JPH0322936B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a water floc image recognition device that measures the particle size and distribution of floc in a floc formation pond (mixing pond) of a water treatment plant using image processing technology. .

[Background of the invention]

At water treatment plants, the suspended particles in the raw water are small in size, so the process is to agglomerate them into flocs, and then let the flocs settle. For this reason, it is essential to monitor the flocs in the floc formation pond (mixing pond).

Traditionally, flocs have been visually monitored several times a day by water treatment plant maintenance managers. Because it relies on visual inspection, the criteria for judgment are subjective and qualitative;
The drawback is that the monitoring results are not easily reflected in driving operations. Furthermore, since the monitoring frequency is discontinuous, countermeasures against agglomeration failures are delayed, which increases troubles.

In contrast, recently, a method has been adopted in which an industrial television camera (ITV) is used to monitor the flocs in the floc formation pond. However, even in this case, monitoring relies on human vision;
It remains subjective and discontinuous.

In order to improve these shortcomings, JP-A-54-
As described in No. 143296, a method has also been proposed in which a photoelectric conversion device is used to extract an electrical signal according to the shape of a flock. However, in practical use, there are problems such as illuminance and flow rate, and unless these problems are solved, it cannot be put into practical use.

[Purpose of the invention]

An object of the present invention is to provide a water floc image recognition device that can objectively and continuously measure the particle size and distribution of flocs in a floc formation pond (mixing basin) with high precision.

[Summary of the invention]

The inventors of the present invention conducted an experiment in which ITV images were image-processed, and found that it was not possible to recognize flock images at normal image processing speeds. In an experiment using an ultra-high-speed image processing device, that is, an image processing device that can recognize images of 512 x 480 pixels in 11 milliseconds (11 x 10 ^-3 seconds), it was possible to recognize images of flock groups with high accuracy. I couldn't do it. This is because the flocs are in a fluid state because the inside of the floc formation pond is agitated, and the flocs are moving. Since the moving speed of the flock is about 5 to 50 cm/sec, the distance the flock moves in 11 milliseconds (11 x 10 ^-3 seconds) is 0.55 to 5.5 mm. Since the grain size of the flocs is approximately 0.01 to 1.0 mm, it becomes impossible to recognize images of the flocs with high accuracy. In order to reduce the movement speed of the flocs, it is conceivable to provide a toothpick that blocks the streamlines of the water so that the movement speed of the flocs in the area to be observed is reduced. However, if you simply use a jiyama board,
If they are only placed in the surrounding area, the light from the illumination device will not hit the flocks, making it impossible to recognize images of the flocks stably and with high precision. In the present invention, a toothpick and an illumination device are arranged so that the light from the illumination device hits the flock group, so that images can be recognized with high precision.

[Embodiments of the Invention] Fig. 1 is a block diagram of a floc formation pond in a water treatment plant. In Figure 1, 10 is a floc formation pond, 1
1 is a stirring paddle, 12 is a floc, and 13 is a rectifying wall. A group of fine flocs that have flowed in from a rapid mixing pond (not shown) located before the floc formation pond 10 are stirred by the stirring paddle 11 in the floc formation pond 10, so that the flocs 12 collide with each other. aggregate. That is, the particle size of the floc increases. Normally, the floc formation pond 10 is composed of three ponds, each of which is partitioned by a rectifying wall 13. While Flotsu 12 passes through three ponds,
Gradually the particle size increases.

FIG. 2 shows an embodiment of the present invention for recognizing images of flocks in the flock formation pond 10.

In FIG. 2, 20 is an airtight container, 21 is an observation window, 22 is a wiper, 23 is a wiper drive device,
24 is a back screen, 24A and 24B are back screen fixtures, 25A, 25B, 25C
30 is an industrial television camera (ITV), 31 is a close-up lens, 40 is a lighting device,
32 is an ITV controller, 41 is a lighting device controller, 42 is a light shielding cover, 50 is an image recognition device, and 60 is an image recognition control device.

When the purpose of such a water floc image recognition device is to monitor the final degree of floc formation, it is placed upstream of the settling basin, that is, near the third outlet of the floc formation basin 10. In addition, when monitoring the process of floc formation, it is installed in the first or second of the floc formation ponds 10.

The configuration shown in FIG. 2 will be explained in more detail.

The ITV 30 fixed in the airtight container 20 uses a close-up lens 31 to enlarge and recognize an image of the flocs 12 in the floc formation pond 10 through an observation window 21 made of a transparent material such as glass. Wiper 22 driven by wiper drive device 23
is operated periodically to remove dirt from the surface of the observation window 21.

Further, the back screen 24 is installed as follows. In order to accurately recognize flock groups with high contrast, a back screen 24 is installed in front of the observation window 21 in the airtight container 20 via back screen fixtures 24A and 24B. Considering that the color of the flock 12 is white, the back screen 24 is desirably black in order to accurately recognize the flock with high contrast.

Next, the lighting device 40 and the light shielding cover 42 will be explained. The floc formation pond 10 is opened to the atmosphere for the purpose of constantly monitoring flocs. Therefore, the amount of light incident on the floc formation pond 10 changes over time and is strongly influenced by the weather. A lighting system 40 is usually installed to constantly monitor the flock. If the purpose is simply monitoring that depends on the eyesight of the maintenance manager, the lighting device 4
Needless to say, it is sufficient to install the lighting device 40 above the floc formation pond 10.

However, even if the illumination device 40 is installed, changes in ambient illuminance will strongly affect the accuracy of image recognition of the flock group. For example, if the illuminance is low, the flock will be perceived as small, and conversely, if the illuminance is high, the flock will be perceived as large. In order to eliminate this influence, it is necessary to avoid being influenced by changes in illuminance as a natural phenomenon.
In this embodiment, a light-shielding cover 42 is provided to darken the surroundings, and the illuminance is provided under a certain condition only by the illumination device 40. Note that if there is no light shielding cover 42,
Using the lighting device controller 41, the lighting conditions may be controlled in a timely manner according to changes in ambient illuminance. Furthermore, if circumstances permit, it is better to install a plurality of illumination devices 40 to irradiate the flock from multiple directions.

Next, issues regarding flock monitoring will be explained. As described above, since the inside of the floc formation pond 10 is stirred by the stirring paddle 11, the floc group is in a fluid state. The movement speed of flocs varies within the floc formation pond 10, but is between 5 and 50.
It is about cm/second. Therefore, it is necessary to perform image recognition of the flock group at high speed. But 512
In the case of ×480 pixels, even if a high-speed image recognition device is applied, it takes 11 milliseconds to recognize the pixels. Therefore, in order to accurately recognize images at the speed of current image recognition devices, it is necessary to reduce the moving speed of the flock group as much as possible.

Therefore, in the present invention, in order to suppress the movement of water as much as possible within the floc formation pond 10, a barrier board is arranged so as to block the movement direction of the water flow. However, in this case, if the shielding board were simply placed around the area where the flock group is observed, the light from the illumination device 40 would be blocked. Therefore, the wall board must be arranged so as to block the moving direction of the water flow, and must be configured so as not to block the light from the lighting device 40. At that time, the stirring paddle 11 is used in the floc formation pond 10.
Consider that the water is moving in a fixed direction due to stirring.

The arrangement of the wall board 25 and the lighting device 40 will be described below.

FIG. 3 is a perspective view of the main part of FIG. 2, showing the flow of water in the floc formation pond from the top to the bottom as shown by the white arrow A. and 25C are shown. The water flowing in from between the upper wall boards 25B and 25C, the back screen 24, and the airtight tank 20 flows into the back screen 24 and the airtight tank 20.
The water flows out from the gaps between the horizontal sides and the bottom board 25A. At this time, the jiyama boards 25B and 25
C is configured so as not to interfere with the light rays from the illumination device 40 and to allow the light rays to enter in a plane.

FIG. 4 shows a sectional view taken along line A-A' in FIG. However, the wiper 22 and wiper drive device 23 are not shown. The light that has passed between the jamb plates 25B and 25C and is incident in a planar manner irradiates a region 70 shown inside the dashed line. The region 70 is a planar space that extends in depth. This area 70
is inside the airtight tank 20 through the observation window 21.
The area 71 recognized by the ITV 30 and the close-up lens 31 is the target of image recognition. That is,
This area is common to the line (shown by a broken line) connecting the close-up lens 31 and the observation window 21 and the area 70 . This is a region 71 indicated by hatching. In this area 71 to be observed, the flow of water becomes gentle and the moving speed of the flock group becomes slow. Specifically, the moving speed of the flock group can be approximately 1 to 10 cm/sec. Since illumination is applied to these flocks on a flat surface, the flocks stand out due to the illumination and can be clearly recognized. on the other hand,
Areas other than area 71 (areas not subject to observation)
The illuminance is low because no light is emitted. Therefore, it is difficult to be recognized by the ITV 30 and the close-up lens 31. By arranging the barrier plate 25 in such a manner that it does not block the illumination light, the floc group in the floc formation pond 10 can be measured online with high accuracy.

With the above configuration, the flock image information captured by the ITV 30 is transmitted to the image recognition device 50 via the ITV controller 32. The image recognition device 50 performs various calculations on the characteristics of the flocs, such as particle size and distribution, in order to extract information useful for water quality management at the water purification plant from the obtained image information. Although the specific method is not described,
For example, a binarization process known as a known technique is performed to calculate the representative particle size of each floc in the floc group, and the particle size distribution of the floc group is determined.

10 to 12 show examples in which image recognition of flock groups is performed by performing binarization processing operations. 1st
Figure 0 is a diagram in which the floc group in the first pond of the floc formation pond 10 is recognized and binarized, and Figure 11 is a diagram in which the floc group in the second pond of the floc formation pond 10 is recognized and binarized. FIG. 12 is a diagram in which the floc group in the third pond of the floc formation pond 10 is recognized and binarized. From these figures, it can be seen that the floc particle size can be determined with high accuracy, and as a result, the growth process of the floc group can be clearly monitored on-line.

In the case of the floc formation pond 10, the water is stirred by the stirring paddle 11, so water containing new floc is constantly flowing in the area 71 in front of the ITV 30. Therefore, at regular time intervals,
Measurement accuracy can be improved by recognizing and capturing a floc image, performing this multiple times, and determining the floc particle size distribution based on this information.

The image recognition control device 60 controls the time sequence of the image recognition cycle at this time. That is,
The image recognition control device 60 is connected to the image recognition device 50 and
The recognition time and number of recognition times of flock image information by the ITV 30 are adjusted. Generally, the condition of floc formation does not change rapidly in a short period of time, so it is sufficient to monitor the floc formation by image recognition of the floc group once every minute to hour.

In addition, using the obtained particle size distribution, etc., the amount of coagulant injection, alkali agent injection amount, etc. can be controlled, and
It is possible to control the rotation speed of the stirring paddle.

FIG. 5 shows the main structure of another embodiment of the present invention. Fig. 5 is a mountain board 25A, 25B, 25C,
25D and 25E and the lighting device 40 are shown.

FIG. 5 shows a preferred embodiment where the water is moving laterally parallel to the back screen 24, as indicated by the white arrow B. The water flowing from the horizontal direction towards the cutting board 25D flows into the cutting board 25
It flows between the back screen 24 and the airtight tank 20 from between the back screen 24 and the airtight tank 20. This water cutting board 25A and cutting board 25
It flows out from between the back screen 24 and the airtight tank 20. Therefore, the area 71 to be observed
(not shown), the flow of water becomes slower.

FIG. 6 shows a main part configuration diagram of another embodiment of the present invention.

Figure 6 shows the wall plate 25 when the ITV 30 is placed across the wall 10A of the floc formation pond 10.
This shows the arrangement of A and 25B. Also,
Figure 7 shows the screen 24 and the binding boards 25A, 25.
It is a perspective view of B. 6 and 7 show the arrangement of the wall boards 25A and 25B and the illumination device 40 when water flows from the top to the bottom as indicated by the white arrow C.

FIG. 8 shows the main structure of another embodiment of the present invention.

Figure 8 shows lighting devices 40A and 40 on both sides.
This is an example in which illumination light is made uniform by installing B, 40C, and 40D. In order to pass the light of these lighting devices, the jamb boards 25C, 25D, 25E and 25F
Place.

Figure 9 is a sectional view taken along line B-B' in Figure 8.
5A and 25B are not shown). In this example, since two illumination devices are used to illuminate each side from both sides, the illuminance of the area 71 to be observed by the ITV 30 is made uniform. This has the effect of increasing the image recognition accuracy of the flock group.

〔Effect of the invention〕

According to the present invention, it is possible to reduce the movement speed of the flocs and uniformly illuminate these flocs, so that floc images in the water floc formation process can be objectively, quantitatively, and highly accurately viewed online. Can be measured automatically. This makes it possible to save labor and improve reliability in water treatment plant maintenance and management, and even to apply it to control systems.

[Brief explanation of drawings]

Figure 1 is a schematic configuration diagram of a floc formation pond in a water treatment plant, Figure 2 is a configuration diagram showing an embodiment of the present invention, and Figure 3
The figure is a perspective view of the main part of Figure 2, and Figure 4 is A- of Figure 3.
A′ sectional view, FIG. 5, and FIG. 6 are configuration diagrams of essential parts of other embodiments of the present invention, FIG. 7 is a perspective view of essential parts of FIG. 6, and FIG. 8 is another embodiment of the present invention. Main part configuration diagram of the example, FIG. 9 is a sectional view of FIG. 8, B-B' sectional view,
FIG. 12 is a diagram showing a binarized image obtained by implementing the present invention. 10...Floc formation pond, 11...Stirring paddle, 12...Floc, 20...Airtight container, 21
... Observation window, 24 ... Back screen, 25
A, 25B, 25C... each jiyama board, 30...
Industrial television camera (ITV), 40... lighting device, 42... light shielding cover, 50... image recognition device, 60... image recognition control device.

Claims (1)

[Claims] 1 Equipped with a lighting device that illuminates a group of flocs in a water treatment plant floc formation pond, captures image information of the floc group that receives light from the illumination device by a photoelectric conversion device, and processes the converted electric signal as an image. A water floc image recognition device, characterized in that a barrier plate is arranged to block the flow of flocs flowing into the area to be image processed and to allow the light of the illumination to pass through. recognition device.