JP2003281678A - Accident sound detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To discriminate repetitive impact sounds which have been hitherto undiscriminable, such as motorbike passing sounds, and to efficiently detect only accident sounds to improve the ability of detecting such accident sounds. <P>SOLUTION: This accident sound detecting device for detecting accident sounds using a sound signal from the external comprises an accident sound acquiring means 20 for acquiring an accident sound, a repetitive impact sound determining/computing means 30 for determining from an output signal from this accident sound acquiring means 20 whether the accident sound is a repetitive impact sound, and a repetitive impact sound removing means 40 for removing the repetitive impact sound from the accident sound acquired by the accident sound acquiring means 20 in the case where the determination result of this repetitive impact sound determining/computing means 30 shows that the sound is a repetitive impact sound. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accident for efficiently detecting only an accident sound from traffic sounds at an intersection or the like, accident sounds (including accident sounds such as collisions and sudden braking sounds leading to accidents). The present invention relates to a sound detecting device.

[0002]

2. Description of the Related Art Generally, since many traffic accidents occur at intersections, a traffic accident status recording device for recording the status of accident occurrence has been conventionally considered. FIG. 10 is a block diagram showing a conventional traffic accident situation recording device disclosed in, for example, Japanese Patent Laid-Open No. 4-338900. In FIG. 10, 1 and 4 are traffic signals, 1B, 1Y, 1R, 4B, 4Y,
4R is a signal light, 2B, 2Y, 2R is a signal line, 3 is a signal light blinking device, 5 is a signal light symbol generation device, 6 is a time character generation unit, 7 is an addition unit, 8 is an imaging device, 9 is an endless recording device, 10 Is an ambient sound detection device, 11 is a collision sound detection circuit, 1
Reference numeral 2 is a recording control device, and 13 is a magnetic recording / reproducing device.

The parts that detect accident sounds are the ambient sound detection device 10 and the collision sound detection circuit 11. That is, the acoustic signal is detected by the ambient sound detection device 10 and sent to the collision sound detection circuit 11. The collision sound detection circuit 11 determines whether or not the detected acoustic signal is a collision sound of the vehicle, and when it is determined to be a collision sound, a collision sound detection signal is sent to the recording control device 12. In the collision sound detection circuit 11, it is determined whether the detected traffic sound is an accident (collision) sound by comparing the level of the input acoustic signal with a predetermined threshold value, and the level is equal to or higher than the threshold value. If it is, it is judged as an accident.
As a measure against malfunction, the ambient sound detecting device 10 uses a directional microphone and a band elimination filter in the path of the acoustic signal.

[0004]

By the way, in the collision sound detection circuit described in the above publication, the level comparison between the acoustic signal detected in the discrimination of the collision sound and a preset fixed threshold value is carried out. However, in general traffic sounds, there are many high-level sounds other than accident sounds, such as sudden braking sounds, horn sounds, and runaway sounds. Therefore, the method of performing the level comparison between the detected acoustic signal and the fixed threshold value has a problem in that, in addition to the actual accident sound, many other traffic sounds are also distinguished as accident sounds. Further, there is a problem in that no information about the type of the detected accident sound such as a collision sound or a repetitive impact sound can be obtained.

The present invention has been made in order to solve the above problems, and does not use a signal level threshold value for determining an accident sound, but normalizes a waveform of a signal including an accident sound. It is an object of the present invention to provide an accident sound detection device capable of distinguishing an impact sound having repetitiveness from an actual accident sound by improving, comparing, and binarizing the sound and improving the ability to detect the accident sound. .

[0006]

An accident sound detecting apparatus according to the invention of claim 1 is an accident sound detecting apparatus for detecting an accident sound using an external acoustic signal, and takes in the accident sound. Accident sound capturing means, repetitive impact sound determination calculating means for determining a repetitive impact sound from an output signal from the accident sound capturing means, and the determination result of the repetitive impact sound determination calculating means is repetitive. In the case of a certain impact sound, the repetitive impact sound removing means for excluding the repetitive impact sound from the accident sound captured by the accident sound capturing means is provided.

The accident sound detecting device according to the invention of claim 2 is
The accident sound capturing means includes a waveform shaping circuit that shapes the waveform of the external acoustic signal, an A / D converter that converts an analog signal of the waveform shaping circuit into a digital signal, and the A
The difference calculating means for extracting the difference signal from the output signal from the / D converter is compared with the difference signal from the difference calculating means and the reference difference value having a preset value, and the trigger signal is generated according to the comparison result. It has a comparing circuit to be generated and a switch for taking in the output signal from the A / D converter into the repetitive impact sound judgment calculating means based on the trigger signal from the comparing circuit.

The accident sound detecting device according to the invention of claim 3 is
The repetitive impact sound determination calculation means normalizes the level of the output signal from the A / D converter, and the comparison means removes a constant level signal of the signal standardized by the normalization means. And binarizing means for binarizing the output signal from the comparing means, and repetitive impact sound determining means for determining and outputting repetitive impact sound from the output signal from the binarizing means. I have.

The accident sound detecting device according to the invention of claim 4 is
When the evaluation value based on the output signal of the binarizing means is smaller than a predetermined value, the repetitive impact sound determination means determines that the accident sound captured by the accident sound capturing means is a repetitive impact sound. To do.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. Embodiment 1. 1 is a functional block diagram showing a first embodiment of the present invention. In FIG. 1, 20 is an accident sound capturing means, 100 is a sound input signal from the ambient sound detecting device 10 (see FIG. 10), 110 is an output signal of the accident sound capturing means 20, and 30 is an accident sound capturing means 20. Output signal from 110
From the output signal of the repetitive impact sound determination calculation means 30, and 40 indicates an accident based on the output signal 120 of the repetitive impact sound determination calculation means 30. Output signal 110 of sound capturing means 20
A repetitive impact sound removing means for removing a repetitive impact sound, for example, a motorcycle sound, from the repetitive impact sound removing means 40.
Is the output signal of.

FIG. 2 is a circuit configuration diagram showing an example of a specific circuit configuration of the accident sound capturing means 20. In FIG. 2, 2
Reference numeral 1 is a waveform shaping circuit that shapes the waveform of an external acoustic input signal 100, 101 is an output signal from the waveform shaping circuit 21, and 22 is for converting the output signal 101 from the waveform shaping circuit 21 from an analog signal to a digital signal. A / D
A converter, 102 is a digital output signal of the A / D converter 22, 23 is a difference calculating means for extracting a difference signal from the digital output signal 102, and 103 is a difference calculating means 23.
, A reference difference value generating circuit for generating a difference signal (reference difference value) of a reference level, 24
Compares the difference signal 103 from the difference calculating means 23 with the reference difference value from the reference difference value generating circuit 25, and outputs the output signal when the difference signal 103 from the difference calculating means 23 is larger than the set reference difference value. This is a comparison circuit for generating 104. Reference numeral 26 is a switch for capturing the output signal 102 of the A / D converter 22 by using the output signal 104 from the comparison circuit 24 as a trigger signal, and 110 is an output signal (OUT) captured by the switch 26.

FIG. 3 is a circuit configuration diagram showing an example of a specific circuit configuration of the repetitive impact sound determination calculation means 30. In FIG. 3, 31 is the output signal 11 from the accident sound capturing means 20.
A normalizing means for normalizing the level of 0, 32 is a comparing means for removing a constant level signal of the signal standardized by the normalizing means 31, 33 is a logical level for binarizing the output signal from the comparing means 32. Binarization means for separating 1 "and" 0 ", 3
Reference numeral 4 is a repetitive impact sound determination means for determining an impact sound having repetitiveness from the output signal from the binarization means 33 and outputting it as an output signal 120.

Of course, the comparing means 32 and the binarizing means 33 may be integrated to form the binarizing means 33. In this case, binarization can be realized by setting all values equal to or greater than the reference value (for example, 0.2) to "1" and all values less than that to "0".

Next, the operation will be described with reference to FIGS. First, the case of traffic sounds other than accident sounds, for example, motorcycle passing sounds, will be described with reference to FIGS. 4 to 6. Now
When an acoustic input signal 100 is generated when an accident occurs and is input to the accident sound capturing means 20, the waveform shaping circuit 21 removes an unnecessary signal component and an output signal 101 is generated.
The output signal 101 is converted from an analog signal to a digital signal 102 by the A / D converter 22. The outputted digital signal 102 is inputted to the difference calculating means 23, and the difference signal 1 of the digital output signal 102 is outputted from the difference calculating means 23.
03 is output. The differential signal 103 generally represents a change in signal level, and a larger signal level is generated as the level changes abruptly. On the contrary, if the signal level is large and the level change is small, the level is small. Therefore, when a sudden phenomenon occurs, for example, when an accident occurs, the differential signal 103 shows a large level change.

Therefore, the reference difference value generation circuit 2 is previously prepared.
5, a reference difference value serving as a reference is generated, and the comparison circuit 24
Is used to compare the difference signal 103 with the reference difference value. When the difference signal 103 is larger than the reference difference value, it is determined that a traffic accident sound whose signal level changes abruptly is generated, and the output signal 104 is generated as a trigger signal. The output signal 104 from the comparison circuit 24 turns on the switch 26 to turn on the output signal 102 of the A / D converter 22.
Is input to the repetitive impact sound determination calculation means 30 as an output signal 110.

The normalizing means 31 of the repetitive impact sound judgment calculation means 30 normalizes the level of the output signal 110 taken in, and compares the signal of the repetitive impact sound acquisition waveform as shown in FIG. 4, for example. To 32. In the comparison means 32,
A reference value is provided in order to remove a signal of a certain level, and only signals above the reference value are output, and signals below the reference value are substantially not output. That is, assuming that the reference value is 0.2 in FIG. 4, for example, signals with a level of 0.2 or more are output, and signals with a level of less than 0.2 are all 0.

FIG. 5 shows a signal waveform output by the comparing means 32 in this way, and the waveform is a waveform in which only signals having the reference value or more are left. Figure 6
6 is a patternized waveform of the waveform obtained by binarizing the waveform of FIG. 5 by the binarizing means 33. In this evaluation pattern, the evaluation value = 0.062 is the sum of the levels of “1” divided by the time width of FIG. 6, and indicates the area occupancy of the part of which the level is “1”. is there.

Next, a normal case where the traffic sound is an accident sound will be described with reference to FIGS. The normalizing means 31 of the repetitive impact sound judgment calculating means 30 normalizes the level of the output signal 110 taken in and outputs the signal of the repetitive impact sound taking waveform as shown in FIG. 7 to the comparing means 32. To do. In the comparison means 32, a reference value is provided in order to remove a signal of a constant level, and only a signal above the reference value is output, and a signal below the reference value is substantially not output. That is,
For example, assuming that the reference value is 0.2 in FIG. 7, signals with a level of 0.2 or more are output, and signals with a level of less than 0.2 are all 0.

FIG. 8 shows a signal waveform output by the comparing means 32 in this way, and the waveform is a waveform in which only signals having the reference value or more are left. Figure 9
9 is a patternized waveform of the waveform obtained by binarizing the waveform of FIG. 8 by the binarizing means 33. In this evaluation pattern, the evaluation value = 0.29 is obtained by dividing the total sum of the levels of “1” by the time width of FIG. 9, and indicates the area occupancy of the part of which the level is “1”. is there.

As can be seen from the comparison between FIG. 6 and FIG. 9, there are traffic sounds other than the accident sound shown in FIG. 6, such as a motorcycle passing sound, and the normal case where the traffic sound shown in FIG. 9 is an accident sound. Then, it is clear that there is a difference in the evaluation values, and the evaluation value is smaller in the case of a motorcycle passing sound or the like than in the normal case.

Therefore, in the repetitive impact sound judging means 34,
The output signal from the binarizing means 33 is fetched, and the evaluation value of the fetched output signal is a predetermined judgment value, for example, 0.1.
If the evaluation value of the captured output signal is smaller than a predetermined judgment value, for example, 0.1, it is determined as a repetitive impact sound, that is, a motorcycle passing sound, and the repetitive impact sound is determined. The output signal 120 is output to the removing means 40. The repetitive impact sound removing means 40 removes the output signal 110 from the accident sound capturing means 40 based on the output signal 120 at this time.

On the other hand, when the evaluation value of the output signal fetched from the binarizing means 33 is larger than a predetermined judgment value, for example, 0.1, the repetitive impact sound judging means 34 gives the repetitive shock sound. It is determined that the normal accident sound is not, and the output signal 120 is output to the repetitive impact sound removing means 40. The repetitive impact sound removing means 40 outputs the output signal 110 from the accident sound capturing means 40 as it is based on the output signal 120 at this time.

As described above, in this embodiment, in order to distinguish a repetitive impact sound from an actual accident sound in the sound signal such as an accident sound, the standard of the level of the signal is taken. The comparison is performed to eliminate the signal of a certain level, the comparison result is binarized, the impact sound with repetitiveness is determined, and the accident sound captured based on the determination result is reproducible. Since the impact sound is removed, it is possible to identify a motorcycle passing sound, etc., which could not be identified up to now, and it is possible to efficiently detect only the accident sound and improve the ability to detect the accident sound.

[0024]

As described above, according to the first aspect of the invention, there is provided an accident sound detecting device for detecting an accident sound by using an acoustic signal from the outside, wherein the accident sound is taken in. The sound capturing means, the repetitive impact sound determination calculating means for determining a repetitive impact sound from the output signal from the accident sound capturing means, and the determination result of the repetitive impact sound determining operation means is repetitive. In the case of a certain impact sound, since the repetitive impact sound removing means for excluding the repetitive impact sound from the accident sound captured by the accident sound capturing means is provided, for example, a motorcycle which cannot be identified until now. It is possible to identify repetitive impact sounds such as passing sounds, and it is possible to efficiently detect only accident sounds and improve the ability to detect accident sounds.

According to a second aspect of the present invention, the accident sound capturing means includes a waveform shaping circuit for shaping the waveform of the external acoustic signal, and an analog signal of the waveform shaping circuit converted into a digital signal. And a difference calculation means for extracting a difference signal from an output signal from the A / D converter, a difference signal from the difference calculation means, and a reference difference value having a preset value. A comparison circuit for generating a trigger signal according to the comparison result, and a switch for fetching the output signal from the A / D converter into the repetitive impact sound judgment calculation means based on the trigger signal from the comparison circuit. Since it has, there is an effect that it can contribute to efficiently detecting only the accident sound.

According to a third aspect of the present invention, the repetitive impact sound judgment calculating means is a normalizing means for normalizing the level of the output signal from the A / D converter, and the normalizing means. A comparing means for removing a constant level signal of the standardized signal, a binarizing means for binarizing the output signal from the comparing means, and an impact sound having repetitiveness from the output signal from the binarizing means. Since it has a repetitive impact sound determination means for determining and outputting, there is an effect that it is possible to identify repetitive impact sound and contribute to improvement of accident sound detection capability.

Further, according to the invention of claim 4, the repetitive impact sound judging means takes in the accident sound taking means when the evaluation value based on the output signal of the binarizing means is smaller than a predetermined value. Since the accident sound is determined to be a repetitive impact sound, there is an effect that the repetitive impact sound can be efficiently and reliably determined.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing an example of accident sound capturing means according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing an example of repetitive impact sound determination calculation means according to the first embodiment of the present invention.

FIG. 4 is a diagram showing output waveforms of traffic sounds other than accident sounds by the standardizing means in the first embodiment of the present invention.

FIG. 5 is a diagram showing output waveforms of traffic sounds other than accident sounds of the comparison means in the first embodiment of the present invention.

FIG. 6 is a diagram showing output waveforms of traffic sounds other than accident sounds of the binarizing means in the first embodiment of the present invention.

FIG. 7 is a diagram showing a normal output waveform which is an accident sound of the normalizing means in the first embodiment of the present invention.

FIG. 8 is a diagram showing an output waveform at a normal time, which is an accident sound of the comparison means in the first embodiment of the present invention.

FIG. 9 is a diagram showing an output waveform at a normal time which is an accident sound of the binarizing means in the first embodiment of the present invention.

FIG. 10 is a block diagram showing a conventional traffic accident situation recording device.

[Explanation of symbols]

20 means for capturing accident sound, 21 waveform shaping circuit, 22 A /
D converter, 23 difference calculation means, 24 comparison circuit, 25
Reference difference value generation circuit, 26 switch, 30 repetitive impact sound determination calculation means, 31 standardization means, 32 comparison means, 33 binarization means, 34 repetitive impact sound determination means,
40 Repetitive impact sound removing means.

Claims (4)

[Claims] 1. An accident sound detection device for detecting an accident sound using an acoustic signal from the outside, comprising: accident sound capturing means for capturing the accident sound; and an output signal from the accident sound capturing means. Repeatable impact sound determination calculation means for determining a repeatable impact sound from the above, and if the determination result of the repeatable impact sound determination calculation means is a repeatable impact sound, an accident captured by the accident sound capture means An accident sound detection device comprising: a repetitive impact sound removing means for excluding the repetitive impact sound from a sound. 2. The accident sound capturing means includes a waveform shaping circuit for shaping the waveform of the external acoustic signal, and an A / D for converting an analog signal of the waveform shaping circuit into a digital signal.
A converter, a difference calculation means for extracting a difference signal from an output signal from the A / D converter, a difference signal from the difference calculation means and a reference difference value having a preset value are compared, and the comparison result is obtained. And a comparator circuit for generating a trigger signal according to
The accident sound detecting apparatus according to claim 1, further comprising a switch for taking the output signal from the D converter into the repetitive impact sound judgment calculating means. 3. The repetitive impact sound judgment calculation means is a normalization means for normalizing the level of the output signal from the A / D converter, and a constant level signal of the signal standardized by the normalization means. And a binarizing unit that binarizes the output signal from the comparing unit, and a repetitive impact that determines and outputs a repetitive impact sound from the output signal from the binarizing unit. The accident sound detection device according to claim 2, further comprising sound determination means. 4. The repetitive impact sound judging means, when the evaluation value based on the output signal of the binarizing means is smaller than a predetermined value, the accident sound captured by the accident sound capturing means has a repetitive impact. 4. It is determined that the sound is a sound.
Accident sound detector described.