JPH07327068A - Active noise elimination device - Google Patents

Abstract

PURPOSE:To provide a device with simple configuration for pleasant conversation without being affected by noise under noisy environment. CONSTITUTION:An active headphone 20 is provided with a phone 22R for right ear of a passenger and a phone 22L for a left eye of passenger each having sensor microphones 34R, 34L around each auditory canal. The output signal from the sensor microphones 34R, 34L is given to a telephone set 90 via a microphone amplifier 24 and also to an ECU 28 receiving a siren signal S1. A mixer 30 synthesizes a communication signal T1 from the telephone set 90 and a noise elimination signal S3 for eliminating noise generated based on the input signal by the ECU 28 and provides an output to each of the phones 22R, 22L via the phone amplifier 32. Since the sensor microphones 34R, 34L are used in common for the transmitter or the like and the input device or the like to generate the eliminating signal, then simple configuration is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active noise eliminating device, and in particular, it eliminates unnecessary noise such as ambient noise by using a device for sound emission such as a headphone device and the like. The present invention relates to an active noise reduction device that comfortably communicates.

[0002]

2. Description of the Related Art In order to listen to a sound by a communication signal from a telephone or the like, or to listen to a talk from a remote party, a sound is attached to a person's head and corresponds to an input acoustic signal. There is a headphone device that emits sound in a sound emission space formed near the ear canal of a person covered with headphones or the like.
With this headphone device, ambient noise and the like may intrude into the sound emission space at the same time, so that the sound that should be heard may be missed. In order to do so, there is a communication device as an active noise removing device that removes ambient noise (Japanese Patent Laid-Open No. 5-110650).

In this communication device, a microphone for detecting ambient noise is installed separately from the transmitter, and a phase inversion signal obtained by inverting the phase of the output signal of the microphone is added to the output of the transmitter. Send. Also, the phase-inverted signal is added to the received signal and output from the handset. In this way, the sound component is picked up by the microphone, and the noise component signal of the opposite phase of the noise component signal obtained from the output sound signal is synthesized with the output of the transmitter, and by the interference action by this synthesis,
The noise component is removed. As a result, the person wearing the communication device can comfortably talk in a noise environment without being affected by the noise.

[0004]

However, the conventional active noise eliminator has a problem that the structure is complicated because the microphone, the transmitter and the receiver are separate entities.

Further, like a conventional active noise eliminator, a microphone is provided separately from the transmitter to generate a phase inversion signal which is the opposite phase of the output signal of the microphone.
When this phase inversion signal and the output of the transmitter are added (synthesized), the voice of the transmitter to be transmitted may be removed. That is, there is a possibility that a part of the voice of the speaker is mixed in the microphone, and a phase inversion signal that is the opposite phase is generated from the output signal of the microphone corresponding to the voice of the speaker.

In consideration of the above facts, an object of the present invention is to obtain an active noise eliminator which can be provided with a simple structure in order to comfortably talk in a noise environment without being affected by the noise. .

[0007]

In order to achieve the above object, an active noise eliminating device of the present invention is arranged near a person's auditory meatus entrance, and is capable of generating a sound around the person and a voice uttered by the person. A sound collecting unit that collects a sound and outputs a sound collecting signal corresponding to the collected sound, and a reference signal corresponding to a predetermined sound and a noise removing signal for removing noise based on the sound collecting signal. A signal generating means for generating and outputting, a signal input / output means for outputting the collected sound signal to a communication line and outputting a communication signal inputted from the communication line, a sound corresponding to the noise removal signal and the communication Sound emitting means for emitting a sound so that the sound corresponding to the signal is synthesized near the entrance of the ear canal.

[0008]

In the active noise eliminator of the present invention, the sound near the entrance to the ear canal of the person is picked up by the sound collecting means. The sound near the entrance to the auditory canal includes the sound around the person and the voice uttered by the person. Along with this sound collection, the sound collection means outputs a sound collection signal corresponding to the collected sound. The signal generating means generates and outputs a noise removal signal for removing noise based on the sound collection signal and a reference signal corresponding to a predetermined sound. The reference signal includes a siren signal for emitting the siren. Therefore, since this noise removal signal is generated based on the sound collection signal and the reference signal corresponding to the predetermined sound, it does not include a signal with an opposite phase that removes the voice uttered by the person.
The signal input / output unit outputs the collected sound signal to a communication line such as a telephone line or a wireless line, and also outputs a communication signal input from the communication line. The sound emitting means emits sound such that the sound corresponding to the generated noise removal signal and the sound corresponding to the input communication signal are combined near the ear canal entrance. Therefore, in the vicinity of the entrance to the ear canal of a person, the sound corresponding to the signal from which noise such as siren should be removed, the sound corresponding to the input communication signal, and the voice or the like for conversation made by the person are superimposed. Will be. For this reason, the sound pickup means can remove noise and can clearly pick up a voice or the like for conversation made by a person. As described above, the sound collecting means also serves as a transmitter for communication and an input device for generating a noise removal signal for removing noise. The sound near the entrance to the auditory canal of the person in which the sound collecting means is disposed is removed by the sound emission of the sound corresponding to the noise removal signal. Therefore, the person reduces the noise and the noise is reduced in the noise environment. You can talk comfortably without being influenced by.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. In this embodiment, the present invention is applied to an active noise reduction device mounted on an emergency vehicle such as an ambulance.

As shown in FIG. 1, the active noise reduction system 10 of the first embodiment comprises active headphones 20 which are mounted on the head of an occupant of an emergency vehicle (not shown). The active headphone 20 includes a pair of left and right phones including a phone 22R that is worn for the right ear of the occupant and a phone 22L that is worn for the left ear of the occupant (see FIG. 3 for details). ). Sensor microphones 34R and 34L as sound collecting means are arranged at positions near the left and right ear canals of the occupant of each of the phones 22R and 22L. These sensor microphones 34R and 34L are
The sound emitted by the occupant and the sounds around the occupant are both collected.

Each of the sensor microphones 34R and 34L is connected to the microphone amplifier 24. Microphone amplifier 24
Is an amplified signal S8 obtained by amplifying a weak signal S7 corresponding to the sound picked up by each of the sensor microphones 34R and 34L.
Is output to the telephone 90 as a signal input / output means,
The signal is output to an electric control unit (hereinafter referred to as ECU) 28 as a signal generating means. Further, a siren amplifier 14 is connected to the siren device 12 arranged in an emergency vehicle (not shown), and the siren signal S1 output from the siren drive circuit 16 is input to the siren amplifier 14. This siren signal S1 is transmitted to the ECU 2
8 is input.

As is well known, the telephone 90 comprises a handset 90A, which is a handset, and a main unit 90B.
It is connected to a communication line (not shown). The communication lines (not shown) include a subscriber line, an ISDN line, a wireless telephone line, and a network line. The amplified signal S8 can be input to the telephone 90 of this embodiment. The telephone 90 is also connected to the mixer 30, and an output signal of the telephone 90, that is, a voice signal of conversation from another telephone or the like via a communication line (not shown) is output to the mixer 30 as a communication signal T1. . EC
U28 is a noise removal signal S3 for removing noise that an occupant wearing the active headphone 20 feels bothersome from the collected sound signal corresponding to the sound collected by each of the sensor microphones 34R and 34L and the input siren signal. Is generated and output. The mixer 30 synthesizes the communication signal T1 and the noise removal signal S3 and outputs the synthesized signal S4 to the phone amplifier 32.

The phone amplifier 32 generates a drive signal S5 for driving each of the phones 22R and 22L based on the input composite signal S4 and outputs the drive signal S5 to each of the phones 22R and 22L. .

The phones 22R and 22L, the phone amplifier 32, and the mixer 30 as a synthesizing unit constitute a sound emitting unit.

As shown in FIG. 2, the ECU 28 is composed of an adaptive filter 40, an adaptive algorithm 42, a siren sound transmission circuit 44, and an actuator-sensor transmission circuit 46. In FIG. 2, for simplification of description, the active headphones 20 will be described using only the phone 22R for the right side of the occupant.

The siren signal S1 is input to the adaptive filter 40 via the siren sound transmission circuit 44 of the ECU 28. The siren sound transmission circuit 44 is a circuit having a transfer characteristic equivalent to the time required for the siren emitted by the siren signal S1 output from the siren drive circuit 16 to reach the sensor microphone 34R and the increase / decrease of the signal. .
That is, the siren signal S1 is input to the siren device 12 via the siren amplifier 14 and is emitted. This siren propagates in the cabin of an emergency vehicle (not shown), and the sensor microphone 34R near the ear canal of the occupant in the vehicle.
To reach. The propagation in the cabin of the emergency vehicle (not shown) can be approximated by the cabin transmission circuit 48, and the transmission characteristics of the siren sound due to the configurations of the siren amplifier 14, the siren device 12, and the cabin transmission circuit 48 can be obtained. As a result, the siren emitted from the siren device 12 as the siren sound transmission circuit 44 propagates in the cabin of the emergency vehicle (not shown) and the sensor microphone 34.
The transfer characteristic until reaching R can be obtained. The signal S2 output from the siren sound transmission circuit 44 is
The characteristics of the siren sound near the auditory canal of the passenger in the vehicle are approximated.

This signal S2 is input to the adaptive algorithm 42 via the actuator-sensor transmission circuit 46. Since the phone 22R and the sensor microphone 34R have a space, the sound emitted by the phone 22R has transfer characteristics such as time and increase / decrease in signal before reaching the sensor microphone 34R. Therefore, the actuator-sensor transmission circuit 46 is a circuit equivalent to this transmission characteristic. Therefore, the signal S2a output from the actuator-sensor transmission circuit 46 is approximated to the characteristic of the siren sound picked up by the sensor microphone 34R.

In this adaptive algorithm 42, based on the input signal S2a and the amplified signal S8 of the sensor microphone 34R output via the microphone amplifier 24, the position of the sensor microphone 34R is set in the cabin of an emergency vehicle (not shown). The noise removal signal S3 having the opposite phase to the phase of the siren propagating and reaching the sensor microphone 34R is applied to the adaptive filter 4
The correction signal H1 for outputting from 0 is output.

The adaptive filter 40 includes a sensor microphone 34R.
Noise removal signal S that has a phase opposite to that of the siren at the position
3 is output to the mixer 30. In this mixer 30, the communication signal T1 and the noise removal signal S3 input from the telephone 90 are input.
A combined signal S4 obtained by combining and is output. This composite signal S
4 is input to the phone 22R via the phone amplifier 32.

Therefore, the synthesized signal S4 is formed by superimposing the communication signal T1 which is a voice signal from a communication line (not shown) and the noise removal signal S3 of the opposite phase generated to remove the siren. Therefore, in the space near the ear canal of the occupant located near the phone 22R, the sound emitted from the phone 22R by the combined signal S4 and the siren emitted by the siren device 12 overlap with each other, and the siren is reversed. It is removed by interfering with the phase signal. In the space near the ear canal of the occupant located near the phone 22R, the sound corresponding to the audio signal from the communication line (not shown) is also propagated.

The sound emitted from the phone 22R,
The voice emitted by the occupant and the ambient sound are collected by the sensor microphone 34R. At this time, since there is a space between the phone 22R and the sensor microphone 34R, the sound emitted from the phone 22R is equivalent to being transmitted through the actuator-sensor transmission circuit 46 having the above-mentioned transmission characteristics. is there.

In the space around the sensor microphone 34R, the siren is removed as described above. Therefore, the signal S7 output from the sensor microphone 34R becomes a signal corresponding to the voice emitted by the occupant and the ambient sound with the siren removed. Since this sensor microphone 34R is connected to the telephone 90 via the microphone amplifier 24, the voice or the like produced by the occupant can be output from the telephone 90 to a communication line (not shown) without using the handset 90A. The resulting signal becomes the signal corresponding to the sound from which the siren has been removed. As a result, in a device (telephone or the like) that gives a signal to the other via the communication line, it is possible to listen to a clear voice produced by the occupant with the siren suppressed.

As shown in FIGS. 3 and 4, the active headphone 20 of the present embodiment is not a closed type, but a ventilator to the outside so that the voice emitted by the occupant can be easily picked up by the sensor microphone. It is configured with a possible space portion 54. That is, the phone 22L that is worn for the left ear of the occupant of the active headphones 20 is connected to the phone 22R that is worn for the right ear by the arm portion 60. The speaker portion 56 of the phone 22L is located at the end of the arm portion 60. The sensor microphone 3 is provided near the ear canal of the occupant of the speaker unit 56.
4L is provided. Further, the four regions along the outer periphery of the speaker portion 56 on the sound output side are formed as pillar portions 58 having a predetermined length. At the tip of this column 58,
A ring-shaped ear pad 52 that contacts the head of the occupant is attached. Therefore, when the phone 22L is mounted near the auditory canal of the occupant, the ear pad 52 and the speaker unit 56 are separated from each other at an interval depending on the length of the column portion 58.
Therefore, when the phone 22L is attached, it has a space 54 that allows ventilation to the outside. A porous material having a high air permeability such as a sponge may be provided in the space 54.

Although not shown, the right phone 2
2R has the same configuration. In addition, as the configuration of the active headphones 20, as the optimal shape obtained experimentally,
It is preferable that the space 54 be as large as possible.
In this embodiment, the active headphones 20 having the struts 58 at the four places shown in FIGS. 5 and 6 are used.

As described above, in this embodiment, the sound corresponding to the noise removal signal for removing the noise such as siren is emitted from the phone, and the output from the sensor microphone is input to the telephone. The occupant's conversation picked up by the sensor microphone is detected as a sound in which ambient noise is removed by a noise removal signal from a phone near the sensor microphone. Therefore, the conversation of the occupant can be directly transmitted to the destination by using the sensor microphone, so that the device can be configured easily without newly disposing a conversation microphone.

Further, the voice at the time of reception, which is the communication signal supplied through the communication line connected to the telephone, is not mixed with the ambient noise due to the noise elimination signal output from the phone at the same time, which is clear. Can be heard.

Further, since the siren or the like which is a noise is attenuated by the sound emitted from the phone, the occupant can continue to wear the active headphones without feeling the annoyance due to the siren or the like.

In the active noise eliminator of the above embodiment, the distance between the sensor microphone and the phone is short, so howling may occur due to the sound emitted by the phone. In this case, as shown in FIG. 5, it is preferable to correct the signal input to and output from the telephone 90 via the equalizer 92 so that howling does not occur.
Further, the equalizer 92 may be arranged on either one of the input signal and the output signal.

As another method for preventing howling, the left microphone (or right microphone) may be a transmission-only microphone and the right speaker (or left speaker) may be a reception-only speaker.

It should be noted that the output of the sensor microphone picked up as the ambient environmental sound is input to the mixer 30 through a filter that passes a signal of a predetermined frequency or frequency range and is synthesized, so that the sound is attenuated by mounting the phone. You may make it supplement the environmental sound expected to be played.

Next, a case where the present invention is applied to an active headphone having a closed type phone will be described as a second embodiment. Since this embodiment has substantially the same configuration as the above embodiment, the same parts are designated by the same reference numerals and detailed description thereof will be omitted. Although the second embodiment has a separate configuration without combining the respective signals by using a mixer, in order to easily realize the configuration, noise removal is performed by using an external speaker provided in advance in the vehicle. It is preferable to perform sound emission for.

As shown in FIG. 6, the active headphone 21 of the second embodiment is a closed type phone 23R, 23R.
Has L. Since each of the phones 23R and 23L is a hermetically sealed type, each of the sensor microphones 34L and 34R corresponds to the speaker unit 56 (see FIG. 3).
It is arranged outside 23L. Each sensor microphone 34
L and 34R are connected to the adaptive algorithm 42 of the ECU 28, and are also connected to the telephone 90 as described above. The telephone 90 is connected to each of the phones 23R and 23L.

Further, in the second embodiment, the external speakers 36R and 3R for removing the noise that the passenger feels troublesome.
6L is arranged in an emergency vehicle (not shown). As the external speakers 36R and 36L, speakers provided in advance in an emergency vehicle (not shown) may be used. Therefore,
In this embodiment, the sound emitting means is constituted by the phones 23R and 23L and the external speakers 36R and 36L.

In the ECU 28, as explained above,
The siren signal S1 is input to the adaptive filter 40 in the siren sound transmission circuit 44 as a signal S2 approximated to the characteristic of the siren sound in the vicinity of the ear canal of the occupant in the vehicle.
Further, the signal S2 is input to the adaptive algorithm 42 as a signal S2a that is approximated to the characteristic of the siren sound picked up by the sensor microphone 34R in the actuator-sensor transmission circuit 46.

The adaptive algorithm 42 outputs the correction signal H1 for outputting the noise removal signal S3 having the opposite phase to the phase of the siren from the adaptive filter 40 based on the input signal S2a and the output signal of the sensor microphone. .
The adaptive filter 40 outputs to the external speakers 36R and 36L a noise removal signal S3 having a phase opposite to that of the siren at the positions of the sensor microphones 34R and 34L.

Therefore, the sensor microphone 34 of the second embodiment.
At R and 34L, the sound corresponding to the noise removal signal S3 that is in the opposite phase to the phase of the siren propagating in the cabin of an emergency vehicle (not shown) and reaching the sensor microphone and the siren emitted from the external speakers 36R and 36L. It will be picked up. Therefore, the sound pickup signals output from the sensor microphones 34R and 34L are signals in which only the siren is attenuated by the interference among the sound pickup signals including the voices emitted by the occupant.

In the above embodiment, the case where a single active headphone is connected to the telephone has been described.
The present invention is not limited to this, and the telephone may be connected to a network such as an extension line to which a plurality of active headphones are connected.

[0038]

As described above, according to the present invention, the sound collecting means also serves as a transmitter for communication and an input device for generating a noise removal signal for removing noise. Therefore, the sound of a person's conversation or the like picked up by the sound pick-up means is picked up as a sound in which ambient noise is removed according to the noise removal signal, and a clear sound such as a passenger's conversation is picked up only by the sound pick-up means. Therefore, there is an effect that the active noise reduction device can be provided with a simple configuration.

Since the noise corresponding to the noise elimination signal emitted from the sound emitting means is eliminated near the entrance of the auditory canal of the person, the sound corresponding to the communication signal by the signal input / output means is The effect is that it can be heard clearly without being mixed with the noise of. Also,
Although noise is removed near the entrance of a person's ear canal, the noise removal signal does not include signals such as anti-phase signals that remove the voice emitted by the person, so the voice emitted by the person is not attenuated and is clear. There is an effect that a sound such as a conversation of a different person can be collected by the sound collecting means.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an active noise reduction device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a signal flow including a schematic configuration of an ECU of the active noise reduction device.

FIG. 3 is an external perspective view showing a schematic configuration of a phone included in the active headphones of the active noise reduction device according to the first embodiment.

4 is a view in the direction of arrows I-I in FIG.

FIG. 5 is a block diagram showing a schematic configuration of an active noise reduction device capable of preventing howling by a telephone.

FIG. 6 is a block diagram showing a schematic configuration of an active noise reduction device according to a second embodiment.

[Explanation of symbols]

 10 Active Noise Elimination Device 28 ECU (Signal Generation Means) 34R, 34L Sensor Microphone (Sound Collection Means) 90 Telephone (Signal Input / Output Means) S1 Siren Signal (Reference Signal)

Claims (1)

[Claims] 1. A sound collecting unit which is arranged near an entrance of a person's ear canal and which collects a sound around the person and a sound produced by the person and outputs a sound collecting signal corresponding to the collected sound. A signal generating means for generating and outputting a noise removal signal for removing noise based on a reference signal corresponding to a predetermined sound and the sound collection signal, and outputting the sound collection signal to a communication line, A signal input / output unit that outputs a communication signal input from the communication line, and emits a sound so that the sound corresponding to the noise removal signal and the sound corresponding to the communication signal are combined near the ear canal entrance. An active noise eliminator comprising a sound emitting means.