JPH0526665A - Water level measuring device - Google Patents

Abstract

PURPOSE:To measure the water level in the noncontact state with the water surface without disturbing the flow of a fluid and the state of waves, measure the water level at many points with one measuring device, and precisely measure the high-frequency wave height. CONSTITUTION:A water level measuring device is constituted of a slit light source device 1 projecting the light from a light source 2 to the water surface via a slit plate 4, an image pickup device 11 photographing slit images 9a, 9b obtained when the slit light from the slit light source device 1 is reflected on the water surface, and an image processor 12 calculating the height of the water surface based on the data of the slit image obtained by the image pickup device 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water level measuring device for measuring the height and wave height of a water surface by using image processing means.

[0002]

2. Description of the Related Art Capacitance type wave height meters and servo type wave height meters are known as conventional wave height measuring devices. First, in the capacitive wave height meter, as shown in FIG. 7, the detection line 32 supported by the support 31 is inserted into the water 34 from the detection unit 33, and the detection unit 33 moves the detection line 32 to water by moving the water surface above and below. The height to be immersed is detected, and the detected value is converted into a change in electric capacity, converted into a peak value by the crest meter main body 35, and displayed.

On the other hand, in the servo wave height meter, as shown in FIG. 8, a detection needle 42 is provided in a detection portion 41 having a built-in servo motor, and the lower end of the detection needle 42 is immersed in water 43 for about 2 mm to form a water bottom. While monitoring the change in electric resistance between the earth rod 44 embedded in the
The detection needle 42 is moved up and down by a servo motor so that the electric resistance is always constant. Thereby, the wave height can be calculated in the wave height meter main body 45 from the vertical movement amount of the detection needle 42 and displayed.

[0004]

However, since such a conventional wave height measuring device is constructed as described above, the detection wire 32 and the detection needle 42 must be immersed in the water surface, and the flow of water or liquid is to be diminished. Accurate measurement values cannot be obtained due to disturbance of the wave condition and wave condition, which is a serious problem especially in measurement in a narrow channel or multi-point measurement, and a measurement error of ± 0.3
Since it is about millimeter, there is a problem that a minute peak value of 0.1 milli-order cannot be measured.

Further, the responsiveness of each of the detection units 33 and 41 is low, for example, about 5 Hz, so that not only the peak value of a high frequency cannot be measured, but in multipoint measurement, the same number of measuring devices as the number of measuring points are prepared, or There was a problem that a troublesome work was required, such as changing the installation of one or more measuring devices.

Further, in the case where a multipoint measurement in a horizontal row is to be performed in a place such as a long and narrow waterway, the detection units 33 and 4 are used.
There is a problem that multi-point measurement cannot be performed because there is a restriction due to the size of 1 and the number of installations.

The present invention has been made by paying attention to the conventional problems as described above.
Moreover, it is an object of the present invention to provide a water level measuring device that enables measurement of wave heights and water levels at multiple points with a single measuring device and high-frequency wave height measurement with high accuracy.

[0008]

A water level measuring device according to the present invention provides a slit light source device for projecting light from a light source onto a water surface through a slit plate, and a slit light from the slit light source device to obtain on the water surface. An image pickup device for picking up a slit image formed by the image pickup device, and the height of the water surface is calculated by an image processing device based on position data or area data of the slit image obtained by the image pickup device. ..

[0009]

In the image pickup device according to the present invention, the slit light source device takes an image of the slit image obtained on the water surface, and the image processing device makes the height of the water surface based on the image data as the position data or area data of the slit image. The water level and the peak value are calculated, and the calculation result is displayed on a monitor, printed paper, or the like as needed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In FIG. 1, 1 is a slit light source device, which comprises a light source 2 such as a halogen lamp, a slit plate 4 having a slit 3, and a condenser lens 5,
These are arranged on the same optical axis. Reference numeral 6 denotes a water tank arranged below the slit light source device 1. The water tank 6 contains water 7 (including other liquids) colored in white so as to reflect the slit light. 8 is slit light projected from the slit light source device 1, 9a and 9b are reflected light of a slit image formed on the water surface, and 10 is this slit image 9
The image pickup device of the CCD camera 11, which is an image pickup device for picking up images a and 9b, 12 is an image processing device that calculates the height of the water surface based on the position data and area data of the slit image obtained from the image pickup device, and 13 is It is a monitor attached to the image processing device 12, which appropriately displays an image by the CCD camera 11, water level data as a processing result, and the like. Also, 14
Is a cable connecting the CCD camera 11 and the image processing device 12.

Next, the operation will be described. First, the light source 2
When the light is emitted from the slit light, the slit light having passed through the slit 3 of the slit plate 4 is applied to the water surface in a band shape. When the water level is P1 and there is no change, the slit image on the water surface becomes reflected light 9a and enters the CCD camera 11. C
In the CD camera 11, the slit image is received by the image pickup device 10 and is input to the image processing device 12 as image image data. The image processing device 12 processes this image data and displays it as a slit image D1 at substantially the center of the monitor 13.

On the other hand, when the water level changes to P2, the slit image comes to a higher position on the water surface.
The reflected light 9b changes as shown by the dotted line, and is imaged at a position different from the above on the image pickup device 10 in the CCD camera 11. Then, this image formation data is used as the image processing device 1.
2 is input and the same arithmetic processing as above is performed. The processing result is displayed on the monitor 13, for example, on the right side, which is far from the slit image D1. Therefore, by reading the position of the slit image D2 from the slit image D1 and the scale displayed on the monitor 13, the water level and the peak value can be easily obtained.

In this case, it is optional to read the positions of the slit images D1 and D2 with respect to the left and right edges and the center position of these slit images D1 and D2. In addition, if it is confirmed in advance how much (the number of dots) the image moves due to the change of the water level on a scale such as a block gauge whose height is known, the slit image D obtained by the image processing can be obtained.
By multiplying the movement amount of 2 by a certain constant, the change value of the water level can be obtained.

By properly designing the optical system including the angle of the CCD camera 11 from the horizontal plane, the distance from the horizontal plane, and the lens 5, a resolution of about 0.05 mm can be easily realized, and conversely the resolution can be increased. It is also possible to increase the measurement range to several centimeters.

By the way, in such a water level measuring device, the responsiveness of the measurement is determined by the time when the CCD camera 11 takes in the slit image and the time when the moving coordinate (position) is calculated, and in general, the timer slits once every 33 milliseconds. Images can be captured. Therefore, even if the coordinate calculation processing time of 5 milliseconds is added to this time, an image can be obtained every 66 milliseconds, and as a result, the responsiveness can be increased to about 15 hertz. Furthermore, if the image processing apparatus is equipped with an extended memory (storage device) to record all the images and then perform coordinate calculation, the responsiveness will be 3
It will be possible to increase it to 0 Hz. When measuring the height of a high frequency wave, the image capture time 33
If the wave changes significantly in milliseconds, the CCD camera 11
In this case, a camera equipped with an electronic shutter or a strobe light source may be used, because the image photographed in (3) will shake.

2 (a) and 2 (b) are different from those in which one slit 3 is provided on the slit plate 4, three slits 3a are provided at regular intervals in the longitudinal direction. 2 shows a slit plate 4a for use with slits and a slit plate 4b for multiple points provided with three triangles. First, in the case of using the slit plate 4a shown in FIG. 2A, when a wave P4 is generated with respect to the stationary water level P3 as shown in FIG. 3, the slit image generated by this wave P4 is orthogonal to the paper surface. CC from direction
When the image is captured by the D camera 11, as shown in FIG. 4, a slit image D4 by waves is displayed on the monitor 13 with respect to the slit image D3 at the still water level. Therefore, if the amount of movement of the slit image D4 with respect to the slit image D3 is obtained by the image processing device 12 and read on the monitor 13, the peak values of multiple points can be simultaneously and accurately measured by one device.

Further, when the slit plate 4b of FIG. 2 (b) is used, a slit image D5 as shown in FIG. 5 (a) is obtained at the still water level. Therefore, when the image processing apparatus 12 further applies window processing to this to obtain a slit image D6 as shown in FIG. 5B, when a wave P4 as shown in FIG. 3 occurs, A slit image D7 as shown in FIG. 5C is obtained. And this Figure 5
When the area of each independent block of the slit image D7 in (c) is obtained by the image processing device 12, the water levels at multiple points can be obtained at the same time. However, in this case, it is necessary to obtain the relationship between the moving distance and the area in advance.

Further, although it is not a multipoint measurement, even if the above-mentioned simple slit plate 4 having one slit 3 is used, a vertical width window (window deviated by 90 ° from FIG. 5B) is obtained. If the distance is set at an appropriate interval, the measurement point can be moved within the range where the slit light 8 is projected without moving the measuring device.

FIG. 6 illustrates the slit light source device 1 of the present invention in more detail. According to this, the plurality of light sources 2 are mounted in the case 22 by the supporting member 21, the cooling fan 23 for discharging the hot air generated by the light sources 2 is provided behind (upper) the light source 2, and the cooling fan 23 is provided in front of it. A frosted glass plate 24 for diffusing is disposed. Reference numeral 25 is a support member for the slit plate 4, and 26 is a power cable. The operation of the slit light source device 1 is as described above, and the duplicated description is omitted here.

In the above embodiment, the wave height data finally obtained by signal processing by the image processing device 12 is used as the monitor 1.
Although the case of confirming in 3 was explained, the wave height data can be transferred to a personal computer and recorded in a storage device. In this case, the start and end of measurement and the start and end of signal processing can be performed. Makes comprehensive management of the measurement system easy.

In the above embodiment, the case where the slit image is obtained by using the CCD camera 11 is shown. However, an image recorded on a video tape by using a video camera having a silicon vidicon or other image pickup device as an image pickup device. The slit image can also be obtained by processing the above, and the same effect as that of the above-described embodiment can be obtained.

[0022]

As described above, according to the present invention, the slit light source device for projecting the light from the light source on the water surface through the slit plate, and the slit image obtained on the water surface by the slit light from the slit light source device. Since the image processing device is configured to obtain the height of the water surface by calculation based on the position data or the area data of the slit image obtained by the imaging device, It is non-contact and can measure the water level or wave height with high accuracy without affecting the flow or wave conditions. By setting the CCD camera position and lens system appropriately, it is possible to easily achieve a high resolution of 0.05 mm. Can be realized. Further, since the response of the measurement system is good, there is an effect that it is possible to measure a high-frequency wave height of about 15 hertz. Further, by appropriately setting the slit light and the image processing window, it is possible to simultaneously measure multiple points with one device without moving the device.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a water level measuring device according to an embodiment of the present invention.

2A and 2B are plan views showing another embodiment of the slit according to the present invention.

FIG. 3 is an explanatory diagram showing a method of obtaining a slit image of waves at multiple points using the slit shown in FIG.

4 is a monitor display explanatory diagram showing a slit image obtained by the method shown in FIG. 3. FIG.

5 (a) to 5 (c) are monitor display explanatory views showing respective slit images at the time of stationary water level, window processing, and wave generation, which are obtained by using the triangular slits shown in FIG. 2 (b). ..

FIG. 6 is a structural diagram showing details of a slit light source in FIG.

FIG. 7 is a configuration diagram showing a conventional capacitive wave height meter.

FIG. 8 is a configuration diagram showing a conventional servo-type wave height meter.

[Explanation of symbols]

 1 Slit light source device 2 Light source 3 Slit 4 Slit plate 11 Imaging device 12 Image processing device 13 Monitor

Claims (1)

Claim: What is claimed is: 1. A slit light source device for projecting light from a light source onto a water surface through a slit plate, and an image pickup for picking up a slit image obtained on the water surface by the slit light from the slit light source device. A water level measuring device comprising: a device; and an image processing device that calculates the height of the water surface based on position data or area data of a slit image obtained by the imaging device.