JPS62102109A - Instrument for measuring snow depth - Google Patents

Abstract

PURPOSE:To measure highly accurately snow depth by providing the titled instrument with a light source for irradiating light to a snowfall face, a camera for photographing the snowfall face and a data processor for finding out the snowfall depth from information photographed by the camera. CONSTITUTION:A linear light source 1 is directed to the snowfall face and an irradiation line on the snow face is equal to the edge of a section obtained by cutting the snowfall by the surface of ground and an angle theta. The center axis of photographing of the TV camera is rectangularly intersected with the linear light source 1. A dotted line (a) shows the irradiation line due to the linear light source 1 on the ground surface before snow falling and may be moved up to a full line (b) as the result of snow falling. Thereby, snow depth H can be detected by measuring the displacement of the position on a screen formed by the lines (a) and (b). The snow depth can be measured on the basis of equation I in the data processor 3. In the equation, (d) is the moved distance (m) of the linear light source, theta is the irradiating angle (rad) of the linear light source 1 to the ground surface and the snow depth H is obtained by (m).

Description

[Detailed Description of the Invention] [Academic Utilization Meter] This invention relates to a device for measuring snow depth due to snowfall in the natural world.

[Conventional technology]

Figures 1 and 2 are from the Japan Meteorological Agency wired robot snow depth gauge (JMA-7).
This is a diagram of the principle of a conventional snow depth meter shown in the instruction manual (type 9), in which (51 is an ultrasonic transducer, (6)
(7) is a sound velocity correction voltage generator, and (7) is a data converter. Also, (81 is a pole for attaching (61 and (6)).

Next, I will explain about the middle work. Ultrasonic pulses emitted from the transmitter of the ultrasonic transducer (5) are reflected on the snow surface.

This is detected by the receiver of the ultrasonic transducer (5). The delay time from when this ultrasonic pulse is emitted until it returns (T: ultrasonic pulse round trip propagation time [S]) is measured, and the temperature measurement voltage (
t: Measure the qi IFIL) in the middle of the day. Using these measured values and the distance from the ground surface to the transducer (D: this is a known value), the following calculation formula can be used to determine the snow depth.

Lecture H D--CT H: Snow depth (-1D = distance from the ground surface to the transducer [m] C: Sound propagation velocity in the air (sound speed -33) + 0, 613t) [m/
s]T: Ultrasonic pulse round trip propagation time [S]t:
Atmospheric temperature [°C] These calculations are performed in the data conversion device (3).

[Problems to be solved by the invention] Conventional ultrasonic snow depth gauges are configured as described above, and because they measure the propagation time of ultrasonic pulses, the sound waves generated by atmospheric temperature measurements are There were problems such as the need to correct the degree of propagation velocity, and the actual snow depth was measured at a point directly below the ultrasonic transducer, not accurately measuring the entire surface.

This invention was made in order to solve the above-mentioned problems, and it is possible to measure the depth of snowfall without the need for temperature correction, and to measure snowfall depth by capturing snowfall as a surface at specific times. The purpose is to provide a depth measurement device.

[Friendly means of solving problems]

Using the TV camera with snow depth measuring device according to this invention,
By using a line light source that intersects at right angles to the central axis of the image, it is possible to measure snow depth.

[Effect]

The snow depth measuring device according to the present invention processes screen information captured by a TV camera, thereby making it possible to measure snow depth without temperature correction.

[Embodiments of the invention]

Hereinafter, a practical example of this invention will be explained with reference to the drawings. 1st
In the figure, (1) is a line light source, (21 is a TV camera, t
3+ is a data processing device. Also, (4) is a ball for defeating (!1 and (2)).

Next, the operation will be explained. The line light source (1) is directed toward the snowfall surface, and the illumination line going up the snow surface is used to align the snowfall with the ground surface.
It is equal to the edge of the cross section when cut at an angle. Furthermore, the central axis of the TV camera (2) for photographing is perpendicular to the linear light source.

The dotted line a on the screen in the %1 diagram is the irradiation line by the linear light source il+ on the ground surface before snowfall, and due to snowfall, it moves until it reaches the solid line. Therefore, by measuring the displacement of the positions a and bf7) on the screen, the snow depth can be determined from the following calculation formula.

H-dφsinθ H: Snow depth [m] d: Distance traveled by the line light source [m] θ: Irradiation angle of the line light source with respect to the ground surface (In radl, these calculations are (3)
data processing device.

In the above embodiments, the line light source fil is shown as a simple one, but the line light source (1) may be a point light source.

However, in the above actual case, a TV camera (21) was used, but a video camera or other camera may be used.

〔Effect of the invention〕

As described above, according to the present invention, since the snow depth measuring device is configured with a line light source and a TV camera, the snow depth can be measured stably and with high accuracy.

[Brief explanation of drawings]

FIG. 1 is a diagram of the principle of snow depth measurement according to an embodiment of the present invention, and FIG. 2 is a diagram of the principle of a conventional snow depth meter. (1) is a line light source, (21 is a TV camera, (3) is a data processing device, (4) is a mounting ball, (61 ultrasonic transducer), (6) is a sound velocity correction voltage generator, () ) is a data converter, (81 mounting balls).

Claims (5)

[Claims] (1) A snow depth measurement device that includes a light source that emits light toward a snowfall surface, a camera that photographs the snowfall surface, and a data processing device that calculates snowfall depth from information photographed by the camera. (2) The processing method of the data processing device is based on the irradiation angle of the light ray from the light source with respect to the ground, the irradiation position of the irradiation from the light source on the ground surface before snowfall, and the irradiation irradiation from the above light source on the snow surface after snowfall. 2. The snow depth measuring device according to claim 1, wherein the snow depth is detected based on the position of the snow depth measuring device. (3) The processing method of the data processing device is based on the irradiation angle θ of the light ray from the light source with respect to the ground, the irradiation position a irradiated from the light source on the ground surface before snowfall, and the irradiation from the above light source on the snow surface after snowfall. Detect the irradiation position b, and set the depth meter H to H=|
3. The snow depth measuring device according to claim 2, wherein the snow depth measurement device calculates by a−b|sin θ. (4) The snow depth measuring device according to any one of claims 1 to 3, wherein the light source is a line light source. (5) The snow depth measuring device according to any one of claims 1 to 3, wherein the light source is a point light source.