JP2965301B2 - Sound collector - Google Patents

Abstract

PURPOSE:To collect sound with a small noise component by arranging a main acoustic input means and plural subordinate acoustic input means at respective necessary positions and erasing acoustic signals of the subordinate acoustic input means from an acoustic signal of the main acoustic input means. CONSTITUTION:A microphone 21 as the main acoustic input means is arranged nearby on a microphone array plate 11 nearby a object sound source of sound collection and microphones 22 - 28 as the subordinate acoustic means are arranged at distributed positions around the microphone 21. An electric signal corresponding to the main sound outputted by the microphone 21 is processed by an A/D converter and an adaptive filter and electric signals corresponding to subordinate sounds from the microphones 22 - 28 are processed similarly; and the total of the subordinate sound processed data is subtracted from the main sound processed data to realize small-noise, high-quality sound collection.

Description

Description: Object of the Invention (Industrial application field) The present invention relates to a device for collecting sound emitted from a sound source at a specific position, and in particular, to sound (noise) generated by many other sound sources. The present invention relates to a sound collection device for selectively collecting, at a high gain, sound (main sound) generated by a sound source at the specific position.

(Prior Art) For example, when a driver (driver) operates various in-vehicle devices on a vehicle, if the number of operable switches is large, the position of the switch to be operated is searched and a finger is positioned on the switch. Since it is necessary to visually confirm the above, there is a problem in terms of safety in driving the vehicle if various in-vehicle devices are controlled by operating a driver switch while the vehicle is running.

In order to eliminate the need for visual recognition and finger manipulation, the voice recognition device detects the driver's utterance (main sound), identifies a command by the utterance, and controls the in-vehicle device in accordance with the command. It has been proposed.

However, especially on a vehicle, the level of external noise (noise) input to the voice recognition device together with the voice of the driver (main sound) may be large, which may cause a significant inconvenience in voice recognition. Examples of the external noise include a sound from outside the vehicle, an engine sound of the vehicle, a sound from an acoustic device in the vehicle, and a voice of a passenger.

Therefore, when a specific switch is operated, the output of the on-board acoustic device is reduced and the window glass is closed in order to reduce the noise level in preparation for voice input. This is proposed in Japanese Patent Publication No. 29755. In addition, the present inventors have provided a sound collecting device for clearly extracting a driver's utterance from the sound of an audio speaker or engine sound (Japanese Patent Application Nos. 1-77776 and 1-79512). .

(Problems to be Solved by the Invention) In the case of performing a specific switch operation before voice input in order to reduce the noise bell, this operation involves a troublesome operation, and it is necessary to wait until the window glass is completely closed. There is a problem that it takes time to start voice input.

In addition, the sound collectors proposed in Japanese Patent Application Nos. 1-77776 and 1-79512 that perform acoustic signal processing on noise from speakers, engines, and the like are provided with a sound source such as audio equipment at a specific position. (Noise) generated by the vehicle, so-called fixed noise, noise can be suppressed and the voice signal (main sound) can be separated with high gain, but noise from a sound source outside the vehicle such as an oncoming vehicle, that is, moving noise, Low noise suppression effect, voice signal (main sound)
Is not enough for high gain separation. That is, for noise generated by a noise source at a specific position, the main sound emitted by the sound source to be collected can be collected with high gain, but for noise generated by other noise sources, Low noise suppression effect.

SUMMARY OF THE INVENTION It is an object of the present invention to collect, with high gain, a main sound emitted from a sound source to be collected, not only for a noise source at a specific position but also for noise generated by other noises.

[Means for solving the problem]

The sound collection device of the present invention is located near a sound source to be collected, and converts a sound into an electric signal.
And a plurality of sub-sound input means (22-28) for converting sound into an electric signal are distributed around the main sound input means (21) in such a manner that the plurality of sub-sound input means (22-28) surround the main sound input means (21). An array plate (22) arranged; and a sub sound input means (22 to 2) based on an electric signal generated by the main sound input means (21).
And 8) an acoustic signal processing means (100) for outputting an acoustic signal substantially eliminating the electric signal generated by 8). In addition,
Symbols in parentheses indicate corresponding elements of the embodiment shown in the drawings and described later.

[Action]

Since the auxiliary sound input means (22 to 28) are dispersedly arranged on the array plate (11) so as to surround the main sound input means (21) with the main sound input means (21) as the center, the sound source to be collected The sound (noise) emitted by other sound sources first reaches the auxiliary sound input means (22 to 28) and then reaches the main sound input means (21), so that the main sound input means (21) generates an electric signal corresponding to the noise. At this time, the electrical signal corresponding to the noise generated by the sub sound input means (22 to 28) has reached the signal processing means (100). Therefore, the acoustic signal processing means (100)
However, a sound signal is output in which the electric signal generated by the sub sound input means (22 to 28) is substantially eliminated from the electric signal generated by the main sound input means (21). The components are reduced.

On the other hand, the main sound emitted by the sound source to be collected first reaches the main sound input means (21), and after a certain time delay, reaches the sub sound input means (22 to 28). The electric signal generated by the main sound input means (21) has a certain delay with respect to the electric signal generated by the main sound input means (21). Has a somewhat distorted waveform,
It is output as an acoustic signal.

As described above, whether the noise is emitted from a fixed sound source or a moving sound source, the noise is largely suppressed in the emitted sound signal, and the sound collection gain of the main sound generated by the sound source to be collected is high. .

In order to further increase the sound collection gain, in a preferred embodiment of the present invention, the sound collection input means (21) has directivity toward the sound source to be input; the secondary sound input means (22-28) The sound signal processing means (100) has directivity in a direction opposite to the direction toward the main sound input means (21); the electric signal generated by the main sound input means (21) and the auxiliary sound input means (22). ~ 28)
An adaptive filter (62-68) for generating an electric signal whose difference from the electric signal generated by the main sound input means (21) is substantially minimum, and an adaptive filter (62-68) based on the electric signal generated by the main sound input means (21).
And a subtracting means (70) for outputting an acoustic signal obtained by subtracting the electric signal generated by the subtraction means.

According to this, the main sound input means (21) converts the main sound generated by the sound source to be collected into a high-level electric signal, and the auxiliary sound input means (22-28) converts the main sound into a low-level electric signal. Therefore, by subtracting the main sound electric signal generated by the sub sound input means (22 to 28) from the main sound electric signal generated by the main sound input means (21), the main sound component in the output sound signal is reduced. Level drop and waveform disturbance are reduced. Conversely, the level of the noise component decreases. Also, since the adaptive filter includes delay means, its output lags behind its input. In response to the delay time of the delay means, when noise arrives at the auxiliary sound input means (22 to 28) and reaches the main sound input means (21), the output corresponding to the noise is output by the adaptive filter. By setting the distance of the sub sound input means (22 to 28) to the main sound input means (21), the noise component in the output sound signal becomes extremely low,
The sound collection gain of the main sound is significantly higher.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

(Embodiment) FIG. 1 schematically shows the appearance of the interior of a vehicle equipped with an embodiment of the present invention. In this embodiment, there is provided a system for operating the navigation device by voice input of a driver (driver).

Referring to FIG. 1, a monitor television 13 of a navigation device is incorporated in a center console portion of a car body 10, and a navigation unit 12 as a body of the navigation device is provided in a hidden position near the navigation television. I have. The microphone array plate 11 is attached to a portion of the ceiling 14 above the driver's seat. Although not shown in the figure, a plurality of audio speakers are mounted in the vehicle.

FIG. 2 shows the microphone array plate 11 viewed from above the car.

The main input microphone 21 is mounted on the microphone array plate 11 at a position slightly closer to the windshield glass on the driver's seat side than the center thereof, that is, at a position just above the mouth of the seated driver slightly above. A plurality of sub-input microphones 22 to 28 are mounted at a predetermined pitch around the microphone 21 on the same circumference surrounding the microphone 21. Originally, it is preferable to arrange another sub input microphone between the sub input microphones 22 and 28 and to arrange the sub input microphones symmetrically with respect to the main input microphone 21 in the front, rear, left, right, and oblique directions. But,
Since the auxiliary input microphones 22 and 28 are near the right end of the vehicle compartment and there is no space for disposing the another auxiliary input microphone, these devices are omitted. Reference numeral 29 in the figure denotes microphone codes of the microphones 21 to 28.

3a, 3b, and 3c show the positional relationship between the driver's head and the microphone when the driver is sitting in the driver's seat. FIG. 3a is a view from the front of the car, and FIG. Figure 3b is a view from the side of the car, and Figure 3c is a view from above the car. The arrow shown in FIG. 3c indicates the directivity direction of the sub input microphone. The main input microphone 21 has directivity downward in the vertical direction, while the sub input microphones 22 to 28
Has directivity in a direction opposite to the direction toward the main input microphone 21.

The microphone array board 11 is mounted on the ceiling 14 of the car 10 such that the main input microphone 21 is located just above and slightly in front of the driver's head. That is, the distance between the driver's mouth (sound source) and the main input microphone 21 is shorter than the distance between the driver's mouth (sound source) and the sub input microphones 21 to 28.

By arranging the main input microphone 21 and the sub input microphones 22 to 28 in this manner, the driver's voice
To the main input microphone 21 earlier than reaching any one of.

FIG. 4 shows a main input microphone 21 and sub input microphones 22 to 28.
2 shows the configuration of the noise canceling unit 100 connected to. This noise canceling unit 100, when any of the sub-input microphones 22 to 28 has an input to the main input microphone 21 earlier, transmits a signal from the main input microphone 21 to the voice recognition unit 200 connected to the next stage. To communicate.

Hereinafter, the configuration and operation of the noise canceling unit 100 will be described with reference to FIG.

The respective acoustic signals output by the input microphones 21 to 28 are supplied to A through the band-pass filters 31 to 38 and the AMPs 41 to 48.
The signal is input to the / D converter 50, where it is A / D converted. Of the converted signals, only the signals from the sub input microphones 22 to 28 are sent to the adaptive filters 62 to 68.

Each of the adaptive filters 62 to 68 includes a 127-stage delay element (Z ^-1 : delay element), a 128-stage variable amplification element (A _{1 to} A ₁₂₈ : multiplier) and a 127-stage addition element (adder). include and is, by adjusting the coefficients to be set in each of the variable amplification factors a ₁ to a _128, the characteristics of the filter can be variously changed.

Coefficient control circuit 62a~68a the output of the subtractor 70, i.e. the difference, between the signal yk ₂ ~Y k ₈ the primary input adapting signal from the microphone 21 and dk out A / D conversion filter 62-68 is outputted as input, the mean square value generates a coefficient set that minimizes, to apply them to each of the variable amplification factors a ₁ to a _128.
That is, the gain of each amplification element is controlled so that the output from the subtractor 70 is minimized. In this example, the coefficient control circuit
62a to 68a execute a known algorithm.

By the way, the signals output from each input microphone have different time and amplitude. This difference can be eliminated by passing the signals input to the sub input microphones 22 to 28 through the adaptive filters 62 to 68. However, the main input microphone 21
Since the output line does not pass through an adaptive filter, a delay circuit, or the like, sound input earlier than input to any of the sub-input microphones 22 to 28 directly reaches the next-stage speech recognition unit 200 as it is. .

The output components of the main input microphone 21 corresponding to the output components of the sub input microphones 22 to 28 are obtained by subtracting the output of the adaptive filters 62 to 68 from the output of the main input microphone 21 by the subtractor 70.
The speech recognition unit 200 is not substantially provided. That is, noise from outside (outside the circular area formed by the arrangement of the sub-input microphones 22 to 28) is input to any of the sub-input microphones 22 to 28 without being affected by fixed noise or moving noise. Later, it is input to the main input microphone 21. In the noise cancellation unit 100, the sub input microphones 22 to 28
Is delayed by the adaptive filters 62 to 68 and matches the output timing of the main input microphone 21. With regard to noise, a circuit operates so that the signals input from the microphones 21 to 28 are canceled out. Therefore, sound (noise) input to the sub input microphones 22 to 28 prior to the main input microphone 21 is not substantially output to the speech recognition unit 200.

As described above, only the voice signal of the driver is substantially extracted by the arrangement of the primary and secondary microphones and the noise canceling unit 100 and output to the voice recognition unit 200. The voice recognition unit 200 executes a known algorithm to recognize a voice issued by the driver, and furthermore, recognizes the recognized voice information and a command word related to predetermined navigation (for example, a display word related to display of a road map, It determines whether there is a match with each of (enlargement, contraction, sound, off, up, down, right, left, etc.), and if so, outputs a command signal for the command word to the navigation unit 12.

Therefore, in this example, an instruction can be given to the navigation unit 12 and controlled by the voice input of the driver.

In this embodiment, the coefficient control of the adaptive filter is executed by the LMS algorithm. However, another algorithm such as a learning identification method may be used.

Further, in the present embodiment, the sub input microphone is arranged on a plane, but is located at a position farther than the main input microphone from the sound generation source, and is arranged in a shape surrounding the main input microphone,
A three-dimensional arrangement may be used.

Further, in the above embodiment, the sound generated by the driver is collected on the vehicle. However, the sound collection target is not limited to the sound, and may be, for example, the operation sound of the monitored machine for monitoring the operation state of the machine. You may.

〔The invention's effect〕

As described above, according to the present invention, moving noise including fixed noise coming from a certain direction is sufficiently reduced, and only sound emitted from a sound source to be collected can be clearly extracted.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the external appearance of the interior of a vehicle equipped with an embodiment of the present invention. FIG. 2 is a top view showing the arrangement of microphones on the microphone array plate 11 shown in FIG. FIG. 3a is a front view showing the relationship between the microphone array board 11 shown in FIG. 1 and the position of the head of the driver in the car shown in FIG. 1, FIG. 3b is a side view, and FIG. FIG. 11 is a top view showing the directivity direction of the microphone on 11; FIG. 4 shows a noise canceling unit 10 connected to the microphones of the microphone array plate 11 shown in FIG.
FIG. 3 is a block diagram showing a configuration of 0. 10: Car body, 11: Microphone array board 12: Navigation unit, 13: Monitor TV 14: Ceiling 21: Main input microphone (main sound input means) 22-28: Sub input microphone (sub sound input means) 29: Microphone code , 31-38: band pass filter 41-48: amplifier, 50: A / D converter 62-68: adaptive filter, 62a-68a: coefficient control circuit 70: subtractor 100: noise canceling unit (signal processing means) 200: Voice recognition unit

Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI H04R 3/00 320 H04R 3/00 320 (56) References JP-A-61-264997 (JP, A) JP-A-2-86397 (JP, A) JP-A-62-123899 (JP, A) JP-A-58-49994 (JP, A) JP-A-57-177539 (JP, U) JP-A-58-122362 (JP, U) Patent 2861011 (JP, A) , B2) Patent 2544173 (JP, B2) Japanese Patent Publication No. 62-21377 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) G10L 3/02 H04R 1/40 H04R 3/00 B60R 16/02

Claims (2)

(57) [Claims] 1. A main sound input means which is located near a sound source to be collected and converts sound into an electric signal, and a plurality of sub sound input means which converts sound into an electric signal. An array plate in which the plurality of sub-sound input means are distributed around the center, and an electric signal generated by the sub-sound input means is substantially eliminated from an electric signal generated by the main sound input means. A sound signal processing unit that outputs a sound signal. 2. The main sound input means has directivity toward a sound source to be input; the secondary sound input means has directivity in a direction opposite to the direction toward the main sound input means; The processing means includes: an adaptive filter that generates an electric signal that substantially reduces the difference between the electric signal generated by the main sound input means and the electric signal generated by the sub sound input means; and an electric signal generated by the main sound input means. And subtracting means for outputting an acoustic signal obtained by reducing the electric signal generated by the adaptive filter.
A sound collector as described.