JPH11337662A - Method and device for measuring snowfall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure snowfall, and to eliminate improper measurement caused by the effects of external light and snowfall. SOLUTION: Light emission equipment 63 and an image-pickup device 64 are incorporated in a bowl-shaped cover 61. In this case, distances L1, L2, and L3 are used, where the distance L1 is set to distance from a reference position ORG to a snow plate 3, the distance L2 is set to distance, where fall is made from the ORG to an area near a snow surface 7a on the snow plate 3, and furthermore, the end part of a sensor part is lowered by a specific distance for sliding into snow, and the distance L3 is set to distance of the amount of sliding which is measured by the sensor part while the end part of the sensor part slides into snow, thus calculating the height of the snow cover on the snow plate during a unit time according to L1-L2+L3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring the amount of snow falling at an observation point per unit time.

[0002]

2. Description of the Related Art Snowfall observation includes a method of observing the snow depth of snow accumulated for a long period of time and a method of observing the amount of snowfall per unit time. In the latter observation method, the snow depth from the surface of the accumulated snow is measured every unit time, and the difference between the snow depth measured last time and the snow depth measured this time is used to calculate the snow surface by temperature, stacking, etc. The amount of snowfall per unit time by measuring the amount of snowfall per unit time by compensating the amount of snowfall per unit time. There is a method to measure. The present invention relates to a method and apparatus for measuring snowfall per unit time by the latter method.

There are various methods for measuring the amount of snowfall.
One of them is an optical measurement method using a laser beam.
In the measurement method using this laser beam, the transmitting axis of the laser beam to the observation snowboard and the light receiving axis of the optical sensor are configured differently, and a bright spot is drawn on the snowboard and the snow-covered surface by the laser beam. The light receiving axis receives the reflected light from the light sensor and receives the reflected light from the bright point of the snow-covered plate when snow is not piled up, and the light receiving axis receives the reflected light from the bright point on the snow covered surface with snow A method of measuring the difference in angle between the points and converting this angle into a distance, that is, finding the distance between bright spots by triangulation, and converting this distance into a distance in the vertical direction to measure the amount of snowfall. Used.

[0004] However, this measuring method has a problem that the measurement accuracy is poor because the uneven snow surface is measured at one point. In order to solve this problem, the same applicant has filed a patent application (hereinafter referred to as a prior application) on February 4, 1998, entitled "Method and Apparatus for Measuring Snowfall". This prior application applies a laser beam that is narrow in the front-rear direction and divergent in the lateral direction (that is, a laser beam whose irradiation surface is linear) to a snow plate placed horizontally and a snow surface piled up on the snow plate. Irradiates at regular intervals from an obliquely upward angle to draw a bright line on the snow-covered surface and the snow-covered plate after snow removal. And image the bright line drawn on the snow-covered board, determine a plurality of reference points at equal intervals in the linear image by the bright line of the snow-covered board after snow removal, determine the positions of these reference points, and determine the position For the linear image formed by the bright lines, points at the same interval as this interval were extracted to determine the positions of these extraction points, and the distance between the calculated position of each extraction point and the position of each of the reference points was calculated and calculated. Find the average value of the distance, and calculate the average value of the distance It discloses a method for obtaining the snowfall in terms of distance a straight direction.

[0005]

In the method for measuring the amount of snowfall according to the above-mentioned prior application, the amount of snowfall is measured at the average position of the emission line. Although it can be prevented, there is a problem that the measurement stability is lacking, for example, the laser light is blocked by snowfall during the measurement, or the position of the bright line is erroneously measured due to the influence of extraneous light.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a snowfall amount measuring method and a snowfall measuring method capable of performing stable measurement and measuring with higher accuracy.

[0007]

A method for measuring the amount of snowfall according to the present invention comprises irradiating a measuring object with a linear light beam from obliquely above.
Due to the difference in the bright line position on the measurement target of the linear light beam due to the difference in the distance to the measurement target, a sensor unit that measures the distance to the measurement target was used to accumulate on the snowboard for a unit time. In the snowfall amount measuring method of measuring the snowfall height of the snow with the sensor unit and measuring the snowfall amount, when the sensor unit is lowered from a reference position to the snowboard before the snowboard has no snowfall yet. The first step in which the distance L1 is measured in advance, at the time of measurement, the sensor unit is lowered from the reference position to the vicinity of the snow surface on the snow-covered board, and a predetermined distance is dropped so that the end of the sensor unit enters the snow. A second stage of measuring the distance L2 when the sensor is moved, a third stage of measuring the amount of infiltration as the distance L3 using the sensor unit in a state where the end of the sensor unit is sunk into snow, L1- L
A fourth step of calculating a snow height of snow accumulated on the snow plate for a unit time by 2 + L3.

Further, the snowfall amount measuring apparatus of the present invention irradiates a linear light beam to the object to be measured from obliquely above, and detects the difference in the position of the bright line on the object due to the difference in the distance to the object to be measured. A sensor for measuring the distance to the object to be measured, and a snowfall measuring device for measuring the snowfall by measuring the snowfall height of snow accumulated on the snowboard for a unit time by the sensor. Means for raising and lowering the sensor unit on the snow plate, storage means, and arithmetic means, wherein the sensor unit is lowered from a reference position to the snow plate before measurement without any snow on the snow plate. A distance L1 at the time, and a distance L2 when the sensor unit is lowered from the reference position to a vicinity of the snow surface on the snow-covered plate at the time of measurement and further lowered a predetermined distance so that the end of the sensor unit enters the snow. Put the end of the sensor part in snow Ri in written allowed state, using the slip amount of the distance L3 measured using the sensor unit, L1-
L2 + L3 is used to calculate the snow height of the snow accumulated on the snow plate during the unit time.

[0009] The sensor section is provided in a bowl-shaped cover.
A light emitter for irradiating the measurement object with a linear light beam from obliquely above, and an imaging device connected to an image analyzer to determine the difference in the bright line position are built in, and the end of the sensor unit is exposed to snow. The measurement of the amount of infiltration L3 performed in a state of being submerged is performed by intercepting extraneous light or snowfall with the cover.

Further, there is provided a means for raising and lowering the snowboard at the same height position as the snow surface in the vicinity of the measurement location measured by the sensor section.

In order to measure the height position of the snow surface in the vicinity of the measurement location and to prevent the snowfall on the snow-covered plate from being hindered, there is provided means for rotating the sensor unit in a horizontal plane. .

[0012] The snowboard may be provided with separate heaters on the front and back sides with a heat insulating material interposed therebetween, and may be provided with means for rotating about a longitudinal direction. Melt the snow and rotate it around the longitudinal direction to remove the snow.The next time the measurement is performed, the snow on the back side is measured, and after the measurement, the snow on the back side is melted by operating the heater on the back side. It is characterized by rotating around the direction to remove snow and thus alternately using the front and back surfaces every time measurement is performed.

Further, a computer control device is provided, and a series of measurement operations are performed by automatic control under program control or remote control via a communication line.

The snowfall measuring method and apparatus according to the present invention, having the above-described structure, can measure the height of the snow in the cover extremely accurately, thereby preventing erroneous measurement due to extraneous light or snowfall. And accurate snowfall measurement is possible.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing one embodiment of the device configuration of the snowfall measuring device of the present invention. In FIG. 1, reference numeral 1 denotes a support, and the support 1 includes a main shaft 10 and a sub shaft 1.
1 and the snow plate drive mechanism 12, and the snow plate drive mechanism 12 performs an operation of moving the snow plate 3 up and down in the arrow (A) direction (the Z direction in three-dimensional XYZ coordinates). 2
Reference numeral denotes a snow plate and a sensor unit rotating mechanism. The operation of rotating the snow plate 3 in the direction of the arrow (B) with the dotted line (b) as the rotation axis by a drive mechanism (not shown), and the rotation of the dotted line (c) with the rotation axis Is performed in the XY plane to rotate the sensor unit 6 in the direction of the arrow (C). Reference numeral 4 denotes a sensor unit supporting mechanism, and reference numeral 5 denotes a sensor unit elevating mechanism, which performs an operation of moving the sensor unit 6 up and down in the arrow (D) direction.

Reference numeral 6 denotes a sensor unit. The sensor unit 6 has a positioning sensor 62 in a cover 61 having a U-shaped cross section.
, A semiconductor laser light emitter 63 and a CCD camera 64. The positioning sensor 62 is used for positioning the descending position of the sensor unit 6 (the position where the end of the sensor unit 6 comes to the snow surface) when measuring the amount of snowfall (that is, when there is snow on the snowboard 3). For example, a photoelectric sensor is used as the sensor, and the descending position of the sensor unit 6 is determined based on the intensity of the reflected light from the snow-covered surface. However,
In a positioning sensor using a photoelectric sensor, a reaction distance (stop position) is slightly different due to a difference in snow quality or the like. Therefore, if the position of the snow surface is measured only by the positioning sensor 62, accurate measurement can be performed. I can't. Therefore, as described below, in the present invention, the sensor unit 6 is lowered in two stages when snow is present, and the position of the snow surface is accurately measured.

The apparatus shown in FIG. 1 is provided with storage means such as a memory, arithmetic means such as a CPU, and an image analyzer connected to a CCD camera 64 for measuring a difference between bright line positions. However, these are omitted in FIG. This type of device also has a computer control device,
Generally, automatic measurement can be performed by program control or remote control via a communication line, but these computer control devices and the like are also omitted in FIG.

FIG. 2 is a diagram for explaining the principle of measuring snowfall according to the present invention. In FIG. 2, L1 is the distance traveled when the sensor unit 6 is lowered from the initial position (ORG) to the snowboard 3 when there is no snowfall, and L2 is the sensor distance from the ORG when snowfall is present on the snowboard. L3 is the distance traveled when the end is sunk into snow by descending to the surface, and the end is sunk into the snow. L3 is the measurement distance from the end when the end of the sensor unit 6 is sunk into the snow to the snow surface 7a. Is shown. If the position of the snow surface is measured only by the positioning sensor 62 as described above, accurate measurement cannot be performed. Therefore, in the present embodiment, as shown in FIG. 2B, the sensor unit 6 is further lowered by a predetermined distance from the snow surface position captured by the positioning sensor 62 so that the end of the sensor unit 6 enters the snow. The distance from the end to the snow surface 7a (that is, the sensor unit 6
The correct distance L3 at which the end has sunk into the snow is measured by the semiconductor laser light emitter 63 and the CCD camera 64, and the correction is performed.

Next, the operation of measuring the distance L3 will be described. The semiconductor laser light emitter 63 irradiates a linear laser beam parallel to the Y direction on the snow plate 3 at a predetermined angle (ie, irradiates the snow plate 3 at a predetermined angle from the vertical direction of the snow plate 3). The inside is imaged from a substantially vertical direction. When there is no snow on the snow plate 3, the end of the sensor unit 6 contacts the snow plate 3, as shown in the lower diagram of FIG. In addition, the CCD camera 64 captures an emission line of the laser light at the approximate center of the snow plate 3 as the base line 8.

When there is snow on the snow plate 3, the sensor 6
When the end of the laser beam is sunk, the laser beam is reflected by the snow surface 7a on the way, and the position of the bright line imaged by the CCD camera 64 moves (see 8a in the lower diagram of FIG. 2B).
Therefore, the amount of penetration (distance L3) at the end of the sensor unit 6 can be measured from the moving distance of the bright line. The moving distance of the bright line is measured by using the CCD camera 64 and an image analyzer (not shown) connected thereto as described above. Then, as is apparent from FIG.
By obtaining a provisional snowfall amount in a state where the sensor unit 6 is sunk by -L2, and adding and correcting the penetration amount L3 from the provisional snowfall amount, an accurate snowfall height can be measured. In the present embodiment, the position of the snow surface 7a can be accurately measured with the end of the sensor unit 6 provided with the cover 61 sunk into the snow. Erroneous measurement such as erroneous measurement of the position of the bright line due to the influence of light can be eliminated, and stable and accurate measurement can be performed.

FIGS. 3A and 3B are diagrams for explaining the operation of the snowfall measuring device shown in FIG. 1. FIG. 3A shows a state at the start of measurement, FIG. 3B shows a state at the time of measurement, and FIG. Is the state at the time of snow removal,
(D) shows the state at the start of the next measurement. At the start of the measurement, the snowboard drive mechanism 12 is operated to move the snowboard 3 up and down to the same height as the ground surface. In other words, since the amount of snowfall is usually measured with reference to the ground surface, it may be necessary to place the snowboard 3 at a position different from the ground surface (or the snow surface if there is snowfall) and measure the amount of snowfall with the snow piled on it. Large measurement errors occur. Therefore, at the start of the measurement, FIG.
The snow plate 3 is placed at the same height as the ground surface, and the sensor unit rotating mechanism 2 is operated for the same reason as shown in FIG.
Is turned away from the snow plate 3 (in FIG. 3A, it is shifted by 90 degrees on the XY plane). The position of the snow surface around the snow plate 3 can be measured using the sensor unit 6 located at this position, and the information is fed back to the snow plate drive mechanism 12 so that the snow plate 3 is at the same height as the snow surface. Is positioned.

After a lapse of a predetermined time, the sensor unit 6 is returned to the snow plate 3 as shown in FIG. 3B, and the height of the snow accumulated on the snow plate 3 during this time is measured by the sensor unit 6 in two steps as described above. And measure by L1-L2 + L3. When the measurement of the height of the snow cover is completed, an operation of removing snow accumulated on the snow plate 3 is performed. The snow removal operation is carried out by a heater (not shown in FIG. 3, which is not shown in FIG. 3 but is separately provided on the front and back surfaces of the snow plate 3 with a heat insulating material interposed therebetween). The surface of 3 is heated to make it easy to fall snow, and as shown in FIG. 3 (C), the snow plate 3 is turned around the X direction to discharge snow. For this reason, the snowboard drive mechanism 12
As a result, the snow plate 3 is raised in the Z direction, and the snow plate rotating mechanism 2 rotates the snow plate 3 around the X direction.

That is, once stopped at the position rotated by 90 degrees, the snowfall is dropped and the snow is removed, and the surface is further rotated by 90 degrees. In the next measurement, the surface which was the back surface last time is used as the front surface. In addition, the snow that has been removed falls just below the snow-covered plate 3 where the snow cover has been blocked, and its snow surface is substantially at the same position as the surrounding snow surface. Therefore, as shown in FIG. May be started at the same position, or the snow plate 3 may be placed at a position shifted from the XY plane by 90 degrees (not shown) to start the measurement. The height position of the snow plate 3 in the next measurement is the current snow surface obtained by adding the snow height position measured to the first snow surface.

In the above-described embodiment, the semiconductor laser light emitting device 63 and the CCD camera 64 are used in the sensor section. However, a general light emitting device that irradiates a linear light beam from obliquely above and a general light emitting device that can capture an image. And a simple imaging device. The cover 64 of the sensor unit 6
Has a horizontal U-shaped cross section, but any so-called bowl-shaped cover may be used.

[0025]

As described above, the method and the apparatus for measuring the amount of snowfall according to the present invention can measure the height of snowfall within the cover of the sensor part very accurately by employing the above-described structure. This has the effect of preventing erroneous measurement due to extraneous light or snowfall, and enabling extremely accurate measurement of the amount of snowfall.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a device configuration of a snowfall amount measuring device of the present invention.

FIG. 2 is a diagram for explaining the principle of measuring snowfall according to the present invention.

FIG. 3 is a diagram for explaining an operation of the snowfall amount measuring device shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support part 2 Snow plate and sensor part rotation mechanism 3 Snow plate 4 Sensor part support mechanism 5 Sensor part elevating mechanism 6 Sensor part 7 Snow cover 7a Snow surface 61 Cover 62 Positioning sensor 63 Semiconductor laser 64 CCD camera

Claims (7)

[Claims] 1. A measuring object is irradiated with a linear light beam from obliquely above, and the distance to the measuring object is determined by the difference in the position of the bright line on the measuring object due to the difference in the distance to the measuring object. In a snowfall amount measuring method of measuring a snowfall height by measuring the snowfall height of snow accumulated on a snowboard during a unit time using a sensor unit for measuring, the snowfall plate does not yet have snowfall. A first stage in which a distance L1 when the sensor unit is lowered from a reference position to the snow plate before measurement is measured in advance, and the sensor unit is positioned near the snow surface on the snow plate from the reference position during measurement. A second step of measuring a distance L2 when the sensor unit is lowered to a predetermined distance in order to lower the sensor unit end into snow, and while the sensor unit end is sunk into snow, And use this distance to A third step of measuring as L3, and a fourth step of calculating the snow height of snow accumulated on the snowboard during a unit time by L1-L2 + L3, the method comprising: . 2. A measurement object is irradiated with a linear light beam from obliquely above, and the distance to the measurement object is determined by the difference in the position of the bright line on the measurement object of the linear light beam due to the difference in the distance to the measurement object. A snowfall amount measuring device having a sensor unit for measuring, and measuring the snowfall height of snow accumulated on the snowboard during a unit time by the sensor unit to measure the amount of snowfall; A means for moving the sensor unit down from a reference position to the snow plate before measurement, wherein there is no snow on the snow plate.
A distance L2 when the sensor unit is lowered from the reference position to a vicinity of a snow surface on the snowboard at the time of measurement, and is further lowered a predetermined distance so that the end of the sensor unit is sunk into snow; With the part sunk into the snow, using the distance L3 of the sunk amount measured using the sensor unit, the snow height of the snow accumulated on the snowboard during the unit time is calculated by L1-L2 + L3. A snowfall amount measuring device characterized by the following configuration. 3. The sensor section is connected to a light-emitting device for irradiating a linear light beam obliquely onto the object to be measured in a bowl-shaped cover, and to an image analyzer for judging a difference in the bright line position. The measurement of the amount of infiltration L3 performed in a state in which the end of the sensor unit is submerged in snow is performed by blocking the entry of extraneous light or snowfall by the cover. Item 3. The snowfall amount measuring device according to Item 2. 4. The apparatus according to claim 2, further comprising means for raising and lowering the snowboard at a position at the same height as a snow surface in the vicinity of a measurement location measured by the sensor unit. Snowfall measurement device. 5. A means for rotating the sensor section in a horizontal plane for measuring a height position of a snow surface near a measurement place and for not hindering snowfall on the snowboard. The snowfall amount measuring device according to any one of claims 2 to 4. 6. The snowboard is provided with separate heaters on the front and back sides with a heat insulating material interposed therebetween, and is provided with means for rotating around a longitudinal direction, and operates the heater on the front surface for snow that has snowfall on the surface after measurement. Then, the snow is removed by rotating the longitudinal direction as an axis, and the next measurement is carried out with the snow on the back side, and the measurement is performed.After the measurement, the snow on the back side is melted by operating the heater on the back side, and The snowfall amount measuring apparatus according to any one of claims 2 to 5, wherein the apparatus is configured to rotate around the longitudinal direction to discharge snow, and to alternately use the front and back surfaces each time measurement is performed. . 7. A computer control device according to claim 2, wherein a series of measurement operations are performed by automatic control under program control or remote control via a communication line. The snowfall measurement device as described.