Road tunnel fire detection system and road tunnel fire detection method

Abstract

To provide a road tunnel fire detection system capable of early detecting a fire by organically combining a plurality of types of photographed images such as images photographed by an infrared imaging camera and a visible light imaging camera.SOLUTION: A road tunnel fire detection system comprises: a plurality of infrared imaging cameras 110 installed at a plurality of locations in a road tunnel; a plurality of visible light imaging cameras 120 installed at the plurality of locations in the road tunnel; and combination type fire detection means 140 for combining information from both of the captured images to detect a fire. An imaging angle changing device 111 for changing an imaging angle is provided for each of the infrared imaging cameras 120, an imaging angle changing device 121 for changing an imaging angle is provided for each of the visible light imaging cameras 120, and an angle change control section 130 is provided for transmitting an angle change signal for changing the imaging angle. The combination type fire detection means 140 interlocks with fire point candidate detection means 150 and fire occurrence point candidate detection means 160, and organically combines a plurality of types of captured images to detect a fire at an early stage.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a road tunnel fire detection system and a road tunnel fire detection method that can detect the occurrence of a fire with high accuracy based on infrared images and visible light images taken inside a road tunnel. [Background technology]

[0002] In recent years, road tunnels have become longer and longer, making fire detection in road tunnels an important issue. Once a fire breaks out in a road tunnel, passing vehicles have few escape routes and there is a risk of toxic gases filling the tunnel, so the fire must be put out quickly. Therefore, early detection of fire outbreaks is essential. Fire detection systems that detect infrared rays emitted from fires are already widely used in Japan's road tunnels, and are said to have a fire detection time of 30 seconds.

[0003] To detect fires, fire detectors that detect fire outbreaks can be installed at predetermined intervals on the side walls of road tunnels, etc. If a fire is detected by the fire detectors, an alert is sent to the management center that manages the road tunnel for automobiles. Since the location of the fire detector that detected the fire within the road tunnel is known, the system makes it possible to roughly determine the location of the fire within the road tunnel.

[0004] There are many different types of fire detectors. For example, there is an infrared fire detector, which uses a light-receiving element to detect the light emitted from the flames of a fire, and if the light-receiving element detects light above a certain threshold, it detects a fire. There is also a fire detector that uses a surveillance camera (see Patent Document 1), for example. Images inside the road tunnel are captured using a surveillance camera installed in the road tunnel, and a fire is detected based on the image data.

[0005] However, with infrared fire detectors and fire detectors that use surveillance cameras, it can be difficult to detect fires early on. Some fires may become smoke fires that do not emit flames in the early stages. Conventional infrared fire detectors and fire detectors that use surveillance cameras cannot detect smoke fires because they detect the light emitted by the fire. Furthermore, if visibility inside a road tunnel is poor due to black smoke filling the tunnel, they cannot detect the fire even if it is emitting flames.

[0006] For example, there is a fire detector that uses a visible light camera. Images inside the road tunnel are captured using surveillance cameras installed in the road tunnel, and fires are detected based on the image data. If an abnormality inside the tunnel, such as an accident or fire, is captured with a visible light camera, it is expected that a fire or a precursor to a fire will be detected. Also, if an abnormality in the driving behavior of a moving vehicle, such as a vehicle slowing down, stopping, or detouring, is captured with a visible light camera, it is expected that a fire or a precursor to a fire will be detected.

[0007] Furthermore, there is also a fire detector that uses a temperature detection sensor as an effective fire detector for smoke fires where the flame is small in the early stages. A fire detector that uses a temperature detection sensor uses the temperature sensor to detect a temperature rise at the installation location, and detects a fire if the detected temperature is above a reference value. A typical temperature detection sensor is one that uses a temperature sensor cable, which is widely used in Europe. Temperature cable sensors are already widely used in Europe and have a proven track record. Temperature sensor cables can identify the location of a fire spot from the measurement data of semiconductor temperature sensors embedded at regular intervals (standard 5m or 8m) inside the cable. Conventional fire alarms are installed at 50m intervals, but temperature sensor cables are installed at 5m intervals, allowing for more precise fire control.

[0008] Fig. 15 is a diagram showing an example of the configuration of a temperature detection sensor cable 10. Fig. 15 shows an enlarged view of the portion where the temperature sensor is incorporated. In the example configuration shown in Fig. 15, the temperature detection sensor cable 10 includes a cable jacket 11, an aluminum shield 12, a filler 13, a temperature sensor 14, a flexible flat cable 15, and a filler 16. An actual temperature detection sensor cable 10 is, for example, a cable several hundred meters or several kilometers long, with the temperature sensors 14 shown in Fig. 15 incorporated at 5-meter intervals.

[0009] Each temperature sensor 13 measures the temperature at its installation location and sends this information to the control device. The information to pay attention to here is the change in the measured temperature from a certain point in the past, and this change is used to estimate whether or not a heat source exists at the installation location. If a fire breaks out in a road tunnel, the multiple temperature sensors 14 can robustly detect temperature changes, making it possible to detect the fire with a certain degree of accuracy. Furthermore, this fire detection system can also detect the growth of the fire. As such, algorithms are also provided for fire detection using conventional temperature cable sensors, and a system that is popular in Europe is capable of detecting a fire with high accuracy within one minute of its occurrence (Patent Document 2).

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-152134 [Patent Document 2] Japanese Patent Application Publication No. 2018-180676 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0011] In Japan, the fire detection time for road tunnels is set at 30 seconds, so there is a demand for faster fire detection while also reducing costs. When detecting a fire by detecting the ignition point from images captured by an infrared camera, if there is a clear ignition and the ignition point is clearly present, the ignition point can be clearly captured in the images captured by the infrared camera, and the fire may be detected early.

[0012] However, there are also problems that need to be improved when detecting fires from images captured by infrared cameras. The first problem is that, due to cost considerations, there is a limit to the number of infrared cameras that can be installed inside a road tunnel, so in order to cover the entire distance of the road tunnel with that number of cameras, the camera's shooting angle must be shallow, and the cameras must be installed with a relatively far field of view. However, there are many vehicles traveling inside the road tunnel, and in the event of an emergency such as a fire, if a large truck or other vehicle stops in front, it will interfere with the fire and the infrared camera, so even if there is a fire, it is expected that it will not be captured in the infrared camera's image, or even if it is captured, only a part of it will be captured, not the whole. The second problem is that in actual fires, the precursory stage of a fire cannot be detected. When an accident occurs in a road tunnel, there are often precursory stages where embers are smoldering at the accident site, even if there is no clear, major fire yet. In this precursory stage, even if smoke is rising, there is no clear fire point, so early fire detection that relies on images taken by an infrared camera is difficult.

[0013] Next, when detecting a fire by detecting the outbreak of a fire at the accident scene from images taken by a visible light camera, even if the fire has not yet occurred and the fire is in a precursory stage, it may be possible to detect the fire early if images clearly capturing the accident scene are obtained. However, there are still areas that need improvement when detecting fires from images captured by visible light cameras. The first problem is that, due to cost considerations, the number of visible light cameras that can be installed inside a road tunnel is limited, and in order to cover the entire distance of the road tunnel with that number of cameras, the camera's shooting angle must be shallow, and the cameras must be installed with a relatively distant field of view.However, there are many vehicles traveling inside road tunnels, and in the event of an emergency such as an accident, if a large truck or other vehicle stops in front of the accident site, it will interfere with the accident site and the visible light camera, and it is expected that the accident site will not be captured in the image captured by the visible light camera, or even if it is captured, only a part of it will be captured, not the whole site. The second problem is that when an actual accident occurs, it can be difficult to determine whether an accident has occurred or whether the vehicle is simply stopped.If an accident occurs in a road tunnel and there is an obvious abnormality, such as the vehicle being turned on its side, or smoke is rising, it is easy to determine that an accident has occurred.However, if the vehicle is simply stopped facing the direction of travel, it is still difficult to determine whether the accident will lead to a fire, and early fire detection that relies on images taken by a visible light camera can be difficult.

[0014] Next, when predicting the occurrence of a fire following an accident by capturing temperature rises inside a road tunnel from detection data from a temperature sensor cable, even if a fire has not yet occurred and the fire is in a precursory stage, it may be possible to detect the fire relatively early if a temperature rise inside the road tunnel is detected. A conventional technology for shortening fire detection time while using a temperature sensor cable is disclosed in Japanese Patent Application Laid-Open No. 2018-180676 (Patent Document 2). This is a patent application filed by the present applicant, and is considered an excellent technology that shortens fire detection time to within 30 seconds while using a temperature sensor cable, and is expected to become more widespread in the future. FIG. 16 is a diagram illustrating a fire detection system disclosed in Japanese Patent Application Laid-Open No. 2018-180676. The control unit 13 of the early fire detection system 10 disclosed in Japanese Patent Application Laid-Open No. 2018-180676 calculates the following three values: the magnitude of the time integral value for each temperature detection sensor 11 over a first predetermined period; the magnitude of the spatial integral value of a group of temperature detection sensors surrounding the fire point, which includes a predetermined number of temperature detection sensors including a temperature detection sensor assumed to be the fire point sensor closest to the fire point based on the magnitude of the time integral value; and the magnitude of the concentration ratio calculated from the magnitude of the detection values of the temperature detection sensor assumed to be the fire point sensor in the spatial integral value. The control unit 113 estimates the occurrence of a fire from the results of these three calculations. This enables early fire detection by making a judgment based on the magnitude of the time integral value and the degree of concentration, rather than simply detecting areas with high temperatures.

[0015] The fire detection system described in JP 2018-180676 A (Patent Document 2) is an excellent system, and is expected to be able to detect relatively small fires within 30 seconds. However, depending on the conditions of a tunnel or other location, it can be difficult to set the threshold value for the magnitude of the temperature detection sensor's detection value, which is assumed to represent the fire point in the spatial integral value. If the threshold value is set too low, an alert may be issued indicating a possible fire even when there is no fire. Conversely, if the threshold value is set too high, it may take that much time to issue an alert in the event of a fire.

[0016] In view of the above problems, the present invention aims to provide a road tunnel fire detection system that can detect and estimate fires early by applying technology that collects multiple types of images, such as images taken by infrared cameras and visible light cameras, and organically combines both to make judgments, and technology that dynamically changes the shooting angle to take into account the possibility that traveling vehicles such as large trucks may be interfering with the infrared cameras and visible light cameras. [Means for solving the problem]

[0017] In order to achieve the above object, the road tunnel fire detection system of the present invention is a road tunnel fire detection system characterized by comprising: a plurality of infrared cameras installed at a plurality of locations along the longitudinal direction of the road tunnel; a plurality of visible light cameras installed at a plurality of locations along the longitudinal direction of the road tunnel; and a combination fire detection means that detects a fire by combining information from both the images taken by the plurality of infrared cameras and the images taken by the plurality of visible light cameras. With the above configuration, fire detection based only on images captured by an infrared camera and fire detection based only on images captured by a visible light camera each have their own issues, but by using a combined fire detection means that combines both to perform fire detection, the time required for fire detection judgment processing can be shortened and the accuracy of fire detection can be improved.

[0018] In the above configuration, it is also preferable to devise a layout for the multiple infrared cameras. For example, one may be arranged in pairs, with one camera angled upstream in the direction of travel in the road tunnel and the other camera angled downstream. Alternatively, the multiple visible light cameras may be arranged in pairs, with one camera angled upstream in the direction of travel in the road tunnel and the other camera angled downstream. The infrared cameras and visible light cameras are arranged in pairs, alternating in pairs along the road tunnel. By arranging the cameras so that the viewing area of the infrared camera with an upstream viewing angle overlaps with the viewing area of the visible light camera with a downstream viewing angle, and so that the viewing area of the infrared camera with a downstream viewing angle overlaps with the viewing area of the visible light camera with a downstream viewing angle, blind spots can be reduced and two types of images, infrared images and visible light images, can be obtained.

[0019] Furthermore, in the road tunnel fire detection system of the present invention described above, each of the plurality of infrared photographic cameras can be configured to include a photographing angle changing device that changes the photographing angle of the infrared photographic camera, each of the plurality of visible light photographic cameras can be configured to include a photographing angle changing device that changes the photographing angle of the visible light photographic camera, and an angle change control unit can be configured to transmit an angle change signal that changes the photographing angle to the photographing angle changing device of the infrared photographic camera and the photographing angle changing device of the visible light photographic camera. By equipping this infrared camera with a shooting angle change device, a visible light camera with a shooting angle change device, and an angle change control unit for these, the combined fire detection means can obtain images that are more useful for fire detection using each of the following patterns and combine multiple pieces of information in an appropriate manner during fire detection processing. The first pattern is characterized in that the combined fire detection means is equipped with a fire candidate detection means that detects the presence of fire candidate points with a temperature above a predetermined level and the estimated location of the fire candidate points within the road tunnel from images captured by the multiple infrared imaging cameras, and is equipped with a fire candidate infrared imaging support function that adjusts the imaging angle of the imaging angle change device of the nearby infrared imaging camera via the angle change control unit based on the estimated location of the fire candidate points within the road tunnel detected by the fire candidate detection means. According to this first pattern, when an infrared image of a possible fire spot is obtained from an image captured by an infrared camera, the shooting angles of multiple other infrared cameras are dynamically changed by a shooting angle change device under the control of the fire spot candidate infrared shooting support function, and the area where the fire spot may be located is photographed intensively with multiple infrared cameras, allowing high-quality information to be collected.

[0020] The second pattern is characterized in that the combined fire detection means is equipped with a fire candidate detection means that detects the presence of fire candidate points with a predetermined temperature or higher and the estimated location of the fire candidate points within the road tunnel from images captured by the multiple infrared cameras, and is equipped with a fire candidate visible light photography support function that adjusts the photography angle of the photography angle change device of the nearby visible light photography camera via the angle change control unit based on the estimated location of the fire candidate points within the road tunnel detected by the fire candidate detection means. According to this second pattern, when an infrared image of a possible fire spot is obtained from an image captured by an infrared camera, the shooting angles of the multiple visible light cameras are dynamically changed by the shooting angle change device under the control of the fire spot candidate visible light shooting support function, and the location where the fire spot may be located is photographed intensively with the multiple visible light cameras, and high-quality information captured using visible light, which is different from infrared, can be combined.

[0021] The third pattern is characterized in that the combined fire detection means is equipped with a candidate fire point detection means that detects the presence of a candidate fire point due to changes in visibility within the road tunnel and traffic disruptions including slowing, stopping, and detouring of passing vehicles from images captured by the multiple visible light cameras, and the estimated location of the candidate fire point within the road tunnel, and is equipped with a fire candidate visible light photography support function that adjusts the photography angle of the photography angle change device of the nearby visible light photography camera via the angle change control unit based on the estimated location of the candidate fire point within the road tunnel detected by the candidate fire point detection means. According to this third pattern, when a visible light image of a possible fire is obtained from an image captured by a visible light camera, the shooting angles of multiple other visible light cameras are dynamically changed by a shooting angle change device under the control of the fire candidate visible light shooting support function, and the area where the fire is likely to occur is photographed intensively with multiple visible light cameras, thereby collecting high-quality information.

[0022] The fourth pattern is a pattern in which the combined fire detection means is equipped with a candidate fire outbreak point detection means that detects the presence of candidate fire outbreak points due to changes in visibility within the road tunnel and traffic disruptions including slowing, stopping, and detouring of passing vehicles from images captured by the multiple visible light cameras, and the estimated locations of the candidate fire outbreak points within the road tunnel, and is characterized by being equipped with a fire outbreak point infrared photography support function that adjusts the photography angle of the photography angle change device of the infrared photography camera nearby via the angle change control unit based on the estimated location of the candidate fire outbreak point within the road tunnel detected by the candidate fire outbreak point detection means. According to this fourth pattern, when a visible light image showing the possibility of a fire is obtained from images taken by a visible light camera, the shooting angles of multiple infrared cameras are dynamically changed by a shooting angle change device under the control of the fire candidate infrared photography support function, and the area where the fire is likely to occur is photographed intensively with multiple infrared cameras, and high-quality information photographed with infrared light, which is different from visible light, can be combined.

[0023] Furthermore, the road tunnel fire detection system of the present invention described above can be configured to include a monitor installed at the center and a captured image display means for displaying images captured by the plurality of infrared cameras and images captured by the plurality of visible light cameras in an associated arrangement. With the above configuration, the results of fire detection by the combined fire detection means, which combines images taken by the infrared camera and the visible light camera, can be displayed on a monitor at the center in an easy-to-understand manner, making it easier for the manager to understand.

[0024] Furthermore, in the road tunnel fire detection system of the present invention described above, it is possible to increase the variety of data combined in the combined fire detection means. For example, the road tunnel fire detection system of the present invention described above may be configured to include temperature detection sensors installed at predetermined intervals along the longitudinal direction of the road tunnel, and to obtain measured temperature values at the predetermined intervals and at predetermined time intervals to obtain measured temperature distribution data within the road tunnel, and a temperature anomaly verification unit that detects the presence of temperature variations greater than a predetermined value between the temperature detection sensors in the measured temperature distribution data of the tunnel temperature distribution measurement unit and the positions within the road tunnel where the temperature variations occur, and the combined fire detection means detects fires by combining images taken by the multiple infrared cameras, images taken by the multiple visible light cameras, and information on the temperature variation data of the temperature detection sensors in the tunnel temperature distribution measurement unit. With the above configuration, as a variation of the data to be combined in the combined fire detection means, the combined fire detection means can combine temperature data from a temperature detection sensor in addition to images taken by an infrared camera and an image taken by a visible light camera, and by performing fire detection using a combination of the three, the accuracy of fire detection is also improved.

[0025] Next, the road tunnel fire detection method is a road tunnel fire detection method for detecting the occurrence of a fire inside a road tunnel, and is a combined fire detection method that uses infrared images taken by a plurality of infrared cameras installed at a plurality of locations along the longitudinal direction of the road tunnel and visible light images taken by a plurality of visible light cameras installed at a plurality of locations along the longitudinal direction of the road tunnel, and combines the information from both to detect a fire. With the above method, fire detection based solely on images captured by an infrared camera and fire detection based solely on images captured by a visible light camera each have their own issues, but by applying a combined fire detection method that combines both methods to perform fire detection, the time required for fire detection judgment processing can be shortened and the accuracy of fire detection can be improved. Furthermore, in the above road tunnel fire detection method, it is preferable that each of the multiple infrared cameras is capable of changing the shooting angle of the infrared camera, and that each of the multiple visible light cameras is capable of changing the shooting angle of the visible light camera, and that the angle change is controlled by transmitting an angle change signal that changes the shooting angle to the infrared camera and the visible light camera. By controlling the angle changes by changing the shooting angle of this infrared camera and the visible light camera, and transmitting angle change signals that change these shooting angles, it is possible to obtain images that are more useful for fire detection during the fire detection process in the combined fire detection means, and to combine multiple pieces of information in an appropriate manner. [Effects of the Invention]

[0026] According to the road tunnel fire detection system of the present invention, the time required for determining fire detection can be shortened and the accuracy of fire detection can be improved compared to conventional fire detection based only on images captured by an infrared camera or only on images captured by a visible light camera. Furthermore, according to the road tunnel fire detection system of the present invention, by being equipped with a shooting angle change device for the infrared camera, a shooting angle change device for the visible light camera, and an angle change control unit for those, it is possible to obtain images that are more useful for fire detection in the fire detection process of the combined fire detection means, and to combine multiple pieces of information in an appropriate manner. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a diagram showing an example of the configuration of a road tunnel fire detection system 100 according to the present invention. [Figure 2]FIG. 10 is a diagram simply showing an example of a display on a monitor 180 in accordance with a first pattern arrangement of the photographed image display means 170. [Figure 3] FIG. 10 is a diagram simply showing an example of a display on the monitor 180 in accordance with the second pattern arrangement of the photographed image display means 170. [Figure 4] This is an infrared image captured by the infrared camera 110-2. [Figure 5] FIG. 10 is a diagram showing a monitor screen in which the shooting angle of a nearby infrared camera 110-1 is adjusted to the estimated position of a candidate fire outbreak point. [Figure 6] FIG. 10 is a diagram showing a monitor screen in which the shooting angle of a nearby visible light camera 120-1 is adjusted to the estimated position of a candidate fire outbreak point. [Figure 7] FIG. 10 is a diagram illustrating an example of the configuration of a road tunnel fire detection system 100-2 according to a second embodiment. [Figure 8] FIG. 8 is a diagram simply showing an example of an image taken when the fire in FIG. 7 occurs. [Figure 9] FIG. 10 is a diagram illustrating an example of the configuration of a road tunnel fire detection system 100a according to a third embodiment. [Figure 10] 10 is a diagram showing an example of the configuration of a temperature detection sensor cable 192. FIG. [Figure 11] This figure shows the temperature change over time and space of the temperature sensor cable output. [Figure 12] FIG. 10 is a diagram showing an example of a display on a monitor in a monitoring center. [Figure 13] FIG. 10 is a diagram showing an example of a display on a monitor at a monitoring center immediately after a fire breaks out. [Figure 14] FIG. 10 is a diagram showing an example of a display on a monitor at a monitoring center when a fire has continued for a certain period of time. [Figure 15] 1 is a diagram showing an example of the configuration of a temperature detection sensor cable 10 according to the prior art. [Figure 16] FIG. 1 is a diagram showing a fire detection system disclosed in Japanese Patent Application Laid-Open No. 2018-180676, which is a conventional technology. BEST MODE FOR CARRYING OUT THE INVENTION

[0028] Hereinafter, embodiments of the road tunnel fire detection system of the present invention will be described with reference to the drawings. However, it goes without saying that the scope of the present invention is not limited to the specific applications, shapes, numbers, etc. shown in the following embodiments. Hereinafter, as Example 1, a configuration example of a road tunnel fire detection system 100 that combines images captured by an infrared camera and images captured by visible light is shown. As Example 2, a configuration example in which a pair of infrared cameras and a pair of visible light cameras are arranged in an innovative manner is shown. As Example 3, a configuration example of a road tunnel fire detection system 100a that combines images captured by an infrared camera and images captured by visible light with temperature detection results from a temperature detection sensor is shown. Example 1

[0029] An example of the configuration of the road tunnel fire detection system 100 of the present invention will be described below. FIG. 1 is a diagram showing an example of the configuration of a road tunnel fire detection system 100 according to the present invention. As shown in FIG. 1, the road tunnel fire detection system 100 is configured to include an infrared camera 110, an infrared camera imaging angle change device 111, a visible light camera 120, a visible light camera imaging angle change device 121, an angle change control unit 130, a combined fire detection means 140, a fire point candidate detection means 150, a fire outbreak point candidate detection means 160, a captured image display means 170, and a monitor 180. The infrared camera imaging angle change device 111, the visible light camera imaging angle change device 121, and the angle change control unit 130 are optional components, and it is possible to have none of these components. The following description will be given as an example of a configuration in which these options are incorporated.

[0030] The infrared cameras 110 are installed at multiple locations along the longitudinal direction of the road tunnel. The infrared cameras 110 may be any cameras capable of visualizing infrared light emitted from an object. The infrared images captured by the infrared cameras 110 can be displayed as thermographic images that are colored to indicate high or low temperatures. In this configuration example, each infrared camera 110 is equipped with an infrared camera shooting angle change device 111, and the shooting direction of each infrared camera 110 can be changed based on a signal from the angle change control unit 130. The infrared camera imaging angle change device 111 changes the imaging direction of the infrared camera 110 using an actuator such as a servo motor. It may change only in the vertical direction, only in the horizontal direction, or may be capable of three-dimensional change in both the vertical and horizontal directions.

[0031] The visible light cameras 120 are installed at multiple locations along the longitudinal direction of the road tunnel. Any camera capable of capturing visible light will suffice as the visible light camera 110, but a color camera is preferable because color images captured by the visible light camera 120 contain more information for understanding the state of a fire, accident, etc. than monochrome images. In this configuration example, each visible light imaging camera 120 is also equipped with a visible light imaging camera imaging angle change device 121, and the imaging direction of each visible light imaging camera 120 can be changed based on a signal from the angle change control unit 130. The visible light imaging camera imaging angle change device 121 uses an actuator such as a servo motor to change the imaging direction of the visible light imaging camera 120. It may be capable of only vertical movement, only horizontal movement, or three-dimensional movement in both the vertical and horizontal directions.

[0032] The angle change control unit 130 transmits an angle change signal for changing the imaging angle to the imaging angle change device 111 of the infrared imaging camera 110 and the imaging angle change device 121 of the visible light imaging camera 120. The angle change signal may be a signal that instructs a change only in the up and down direction, a signal that instructs a change only in the left and right direction, or a signal that instructs a change in three dimensions in both the up and down direction and the left and right direction.

[0033] The combined fire detection means 140 is a part that executes a process of detecting a fire by combining information from both the images captured by the multiple infrared cameras 110 and the images captured by the multiple visible light cameras 120 . In this configuration example, the combined fire detection means 140 includes a fire point candidate detection means 150 and a fire outbreak point candidate detection means 160 .

[0034] The fire candidate detection means 150 executes a process to detect the presence of fire candidate points with temperatures above a predetermined level and the estimated locations of the fire candidate points within the road tunnel from images captured by the multiple infrared cameras 110. By incorporating this fire candidate detection means 150, if a small fire that could become a fire due to an accident or the like is captured at an early stage, the combined fire detection means 140 will be able to predict the outbreak of a fire at an early stage.

[0035] The fire outbreak point candidate detection means 160 executes processing to detect the presence of fire outbreak point candidates due to changes in visibility within the road tunnel and traffic disruptions including deceleration, stopping, and detouring of passing vehicles, as well as the estimated locations of the fire outbreak point candidates within the road tunnel, from images captured by the multiple visible light imaging cameras 120. By installing this fire outbreak point candidate detection means 160, even if there are no small fires that could become ignition sources due to an accident or the like, if the visible light cameras capture conditions that suggest the occurrence of an accident at an early stage, the combined fire detection means 140 will be able to predict the outbreak of a fire early.

[0036] In this way, if the combined fire detection means 140 is equipped with both the fire spot candidate detection means 150 and the fire outbreak point candidate detection means 160, it can flexibly combine and make judgments even in cases where a small fire spot has already occurred early on, or in cases where there is no fire spot yet but a situation that suggests an accident has occurred has already occurred. In addition, infrared camera resources and visible light camera resources located nearby can be concentrated via the angle change control unit 130 to detect the estimated positions of fire spot candidates within the road tunnel detected by the fire spot candidate detection means 150 and the estimated positions of fire spot candidates within the road tunnel detected by the fire spot candidate detection means 160.

[0037] In other words, by providing the combined fire detection means 140 or the fire spot candidate detection means 150 with a "fire spot candidate infrared photography support function" and a "fire spot candidate visible light photography support function," it is possible to effectively utilize nearby infrared camera resources and visible light camera resources. The "fire spot candidate infrared photography support function" adjusts the photography angle of the photography angle change device 111 of the infrared photography camera 110 nearby via the angle change control unit 130 with respect to the estimated position of the fire spot candidate in the road tunnel detected by the fire spot candidate detection means 150. By observing the fire spot with the infrared photography camera 110 from multiple angles, it is possible to obtain a large amount of information to grasp the size, shape, and speed of the fire spot expansion, etc.

[0038] Similarly, the "fire spot candidate visible light photography support function" adjusts the photography angle of the photography angle change device 121 of the nearby visible light photography camera 120 via the angle change control unit 130 with respect to the estimated position of the fire spot candidate in the road tunnel detected by the fire spot candidate detection means 150. By observing the fire spot with the visible light photography camera 120 from multiple angles, it is possible to obtain a large amount of information to grasp the situation inside the tunnel, the condition of the vehicles traveling, the scale of the accident, the presence or absence of smoke, etc.

[0039] Next, by providing the combined fire detection means 140 or the potential fire outbreak point detection means 160 with a "potential fire outbreak point infrared photography support function" and a "potential fire outbreak point visible light photography support function," it is possible to effectively utilize nearby infrared camera resources and visible light camera resources. The "fire outbreak point candidate infrared photography support function" adjusts the photography angle of the photography angle change device 111 of the infrared photography camera 110 in the vicinity via the angle change control unit 130 with respect to the estimated position of the fire outbreak point candidate in the road tunnel detected by the fire outbreak point candidate detection means 160. By observing with the infrared photography camera 110 from multiple angles, it is possible that a fire point that is not captured at the photography angle of the infrared photography camera 110 under normal circumstances may be captured at the photography angle of another infrared photography camera 110, making it possible to find the fire early and obtain a large amount of information to understand the size, shape, and speed of the fire's spread, etc.

[0040] Similarly, the "fire outbreak point candidate visible light photography support function" adjusts the photography angle of the photography angle change device 121 of the nearby visible light photography camera 120 via the angle change control unit 130 with respect to the estimated position of the fire outbreak point candidate in the road tunnel detected by the fire outbreak point candidate detection means 160. By observing the fire outbreak point candidate with the visible light photography camera 120 from multiple angles, it is possible to obtain a large amount of information to grasp the actual situation inside the tunnel, the condition of the vehicles traveling, the scale of the accident, the presence or absence of smoke, etc.

[0041] The description of the other components of FIG. 1 continues. Next, the captured image display means 170 is a part that executes the process of displaying on the monitor 180 both the images captured by the multiple infrared cameras 110 and the images captured by the multiple visible light cameras 120 in a corresponding arrangement. There are various possible patterns for the arrangement in which the images captured by the multiple infrared imaging cameras 110 and the images captured by the multiple visible light imaging cameras 120 are associated with each other.

[0042] The first arrangement pattern is an arrangement in which the visible light image taken by visible light camera 120 is arranged above the display screen of monitor 180, and the infrared image taken by infrared camera 110 is arranged below, with the images arranged horizontally in order of points along the tunnel from upstream to downstream. With this arrangement, the images on both the top and bottom are taken at points that are roughly close to each other, and by looking at the images above and below, it is possible to check for the presence or absence of abnormalities in the visible light image and the presence or absence of fire spots in the infrared image. FIG. 2 is a diagram simply showing an example of a display on the monitor 180 according to the first pattern arrangement of the photographed image display means 170. In FIG. 2, the visible light images captured by the visible light camera 120 are arranged on the top side, and the infrared images captured by the infrared camera 110 are arranged on the bottom side. This is a convenient arrangement for maintenance personnel at the center to view the visible light images and infrared images while associating them with each other.

[0043] The second arrangement pattern is an arrangement in which, by time sharing, a group of images collected and arranged from visible light images taken by the visible light camera 120 and a group of images collected and arranged from infrared images taken by the infrared camera 110 are alternately displayed at predetermined intervals. FIG. 3 is a diagram simply showing an example of a display on the monitor 180 according to the second pattern arrangement of the photographed image display means 170. In FIG. 3 is a long-distance road tunnel, and assumes, for example, that there are eight visible light cameras and eight infrared cameras installed. If monitor 180 displays an eight-split image, only four visible light images and four infrared images can be viewed at a glance in the first pattern above, but in the second pattern, eight visible light images are first displayed, and then eight infrared images are displayed after a predetermined time has elapsed (for example, 10 seconds), improving the visibility of the entire tunnel.

[0044] The arrangement in which the images captured by the multiple infrared imaging cameras 110 and the images captured by the multiple visible light imaging cameras 120 are associated with each other is not limited to the above two patterns, and various other patterns are possible. The above is a brief description of each component of the road tunnel fire detection system 100 according to the first embodiment.

[0045] Next, an example of the road tunnel fire detection process of the road tunnel fire detection system 100 will be described in order. Here, we will explain a very simple example in which there are only two infrared cameras 110, infrared camera 110-1 and infrared camera 110-2, and only two visible light cameras 120, visible light camera 120-1 and visible light camera 120-2, as shown in Figure 1. As shown in Figure 1, infrared imaging cameras 110-1 and 110-2, visible light imaging cameras 120-1 and 120-2 are installed at predetermined positions on the upper part of the side walls within the road tunnel, and the default (normal) camera imaging angle is set to face slightly downward and forward, as shown in the figure.

[0046] Both the default (normal) visible light photographed image and the infrared photographed image show the normal state of the road tunnel (not shown). The combined fire detection means 140 does not report or issue any particular abnormality to the center.

[0047] Here, let us assume that a small accident occurs at the location of fire point 1 shown in Figure 4(a), causing a small fire. This fire point 1 is between infrared photography camera 110-1 and infrared photography camera 110-2, but we will assume that infrared photography camera 110-1 is actually closer in terms of distance.

[0048] Fig. 5(a) shows infrared images captured by infrared camera 110-1 and infrared camera 110-2. As shown in Fig. 4(a), a high temperature that is presumed to be a fire spot can be seen in the infrared image captured by infrared camera 110-2. Note that although infrared camera 110-1 is closer to fire spot 1 in terms of distance, in the default state the imaging angle of infrared camera 110-1 is facing forward, and fire spot 1 is not within its imaging angle. As shown in FIG. 4(a), the potential hot spot detection means 150 detects this high temperature generating object as a potential hot spot and notifies the combined fire detection means 140 of this. Here, the combined fire detection means 140 uses its "fire spot candidate infrared photography support function" to input nearby infrared camera resources to the estimated position of fire spot 1. That is, as shown in FIG. 4(b), for the estimated position of the fire spot candidate in the road tunnel detected by the fire spot candidate detection means 150, a signal is transmitted via the angle change control unit 130 to the photography angle change device 111 of the nearby infrared photography camera 110 to adjust its photography angle. Here, a signal is sent to the photography angle change device 111 of the infrared photography camera 110-1 located near fire spot 1 to adjust the photography angle of the infrared photography camera 110-1 to the estimated position of the fire spot. Here, the infrared photography camera 110-1 by default (normally) captures the front of the tunnel, but since the estimated position of fire spot 1 is behind it, the photography angle change device 111 causes the infrared photography camera 110-1 to rotate backwards and adjust the photography angle to face backwards.

[0049] 5(b), the infrared image captured by infrared camera 110-1 is arranged on the left side, and the infrared image captured by infrared camera 110-2 is arranged on the right side. In this example, the "fire spot candidate infrared photography support function" works effectively, and the fire spot that appears small in infrared camera 110-2 appears large in the image captured by infrared camera 110-1. In other words, by observing the fire spot with infrared camera 110 from multiple angles, it is possible to obtain a large amount of information needed to understand the size, shape, and speed of the fire spot expansion, etc. In this example, it is assumed that the visible light imaging camera 120-2 also captures an image of the tunnel interior that suggests an accident (not shown). It is also assumed that the potential fire location detection means 160 detects the location as a potential fire location.

[0050] The combined fire detection means 140 further includes a "fire outbreak point candidate visible light photography support function" that, with respect to the estimated position of the fire outbreak point candidate in the road tunnel detected by the fire outbreak point candidate detection means 160 (here, assumed to be the same position as fire spot 1), adjusts the photography angle of the photography angle change device 121 of the nearby visible light photography camera 120 via the angle change control unit 130, as shown in FIG. 4(b). In this example, too, a signal is sent to the photography angle change device 121 of the visible light photography camera 120-1 located near the estimated position of the fire outbreak point candidate (here, assumed to be the same position as fire spot 1), so that the photography angle of the visible light photography camera 120-1 is adjusted to the estimated position of the fire outbreak point candidate. In this example, the visible light photography camera 120-1 by default (normally) captures the front of the tunnel, but because the estimated position of the fire outbreak point candidate is behind it, the photography angle change device 121 causes the visible light photography camera 120-1 to rotate backwards and adjust the photography angle to face backwards.

[0051] 6, the visible light images captured by visible light camera 120-1 are arranged on the left side of the upper row, the visible light images captured by visible light camera 120-2 on the right side of the upper row, and the infrared images captured by infrared camera 110-1 on the left side of the lower row, and the infrared images captured by infrared camera 110-2 on the right side of the lower row. In this example, both the "fire spot candidate infrared photography support function" and the "fire outbreak point candidate visible light photography support function" work effectively, and the fire spot and accident that were previously shown small are now shown large. In other words, by observing the fire spot from multiple angles with the infrared imaging camera 110, it is possible to obtain a large amount of information to grasp the size, shape, and speed of the fire spot expansion, etc. Also, by observing the potential fire spot from multiple angles with the visible light imaging camera 120, it is possible to obtain a large amount of information to grasp the actual situation inside the tunnel, the condition of the vehicles traveling, the scale of the accident, the presence or absence of smoke, etc. Example 2

[0052] As a second embodiment, an example in which the arrangement of the infrared imaging camera and the visible light imaging camera is devised will be described. 7 is a diagram showing a configuration example of a road tunnel fire detection system 100-2 according to Example 2. The configuration of each unit may be the same as that of Example 1, but also in Example 2, the imaging angle change device 111 of the infrared imaging camera, the imaging angle change device 121 of the visible light imaging camera, and the angle change control unit 130 are optional components, and Example 2 will be described as a configuration example without these components. In FIG. 7, each of the infrared imaging camera 110 and the visible light imaging camera 120 may be the same as those in the first embodiment, but in the second embodiment, they are paired. As simply shown in Figure 7, the multiple infrared photographic cameras 110 are arranged in pairs, with infrared photographic camera 110-1a set at a photographing angle on the upstream side of the road tunnel in the direction of travel, and infrared photographic camera 110-1b set at a photographing angle on the downstream side. This pair is lined up along the road tunnel. Similarly, the multiple visible light photographing cameras 110 are arranged in pairs, with one visible light photographing camera 120-1a having a photographing angle set on the upstream side of the traveling direction in the road tunnel and the other visible light photographing camera 120-1b having a photographing direction set on the downstream side. This pair is lined up along the road tunnel.

[0053] 7 simply shows a pair of infrared cameras 110-1a, b and a pair of visible light cameras 120-1a, b, but if the road tunnel is long, they are arranged alternately. That is, the arrangement is as follows: infrared cameras 110-1a, b → visible light cameras 120-1a, b → infrared cameras 110-2a, b → visible light cameras 120-2a, b → infrared cameras 110-3a, b → visible light cameras 120-3a, b, and so on.

[0054] In this case, the infrared camera 110 and the visible light camera 120 are arranged so that their viewing areas overlap, with the infrared camera 110 and the visible light camera 120 being set at an angle upstream and downstream, respectively. Similarly, the infrared camera 110 and the visible light camera 120 are arranged so that their viewing areas overlap, with the visible light camera 120 and the visible light camera 120 being set at an angle downstream and upstream, respectively. In Figure 7, as an example of the relationship between them, the field of view of infrared camera 110-1b, which has a shooting angle set on the downstream side, and the field of view of visible light camera 120-1a, which has a shooting angle set on the upstream side, are arranged so that they overlap. By arranging the viewing areas so that they overlap, as shown in Figure 7, blind spots are reduced and different types of images, namely infrared images and visible light images, can be obtained, ensuring diversity in surveillance.

[0055] Here, it is assumed that a fire has broken out as shown in FIG. 7(b). This fire is in the field of view of infrared camera 110-1b, which has a downstream shooting angle, and in the field of view of visible light camera 120-1a, which has an upstream shooting angle, and images can be obtained by both cameras. FIG. 8 shows a simple example of an image taken when a fire breaks out as shown in FIG. 7(b). As shown in Fig. 8, two types of images capturing the fire are obtained: an infrared image captured by infrared camera 110-1b with a downstream shooting angle, and a visible light image captured by visible light camera 120-1a with a upstream shooting angle. The combined fire detection means 140 can make a more multifaceted, earlier, and more accurate determination of the presence or absence of a fire from the infrared and visible light images.

[0056] Note that the above configuration example has been described as an example in which the infrared camera shooting angle change device 111, the visible light camera shooting angle change device 121, and the angle change control unit 130 are not incorporated, but the configuration may also be such that these options are incorporated, there are a pair of infrared cameras 110, and a pair of visible light cameras 120, and each camera or the pair as a whole can change its angle. Example 3

[0057] As a third embodiment, a configuration example of a road tunnel fire detection system 100a will be described, in which temperature detection results from a temperature detection sensor are combined with images captured by an infrared camera and images captured by visible light. FIG. 9 is a diagram illustrating a configuration example of a road tunnel fire detection system 100a according to a third embodiment of the present invention. As shown in FIG. 9, the road tunnel fire detection system 100 is configured to include an infrared camera 110, an infrared camera imaging angle change device 111, a visible light camera 120, a visible light camera imaging angle change device 121, an angle change control unit 130, a combined fire detection means 140, a potential fire point detection means 150, a potential fire outbreak point detection means 160, a captured image display means 170, a monitor 180, and in addition, a tunnel temperature distribution measurement unit 190.

[0058] The tunnel temperature distribution measuring unit 190 is configured to include a temperature detection sensor 191 and a temperature detection sensor cable 192. The tunnel temperature distribution measurement unit 190 acquires measured values from each of the temperature detection sensors 191 at predetermined time intervals to obtain measured data on the temperature distribution inside the road tunnel. The number of temperature detection sensors 191 and the intervals at which they are disposed are not limited. The temperature detection sensors 191 are sensors capable of detecting temperature, such as semiconductor temperature sensors, and are provided at predetermined intervals on a temperature detection sensor cable 192.

[0059] The temperature detection sensor cable 192 is laid inside the road tunnel along the length of the road tunnel, and temperature detection sensors 191 are embedded inside the cable at regular intervals (standard 5m or 8m), allowing measurement data to be collected from the temperature detection sensors 191 over a spatial spread along the length of the road tunnel. Conventional fire alarms are installed at 50m intervals, but the temperature sensor cable is installed at 5m intervals, allowing for more precise fire control.

[0060] Fig. 10 is a diagram showing an example of the configuration of a temperature detection sensor cable 192. Fig. 10(b) shows an enlarged view of the portion where the temperature sensor 191 is incorporated. In the example configuration shown in Fig. 10(b), the temperature detection sensor cable 192 includes a cable jacket 1921, an aluminum shield 1922, a filler 1923, the temperature detection sensor 191, a flexible flat cable 1925, and a filler 1926. The actual temperature detection sensor cable 192 is, for example, a cable having a length of several hundred meters or several kilometers, and the temperature detection sensors 191 shown in Fig. 10 are incorporated at 5-meter intervals. Each temperature detection sensor 191 measures the temperature at the installation location, and the temperature measurement data is linked to the temperature data at the installation location, that is, the spatial spread, and collected by the tunnel temperature distribution measurement unit.

[0061] The tunnel temperature distribution measurement unit 190 acquires temperature distribution data within the road tunnel from temperature measurement data collected from each temperature detection sensor 191 of the temperature detection sensor cable 192. In addition, in this example, the processing of temperature data in the combined fire detection means 140 will be described as collecting and assembling the temperature data obtained from each temperature detection sensor 191 as temperature distribution data within the tunnel, taking into account the spatial spread within the tunnel.

[0062] As shown in Figure 9, the combined fire detection means 140 verifies the temperature distribution by comparing the infrared image taken by the infrared camera 110, the visible light image taken by the visible light camera 120, and the temperature distribution measurement data obtained by the tunnel temperature distribution measurement unit 190.

[0063] Hereinafter, a flow of the process of determining whether a fire has occurred in the combined fire detection means 140 according to the third embodiment will be described. The combined fire detection means 140 performs fire detection processing based on the temperature distribution measurement data from the tunnel temperature distribution measurement unit 190. First, based on the magnitude of the time integral value for each temperature detection sensor 191, a location where a fire may occur is estimated. As will be described later, the road tunnel fire detection system 100 of the present invention shortens the time range for time integration, i.e., the first predetermined period, in order to detect fires early, but instead eliminates non-fires that are raised as candidates for fire occurrence by combining multiple other evaluation methods.

[0064] For example, if it is desired to estimate the occurrence of a fire within 30 seconds, the time range for time integration, i.e., the first predetermined period, must be set to 30 seconds or less. Here, as an example, the first predetermined period is set to 30 seconds. Over these 30 seconds, the time integral values of the measurement results of each temperature detection sensor 191 are calculated, and those that exceed the first threshold value are selected. Here, when setting the first threshold, there are several factors that affect the integral value of the temperature rise when a fire occurs, such as the size (width) of the road tunnel, the height of the road tunnel, the length of the road tunnel, the season, the time of day, the weather, and the traffic volume, so the threshold must be set taking these various conditions into consideration. Here, the following road tunnel fire experiment is conducted to set the first threshold value.

[0065] A simulated fire experiment was conducted by attaching temperature sensor cables (temperature detection sensors spaced 4m apart) to the top of the wall of a road tunnel with a cross-sectional area of 70m2 as the fire point. In this experiment, normal heptane, which produces little smoke, was used in a fire pan with an area of 1m2 and a capacity of 12 liters. The location of the fire pan, which would serve as the ignition point of the simulated fire, was adjusted so that it was directly below temperature detection sensor number 13 in the center of the road tunnel (on the center line). Here, the temperature detection sensor closest to the ignition point of the simulated fire may be abbreviated as the "ignition point sensor."

[0066] Figure 11 shows the temperature change over time and space in the temperature sensor cable output. As shown in Figure 11, the temperature rises slowly at first, and after about 300 seconds, the temperature rise stops and remains almost constant. Figure 11 shows that a large peak is observed near the fire point sensor, and that the temperature does not rise as much at further locations. This shows that the temperature rise near the fire point sensor is more pronounced than in other locations, confirming the validity of fire detection using the temperature sensor cable 120.

[0067] Here, if the predetermined time is set to 30 seconds, there may be cases where a sufficient temperature change cannot be obtained, so the detection threshold is set to about 0.3 degrees. However, if a fire is detected when the integrated value of the temperature rise of the temperature detection sensor 191 over 30 seconds exceeds 0.3°C in order to achieve fire detection after 30 seconds, there is a risk that a temperature rise pattern caused by other factors that do not cause a fire will also be detected as a fire. Therefore, in addition to the temperature change (time integral value) for 30 seconds based on the temperature distribution measurement data from the tunnel temperature distribution measurement unit 190, the combined fire detection means 140 combines the infrared images from the infrared camera 110, the visible light images from the visible light camera 120, the combined fire detection means 140, the potential fire point detection means 150, and the potential fire outbreak point detection means 160 to make a comprehensive judgment on fire detection.

[0068] Next, an example of display on the monitor 180 at the monitoring center by the captured image display means 170 will be shown. 12 is a diagram showing an example of a display on a monitor at a monitoring center. On the upper left side, a visible light image captured by visible light camera 120 is displayed as a set, and on the right side, an infrared image captured by infrared camera 110 is displayed as a set. On the lower side, temperature distribution measurement data from tunnel temperature distribution measurement unit 190 installed in the road tunnel is displayed.

[0069] FIG. 13 shows an example of a display on a monitor at a monitoring center immediately after a fire breaks out. When a fire breaks out, the actual temperature at the fire site rises, and this change is reflected in the temperature distribution measurement data of the tunnel temperature distribution measurement unit 190 on the screen. However, the fire site has not yet appeared in the infrared image taken by the infrared camera 110 on the upper right, and a parked vehicle is visible in the visible light image taken by the visible light camera 120 on the left, with smoke rising from the vehicle. In this example, a potential fire site is detected by the potential fire site detection unit 160 of the combined fire detection unit 140, and a signal is transmitted via the angle change control unit 130 to the infrared camera shooting angle change device 111 and the visible light camera shooting angle change device 121, which change the shooting angles of the nearby infrared cameras 110 and visible light cameras 120 so that they are directed toward the fire site, thereby utilizing the resources of the infrared cameras 110 and visible light cameras 120 other than those of the tunnel temperature distribution measurement unit 190.

[0070] Figure 14 shows an example of a display on the monitor 180 at the monitoring center after a fire has continued for a certain period of time. The temperature distribution measurement data from the tunnel temperature distribution measurement unit 190 shows significant changes. The infrared image captured by the infrared camera 110 on the upper right shows the location of the fire. Furthermore, the visible light image captured by the visible light camera 120 on the left shows a parked vehicle that appears to be an accident vehicle, with thick smoke rising from the vehicle. At this point in Figure 14, the combined fire detection unit 140 determines that the likelihood of a fire has increased and issues a fire detection alert and sends information about the fire's location to the monitoring screen function. As a result, an alert indicator lights up in the upper right corner of the screen. At the same time, the monitoring camera closest to the fire's location is selected and displayed. This function accurately conveys the fire situation to the operator and appropriately supports their judgment.

[0071] As described above, the road tunnel fire detection system 100a according to the third embodiment of the present invention utilizes the structural advantage of having temperature sensors arranged at regular intervals, and the combined fire detection means 140 can perform early fire detection by combining the temperature distribution measurement data from the tunnel temperature distribution measurement unit 190, the infrared images taken by the infrared camera 110, and the visible light images taken by the visible light camera 120.

[0072] While the preferred embodiment of the road tunnel fire detection system of the present invention has been illustrated and described above, it will be understood that various modifications can be made without departing from the technical scope of the present invention. [Industrial Applicability]

[0073] The road tunnel fire detection system of the present invention can be widely applied as a road tunnel fire detection system in road tunnels. [Explanation of symbols]

[0074] 100 Road Tunnel Fire Detection System 110 Infrared Camera 111 Infrared camera angle change device 120 Visible Light Camera 121 Visible light camera angle change device 130 Angle change control section 140 Combined fire detection means 150 Fire point candidate detection means 160 Fire occurrence point candidate detection means 170 Photographed image display means 180 monitors 190 Tunnel temperature distribution measurement section 191 Temperature detection sensor 192 Temperature detection sensor cable

Claims

1. A road tunnel fire detection system that detects a fire outbreak in a road tunnel, a plurality of infrared photographic cameras installed at a plurality of locations along the longitudinal direction of the road tunnel; a plurality of visible light photographing cameras installed at a plurality of locations along the longitudinal direction of the road tunnel; a combined fire detection means for detecting a fire by combining information from both the images captured by the plurality of infrared cameras and the images captured by the plurality of visible light cameras; In the arrangement of the plurality of infrared photographic cameras, one is arranged in a pair with a photographing angle set on the upstream side of the traveling direction in the road tunnel and the other with a photographing direction set on the downstream side, In the arrangement of the plurality of visible light photographing cameras, one is arranged in a pair with a photographing angle set on the upstream side of the traveling direction in the road tunnel and the other with a photographing direction set on the downstream side, The infrared cameras and the visible light cameras are arranged in pairs alternately along the road tunnel, and are arranged so that the field of view of the infrared cameras whose shooting angles are set upstream of the infrared cameras overlaps with the field of view of the visible light cameras whose shooting angles are set downstream of the visible light cameras, and so that the field of view of the infrared cameras whose shooting angles are set downstream of the infrared cameras overlaps with the field of view of the visible light cameras whose shooting angles are set upstream of the visible light cameras.

2. Each of the plurality of infrared photographic cameras is provided with a photographing angle changing device that changes the photographing angle of the infrared photographic camera; each of the plurality of visible light photographing cameras is provided with a photographing angle changing device that changes the photographing angle of the visible light photographing camera; 2. The road tunnel fire detection system according to claim 1, further comprising an angle change control unit that transmits an angle change signal for changing the shooting angle to the shooting angle change device of the infrared shooting camera and the shooting angle change device of the visible light shooting camera.

3. The combined fire detection means comprises a fire spot candidate detection means for detecting the presence of fire spot candidates having a predetermined temperature or higher and the estimated positions of the fire spot candidates within the road tunnel from images captured by the multiple infrared photography cameras, The road tunnel fire detection system according to claim 2, characterized in that the angle change control unit adjusts the shooting angle of the shooting angle change device of the infrared shooting camera with respect to the estimated position of the fire spot candidate in the road tunnel detected by the fire spot candidate detection means.

4. The combined fire detection means comprises a fire spot candidate detection means for detecting the presence of fire spot candidates having a predetermined temperature or higher and the estimated positions of the fire spot candidates within the road tunnel from images captured by the multiple infrared photography cameras, The road tunnel fire detection system according to claim 3, further comprising a fire spot candidate visible light photography support function that adjusts the photography angle of the photography angle change device of the visible light photography camera in the vicinity of the estimated position of the fire spot candidate in the road tunnel detected by the fire spot candidate detection means via the angle change control unit.

5. the combined fire detection means comprises a potential fire outbreak point detection means for detecting, from images captured by the plurality of visible light imaging cameras, the presence of a potential fire outbreak point due to a change in visibility in the road tunnel, a traffic disorder including deceleration, stopping, or detouring of passing vehicles, and an estimated location of the potential fire outbreak point within the road tunnel; The road tunnel fire detection system according to claim 3, characterized in that the angle change control unit adjusts the shooting angle of the shooting angle change device of the visible light shooting camera with respect to the estimated position of the fire outbreak point candidate in the road tunnel detected by the fire outbreak point candidate detection means.

6. the combined fire detection means comprises a potential fire outbreak point detection means for detecting, from images captured by the plurality of visible light imaging cameras, the presence of a potential fire outbreak point due to a change in visibility in the road tunnel, a traffic disorder including deceleration, stopping, or detouring of passing vehicles, and an estimated location of the potential fire outbreak point within the road tunnel; The road tunnel fire detection system according to claim 3, further comprising a fire candidate infrared photography support function that adjusts the photography angle of the photography angle change device of the infrared photography camera in the vicinity of the estimated position of the fire outbreak point candidate in the road tunnel detected by the fire outbreak point candidate detection means via the angle change control unit.

7. The monitor installed at the center 7. A road tunnel fire detection system according to claim 1, further comprising an image display means for displaying images taken by a plurality of the infrared cameras and images taken by a plurality of the visible light cameras in an array in association with each other.

8. a tunnel temperature distribution measurement unit in which temperature detection sensors are installed at predetermined intervals along the longitudinal direction of the road tunnel, and which obtains actual temperature measurement values at the predetermined intervals and at predetermined time intervals to obtain temperature distribution measurement data inside the road tunnel; a temperature anomaly verification unit that detects the presence of a temperature variation of a predetermined value or more between the temperature detection sensors in the temperature distribution measurement data of the tunnel temperature distribution measurement unit and the position within the road tunnel where the temperature variation occurs; 8. A road tunnel fire detection system according to claim 1, wherein the combined fire detection means detects a fire by combining images taken by a plurality of the infrared cameras, images taken by a plurality of the visible light cameras, and information on temperature variation data of the temperature detection sensors of the tunnel temperature distribution measurement unit.

9. A road tunnel fire detection method for detecting a fire outbreak in a road tunnel, comprising: Infrared images taken by a plurality of infrared cameras installed at a plurality of locations along the longitudinal direction of the road tunnel; Using visible light images taken by a plurality of visible light cameras installed at a plurality of locations along the longitudinal direction of the road tunnel, In the arrangement of the plurality of infrared photographic cameras, one is arranged in a pair with a photographing angle set on the upstream side of the traveling direction in the road tunnel and the other is arranged with a photographing direction set on the downstream side, In the arrangement of the plurality of visible light photographing cameras, one is arranged in a pair with a photographing angle set on the upstream side of the traveling direction in the road tunnel and the other is arranged with a photographing direction set on the downstream side, A road tunnel fire detection method characterized in that the infrared cameras and the visible light cameras are arranged in pairs alternately along the road tunnel, and the cameras are arranged so that the field of view of the camera whose shooting angle is set upstream of the infrared cameras overlaps with the field of view of the camera whose shooting angle is set downstream of the visible light cameras, and the field of view of the camera whose shooting angle is set downstream of the infrared cameras overlaps with the field of view of the camera whose shooting angle is set upstream of the visible light cameras, thereby performing combined fire detection.

10. Each of the plurality of infrared photographic cameras is capable of changing a photographing angle of the infrared photographic camera, Each of the plurality of visible light imaging cameras is capable of changing an imaging angle of the visible light imaging camera, 10. The road tunnel fire detection method according to claim 9, wherein the angle change signal for changing the imaging angle is transmitted to the infrared imaging camera and the visible light imaging camera to control the angle change.

Images