JPH10143777A - Method for detecting fire in high temperature heat treatment process and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fire detecting method and device for quickly and exactly detecting fire occurrence in the processing process of a heat treated object in a high temperature heat treatment process. SOLUTION: In this fire detecting method, a prescribed visual field range in a high temperature heat treatment process is successively monitored by plural color CCD cameras 10, each picture element of an obtained color video is converted into chromaticity coordinates, only a preliminarily designated chromaticity area is extracted from among monitoring pictures, and the shape or shape change of the chromaticity coordinates is recognized by a fire recognition logic different for each monitoring picture so that fire occurrence can be detected. This device is provided with plural color CCD cameras 10 which monitor a prescribed visual field range in a high temperature heat treatment process, camera switcher 11 which switches color video pictures in each constant time, picture processor 12 which converts each picture element of the color video into the chromaticity coordinates, extracts only the chromaticity area to be monitored, and detects the shape or shape change of the chromaticity coordinates according to the logic corresponding to the monitoring area, and warning device 13 which detects the fire occurrence, and outputs a warning signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a process for industrially subjecting a member such as a metal or ceramics to high-temperature heat treatment. The present invention relates to a fire detection method and a fire detection device in a high-temperature heat treatment step capable of quickly and accurately detecting the occurrence of a fire, for example, when a fire is caused by contact with an object.

[0002]

2. Description of the Related Art Conventionally, as a system for monitoring an abnormal situation such as a fire using a CCD camera, for example, a CCD camera for capturing an image of a monitoring unit, a plurality of image memories for storing image information of the camera, a CCD camera, and the like. The CCD camera normally includes an infrared cut filter that passes only light having a wavelength equal to or less than a specific wavelength, and a plurality of infrared cut filters that pass through the filter. When a change in luminance between images over time or a difference between images occurs, only light of a specific wavelength or less passes,
Alternatively, a method is provided in which a filter that cuts only light in a specific wavelength band is switchably mounted (Japanese Patent Publication No. 3-65075).
Or a fire equipped with a light source that radiates infrared light and a CCD that is sensitive to infrared light, and a Fresnel lens made of polyethylene that transmits infrared light and transmits infrared light to the CCD. Detection device
No. 241094) has been proposed. However,
The former uses a monochrome CCD camera that captures only luminance signals, and the infrared filter targets only high-temperature objects, so even if light in a specific wavelength band is cut off, natural light or artificial light sources in any wavelength range will be used. There are limits to preventing malfunction. On the other hand, the latter is a method of optically detecting the attenuation of infrared rays due to smoke filling the space, and does not discriminate a flame by image processing.

As fire detection means using image processing by a color CCD camera, an image pickup means for picking up an image of a monitoring area and a flame signal in a range where a luminance signal included in the image grasped by the image pickup means exceeds a predetermined level. Flame contour extracting means for extracting as a contour, temperature detecting means for detecting a temperature distribution in at least the flame contour extracted by the flame contour extracting means, distance measuring means for measuring a distance to a fire source, and flame contour extracting means Radiant energy calculating means for calculating the radiant energy from the fire source based on the distribution temperature in the flame contour and the distance to the fire source extracted in There has been proposed an apparatus having a flame judgment means for judging a fire based on the result (Japanese Patent Laid-Open No. 5-20564). In this technology, R captured by a color CCD camera
Although the GB signal is image-processed, it has a problem that it is largely affected by disturbance and easily leads to erroneous recognition determination because only the light amount ratio of RGB is targeted.

On the other hand, as a device for extracting an image of a designated color from a video signal picked up by a color image pick-up device, an RGB signal from a color CCD camera is used by a computer to calculate hue, saturation, brightness, tone angle, tone length, and the like. And a method for determining a color order by extracting a color image by comparing with a reference color (Japanese Patent Publication No. 6-70590, and
-92401, 7-49269, 7-198491, etc.). According to this device, the reference color can be extracted quickly and easily, but its application to detection of fire occurrence has not been elucidated.

[0005]

Generally, in the process of heat-treating an intermediate member such as metal or ceramics by a heating furnace in a parts factory, for example, the process of heat-treating steel members such as gears, various rods, and springs, a heat treatment process is performed. The heat treatment member ignites due to a trouble, drops from the transfer device to the floor while the high temperature heat treatment member moves, or comes in contact with easily combustible materials such as oil, paper, plastic, and wood adhering to the floor or equipment. May ignite and cause fire. When performing fire detection in such an environment, it is often difficult to distinguish between the glow emitted from the high-temperature heat-treated material in the monitoring area and the flame leaking from the heating furnace, and the flame caused by the fire. If the heat treatment equipment is complex and lighting and extraneous light are present irregularly, these ambient lights may be mistaken for a fire.

The present inventors have conducted research on a means for accurately detecting the occurrence of a fire in such an environment, and as a result, the color obtained by monitoring the high-temperature heat treatment process with a plurality of color CCD cameras. When the image is converted to chromaticity coordinates, focusing on the fact that the chromaticity of the high-temperature heat-treated object is different from that of disturbance light such as illumination or extraneous light, only the chromaticity region of the heat-treated object is separated. It was found that the occurrence of a fire could be accurately detected from the behavior of the chromaticity region.

The present invention has been developed on the basis of this finding. The object of the present invention is to provide a method for industrially performing high-temperature heat treatment of a member such as a metal or ceramic in order to prevent a fire caused by ignition of a heat-treated material and to use a high-temperature heat-treated material. By distinguishing it from the glowing red light, the leaking flame of the heating furnace, or the extraneous light such as lighting and sunlight,
It is an object of the present invention to provide a fire detection method and device capable of accurately detecting a fire.

[0008]

According to the present invention, there is provided a method for detecting a fire in a high-temperature heat treatment step according to the present invention, wherein a plurality of color CCD cameras sequentially monitor a predetermined visual field range of the high-temperature heat treatment step. Each pixel of the obtained color image is converted into chromaticity coordinates, only the chromaticity area specified in advance is extracted from the monitoring image, and the shape or shape change of the chromaticity coordinate is recognized by a fire recognition logic that differs for each monitoring image. Then, it is characterized by detecting the occurrence of fire.

Further, the fire detection device includes a plurality of color CCD cameras for monitoring a predetermined visual field range in a high-temperature heat treatment process, a camera switcher for switching a color image screen at regular time intervals, and a method for coloring each pixel of a color image. Converts to chromaticity coordinates, extracts only the chromaticity area to be monitored, detects the shape or shape change of chromaticity coordinates according to the logic corresponding to the monitored area, and outputs an alarm signal when a fire is detected And an alarm device that performs the function.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS It is known that heating metals and ceramics to a high temperature emits red light, and the color tone changes according to the heating temperature. The relationship between the temperature and the color tone depends on the locus of the black body in the chromaticity coordinates. Can be indicated by the relationship between the position and the temperature. Focusing on this point, the present invention replaces the color tone of each part in the screen of the color image with the coordinate value (x, y) on the chromaticity coordinates, and the vicinity of the temperature range indicated by the heat-treated object on the blackbody locus. Is recognized as a heat-treated product. The color tone of a fire at the time of fire occurrence always includes the color tone of a heat-treated product despite the distribution of temperature, and the heat treatment material and the flame at the time of the fire occurrence have the same distribution range on the chromaticity coordinates. It belongs to.

Therefore, for example, even when the heat-treated material ignites when it comes into contact with a surrounding object, it is possible to recognize the two at the same time with the same chromaticity value. Since the chromaticity indicated by the extraneous light and the chromaticity indicated by the heat-treated material are greatly different as shown in Table 1, the extraneous light is not erroneously determined to be a fire.

[0012]

[Table 1]

That is, as can be seen from Table 1, the chromaticity coordinates (x,
y) values are generally between (0.5, 0.3) and (0.7, 0.
Since it is in the range of 4) and is clearly different from the chromaticity coordinate values of extraneous light such as sunlight, welding light, and illumination, it is possible to easily extract only the chromaticity region of the flame. In the conversion of each pixel of the color image into chromaticity coordinates, the chromaticity can be calculated at high speed from the three primary color values of the color image by the CPU. The chromaticity coordinate values are R, G, B (R; wavelength 700 nm, G;
It is calculated from the measured values of wavelength 546.3 nm, B; wavelength 435.8 nm).

With respect to the extracted chromaticity region, the shape or shape change of the chromaticity coordinates is recognized for each object within the observation visual field, that is, for each monitoring image according to a different fire recognition logic. (1) High-temperature object recognition and fire recognition logic: To detect a fire that occurs when the heat-treated material comes into contact with oil or a flammable object, it is necessary to first recognize the high-temperature object in the screen from the chromaticity value. . That is, the range of the chromaticity coordinates of the high-temperature object shown in Table 1 is stored in the image processing apparatus in advance, and the chromaticity of each point of the color image is compared with this file to determine a matched part as the heat-treated material. . In this way, a high-temperature region corresponding to the heat-treated material is extracted from the color image. Fire detection is performed using the shape or shape change of the region corresponding to the heat-treated material. Since the flame shows the same chromaticity as the heat-treated material,
For example, when a fire occurs, the high-temperature region rapidly increases, and the shape changes. If the high-temperature region suddenly disappears or suddenly appears from the visual field, it indicates that the heat-treated material or the spark has fallen out of a normal trajectory, and it is determined that the conveyance is abnormal. At this time, the content and degree of the shape change, the rate of the shape change, and the like are set using the arrangement of the device in the visual field, the moving state of the heat-treated object, and the like as parameters.

(2) Combination of process signals: In the high-temperature heat treatment step, there are many objects having similar chromaticity other than the heat-treated material. For example, the inside of the heating furnace has a high temperature, and the flame that leaks from the heating furnace and the chromaticity of the brick inside the heating furnace are the same as those of the heat-treated product. In such a case, the open / close signal of the heating furnace door is transmitted from the process control computer and linked with this control signal, thereby preventing a fire from being erroneously recognized. As the process signal, signals from various sensors and analyzers can be used in addition to the sequence signal from the computer.

The present invention is based on a multi-camera system in which the above-described fire recognition logics are appropriately combined and an optimum logic is configured according to a monitoring area monitored by each camera. It is possible to accurately detect the occurrence of a fire. Further, by applying a logic having a learning function and optimizing the parameters of the fire detection, the reliability can be further improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described in detail below, taking as an example the case where steel members such as gears, rods and springs are continuously subjected to high-temperature heat treatment.

FIG. 2 is a heat treatment process diagram schematically showing a process of transporting the heat-treated member. In FIG. 2, a heat-treated product 2 such as a gear, a rod, or a spring automatically charged into the heating furnace 1 opens and closes a door 3 of the heating furnace 1 at regular time intervals, and the arm 5 of the first robot 4 opens and closes the door. It is taken out while being heated to a high temperature and placed on the intermediate table 6. Next, the heat-treated product 2 on the intermediate table 6 is gripped by the arm 8 of the second robot 7, carried to the cooling table 9, cooled to a predetermined temperature or lower, and then carried out to the product storage area.

In this step, various types of fires occur as described below. Fire near heating furnace door: Flames may leak out of the heating furnace door and come into contact with surrounding objects, causing a fire. Fire due to falling of heat-treated material; heat-treated material grasped by arm of first robot is temporarily placed on intermediate table, and then transported to cooling table by arm of second robot. If unsatisfactory, the heat-treated product will fall on the floor. The heat-treated product that has dropped onto the floor may come into contact with surrounding combustibles or oil adhering to the floor, causing a fire. Intermediate table fire; If the linkage between the first robot and the second robot is not normal, the heat-treated product will not be smoothly transported,
The heat-treated material may accumulate on the intermediate table, causing a fire. Robot fire: If oil adheres to the arm grip of the robot, it may ignite and cause a fire.

For these fire occurrences, the following logic recognizes the fire occurrence. (1) Heating object transfer abnormality monitoring logic (L1): If there is an abnormality in the transfer operation that cannot be determined by the diagnosis function of the robot itself, for example, if the heating object is improperly placed on the intermediate table, the second robot will The heat-treated product cannot be grasped accurately. In such a case, the intermediate stage is monitored by the color CCD camera, and the shape of the heat-treated object is recognized when the heated object is placed on the intermediate stage by a sequence signal from the robot.
It is determined whether the heat-treated product is placed in an appropriate state. Further, when a fire occurs on the intermediate stage, the shape of the high-temperature area changes significantly, so that the occurrence of the fire can be accurately detected.

(2) Ignition monitoring logic (L2) due to the fall of the heat-treated material or sparks onto the floor; the heat-treated material or sparks fall from the transport line and fall on the floor, and the oil adhering to the floor A fire may occur on contact with easily combustible materials. In such a case, when a high-temperature object appears in the field of view of the camera monitoring the floor, it is determined that the high-temperature material has dropped, and an alarm signal is issued. Further, when a fire occurs, the shape of the high-temperature area changes rapidly, so that the occurrence of the fire is detected at this point. In this monitoring area, logic for recognizing the occurrence of a fire by observing the occurrence of a high-temperature area and a sudden change in shape is used.

(3) Grip firing monitoring logic (L3) of the robot arm: There is a case where oil adhering to the robot arm is ignited. In this case, the parallax when the heat-treated material moves within the visual field is detected. In this connection, the size of the high-temperature region gradually decreases as the heat-treated object moves away from the camera, and the size of the high-temperature region gradually increases when the heat treatment object approaches the camera. In such a state, when the robot arm ignites from the grip portion holding the heat-treated material, the area of the high-temperature portion sharply increases. Therefore, a fire is detected by this increase in the area.

(4) Logic for monitoring ignition from heating furnace door (L
4); If the door of the heating furnace is open, the inside of the high-temperature furnace or the leaked flame can be seen, and it is erroneously determined that a fire has occurred. In such a case, the shape of the high-temperature area indicated when the furnace door is opened is stored, and the open / close signal of the furnace door is input to the image processing apparatus, and the time during which the furnace door is open is specified in advance. If a high temperature area is detected after the furnace door is closed, logic is used to determine that a fire has occurred, as long as the fired shape is indicated.

FIG. 1 shows a system configuration diagram illustrating a fire detection device according to the present invention. FIG. 1 shows a case in which six color CCD cameras 10 are arranged, and the color CCD cameras 10 are sequentially switched every 0.2 seconds by a camera switcher 11 to monitor all the steps of the heat treatment. In this case, by connecting a video monitor in parallel with the camera switcher 11 and monitoring the monitoring area, the entire field of view can be monitored at 1.2 second intervals.

The color video signals sequentially sent from the six cameras are sent to the image processing device 12 and the color CCD camera 10
Is used as a confirmation signal of the monitoring position by the computer of the image processing apparatus 12. In this manner, the video signals sequentially transmitted from the six color CCD cameras can determine the occurrence of a fire by the logic corresponding to each of the monitoring areas described above. Outputs an alarm signal. In this system, Table 2 shows the relationship between the location of each color CCD camera, the object to be monitored, and the fire recognition logic described above.

[0026]

[Table 2]

Table 3 shows an example of the result of detecting a fire in the high-temperature heat treatment step by the above system and the fire recognition logic.

[0028]

[Table 3]

FIG. 3 illustrates a change in the shape of the high-temperature area when the floor is monitored by the camera number 3 and a fire occurrence is detected by the fire recognition logic L2. FIG. 3 shows the high temperature region by a long axis and a short axis, and shows the time change. It can be seen that both the long axis and the short axis sharply increase from the time of the fire occurrence.

[0030]

As described above, according to the fire detecting method and the fire detecting apparatus of the present invention, each pixel of the obtained image is monitored by a plurality of color CCD cameras for each predetermined visual field in the high-temperature heat treatment step. Is converted into chromaticity coordinates, only the chromaticity region designated in advance is extracted, and the occurrence of a fire is detected by recognizing the shape of the chromaticity coordinates and its change based on a fire recognition logic that differs for each monitoring image. Therefore, it is possible to quickly and accurately detect the occurrence of a fire without erroneously recognizing the light as a disturbance light such as a leakage flame from a heating furnace, lighting, or extraneous light. Therefore, it is extremely useful as a method and apparatus for detecting a fire in the step of industrially heat-treating a member such as a metal or ceramic.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram illustrating a fire detection device of the present invention.

FIG. 2 is a heat treatment process diagram schematically showing a process of transporting a heat-treated member.

FIG. 3 is a graph illustrating a relationship between a change in shape of a high-temperature region and an elapsed time when a fire occurrence is detected.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Heat processing thing 3 Door 4 1st robot 5 1st robot arm 6 Intermediate stage 7 2nd robot 8 2nd robot arm 9 Cooling stand 10 Color CCD camera 11 Camera switcher 12 Image processing device 13 Alarm device

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI G08B 21/00 G08B 21/00 AE H04N 7/18 H04N 7/18 N (72) Inventor Noboru Sasaki Toyota-cho, Toyota-shi, Aichi Prefecture 1st Toyota Motor Corporation (72) Inventor Motochika Nakamura 1st Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation

Claims (2)

[Claims] 1. A plurality of color CCD cameras sequentially monitor a predetermined visual field range in a high-temperature heat treatment process, convert each pixel of an obtained color image into chromaticity coordinates, and designate a pixel designated in advance from a monitored image. A fire detection method in a high-temperature heat treatment process, wherein only a chromaticity region is extracted and a shape or a change in shape of chromaticity coordinates is recognized by a fire recognition logic different for each monitoring image to detect a fire occurrence. 2. A plurality of color CCD cameras for monitoring a predetermined visual field range in a high-temperature heat treatment step, a camera switcher for switching a color image screen at predetermined time intervals, and converting each pixel of a color image into chromaticity coordinates. It consists of an image processing device that extracts only the chromaticity region to be monitored and detects the shape or shape change of the chromaticity coordinates according to the logic corresponding to the monitoring region, and an alarm device that detects a fire occurrence and outputs an alarm signal. A fire detection device in a high-temperature heat treatment step.