JP2950771B2 - Accident sound detection circuit and accident sound detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accident sound detection circuit for effectively detecting a traffic accident from an accident sound at an intersection or the like (including an accident sound such as a collision and a sudden braking sound leading to an accident). The present invention also relates to an accident sound detection device comprising a plurality of accident sound detection circuits.

[0002]

2. Description of the Related Art In general, traffic accidents frequently occur at intersections. Therefore, traffic accident situation recording devices for recording the situation at the time of occurrence of an accident have been proposed. FIG. 10 is a block diagram of a conventional traffic accident situation recording device disclosed in, for example, Japanese Patent Application Laid-Open No. 4-338900. 10, 1 and 4 are traffic lights, 1B, 1Y, and 1R are signal lights, 1b, 1y, and 1r are signal light lighting symbols, 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, 12 is a recording control device, and 13 is a magnetic recording / reproducing device.

Here, the parts that detect traffic noise are an ambient sound detection device 10 and a collision sound detection circuit 11. That is, the acoustic signal is saved 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 input acoustic signal is a vehicle collision sound. When the collision detection circuit 11 determines that the collision sound is a collision sound, the collision sound detection signal is sent to the recording control device 12. The collision sound detection circuit 11 determines whether or not the detected traffic sound is an accident (collision) sound by comparing the level of the input acoustic signal with a predetermined threshold, and determining that the level is equal to or greater than the threshold. If it becomes, it is judged as an accident.
As a countermeasure against malfunction, a directional microphone is used for the ambient sound detection device 10 and a band elimination filter is provided in the path of the acoustic signal.

[0004]

The traffic sound detector described in the above publication compares the level of an acoustic signal detected for discrimination of a collision sound with a predetermined fixed threshold value. However, in general traffic sounds, there are many loud sounds other than accident sounds, such as slow brake sounds, horn sounds, and runaway sounds. Therefore, in the method of performing the level comparison between the detected sound signal and the fixed threshold, there is a problem that in addition to the actual accident sound, many other traffic sounds are simultaneously determined as the accident sound. . In addition, there is also a problem that no information regarding the type of the detected accident, whether it is a collision sound or a sudden braking sound, can be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and uses a threshold value which varies according to a change in the level of an input audio signal as a reference signal instead of fixing the threshold value. Thus, an object of the present invention is to provide an accident sound detection circuit for efficiently detecting an accident sound. It is another object of the present invention to provide an accident sound detection device capable of discriminating information on the type of accident by subjecting an input acoustic signal to signal processing while limiting a frequency band.

[0006]

According to a first aspect of the present invention, there is provided an accident sound detection circuit for detecting an accident sound using an acoustic signal from an ambient sound detection device disposed near an intersection or a road. A detection circuit, a waveform shaping circuit for shaping the waveform of an acoustic signal from an ambient sound detection device, and a reference signal for performing moving average processing and bias level adjustment on one of the branched signals from the waveform shaping circuit Generating means; delay adjusting means for delaying the other signal output from the reference signal generating means by delaying the other signal branched from the waveform shaping circuit; and adjusting the output and delay of the reference signal generating means. And a comparing means for comparing the output of the means and generating an accident sound detection signal in accordance with the result of the comparison.

The accident sound detection circuit according to the second aspect of the present invention comprises:
In the invention of claim 1, the comparing means generates an accident sound detection signal when a signal from the delay adjusting means is larger than a signal from the reference signal generating means.

An accident sound detection circuit according to a third aspect of the present invention comprises:
3. The invention according to claim 1, wherein the reference signal generating means performs a first A / D conversion on an output of the waveform shaping circuit, and a moving average for obtaining a moving average of the output of the A / D converter. Circuit, a bias signal generator for generating a bias signal, and an adder for adding the output of the moving average circuit to the output of the bias signal generator. A second A / D converter for converting the data, and a delay adjusting circuit for delaying the output of the A / D converter, wherein the comparing means converts the output of the delay adjusting circuit into a first D / A signal; It has an A converter, a second D / A converter for D / A converting the output of the adder, and a comparator for comparing the outputs of the first and second D / A converters.

An accident sound detection circuit according to a fourth aspect of the present invention comprises:
According to the third aspect of the present invention, the first and second A / D converters are shared.

An accident sound detection circuit according to a fifth aspect of the present invention comprises:
According to the third or fourth aspect of the present invention, the first D / A converter is provided before the adder.

An accident sound detection device according to a sixth aspect of the present invention comprises:
A plurality of accident sound detection circuits according to any one of claims 1 to 5, wherein the plurality of accident sound detection circuits are connected in parallel to an input acoustic signal, and each of them is restricted to a different frequency band. An accident sound discriminating means for judging an accident sound from the accident sound detection signal to generate a final accident sound detection signal.

An accident sound detection device according to a seventh aspect of the present invention comprises:
In the invention according to claim 6, the accident sound discriminating means is a logical operation circuit for judging an accident sound by performing arithmetic processing on the accident sound detection signals from the plurality of accident sound detection circuits.

The accident sound detection device according to the invention of claim 8 is:
In the invention of claim 6, the accident sound discriminating means is a pattern comparing means for judging an accident sound by comparing a pattern of an accident sound detection signal from a plurality of accident sound detection circuits with a preset pattern.

According to a ninth aspect of the present invention, there is provided an accident sound detecting apparatus.
In the invention according to claim 8, the pattern comparing means comprises a pattern comparing circuit and a pattern signal generator for generating a predetermined pattern.

[0015]

An embodiment of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a block diagram showing Embodiment 1 of the present invention. In the figure, 11A is an accident sound detection circuit, 50 is, for example, a high-pass circuit, a band-pass circuit circuit, or the like.
A waveform shaping circuit to which an acoustic signal 100 from the waveform shaping circuit (see FIG. 10) is supplied.
Rectifier circuit for extracting a positive signal out of 0, 52a, 5
2b is an A for converting an analog signal from the waveform shaping circuit 50 and a rectifying circuit 51 into a digital signal, respectively.
/ D converter 53, A / D as a second A / D converter
This is a delay adjustment circuit that delays the digital signal from the converter 52a.

Reference numeral 54 denotes a moving average circuit for moving and averaging the digital signal from the A / D converter 52b as a first A / D converter, and 55 denotes an output signal from the moving average circuit 54 and a bias signal generator. Adders 57a and 57b for adding the bias signals from 56 are delay adjustment circuits 5
3 and a D / A converter for converting an output signal from the adder 55 from a digital signal to an analog signal, and 58 is an output signal (analog signal) from a D / A converter 57a as a first D / A converter. A signal) 130a and a moving average from a D / A converter 57b as a second D / A converter and an output signal (analog signal) 130b as a fluctuating reference signal after bias adjustment, which is a comparator. The output signal from the comparator 58 is output to the outside as an accident sound detection signal 140.

The A / D converter 52b, the moving average circuit 54, the adder 55 and the bias signal generator 56 constitute reference signal generating means, and the A / D converter 52a and the delay adjusting circuit 53 constitute delay adjusting means. And the D / A converter 5
7a, 57b and the comparator 58 constitute comparison means.

Next, the operation will be described with reference to FIG. Now, when an acoustic signal 100 as shown in FIG. 2A is input from an external ambient sound detection device to the waveform shaping circuit 50, unnecessary signal components are removed here. Note that FIG.
The acoustic signal 100 shown in (a) shows a case where an accident has occurred and a sharp peak has occurred in the waveform at point A or point B, for example. The output signal 110 whose waveform has been shaped by the waveform shaping circuit 50 is split into two, one of which is supplied to the rectifier circuit 51, where only the positive component is extracted. The output signal containing only the positive component extracted by the rectifier circuit 51 is further converted from an analog signal into a digital signal by an A / D converter 52b, and then supplied to a moving average circuit 54, where the moving average processing is performed. Then, an average level signal 120 in a short time as shown in FIG. 2B is obtained. The average level signal 120 from the moving average circuit 54 is added to the bias signal from the bias signal generator 56 by the adder 55, and after a continuous bias adjustment is performed, the signal is passed through the D / A converter 57b. The reference signal 130b fluctuates after the bias level adjustment as shown in FIG.

On the other hand, the other signal branched from the waveform shaping circuit 50 is converted to a digital signal by an A / D converter 52a, and then sent to a delay adjusting circuit 53. The delay adjustment circuit 53 performs an appropriate delay processing on the input digital signal, and outputs the output signal to the D / A converter 57.
2A, the comparator 58 outputs the signal 130a as shown in FIG.
Is entered as The comparator 58 performs a level comparison between the input signal 130a and the reference signal 130b, and if the level of the input signal 130a is higher than the level of the reference signal 130b, an accident sound as shown in FIG. Detection signal 14
Generates 0.

That is, in FIG. 2B, the signal 130a obtained through the delay adjustment circuit 53 and obtained at the output side of the D / A converter 57a is output from the D / A converter 57b at points A and B. Bias level adjusted reference signal 13 obtained on output side
0b, the level is higher than that of FIG.
As shown in (c), the accident sound detection signal 140 is reliably generated from the comparator 58 at points A and B, and the occurrence of an accident can be detected.

The output signal of the moving average circuit 54, that is, the average level signal 120 whose bias level is not adjusted
And a signal 130a obtained on the output side of the D / A converter 57a
Are compared, the level of the signal 130a is
As can be seen from FIG. 2B, there are several points other than the points A and B, which may cause the accident sound detection signal 140 to be generated. However, as described above, in the present embodiment, the bias signal from the bias signal generator 56 is added to the average level signal 120 to adjust the bias level, and then the reference signal 130b is increased substantially by a predetermined amount. Is formed, and the reference signal 130b is compared with the signal 130b. Therefore, the accident sound detection signal 14 is reliably output from the comparator 58 only at points A and B.
0 is generated, and the occurrence of an accident can be detected. Thus, in the present embodiment, the accident sound can be reliably detected without being affected by the level of the input acoustic signal.

Embodiment 2 FIG. FIG. 3 is a block diagram showing Embodiment 2 of the present invention. 3, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. In FIG. 1, two A / D converters are used, whereas in the present embodiment, the A / D converters are shared,
In addition, a digital rectifier circuit is used. In the figure, 11B is an accident sound detection circuit, 52 is a waveform shaping circuit 50
Is an A / D converter for converting an analog signal from the digital camera into a digital signal. Other configurations are the same as those in FIG.

Next, the operation will be described. Now, the acoustic signal 100 is output from the external ambient sound detecting device to the waveform shaping circuit 50.
, Unnecessary signal components are removed here.
The output signal whose waveform has been shaped by the waveform shaping circuit 50 is converted from an analog signal into a digital signal by the A / D converter 52 and extracted as an output signal 111.
One is supplied to the rectifier circuit 51, where only the positive component is extracted. The output signal including only the positive component extracted by the rectifier circuit 51 is further supplied to a moving average circuit 54, in which a moving average process is performed to obtain an average level signal 120 in a short time. The average level signal 120 from the moving average circuit 54 is added to the bias signal from the bias signal generator 56 by the adder 55, and after a continuous bias adjustment is performed, the bias is passed through the D / A converter 57b. Fluctuating reference signal 130 after level adjustment
It is sent to the relative softener 58 as b.

On the other hand, the other signal branched from the A / D converter 52 is sent to a delay adjusting circuit 53. The delay adjustment circuit 53 performs an appropriate delay processing on the input digital signal, and outputs the output signal to the D / A converter 57a.
, Is input to the comparator 58 as the signal 130a at the same timing as the above-described reference signal 130b. The comparator 58 performs a level comparison between the input signal 130a and the reference signal 130b, and generates an accident sound detection signal 140 if the level of the input signal 130a is higher than the level of the reference signal 130b.

In FIG. 3, the output signal of the waveform shaping circuit 50 is subjected to A / D conversion, and then rectification and moving average processing are performed. It is exactly the same, and the occurrence of an accident can be detected as in the case of FIG. Thus, also in the present embodiment, the accident sound can be reliably detected without being affected by the level of the input acoustic signal.

Embodiment 3 FIG. 4 is a block diagram showing a third embodiment of the present invention. 4, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. In FIG. 1, the output of the moving average circuit 54 is D / A-converted in the subsequent stage of the adder 55, whereas in the present embodiment, the output is performed in the preceding stage of the adder 55. In the figure,
11C is an accident sound detection circuit, which is a D / A converter 57b.
Is provided between the moving average circuit 54 and the adder 55. Other configurations are the same as those in FIG.

Next, the operation will be described. Now, the acoustic signal 100 is output from the external ambient sound detecting device to the waveform shaping circuit 50.
, Unnecessary signal components are removed here.
The output signal 1 whose waveform has been shaped by the waveform shaping circuit 50
10 is branched into two, and one is supplied to a rectifier circuit 51, where only a positive component is extracted. The output signal containing only the positive component extracted by the rectifier circuit 51 further includes an A / D
After being converted from an analog signal to a digital signal by the converter 52b, it is supplied to the moving average circuit 54, where the moving average processing is performed, and the average level signal 120 in a short time is obtained. Average level signal 12 from moving average circuit 54
0 is converted from a digital signal to an analog signal by a D / A converter 57b and supplied to an adder 55, where it is added to a bias signal from a bias signal generator 56, and a continuous bias adjustment is performed. Thereafter, the reference signal 130b is sent to the softener 58 as a fluctuating reference signal 130b after the bias level adjustment.

On the other hand, the other signal branched from the waveform shaping circuit 50 is converted to a digital signal by the A / D converter 52a, and then sent to the delay adjusting circuit 53. The delay adjustment circuit 53 performs an appropriate delay processing on the input digital signal, and outputs the output signal to the D / A converter 57.
After passing through a, the signal is input to the comparator 58 as the signal 130a at the same timing as the above-described reference signal 130b. The comparator 58 performs a level comparison between the input signal 130a and the reference signal 130b, and generates an accident sound detection signal 140 if the level of the input signal 130a is higher than the level of the reference signal 130b.

In FIG. 4, the signal subjected to the moving average processing is D / A converted, and then the bias is adjusted. The signal waveform input to the comparator 58 is exactly the same as that in FIG. The occurrence of an accident can be detected in the same manner as in FIG. Thus, also in the present embodiment, the accident sound can be reliably detected without being affected by the level of the input acoustic signal.

Embodiment 4 FIG. FIG. 5 is a block diagram showing a fourth embodiment of the present invention. In FIG. 5, FIG.
3 and 4 are denoted by the same reference numerals, and detailed description thereof will be omitted. In FIG. 1, two A / D converters are used, whereas in the present embodiment, the A / D converter is shared and a digital rectifier circuit is used. In addition, in FIG. 1, the output of the moving average circuit 54 is D / A-converted in the subsequent stage of the adder 55, whereas in the present embodiment, the output is performed in the preceding stage of the adder 55. That is, the present embodiment is a case where the second and third embodiments are substantially combined. In the figure, 11D is an accident sound detection circuit. Other configurations are the same as those in FIGS. 1, 3, and 4.

Next, the operation will be described. Now, the acoustic signal 100 is output from the external ambient sound detecting device to the waveform shaping circuit 50.
, Unnecessary signal components are removed here.
The output signal whose waveform has been shaped by the waveform shaping circuit 50 is converted from an analog signal into a digital signal by the A / D converter 52 and extracted as an output signal 111.
One is supplied to the rectifier circuit 51, where only the positive component is extracted. The output signal including only the positive component extracted by the rectifier circuit 51 is further supplied to a moving average circuit 54, in which a moving average process is performed to obtain an average level signal 120 in a short time. The average level signal 120 from the moving average circuit 54 is supplied to the D / A converter 57
b, the digital signal is converted into an analog signal and supplied to the adder 55, where it is added to the bias signal from the bias signal generator 56, and after a continuous bias adjustment is performed, the D / A converter 57b Is sent to the softening device 58 as a fluctuating reference signal 130b after the bias level adjustment.

On the other hand, the other signal branched from the A / D converter 52 is sent to the delay adjustment circuit 53. The delay adjustment circuit 53 performs an appropriate delay processing on the input digital signal, and outputs the output signal to the D / A converter 57a.
, Is input to the comparator 58 as the signal 130a at the same timing as the above-described reference signal 130b. The comparator 58 performs a level comparison between the input signal 130a and the reference signal 130b, and generates an accident sound detection signal 140 if the level of the input signal 130a is higher than the level of the reference signal 130b.

In FIG. 5, the output signal of the waveform shaping circuit 50 is A / D converted, rectification and moving average processing are performed, and the signal subjected to the moving average processing is D / A converted. Although the adjustment has been made, the comparator 58
Are exactly the same as those shown in FIG.
The occurrence of an accident can be detected as in the case of FIG. Thus, also in the present embodiment, the accident sound can be reliably detected without being affected by the level of the input acoustic signal.

Embodiment 5 FIG. FIG. 6 is a block diagram showing Embodiment 5 of the present invention. 6, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. In the present embodiment, the type of accident can be determined by using a plurality of accident sound detection circuits substantially as shown in FIG. In the figure, reference numeral 21 denotes an accident sound detector, 50-1, 50-2, ..., 50-i, ..., 50-n are, for example, bandpasses for waveform shaping having different frequency bands according to purposes. A band control circuit composed of a filter (BPF) or a high-pass filter (HPF);
, 59-1i,..., 59-n are accident sound detection circuits substantially corresponding to the accident sound detection circuit 11A of FIG. Instead of the circuit 50, the above-mentioned band control circuits 50-1, 50-2, 50-2,
, 50-i, ..., 50-n are used, and the other components are the same as those of the accident sound detection circuit 11A.

Reference numeral 60 denotes an accident sound detection circuit 59-1, 59-
, 59-1i,..., 59-n are logical operation circuits as accident sound discriminating means provided on the output side. The logical operation circuit 60 is an accident sound detection circuit 59-1. , 59-
, 59-1i,..., 59-n, the accident sound detection signals 140-1, 140-2,.
.., 140-n to generate a final accident sound detection signal in which the type of accident is also determined.

Next, the operation will be described. The acoustic signal 100 from the ambient sound detector is branched into a plurality of channels, and the accident sound detector circuits 59-1, 59-2,.
, 59-n. In each of the accident sound detection circuits, the band limiting circuits 50-1, 50-2,..., 50-i,.
−n is provided, so that the input acoustic signal 100
Is limited to signal components in a frequency band according to the purpose, and when the same signal processing is performed as described above and an accident sound exists in the frequency band, the corresponding accident sound detection circuits 59-1 and 59-
, 59-i, ..., 59-n, respectively, the accident sound detection signals 140-1, 140-2, ..., 140-i, ...
.., 140-n are generated.

Normally, these accident sound detection signals may or may not be generated according to the frequency spectrum of the accident sound. For example, in the case of a sudden braking sound that may lead to an accident, the frequency spectrum is often concentrated at 1 kHz or 2 kHz, and an accident sound detection signal having a band limiting circuit including these frequency bands generates an accident sound detection signal. However, the accident sound detection circuit of the band limiting circuit whose frequency is limited to, for example, 5 kHz to 10 kHz does not generate an accident sound detection signal. These accident sound detection signals are then input to the logic operation circuit 60. The logical operation circuit 60 performs a logical operation process based on each of the accident sound detection signals, and generates a desired final accident sound detection signal that has passed a predetermined frequency band, that is, the type of accident has also been determined. .

Further, the operation of the present embodiment will be described with reference to FIG. 7 on the logic of generating an accident sound detection signal when an accident sound such as a collision sound or a sudden braking sound is input. Here, the frequency spectrum of the collision sound varies depending on the state of the collision. Generally, the frequency spectrum is often around 8 kHz, and in the case of a sudden braking sound that may lead to an accident, the frequency spectrum is concentrated at 1 kHz or 2 kHz as described above. In consideration of the fact that the frequency band is often high, in FIG. 7, as an example, each of the frequency bands is 8 kHz or more, 1 kHz to 2 kHz,
Band limiting circuits 50-1 and 50 for changing the frequency from 6 kHz to 10 kHz
-2, 50-3, respectively.
59-2, 59-3, and a NOT circuit 61, which inverts the accident sound detection signal 140-3 from the accident sound detection circuit 59-3,
The accident sound detection signal 140 inverted by the NOT circuit 61
-3 and the accident sound detection signal 1 from the accident sound detection circuit 59-2
An AND circuit 62 which takes a logical product of the AND circuit 40-2 and the AND circuit
OR circuit 63 for performing a logical sum of the output signal of D circuit 62 and the accident sound detection signal 140-1 from the accident sound detection circuit 59-1
Sound detection device 2 having a logical operation circuit 60 composed of
1 is shown.

Now, the acoustic signal 10 from the ambient sound detecting device
When 0 is input to the accident sound detection circuits 59-1, 59-2, 59-13, each of the accident sound detection circuits has a band limiting circuit 50-.
Each of the frequency bands is set to 8 by 1, 50-2, and 50-3.
Since the frequency is limited to 1 kHz to 2 kHz and 6 kHz to 10 kHz, focusing on the collision sound and the sudden braking sound, the collision sound has a band limiting circuit 50-11 of 8 kHz or more. Accident sound detection circuit 59-
An accident sound detection signal is generated from an accident sound detection circuit 59-3 having a band limiting circuit 50-3 of 1 to 6 kHz to 10 kHz. However, the accident sound detection signal from the accident sound detection circuit 59-3 is negated by the NOT circuit 61, and the accident sound detection signal is not substantially passed. That is, the output signal of the NOT circuit 61 is, for example, low level “0”.

Accordingly, at this time, the accident sound detection circuit 59-2
Regardless of the level of the accident sound detection signal 140-2 from
Since the output signal of the AND circuit 62 is always at the low level "0", the gate of the AND circuit 62 is not opened, and the accident sound detection signal 140-1 of at least 8 kHz from the accident sound detection circuit 59-1 turns the OR circuit 63 on. As a result, the type of accident is discriminated, that is, it is output to the outside as a final accident sound detection signal 150 indicating a collision sound.

On the other hand, as for the sudden braking sound, since the frequency spectrum is concentrated from 1 kHz to 2 kHz, the accident sound detection signal 140-2 is generated from the accident sound detection circuit 59-2 having the band limiting circuit 50-2. From 6 kHz to 10
An accident sound detection circuit 5 having a band-limiting circuit 50-13 of kHz.
An accident sound detection signal 140 from an accident sound detection circuit 59-1 having a band limiting circuit 50-1 of 9-3 or 8 kHz or more.
-3 and 140-1 do not occur. However, the NOT signal 61 performs a negative operation on the output signal 140-3 from the accident sound detection circuit 59-3, that is, the NOT circuit 6
1 becomes a high level "1", and the logical product of the accident sound detection signal 140-2 from the accident sound detection circuit 59-2 passing through the band limiting circuit 50-2 and the output signal of the NOT circuit 61. Is calculated by the AND circuit 62, the output signal is at high level "1", that is, the gate of the AND circuit 62 is opened and the accident sound detection circuit 59-2 detects the accident sound from the accident sound detection circuit 59-2. The signal 140-2 is the OR circuit 6
3, the signal is output to the outside as a final accident sound detection signal 150 indicating that the type of accident has been determined, that is, a brake sound.

As described above, also in the present embodiment, the accident sound can be reliably detected without being affected by the level of the input acoustic signal, and furthermore, in the present embodiment, the detected accident sound can be detected. The type can also be determined. The setting of the frequency band of the band limiting circuit described above is an example, and may be set arbitrarily according to the frequency spectrum of the accident sound. It can be set arbitrarily without limitation, and in this case, the number of logic circuits of the logic operation circuit 60 is naturally changed accordingly. Further, in the present embodiment, the case where the remaining circuit portion of the accident sound detection circuit 11A except for the waveform shaping circuit 50 of FIG. 1 is used as the circuit configuration of the accident sound detection circuit has been described. The accident sound detection circuits 11B to 11B of FIGS.
The remaining circuit portion other than the waveform shaping circuit 50 of D may be used, and the same effect is obtained.

Embodiment 6 FIG. FIG. 8 is a block diagram showing Embodiment 6 of the present invention. 8, parts corresponding to those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted. In the present embodiment, discrimination of the type of accident is performed by comparing a pattern of an input signal with a preset pattern. In the figure, 21A is an accident sound detection device, 64 is an accident sound detection circuit 59-1, 59-2,.
, 59-1i,..., 59-n are provided on the output side, and the pattern comparison circuit 64 is provided with an accident sound detection circuit 59-1, 59-2,. One i, ...
, An accident sound detection signal 1 generated from each of 59-n
40-1, 140-2, ..., 140-i, ..., 140
A pattern representing -n is compared with a preset pattern from the pattern signal generator 65, and when they match, a final accident sound detection signal is generated in which the type of accident is also determined. This setting pattern is set, for example, by analyzing a collision sound or a sudden braking sound, and standardizing it.
The pattern comparing circuit 64 and the pattern signal generator 65 constitute an accident sound discriminating means.

Next, the operation will be described. The acoustic signal 100 from the ambient sound detector is branched into a plurality of channels, and the accident sound detector circuits 59-1, 59-2,.
, 59-n. In each of the accident sound detection circuits, the band limiting circuits 50-1, 50-2,..., 50-i,.
−n is provided, so that the input acoustic signal 100
Is limited to signal components in a frequency band according to the purpose, and when the same signal processing is performed as described above and an accident sound exists in the frequency band, the corresponding accident sound detection circuits 59-1 and 59-
, 59-i, ..., 59-n, respectively, the accident sound detection signals 140-1, 140-2, ..., 140-i, ...
.., 140-n are generated.

As described above, these accident sound detection signals are:
There are cases where the frequency spectrum is generated according to the frequency spectrum of the accident sound and cases where the frequency spectrum is not generated. For example, in the case of a sudden braking sound that may lead to an accident, the frequency spectrum is often concentrated at 1 kHz or 2 kHz. An accident sound detection signal is generated by an accident sound detection circuit having a band limiting circuit including a band, but an accident sound detection signal is not generated by an accident sound detection circuit of a band limiting circuit whose frequency is limited to, for example, 5 kHz to 10 kHz. These accident sound detection signals are then input to the pattern comparison circuit 64. The comparison circuit 64 forms patterns representing the accident sound detection signals based on the accident sound detection signals. That is, for example, when the accident sound detection signal is “present”, the logic level is “1”, and when the accident sound detection signal is “absent”, the logic level is “1”. A pattern to be set to "0" is formed, and the pattern is compared with a preset pattern from the pattern signal generator 65 having a bit number corresponding to the bit number of this pattern. In other words, a final accident sound detection signal is generated, which is the target in which the type of accident is also determined.

The operation of the pattern comparison circuit 64 will be further described with reference to FIG. In FIG. 9, setting patterns in the pattern signal generator 65 are BPF1, BPF2,... Corresponding to the band limiting circuits 50-1, 50-2,..., 50-i,. ..., BPF
Assuming that “11011101” (in the case of an eight-channel band limiting circuit as an example) in the order of i,..., BPFn,
Accident sound detection circuits 59-1, 59-2, ..., 59-i, ...
From the accident sound detection signals 140-1,
The pattern of 140-2, ..., 140-i, ..., 140-n is, for example, "01101011" (output pattern 1).
When input to the pattern comparison circuit 64, the patterns do not match, so that the pattern comparison circuit 64 does not generate the final accident sound detection signal 150.

However, the accident sound detection circuits 59-1 and 59-
, 59-i, ..., 59-n, respectively, the accident sound detection signals 140-1, 140-2, ..., 140-i, ...
.., the pattern of 140-n is, for example, "1101110
If the pattern is input as 1 "(output pattern 2) to the pattern comparison circuit 64, the patterns match, so the pattern comparison circuit 64 has determined the type of the accident, that is, the final accident indicating, for example, a brake sound. Sound detection signal 15
0 is output to the outside.

As described above, also in the present embodiment, the accident sound can be reliably detected without being affected by the level of the input acoustic signal, and in the present embodiment, the detected accident sound can be detected. The type can also be determined. The setting of the frequency band of the band limiting circuit described above is an example, and may be set arbitrarily according to the frequency spectrum of the accident sound. The setting pattern can be set arbitrarily without limitation. Therefore, the setting pattern can be set arbitrarily in accordance with the output pattern. Also, in the present embodiment, the case where the remaining circuit portion except the waveform shaping circuit 50 of the accident sound detection circuit 11A of FIG. 1 is used as the circuit configuration of the accident sound detection circuit has been described. The waveform shaping circuit 50 of each of the accident sound detection circuits 11B to 11D shown in FIGS.
May be used, and the same effect can be obtained.

[0050]

As described above, the accident sound detection circuit according to the present invention uses an acoustic signal from an ambient sound detection device disposed near an intersection or a road to detect an accident sound. A detection circuit, a waveform shaping circuit for shaping the waveform of an acoustic signal from an ambient sound detection device, and a reference signal for performing moving average processing and bias level adjustment on one of the branched signals from the waveform shaping circuit Generating means; delay adjusting means for delaying the other signal output from the reference signal generating means by delaying the other signal branched from the waveform shaping circuit; and adjusting the output and delay of the reference signal generating means. Means for comparing with the output of the means and generating an accident sound detection signal in accordance with the result of the comparison, so that the accident sound can be reliably detected without being affected by the level of the input acoustic signal. There is an effect that.

Further, the accident sound detection device according to the present invention comprises:
A plurality of accident sound detection circuits that are connected in parallel to the input acoustic signal and are each limited to a different frequency band, and determine the accident sound from the accident sound detection signals from the plurality of accident sound detection circuits. With the accident sound discriminating means that generates the final accident sound detection signal, the accident sound can be reliably detected without being affected by the level of the input sound signal, and the accident type information is included. There is an effect that the accident sound can be determined.

[Brief description of the drawings]

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

FIG. 2 is a signal waveform diagram for describing the operation of FIG.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing Embodiment 3 of the present invention.

FIG. 5 is a block diagram showing a fourth embodiment of the present invention.

FIG. 6 is a block diagram showing a fifth embodiment of the present invention.

FIG. 7 is a configuration diagram for explaining the operation of FIG. 6;

FIG. 8 is a block diagram showing a sixth embodiment of the present invention.

FIG. 9 is a diagram provided for explanation of the operation in FIG. 8;

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

[Explanation of symbols]

11A-11D accident sound detection circuit, 21, 21A accident sound detection device, 50 waveform shaping circuit, 50-1, 50-
2, ..., 50-i, ..., 50-n band limiting circuit, 5
2, 52a, 52b A / D converter, 53 delay adjustment circuit, 54 moving average circuit, 55 adder, 56 bias signal generator, 57a, 57b D / A converter, 58
.., 59-i,..., 5
9-n accident sound detection circuit, 60 logic operation circuit, 64
Pattern comparison circuit, 65 pattern signal generator.

Continuation of the front page (56) References JP-A-3-113599 (JP, A) JP-A-56-41399 (JP, U) JP-A-64-54199 (JP, U) JP-A-57-166296 (JP) , U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) G08G 1/00-1/16

Claims (9)

(57) [Claims] 1. An accident sound detection circuit for detecting an accident sound using an acoustic signal from an ambient sound detection device disposed near an intersection or a road, the waveform of the acoustic signal from the ambient sound detection device. A waveform shaping circuit for shaping the signal; reference signal generating means for performing moving average processing and bias level adjustment on one of the signals branched from the waveform shaping circuit; and the other signal branched from the waveform shaping circuit. A delay adjusting means for performing a delay correction between the output from the reference signal generating means by delaying the output, and comparing the output of the reference signal generating means with the output of the delay adjusting means. And a comparing means for generating an accident sound detection signal in response to the accident sound detection circuit. 2. The apparatus according to claim 1, wherein said comparing means generates an accident sound detection signal when a signal from said delay adjusting means is larger than a signal from said reference signal generating means.
The accident sound detection circuit described. 3. A first A / D converter for A / D converting an output of the waveform shaping circuit, wherein the reference signal generating means includes:
A moving average circuit for calculating a moving average of the output of the / D converter, a bias signal generator for generating a bias signal, and an adder for adding the output of the moving average circuit and the output of the bias signal generator The delay adjusting means includes a second A / D converter for A / D converting the output of the waveform shaping circuit, and a delay adjusting circuit for delaying the output of the A / D converter;
The comparing means includes a first D / A converter for D / A converting the output of the delay adjustment circuit, a second D / A converter for D / A converting the output of the adder, and the first D / A converter. And the second D
3. The accident sound detection circuit according to claim 1, further comprising a comparator for comparing the output of the / A converter. 4. The accident sound detection circuit according to claim 3, wherein said first and second A / D converters are shared. 5. The accident sound detection circuit according to claim 3, wherein said first D / A converter is provided at a stage preceding said adder. 6. The plurality of accident sound detection circuits according to claim 1, wherein the plurality of accident sound detection circuits are connected in parallel to an input acoustic signal, and are each limited to a different frequency band. An accident sound detecting device, comprising: an accident sound discriminating means for judging an accident sound from an accident sound detection signal from a sound detection circuit to generate a final accident sound detection signal. 7. The accident sound detection apparatus according to claim 6, wherein said accident sound discrimination means is a logical operation circuit for judging an accident sound by processing an accident sound detection signal from said plurality of accident sound detection circuits. 8. The accident sound judging means is a pattern comparing means for judging an accident sound by comparing a pattern of an accident sound detection signal from the plurality of accident sound detecting circuits with a predetermined pattern. The accident sound detection device as described. 9. The accident sound detector according to claim 8, wherein said pattern comparing means comprises a pattern comparing circuit and a pattern signal generator for generating a predetermined pattern.