JPH0968426A - Measuring apparatus for water level - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely measure a water level by using a distance-measuring apparatus of an optical triangulation system. SOLUTION: A distance-measuring module 3 constituted of a projector which projects the light of a light-emitting element onto an object via a projective lens and of a photodetector by which reflected light from the projected object is received via a light receiving lens is built in a housing 2. Then, a reflecting member 5 by which the projected light from the projector at the distance- measuring module 3 is reflected so as to be incident on the photodetector at the distance-measuring module 3 is made to float on a water level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a light projector which projects light from a light emitting element onto an object through a light projecting lens, and a light receiver which receives reflected light from the object through a light receiving lens. The present invention relates to a device for measuring a water level using a distance module, and more specifically, for example, to a water level measuring device installed outdoors in a field.

[0002]

2. Description of the Related Art Conventionally, in a distance measuring device used for an autofocus camera or the like, near infrared light is projected onto an object and the reflected light is imaged on a light receiving element, which changes depending on the distance to the object. A method (optical triangulation method) for obtaining the distance to the object based on the image forming position on the light receiving element is used.

[0003]

When it is attempted to measure the water level by calculating the distance to the water surface using the above-mentioned optical triangulation type distance measuring device, it is determined that the object to be measured is water. However, the near-infrared light is absorbed by this water, so that the reflected light cannot be obtained and the water surface cannot be directly used as the object of distance measurement. Also, there is a limit to the light receiving element or amplification circuit of the distance measuring module, and when the reflected light from the water surface of the sun enters the light receiving element directly, the light intensity of the reflected light of the sunlight is high, so the light receiving element or amplification The circuit is saturated and normal distance measuring operation cannot be obtained.
An object of the present invention is to provide a water level measuring device that can accurately measure the water level using an optical triangulation type distance measuring device.

[0004]

In order to achieve the above-mentioned object, the present invention comprises a projector for projecting light of a light emitting element to an object through a projecting lens, and a light receiving lens for reflected light from the object. A water level measuring device using a distance measuring module composed of a light receiving device for receiving the light via a housing having the built-in distance measuring module, and a distance measuring module that reflects light emitted from a projector of the distance measuring module. It is composed of a reflecting member that floats on the water surface to enter the light receiver. The floating range of the reflecting member on the water surface is regulated so as not to deviate from the luminous flux of the light projected from the projector of the distance measuring module. The reflecting member is preferably formed such that the outer peripheral portion of the surface facing the distance measuring module is lower than the central portion. More preferably, a light shielding member is provided on the outer circumference of the housing.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1, a distance measuring module using an optical triangulation method is provided at the center of the upper inner surface of a hollow cylindrical housing 2 whose lower end is buried in a field floor 1. 3 is fixedly provided. This distance measuring module 3
Each of them is provided with a light projector and a light receiver (both not shown). On the water surface 4 of the field floor 1, a reflection member (float) 5 that is an object to be measured floats. The float 5 moves up and down inside the housing 2 as the water level increases and decreases. In FIG. 1, (L) is the lowest water level,
(H) represents the highest water level. Near-infrared light 3a emitted from a light-projecting element (not shown) built in the projector of the distance measuring module 3 is reflected by the float 5, and the reflected light 3b is reflected.
Is imaged on a light receiving element (not shown) provided in the light receiving device, and the change in the image forming position on the light receiving element due to the change in the distance from the distance measuring module 3 to the float 5 is output from the light receiving element. The distance from the distance measuring module 3 to the float 5 is measured by an optical triangulation method. The reflecting surface of the float 5, that is, the surface facing the distance measuring module 3, is formed in a gentle conical shape that lowers from the central portion toward the outer peripheral portion, and soil, dust, grass or the like is floated by wind and rain. It is designed to prevent deposition on the reflecting surface of No. 5. An error may occur in the distance measurement due to the fluctuation of the floating position of the float 5 on the water surface 4, but the error is within the allowable range of the water level measurement accuracy.

A plurality of air vent holes 2a are formed in a hollow cylindrical housing 2 containing a distance measuring module 3 so that the water levels inside and outside the housing 2 become equal. Four protrusions 2b having a semicircular cross section are formed on the inner wall surface of the housing 2 at equal intervals, and the protrusions 2b regulate the floating position (range) of the float 5. As shown in FIG. 2, when the float 5 is at the position 5a, it is in contact with the two left protrusions 2b, 2b in FIG. 2 and is regulated in the left direction in FIG. Float 5 is in position 5
When it is in position b, it is in contact with the two right protrusions 2b, 2b in FIG. 2 and is regulated in the right direction in FIG. Although not shown, similarly, the float 5 includes the upper two protrusions 2b in FIG.
2b in contact with the upper side of FIG.
The light flux 3 radiated toward the reflection surface of the float 5 is regulated in the downward direction of FIG.
c does not deviate from the float 5. Therefore, the incident light 3a emitted from the light projecting element (not shown) built in the light projector of the distance measuring module 3 is reflected by the reflecting surface of the float 5, and the reflected light 3b is provided in the light receiver. An image can be reliably formed on the light receiving element (not shown). If the clearance between the float 5 and the protrusion 2b is small, dirt, dust, grass or the like will be caught between the inner wall surface of the housing 2 and the float 5, which will hinder the float 5 from rising and falling. A certain amount of clearance is required between the protrusion 2b and the protrusion 2b.

The housing 2 has a tubular shape as a whole so that the distance measuring module 3 is prevented from reaching the reflected light of the external light from the water surface 4. It is more effective if antireflection processing such as applying a matte black coating to the entire inner surface of the housing 2 is performed. In the embodiment shown in FIGS. 1 and 2, the floating position (range) of the float 5 is regulated by the four protrusions 2b formed on the inner wall surface of the housing 2, but the present invention is not limited to this. Alternatively, the floating position (range) of the float 5 may be directly regulated by the inner wall surface of the housing 2. FIG. 3 shows another embodiment of the water level measuring device of the present invention. Components having substantially the same configurations as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. The housing 6 containing the distance measuring module 3 is composed of a tubular portion 6a and a light shielding member 6b. The upper ends of four columns 7 are fixed to the lower surface of the housing 6, and the lower ends of the columns 7 are planted on the field floor 1. The floating position (range) of the float 5 is regulated by the four columns 7. As shown in FIG. 4, when the float 5 is at the position 5a,
The two left columns in FIG. 4 are in contact with and are regulated in the left direction of FIG. When float 5 is in position 5b,
The right two columns 7 and 7 in FIG. 4 are in contact with and are regulated in the right direction in FIG. Although not shown, the float 5 is also used.
4 is in contact with the upper two columns 7 and 7 in FIG. 4 and is subject to the upward regulation in FIG. 4, and is in contact with the lower two columns 7 and 7 in FIG. The light beam 3 c that has been received and is emitted toward the reflecting surface of the float 5 does not deviate from the float 5. If the gap between the float 5 and the strut 7 is small, dirt, dust, grass or the like will be caught between the strut 7 and the float 5, which will hinder the float 5 from rising and falling. A certain amount of space is required between them.

FIG. 5 shows a state in which the reflected light of the sunlight from the water surface 4 is blocked. The sun rays 8a incident from a high position are
Outer edge portion 6c of the light shielding member 6b provided on the outer periphery of the tubular portion 6a
And is reflected by the water surface 4 to become reflected light 8b, which is shielded so as to reach the position of the inner surface 6e of the cylindrical portion 6a after passing through the inner edge portion 6d on one side (right side in FIG. 5) of the light shielding member 6b. The sunlight 9a incident from a low position passes through the outer edge portion 6c of the light shielding member 6b provided on the outer periphery of the tubular portion 6a, and the water surface 4
The reflected light 9b becomes reflected light 9b and is shielded so as to reach the position of the other inner edge portion 6f (left side in FIG. 5) of the light shielding member 6b. Therefore, the light that is incident on and reflected by the water surface from between the sun rays 8a and 9a is reflected by the inner surface 6e of the tubular portion 6a and the light shielding member 6.
It is shielded from the other inner edge portion 6f of b, and the reflected light does not reach the distance measuring module 3. In addition, 8 sun rays
When the sun rays enter from a position higher than a, the sun rays pass through the outer edge portion 6c of the light shielding member 6b, are reflected by the water surface 4 and are outside the one inner edge portion 6d of the light shielding member 6b (see FIG. 5). It is shaded so that it reaches the right side). Also,
When the sun rays enter from a position lower than the sun rays 9a, the sun rays pass through the outer edge portion 6c of the light shielding member 6b, are reflected by the water surface 4, and are reflected on the water surface 4 and the other inner edge portion 6 of the light shielding member 6b.
The light is shielded so as to reach the outside of f (left side in FIG. 5). Therefore, in any case, since the reflected light from the water surface 4 of sunlight having a high light intensity does not reach the distance measuring module 3,
The light receiving element or the amplifier circuit provided in the light receiver is not saturated, and a normal distance measurement result can be obtained. As described above, by setting the distance measuring module 3 so that the reflected light of the external light from the water surface 4 does not reach at the lowest water level, even if the water level rises and the position of the sun changes, the sunlight The reflected light from the water surface 4 does not approach the distance measuring module 3 from the position of the inner surface 6e of the tubular portion 6a. Tube part 6a
It is more effective to apply anti-reflection processing such as applying matte black coating to the entire inner surface of the. The light blocking member 6b has a tubular portion 6
The same light-shielding action is provided at any position on the outer periphery of a, but the outer diameter of the light-shielding member 6b itself becomes larger as the light-shielding member 6b is installed above the tubular portion 6a. If it is installed at the lower end on the water surface side of the cylindrical portion 6a, the outer diameter of the light shielding member 6b itself can be minimized.

FIG. 6 shows another embodiment of the float. The reflecting surface of the float 50, that is, the surface facing the distance measuring module, is formed in a gentle spherical shape so as to decrease from the central portion toward the outer peripheral portion,
Due to wind and rain, dirt, dust, grass, etc. float 5
It is designed to prevent deposition on the 0 reflective surface. By changing the floating position of the float 50 on the water surface,
An error may occur in the distance measurement, but the error is within the allowable range of water level measurement accuracy.

The water level measuring device according to the present invention is interlocked with another device (not shown) to activate alarm means for issuing a warning when the water level in the field exceeds or is below a certain (predetermined) water level. It is also possible to control the entrance and exit gates in the field to maintain an appropriate water level.

[0011]

According to the present invention, it comprises a light projector for projecting light of a light emitting element to an object through a light projecting lens and a light receiver for receiving reflected light from the object of the light projecting through a light receiving lens. The distance measuring module is built in the housing, and the reflecting member for reflecting the light emitted from the projector of the distance measuring module and entering the light receiver of the distance measuring module is floated on the water surface. It is possible to provide a water level measuring device that takes advantage of the triangulation method (claim 1). Since the floating range of the reflecting member on the water surface is regulated so as not to deviate from the luminous flux of the light projected from the projector of the distance measuring module, the incident light emitted from the projector of the distance measuring module is The reflected light can be reflected by the reflecting surface, and the reflected light can be surely incident on the light receiver (claim 2). Since the outer peripheral part of the surface (reflective surface) facing the distance measuring module is formed lower than the central part of the reflective member, the reflective surface of the reflective member may be soil, sand, dust or grass due to wind and rain. It can be prevented from being deposited on the upper surface (Claim 3). Since the light shielding member is provided on the outer circumference of the housing, the reflected light on the water surface of the external light such as the sun rays is blocked,
It is possible to obtain a normal distance measurement result without external light reaching the distance measurement module (claim 4).

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a state in which a water level measuring device according to the present invention is installed in a field.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view of another embodiment of the water level measuring device according to the present invention.

4 is a sectional view taken along line BB of FIG.

5 is a partially cutaway cross-sectional view illustrating reflection of sunlight in FIG.

FIG. 6 is a side view of another embodiment of a reflecting member according to the present invention.

[Explanation of symbols]

 2 Housing 3 Distance measuring module 5,50 Reflecting member (float) 6 Housing 6a Tube part 6b Light blocking member

Claims (4)

[Claims] 1. A distance measuring module comprising a light projector for projecting light of a light emitting element to an object through a light projecting lens and a light receiver for receiving reflected light from the object through a light receiving lens. A water level measuring device that floats on a water surface so as to reflect the light emitted from the housing of the distance measuring module and the light projector of the distance measuring module to enter the light receiver of the distance measuring module. Water level measuring device comprising a reflecting member for 2. The floating range of the reflecting member on the water surface is regulated so as not to deviate from the luminous flux of the light projected from the projector of the distance measuring module. The described water level measuring device. 3. The water level measuring device according to claim 1, wherein the reflecting member is formed such that an outer peripheral portion of a surface facing the distance measuring module is lower than a central portion. 4. The water level measuring device according to claim 1, wherein a light shielding member is provided on the outer periphery of the housing.