Flame detection system

Abstract

To provide a flame detection system for reducing erroneous detection of a flame detector due to sunlight.SOLUTION: A flame detection system 100 includes: flame detectors 101 arranged inside a tunnel 104 so as to output a signal corresponding to intensity of light to be emitted from a flame; and cameras 102 arranged on a wall surface on the opposite side of the flame detector 101 so as to face the flame detector 101 and photographing the flame detector 101. A disaster prevention reception board 103 performs: analyzing a camera image received from the camera 102 for photographing the flame detector 101 close to an entrance of the tunnel 104; detecting that sunlight shines on the flame detector 101; and performing sensitivity control to reduce a sensitivity of the flame detector 101 when the sunlight shines on the detector.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a flame detection system. [Background technology]

[0002] Conventionally, a flame detection system for detecting a fire occurring in a tunnel is known. For example, Patent Document 1 describes a disaster prevention monitoring system using an optical fire detector. In this disaster prevention monitoring system, a plurality of fire detectors for monitoring fires in the tunnel are installed at regular intervals on the walls and ceiling of the tunnel, and each fire detector monitors both sides of the tunnel in the longitudinal direction, at least the area up to the adjacent fire detector. That is, in order to monitor fires in the longitudinal direction of the tunnel, the fire detector is provided with separate detection elements for monitoring fires on the left and right sides. In addition, the fire detector detects a fire by receiving light and radiant heat from the flames through a translucent window with a detection element, and sends a fire signal to a disaster prevention receiving panel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-197555 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned fire detectors detect fires by receiving light, so a fire detector installed near the entrance to a tunnel may falsely detect a fire by receiving sunlight. The present invention has been made in consideration of the above circumstances, and has an object to reduce erroneous detection by a flame detector caused by sunlight. [Means for solving the problem]

[0005] In order to solve the above problems, the flame detection system of the present invention comprises a flame detector installed in a tunnel that outputs a signal according to the intensity of light emitted by a flame, and a sensitivity control unit that reduces the sensitivity of the flame detector when sunlight is shining on the flame detector. Effect of the Invention

[0006] According to the present invention, it is possible to reduce false detections of a flame detector caused by sunlight. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 shows an example of a flame detection system. [Diagram 2] FIG. 2 shows an example of the configuration of the flame detector 101. [Diagram 3] FIG. 3 shows an example of the configuration of the disaster prevention receiving panel 103. [Figure 4] FIG. 4 shows an example of sensitivity control. [Diagram 5] FIG. 5 shows an example of sensitivity control. [Figure 6] FIG. 6 shows an example of sensitivity control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 1. Example An embodiment of the present invention will now be described with reference to the drawings. 1-1.Configuration FIG. 1 shows an example of a flame detection system according to an embodiment of the present invention. The flame detection system 100 shown in the figure is installed in a tunnel 104. This tunnel 104 is divided into a number of sections, A to Z.

[0009] The flame detection system 100 is composed of a plurality of flame detectors 101 , a plurality of cameras 102 , and a disaster prevention receiving panel 103 .

[0010] The flame detectors 101 are installed at equal intervals on the inner wall of the tunnel 104 along the direction in which the vehicles are traveling. Each flame detector 101 is a twin-lens type flame detector, and is equipped with a right flame detection section that monitors the section on the right side as seen from the device, and a left flame detection section that monitors the section on the left side. Each flame detector 101 is installed at the boundary between sections and monitors two sections simultaneously. Therefore, one section is monitored by two flame detectors 101 in a redundant manner. The arrows in FIG. 1 indicate the monitoring direction of the flame detectors 101.

[0011] Each flame detector 101 is electrically connected to a disaster prevention receiving panel 103, and transmits a flame detection signal to the disaster prevention receiving panel 103 upon detecting a flame.

[0012] The cameras 102 are installed on the inner wall of the tunnel 104 so as to be able to photograph the flame detector 101 near the entrance of the tunnel 104. Each camera 102 is installed on the wall opposite the flame detector 101 so as to face the flame detector 101 near the entrance.

[0013] Each camera 102 is a visible light camera (in other words, an image sensor). Each camera 102 is electrically connected to a disaster prevention receiving panel 103, and transmits the captured camera image to the disaster prevention receiving panel 103.

[0014] It should be noted that the flame detector 101 near the entrance mentioned here includes not only the flame detector 101 adjacent to the entrance, but also the flame detector 101 that is not adjacent to the entrance but may be exposed to sunlight.

[0015] When the disaster prevention receiving panel 103 receives a flame detection signal from the flame detector 101, it starts a fire pump (not shown) and controls a water spray facility (not shown).

[0016] Furthermore, the disaster prevention receiving panel 103 analyzes the camera image received from the camera 102 and detects that sunlight is hitting the flame detector 101. When the panel detects the reception of sunlight, it controls the flame detector 101 to lower its sensitivity on which sunlight is hitting, thereby preventing false detection caused by sunlight.

[0017] 1-1-1. Flame detector 101 Next, details of the flame detector 101 will be described with reference to Fig. 2. Fig. 2 shows an example of the configuration of the flame detector 101. The flame detector 101 includes a main memory device 201 such as a RAM, an auxiliary memory device 202 such as a HDD, a processor 203 such as a CPU, an input / output interface 204, and a communication interface 205 such as a network card.

[0018] The flame detector 101 also includes long wavelength side optical sensors 206R and 206L and short wavelength side optical sensors 207R and 207L. These optical sensors output signals according to the intensity of the light emitted by the flame. These optical sensors are also connected to the input / output interface 204 via an amplifier 208.

[0019] The long wavelength side optical sensors 206R and 206L are optical sensors that respond with high sensitivity to the long wavelength side wavelength band emitted by a flame (heat source). These optical sensors are, for example, pyroelectric elements. In the following description, the long wavelength side optical sensors 206R and 206L are collectively referred to as "long wavelength side optical sensors 206."

[0020] The short wavelength side optical sensors 207R and 207L are optical sensors that respond with high sensitivity to the short wavelength band emitted by a flame (heat source). These optical sensors are, for example, photodiodes. In the following description, the short wavelength side optical sensors 207R and 207L are collectively referred to as "short wavelength side optical sensors 207."

[0021] The long wavelength side optical sensor 206R and the short wavelength side optical sensor 207R are sensors for detecting a flame occurring in a section on the right side as viewed from the flame detector 101. In contrast, the long wavelength side optical sensor 206L and the short wavelength side optical sensor 207L are sensors for detecting a flame occurring in a section on the left side as viewed from the flame detector 101.

[0022] The amplifier 208 amplifies the signal generated by the light sensor in response to light.

[0023] Various programs are stored in the above-mentioned main memory device 201. These programs are distributable via a non-transitory storage medium or a network such as the Internet. Furthermore, various functions are realized by the processor 203 executing these programs. The realized functions include signal recording units 211R, 211L, fire determination units 212R, 212L, a fire alarm unit 213, and a threshold control unit 214. Each function will be described below.

[0024] The signal recording unit 211R periodically acquires the signal output from the long wavelength side optical sensor 206R and the signal output from the short wavelength side optical sensor 207R. Then, the signal recording unit 211R records the amplitude values ​​of the acquired signals in the auxiliary storage device 202 in association with the current time.

[0025] The signal recording unit 211L periodically acquires the signal output from the long wavelength side optical sensor 206L and the signal output from the short wavelength side optical sensor 207L. Then, the signal recording unit 211L records the amplitude values ​​of the acquired signals in the auxiliary storage device 202 in association with the current time.

[0026] The fire determination unit 212R sequentially reads out the sets of amplitude values ​​recorded by the signal recording unit 211R and executes a fire determination. In this case, the fire determination unit 212R determines whether or not the amplitude value of the signal output from the long wavelength side optical sensor 206R and the amplitude value of the signal output from the short wavelength side optical sensor 207R satisfy a predetermined condition. If the result of this determination is positive, the fire determination unit 212R stores the flame detection data in the auxiliary storage device 202 in association with the current time. On the other hand, if the result of this determination is negative, the fire determination unit 212R stores the flame non-detection data in the auxiliary storage device 202 in association with the current time.

[0027] The flame detection data and the flame non-detection data are also associated with information identifying the detection direction "right" and are stored in the auxiliary storage device 202.

[0028] Here, examples of conditions used by the fire determination unit 212R for fire determination are shown below. (Condition 1) The amplitude value of the signal output from the long wavelength side optical sensor 206 is equal to or greater than the threshold value T1. (Condition 2) The amplitude value of the signal output from the short wavelength side optical sensor 207 is equal to or greater than a threshold value T2. (Condition 3) The ratio of the amplitude value of the signal output from the long-wavelength-side optical sensor 206 to the amplitude value of the signal output from the short-wavelength-side optical sensor 207 is equal to or greater than a threshold value T3 and equal to or less than a threshold value T4 (however, T3 <T4)である。 Note that these conditions are merely examples and may be changed as appropriate.

[0029] The fire determination unit 212R determines that a flame has broken out when all of the above conditions 1 to 3 have been satisfied a predetermined number of times or more within a past predetermined length of time (for example, 10 seconds).

[0030] Next, the fire determination section 212L will be described. The fire determination unit 212L sequentially reads out the sets of amplitude values ​​recorded by the signal recording unit 211L and executes a fire determination. In this case, the fire determination unit 212L determines whether or not the amplitude value of the signal output from the long wavelength side optical sensor 206L and the amplitude value of the signal output from the short wavelength side optical sensor 207L satisfy a predetermined condition. If the result of this determination is positive, the fire determination unit 212L stores the flame detection data in the auxiliary storage device 202 in association with the current time. On the other hand, if the result of this determination is negative, the fire determination unit 212L stores the flame non-detection data in the auxiliary storage device 202 in association with the current time.

[0031] The flame detection data and the flame non-detection data are also associated with information identifying the detection direction "left" and are stored in the auxiliary storage device 202.

[0032] The conditions used by the fire determination unit 212L for fire determination are the same as those used by the fire determination unit 212R. The fire determination unit 212L determines that a flame has broken out when all of the above conditions 1 to 3 have been met a predetermined number of times or more within a predetermined time period (for example, 10 seconds) in the past.

[0033] Next, the fire alarm unit 213 will be described. While the fire detection data is stored as the latest data in the auxiliary storage device 202, the fire alarm unit 213 continuously transmits a fire detection signal to the disaster prevention receiving panel 12. The transmitted fire detection signal includes information for identifying the detection direction.

[0034] The threshold control unit 214 controls the sensitivity of the flame detector 101 by controlling the above-mentioned thresholds T1 to T4. Specifically, when the threshold control unit 214 receives a sensitivity reduction instruction from the disaster prevention receiving panel 103, it increases the above-mentioned thresholds T1 to T3 by a predetermined ratio and decreases the above-mentioned threshold T4 by a predetermined ratio. This reduces the sensitivity of the flame detector 101. Furthermore, when the threshold control unit 214 receives a sensitivity return instruction from the disaster prevention receiving panel 103, it returns the increased thresholds T1 to T4 to their original values. This returns the sensitivity of the flame detector 101 to its original value.

[0035] Next, the auxiliary storage device 202 will be described. The auxiliary storage device 202 stores optical sensor signal data 221, flame detection / non-detection data 222, and threshold data 223.

[0036] 1-1-2. Disaster prevention receiving panel 103 Next, details of the disaster prevention receiving panel 103 will be described with reference to Fig. 3. Fig. 3 shows an example of the configuration of the disaster prevention receiving panel 103. The disaster prevention receiving panel 103 includes a main memory device 301 such as a RAM, an auxiliary memory device 302 such as a HDD, a processor 303 such as a CPU, an input / output interface 304, and a communication interface 305 such as a network card.

[0037] The disaster prevention receiving panel 103 also includes a display 306, an operation unit 307, and a speaker 308. These devices are each connected to the input / output interface 304.

[0038] Various programs are stored in the above-mentioned main memory device 301. These programs are distributable via a non-transitory storage medium or a network such as the Internet. Furthermore, various functions are realized by the processor 303 executing these programs. The realized functions include an image recording unit 311, a light receiving detection unit 312, a sensitivity control unit 313, a display control unit 314, and a sound control unit 315. Each function will be described below.

[0039] The image recording unit 311 periodically acquires camera images from each camera 102. Then, the image recording unit 311 records the acquired camera images in the auxiliary storage device 302 in association with the identification information of the output source and the current time.

[0040] The light receiving detection unit 312 judges whether or not sunlight is hitting the flame detector 101 (in other words, whether sunlight is irradiated onto the flame detector 101) by sequentially reading out and analyzing the camera images recorded by the image recording unit 311. The light receiving detection unit 312 detects, based on this judgment, whether sunlight is hitting the flame detector 101 or whether sunlight is not hitting the flame detector 101. This detection process is executed for each flame detector 101.

[0041] When the light receiving and detecting unit 312 detects that sunlight is shining on the flame detector 101 (i.e., when sunlight is shining on the flame detector 101), the sensitivity control unit 313 lowers the sensitivity of the flame detector 101. This prevents erroneous detection of a fire caused by sunlight.

[0042] After lowering the sensitivity of the flame detector 101, if the light receiving detector 312 detects that the flame detector 101 is not exposed to sunlight, the sensitivity controller 313 returns the sensitivity of the flame detector 101 to its original value.

[0043] When the display control unit 314 receives a flame detection signal from the flame detector 101, it identifies the section in which the flame is detected, and displays on the display 306 a message indicating that a flame has been detected in that section.

[0044] When the sound output control unit 315 receives a flame detection signal from the flame detector 101, it causes the speaker 308 to output an alarm sound.

[0045] Next, the auxiliary storage device 302 will be described. The auxiliary storage device 302 stores camera image data 321 .

[0046] 1-2.Operation Next, a description will be given of the sensitivity control executed by the disaster prevention receiving panel 103. An example of this sensitivity control is shown in Fig. 4. The sensitivity control 400 shown in the figure is executed for each flame detector 101.

[0047] First, the light receiving detection unit 312 of the disaster prevention receiving panel 103 identifies the camera 102 corresponding to the flame detector 101 to be processed, and acquires the camera image of the identified camera 102 from the auxiliary storage device 302 (step 401). At that time, the light receiving detection unit 312 acquires the camera image with the oldest shooting date and time among the unacquired camera images.

[0048] Next, the light receiving detection unit 312 analyzes the acquired camera image and identifies the number of red pixels in the area corresponding to the light receiving surface of the flame detector 101 (in other words, the light receiving window covering the optical sensors) (step 402). The reason for identifying the number of red pixels here is to identify the area of ​​the light receiving surface of the flame detector 101 that is exposed to sunlight. When exposed to sunlight, the light receiving surface of the flame detector 101 appears red. Therefore, by identifying the red pixels in the camera image, it is possible to identify the area of ​​the flame detector 101 that is exposed to sunlight.

[0049] It should be noted that the red pixel referred to here is not limited to a pixel having an RGB value of (255,0,0), but may also include a pixel having a predetermined RGB value that is close to red.

[0050] Next, the light receiving detection unit 312 judges whether the number of identified red pixels is equal to or greater than a threshold value T5 (step 403). If the result of this judgment is that the number of identified red pixels is not equal to or greater than the threshold value T5 (NO in step 403), the light receiving detection unit 312 resets the count value of the counter C1 (step 404) and returns to step 401. On the other hand, if the result of this judgment is that the number of identified red pixels is equal to or greater than the threshold value T5 (YES in step 403), the light receiving detection unit 312 increments the count value of the counter C1 (step 405).

[0051] Next, the light receiving detection unit 312 judges whether the count value of the counter C1 is equal to or greater than a threshold value T6 (step 406). This judgment is made in order to judge whether red pixels equal to or greater than a threshold value T5 have been detected consecutively a number of times equal to or greater than the threshold value T6.

[0052] As a result of this determination, if the count value of counter C1 is not equal to or greater than threshold value T6 (NO in step 406), the light receiving detection unit 312 returns to step 401. On the other hand, if the count value of counter C1 is equal to or greater than threshold value T6 (YES in step 406), the light receiving detection unit 312 resets the count value of counter C1 (step 407). Thereafter, the sensitivity control unit 313 reduces the sensitivity of the flame detector 101 to be processed (step 408). At that time, the sensitivity control unit 313 transmits a sensitivity reduction instruction to the flame detector 101 to be processed.

[0053] In the flame detector 101 that has received this sensitivity reduction instruction, the threshold control unit 214 increases the thresholds T1 to T3 by a predetermined ratio and decreases the threshold T4 by a predetermined ratio, thereby lowering the sensitivity of the flame detector 101. As a result, false detection of a fire caused by sunlight is prevented.

[0054] Next, the light receiving detection unit 312 of the disaster prevention receiving panel 103 acquires the camera image of the camera 102 corresponding to the flame detector 101 to be processed from the auxiliary storage device 302 (step 409). At that time, the light receiving detection unit 312 acquires the camera image with the oldest shooting date and time among the unacquired camera images.

[0055] Next, the light receiving detection unit 312 analyzes the acquired camera image and identifies the number of red pixels in the area corresponding to the light receiving surface of the flame detector 101 (step 410). This identification process is similar to step 402.

[0056] Next, the light receiving detection unit 312 judges whether the number of identified red pixels is less than the threshold value T5 (step 411). If the result of this judgment is that the number of identified red pixels is not less than the threshold value T5 (NO in step 411), the light receiving detection unit 312 resets the count value of the counter C2 (step 412) and returns to step 409. On the other hand, if the result of this judgment is that the number of identified red pixels is less than the threshold value T5 (YES in step 411), the light receiving detection unit 312 increments the count value of the counter C2 (step 413).

[0057] Next, the light receiving detection unit 312 judges whether the count value of the counter C2 is equal to or greater than a threshold value T6 (step 414). This judgment is made to judge whether red pixels less than the threshold value T5 have been detected consecutively a number of times equal to or greater than the threshold value T6.

[0058] As a result of this determination, if the count value of counter C2 is not equal to or greater than threshold value T6 (NO in step 414), the light receiving detection unit 312 returns to step 409. On the other hand, if the count value of counter C2 is equal to or greater than threshold value T6 (YES in step 414), the light receiving detection unit 312 resets the count value of counter C2 (step 415). Thereafter, the sensitivity control unit 313 restores the sensitivity of the flame detector 101 to be processed (step 416). At that time, the sensitivity control unit 313 transmits a sensitivity restoration instruction to the flame detector 101 to be processed.

[0059] In the flame detector 101 that has received this sensitivity restoration instruction, the threshold control unit 214 restores the thresholds T1 to T4 to their original values, thereby restoring the sensitivity of the flame detector 101 to its original values.

[0060] Next, the light receiving detector 312 of the disaster prevention receiving panel 103 executes step 401 again. The above is a description of the sensitivity control 400.

[0061] According to the sensitivity control 400 described above, it is possible to reduce false detections of the flame detector 101 caused by sunlight.

[0062] 2. Variations The above embodiment may be modified as follows. The following modifications may be combined with each other. (1) Variation 1 In the above embodiment, a visible light camera is used to detect that sunlight is hitting the flame detector 101. Alternatively, an infrared camera (in other words, an infrared image sensor) may be used to detect that sunlight is hitting the flame detector 101. In that case, an infrared camera 105 is employed in place of the camera 102 in the above flame detection system 100.

[0063] The infrared cameras 105 are installed on the inner wall of the tunnel 104 so as to be able to photograph the flame detectors 101 near the entrance of the tunnel 104. Each infrared camera 105 is installed on the wall opposite the flame detectors 101 so as to face the flame detectors 101 near the entrance. Each infrared camera 105 is electrically connected to the disaster prevention receiving panel 103 and transmits the captured infrared images to the disaster prevention receiving panel 103.

[0064] When the infrared camera 105 is employed, the disaster prevention receiving panel 103 is provided with an image recording section 311A ​​and a light receiving detection section 312A instead of the image recording section 311 and the light receiving detection section 312. The functions of these sections will be described below.

[0065] The image recording unit 311A ​​periodically acquires infrared images from each infrared camera 105. Then, the image recording unit 311A ​​records the acquired infrared images in the auxiliary storage device 302 in association with the identification information of the output source and the current time.

[0066] The light receiving and detecting unit 312A sequentially reads out and analyzes the infrared images recorded by the image recording unit 311A ​​to determine whether or not sunlight is hitting the flame detector 101 (in other words, whether sunlight is irradiated onto the flame detector 101). The light receiving and detecting unit 312A detects, based on this determination, whether sunlight is hitting the flame detector 101 or whether sunlight is not hitting the flame detector 101. This detection process is executed for each flame detector 101.

[0067] Next, a description will be given of the sensitivity control that is executed when the infrared camera 105 is employed. An example of this sensitivity control is shown in Fig. 5. The sensitivity control 500 shown in the figure is executed for each flame detector 101.

[0068] First, the light receiving detection unit 312A of the disaster prevention receiving panel 103 identifies the infrared camera 105 corresponding to the flame detector 101 to be processed, and acquires an infrared image of the identified infrared camera 105 from the auxiliary storage device 302 (step 501). At that time, the light receiving detection unit 312A acquires an infrared image that has not yet been acquired and that has the oldest shooting date and time.

[0069] Next, the light receiving detection unit 312A analyzes the acquired infrared image and identifies the number of pixels having a temperature equal to or higher than a predetermined temperature in an area corresponding to the light receiving surface of the flame detector 101 (in other words, the light receiving window covering the optical sensors) (step 502). The reason for identifying the number of pixels having a temperature equal to or higher than the predetermined temperature here is to identify the range of the light receiving surface of the flame detector 101 that is exposed to sunlight. When the light receiving surface of the flame detector 101 is exposed to sunlight, its surface temperature rises. Therefore, by identifying pixels having a temperature equal to or higher than a predetermined temperature in the infrared image, the range of the flame detector 101 that is exposed to sunlight can be identified.

[0070] Next, the light receiving detection unit 312A judges whether the specified number of pixels is equal to or greater than the threshold value T7 (step 503). If the result of this judgment is that the specified number of pixels is not equal to or greater than the threshold value T7 (NO in step 503), the light receiving detection unit 312A resets the count value of the counter C3 (step 504) and returns to step 501. On the other hand, if the result of this judgment is that the specified number of pixels is equal to or greater than the threshold value T7 (YES in step 503), the light receiving detection unit 312A increments the count value of the counter C3 (step 505).

[0071] Next, the light receiving detection unit 312A judges whether the count value of the counter C3 is equal to or greater than the threshold value T8 (step 506). This judgment is made to judge whether high temperature pixels equal to or greater than the threshold value T7 have been detected consecutively a number of times equal to or greater than the threshold value T8.

[0072] As a result of this determination, if the count value of counter C3 is not equal to or greater than threshold value T8 (NO in step 506), the light receiving detection unit 312A returns to step 501. On the other hand, if the count value of counter C3 is equal to or greater than threshold value T8 (YES in step 506), the light receiving detection unit 312A resets the count value of counter C3 (step 507). Thereafter, the sensitivity control unit 313 reduces the sensitivity of the flame detector 101 to be processed (step 508). At that time, the sensitivity control unit 313 transmits a sensitivity reduction instruction to the flame detector 101 to be processed.

[0073] In the flame detector 101 that has received this sensitivity reduction instruction, the threshold control unit 214 increases the thresholds T1 to T3 by a predetermined ratio and decreases the threshold T4 by a predetermined ratio, thereby lowering the sensitivity of the flame detector 101. As a result, false detection of a fire caused by sunlight is prevented.

[0074] Next, the light receiving and detecting unit 312A of the disaster prevention receiving panel 103 acquires an infrared image captured by the infrared camera 105 corresponding to the flame detector 101 to be processed from the auxiliary storage device 302 (step 509). At that time, the light receiving and detecting unit 312A acquires an infrared image that has not yet been acquired and that has the oldest captured date and time.

[0075] Next, the light receiving and detecting unit 312A analyzes the acquired infrared image and identifies the number of pixels having a predetermined temperature or higher in the area corresponding to the light receiving surface of the flame detector 101 (step 510). This identification process is similar to step 502.

[0076] Next, the light receiving detection unit 312A judges whether the number of identified high temperature pixels is less than the threshold value T7 (step 511). If the result of this judgment is that the number of identified pixels is not less than the threshold value T7 (NO in step 511), the light receiving detection unit 312A resets the count value of the counter C4 (step 512) and returns to step 509. On the other hand, if the result of this judgment is that the number of identified pixels is less than the threshold value T7 (YES in step 511), the light receiving detection unit 312A increments the count value of the counter C4 (step 513).

[0077] Next, the light receiving detection unit 312A judges whether the count value of the counter C4 is equal to or greater than the threshold value T8 (step 514). This judgment is made to judge whether high temperature pixels less than the threshold value T7 have not been detected consecutively a number of times equal to or greater than the threshold value T8.

[0078] As a result of this determination, if the count value of counter C4 is not equal to or greater than threshold value T8 (NO in step 514), the light receiving detection unit 312A returns to step 509. On the other hand, as a result of this determination, if the count value of counter C4 is equal to or greater than threshold value T8 (YES in step 514), the light receiving detection unit 312A resets the count value of counter C4 (step 515). Thereafter, the sensitivity control unit 313 restores the sensitivity of the flame detector 101 to be processed to its original state (step 516). At that time, the sensitivity control unit 313 transmits a sensitivity restoration instruction to the flame detector 101 to be processed.

[0079] In the flame detector 101 that has received this sensitivity restoration instruction, the threshold control unit 214 restores the thresholds T1 to T4 to their original values, thereby restoring the sensitivity of the flame detector 101 to its original values.

[0080] Next, the light receiving detector 312A of the disaster prevention receiving panel 103 executes step 501 again. The above is a description of the sensitivity control 500. The sensitivity control 500 described above can also reduce false detections of the flame detector 101 caused by sunlight.

[0081] (2) Variation 2 In the above embodiment, an illuminance sensor 106 may be used instead of the camera 102 to detect sunlight hitting the flame detector 101. In that case, the illuminance sensor 106 is installed near the flame detector 101 near the entrance of the tunnel 104. Each illuminance sensor 106 is electrically connected to the disaster prevention receiving panel 103 and transmits the measured illuminance data to the disaster prevention receiving panel 103.

[0082] When the illuminance sensor 106 is employed, the disaster prevention receiving panel 103 includes an illuminance recording unit 316 and a light receiving detection unit 312B instead of the image recording unit 311 and the light receiving detection unit 312. Each function will be described below.

[0083] The illuminance recording unit 316 periodically acquires illuminance data from each illuminance sensor 106. The illuminance recording unit 316 then records the acquired illuminance data in the auxiliary storage device 302 in association with identification information of the output source and the current time.

[0084] The light receiving detection unit 312B determines whether or not sunlight is hitting the flame detector 101 (in other words, whether sunlight is irradiated onto the flame detector 101) based on the illuminance data recorded by the illuminance recording unit 316. The light receiving detection unit 312B detects from this determination whether sunlight is hitting the flame detector 101 or whether sunlight is not hitting the flame detector 101. This detection process is executed for each flame detector 101.

[0085] Next, a description will be given of the sensitivity control that is executed when the illuminance sensor 106 is employed. An example of this sensitivity control is shown in Fig. 6. The sensitivity control 600 shown in the figure is executed for each flame detector 101.

[0086] First, the light receiving and detecting unit 312B of the disaster prevention receiving panel 103 identifies the illuminance sensor 106 corresponding to the flame detector 101 to be processed, and acquires the illuminance data of the identified illuminance sensor 106 from the auxiliary storage device 302 (step 601). At that time, the light receiving and detecting unit 312B acquires the illuminance data that has not yet been acquired and that has the oldest measurement date and time.

[0087] Next, the light receiving detection unit 312B determines whether or not the value of the acquired illuminance data is equal to or greater than the threshold value T9 (step 602). This determination is made in order to determine whether or not the flame detector 101 to be processed is being irradiated with sunlight.

[0088] If the result of this determination is that the value of the acquired illuminance data is not equal to or greater than the threshold value T9 (NO in step 602), the light receiving detection unit 312B resets the count value of the counter C5 (step 603) and returns to step 601. On the other hand, if the result of this determination is that the value of the acquired illuminance data is equal to or greater than the threshold value T9 (YES in step 602), the light receiving detection unit 312B increments the count value of the counter C5 (step 604).

[0089] Next, the light receiving detection unit 312B judges whether or not the count value of the counter C5 is equal to or greater than the threshold value T10 (step 605). This judgment is made to judge whether or not an illuminance equal to or greater than the threshold value T9 has been detected a number of times equal to or greater than the threshold value T10 in succession.

[0090] As a result of this determination, if the count value of counter C5 is not equal to or greater than threshold value T10 (NO in step 605), the light receiving detection unit 312B returns to step 601. On the other hand, as a result of this determination, if the count value of counter C5 is equal to or greater than threshold value T10 (YES in step 605), the light receiving detection unit 312B resets the count value of counter C5 (step 606). Thereafter, the sensitivity control unit 313 reduces the sensitivity of the flame detector 101 to be processed (step 607). At that time, the sensitivity control unit 313 transmits a sensitivity reduction instruction to the flame detector 101 to be processed.

[0091] In the flame detector 101 that has received this sensitivity reduction instruction, the threshold control unit 214 increases the thresholds T1 to T3 by a predetermined ratio and decreases the threshold T4 by a predetermined ratio, thereby lowering the sensitivity of the flame detector 101. As a result, false detection of a fire caused by sunlight is prevented.

[0092] Next, the light receiving and detecting unit 312B of the disaster prevention receiving panel 103 acquires the illuminance data of the illuminance sensor 106 corresponding to the flame detector 101 to be processed from the auxiliary storage device 302 (step 608). At that time, the light receiving and detecting unit 312B acquires the illuminance data that has not been acquired and that has the oldest measurement date and time.

[0093] Next, the light receiving detection unit 312B judges whether the value of the acquired illuminance data is less than the threshold value T9 (step 609). If the result of this judgment is that the value of the acquired illuminance data is not less than the threshold value T9 (NO in step 609), the light receiving detection unit 312B resets the count value of the counter C6 (step 610) and returns to step 608. On the other hand, if the result of this judgment is that the value of the acquired illuminance data is less than the threshold value T9 (YES in step 609), the light receiving detection unit 312B increments the count value of the counter C6 (step 611).

[0094] Next, the light receiving detection unit 312B judges whether the count value of the counter C6 is equal to or greater than the threshold value T10 (step 612). This judgment is made to judge whether an illuminance equal to or greater than the threshold value T9 has not been detected consecutively a number of times equal to or greater than the threshold value T10.

[0095] As a result of this determination, if the count value of counter C6 is not equal to or greater than threshold value T10 (NO in step 612), the light receiving detection unit 312B returns to step 608. On the other hand, as a result of this determination, if the count value of counter C6 is equal to or greater than threshold value T10 (YES in step 612), the light receiving detection unit 312B resets the count value of counter C6 (step 613). Thereafter, the sensitivity control unit 313 restores the sensitivity of the flame detector 101 to be processed to its original state (step 614). At that time, the sensitivity control unit 313 transmits a sensitivity restoration instruction to the flame detector 101 to be processed.

[0096] In the flame detector 101 that has received this sensitivity restoration instruction, the threshold control unit 214 restores the thresholds T1 to T4 to their original values, thereby restoring the sensitivity of the flame detector 101 to its original values.

[0097] Next, the light receiving detector 312B of the disaster prevention receiving panel 103 executes step 601 again. The above is a description of the sensitivity control 600. The sensitivity control 600 described above can also reduce false detections of the flame detector 101 caused by sunlight.

[0098] In this modification, it is assumed that the illuminance sensor 106 is installed near the flame detector 101, but the illuminance sensor 106 may be built into the flame detector 101. In that case, the illuminance data of the illuminance sensor 106 is transmitted from the flame detector 101 to the disaster prevention receiving panel 103.

[0099] (3) Variation 3 In the above embodiment, the thresholds T1 to T4 of the flame detector 101 are increased to reduce the sensitivity of the detector. However, the method of reducing the sensitivity is not limited to this. As another method, the amplification factor of the amplifier 208 may be reduced by a predetermined ratio. This method can also reduce the sensitivity of the flame detector 101.

[0100] (4) Variation 4 In the above embodiment, when the sensitivity control unit 313 reduces the sensitivity of a flame detector 101, the sensitivity control unit 313 may increase the sensitivity of another flame detector 101 adjacent to the flame detector 101. This makes it possible to compensate for the reduction in sensitivity of the former detector.

[0101] 1 as an example, when the sensitivity control unit 313 reduces the sensitivity of the leftmost flame detector 101, it may increase the sensitivity of the second flame detector 101 from the left. This reduces the detection sensitivity of the former detector for section A, while increasing the detection sensitivity of the latter detector.

[0102] When increasing the sensitivity of an adjacent flame detector 101, the sensitivity control unit 313 transmits a sensitivity increase instruction to that flame detector 101. In the flame detector 101 that receives this sensitivity increase instruction, the threshold control unit 214 reduces the thresholds T1 to T3 by a predetermined ratio and increases the threshold T4 by a predetermined ratio. This increases the sensitivity of the flame detector 101.

[0103] When the sensitivity control unit 313 restores the sensitivity of the flame detector 101 whose sensitivity has been reduced, it also restores the sensitivity of the flame detector 101 whose sensitivity has been increased. At that time, the sensitivity control unit 313 also transmits a sensitivity restoration instruction to the flame detector 101 whose sensitivity has been increased. In the flame detector 101 that receives this sensitivity restoration instruction, the threshold control unit 214 restores the thresholds T1 to T4 to their original values. This restores the sensitivity of the flame detector 101 to its original values.

[0104] As a method for increasing the sensitivity, instead of lowering the thresholds T1 to T4, the amplification factor of the amplifier 208 may be increased by a predetermined ratio.

[0105] (5) Variation 5 In the above embodiment, the display control unit 314 may display a message to that effect on the display 306 when sunlight is shining on the flame detector 101. This makes it possible to inform the manager of the possibility of false detection of a fire caused by sunlight.

[0106] As a specific process, when a positive determination is made in step 406 of the sensitivity control 400 described above (in other words, when irradiation of the flame detector 101 with sunlight is detected), the display control unit 314 causes the display 306 to display a sunlight irradiation alert. At that time, the display control unit 314 may also cause the display 306 to display identification information of the flame detector 101 on which sunlight is irradiated.

[0107] After displaying the above alert, if a positive judgment is made in step 414 of the sensitivity control 400 (in other words, if sunlight irradiation of the flame detector 101 is no longer detected), the display control unit 314 stops displaying the above alert.

[0108] The location where the above-mentioned solar irradiation alert and the like are displayed is not limited to the display 306 of the disaster prevention receiving panel 103. The display control unit 314 may control another device communicatively connected to the disaster prevention receiving panel 103 to display the above-mentioned solar irradiation alert and the like on the display of that device.

[0109] (6) Variation 6 In the above embodiment, the sensitivity of the flame detector 101 is reduced to prevent false detection caused by sunlight. However, the method of preventing false detection caused by sunlight is not limited to this. As another method, the fire determination of the flame detector 101 may be disabled. False detection can also be prevented by this method.

[0110] When the flame detector 101 is to be disabled, the disaster prevention receiving panel 103 is provided with a function control unit 317 instead of the sensitivity control unit 313. In addition, the flame detector 101 is provided with a disabling unit 215 instead of the threshold control unit 214.

[0111] When the light receiving detection unit 312 detects that sunlight is shining on the flame detector 101, the function control unit 317 invalidates the fire determination of the flame detector 101. Specifically, the function control unit 317 transmits an invalidation instruction to the flame detector 101 on which sunlight is shining.

[0112] In the flame detector 101 that has received the invalidation instruction, the invalidation unit 215 invalidates the fire determination of the flame detector 101. Specifically, the invalidation unit 215 stops the fire determination by the fire determination units 212R and 212L. As another method, the invalidation unit 215 stops the output of the amplifier 208. As another method, the invalidation unit 215 stops the transmission of the flame detection signal by the fire alarm unit 213. By these methods, the fire determination of the flame detector 101 is invalidated.

[0113] After disabling flame detector 101, if light receiving detection unit 312 detects that sunlight is not shining on flame detector 101, function control unit 317 stops disabling the flame detector 101. Specifically, function control unit 317 transmits a restoration instruction to flame detector 101 that is no longer shining on sunlight.

[0114] In the flame detector 101 that has received the restoration instruction, the invalidation unit 215 stops invalidating the fire determination of the flame detector 101. The above-described modified example also makes it possible to prevent erroneous detection caused by sunlight.

[0115] In this modified example, it is assumed that the fire determination is invalidated by the flame detector 101, but the fire determination may be invalidated on the side of the disaster prevention receiving panel 103. In that case, the disaster prevention receiving panel 103 may be provided with a invalidation unit 318 so that a fire alarm is not output even if a flame detection signal is received from the flame detector 101 to be invalidated.

[0116] (7) Variation 7 In the above embodiment, the arrangement of the functions of the flame detector 101 and the disaster prevention receiving panel 103 may be changed as appropriate. For example, the functions of the fire determination units 212R and 212L of the flame detector 101 may be provided in the disaster prevention receiving panel 103. As another example, some of the functions of the flame detector 101 and the disaster prevention receiving panel 103 may be provided in a device different from these.

[0117] (8) Variation 8 The flame detector 101 in the above embodiment is a dual-wavelength flame detector, but the number of wavelength bands to be detected may be one or three or more.

[0118] (9) Variation 9 In the above embodiment and modified example, in order to reduce the sensitivity of the flame detector 101, the thresholds T1 to T3 are increased by a predetermined ratio, and the threshold T4 is decreased by a predetermined ratio. That is, all the thresholds are changed. However, it is not necessary that all the thresholds are changed. For example, it is also possible to change only one of the thresholds T1 to T4.

[0119] (10) Variation 10 In the above embodiment and modified examples, sensitivity control (see Figs. 4 to 6) is performed for each flame detector 101. This sensitivity control may be performed for each of the left and right detection sections of the flame detector 101. That is, when sunlight is shining only on the left detection section of the flame detector 101, the sensitivity of only the left detection section may be reduced, and when sunlight is shining only on the right detection section of the flame detector 101, the sensitivity of only the right detection section may be reduced. In this way, unnecessary reduction in sensitivity can be avoided.

[0120] When this modified example is adopted, the display control unit 314 of the disaster prevention receiving panel 103 may cause the display 306 to display which of the left and right detection units is being illuminated by sunlight.

[0121] (11) Variation 11 In the above embodiment, the number of red pixels is specified in order to determine the irradiation of sunlight (see step 402 in FIG. 4). The reason for specifying the number of "red" pixels here is that the light receiving surface of the flame detector 101 appears red when exposed to sunlight. However, depending on the time of day or location, the light receiving surface exposed to sunlight may appear orange. Therefore, in order to be able to detect irradiation of sunlight even in such cases, orange pixels may be counted in addition to red pixels. Note that the orange pixels referred to here are not limited to pixels having RGB values ​​(238, 120, 0), but may also include pixels having a predetermined RGB value that is close to orange.

[0122] (12) Variation 12 In the above embodiment, the flame detector 101 performs the fire judgment. However, instead of this embodiment, the fire judgment may be performed by the disaster prevention receiving panel 12. In this case, the flame detector 101 transmits signals output from the long wavelength side optical sensors 206R, 206L and the short wavelength side optical sensors 207R, 207L to the disaster prevention receiving panel 12. The disaster prevention receiving panel 12 includes signal recording units 211R, 211L and fire judgment units 212R, 212L, records the signal transmitted from the flame detector 101, and performs the fire judgment based on the signal. In this modification, the disaster prevention receiving panel 12 performs the fire judgment, and therefore includes a threshold control unit 214.

[0123] (13) Other modifications The present invention is not limited to the above-described embodiments, and includes various modified examples. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the configurations described. It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0124] In addition, the above-mentioned configurations, functions, processing units, processing means, etc. may be realized in part or in whole by hardware, for example, by designing them as integrated circuits. In addition, the above-mentioned configurations, functions, etc. may be realized in software by a processor interpreting and executing a program that realizes each function. Information such as the program, table, file, etc. that realizes each function can be stored in a memory, a recording device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD.

[0125] In addition, the control lines and information lines shown are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. In reality, it can be considered that almost all components are connected to each other. The above-described embodiments disclose at least the configurations described in the claims. [Explanation of symbols]

[0126] 100...flame detection system, 101...flame detector, 102...camera, 103...disaster prevention receiving panel, 211R, 211L...signal recording unit, 212R, 212L...fire judgment unit, 213...fire alarm unit, 214...threshold control unit, 221...optical sensor signal data, 222...flame detection / non-detection data, 223...threshold data, 311...image recording unit, 312...light receiving detection unit, 313...sensitivity control unit, 314...display control unit, 315...sound control unit, 321...camera image data

Claims

1. A flame detector installed in the tunnel that outputs a signal according to the intensity of light emitted by a flame; a sensitivity control unit that reduces the sensitivity of the flame detector when sunlight is shining on the flame detector; A flame detection system comprising:

2. A sensor; a light receiving and detecting unit that detects that sunlight is shining on the flame detector based on an output of the sensor; Further equipped with The sensitivity control unit reduces the sensitivity of the flame detector when the light receiving and detecting unit detects that sunlight is shining on the flame detector.

2. The flame detection system of claim 1 .

3. 3. The flame detection system according to claim 2, wherein the sensor is a visible light camera or an infrared camera, and is installed on an inner wall of the tunnel so as to face the flame detector.

4. and a second flame detector disposed in the tunnel adjacent to the flame detector. The flame detection system according to claim 1 , wherein the sensitivity control section increases the sensitivity of the another flame detector when the sensitivity of the flame detector is decreased.

5. The flame detection system according to claim 1 , further comprising a display control unit that, when sunlight is shining on the flame detector, displays that fact on a display.

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