JPH06109469A - Distance measuring method - Google Patents

Abstract

PURPOSE:To easily measure an accurate distance on the basis of a simple theory. CONSTITUTION:The laser beam emitted from one light source 1 is split into two laser beams opened at a constant angle theta by the optical machinery 3 provided at the spectral point 2 in front of the light source and the speced-apart distance (h) between two laser beams at the measuring point 4 present at a place separated from the spectral point 2 is measured. The distance D between the spectral point 2 and the measuring point 4 is calculated from the spaced- apart distance (h) and the angle theta on the basis of D=h/{2tan(theta/2)}.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring method for measuring a distance between two points by using a light beam such as a laser beam and is used for distance measuring in the field of civil engineering and construction. It is a thing.

[0002]

2. Description of the Related Art Conventionally, there are various methods for measuring the distance between two points, and, for example, surveying by a tape measure, stadia surveying, surveying by an optical wave rangefinder, etc. are generally used.

[0003]

However, the above distance measuring method has the following problems. Although surveying with a tape measure is simple and is often used at present, the measurement distance is short at about 50 m at the longest, and if there is an obstacle in the measurement section, the measurement cannot be performed straightly, resulting in a measurement error. Moreover, for example, it is not possible to measure the distance across a wide river. Measurement using stadia surveying and light wave rangefinders has high measurement accuracy and is also often used, but it is easy for anyone to use because it is necessary to know the operation method of the equipment before use. It cannot be used for. Also, the purchase cost of the equipment is high.

An object of the present invention is to provide a distance measuring method which can easily perform accurate distance measurement with a simple principle.

[0005]

The distance measuring method of the present invention is, as shown in FIG. 3, an angle θ between two light beams that spread straight from a spectral point 2 by a constant angle θ and a distance D from the angle. Between the separation points h of the two light beams at the measurement point 4 at a distance of only D × 2 × tan (θ / 2) = h
It was developed based on the relationship
That is, according to the distance measuring method of the present invention, as shown in FIGS. 1 and 2, the optical beam emitted from the light source 1 is opened at a certain angle θ by the optical device 3 provided at the spectral point 2 ahead of the one light source 1. 2 light beams, and the separation distance h of the two light beams at a measurement point 4 located apart from the spectroscopic point 2 is measured. From the separation distance h and the angle θ, the spectroscopic point 2 is obtained. The distance D to the measurement point 4 is D = h / {2tan (θ
/ 2)} is used for the calculation.

[0006]

In the distance measuring method of the present invention, as shown in FIG. 3, since the angle θ of the two light beams is fixed, the separation distance h between the two light beams at the measuring point 4 can be adjusted by an appropriate means. The distance D between the spectral point 2 and the measuring point 4 is D
= H / {2tan (θ / 2)}.

[0007]

Embodiment 1 An embodiment of the distance measuring method of the present invention is shown in FIG. In this, the light source 1 is installed at one of the spectral points 2 and 4 for measuring the distance. The light source 1 outputs a light beam with a small divergence. For example, a pointer using a visible light semiconductor laser using an aspherical lens that can easily realize a spot having a width of about 5 to 6 mm even at a distance of 30 m. To use.

A beam splitter (optical device) 3 for dividing the light beam emitted from the light source 1 into two light beams and emitting the light beam is arranged in front of the light source 1. The beam splitter 3 splits the incident light beam into two by a 45 ° half mirror 12 and allows one of the light beams to go straight ahead and to be emitted, while the other light beam is a 45 ° -ψ total reflection mirror 13. The light beam is opened by 2φ and emitted. Since this angle ψ is fixed and its value is known in advance, the angle θ of the two light beams can be obtained as 2ψ.

A measuring plate 1 for projecting the two light beams emitted from the beam splitter 3 on the other measuring point 4.
Install 5. The measurement plate 15 is a large flat plate on which the two light beams are projected, and the measurement person
The separation distance h of the light beam projected on the beam 5 can be measured using a ruler or the like. During this measurement, the measurement plate 15
It is necessary to adjust the orientation and height of the measuring plate 15 so that the intermediate axis 14 of the two light beams is projected vertically.

In the present invention, instead of the measuring plate 15, a photodiode array having a large number of photodiodes arranged on the surface is arranged, and the position of the light beam projected on it is automatically detected. May be processed by a computer or the like to obtain the isolation distance h.

To obtain the distance D between the spectroscopic point 2 and the measuring point 4 from the separation distance h of the two light beams and the angle θ of the two light beams at the measuring point 4 thus obtained, the relational expression D × 2 × tan (θ / 2) = h, that is, D = h / {2ta
It may be obtained based on n (ψ)}. Strictly speaking, however, the distance D obtained in this way is not the distance D between the spectral point 2 and the measurement point 4 but the point 16 as shown in FIG.
And the measurement point 4. This point 16 intersects when the two light beams are temporarily extended to the left side in the drawing. Therefore, if the distance r between the point 16 and the spectral point 2 is obtained in advance by an experiment or calculation and the distance r is subtracted from the distance D, the distance D between the spectral point 2 and the measuring point 4 can be more accurately obtained. Is required.

[0012]

Second Embodiment Another embodiment of the distance measuring method of the present invention is shown in FIG.
Shown in. In this embodiment, of the spectral points 2 and 4 for measuring the distance, one of the spectral points 2 is a corner cube (an optical device) that reflects the light beam emitted from the light source 1 similar to that in the first embodiment. ) Install 3.

This corner cube 3 has its entrance surface 2
It is a prism that allows the light beam incident on the beam No. 1 to be emitted from the same incident surface 21 by shifting it by 2ψ with respect to the incident direction. This corner cube 3 can be manufactured by cutting one piece of a right-angled prism by an angle ψ as shown in FIG.

At the other measuring point 4, the light source 1 and the measuring plate 15 are installed. The measurement plate 15 is a large flat plate, in which a hole 22 for emitting the light beam of the light source 1 is formed, and the light beam reflected by the corner cube 3 and returned is projected. The separation distance h between the light beam emitted through the hole 22 of the measuring plate 15 and the light beam returned by the corner cube 3 can be measured with a ruler or the like. When performing the measurement, it is necessary to adjust the direction and height of the measurement plate 15 so that the central axes 14 of the both light beams are vertically projected on the measurement plate 15, as in the first embodiment.

In the present invention, instead of the measuring plate 15, a photodiode array having a large number of photodiodes arranged on the surface is arranged to automatically detect the position of the light beam projected on the photodiode array, and the detection signal thereof is detected. May be processed by a computer or the like to obtain the isolation distance h.

In order to obtain the distance D between the spectroscopic point 2 and the measuring point 4 from the distance h between the two light beams at the measuring point 4 thus obtained and the angle θ between the two light beams, a relational expression is used. D × 2 × tan (θ / 2) = h, that is, D = h / {2ta
It may be obtained based on n (ψ)}. Strictly speaking, however, the distance D obtained in this way is not the distance D between the spectral point 2 and the measurement point 4 but the point 16 as shown in FIG.
And the measurement point 4. This point 16 intersects when the two light beams are temporarily extended to the left side in the drawing. Therefore, if the distance r between the point 16 and the spectroscopic point 2 is obtained in advance by experiment or calculation and the distance r is subtracted from the distance D, the distance D between the spectroscopic point 2 and the measuring point 4 will be more accurate. Is required.

[0017]

According to the distance measuring method of the present invention, a light beam emitted from one light source 1 is made into two light beams opened at a certain angle θ at the spectral point 2, and these two light beams are used. The distance D between the spectroscopic point 2 and the measuring point 4 can be easily obtained only by measuring the separation distance h of the measuring point 4.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of a distance measuring method according to the present invention.

2A is a schematic view showing another embodiment of the distance measuring method of the present invention, and FIG. 2B is an explanatory view showing an example of a corner cube used in the distance measuring method of FIG.

FIG. 3 is an explanatory diagram showing the principle of the distance measuring method of the present invention.

FIG. 4 is an explanatory diagram of distance measurement in the distance measurement method of FIG.

5 is an explanatory diagram of distance measurement in the distance measurement method of FIG.

[Explanation of symbols]

 1 Light source 2 Spectral point 3 Optical equipment 4 Measurement point

Claims (1)

[Claims] 1. A light beam emitted from the light source 1 is made into two light beams opened by a certain angle θ by an optical device 3 provided at a spectral point 2 ahead of one light source 1, and these two light beams are opened. A measurement point 4 located at a location distant from the spectral point 2 by the light beam.
The distance D at h is measured, and the distance D between the spectral point 2 and the measurement point 4 is D = h from the distance h and the angle θ.
A distance measuring method characterized in that it is calculated based on / {2tan (θ / 2)}.