM (Random Access Memory), non-volatile memory, etc.), and other elements including hardware. The control unit 16 executes a control application program (not shown) stored in the storage unit 15 to control the entire audio output control device 1 and also functions as a user state determination unit 21 to an audio output control unit 25.

[0019] The control unit 16 executes an alarm sound output process (described later) for outputting an alarm sound that satisfies predetermined functionality even when there is noise inside the vehicle.

[0020] ((principle)) (((Alarm sound that meets functionality))) An alarm sound that satisfies functionality is an alarm sound that can wake up a user, for example, by making the user who hears it feel as if they have woken up.

[0021] (((Relationship between the volume of the alarm sound that satisfies functionality and the volume of the alarm sound that satisfies perceptibility))) Figure 2 is a diagram showing the relationship between the volume of interior noise and the volume of an alarm sound that satisfies functionality and the volume of an alarm sound that can be clearly heard by the user (hereinafter referred to as an alarm sound that satisfies perceptibility). The line Sp shows the relationship between the volume of interior noise and the volume of an alarm sound that satisfies perceptibility. The line Sf shows the relationship between the volume of interior noise and the volume of an alarm sound that satisfies functionality. The tone of the alarm sounds is the same in both cases.

[0022] As shown by the line Sp, as the volume of the interior noise increases, the volume that satisfies perceptibility also increases. Furthermore, as shown by the line Sf, as the volume of the interior noise increases, the volume that satisfies functionality also increases. However, for the same interior noise, the volume that satisfies perceptibility and the volume that satisfies functionality are different, and the volume that satisfies functionality is greater than the volume that satisfies perceptibility. Therefore, even if the volume of the warning sound satisfies perceptibility, it may not always satisfy functionality. In other words, even if the user can hear the warning sound, it may not wake them up.

[0023] (((Indicator F(x) based on the frequency distribution of interior noise and warning sounds))) FIG. 3 shows the frequency distributions of warning sounds SG1, SG2, and SG3 (hereinafter, simply referred to as warning sounds SG when there is no need to distinguish between them individually), which are signal sounds with a predetermined beeping tone and have the same volume of 75 dB but different frequencies, as well as the frequency distribution of interior noise NS1, which has a volume of 75 dB. The frequencies of the warning sounds SG increase in the order of warning sounds SG1, SG2, and SG3. The horizontal axis represents the center frequency of the 1 / 3 octave band, and the vertical axis represents the sound pressure level. In other words, FIG. 3 shows the result of 1 / 3 octave analysis. As shown in FIG. 3, interior noise NS1 is mainly composed of low-frequency sounds, while warning sound SG is mainly composed of high-frequency sounds. Therefore, at high frequencies, the sound pressure level of warning sound SG tends to be higher than the sound pressure level of interior noise NS1. In the figure, the up and down arrows between the warning sound SG1 and the interior noise NS1 indicate the portion where the sound pressure level of the warning sound SG1 exceeds the sound pressure level of the interior noise NS1.

[0024] The magnitude of the portion where the sound pressure level of the warning sound SG exceeds the sound pressure level of the interior noise NS1 can be calculated using equation (1). Equation (1) is the sum of the differences obtained by subtracting the sound pressure level of the interior noise from the sound pressure level of the warning sound for each predetermined frequency band in the results of frequency analysis of the warning sound and the results of frequency analysis of the interior noise, weighted by 100 times in the frequency band of 2000 Hz to 200,000 Hz. This F(x) will be referred to as the index F(x) below. Furthermore, if the value obtained by subtracting the sound pressure level of the interior noise from the sound pressure level of the warning sound is negative, the difference is set to zero.

number

[0025] 3, the index F(x) of the warning sounds SG1, SG2, and SG3 increases in that order, i.e., the higher the frequency, the larger the index F(x).

[0026] (((Correlation between index F(x) and subjective evaluation of functionality))) Fig. 4 is a diagram showing the relationship between the index F(x) and the subjective evaluation of functionality. The plot in Fig. 4 shows the correspondence between the index F(x) and the subjective evaluation of functionality for combinations of the warning sounds SG1, SG2, and SG3 (all of which have a volume of 75 dB) shown in Fig. 3 and multiple interior noises NS1 of different volumes shown in Fig. 3.

[0027] The subjective evaluation of functionality was conducted by having experienced train drivers listen to combinations of warning sounds SG1, SG2, and SG3 with interior noise NS1 at different volumes, and then classifying the sounds in terms of alertness on a scale of 1 to 7. For example, a combination that gave the impression of being slightly waking up was rated level 5, and a combination that gave the impression of being very waking up was rated level 7.

[0028] The relationship between the index F(x) and the subjective evaluation of functionality shown in Figure 4 indicates a high correlation coefficient between the index F(x) and the subjective evaluation. In other words, combinations with a high index F(x) also have a high subjective evaluation value (also called the subjective evaluation level) of functionality.

[0029] The right side of Fig. 4 shows the circled plots on the left side of Fig. 4 for each volume of interior noise NS1. For example, at volume Vn1 of interior noise NS1, the subjective assessment values ​​are greatest for warning sounds SG1, SG2, and SG3 in that order. This is the same order as the magnitude of the index F(x) values, as shown in Fig. 3. This also shows that there is a correlation between index F(x) and subjective assessment, with the higher the frequency, the higher the subjective assessment value.

[0030] In the example of Fig. 3, the warning sound SG and the interior noise NS1 are at the same volume, but if the volume of the warning sound SG increases, the frequency distribution shown in Fig. 3 moves upward in the figure, and the value of the index F(x) increases. In other words, since the index F(x) and the subjective evaluation are correlated, the louder the volume, the higher the subjective evaluation value.

[0031] (((Use of index F(x)))) As described above, the index F(x) correlates with the subjective evaluation of functionality. Therefore, the control unit 16 outputs an alarm sound at a volume that can obtain the index F(x) corresponding to the required subjective evaluation level, so that the functionality is perceived at that required subjective evaluation level. In other words, the control unit 16 can output an alarm sound that satisfies the predetermined functionality even when interior noise is present. Note that, as shown in FIG. 2, for the same interior noise, the volume of an alarm sound that satisfies functionality is greater than the volume of an alarm sound that satisfies perceptibility, so an alarm sound that satisfies functionality satisfies perceptibility.

[0032] ((Controller Function)) Returning to FIG. 1, the user state determination unit 21 to the audio output control unit 25 of the control unit 16 will be described.

[0033] The user state determination unit 21 determines whether or not a state requires the issuance of an alarm based on the user state information supplied from the user state acquisition unit 13, and supplies the determination result to the audio output execution determination unit 23. Here, the user state determination unit 21 will be described as determining the level of drowsiness (wakefulness level) of the user based on the user state information supplied from the user state acquisition unit 13. Specifically, the user state determination unit 21 can determine the level of drowsiness of the user by, for example, detecting the size of the user's pupils from image data of the user's face supplied from the user state acquisition unit 13, or by acquiring biological information of the user such as the pulse rate, blood pressure, and respiratory rate supplied from the user state acquisition unit 13. The method of determining the level of drowsiness of the user by the user state determination unit 21 is not limited to this method.

[0034] The external state determination unit 22 determines whether or not a state requires the output of some kind of alarm sound or the like based on the external state information supplied from the external state acquisition unit 12, and supplies the determination result to the audio output execution determination unit 23. For example, the external state determination unit 22 acquires image information of the front of the vehicle and detection results of various sensors from the external state acquisition unit 12, and detects an abnormal or dangerous state, or determines whether or not a signal indicating that an abnormal or dangerous state has been detected has been input from an external device.

[0035] The audio output execution determination unit 23 determines whether to output an alarm sound based on various setting information input by the operation input unit 11, the user state determination result by the user state determination unit 21, and the external state determination result by the external state determination unit 22. When determining that an alarm sound should be output, the audio output execution determination unit 23 supplies the determination result to the audio determination unit 24.

[0036] When the sound determination unit 24 receives the determination result that an alarm sound should be output from the sound output execution determination unit 23, the sound determination unit 24 determines the volume of the alarm sound based on an index F(x) that has a correlation with a subjective evaluation of the functionality that the alarm sound should fulfill. A specific method for determining this will be described later.

[0037] The audio output control unit 25 outputs the alarm sound at the volume determined by the audio determination unit 24 to the outside via the audio output unit 17. The audio output unit 17 is configured by an audio output device such as a speaker, or is configured to have a function of outputting audio data to an external audio output device.

[0038] (Alarm sound output processing) The alarm sound output process executed by the audio output control device 1 will be described with reference to the flowchart of FIG.

[0039] In step S11, the sound determination unit 24 determines a subjective evaluation level for the required alarm sound. For example, the subjective evaluation level is determined depending on the purpose of the alarm sound, and is designated by the user.

[0040] Next, in step S12, the sound determination unit 24 determines an index F(x) (hereinafter referred to as a target index value) corresponding to the determined subjective assessment level. In this example, a correspondence relationship between the index F(x) based on a predetermined model of interior noise when a vehicle is running and a signal sound of a predetermined tone that sounds like a "beep beep" and warning sounds of different volumes, and the subjective assessment level (see FIG. 4) has been determined in advance, and a correspondence table shown in FIG. 6 indicating this correspondence relationship is stored in the storage unit 15. The sound determination unit 24 determines the index F(x) corresponding to the determined subjective assessment level by referring to the conversion table.

[0041] In step S13, the user status acquisition unit 13 starts acquiring the user status. When the user status acquisition unit 13 starts acquiring the user status, the user status determination unit 21 of the control unit 16 determines the user status based on the user status information supplied from the user status acquisition unit 13, and supplies the determination result to the voice output execution determination unit 23.

[0042] In step S14, the external state acquisition unit 12 starts acquiring the external state to determine whether or not a state requires an alarm or a warning required for railway operation. When the external state acquisition unit 12 starts acquiring the external state, the external state determination unit 22 determines whether or not a state requires the output of some kind of alarm sound, etc., based on the external state information supplied from the external state acquisition unit 12, and supplies the determination result to the audio output execution determination unit 23.

[0043] In step S15, the audio output execution determination unit 23 determines whether or not an alarm sound needs to be output based on various setting information input by the operation input unit 11, the user state determination result by the user state determination unit 21, and the external state determination result by the external state determination unit 22.

[0044] If it is determined in step S15 that an alarm sound needs to be output, in step S16 the audio output execution determination unit 23 supplies the determination result to the audio determination unit 24. The audio determination unit 24 causes the interior noise acquisition unit 14 to start acquiring interior noise, and acquires the interior noise from the interior noise acquisition unit 14. Then, based on the acquired interior noise and alarm sound, the audio determination unit 24 determines a volume that satisfies the target index value determined in step S12 as the volume of the alarm sound.

[0045] Specifically, the sound determination unit 24 performs a frequency analysis on the obtained interior noise. The sound determination unit 24 then calculates an index F(x) by using formula (1) based on the frequency analysis results of the interior noise and the frequency analysis results of each of the warning sounds with different volumes at a predetermined frequency. The sound determination unit 24 then determines the volume of the warning sound to be output as the volume of the warning sound for which, among the calculated indexes F(x), an index F(x) that is equal to or greater than the target index value determined in step S12 and closest to the target index value is obtained. Note that sound pressures in predetermined frequency units can be stored in the storage unit 15 as a conversion table as the frequency analysis results for each of the warning sounds with different volumes. The sound determination unit 24 obtains from the storage unit 15 the conversion tables as the frequency analysis results for each of the warning sounds with the same frequency but different volumes, and calculates formula (1) to calculate the index F(x).

[0046] Next, in step S17, the audio output control unit 25 outputs an alarm sound to the outside at the volume determined in step S16 via the audio output unit 17. Thereafter, the process ends.

[0047] In this way, the alarm sound output process determines the volume of the alarm sound based on the index F(x), which is correlated with the subjective evaluation of the functionality that the alarm sound should fulfill, and outputs the alarm sound at that volume, so that it is possible to output an alarm sound that fully satisfies not only perceptibility but also functionality.

[0048] [Second embodiment: another example of alarm sound output processing] (Relationship between volume and frequency to satisfy functionality for interior noise) Figure 7 shows the relationship between the frequency of an alarm sound and the volume that satisfies functionality. Figure 7 shows the volume that satisfies functionality for two alarm sounds that have the same tone but different frequencies. The line Sf-1 shows the volume that satisfies functionality for an alarm sound with frequency F31. The line Sf-2 shows the volume that satisfies functionality for an alarm sound with frequency F41, which is higher than frequency F31.

[0049] In the first embodiment, a volume that satisfies the functionality of the subjective evaluation level is determined based on the correspondence between the warning sounds, which are signal sounds of a predetermined tone that sound like "beep beep" but have the same frequency but different volume levels, the index F(x) based on the noise inside the vehicle, and the subjective evaluation level, and the warning sound is output at that volume. However, depending on the performance of the speaker serving as the audio output unit 17, it may not be possible to output the warning sound at the determined volume. In such cases, the phenomenon shown in FIG. 7 can be utilized to adjust the frequency of the warning sound, thereby outputting a warning sound that satisfies the functionality.

[0050] 7, for example, when the interior noise is at volume Vn11, an alarm sound of frequency F31 needs to be output at volume Vs11 to satisfy the required subjective assessment level. However, if the maximum output volume VL of the speaker serving as audio output unit 17 is lower than volume Vs11, the alarm sound cannot be output at volume Vs11. On the other hand, in the case of frequency F41, which is higher than frequency F31, the volume Vs12 required to satisfy the required subjective assessment level is lower than maximum output volume VL, so the alarm sound can be output at volume Vs12. In other words, an alarm sound that satisfies the functionality of the subjective assessment level can be output.

[0051] FIG. 8 is a flowchart of an alarm sound output process that utilizes this principle.

[0052] In steps S31 to S36 and S38, the same processing as in steps S11 to S17 in FIG. 5 is executed, and therefore a description thereof will be omitted.

[0053] In step S37, the sound determination unit 24 determines whether the sound volume determined in step S36 is equal to or greater than the maximum output sound volume of the speaker serving as the sound output unit 17. If it is determined that the sound volume determined in step S36 is equal to or greater than the maximum output sound volume of the speaker serving as the sound output unit 17, in step S39 the sound determination unit 24 sets the sound volume of the warning sound to be output as a sound volume that is equal to or less than the maximum output sound volume of the speaker serving as the sound output unit 17 and that satisfies the target index value for a warning sound with a frequency higher than the frequency of the warning sound when the sound volume was determined.

[0054] Specifically, the sound determination unit 24 calculates the index F(x) by calculating formula (1) based on the frequency analysis result of the interior noise and the frequency analysis result of the warning sound whose volume is lower than the volume determined in step S36 and whose frequency is higher than the frequency when the volume was determined in step S36. Then, the sound determination unit 24 determines, as the volume of the warning sound to be output, the volume of the warning sound for which, among the calculated indexes F(x), an index F(x) has been obtained that is equal to or greater than the target index value determined in step S32 and is closest to the target index value.

[0055] In this way, when the alarm sound output process determines the volume of the alarm sound based on the index F(x) which has a correlation with the subjective evaluation of the functionality that the alarm sound should fulfill, if the determined volume exceeds the maximum output volume of the speaker serving as audio output unit 17, the volume of the alarm sound is set to the volume at which the determined index F(x) can be obtained from an alarm sound of a higher frequency.Therefore, even if there are limitations in the performance of the speaker serving as audio output unit 17, an alarm sound that fully satisfies not only perceptibility but also functionality can be output.

[0056] [Third embodiment: Example of volume adjustment according to user state] (Relationship between user status and alarm volume)

[0057] 9 is a diagram showing the relationship between the volume of the alarm sound that satisfies the functionality and the drowsiness of the user. As can be seen, the stronger the drowsiness of the user, the higher the volume that satisfies the functionality.

[0058] In the first embodiment, for example, the subjective assessment level is determined based on the purpose of the alarm sound, and the volume of the alarm sound is determined based on the index F(x) corresponding to the subjective assessment level. However, depending on the state of the user, even the determined volume may not satisfy the functionality of the subjective assessment level. In such cases, an alarm sound that satisfies the functionality can be output by adjusting the volume depending on the state of the user.

[0059] FIG. 10 is a flowchart of an alarm sound output process that utilizes this principle.

[0060] In steps S41 to S46 and S48, the same processing as in steps S11 to S17 in FIG. 5 is executed, and therefore a description thereof will be omitted.

[0061] In step S47, the audio determination unit 24 determines whether the intensity of the user's drowsiness determined by the user state determination unit 21 is stronger than the user's drowsiness assumed when the volume was determined in step S46, and if it is determined to be stronger, in step S49, adjusts the volume to correspond to the drowsiness determined by the user state determination unit 21.

[0062] The correspondence table in FIG. 6 is based on the subjective evaluation level for the intensity of the user's drowsiness, and when the intensity of the user's drowsiness determined by the user state determination unit 21 is stronger than the predetermined drowsiness level, the audio determination unit 24 increases the volume determined in step S46 by an amount corresponding to the intensity of the user's drowsiness determined by the user state determination unit 21.

[0063] In this way, when the volume of the alarm sound is determined by the alarm sound output process based on the index F(x) that correlates with the subjective evaluation of the functionality that the alarm sound should fulfill, the determined volume is adjusted in accordance with the user's condition, so that an alarm sound that fully satisfies not only perceptibility but also functionality can be output in accordance with the user's condition.

[0064] [Fourth embodiment: Index F(x) based on loudness value] In the above, as shown in FIG. 3, F(x) indicating the volume of the sound portion of the warning sound SG where the sound pressure is higher than the in-vehicle noise NS1 is used as the index, but other characteristics can also be used as the index.

[0065] The difference between the result of loudness analysis of the composite sound of the interior noise and the warning sound (first loudness value) and the result of loudness analysis of the interior noise (second loudness value), obtained by equation (2), can be used as an index F(x). This index F(x) and the subjective assessment level are correlated. That is, the sound determination unit 24 can determine the volume of the warning sound at which the index F(x) corresponding to the determined subjective assessment level can be obtained, and use this as the volume of the warning sound. F(x) = (first loudness value) - (second loudness value) (2)

[0066] By this processing, the volume of the warning sound is determined based on the loudness value of the composite sound of the interior noise and the warning sound and an index value based on the loudness value of the interior noise, and the warning sound is output at that volume, so that a warning sound that satisfies not only perceptibility but also functionality can be output.

[0067] [Variations] In the above-described embodiment, the subjective evaluation level is determined depending on the purpose of the warning sound, etc., and is specified by the user (steps S11, S31, S41). However, the subjective evaluation level can also be changed based on external state information acquired by the external state acquisition unit 12, user state information acquired by the user state acquisition unit 13, in-vehicle noise acquired by the in-vehicle noise acquisition unit 14, etc.

[0068] [Supplementary explanation of the embodiment] The above-described embodiments each show a preferred specific example of the present invention. The numerical values, components, arrangement positions and connection order of components, processing order in flowcharts, etc. shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, each figure is not necessarily a strict illustration.

[0069] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0070] The above-described series of processes can be executed by hardware or software. When the series of processes is executed by software, the program constituting the software is installed from a program recording medium into a computer incorporated in dedicated hardware, or into, for example, a general-purpose personal computer that can execute various functions by installing various programs.

[0071] The program executed by the computer may be a program that processes in chronological order according to the order described in this specification, or may be a program that processes in parallel or at the required timing, such as when called.

[0072] [Note] The contents of the above-described embodiments can be understood, for example, as follows. (1) The above-described audio output control device 1 is In a voice output control device 1 that outputs an alarm sound to alert a user who is driving a vehicle, For vehicle interior noise, the sound determination unit 24 determines an alarm sound that satisfies a predetermined functionality, and determines the volume or frequency of the alarm sound based on an index F(x) (FIGS. 4 and 6) that correlates with a subjective evaluation of the functionality that the alarm sound should fulfill.

[0073] In this way, the volume or frequency of the alarm sound is determined based on the index F(x) (Figs. 4 and 6) which correlates with the subjective evaluation of the functionality that the alarm sound should fulfill, so that an alarm sound that satisfies not only perceptibility but also functionality can be output.

[0074] (2) The index F(x) is the weighted sum of the sum of the differences for each frequency. The index F(x) is a weighted sum of the differences obtained by subtracting the sound pressure level of the interior noise from the sound pressure level of the warning sound for each predetermined frequency band in the results of the frequency analysis of the warning sound and the results of the frequency analysis of the interior noise, in a predetermined high-frequency band.

[0075] The index F(x) is the sum of the differences obtained by subtracting the sound pressure level of the interior noise from the sound pressure level of the warning sound for each of a plurality of frequency bands in the results of the frequency analysis of the warning sound and the results of the frequency analysis of the interior noise, and weighting this summation on a predetermined high-frequency band. Since this index F(x) correlates with the subjective evaluation of the functionality that the sound should fulfill, by determining the volume or frequency of the warning sound based on the index F(x), it is possible to output a warning sound that satisfies not only perceptibility but also functionality.

[0076] (3) Loudness comparison The index F(x) is a value obtained by subtracting the second loudness value of the interior vehicle noise from the first loudness value of the composite sound of the warning sound and the interior vehicle noise.

[0077] The index F(x), which is the value obtained by subtracting the second loudness value of the interior noise from the first loudness value of the composite sound of the warning sound and the interior noise, correlates with the subjective evaluation of the functionality that the sound should fulfill. Therefore, by determining the volume or frequency of the warning sound based on the index F(x), it is possible to output a warning sound that satisfies not only perceptibility but also functionality.

[0078] (4) Frequency adjustment When the determined first volume is greater than a predetermined threshold, the sound determination unit 24 determines the volume of the warning sound to be a second volume that is equal to or less than the predetermined threshold and that can obtain a predetermined index value corresponding to a subjective evaluation based on a warning sound of a second frequency that is higher than the first frequency of the warning sound when the first volume was determined.

[0079] An alarm sound with a high frequency can satisfy the subjective evaluation level at a lower volume (Fig. 7). Therefore, when the volume of the alarm sound determined based on the index F(x) exceeds the maximum output volume of the speaker, this principle is used to determine the frequency of the alarm sound that satisfies the specified functionality even if the volume is below the maximum output volume, and an alarm sound of that frequency is output. Therefore, an alarm sound that satisfies not only perceptibility but also functionality can be output at a volume below the maximum output volume.

[0080] (5) Adjustment according to the user's condition The audio determination unit 24 can adjust the determined volume based on the state of the user.

[0081] The more drowsy the user, the higher the volume that satisfies functionality. Therefore, the volume of the determined alarm sound can be adjusted based on the user's state, so that an alarm sound that satisfies not only perceptibility but also functionality can be output in accordance with the user's state. [Explanation of symbols]

[0082] 1...Audio output control device, 11...Operation input unit, 12...External state acquisition unit, 13...User state acquisition unit, 14...In-vehicle noise acquisition unit, 15...Storage unit, 16...Control unit, 17...Audio output unit, 21...User state determination unit, 22...External state determination unit, 23...Audio output execution determination unit, 24...Audio determination unit, 25...Audio output control unit

Claims

1. In a voice output control device that outputs an alarm sound to alert a user who is driving a vehicle, The vehicle also has a sound determination unit that determines the warning sound that satisfies a predetermined functionality, and the sound determination unit determines the volume or frequency of the warning sound based on an index that has a correlation with a subjective evaluation of the functionality that the warning sound should fulfill.

10. An audio output control device comprising:

2. 2. The audio output control device according to claim 1, The index is a sum of the differences obtained by subtracting the sound pressure level of the interior noise from the sound pressure level of the warning sound for each of a plurality of predetermined frequency bands in the frequency analysis result of the warning sound and the frequency analysis result of the interior noise, and weighting the sum of the differences in a predetermined high-frequency band.

10. An audio output control device comprising:

3. 2. The audio output control device according to claim 1, The index is a value obtained by subtracting a second loudness value of the interior vehicle noise from a first loudness value of a composite sound of the warning sound and the interior vehicle noise.

10. An audio output control device comprising:

4. 2. The audio output control device according to claim 1, When the determined first volume is greater than a predetermined threshold, the sound determination unit determines, as the volume of the warning sound, a second volume that is equal to or less than the predetermined threshold and that can obtain a predetermined index value corresponding to a subjective evaluation based on the warning sound having a second frequency that is higher than the first frequency of the warning sound when the first volume is determined.

10. An audio output control device comprising:

5. 2. The audio output control device according to claim 1, The audio determination unit adjusts the determined volume based on the state of the user.

10. An audio output control device comprising:

6. 1. A voice output control method for a voice output control device that outputs an alarm sound to alert a user who is driving a vehicle, When determining the alarm sound that satisfies a predetermined functionality for the interior noise of the vehicle, the volume or frequency of the alarm sound is determined based on an index that has a correlation with a subjective evaluation of the functionality that the alarm sound should fulfill.

10. A sound output control method comprising:

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