The present disclosure relates to a sound collecting apparatus, a arrival direction estimating apparatus, and a vibration information collecting apparatus for an acoustic signal arriving from the outside of a mobile body.
As disclosed in Non Patent Literature 1, techniques for installing a microphone on the inner side of a vehicle and collecting sounds inside the vehicle are known as related technologies.
Non Patent Literature 1: Nippon Telegraph and Telephone Corporation, “Speech Enhancement Technology for In-car Communication”, [Retrieved on May 22, 2019], Internet <http://www.ntt.co.jp/RD/active/201802/en/pdf_eng/F10_e.pdf>.
However, a technology for collecting sounds arriving from outside of a vehicle using a microphone disposed inside the vehicle is not known. An objective of the present disclosure is to collect sounds arriving from the outside of a mobile body using a microphone disposed inside the mobile body.
A sound collecting apparatus according to the present disclosure is attached to a mobile body. The sound collecting apparatus according to the present disclosure includes a microphone that is directly or indirectly in contact with an outer face member, which is a member forming an outer face of the mobile body, from an inner side of the mobile body and is configured to collect a sound propagating through the outer face member.
According to the sound collecting apparatus of the present disclosure, a microphone that is in contact with an outer face member from the inner side is provided, and thus sounds arriving at the outer face of a mobile body can be collected by a microphone disposed inside the mobile body.
Hereinafter, embodiments of the present disclosure will be described in detail. Components having the same function are denoted by the same reference signs, and redundant description thereof will be omitted.
In addition, as illustrated in
In a case where the microphone has directivity, the microphone is disposed in a direction in which sounds propagating from the outer face of the outer face member 80 to the inner side are collected. In addition, in the present disclosure, a “window glass” is appropriate as the outer face member 80, and thus the effect can be more easily acquired in a case where the “mobile body 90” is a riding object such as a vehicle. However, the present disclosure can also be used in objects in which a person does not ride such as a radio-controlled car, an unmanned airplane, and the like, in other words, objects having no window glass.
The sound collecting apparatus 100 according to the present disclosure includes the microphone 110 that is in contact with the outer face member 80 from the inner side, and thus sounds arriving at the outer face of the mobile body 90 can be collected by the microphone 110 disposed inside the mobile body 90. In addition, the sound collecting apparatus 100 can be disposed on the inside of a mobile body having a good environment, and thus can be less influenced by environmental factors such as weather and the like at the time of collecting sounds.
The First Modification
The sound collecting apparatus 100 may further include an equalizer 120. The equalizer 120 receives an acoustic signal that is output from the microphone 110 as an input. The equalizer 120 corrects the input acoustic signal in accordance with frequency characteristics that are opposite to the frequency characteristics of the outer face member 80 when sounds propagate from the outer face to the inner side (S120). Glass has a frequency (resonant frequency) that easily vibrates, a sound can easily propagate to the microphone at that frequency, and the sensitivity of the resonant frequency becomes high with characteristics of a combination of the glass and the microphone. In addition, there is a feature that a glass face is less likely to vibrate as the frequency becomes higher, and there is a trend that the sensitivity becomes lower as the frequency is higher. In order to correct this, by including an equalizer set such that a gain of a signal having a high frequency is raised, and a gain for the resonant frequency of the glass is lowered, a flat frequency characteristic can be achieved. In this way, by including the equalizer 120, even when sounds of the outside are collected through the outer face member 80, a flat frequency characteristic can be achieved. The frequency characteristics of the outer face member 80 when sounds propagate from the outer surface to the inner side are measured using the actual outer face member 80.
The Second Modification
In the First Embodiment and the First Modification described above, the measuring target has been described as “sounds”. However, a sound is one type of vibration, and thus, the measuring target may be “vibration”. In such a case, the sound collecting apparatus 100 is called a “vibration information collecting apparatus”, and the microphone 110 is called a “sensor”. Details on this are as follows. The vibration information collecting apparatus is attached to a mobile body 90. The vibration information collecting apparatus includes a sensor that is directly or indirectly in contact with an outer face member 80, which is a member forming an outer face of the mobile body 90, from the inner side of the mobile body 90 and configured to collect information of vibration propagating through the outer face member 80.
Glass is appropriate as the outer face member 80, and, the sensor is disposed in a direction in which the information of vibration propagating from the outer face of the outer face member 80 to the inner side is collected in a case where the sensor has directivity, which are the same as in the First Embodiment.
The vibration information collecting apparatus according to the present disclosure includes the sensor that is in contact with the outer face member 80 from the inner side and thus can collect the information of vibration arriving at the outer face of the mobile body 90 using the sensor disposed inside the mobile body 90.
There are the N sound collecting apparatus 100-1, . . . , N, and thus there are N microphones 110-1, . . . , N. The processing differs depending on how the microphones are disposed, and thus two cases will be described separately. A first case, as illustrated in
A second case, as illustrated in
When N is equal to or greater than 3, the first case and the second case may be combined. For example, N may be set to 6, three sound collecting apparatus 100-1, . . . , 3 may be disposed in one outer face member 80-1, and three sound collecting apparatus 100-4, . . . , 6 may be disposed in the other outer face member 80-2. A direction of arrival may be estimated by performing case classification of a case where only the sound collecting apparatus 100-1, . . . , 3 disposed in the outer face member 80-1 are used, a case where only the sound collecting apparatus 100-4, . . . , 6 disposed in the outer face member 80-2 are used, a case where the six sound collecting apparatus 100-1, . . . , 6 are used, and the like in accordance with a direction of arrival of sounds.
The arrival direction estimating apparatus according to the Second Embodiment includes the microphones that are in contact with the outer face members from the inner side, and thus sounds arriving at the outer face of the mobile body can be collected by the microphones disposed inside the mobile body. In addition, the arrival direction estimating apparatus according to the Second Embodiment can be disposed on the inside of a mobile body having a good environment, and thus can be less influenced by environmental factors such as weather and the like in a case where the direction of arrival of sounds is estimated.
The First Modification
The sound collecting apparatus 100-n may further include an equalizer 120-n. The equalizer 120-n receives an acoustic signal that is output from the microphone 110-n as an input. The equalizer 120-n corrects the input acoustic signal in accordance with frequency characteristics that are opposite to the frequency characteristics of the outer face member 80-n when sounds propagate from the outer face to the inner side. In this way, by including the equalizer 120-n, even when sounds of the outside are collected through the outer face member 80-n, a flat frequency characteristic can be achieved. The frequency characteristics of the outer face member 80-n when sounds propagate from the outer surface to the inner side is measured using the actual outer face member 80-n.
Program and Recording Medium
The processing operations of the equalizer 120 and the estimation unit 200 may be performed by causing the recording unit 2020 of the computer illustrated in
The program in which the processing details are described can be recorded on a computer-readable recording medium. The computer-readable recording medium, for example, may be any type of medium such as a magnetic recording device, an optical disc, a magneto-optical recording medium, or a semiconductor memory.
The program is distributed, for example, by selling, giving, or lending a portable recording medium such as a DVD or a CD-ROM with the program recorded on it. Further, the program may be stored in a storage device of a server computer and transmitted from the server computer to another computer via a network, so that the program is distributed.
For example, a computer executing the program first temporarily stores the program recorded on the portable recording medium or the program transmitted from the server computer in the own storage device. When the computer executes the processing, the computer reads the program stored in the recording medium of the computer and executes processing according to the read program. As another execution mode of this program, a computer may directly read a program from a portable recording medium and execute processing according to the program. The computer may also sequentially execute processing in accordance with the program transmitted from the server computer each time the program is received from the server computer. In another configuration, the processing may be executed through a so-called application service provider (ASP) service in which functions of the processing are implemented just by issuing an instruction to execute the program and obtaining results without transmission of the program from the server computer to the computer. The program in this form is assumed to include information which is information provided for processing of a computer and is equivalent to a program (data or the like that has characteristics regulating processing of the computer rather than a direct instruction for a computer).
Also, in the present embodiment, the apparatus is configured by executing a predetermined program on a computer. However, at least a part of the processing contents may be implemented by hardware.
Filing Document | Filing Date | Country | Kind |
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PCT/JP2019/022567 | 6/6/2019 | WO |