JP2015022453A - Emergency vehicle alarm system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide emergency vehicle information without any error detection by combining a camera and a microphone.SOLUTION: Surrounding sound and video are acquired by an omnidirectional camera 5 and four pieces of microphones 3 (3a to 3d) respectively arranged on a roof of a vehicle. The position (direction) of the siren is detected by processing the output signals with a voice signal processing part 10a of a signal processing unit 10, and the position of a reflective body capable of reflecting sound is detected by processing with an image signal processing part 10b. In a control unit 11, the position of the siren is deemed to be the position of the emergency vehicle when no reflective body exists in the direction of the siren. When the reflective body exists, it is determined that the position of the siren is reflected noise due to the body, and a search is performed for a sound signal with low sound pressure level and in a direction where the reflective body does not exist, the direction is deemed to be the position of the emergency vehicle. When the emergency vehicle is moving in the same direction as own vehicle, approaching alarm is displayed to a speaker 15 and a monitor 16.

Description

  The present invention relates to an emergency vehicle notification system that is mounted on a vehicle and detects an approaching state of an emergency vehicle such as a police vehicle, a fire engine, or an ambulance vehicle, and provides the information to an occupant.

If an emergency vehicle approaches while driving, you must evacuate to the side of the road to secure a runway for the emergency vehicle, but for example, when driving with the window closed, the siren is difficult to hear, There are many cases where it is not possible to recognize the approach of an emergency vehicle, such as when the rear view through the rearview mirror is behind the following vehicle and the red light is not visible.
For this reason, conventionally, a technology has been proposed in which information is provided by automatic detection without relying only on the driver's attention, and the occupant is surely aware of the approaching state of the emergency vehicle.
For example, Japanese Patent Application Laid-Open No. 11-306494 describes a technology in which a microphone and a camera are mounted on a vehicle, an emergency vehicle coming from behind is detected, and a vehicle occupant is notified by a display device such as a video monitor or text / voice. ing.

Specifically, the camera is installed at the upper part of the rear window facing backward, and the microphone is installed at the same position as the camera.
In addition, a camera and microphone unit is installed on the side of the vehicle body for detecting an emergency vehicle from the left and right, and at the front end of the vehicle body for detecting a dangerous zone and a crossing in front.
This makes it possible to know the presence of an emergency vehicle 100% reliably when capturing a red light image with a camera and a siren sound with a microphone. Even if it is impossible to detect a fogging image, it is said that the sound can be detected by the microphone, so that the function is not impaired even on a rough road.

JP-A-11-306494

By the way, it is obvious if you have driving experience, but even if the emergency vehicle is in front, the driver correctly recognizes the direction of the emergency vehicle with his / her ears even when surrounded by miscellaneous sounds. It is difficult to do this, and in order to detect this with the system, it is necessary to analyze the sound from all directions.
However, in the above conventional example, the microphones directed forward and laterally are at a low position, as is apparent from the illustration of the publication, and therefore various noises such as engine noise and road noise of surrounding vehicles are detected in emergency vehicle detection. Therefore, the recognition accuracy is extremely low, and there is a possibility that the function cannot actually be performed.

  In addition, the rear camera installed at the top of the rear window is a detection means that can pinpoint the exact position by capturing the red light of the emergency vehicle. In such a case, the driver can easily see through the rearview mirror. It is a state that can be done. Rather, in many cases, the road is curved and the view is poor, or it is in the shadow of a building, and often cannot be captured by the camera. In addition, it is almost impossible to obtain an emergency vehicle image with a front camera and a side camera installed at a low position because the trains and parallel cars are also obstructed. Therefore, even though four cameras are mounted at high cost, the function is not effectively used.

  And as a serious problem, when there are large buildings and walls along the road, or when trucks with large wall cargo compartments are running side by side, these become reflective objects of sound, Since the reflected sound enters the microphone from a direction different from that of the emergency vehicle, an event may occur in which the position (direction) of the emergency vehicle is erroneously detected when a determination is made based only on the output of the microphone without capturing the red light with the camera. However, no preventive measures against this are shown.

  Therefore, in view of the above-described problems, an object of the present invention is to provide an emergency vehicle notification system that is free from erroneous detection by using an effective combination of a camera and a microphone at low cost.

For this reason, the emergency vehicle notification system of the present invention is provided with a plurality of microphones that collect sound by sharing sound around the vehicle with directivity and an omnidirectional camera that captures images around the vehicle, respectively. ,
Siren detection means for recognizing the siren by processing the microphone output as an audio signal and detecting the position of the sound source;
Image processing means for recognizing a reflective object capable of reflecting sound by performing image signal processing on the output of the omnidirectional camera, and detecting its position;
Control means for determining the position of the emergency vehicle based on the detection result of the siren detection means and the image processing means, and displaying the emergency vehicle information including the position on the display means;
When there is no reflecting object in the direction of the sound source, the control means sets the position of the sound source as the position of the emergency vehicle, and when there is a reflecting object in the direction of the sound source, the corrected new position is set as the position of the emergency vehicle. To do.

A microphone and omnidirectional camera that covers the omnidirectional area around the vehicle are installed at the top of the vehicle body, which frees you from engine noise and road noise, and significantly reduces the influence of other nearby vehicles. In addition, the sirens of emergency vehicles located in any direction can be detected very easily, and sound reflecting objects such as buildings along the road can be accurately and reliably grasped.
And it can be confirmed that the siren sound recognized by the siren detection means is not a reflected sound, and if it is a reflected sound, it is corrected. improves.
The acquisition of the video around the vehicle is low because it requires only one omnidirectional camera.

It is a block diagram which shows the structure of embodiment of this invention. It is a figure which shows a sensor unit. It is a flowchart which shows the flow of the process in an emergency vehicle alert system. It is a flowchart which shows the flow of the process in an emergency vehicle alert system.

Embodiments of the present invention will be described below.
FIG. 1 is a block diagram illustrating a configuration of an emergency vehicle notification system according to an embodiment.
The emergency vehicle notification system 1 has four microphones 3 (3a, 3b, 3c, 3d) and one omnidirectional camera 5, and detects the approaching state of the emergency vehicle based on these outputs. Is provided as emergency vehicle information.
The microphone 3 and the omnidirectional camera 5 are installed on the roof top surface of the vehicle M as one sensor unit 2 as shown in FIG.

2A is a side view showing a state in which the sensor unit 2 is installed in the vehicle M, FIG. 2B is a perspective view of the sensor unit 2, and FIG. 2C is a cross-sectional view through the microphone 3 in the sensor unit 2. is there.
The microphone 3 shares the front-rear and left-right directions of the vehicle, and each has a horn 4 to output an audio signal with high directivity and high gain.
The omnidirectional camera 5 is located above the center of the group of microphones 3, and has a configuration in which, for example, a mirror is provided to guide light from a surrounding 360 ° to the light receiving element mechanically, and one unit outputs an omnidirectional video signal.

Returning to FIG. 1, each microphone 3 is connected to a signal processing unit 10 via a band amplifier 7 (7a, 7b, 7c, 7d) and an A / D converter 8, and the omnidirectional camera 5 is also connected to the A / D. It is connected to the signal processing unit 10 via the converter 9.
The signal processing unit 10 is connected to a control unit 11 composed of a CPU. A vehicle speed sensor 12 and an input operation unit 13 for setting various conditions are further connected to the input side of the control unit 11.
A speaker 15 and a monitor 16 are connected to the output side of the control unit 11 via an amplifier 14.
The control unit 11 controls the entire emergency vehicle detection system 1, determines the approaching state of the emergency vehicle based on the processing result from the signal processing unit 10 and the vehicle speed signal from the vehicle speed sensor 12, and sends the information from the speaker 15. It announces by voice, and draws and displays on the monitor 16 with characters and graphics.
Note that the interfaces necessary for power supply and signal exchange in each connection system are not shown.

The band amplifier 7 includes a band filter (not shown), cuts other bands while leaving a predetermined frequency band whose center frequency is the siren frequency of the emergency vehicle, and amplifies the output of the microphone 3 to a level within a predetermined range. And output to the signal processing unit 10. The predetermined frequency band is set in consideration of frequency fluctuations that change due to Doppler shift.
The omnidirectional camera 5 outputs a video signal around the host vehicle to the signal processing unit 10.

The signal processing unit 10 includes an audio signal processing unit 10a and an image signal processing unit 10b.
In the audio signal processing unit 10a, the noise around the vehicle is canceled with respect to the output of the microphone 3 by the audio signal processing, and the siren of the emergency vehicle is extracted in comparison with a predetermined sound range pattern. Then, the position (direction) of the extracted siren sound source is calculated. The position of the sound source can be obtained by vector calculation from two outputs of the microphone 3 having a high sound pressure level since each microphone has directivity.
In the present application, the position of the sound source means the direction viewed from the own vehicle, and therefore the position of the emergency vehicle and the position of the red light described later also refer to the direction viewed from the own vehicle. Hereinafter, (position) is appropriately given to “position”, but the same meaning is given when it is not attached.

  Further, the audio signal processing unit 10a calculates the position (direction) by searching for a sub-sound signal having the same pattern and a low sound pressure level by using the extracted siren as a main sound signal according to a command from the control unit 11. To do. Both the main sound signal and the secondary sound signal may be detected when reflected by a reflecting object such as a building.

The image signal processing unit 10b performs image signal processing on the video signal from the omnidirectional camera 5, extracts a red light of an emergency vehicle, calculates its position (direction), and reflects an object that reflects sound (the building described above) And the presence or absence and position thereof.
The control unit 11 determines the position of the emergency vehicle based on the processing result from the signal processing unit 10 and the vehicle speed signal, and provides emergency vehicle information including the approaching state to the occupant through the display of the speaker 15 and the monitor 16. .

3 and 4 are flowcharts showing the flow of processing in the emergency vehicle notification system 1, particularly the control unit 11.
The emergency vehicle notification system 1 is turned on together with the operation of an ignition switch (not shown) of the vehicle, and the signal processing unit 10 starts the audio signal processing of the signal from the microphone 3 and the image signal processing of the video from the omnidirectional camera 5.
The controller 11 first initializes the display of the monitor 16 on the emergency vehicle in step 100, and then in step 101, the audio signal processing result for the audio signal from the microphone 3 and the image signal processing for the video signal from the omnidirectional camera 5. The result is read from the signal processing unit 10.
In step 102, it is checked whether a siren is included in the audio signal processing result, that is, whether the position (direction) of the sound source of the siren is detected.
When the siren is detected, the process proceeds to step 103, and when it is not detected, the process proceeds to step 116.

In step 103, it is checked whether the image signal processing result includes a red light, that is, whether the position (direction) of the red light is detected.
When a red light is detected, the routine proceeds to step 104, and when it is not detected, the routine proceeds to step 107.
In step 104, it is checked whether the detected siren sound source and the position (direction) of the red lamp are the same.
When the position (direction) of the siren and the red light is the same, the control unit 11 determines in step 105 that the emergency vehicle is in the direction of the sound source (and red light) of the siren, and proceeds to step 112.
When the position (direction) of the siren and the red light is not the same, the siren is a reflected sound. Therefore, in step 106, it is determined that the emergency vehicle is in the direction of the red light, and the process proceeds to step 112.

If the red light is not detected in the check in step 103, it is checked in step 107 whether the image signal processing result includes a sound reflecting object such as a building.
If there is no sound reflecting object in the siren direction, it is determined in step 108 that the emergency vehicle is in the siren direction, and the process proceeds to step 112.

If there is a sound reflecting object in the direction of the detected siren (main sound signal), the routine proceeds to step 109. In this case, assuming that the siren is a reflected sound from the reflecting object and does not indicate the correct position (direction), the control unit 11 uses the same pattern as the main sound signal for the signal processing unit 10 and the sound pressure level is the same. A search for a sub-tone signal that is lower than the sound pressure level of the main tone signal is commanded. This is because there is a difference in sound pressure level between the sound that reaches directly and the sound that reflects and arrives through different paths.
In step 109, it is checked whether or not a secondary sound signal has been detected.
If no secondary sound signal is detected, the process returns to step 101.

When the secondary sound signal is detected, the routine proceeds to step 110, where it is checked whether or not there is a sound reflecting object in the direction of the secondary sound signal.
If there is no sound reflecting object in the direction of the secondary sound signal, it is determined in step 111 that the emergency vehicle is in the direction of the secondary sound signal, and the process proceeds to step 112.
If there is a sound reflecting object also in the direction of the secondary sound signal, there is a high possibility that this is also a reflected sound from the reflecting object, and it returns to step 101 assuming that the correct position (direction) is not indicated. .

In step 112, the control unit 11 reads the vehicle speed of the host vehicle, and in subsequent step 113, the control unit 11 checks whether the emergency vehicle in which the siren is detected is moving in the same direction as the host vehicle.
Here, the relative speed of the host vehicle and the emergency vehicle is obtained based on the Doppler shift. However, when the relative speed in the separation direction is smaller than the vehicle speed of the host vehicle, the emergency vehicle has the same traveling direction as the host vehicle and is in the same direction. You will be traveling.
When the emergency vehicle is moving in the same direction as the host vehicle, even if the host vehicle is relatively fast, it should be evacuated at a reduced speed, so whether the emergency vehicle is faster or slower than the host vehicle speed. Regardless of whether or not the vehicle is traveling in the same direction as the host vehicle.
Even when the position of the emergency vehicle is set to the direction of the red light in step 106, the moving direction can be obtained based on the reflected sound.

When the traveling direction of the emergency vehicle is the same as that of the host vehicle, the process proceeds to step 114, and the speaker 15 and the monitor 16 are driven to output an emergency vehicle approach warning. For example, the speaker 15 outputs a voice message “Emergency vehicle is approaching from behind. Please bring the car to the side.”, And the monitor 16 displays a text display with the same meaning and the direction of the emergency vehicle viewed from the own vehicle. Display.
On the other hand, when the traveling direction of the emergency vehicle is different from that of the own vehicle, the routine proceeds to step 115, for example, “the emergency vehicle is moving in another direction” for passengers who are wondering whether to deal with the siren. The evacuation unnecessary information is displayed on the speaker 15 and the monitor 16.

When the siren is not detected in the previous step 102, the process proceeds to step 116 to check whether the position (direction) of the red light is detected.
When the red light is not detected, the emergency vehicle is not detected, and the process returns to step 101.
When the red light is detected, the process proceeds to step 117, and emergency vehicle appearance information such as “There is an emergency vehicle behind. Please pay attention to the trend” is displayed on the speaker 15 and the monitor 16.

Although not shown in particular, when displaying emergency vehicle information, that is, an emergency vehicle approach warning in step 114, evacuation unnecessary information in step 115, and emergency vehicle appearance information in step 117, the information is canceled on the screen of the monitor 16 together with the information. A button is displayed so that the occupant can operate by touching his / her finger appropriately after the information is recognized.
In step 118, it is checked whether or not the cancel button has been operated.
While the cancel button is not operated, the process returns to step 101 and the above flow is repeated, and the display of the speaker and the monitor is updated.

When the cancel button is operated, the control unit 11 turns off the display of the speaker 15 and the monitor 16 for a predetermined time in step 119. Then, after the predetermined time has elapsed, the process returns to step 101 again.
This predetermined time is set to a few minutes that normally elapse from the emergence of an emergency vehicle until the vehicle passes and the siren is no longer heard, thereby avoiding the unnecessary repetition of information related to the emergency vehicle after passing. Is done.
The specific message of the emergency vehicle information displayed on the predetermined time and the speaker 15 and the monitor 16 can be set and changed from the input operation unit 13.

With the above control, when the siren is detected mainly based on the audio signal from the microphone 3 and the emergency vehicle is notified, the siren can be confirmed by the video signal of the omnidirectional camera 5 and the siren is not reflected sound from the reflecting object. In the case of reflected sound, the position (direction) of the emergency vehicle is corrected, so that high reliability can be obtained.
Although only one omnidirectional camera 5 is required and it is configured at low cost, when the siren cannot be detected by the microphone 3, the emergence of the emergency vehicle is notified based on the video signal, so that reliable backup is realized.

In the present embodiment, the audio signal processing unit 10a corresponds to the siren detection means in the invention, and the image signal processing unit 10b corresponds to the image processing means. The speaker 15 and the monitor 16 constitute display means.
3 and 4 in the control unit 11 constitutes a control means in the invention, and the direction of the secondary sound signal corresponds to the direction of the second sound source. .

The embodiment is configured as described above, and four microphones 3 (3a to 3d) that are directed in the front-rear and left-right directions of the vehicle M to share sound around the vehicle with directivity and collect sound, An omnidirectional camera 5 that captures images of the surroundings of the vehicle is installed on the top surface of the roof. The audio signal processing unit 10a of the signal processing unit 10 performs audio signal processing on the output of the microphone 3 to recognize sirens and determines the position of the sound source. Then, the image signal processing unit 10b detects the reflection object capable of reflecting sound by image signal processing the output of the omnidirectional camera 5 and detects the position thereof, and the control unit 11 and the audio signal processing unit 10a perform image signal processing. An emergency vehicle notification system that determines the position of an emergency vehicle based on the detection result of the unit 10b and displays emergency vehicle information including the position on the speaker 15 and the monitor 16, and includes a sound source of a siren The position of the emergency vehicle to the position of the sound source when there is no reflecting object in the direction, when the reflective object in the direction of the sound source is present is assumed to correct the position of the emergency vehicle.
As a result, first, the four microphones 3 and the omnidirectional camera 5 covering the omnidirectional area around the vehicle are installed at the top of the vehicle body, so that they are free from engine noise and road noise, and are shaded. The influence of other vehicles in the vicinity is also greatly reduced, and sirens of emergency vehicles located in all directions can be detected very easily, and sound reflecting objects such as buildings along the road can be grasped accurately and reliably.
And it can confirm that the sound of the siren recognized by the audio signal processing unit 10a is not a reflected sound, and if it is a reflected sound, it is corrected. Improves.
Since the image acquisition around the vehicle can be performed by one omnidirectional camera 5, it can be realized at low cost.

  Regarding the correction of the position of the emergency vehicle, a search is made for a secondary sound signal having the same pattern as the sound recognized as a siren by the voice signal processing unit 10a and having a lower sound pressure level, and the processing result of the image signal processing unit 10b. When there is no reflecting object in the direction of the secondary sound signal, the position of the secondary sound signal is set as a new position of the emergency vehicle, so the emergency vehicle information at the correct position based on the secondary sound signal emitted from the same emergency vehicle. Can be provided.

Since the image signal processing unit 10b further recognizes the red light and detects its position, the position of the sound source detected by the audio signal processing unit 10a can be confirmed by comparing with the position of the red light. If the position of the sound source is different from the position of the red light, it is clear that the sound is a reflected sound. Therefore, verification of the presence or absence of a reflecting object can be omitted, and the position of the red light can be set as the position of the emergency vehicle.
Since each of the microphones 3 includes the horn 4, high directivity and a large gain can be obtained.
Since the microphone 3 and the omnidirectional camera 5 are integrated as one sensor unit 2, it can be easily installed on the vehicle body.

In the embodiment, when the voice signal processing unit 10a receives a command from the control unit 11, the voice signal processing unit 10a searches for a secondary sound signal having a sound pressure level lower than that of the main sound signal of the siren, but waits for the command. Instead, the secondary sound signal may be searched and the result may be output to the control unit 11 together with the main sound signal.
In this case, when it is determined in step 106 that the emergency vehicle is in the direction of the red light, it can be confirmed that the secondary sound signal is in the same direction as the red light.
In addition to searching for the sub-tone signal based on the difference in sound pressure level, for example, a signal having a phase shift in the same pattern as the main sound signal may be searched.

  The image signal processing unit 10b calculates only the position (direction) for detection of the red light. However, depending on the resolution of the omnidirectional camera 5, whether the approach or departure is caused by the change in the area of the red light in the image frame. The moving direction can also be detected, and the process of steps 112 and 113 in FIG. 4 can be performed in the same manner as the siren, and an emergency vehicle approach warning including the moving direction can be provided even in the display at step 117, for example.

  When the secondary sound signal is not detected in step 109 of FIG. 3 and when there is a sound reflecting object in the direction of the secondary sound signal in step 110, the process returns to step 101. Emergency vehicle appearance information such as “Emergency vehicle siren detected. Please pay attention to trends” may be displayed on the speaker 15 or the monitor 16.

  In step 113 of FIG. 4, it is determined whether the emergency vehicle is traveling in the same direction as the own vehicle regardless of whether the emergency vehicle is faster or slower than the vehicle speed of the own vehicle, and the emergency vehicle is moving in the same direction. In such a case, an emergency vehicle approach warning is displayed in step 114. However, when the relative speed with respect to the emergency vehicle is equal to or higher than a predetermined value, it is possible to display information that does not need to be saved because it is certain that the vehicle will be separated. The reference relative speed can be set by operating the input operation unit 13.

DESCRIPTION OF SYMBOLS 1 Emergency vehicle detection system 2 Sensor unit 3, 3a, 3b, 3c, 3d Microphone 4 Horn 5 Omnidirectional camera 7a, 7b, 7c, 7d Band amplifier 8, 9 A / D converter 10 Signal processing part 11 Control part 12 Vehicle speed Sensor 13 Input operation unit 14 Amplifier 15 Speaker 16 Monitor M Vehicle

Claims (8)

A plurality of microphones that collect sound by sharing sound around the vehicle with directivity and an omnidirectional camera that captures images around the vehicle are installed at the top of the vehicle body.
Siren detection means for recognizing the siren by processing the output of the microphone as an audio signal and detecting the position of the sound source;
Image processing means for recognizing a reflective object capable of reflecting sound by performing image signal processing on the output of the omnidirectional camera and detecting its position;
Control means for determining the position of the emergency vehicle based on the detection result of the siren detection means and the image processing means, and displaying the emergency vehicle information including the position on the display means,
When there is no reflecting object in the direction of the sound source, the control means sets the position of the sound source as the position of the emergency vehicle, and when there is a reflecting object in the direction of the sound source, the corrected new position is the position of the emergency vehicle. An emergency vehicle notification system characterized by that. The siren detection means searches for a second sound source whose sound pressure level is lower than that of the siren;
2. The emergency vehicle notification system according to claim 1, wherein the control unit sets the position of the second sound source as the corrected new position when there is no reflecting object in the direction of the second sound source. . The image processing means further recognizes the red light and detects its position;
When the position of the sound source detected by the siren detection means is different from the position of the red light detected by the image processing means, the control means uses the position of the red light as the position of the emergency vehicle. The emergency vehicle notification system according to claim 1 or 2.   The emergency microphone according to any one of claims 1 to 3, wherein the microphone includes four microphones oriented in the front-rear and left-right directions of the vehicle, and is disposed on a roof of the vehicle together with the omnidirectional camera. Vehicle notification system.   The emergency vehicle notification system according to claim 4, wherein each of the microphones includes a horn. An emergency vehicle position detection method in an emergency vehicle notification system that includes a microphone and an omnidirectional camera and displays emergency vehicle information including the position of an emergency vehicle on a display means based on audio and video signals from these. And
The microphone is installed in the upper part of the vehicle body, and the sound around the vehicle is divided and collected with directivity,
The omnidirectional camera is installed at the top of the car body to shoot images around the vehicle,
The microphone output is processed as an audio signal and the siren is recognized to detect the position of the sound source,
The output from the omnidirectional camera is subjected to image signal processing to recognize a reflective object capable of reflecting sound, and its position is detected.
When there is no reflecting object in the direction of the sound source, the position of the sound source is set as the position of the emergency vehicle, and when a reflecting object exists in the direction of the sound source, the new position obtained by correcting the position of the sound source is set as the position of the emergency vehicle. A method for detecting the position of an emergency vehicle. The correction of the position of the sound source is as follows:
Search for a second sound source whose sound pressure level is lower than the recognized siren,
The emergency vehicle position detection method according to claim 6, wherein the position of the second sound source is set as a new position when there is no reflecting object in the direction of the second sound source. Recognize the red light further in the image signal processing, detect its position,
The position of the red light is determined to be the position of an emergency vehicle by omitting discrimination based on the reflecting object when the position of the sound source of the siren and the position of the red light are different. Emergency vehicle position detection method.

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