JP7685638B2 - Floating object observation device - Google Patents

Description

The present invention relates to a floating object observation device that captures floating objects such as flocs in a liquid.

Conventionally, as shown in FIG. 14, this type of floating object observation device is configured to irradiate a sheet laser beam 103 from the outside of a stirring tank 102 that stores raw water 101, and to photograph the area of the raw water 101 in the stirring tank 102 that is irradiated with the sheet laser beam 103 from outside the stirring tank 102.

Here, the mixing tank 102 has an entrance area where the sheet laser light 103 enters and a viewing area where imaging is performed, each of which is configured with a transparent glass window (not shown). The sheet laser light 103 is irradiated in a fan-like manner from an irradiation unit 104 provided outside the mixing tank 102. Also, provided outside the mixing tank 102 is an imaging unit 105 that images the irradiation area in the mixing tank 102 irradiated with the sheet laser light 103 to generate a captured image.

According to this, by photographing the irradiated area in the mixing tank 102 with the photographing unit 105, it is possible to obtain a photographed image of the flocs in the raw water 101 in the irradiated area irradiated with the sheet laser light 103. By binarizing this photographed image, it is possible to measure the shape, size, number, etc. of the flocs.

The above-mentioned floating object observation device is described, for example, in Patent Document 1 below.

Patent Publication No. 2018-4506

However, in the above conventional method, it is necessary to provide the mixing tank 102 with an entrance glass window that allows the sheet laser light 103 to enter the mixing tank 102 from the outside to the inside, and an imaging glass window that allows the inside of the mixing tank 102 to be imaged from the outside. If such glass windows become dirty, there is a risk that the accuracy of the captured image will decrease, so the glass windows must be cleaned frequently, resulting in problems such as time-consuming maintenance.

The present invention aims to provide a floating object observation device that can reduce the maintenance effort and obtain clear images of floating objects.

In order to achieve the above object, the first invention is a floating matter observation device for observing floating matters in a liquid, comprising:
A laser light source that irradiates the liquid surface with a sheet laser light that spreads laterally, and an imaging device that images a floating object irradiated with the sheet laser light incident from the liquid surface are provided above the liquid surface,
The point where the sheet laser light is incident on the liquid surface from above the liquid surface is defined as the liquid surface incident point.
If the location where the reflected light that is incident on the imaging device passes through the liquid surface among the reflected light of the sheet laser light that hits the floating object is defined as the liquid surface passing location,
A wave breaker is provided to surround the liquid surface incident point and the liquid surface passing point above and below the liquid surface to block waves on the liquid surface;
an imaging range for imaging the floating object irradiated with the sheet laser light by an imaging device is set below the liquid surface;
The laser light source and the imaging device are arranged so that the traveling path of the sheet laser light and the traveling path of the reflected light are perpendicular to each other in the imaging range.

As a result, since the laser light source and imaging device are located above the liquid surface, there is no need to provide an entrance glass window or an imaging glass window in the tank, making maintenance easy and reducing the amount of maintenance work required.

In addition, the wave-breaking member surrounds the liquid surface entry point and the liquid surface passage point above and below the liquid surface, blocking waves on the liquid surface, preventing the sheet laser light and reflected light from being affected by the waves on the liquid surface and fluctuating irregularly in the liquid. This prevents the captured image from being distorted, allowing clear images of floating objects to be obtained.

It also reduces focus deviations within the imaging range, allowing for clear, in-focus images of floating objects to be obtained.

The floating object observation device in the second invention has a light-shielding member provided between the laser light source and the imaging device to prevent the sheet laser light irradiated from the laser light source and reflected by the liquid surface from entering the imaging device.

As a result, the light-shielding member blocks the sheet laser light irradiated from the laser light source and reflected by the liquid surface, preventing the sheet laser light reflected by the liquid surface from entering the imaging device, thereby enabling a clear image of the floating matter to be obtained.

In the floating object observation device according to the third invention, an opaque case that houses a laser light source and an imaging device also serves as a wave breaker,
The liquid level incidence point and the liquid level passing point are inside the case,
A lower end opening that opens below the liquid surface is formed at the lower end of the case,
The sheet laser light passes through the bottom opening from inside the case and reaches the imaging range.
The reflected light passes from the imaging range through the lower opening and enters the case.

As a result, the case surrounds the point where the light enters the liquid surface and the point where the light passes through the liquid surface, blocking waves on the liquid surface, preventing the sheet laser light and reflected light from being affected by waves on the liquid surface and fluctuating irregularly in the liquid.

In addition, when the floating object observation device is installed outdoors, the case blocks sunlight, preventing it from entering the imaging device and allowing clear images of floating objects to be obtained.

In the floating matter observation device of the fourth invention, the floating matter is flocs produced by adding a flocculant to the liquid.

This allows clearer images of flocs to be obtained, improving the accuracy of floc observation.

As described above, the present invention makes it possible to reduce the maintenance effort and obtain clear images of floating objects. It also improves the accuracy of observing floating objects.

1 is a cross-sectional view of a floating object observation device in a first embodiment of the present invention. FIG. This is a basic conceptual diagram showing in three dimensions the main components of the floating object observation device. FIG. 4 is a cross-sectional view of a floating object observation device in a second embodiment of the present invention. FIG. FIG. 11 is a cross-sectional view of a floating object observation device in a third embodiment of the present invention. FIG. 2 is a partially cutaway bottom view of the floating object observation device according to the first embodiment. FIG. 13 is a cross-sectional view of a floating object observation device in a fourth embodiment of the present invention. FIG. 2 is a partially cutaway bottom view of the floating object observation device according to the first embodiment. FIG. 13 is a cross-sectional view of a floating object observation device in a fifth embodiment of the present invention. FIG. 2 is a partially cutaway bottom view of the floating object observation device according to the first embodiment. FIG. 13 is a cross-sectional view of a floating object observation device in a sixth embodiment of the present invention. 13 is a view taken along the line XX in FIG. 12. FIG. 1 is a diagram of a conventional floating object observation device.

The following describes an embodiment of the present invention with reference to the drawings.

(First embodiment)
In the first embodiment, as shown in Fig. 1, reference numeral 1 denotes a flocculation tank installed in, for example, a water purification plant. Raw water 2 (an example of a liquid) is stored in the flocculation tank 1, and a large number of flocs 3 (an example of suspended matter) are generated in the raw water 2 by adding a coagulant to the raw water 2.

As shown in Figures 1 to 3, the flocculation tank 1 is provided with a floating matter observation device 10 that observes flocs 3 in the raw water 2. The floating matter observation device 10 has a laser light source 12 that irradiates the water surface 4 (liquid surface) with sheet laser light 11, and a camera 14 (an example of an imaging device) that images the flocs 3 irradiated with the sheet laser light 11 incident from the water surface 4.

The sheet laser light 11 spreads out laterally from the laser light source 12 in a fan shape when viewed from above as shown in FIG. 2, and is approximately linear when viewed from the side as shown in FIG. 1.

The laser light source 12 and camera 14 are installed above the water surface 4 and are supported by a fixed frame (not shown) fixed to the tank wall 1a of the flocculation tank 1.

The point where the sheet laser light 11 enters the water surface 4 from above the water surface 4 is referred to as the water surface entrance point 16 (liquid surface entrance point). Also, the point where the reflected light 17 that is reflected by the sheet laser light 11 hitting the flocks 3 and enters the lens 15 of the camera 14 passes through the water surface 4 from bottom to top is referred to as the water surface passing point 18 (liquid surface passing point).

A wave breaker 20 is provided to surround the water surface incidence point 16 and the water surface passage point 18 and block waves on the water surface 4. The wave breaker 20 is a cylindrical member supported by a fixed frame (not shown) fixed to the tank wall 1a or bottom of the flocculation tank 1, with its lower end submerged below the water surface 4 and its upper end protruding above the water surface 4.

The imaging range 21 in which the camera 14 images the flocks 3 irradiated with the sheet laser light 11 is set in an area below the water surface 4 below the lower end of the wave breaker 20. The laser light source 12 and the camera 14 are disposed at a position where the travel path 23 of the sheet laser light 11 and the travel path 24 of the reflected light 17 intersect at right angles in the imaging range 21. When disposed in this manner, the incidence angle A1 of the sheet laser light 11 is 54° and the refraction angle A2 is 37°. The incidence angle B1 of the reflected light 17 is 37° and the refraction angle B2 is 54°. The values of the incidence angles A1, B1 and the refraction angles A2, B2 are merely examples and vary depending on the properties of the raw water 2 (e.g., specific gravity, etc.).

In addition, in FIG. 1, for convenience, the size of the flocculation tank 1 is drawn to be approximately one size larger than the floating matter observation device 10, but in reality, the size of the flocculation tank 1 is significantly larger than the floating matter observation device 10.

The operation of the above configuration will be described below.
A sheet laser light 11 is irradiated from a laser light source 12, and the flocs 3 within an imaging range 21 are imaged by a camera 14. At this time, the wave breaker 20 surrounds the water surface incidence point 16 and the water surface passing point 18 above and below the water surface 4 to block the waves on the water surface 4, so that the sheet laser light 11 and the reflected light 17 can be prevented from irregularly swaying in the raw water 2 due to the influence of the waves on the water surface 4. This makes it possible to prevent the captured image from being distorted, and a clear image of the flocs 3 can be obtained.

In addition, since the imaging range 21 is set in an area below the lower end of the wave breaker 20, even if it is difficult for the flocks 3 to flow inside the wave breaker 20, the camera 14 can reliably image the flocks 3 in the area below the wave breaker 20, improving the observation accuracy of the flocks 3.

In addition, since the travel path 23 of the sheet laser light 11 and the travel path 24 of the reflected light 17 are perpendicular to each other in the imaging range 21, it is possible to reduce the focus shift in the imaging range 21, and it is possible to obtain a clear, in-focus image of the flocks 3. By subjecting the image obtained in this manner to a binarization process, it is possible to accurately measure the shape, size, number, etc. of the flocks 3, and the observation accuracy of the flocks 3 is improved.

In addition, since the laser light source 12 and the camera 14 are installed above the water surface 4, there is no need to install an entrance glass window or a photographing glass window in the flocculation tank 1, which makes maintenance easy and reduces the maintenance effort.

In addition, since the laser light source 12 and the camera 14 do not come into contact with the raw water 2, it is possible to prevent the laser light source 12 and the camera 14 from becoming dirty or breaking down, compared to when the laser light source 12 and the camera 14 are installed underwater.

Second Embodiment
4 and 5, in the second embodiment, a part 11a of the sheet laser light 11 irradiated from the laser light source 12 may be reflected by the water surface 4. A light shielding member 30 that prevents the part of the sheet laser light 11a reflected by the water surface 4 from entering the camera 14 is provided on the water surface 4 between the laser light source 12 and the camera 14. The light shielding member 30 is a flat, opaque member and is attached to the wave breaker member 20.

As a result, the light blocking member 30 blocks the sheet laser light 11a reflected by the water surface 4, thereby preventing the sheet laser light 11a reflected by the water surface 4 from entering the camera 14. This makes it possible to obtain a clear image of the flock 3.

In the first and second embodiments described above, as shown in Figures 1 and 4, the imaging range 21 is set in an area below the lower end of the wave breaker member 20, but the upper part of the imaging range 21 may be slightly above the lower end of the wave breaker member 20.

In the first and second embodiments described above, the wave breaker member 20 is formed in a cylindrical shape as shown in Figures 2 and 5, but it may also be formed in a rectangular tube shape.

Third Embodiment
In the third embodiment, as shown in Figures 6 and 7, the laser light source 12 and the camera 14 are housed in an opaque case 35. The case 35 also functions as a wave breaker 20, and has one case body 35a and the other case body 35b connected in a V shape in side view. The lower part of the case 35 is submerged below the water surface 4, and the upper part of the case 35 protrudes above the water surface 4.

Both case bodies 35a, 35b are each a rectangular cylinder with a closed upper end, and have an upper plate 60, a lower plate 61, a pair of side plates 62, and an upper end cover plate 63. The lower ends of both case bodies 35a, 35b are connected to each other. In addition, a lower end opening 36 that opens below the water surface 4 is formed at the lower end of the case 35.

The laser light source 12 is provided in one case body 35a, the camera 14 is provided in the other case body 35b, and the lower end opening 36 is connected to both case bodies 35a, 35b. In addition, the water surface incidence point 16 is in one case body 35a, and the water surface passing point 18 is in the other case body 35b. Furthermore, the imaging range 21 is set in the area below the lower end opening 36.

Note that the horizontal distance between the laser light source 12 and the camera 14 at this time is C1, and the imaging depth from the water surface 4 to the imaging range 21 is D1.

The operation of the above configuration will be described below.
The sheet laser light 11 irradiated from the laser light source 12 passes through one case body 35a and reaches the imaging range 21 from the lower end opening 36. The reflected light 17 passes through the lower end opening 36 from the imaging range 21, enters the other case body 35b, and is incident on the camera 14.

At this time, one case body 35a surrounds the water surface incidence point 16 to block the waves on the water surface 4, while the other case body 35b surrounds the water surface passage point 18 to block the waves on the water surface 4, preventing the sheet laser light 11 and the reflected light 17 from swaying irregularly in the raw water 2 due to the influence of the waves on the water surface 4.

In addition, when the floating object observation device 10 is installed outdoors, sunlight is blocked by the case 35, preventing the sunlight from entering the camera 14, and a clear image of the flocks 3 can be obtained.

(Fourth embodiment)
In the fourth embodiment, as shown in Figures 8 and 9, by forming the case 35 into a U-shape when viewed from the side, the horizontal distance C2 between the laser light source 12 and the camera 14 is increased from the distance C1 (see Figure 6) shown in the third embodiment, and the imaging depth D2 is increased from the imaging depth D1 (see Figure 6) shown in the third embodiment.

The case 35 has one case body 35a, the other case body 35b, and an intermediate case body 35c connected between the lower part of the one case body 35a and the lower part of the other case body 35b.

The intermediate case body 35c has an intermediate top plate 66 and a pair of intermediate side plates 67. The intermediate top plate 66 is provided between the lower ends of the top plates 60 of both case bodies 35a and 35b. The intermediate side plates 67 are provided between the lower ends of the side plates 62 of both case bodies 35a and 35b.

The intermediate case body 35c is submerged below the water surface 4. The lower end opening 36 is connected to the inside of the intermediate case body 35c, and is formed below the intermediate upper plate 66 and between the lower ends of the pair of intermediate side plates 67. One end of the intermediate case body 35c is connected to the lower end of one case body 35a, and the other end of the intermediate case body 35c is connected to the lower end of the other case body 35b.

As a result, as shown in Figures 6 and 8, the imaging depth can be easily changed to the optimal imaging depth D1, D2 by enlarging or reducing the horizontal distance C1, C2 between the laser light source 12 and the camera 14.

In addition, multiple types of intermediate case bodies 35c with different lengths can be prepared, and the imaging depth can be changed to the optimal imaging depth by replacing these intermediate case bodies 35c.

Fifth embodiment
In the fourth embodiment described above, as shown in Figure 8, the intermediate case body 35c is submerged below the water surface 4, but in the fifth embodiment described below, as shown in Figures 10 and 11, the lower part of the intermediate case body 35c is submerged below the water surface 4 and the upper part of the intermediate case body 35c protrudes above the water surface 4.

Inside the intermediate case body 35c, there exists a water surface 4 and a space 40 formed above the water surface 4 and communicating with the internal spaces 38, 39 of both case bodies 35a, 35b.
This provides the same effects and advantages as those of the fourth embodiment described above.

In the third to fifth embodiments, both case bodies 35a and 35b are formed in a rectangular tube shape, but they may also be formed in a cylindrical shape.

Sixth embodiment
In the third to fifth embodiments described above, a case 35 formed in a V-shape or U-shape when viewed from the side was shown, but in the sixth embodiment described below, the laser light source 12 and the camera 14 are housed in a square box-shaped case 45, as shown in Figures 12 and 13.

The case 45 also functions as a wave breaker 20, and has a rectangular, square-tube body wall 46 and a ceiling 47 provided at the upper end of the body wall 46. The lower part of the case 45 is submerged below the water surface 4, and the upper part of the case 45 protrudes above the water surface 4. The lower end of the case 45 is formed with a lower end opening 36 that opens below the water surface 4. The water surface incidence point 16 and the water surface passage point 18 are inside the case 45. The imaging range 21 is set in the area below the lower end opening 36.

According to this, the sheet laser light 11 emitted from the laser light source 12 passes through the lower end opening 36 from inside the case 45 and reaches the imaging range 21. Also, the reflected light 17 passes through the lower end opening 36 from the imaging range 21, enters the case 45, and is incident on the camera 14.

At this time, the body wall portion 46 of the case 45 surrounds the water surface incidence point 16 and the water surface passage point 18 to block the waves on the water surface 4, preventing the sheet laser light 11 and the reflected light 17 from swaying irregularly in the raw water 2 due to the influence of the waves on the water surface 4.

In addition, when the floating object observation device 10 is installed outdoors, sunlight is blocked by the case 45, preventing the sunlight from entering the camera 14 and allowing clear images of the flocks 3 to be obtained.

Furthermore, as shown by the phantom lines in Figures 12 and 13, the wave-breaking member 20 shown in the first embodiment may be provided inside the case 45. This allows waves on the water surface 4 to be blocked in two stages by the case 45 and the wave-breaking member 20, making it possible to more reliably prevent the sheet laser light 11 and the reflected light 17 from swaying irregularly in the raw water 2 due to the influence of waves on the water surface 4.

In the sixth embodiment, the body wall portion 46 of the case 45 is formed in a rectangular tube shape, but it may also be formed in a cylindrical shape.

In each of the above embodiments, the imaging range 21 is set at the lower end of the case 35, 45, i.e., in an area below the lower end opening 36, but the upper part of the imaging range 21 may be slightly above the lower end opening 36.

In each of the above embodiments, the floating matter observation device 10 is provided in the flocculation tank 1, but it may be provided in a tank other than the flocculation tank 1, such as a settling tank. In addition, although flocs 3, which are an example of floating matter, are observed by the floating matter observation device 10, particles other than flocs 3 may also be observed.

2 Raw water (liquid)
3. Floc (floating matter)
4 Water surface (liquid surface)
10 Floating object observation device 11 Sheet laser light 12 Laser light source 14 Camera (imaging device)
16 Water surface incidence point (liquid surface incidence point)
17 Reflected light 18 Water surface passing point (liquid surface passing point)
20 Wave breaker 21 Imaging range 23, 24 Travel path 30 Light blocking member 35 Case 36 Lower end opening 45 Case

Claims (4)

A floating object observation device for observing floating objects in a liquid, comprising:
A laser light source that irradiates the liquid surface with a sheet laser light that spreads laterally, and an imaging device that images a floating object irradiated with the sheet laser light incident from the liquid surface are provided above the liquid surface,
The point where the sheet laser light is incident on the liquid surface from above the liquid surface is defined as the liquid surface incident point.
If the location where the reflected light that is reflected by the sheet laser light and enters the imaging device passes through the liquid surface is defined as the liquid surface passing location,
A wave breaker is provided to surround the liquid surface incident point and the liquid surface passing point above and below the liquid surface to block waves on the liquid surface;
an imaging range for imaging the floating object irradiated with the sheet laser light by an imaging device is set below the liquid surface;
A floating object observation device, characterized in that a laser light source and an imaging device are arranged so that the traveling path of the sheet laser light and the traveling path of the reflected light are perpendicular to each other in the imaging range. The floating object observation device according to claim 1, characterized in that a light-shielding member is provided between the laser light source and the imaging device to prevent the sheet laser light irradiated from the laser light source and reflected by the liquid surface from entering the imaging device. The opaque case housing the laser light source and the imaging device also serves as a wave breaker,
The liquid level incidence point and the liquid level passing point are inside the case,
A lower end opening that opens below the liquid surface is formed at the lower end of the case,
The sheet laser light passes through the bottom opening from inside the case and reaches the imaging range.
3. The floating object observation device according to claim 1, wherein the reflected light enters the case from the imaging range through the lower end opening. A floating object observation device as described in any one of claims 1 to 3, characterized in that the floating objects are flocs generated by adding a coagulant to the liquid.

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