JP2015169618A - visible smoke determination device and visible smoke determination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of objectively determining the presence of the generation of a visible smoke by quantitatively evaluating whether or not a smoke is the visible smoke.SOLUTION: A visible smoke determination device 1 includes: a camera 2 for imaging a smoke 12 discharged from a chimney 11; an image processing part 3 for generating a visible smoke determination image and setting a background region and a visible smoke determination region in the visible smoke determination image based on the image imaged by this camera 2; a calculation part 4 for calculating brightness for each color phase of the background region and the visible smoke determination region; and a determination part 5 for determining the smoke 12 imaged by the camera 2 as a visible smoke when a difference between the brightness of the background region and the brightness of the visible smoke determination region in each color phase calculated by the calculation part 4 is equal to or more than the preset threshold value in at least one color phase.

Description

  The present invention relates to a technique for determining whether smoke is visible smoke having visibility.

  Conventionally, in a steel mill, as described in Patent Document 1, exhaust gas discharged from equipment such as a coke oven and a sintering machine is processed into a product that satisfies a predetermined regulation value and a compliance value, and is emitted as smoke from a chimney. In addition to being discharged, it has been operated to suppress the generation of visible smoke from the viewpoint of voluntary environmental considerations and responding to the needs of residents near the factory. Therefore, whether or not visible smoke is generated from the chimney is constantly monitored by the monitoring center. If it is determined that visible smoke has been generated, the relevant equipment is promptly notified and the production volume is changed or the capacity of the electrostatic precipitator is changed so that visible smoke does not continue to be generated. As a result, operations will be adjusted. As described above, the determination of whether or not visible smoke is generated is handled as a very important matter in the operation of the steelworks.

Japanese Patent Laid-Open No. 08-005258

  However, at present, whether or not visible smoke has been generated is determined by human vision. Specifically, the smoke discharged from the chimney is imaged by the camera, and the captured smoke is displayed on the monitor screen of the monitoring center. Then, the operator of the monitoring center visually compares the monitor image with a reference photograph that is a reference for determining whether the smoke is visible. As a result of the comparison, for example, if the smoke color projected on the monitor screen is considered to be the same as or similar to the smoke color of the reference photograph, it is determined that visible smoke has been generated.

  In this way, in the operation of steelworks, whether or not the emitted smoke is visible smoke is determined using human vision, so the color of the smoke is qualitatively evaluated and the determination of visible smoke There are concerns that the objectivity of the standards is low. For this reason, there is also a problem that it is difficult to link the smoke determination result and the operation adjustment of the steelworks so that the operation of the steelworks is quickly adjusted according to the generation of visible smoke.

  The present invention has been made by paying attention to the above-described problems, and provides a technique capable of objectively determining whether or not the smoke is visible by quantitatively evaluating the smoke discharged from the chimney. Objective.

  An aspect of the visible smoke determination device according to the present invention is an image pickup device that picks up smoke emitted from a chimney, and generates a visible smoke determination image based on an image picked up by the image pickup device, and the visible smoke determination. An image processing unit that sets a background region and a visible smoke determination region in the image for use, a calculation unit that calculates brightness for each hue of the background region and the visible smoke determination region, and each of the calculation units calculated by the calculation unit A determination unit that determines that the smoke captured by the imaging device is visible smoke when the difference between the brightness of the background region in the hue and the brightness of the visible smoke determination region is equal to or greater than a preset threshold in at least one hue; The gist is to provide.

  An aspect of the visible smoke determination method according to the present invention includes a step of imaging smoke discharged from a chimney, a step of generating a visible smoke determination image based on the captured image, and the visible smoke determination image. A step of setting a background area and a visible smoke determination area, a step of calculating the brightness for each hue of the background area and the visible smoke determination area, and the brightness of the background area and the visible smoke in each calculated hue And a step of determining the imaged smoke as visible smoke when the difference from the brightness of the determination region is equal to or greater than a predetermined threshold in at least one hue of RGB.

  According to the present invention, since human vision is not used when evaluating the smoke discharged from the chimney, it is possible to objectively determine whether the smoke is visible smoke by quantitatively evaluating the smoke. it can.

It is a schematic block diagram explaining the structure of the visible smoke determination apparatus which concerns on embodiment of this invention. It is a schematic diagram of the image for visible smoke determination which concerns on embodiment of this invention. It is a schematic diagram of other embodiment of the image for visible smoke determination which concerns on this invention. FIG. 3 is a diagram showing smoke in the visible smoke determination image shown in FIG. 2. It is a flowchart explaining the visible smoke determination method which concerns on embodiment of this invention. It is a graph which shows the lightness in each hue when not visible with visible smoke for every flame | frame. It is a graph which shows the lightness in each hue in case of visible smoke generation | occurrence | production (II) for every flame | frame. It is a figure explaining the brightness difference of (I) when not visible with visible smoke in R phase, and the brightness difference of (II) when visible smoke is generated. It is a figure explaining the brightness difference of the case where it cannot visually recognize with visible smoke in G phase, and the brightness difference of (II) when visible smoke is generated. It is a figure explaining the brightness difference of the case (I) when not visible with visible smoke in B phase, and the brightness difference of (II) when visible smoke is generated.

  The visible smoke determination device according to the embodiment of the present invention is used for determining whether or not the smoke discharged from a sintering machine in an ironworks is visible smoke. The configuration will be described below with reference to the drawings. It should be noted that the shape, size, or ratio of each part shown in the drawing is appropriately simplified and exaggerated. Moreover, in the figure, the same code | symbol is attached | subjected to what has the same function, and the repeated description is abbreviate | omitted.

  As shown in FIG. 1, the visible smoke determination device 1 according to the present embodiment is connected to a camera 2 that is an imaging device that images the smoke 12 discharged from the chimney 11 of the sintering machine 10, and the camera 2. The image processing unit 3 includes a calculation unit 4 connected to the image processing unit 3, and a determination unit 5 connected to the calculation unit 4. The visible smoke determination device 1 includes a control unit 6 connected to the camera 2, the image processing unit 3, the calculation unit 4, and the determination unit 5, and a notification device 7 connected to the control unit 6.

The imaging of the smoke 12 by the camera 2 may be performed continuously so as to acquire one still image at a predetermined interval, for example, every 5 minutes, and the camera 2 is a moving image even if it is a camera that captures a still image. It may be a video camera for imaging. The interval for acquiring still images from the camera 2 is appropriately set via the control unit 6.
The image processing unit 3 generates a visible smoke determination image as shown in FIG. 2 based on an image captured by the camera 2 in a 256 gradation RGB color system. The image processing unit 3 sets a background area C0, a first visible smoke determination area A1, and a second visible smoke determination area A2 in the visible smoke determination image. The background area C0 and the first and second visible smoke determination areas A1 and A2 are areas used to determine whether or not the smoke 12 appearing in the visible smoke determination image is visible smoke.

  As shown in FIG. 2, in the present embodiment, one background region C0 is set in a horizontally long rectangular shape with a space from the chimney 11 on the left side of the upper portion of the chimney 11 when viewed from the front in FIG. 2. Further, the two visible smoke determination areas A1 and A2 are set in a square shape having the same size and spaced apart from each other above the background area C0. The position, shape, size, number, and the like of the background region C0 and the first and second visible smoke determination regions A1, A2 are appropriately set in the visible smoke determination image via the control unit 6. The background area C0 and the first and second visible smoke determination areas A1 and A2 can be set empirically based on the positions of visible smoke in images obtained by imaging visible smoke in the past.

  As another form example of the visible smoke determination image, there is a form shown in FIG. In FIG. 3, all of the five visible smoke determination areas A3 to A7 having the same dimensions are symmetrical with respect to the major axis of the chimney 11 so as to surround the chimney 11 with a space therebetween. Is set. In addition, square background areas C1 to C4 having the same size as the five visible smoke determination areas A3 to A7 are set at the four corners in the visible smoke determination image.

  By appropriately setting the position, shape, size, number, and the like of the background region C0, it is possible to flexibly set the background region C0 that is most suitable for calculating the brightness of the background according to the weather, wind direction, and the like on the shooting date. It becomes possible. Further, the position, shape, size, number, and the like of the first and second visible smoke determination areas A1, A2 can be set as appropriate, so that the most suitable visible smoke determination area for calculating the brightness of the smoke 12 can be flexibly selected. It becomes possible. In addition, in order to change the visible smoke determination area, it is not necessary to change the direction of the lens of the camera 2 one by one. Therefore, the operability of the visible smoke determination device 1 can be further improved.

  The calculation unit 4 calculates the brightness (R0, G0, B0) for each hue of RGB in the background area C0, and for each hue of RGB in the first and second visible smoke determination areas A1, A2. Brightness (R1, G1, B1) and (R2, G2, B2) are calculated. In the present embodiment, the lightness (R1, G1, B1) of the first visible smoke determination region A1 is set as the first lightness, and the lightness (R2, G2, B2) of the second visible smoke determination region A2 is set to the second lightness. Brightness.

  The brightness of each of the regions C0, A1, and A2 in this embodiment is, for example, when a certain rectangular region is composed of k (k = m × n) pixels having m rows and n columns. It is set as a weighted average value of the brightness of each hue of each pixel. That is, the lightness of the R phase of the entire region composed of k pixels is a value obtained by dividing the sum of the lightness of the R phase of each pixel by k. The same applies to the G phase and the B phase. The brightness of each area is not limited to the weighted average value, and other brightness such as a maximum value or an intermediate value in pixels included in the area may be set as appropriate.

  Further, the calculation unit 4 subtracts the first brightness (R1, G1, B1) from the brightness (R0, G0, B0) of the background area C0 for each hue, and the first brightness difference of the visible smoke determination area A1 in each hue. (ΔR1, ΔG1, ΔB1) are respectively calculated. Further, the calculation unit 4 subtracts the second brightness (R2, G2, B2) from the brightness (R0, G0, B0) of the background area C0 for each hue, and the second brightness difference of the visible smoke determination area A2 in each hue. (ΔR2, ΔG2, ΔB2) are respectively calculated.

  The calculated brightness (R0, G0, B0), first brightness (R1, G1, B1) and second brightness (R2, G2, B2) of the background region C0 in each hue are memories included in the visible smoke determination device 1 (Not shown) respectively. The calculated first lightness difference (ΔR1, ΔG1, ΔB1) and second lightness difference (ΔR2, ΔG2, ΔB2) in each hue are also stored in a memory (not shown).

The determination unit 5 is configured such that the first and second lightness differences (ΔR1, ΔG1, ΔB1) and (ΔR2, ΔG2, ΔB2) in the hues calculated by the calculation unit 4 are threshold values set in advance in at least one hue. At this time, the smoke 12 imaged by the camera 2 is determined as visible smoke.
In the present embodiment, the threshold is set to 10 in each of the RGB phases of the first visible smoke determination area A1. Also, in the second visible smoke determination area A2, as in the first visible smoke determination area A1, any threshold value of each RGB phase is set to 10. Each set threshold value is stored in the memory of the visible smoke determination device 1.

  Here, a threshold value setting method will be described. First, a plurality of visible smoke determination images are generated using the visible smoke determination device 1 according to the present embodiment, and lightness data of each RGB phase calculated from each visible smoke determination image is accumulated. Further, the operator visually recognizes the smoke in each visible smoke determination image to determine whether or not it is visible smoke. Based on the determination result, the visible smoke determination image determined to be visible smoke and the visible smoke determination image not determined to be visible smoke are classified. Then, the distribution of the brightness data of all the visible smoke determination images is analyzed, and the threshold value of each RGB phase for determining whether or not the visible smoke is present.

The threshold value may be the same value or a different value in each of the RGB phases. Further, a part or all of data such as date and time (season), weather, temperature, wind direction, etc. when the smoke 12 is imaged is accumulated in association with each visible smoke determination image, and a determination result of whether or not the smoke is visible And may be used for setting a threshold value.
The control unit 6 is used to appropriately change the function and parameters of each unit constituting the visible smoke determination device 1. For example, when image analysis software that executes the functions of the image processing unit 3, the calculation unit 4, and the determination unit 5 is installed in a personal computer (PC), the central processing unit (CPU) of the PC that executes the image analysis software controls the computer. This corresponds to part 6. The camera 2 can also be connected to a PC via the PC interface.

  For example, the control unit 6 changes settings such as an imaging interval and an imaging angle of the camera 2 and changes settings such as the position, shape, size, and number of visible smoke determination regions by the image processing unit 3. It is. Further, the control unit 6 outputs the brightness of each of the RGB phases in the regions C0, A1, and A2 calculated by the calculation unit 4 and the first and second brightness differences to an output device such as a display connected to the control unit 6 ( (Not shown). Moreover, the control part 6 outputs the signal which operates the alerting | reporting apparatus 7 based on the determination result whether the smoke 12 of the image for visible smoke determination is visible smoke.

  When the determination unit 5 determines that the smoke 12 captured by the camera 2 is visible smoke, the notification device 7 performs an operation of notifying the operator of the monitoring center of the occurrence of visible smoke. The notification operation may be, for example, a configuration in which characters indicating the occurrence of visible smoke are output on the display screen of the PC, or a configuration in which an alarm or warning light that calls attention is operated.

Next, operation | movement of the visible smoke determination apparatus 1 which concerns on this embodiment is demonstrated with reference to FIG.
First, as shown in FIG. 5, the camera 2 of the visible smoke determination device 1 images the smoke 12 discharged from the chimney 11 of the sintering machine 10 (S10). As a result of imaging, a still image including the upper part of the chimney 11 is transmitted to the image processing unit 3 at a predetermined interval.
Next, the image processing unit 3 generates a visible smoke determination image based on the captured still image (S11).

  Next, the image processing unit 3 sets the background area C0 and the first and visible smoke determination areas A1 and A2 in the generated visible smoke determination image (S12). The visible smoke determination image of the determination method according to the present embodiment is the visible smoke determination image shown in FIG. 4. The smoke 12 does not overlap the background region C0 and only the background sky appears. In the first visible smoke determination area A1, smoke 12 appears to overlap with the exception of a part of the lower left corner in FIG. Further, in the second visible smoke determination area A2, smoke 12 appears over the entire area.

Next, the calculation unit 4 calculates the lightness (R0, G0, B0) of the background region C0 (S13). Also, the first brightness (R1, G1, B1) and the second brightness (R2, G2, B2) are calculated (S14). Further, the first lightness difference (ΔR1, ΔG1, ΔB1) and the second lightness difference (ΔR2, ΔG2, ΔB2) are calculated (S15).
Next, the determination unit 5 determines, for each hue, the threshold value stored in the memory and the calculated first lightness difference (ΔR1, ΔG1, ΔB1) and second lightness difference (ΔR2, ΔG2, ΔB2), respectively. Compare.

  First, the comparison process in the R phase will be described. The first brightness difference R-phase value ΔR1 and the second brightness difference R-phase value ΔR2 are respectively compared with the R-phase threshold value. If either one of the first brightness difference R-phase value ΔR1 and the second brightness difference R-phase value ΔR2 is equal to or greater than the threshold value, the smoke 12 imaged by the camera 2, that is, the chimney 11 of the sintering machine 10 is used. The smoke 12 discharged from the air is determined as visible smoke (S19). In this case, each brightness difference in the subsequent G phase and B phase may be compared with the threshold value, or may not be performed. On the other hand, when both the R-phase value ΔR1 of the first brightness difference and the R-phase value ΔR2 of the second brightness difference are less than the R-phase threshold value, the process proceeds to the comparison process in the G-phase indicated by S17 in FIG. (S16).

  Next, the comparison process in the G phase will be described. The G-phase value ΔG1 of the first brightness difference and the G-phase value ΔG2 of the second brightness difference are respectively compared with the G-phase threshold value. When either one of the G-phase value ΔG1 of the first brightness difference and the G-phase value ΔG2 of the second brightness difference is equal to or greater than the threshold value, the smoke 12 captured by the camera 2, that is, the chimney 11 of the sintering machine 10 is used. The smoke 12 discharged from the air is determined as visible smoke (S19). In this case, the comparison between each brightness difference and the threshold value in the subsequent B phase may or may not be performed. On the other hand, if both the first brightness difference G-phase value ΔG1 and the second brightness difference G-phase value ΔG2 are less than the G-phase threshold value, the process proceeds to the comparison process in the B-phase indicated by S18 in FIG. (S17).

  Finally, the comparison process in the B phase will be described. The first lightness difference B-phase value ΔB1 and the second lightness difference B-phase value ΔB2 are respectively compared with the B-phase threshold. When either one of the first brightness difference B-phase value ΔB1 and the second brightness difference B-phase value ΔB2 is equal to or greater than the threshold value, the smoke 12 imaged by the camera 2, that is, the chimney 11 of the sintering machine 10 is used. The smoke 12 discharged from the air is determined as visible smoke (S19). On the other hand, when both of the first brightness difference B-phase value ΔB1 and the second brightness difference B-phase value ΔB2 are less than the B-phase threshold, the visible smoke determination processing in the visible smoke determination image is terminated. (S18).

  That is, as a result of the comparison process in each of the RGB phases, all six brightness differences including the three values ΔR1, ΔG1, ΔB1 of the first brightness difference and the three values ΔR2, ΔG2, ΔB2 of the second brightness difference are obtained. However, when the values are less than the set threshold values, the smoke 12 in the visible smoke determination image is not determined to be visible smoke. Then, the visible smoke determination process for the visible smoke determination image ends, and the series of processes (S10 to S19) described above are repeated for the subsequent visible smoke determination image.

  On the other hand, as a result of the comparison processing in each of the RGB phases, at least of the six brightness differences including the three values ΔR1, ΔG1, ΔB1 of the first brightness difference and the three values ΔR2, ΔG2, ΔB2 of the second brightness difference. When one brightness difference is equal to or greater than a threshold value set in the hue of the visible smoke determination region, the smoke 12 in the visible smoke determination image is determined as visible smoke. For example, even if two R-phase brightness differences ΔR1 and ΔR2 are both less than the R-phase threshold, at least one of the two G-phase brightness differences ΔG1 and ΔG2 is greater than or equal to the G threshold. If it is, it will be determined that it is visible smoke.

  When it is determined that the smoke 12 is visible smoke, the notification device 7 notifies the operator of the monitoring center that the visible smoke has been generated, together with data such as the imaging time of the visible smoke determination image (S20). The operator of the monitoring center notifies the person in charge of the sintering machine 10 of the chimney 11 where visible smoke is generated by telephone or the like about the occurrence of visible smoke. The administrator of the sintering machine 10 that has been contacted confirms the carbon content concentration in the sintered material supplied to the sintering machine 10 and the dust collection status of the electric dust collector so that visible smoke does not continue to be generated. The operation will be adjusted accordingly. The visible smoke determination method according to the present embodiment is configured as described above.

In addition, when the notification process (S20) is performed once, the person in charge of the sintering machine 10 is not immediately contacted, but the notification process is performed a plurality of times, for example, when the alarm is continuously notified three times, It is preferable for the following reasons that the person in charge of the sintering machine 10 is contacted.
When the smoke 12 is imaged by the camera 2, an unintended flying object such as a bird is projected on the imaging screen and may appear overlapping the visible smoke determination area in the visible smoke determination image. In that case, there is a concern that the brightness of the background area CO and the brightness of the visible smoke determination area reflecting the color of the flying object are compared and erroneously determined as visible smoke. Therefore, when the visible smoke determination method according to the present embodiment is linked with the operation of the sintering machine 10, the operation of the sintering machine 10 is adjusted when the notification process is executed a predetermined number of times. If comprised in this way, the misjudgment of visible smoke can be suppressed and operation can be performed effectively.

In addition, after the notification process (S20), the form of communication performed to the target equipment to adjust the operation is not limited to the manual operation by the operator of the monitoring center, but automatically with the execution of the notification process (S20). You may comprise so that contact may be made.
In the present embodiment, two visible smoke determination areas are set, and if the lightness difference ΔG1, ΔG2 of any one of the two visible smoke determination areas A1, A2 is equal to or greater than a threshold value, It is determined that visible smoke has been generated. In this way, it is determined that visible smoke has occurred when a plurality of visible smoke determination areas are provided and at least one of the brightness differences is equal to or greater than a preset threshold value. Therefore, even when a certain visible smoke determination area and the smoke 12 do not appear to overlap each other, it is possible to suppress missing the visible smoke by complementing the determination with another visible smoke determination area.

Next, the Example performed using the visible smoke determination apparatus 1 which concerns on this embodiment is described using FIGS.
First, a commercially available digital video camera capable of capturing a moving image is prepared as the camera 2, fixed at a predetermined position where the smoke 11 of the chimney 10 can be imaged, and the visible smoke determination device 1 is set so that the smoke 11 can be continuously captured. Configured. Further, this digital video camera is connected to a PC in a monitoring room in which image analysis software is installed, and a moving image transmitted from the digital video camera is displayed on the display of the PC. Also, it is configured to obtain a 256-gradation RGB color system still image as a visible smoke determination image of 1 frame (100 frames for 2 minutes and 30 seconds) at 1.5 second intervals from the transmitted moving image. did.

As shown in FIG. 2, the background smoke C0 and the first and second visible smoke judgment areas A1 and A2 are set in the visible smoke judgment image, and each of the RGB phases of the first visible smoke judgment area A1 is set. The thresholds were all set to 10. In addition, the threshold values of the respective RGB phases of the second visible smoke determination area A2 were all set to 10.
Next, imaging of the chimney 11 of the sintering machine 10 was started using the visible smoke determination device 1. FIG. 6 shows changes in the brightness of each RGB phase when smoke 12 cannot be visually recognized as visible smoke by an operator in a certain time zone during imaging. In addition, about one hour after the occurrence of the case of (I), when the visible smoke having a brownish color is visually recognized by the operator and determined to be visible smoke, the change in the brightness of each RGB phase in (II) Is shown in FIG. In both cases (I) and (II), the weather at the time of imaging was cloudy. In addition, a white cloud appeared in the entire background region C0 set in the visible smoke determination image.

  As shown in FIG. 6, when visible smoke is not visible (I), in the R phase, the brightness R0 of the background area C0, the brightness R1 of the first visible smoke determination area, and the brightness R2 of the second visible smoke determination area. Each of the values was around 125, and a tendency to show almost the same value over 100 frames (2 minutes 30 seconds) was shown. Also, the R value ΔR1 of the first brightness difference and the R phase value ΔR2 of the second brightness difference were almost the same value, indicating a tendency not to vary greatly.

  In the G phase, the lightness R0 of the background region C0, the lightness G1 of the first visible smoke determination region, and the lightness G2 of the second visible smoke determination region all have values between 140 and 145, and R Similar to the phase, there was a tendency to show approximately the same value over 100 frames (2 minutes 30 seconds). Further, the G value ΔG1 of the first lightness difference and the G phase value ΔG2 of the second lightness difference showed substantially the same value, indicating a tendency not to vary greatly.

  In the phase B, the brightness B0 of the background area C0, the brightness B1 of the first visible smoke determination area, and the brightness B2 of the second visible smoke determination area all have values between 150 and 155, and 100 There was a tendency to show approximately the same value over the frame (2 minutes 30 seconds). Also, the B value ΔB1 of the first lightness difference and the B phase value ΔB2 of the second lightness difference were almost the same value, indicating a tendency not to vary greatly.

Next, FIG. 8 shows average values of 100 frame values of the R-phase brightness R0 to R2 shown in FIGS. 6 and 7 separately for the cases (I) and (II). Similarly, FIG. 9 shows an average value of 100 frames of G phase brightness G0 to G2, and FIG. 10 shows an average of 100 frames of B phase brightness B0 to B2.
First, the R phase will be described. As shown in FIG. 8, in the case of (I) that cannot be visually recognized as visible smoke, the average value of the R phase brightness R0 of the background region C0 is about 126, and the average value of the first and second brightness R1, R2 is In all cases, the value was about 124. The R value ΔR1 of the first lightness difference and the R phase value ΔR2 of the second lightness difference were both about the same value of 2.

On the other hand, in the case of (II) where visible smoke is generated, the average value of the R phase brightness R0 of the background region C0 is about 125, and the average values of the first and second brightness R1, R2 are both about 121. Value. The first lightness difference R-phase value ΔR1 and the second lightness difference R-phase value ΔR2 are both about 4, which is larger than the case of (I) where visible smoke is not visible.
Next, the G phase will be described. As shown in FIG. 8, in the case of (I) that cannot be visually recognized as visible smoke, the average value of the G phase lightness G0 in the background region is a value of about 144, and the average values of the first and second lightness values G1 and G2 are respectively The value was about 143,142. The first brightness difference G-phase value ΔG1 and the second brightness difference G-phase value ΔG2 were about 1 and 2, respectively.

On the other hand, in the case of (II) where visible smoke is generated, the average value of the G-phase lightness G0 in the background region is about 144, and the average values of the first and second lightness G1 and G2 are about 135 and 133, respectively. Value. The first brightness difference G-phase value ΔG1 and the second brightness difference G-phase value ΔG2 were values of about 9 and 11, respectively, which were larger than in the case of (I) where no visible smoke was visible.
Finally, the B phase will be described. As shown in FIG. 10, in the case of (I) that cannot be visually recognized as visible smoke, the average value of the B phase lightness B0 in the background region is about 144, and the average values of the first and second lightness values B1 and B2 are respectively The value was about 143,142. The first lightness difference B-phase value ΔB1 and the second lightness difference B-phase value ΔB2 were about 1 and 2, respectively.

On the other hand, in the case of (II) where visible smoke is generated, the average value of the B phase lightness B0 in the background region is about 144, and the average values of the first and second lightness B1 and B2 are about 135 and 133, respectively. Value. The first lightness difference B-phase value ΔB1 and the second lightness difference B-phase value ΔB2 were values of about 9 and 11, respectively, which were larger than in the case of (I) where no visible smoke was visible.
In this example, in any of the RGB hues, the first and second brightness differences were larger in the case of (II) where visible smoke was generated than in the case of (I) where visible smoke was not visible. Among them, the G-phase value ΔG2 of the second brightness difference and the B-phase value ΔB2 of the second brightness difference were both 11 and exceeded the threshold value of 10. And the smoke 12 imaged by the camera 2 was determined to be visible smoke by the visible smoke determination device 1. And the determination result of the visible smoke determination apparatus 1 became the same as the determination result by an operator's visual recognition.
(effect)
According to the visible smoke determination device 1 according to the present embodiment, each brightness difference (ΔR1, ΔG1, ΔB1) between the background region C0 and the first and second visible smoke determination regions A1, A2 in each RGB phase ( ΔR2, ΔG2, ΔB2) are used to quantitatively evaluate the smoke 12 discharged from the chimney 11. Therefore, since human vision is not used when evaluating the smoke 12, it is possible to objectively determine whether the smoke 12 is visible smoke by quantitatively evaluating the smoke 12 discharged from the chimney 11. it can.

  Further, in the present embodiment, absolute value comparison for comparing the first lightness (R1, G1, B1) and the second lightness (R2, G2, B2) with a predetermined threshold value is not performed. After calculating the lightness (R0, G0, B0) of the background region C0, the first lightness difference (ΔR1, ΔG1, ΔB1) that is the difference between the lightness of the background region C0 and the first lightness, and the background region C0 A relative value comparison is performed in which the second lightness difference (ΔR2, ΔG2, ΔB2), which is the difference between the lightness and the second lightness, is compared with a predetermined threshold value. This is because, for example, when there are many blackish clouds in the background on a certain imaging date, when these clouds appear in the first or second visible smoke determination areas A1 and A2, the visible smoke determination device 1 This is to prevent the cloud from being erroneously determined to be visible smoke. In this regard, in the present embodiment, visible smoke is generated from the case where the first lightness difference (ΔR1, ΔG1, ΔB1) and the second lightness difference (ΔR2, ΔG2, ΔB2) are invisible to visible smoke (I) ( Focusing on the fact that the case of II) is enlarged, a relative value comparison is performed. Therefore, erroneous determination can be reduced and the accuracy of visible smoke determination can be further improved.

  In the present embodiment, the lightness difference between the lightness values of the background region and the visible smoke determination region is used to determine whether the smoke is visible smoke, but the present invention is limited to this. It is not a thing. For example, it is good also as a structure which determines using the ratio of the brightness of the area | region for visible smoke determination with respect to the brightness of a background area | region. In this case, for example, the calculation unit 4 in the present embodiment is configured to calculate the ratio of the lightness of the visible smoke determination region to the lightness of the background region, and the determination unit 4 is preset with the calculated ratio. The smoke 12 imaged by the camera 2 is determined to be visible smoke as compared to the threshold value.

  At this time, as in the above-described embodiment, in the case of (II) in which visible smoke is generated, the lightness of the visible smoke determination region with respect to the lightness of the background region is higher than in the case of (I) in which visible smoke is not visible. The ratio increases. For example, in the B phase of the embodiment (see FIG. 10), the ratio of the first brightness B1 to the brightness B0 of the background region is about 1.007 in the case of (I) and about 1.077 in the case of (II). It is. Therefore, when the ratio of the first lightness B1 to the lightness B0 of the background region is equal to or higher than a preset threshold value, the smoke 12 may be determined to be visible smoke. In short, it may be configured to perform a relative value comparison based on the brightness of the background area and the brightness of the visible smoke determination area.

The imaging device according to the present invention may be any device that can obtain a still image that can be used as a visible smoke determination image at a predetermined interval, and may be a video camera for moving image capturing or a camera for still image capturing. Good.
The color specification format of the visible smoke determination image according to the present invention is not limited to the RGB system, and may be another color system such as an RGBA system or a YCbCr system. The lightness gradation is not limited to 256 gradations, and may be other gradations such as 0 to 1.

  In addition, the visible smoke determination device and the visible smoke determination method according to the present invention are not limited to use in steelworks, and determine whether smoke discharged from other various factories and smoke exhaust facilities is visible smoke. May be used in some cases.

DESCRIPTION OF SYMBOLS 1 ... Visible smoke determination apparatus 2 ... Camera 3 ... Image processing part 4 ... Calculation part 5 ... Determination part 6 ... Control part 7 ... Notification apparatus 10 ... Sintering machine 11 ... Chimney 12 ... Smoke A1 ... Area for 1st visible smoke determination A2 ... second visible smoke determination area C0 ... background area

Claims (7)

An imaging device for imaging smoke discharged from the chimney;
An image processing unit that generates a visible smoke determination image based on an image captured by the imaging device and sets a background region and a visible smoke determination region in the visible smoke determination image;
A calculation unit for calculating brightness for each hue of the background region and the visible smoke determination region;
When the difference between the lightness of the background region and the lightness of the visible smoke determination region in each hue calculated by the calculation unit is equal to or larger than a preset threshold value in at least one hue, the image is captured by the imaging device. A determination unit for determining the smoke as visible smoke,
Visible smoke judging device.   The visible smoke determination device according to claim 1, wherein the visible smoke determination image is an image of an RGB color system with 256 gradations.   The visible smoke determination device according to claim 2, wherein the threshold value is 10.   The visible device according to any one of claims 1 to 3, further comprising a notification device that notifies generation of visible smoke when the smoke discharged from the chimney is determined to be visible smoke by the determination unit. Smoke detector.   The visible smoke judging device according to any one of claims 1 to 4, wherein the smoke is smoke discharged from an exhaust gas chimney of a sintering machine at an ironworks. Imaging smoke emitted from the chimney;
Generating a visible smoke determination image based on the captured image;
Setting a background area and a visible smoke determination area in the visible smoke determination image;
Calculating brightness for each hue of the background region and the visible smoke determination region;
When the difference between the calculated brightness of the background area and the brightness of the visible smoke determination area in each hue is equal to or greater than a preset threshold value in at least one of the hues of RGB, the captured smoke is changed to visible smoke. A step of determining
A method for determining visible smoke, comprising:   The visible smoke determination method according to claim 6, wherein the visible smoke determination image is an image of a 256-color RGB color system.

Images