Vehicle proximity warning device, vehicle proximity warning method, and mobile device

Abstract

To provide a vehicle proximity notification device, etc., which can be adjusted in such a manner that sound of a sound source not adjusted in sound pressure beforehand, can output sound equal to or higher than a specific sound pressure at a specific frequency.SOLUTION: A vehicle proximity notification device 10 comprises: an acquisition unit acquiring a first audio signal for which a first frequency band of a first sound source signal is extracted and a second audio signal for which a second frequency band is extracted; a simulation signal processing unit 113 generating a simulation signal by performing simulation signal processing on a second sound source signal; a third filter unit 117 generating a third audio signal by extracting a first frequency band of the simulation signal; a fourth filter unit 118 generating a fourth audio signal by extracting a second frequency band of the simulation signal; a sound pressure adjustment unit 114 generating an audio signal for output by adjusting a sound pressure of the simulation signal in such a manner that a first differential between the first audio signal and the third audio signal and a second differential between the second audio signal and the fourth audio signal are reduced; and an output unit 120 outputting to a loudspeaker, the audio signal for output.SELECTED DRAWING: Figure 2

Description

Technical Field

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[0001] The present disclosure relates to a vehicle proximity notification device and a vehicle proximity notification method that are mounted on a vehicle and output an alarm sound for notifying the approach of the vehicle to the outside, and a mobile device including the vehicle proximity notification device.

Background Art

[0002] Since electric vehicles and hybrid vehicles are low-noise, there is a problem that pedestrians and the like are difficult to notice the approach of the vehicle during low-speed driving with low self-vehicle road noise. For this reason, low-noise vehicles such as electric vehicles and hybrid vehicles are equipped with a vehicle proximity notification device that warns pedestrians and the like of the approach of the vehicle by generating an alarm sound that is a continuous sound that reminds the driving state of the vehicle during driving (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a vehicle proximity notification device, it is required that a sound with a prescribed sound pressure be output at a prescribed frequency. When setting the sounds of various sound sources as the alarm sound, it is necessary to adjust so that a sound with a sound pressure equal to or higher than the prescribed sound pressure is output at the prescribed frequency for the sound of each sound source.

[0005] Therefore, the present disclosure provides a vehicle proximity notification device and the like that can adjust the sound of a sound source for which sound pressure adjustment has not been performed in advance so that a sound with a sound pressure equal to or higher than the prescribed sound pressure is output at the prescribed frequency.

Means for Solving the Problems

[0006] A vehicle proximity warning device according to one aspect of the present invention is a vehicle proximity warning device that notifies of the proximity of a vehicle by having a speaker located on the vehicle output a warning sound toward the outside of the vehicle, comprising: an acquisition unit that acquires a first audio signal from which the first frequency band of a first sound source signal is extracted, and which, after specific signal processing, is output by the speaker such that the sound pressure in the first frequency band is greater than a specified first sound pressure and the sound pressure in the second frequency band different from the first frequency band is greater than a specified second sound pressure; and a second audio signal from which the second frequency band of the first sound source signal is extracted; and the specific signal processing applied to the second sound source signal different from the first sound source signal. The system includes: a simulated signal processing unit that generates a simulated signal by performing simulated signal processing including signal processing to simulate the characteristics of the speaker; a third filter unit that generates a third audio signal by extracting the first frequency band of the simulated signal; a fourth filter unit that generates a fourth audio signal by extracting the second frequency band of the simulated signal; a sound pressure adjustment unit that generates an output audio signal by adjusting the sound pressure of the first frequency band of the simulated signal and the sound pressure of the second frequency band of the simulated signal so that the first difference between the first audio signal and the third audio signal and the second difference between the second audio signal and the fourth audio signal are small; and an output unit that outputs the output audio signal to the speaker.

[0007] These general or specific embodiments may be implemented as a system, method, integrated circuit, computer program, or recording medium such as a computer-readable CD-ROM, or as any combination of a system, method, integrated circuit, computer program, and recording medium. [Effects of the Invention]

[0008] The vehicle proximity warning device and the like of this disclosure can adjust the sound of a sound source that has not undergone prior sound pressure adjustment so that a specified sound pressure is output at a specified frequency. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram of a vehicle equipped with a vehicle proximity warning device according to an embodiment. [Figure 2] Figure 2 is a block diagram showing an example of the functional configuration of a vehicle proximity warning device according to an embodiment. [Figure 3] Figure 3 shows the sound pressure frequency characteristics of a speaker according to an embodiment. [Figure 4] Figure 4 shows an example of a simulated filter for simulated signal processing that simulates the sound pressure frequency characteristics of a speaker according to the embodiment. [Figure 5] Figure 5 is a flowchart showing an example of the operation of a vehicle proximity warning device according to an embodiment. [Figure 6] Figure 6 is a flowchart showing a specific example of sound pressure adjustment processing according to the embodiment. [Modes for carrying out the invention]

[0010] (Knowledge that forms the basis of this disclosure) Conventional vehicle proximity warning systems include a speaker that generates a warning sound, a sound source that outputs a signal corresponding to the warning sound, and an amplifier that amplifies the signal output from the sound source and outputs it to the speaker.

[0011] The vehicle alarm sound source described in Patent Document 1 comprises an external speaker, an internal speaker, a microphone installed at a location inside the vehicle where sound reduction is to be desired, and an adaptive controller. The vehicle alarm sound source generates a warning sound from the external speaker via an amplifier based on a reference signal. At this time, the adaptive controller identifies the inverse transfer characteristics with respect to the transfer characteristics of the internal spatial transmission system based on the input of the reference signal and the microphone, and controls the output sound of the internal speaker via the amplifier so that the microphone input is minimized.

[0012] Furthermore, the in-vehicle alarm sound device described in Patent Document 2 generates a control sound to control the directional characteristics of the alarm sound, and changes the directional characteristics of the alarm sound to desired characteristics through signal processing.

[0013] In this way, by emitting an alarm sound to the outside of the vehicle, it is possible to notify pedestrians and others of the vehicle's approach.

[0014] Furthermore, regarding warning sounds emitted from low-noise vehicles such as electric vehicles and hybrid vehicles, the North American NHTSA (National Highway Traffic Safety Administration) is considering regulations for minimum sound pressure levels. For example, minimum sound pressure levels are defined for eight frequency bands of one-third octave, and the warning sound must be emitted at or above this minimum sound pressure level when measured using a prescribed measurement method. Therefore, the sound pressure of the warning sound cannot be lowered below the minimum sound pressure level. Thus, there is a need for technology that can emit a warning sound at or above the minimum sound pressure level while reducing the discomfort caused to passengers.

[0015] In the conventional technology described above, when setting sounds from various sound sources as alarm sounds, it is necessary to check whether each sound source is outputting a sound above a specified sound pressure at a specified frequency, adjust the sound pressure, and then store the determined parameters for each sound source. Thus, sound pressure adjustment is required for each sound source, making the sound pressure adjustment process time-consuming. In addition, it is necessary to allocate storage space in the memory unit to store the determined parameters.

[0016] In order to solve the above problems, a vehicle proximity notification device according to a first aspect of the present disclosure is a vehicle proximity notification device that notifies the proximity of the vehicle by outputting an alarm sound toward the outside of the vehicle from a speaker disposed in the vehicle, and is a first sound source signal that, after being subjected to specific signal processing, when output from the speaker, has a sound pressure in a first frequency band greater than a prescribed first sound pressure and a sound pressure in a second frequency band different from the first frequency band greater than a prescribed second sound pressure. An acquisition unit that acquires a first audio signal from which a first frequency band of the first sound source signal is extracted, and a second audio signal from which the second frequency band of the first sound source signal is extracted; A simulation signal processing unit that generates a simulation signal by performing simulation signal processing including the specific signal processing and signal processing for simulating the characteristics of the speaker on a second sound source signal different from the first sound source signal; A third filter unit that generates a third audio signal by extracting the first frequency band of the simulation signal; A fourth filter unit that generates a fourth audio signal by extracting the second frequency band of the simulation signal; A sound pressure adjustment unit that generates an output audio signal by adjusting the sound pressure in the first frequency band and the sound pressure in the second frequency band of the simulation signal so that a first difference between the first audio signal and the third audio signal and a second difference between the second audio signal and the fourth audio signal are reduced; An output unit that outputs the output audio signal to the speaker.

[0017] According to this, a sound pressure adjustment process is performed on the simulation signal so that the sound pressure of each of the first frequency band and the second frequency band of the simulation signal obtained based on the second sound source signal for which sound pressure adjustment has not been performed in advance approaches the sound pressure of each of the first frequency band and the second frequency band in the first sound source signal for which sound pressure adjustment has been performed in advance. For this reason, even for an alarm sound based on the second sound source signal, the sound pressure in the first frequency band and the sound pressure in the second frequency band can be made closer to the sound based on the first sound source signal that has been adjusted in advance to satisfy the regulation. Therefore, it is possible to adjust the sound of a sound source for which sound pressure adjustment has not been performed in advance so that a sound having a sound pressure equal to or higher than a prescribed sound pressure is output at a prescribed frequency.

[0018] Further, the vehicle proximity notification device according to the second aspect of the present disclosure is the vehicle proximity notification device according to the first aspect, and further includes a first filter unit that generates the first audio signal by extracting the first frequency band of the first sound source signal, and a second filter unit that generates the second audio signal by extracting the second frequency band of the first sound source signal.

[0019] Therefore, the first audio signal and the second audio signal can be generated based on the first sound source signal. Thus, even without storing the first audio signal and the second audio signal, the generated first audio signal and second audio signal can be used for the sound pressure adjustment process by the sound pressure adjustment unit, so there is no need to secure the storage capacity of the storage device for storing the first audio signal and the second audio signal.

[0020] Further, the vehicle proximity notification device according to the third aspect of the present disclosure is the vehicle proximity notification device according to the first aspect or the second aspect, wherein the first frequency band is included in a low frequency band below a predetermined frequency, and the second frequency band is included in a high frequency band above the predetermined frequency.

[0021] Therefore, a sound that complies with the regulations can be generated based on the second sound source signal.

[0022] Further, the vehicle proximity notification device according to the fourth aspect of the present disclosure is the vehicle proximity notification device according to the third aspect, wherein the first frequency band and the second frequency band are non-adjacent frequency bands among a plurality of frequency bands divided every 1 / 3 octave.

[0023] Therefore, a sound that complies with the regulations can be generated based on the second sound source signal.

[0024] A fifth aspect of the present disclosure is a vehicle proximity notification method that notifies of the proximity of a vehicle by outputting an alarm sound from a speaker located outside the passenger compartment of the vehicle, comprising: a first audio signal obtained by extracting the first frequency band of a first sound source signal, which, after specific signal processing, is output by the speaker such that the sound pressure in a first frequency band is greater than a specified first sound pressure and the sound pressure in a second frequency band different from the first frequency band is greater than a specified second sound pressure; and a second audio signal obtained by extracting the second frequency band of the first sound source signal, which is different from the first sound source signal. A simulated signal is generated by performing simulated signal processing that includes the specific signal processing and signal processing to simulate the characteristics of the speaker. A third audio signal is generated by extracting the first frequency band of the simulated signal. A fourth audio signal is generated by extracting the second frequency band of the simulated signal. An output audio signal is generated by adjusting the sound pressure of the first frequency band of the simulated signal and the sound pressure of the second frequency band of the simulated signal so that the first difference between the first audio signal and the third audio signal, and the second difference between the second audio signal and the fourth audio signal, are reduced. The output audio signal is then output to the speaker.

[0025] According to this, sound pressure adjustment processing is performed on the simulated signal so that the sound pressure in the first frequency band and the sound pressure in the second frequency band of the simulated signal obtained based on a second sound source signal that has not been pre-adjusted in sound pressure is close to the sound pressure in the first frequency band and the sound pressure in the second frequency band of the first sound source signal that has been pre-adjusted in sound pressure. Therefore, even with an alarm sound based on a second sound source signal, the sound pressure in the first frequency band and the sound pressure in the second frequency band can be brought close to the sound based on a first sound source signal that has been pre-adjusted to meet the specified requirements. Thus, the sound of a sound source that has not been pre-adjusted in sound pressure can be adjusted so that a sound with a specified sound pressure or higher is output at a specified frequency.

[0026] A mobile device according to a sixth aspect of this disclosure comprises a vehicle proximity notification device according to the first or second aspect, and the specific speaker.

[0027] These general or specific embodiments may be implemented using a system, integrated circuit, computer program, or a non-temporary recording medium such as a computer-readable CD-ROM, or any combination of a system, integrated circuit, computer program, and non-temporary recording medium.

[0028] The following embodiment describes a vehicle proximity warning device that can adjust the sound of a sound source that has not undergone prior sound pressure adjustment so that a specified sound pressure is output at a specified frequency.

[0029] The embodiments of the present invention will be described below with reference to the drawings. Note that the embodiments described below are all specific examples of the present invention. The numerical values, shapes, materials, components, arrangement and connection configurations of components, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit the present invention. Furthermore, among the components in the following embodiments, those not described in the independent claim representing the highest-level concept will be described as optional components.

[0030] (Embodiment) This embodiment describes a vehicle proximity warning device mounted on a vehicle.

[0031] Figure 1 is a schematic diagram of a vehicle equipped with a vehicle proximity warning device according to an embodiment.

[0032] Vehicle 40 is an example of a mobile device and comprises a vehicle proximity notification device 10 and a speaker 30. Specifically, vehicle 40 is an automobile, but is not particularly limited to automobiles.

[0033] Speaker 30 outputs sound in response to the audio signal output from the vehicle proximity warning device 10. Speaker 30 is located outside the vehicle 40, for example, in the engine compartment. Therefore, speaker 30 outputs an alarm sound to the outside of vehicle 40 to indicate the proximity of vehicle 40. Speaker 30 has the function of converting electrical signals, which are audio signals, into mechanical vibrations and outputs an alarm sound with sound pressure based on the electrical signals.

[0034] Furthermore, the passenger compartment 41 of vehicle 40 is the space where the occupants of vehicle 40 reside. In other words, the passenger compartment 41 is the space where the occupants of vehicle 40 are located.

[0035] [1. Structure] Next, the configuration of the vehicle proximity warning device 10 will be explained with reference to Figure 2 in addition to Figure 1. Figure 2 is a block diagram showing an example of the functional configuration of the vehicle proximity warning device according to the embodiment.

[0036] The vehicle proximity warning device 10 is a device that notifies people around the vehicle 40 of its proximity by outputting a warning sound from the speaker 30.

[0037] As shown in Figure 2, the vehicle proximity warning device 10 includes an acquisition unit 111, a storage unit 112, a simulated signal processing unit 113, a sound pressure adjustment unit 114, a first filter unit 115, a second filter unit 116, a third filter unit 117, a fourth filter unit 118, a volume pitch control unit 119, and an output unit 120. The vehicle proximity warning device 10 is implemented by a processor such as a DSP, but may also be implemented by a microcomputer or a dedicated circuit, or by a combination of two or more of the processor, microcomputer, and dedicated circuit.

[0038] The acquisition unit 111 acquires a first sound source from the storage unit 112 and generates a first sound source signal. The acquisition unit 111 also acquires a second sound source from the storage unit 112 and generates a second sound source signal. The first and second sound source signals are electrical signals that are audio signals corresponding to a single alarm sound that notifies the outside of the proximity of the vehicle 40. The alarm sound is, for example, an engine sound. The first sound source uses a simulated engine sound or an electronic sound, and the first sound source signal is composed of frequency components, for example, a low-frequency part from 300Hz to 800Hz and a high-frequency part from 1kHz to 5kHz. The first sound source generates a first audio signal that represents a first sound having a first frequency characteristic as an alarm sound. The first frequency response is, for example, a frequency response in which the sound pressure at a first frequency F1 included in the low frequency band below a predetermined frequency Fth is equal to or greater than the first sound pressure, and the sound pressure at a second frequency F2 included in the high frequency band above a predetermined frequency Fth is equal to or greater than the second sound pressure.

[0039] The predetermined frequency Fth is, for example, 1 kHz. Furthermore, the first frequency F1, which serves as the reference for the first frequency band, and the second frequency F2, which serves as the reference for the second frequency band, are frequencies that are not adjacent to each other among multiple frequency bands divided into 1 / 3 octave intervals. For example, the first frequency F1 is 630 Hz. For example, the second frequency F2 is 1 kHz.

[0040] The memory unit 112 stores the first sound source signal and the second sound source signal. The memory unit 112 is a non-volatile memory device. The second sound source signal is an audio signal whose sound pressure has not been pre-adjusted so that the speaker 30 outputs sound at a specified frequency and above a specified sound pressure level.

[0041] The first sound source signal is an audio signal that, when output from speaker 30 after specific signal processing, has a sound pressure in the first frequency band greater than a specified first sound pressure, and a sound pressure in a second frequency band different from the first frequency band greater than a specified second sound pressure. In other words, the first sound source signal is an audio signal whose sound pressure has been pre-adjusted so that a sound with a sound pressure of a specified level or higher is output at a specified frequency. To put it another way, the first sound source signal is processed by the sound pressure adjustment unit 114 with parameters determined by pre-adjusting the sound pressure as a specific signal processing, and when output to speaker 30, a sound with a sound pressure of a specified level or higher is output from speaker 30 at a specified frequency.

[0042] The simulated signal processing unit 113 generates a simulated signal by performing simulated signal processing on the second sound source signal, which includes specific signal processing and signal processing to simulate the characteristics of a specific speaker. The simulated signal processing unit 113 does not perform simulated signal processing on the first sound source signal.

[0043] Figure 3 shows the sound pressure frequency characteristics of a speaker according to the embodiment. Figure 4 shows an example of a simulated filter for simulated signal processing that simulates the sound pressure frequency characteristics of the speaker according to the embodiment.

[0044] In the simulated signal processing, the simulated signal processing unit 113 generates a simulated signal that simulates the audio signal after it is output from the speaker 30 by performing simulated signal processing that simulates the sound pressure frequency characteristics of the speaker 30 as shown in Figure 4. A second-order high-pass / low-pass filter may be used as the simulated filter, or a first-order or third-order speaker filter may be used. The simulated filter may be a combination such as having a low-frequency filter and not having a high-frequency filter, depending on the playback capability of the speaker 30. An FIR filter may be used as the simulated filter, and the characteristics of the speaker 30 may be simulated more precisely.

[0045] The first filter unit 115 generates a first audio signal by extracting the first frequency band of the first sound source signal acquired by the acquisition unit 111. In this way, the first filter unit 115 acquires the first audio signal. In other words, the first filter unit 115 also functions as an acquisition unit that acquires the first audio signal.

[0046] The second filter unit 116 generates a second audio signal by extracting the second frequency band of the first sound source signal acquired by the acquisition unit 111. Thus, the second filter unit 116 acquires the second audio signal. In other words, the second filter unit 116 also functions as an acquisition unit that acquires the second audio signal.

[0047] The sound pressure adjustment unit 114 performs a predetermined sound pressure adjustment on the simulated signal and generates an output audio signal after sound pressure adjustment. The sound pressure adjustment unit 114 does not need to perform sound pressure adjustment on the first input simulated signal. In other words, the sound pressure adjustment unit 114 may output the first input simulated signal as the output audio signal.

[0048] The third filter unit 117 generates a third audio signal by extracting the first frequency band of the output audio signal (or initial simulated signal).

[0049] The fourth filter section 118 generates a fourth audio signal by extracting the second frequency band of the output audio signal (or initial simulated signal).

[0050] The sound pressure adjustment unit 114 calculates a first difference between the first audio signal and the third audio signal, and a second difference between the second audio signal and the fourth audio signal. The sound pressure adjustment unit 114 then generates an output audio signal by adjusting the sound pressure of the first frequency band and the sound pressure of the second frequency band of the simulated signal so that the first and second differences become smaller. Specifically, the sound pressure adjustment unit 114 performs LSM (Least Squares Method) calculations to adjust the sound pressure of the first frequency band and the sound pressure of the second frequency band of the simulated signal so that the first difference between the first audio signal and the third audio signal, and the second difference between the second and fourth audio signals become smaller.

[0051] Here, the first frequency band is included in the low frequency band below a predetermined frequency. The second frequency band is included in the high frequency band above a predetermined frequency.

[0052] The volume and pitch control unit 119 adjusts the volume of the output audio signal to a predetermined volume and the pitch of the output audio signal to a predetermined pitch.

[0053] The output unit 120 outputs an output audio signal adjusted by the volume pitch control unit 119 from the speaker 30. The output unit 120 may also amplify the adjusted output audio signal and then output the amplified output audio signal to the speaker 30.

[0054] [2. Operation] Figure 5 is a flowchart showing an example of the operation of a vehicle proximity warning device according to an embodiment.

[0055] The vehicle proximity warning device 10 acquires the first sound source signal and the second sound source signal (S11).

[0056] Next, the vehicle proximity notification device 10 performs a first filter process on the first sound source signal to generate a first audio signal (S12).

[0057] Next, the vehicle proximity notification device 10 performs a second filter process on the first sound source signal to generate a second audio signal (S13).

[0058] Next, the vehicle proximity warning device 10 generates a simulated signal by performing simulated signal processing on the second sound source signal, which includes specific signal processing and signal processing to simulate the characteristics of a specific speaker (S14).

[0059] Next, the vehicle proximity warning device 10 generates a third audio signal by extracting the first frequency band of the output audio signal (or initial simulated signal) (S15).

[0060] Next, the vehicle proximity warning device 10 generates a fourth audio signal by extracting the second frequency band of the output audio signal (or initial simulated signal) (S16).

[0061] Next, the vehicle proximity notification device 10 generates an output audio signal by performing sound pressure adjustment processing on the second sound source signal based on the first audio signal, the second audio signal, the third audio signal, and the fourth audio signal (S17). Steps S15 and S16 may be performed on the output audio signal after the processing in step S17.

[0062] Next, the vehicle proximity warning device 10 adjusts the volume of the output audio signal to a predetermined volume and the pitch of the output audio signal to a predetermined pitch (S18).

[0063] Next, the vehicle proximity warning device 10 outputs an output audio signal, adjusted by the volume pitch control unit 119, from the speaker 30 (S19).

[0064] Steps S12 and S13 may be performed after step S14. Steps S12, S13, S15, and S16 may be performed in parallel.

[0065] Figure 6 is a flowchart showing a specific example of sound pressure adjustment processing according to the embodiment.

[0066] The vehicle proximity warning device 10 calculates the first difference between the first audio signal and the third audio signal (S21).

[0067] Next, the vehicle proximity notification device 10 determines whether the first difference is greater than or equal to a predetermined value (S22).

[0068] If the vehicle proximity warning device 10 determines that the first difference is greater than or equal to a predetermined value (Yes in S22), it adjusts the sound pressure of the first frequency of the output audio signal to approach the sound pressure of the first frequency of the first sound source signal (S23).

[0069] If the vehicle proximity warning device 10 determines that the first difference is less than a predetermined value (No in S22), or after step S23, it calculates the second difference between the second audio signal and the fourth audio signal (S24).

[0070] Next, the vehicle proximity notification device 10 determines whether the second difference is greater than or equal to a predetermined value (S25).

[0071] If the vehicle proximity warning device 10 determines that the second difference is greater than or equal to a predetermined value (Yes in S25), it adjusts the sound pressure of the second frequency of the output audio signal to be close to the sound pressure of the second frequency of the first sound source signal (S26).

[0072] The vehicle proximity warning device 10 terminates the sound pressure adjustment process if it determines that the second difference is less than a predetermined value (No in S25), or after step S26.

[0073] Furthermore, the processes in steps S21 to S23 and steps S24 to S26 may be performed in parallel, or the processes in steps S24 to S26 may be performed before the processes in steps S21 to S23.

[0074] [3. Effects, etc.] The vehicle proximity warning device 10 according to this embodiment notifies of the proximity of a vehicle 40 by having a speaker 30 located on the vehicle 40 output a warning sound toward the outside of the vehicle 40. The vehicle proximity warning device 10 comprises an acquisition unit, a simulated signal processing unit 113, a third filter unit 117, a fourth filter unit 118, a sound pressure adjustment unit 114, and an output unit 120. The acquisition unit acquires a first audio signal and a second audio signal. The first audio signal is a first sound source signal, and after specific signal processing, when output by the speaker 30, the sound pressure in the first frequency band is greater than a specified first sound pressure, and the sound pressure in a second frequency band different from the first frequency band is greater than a specified second sound pressure. The first audio signal is an audio signal in which the second frequency band of the first sound source signal is extracted. The simulated signal processing unit 113 generates a simulated signal by performing simulated signal processing on a second sound source signal, which is different from the first sound source signal, including specific signal processing and signal processing to simulate the characteristics of a speaker. The third filter unit 117 generates a third audio signal by extracting the first frequency band of the simulated signal. The fourth filter unit 118 generates a fourth audio signal by extracting the second frequency band of the simulated signal. The sound pressure adjustment unit 114 generates an output audio signal by adjusting the sound pressure of the first frequency band of the simulated signal and the sound pressure of the second frequency band of the simulated signal so that the first difference between the first audio signal and the third audio signal, and the second difference between the second audio signal and the fourth audio signal are small. The output unit 120 outputs the output audio signal to the speaker 30.

[0075] According to this, sound pressure adjustment processing is performed on the simulated signal so that the sound pressure in the first frequency band and the sound pressure in the second frequency band of the simulated signal obtained based on a second sound source signal that has not been pre-adjusted in sound pressure is close to the sound pressure in the first frequency band and the sound pressure in the second frequency band of the first sound source signal that has been pre-adjusted in sound pressure. Therefore, even with an alarm sound based on a second sound source signal, the sound pressure in the first frequency band and the sound pressure in the second frequency band can be brought close to the sound based on a first sound source signal that has been pre-adjusted to meet the specified requirements. Thus, the sound of a sound source that has not been pre-adjusted in sound pressure can be adjusted so that a sound with a specified sound pressure or higher is output at a specified frequency.

[0076] For example, even if you want to set a second sound source different from the pre-prepared first sound source as the alarm sound, the sound pressure adjustment process described above is performed, making it easy to adjust the output to ensure that the alarm sound meets legal requirements, such as having a sound pressure above the specified level at the specified frequency. Therefore, the second sound source can be set to various sound sources, which also improves the flexibility of the alarm sound.

[0077] Furthermore, the vehicle proximity warning device 10 according to this embodiment further comprises a first filter unit 115 and a second filter unit 116. The first filter unit 115 generates a first audio signal by extracting a first frequency band of the first sound source signal. The second filter unit 116 generates a second audio signal by extracting a second frequency band of the first sound source signal.

[0078] Therefore, the first and second audio signals can be generated based on the first sound source signal. Consequently, the generated first and second audio signals can be used for sound pressure adjustment processing by the sound pressure adjustment unit without having to store the first and second audio signals, eliminating the need to secure storage capacity for a memory device to store the first and second audio signals.

[0079] Furthermore, in the vehicle proximity warning device 10 according to this embodiment, the first frequency band is included in the low frequency band below a predetermined frequency. The second frequency band is included in the high frequency band above a predetermined frequency.

[0080] Therefore, it is possible to generate sounds that comply with regulations based on the second sound source signal.

[0081] Furthermore, in the vehicle proximity warning device 10 according to this embodiment, the first frequency band and the second frequency band are non-adjacent frequency bands among a plurality of frequency bands divided into 1 / 3 octave intervals.

[0082] Therefore, it is possible to generate sounds that comply with regulations based on the second sound source signal.

[0083] [Differentiation] In the above embodiment, the vehicle proximity notification device 10 is said to include a first filter unit 115 and a second filter unit 116, but it may also be configured without the first filter unit 115 and the second filter unit 116. In this case, the storage unit 112 may store a first audio signal generated by performing a first filter process on the first sound source signal in advance, and a second audio signal generated by performing a second filter process on the first sound source signal in advance. In this case, the acquisition unit 111 acquires the first audio signal and the second audio signal stored in the storage unit 112 and outputs the first audio signal and the second audio signal to the sound pressure adjustment unit 114.

[0084] Furthermore, in the above embodiment, each component may be implemented by being composed of dedicated hardware or by executing a software program suitable for each component. Each component may also be implemented by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0085] Furthermore, each component may be a circuit (or integrated circuit). These circuits may form a single circuit as a whole, or they may be separate circuits. Also, each of these circuits may be a general-purpose circuit or a dedicated circuit.

[0086] Furthermore, general or specific embodiments of the present invention may be implemented as a system, apparatus, method, integrated circuit, computer program, or a computer-readable non-temporary recording medium such as a CD-ROM. Alternatively, they may be implemented as any combination of a system, apparatus, method, integrated circuit, computer program, and computer-readable non-temporary recording medium.

[0087] For example, the present invention may be implemented as a vehicle proximity notification method executed by a vehicle proximity notification device (computer or DSP), or as a program for causing a computer or DSP to execute the above vehicle proximity notification method.

[0088] Furthermore, in the above embodiment, a process performed by a specific processing unit may be performed by another processing unit. Also, the order of the multiple processes in the operation of the vehicle proximity warning device described in the above embodiment may be changed, and the multiple processes may be executed in parallel.

[0089] Furthermore, the present invention also includes forms obtained by applying various modifications to each embodiment that a person skilled in the art could conceive, or forms realized by arbitrarily combining the components and functions of each embodiment without departing from the spirit of the present invention. [Industrial applicability]

[0090] This disclosure is applicable to vehicle proximity warning devices installed in low-noise vehicles such as electric vehicles and hybrid vehicles. [Explanation of Symbols]

[0091] 10. Vehicle proximity warning device 30 speakers 40 vehicles 41 Cabin 111 Acquisition Department 112 Storage section 113 Simulated Signal Processing Unit 114 Sound pressure adjustment section 115 First Filter Section 116 Second Filter Section 117 Third Filter Section 118 Fourth Filter Section 119 Volume Pitch Control Unit 120 Output section

Claims

1. A vehicle proximity warning device that notifies of the vehicle's proximity by having a speaker located on the vehicle output a warning sound toward the outside of the vehicle, An acquisition unit acquires a first audio signal from which the first frequency band of a first sound source signal is extracted, and which, after specific signal processing, is output by the speaker such that the sound pressure in the first frequency band is greater than a specified first sound pressure and the sound pressure in a second frequency band different from the first frequency band is greater than a specified second sound pressure, and a second audio signal from which the second frequency band of the first sound source signal is extracted. A simulated signal processing unit generates a simulated signal by performing simulated signal processing on a second sound source signal different from the first sound source signal, which includes the specific signal processing and signal processing for simulating the characteristics of the speaker. A third filter unit generates a third audio signal by extracting the first frequency band of the simulated signal, A fourth filter unit generates a fourth audio signal by extracting the second frequency band of the simulated signal, A sound pressure adjustment unit generates an output audio signal by adjusting the sound pressure of the first frequency band of the simulated signal and the sound pressure of the second frequency band of the simulated signal so that the first difference between the first audio signal and the third audio signal and the second difference between the second audio signal and the fourth audio signal are reduced. The system includes an output unit that outputs the aforementioned audio signal to the speaker. Vehicle proximity warning device.

2. moreover, A first filter unit that generates the first audio signal by extracting the first frequency band of the first sound source signal, The system includes a second filter unit that generates the second audio signal by extracting the second frequency band of the first sound source signal. The vehicle proximity warning device according to claim 1.

3. The first frequency band is included in the low frequency band below a predetermined frequency, The second frequency band is included in the high-frequency band above the predetermined frequency. The vehicle proximity warning device according to claim 1 or 2.

4. The first frequency band and the second frequency band are non-adjacent frequency bands among a plurality of frequency bands divided into 1 / 3 octave intervals. The vehicle proximity warning device according to claim 3.

5. A vehicle proximity notification method that notifies of the proximity of a vehicle by having a speaker installed in the vehicle output an alarm sound toward the outside of the vehicle, A first audio signal is obtained in which the first frequency band of a first sound source signal is extracted, and the second audio signal is obtained in which the second frequency band of the first sound source signal is extracted, and the first audio signal is obtained in which the second frequency band of the first sound source signal is extracted, such that when output by the speaker after specific signal processing, the sound pressure in the first frequency band is greater than a specified first sound pressure, and the sound pressure in the second frequency band different from the first frequency band is greater than a specified second sound pressure. A simulated signal is generated by performing simulated signal processing on a second sound source signal, which is different from the first sound source signal, including the specific signal processing and signal processing to simulate the characteristics of the speaker. A third audio signal is generated by extracting the first frequency band of the simulated signal. A fourth audio signal is generated by extracting the second frequency band of the simulated signal. The output audio signal is generated by adjusting the sound pressure of the first frequency band of the simulated signal and the sound pressure of the second frequency band of the simulated signal so that the first difference between the first audio signal and the third audio signal and the second difference between the second audio signal and the fourth audio signal are reduced. The aforementioned output audio signal is output to the speaker. Vehicle proximity notification method.

6. A vehicle proximity warning device according to claim 1 or 2, The aforementioned specific speaker, Mobile device.

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