JPH02274007A - Car audio device with alarm sound detecting function - Google Patents

Abstract

PURPOSE:To quickly cope with an emergency vehicle by identifying an alarm sound of the outside of a car by comparing features of a sound signal outputted from a filter and an alarm sound stored in a memory in advance, and eliminating or attenuating the sound volume of a car audio device. CONSTITUTION:A car outside voice of an automobile is detected by a microphone 11, and a prescribed band component contained in the detected voice is extracted by a filter 12b. Subsequently, an alarm sound of the outside of a car is identified by comparing features of a sound signal outputted from the filter 12b and an alarm sound stored in a memory 12f in advance, and by identifying the alarm sound, the sound volume of a car audio device is eliminated or attenuated. In such a way, even if a car audio is reproduced by a large sound volume, a driver can surely recognize the generation of an alarm sound.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a car audio device with an alarm sound detection function,
Particularly related to a device that detects warning sounds such as sirens emitted from police cars and ambulances outside the vehicle and notifies the driver.6 <Prior art> When driving with the windows closed and the car audio playing at high volume, the audio This masks the sounds from outside the car.

<Problem to be solved by the invention> Therefore, in such a situation, the driver does not notice the siren or other alarm sound coming from a police car or an ambulance, and -
There was a problem that response measures such as stopping the vehicle were delayed and caused inconvenience to the emergency vehicle concerned.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a car audio device with an alarm sound detection function that allows a driver to reliably recognize the occurrence of an alarm sound even when the car audio is being played at a high volume.

Means for Solving the Problems> In the present invention, the above problems are solved by providing a microphone for detecting sound outside the vehicle, a filter for passing a predetermined band component included in the detected sound, and a sound signal output from the filter. This is achieved by an alarm sound identification unit that identifies an alarm sound outside the vehicle by comparing the characteristics of the alarm sound stored in a memory in advance, and a volume adjustment unit that reduces the volume of the car audio to zero or attenuates based on the alarm sound identification.

Function> The sound outside the car is detected by a microphone, a predetermined band component included in the detected sound is extracted by a filter, and the characteristics of the sound signal output from the filter and the alarm sound stored in the memory in advance are compared. The alarm sound outside the vehicle is identified by comparison, and the volume of the car audio device is reduced to zero or attenuated based on the identification of the alarm sound.

<Embodiment> The figure is a block diagram of a car audio device with an alarm sound detection function according to the present invention.

In the figure, 11 is a microphone for detecting sounds from outside the vehicle. When an emergency vehicle such as a police car or an ambulance is in front of the car, the flashing light can be easily recognized visually, so it can be installed, for example, on the back of the back license plate so that the alarm sound from the rear can be detected. It will be done.

12 is an alarm sound recognition unit, which includes a microphone amplifier 12a, a bandpass filter (BPF) 12b that passes a predetermined band component included in the sound detected by the microphone 11,
Filter bank 12c and analog/digital converter (
It has an AD converter) 12d, a digital signal processor (DSP) 12e, a memory 12f, and the like.

Police cars emit a siren sound by sweeping a sound between 300 Hz and 1000 Hz from low frequency to high frequency.
Ambulances generate 700 Hz to 800 Hz
The siren sound (peepo, beep) is generated by switching between the two sounds in between. For this reason, the bandpass filter 12b has a band of 300 Hz to 1000 Hz, and cuts sounds other than the siren frequency, such as environmental sounds such as engine sounds and noise, to prevent misrecognition.

Characteristics ALSD of various alarm sounds are set in advance in the memory 12f. Note that the process of setting the characteristics ALSD of various alarm sounds in the memory involves sampling these alarm sounds at a predetermined period T for a certain period of time, and calculating several frequencies f included in each sampled alarm sound.

f,, f□260. This is done by knowing the levels of the components, normalizing them, and storing them in memory. In addition to the above features of the alarm sound, the memory 12f stores audio data ALMS for an alarm sound detection message that is output by voice synthesis when the alarm sound is detected.

The filter puncture 12c has a predetermined frequency f, f2゜f3j
Several bandpass filters B Fl, B F,, B F3. which pass only '@'@* components. ..., each frequency component is sent to the next stage A at every predetermined sampling period T.
Corresponding AD converter AD engineer, AD2. of D converter 12d. A.D.
3. Enter in...

13 is a DA converter that converts digital audio data (alarm sound detection message) inputted from the DSP 12e when an alarm sound is detected into analog sound; 14 is a microcomputer;
Reference numeral 5 denotes a display section, and alarm sounds are detected by these 11 to 15.

Also, in the figure, 21 to 23 are radio tuners, respectively.
Audio sources such as tape players and CD players,
24 is a source switching unit, 25 is a volume for adjusting the volume,
26 is a mute circuit that blocks the output of audio sound;
Reference numeral 27 is a signal switching section for switching between the audio system and the alarm sound detection message system, 28 is an amplifier, 29 is a speaker, and 21 to 29 indicate the main parts of the audio device.

The sound outside the vehicle detected by the microphone 11 is input to the bandpass filter 12b, and only the siren frequency component included in the sound outside the vehicle passes through the bandpass filter and is input to the filter puncture 12c. The filter bank 12c extracts each frequency f from the input signal every time the sampling signal SP is generated from the DSP 12e.
* Extract the + component and send it to the subsequent AD converter 12d.
The AD converter converts the input signal into digital data.

The DSP 12e converts the AD converter 1 every sampling period T.
The level of each frequency f□j Lj fJj *6 m component is taken in from 2d, normalized, and compared with the frequency level of each alarm sound stored in advance in the memory 12f to identify the alarm sound. Note that the warning sound identification process is performed in the same manner as the well-known voice recognition process.

After identifying the alarm sound through the above processing, the DSP 12e outputs an alarm sound identification signal and sends an alarm sound detection message (
Audio data) ALMS is read from the memory 12f and output to the DA converter 13 at the subsequent stage.

When the alarm sound identification signal ALD is generated, the mute circuit 26 blocks the audio signal and makes its output zero, and the signal switching section 27 operates to select the signal from the DA converter 13. As a result, the audio sound disappears, and instead, an alarm sound detection message converted into analog sound by the DA converter 13 and a message informing the type of the source of the alarm sound (police car, ambulance, etc.) are sent to the speaker via the amplifier 28. 29, and in parallel with the above, the microcomputer 14 displays on the display 15 the fact that an alarm sound has been detected and the type of source of the alarm sound (police car, ambulance, etc.).

Although the case where the audio sound is reduced to zero upon detecting the alarm sound has been described above, the output level may be attenuated to such an extent that the alarm sound outside the vehicle can be heard.

Furthermore, in the above description, the case is explained in which the audio sound is controlled and the driver is notified of the detection of the warning sound audibly by voice synthesis or visually by display means.
It may be configured such that only the audio sound is attenuated without providing notification by sound or display.

<Effects of the Invention> According to the present invention, external sounds of a car are detected by a microphone, a predetermined band component included in the detected sound is extracted by a filter, and the sound signal output from the filter is stored in a memory in advance. It is configured to compare the characteristics of stored alarm sounds to identify the alarm sound outside the car, and to zero or attenuate the volume of the car audio system based on the identification of the alarm sound. Even when the alarm sound is being played back, the alarm sound can be detected reliably, allowing quick response and avoiding causing trouble to emergency vehicles.

[Brief explanation of drawings]

The figure is a block diagram of a car audio device with an alarm sound detection function according to the present invention. 11...Microphone 12...Alarm sound recognition unit 12b...Band pass filter 12e...Digital signal processor 26...Mute circuit

Claims (1)

[Claims] A microphone for detecting sounds outside the vehicle; a filter for passing predetermined band components included in the detected sounds; 1. A car audio device with an alarm sound detection function, comprising: an alarm sound identification section that identifies alarm sounds outside the vehicle by comparing characteristics; and a volume adjustment section that zeroes or attenuates the volume of the car audio based on the alarm sound identification.