JPS60177213A - Measuring device for tilt angle - Google Patents

Abstract

PURPOSE:To eliminate the influence of temperature variation by dividing both end positions of an air bubble image by a split projection optical means according to the inclination of an air bubble tube so that both end positions moves in the opposite directions, and forming split images without overlapping. CONSTITUTION:Projection light from a light source 1 consisting of plural light emitting diodes arranged successively is made incident on a diffusing plate 2 and then transmitted light from an air bubble tube 3 is made incident on an alignment prism 4 and projected on a linear image sensor 6 such as CCD through an optical path changing prism 4a and a projection lens 5. The alignment prism 4 is arranged having the center (l) off the center of the air bubble tube 3, and the air bubble image is separated in the lengthwise direction of the linear image sensor 6. Consequently, even if the length of the air bubble is decreased, the interval between tips of the air bubble images is constant.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical understanding of the invention) The present invention relates to an inclination angle measuring device using a bubble tube.

(Background of the Invention) A simple device of this type has a structure in which a bubble image of a tubular level is directly projected onto an image sensor using a projection lens, and the amount of movement of the level is measured on the image sensor. However, in a device with such a simple structure, the bubble length changes due to temperature changes, so the temperature must be measured and corrected separately, making the device complicated. there were.

(Objective of the Invention) An object of the present invention is to provide a tilt angle measuring device with a simple structure that eliminates the influence of changes in bubble length due to temperature changes.

(Embodiment) FIG. 1 is a front view of an embodiment of the present invention, and FIG. 2 is a plan view of a matching prism and an optical path changing prism.

Light emitted from a light source 1 made up of a plurality of light emitting diodes arranged side by side enters a diffuser plate 2, and then transmits and illuminates a tubular vial 3 from the back side. The light transmitted through the tubular bubble tube 3 passes through the matching prism 4
The light passes through the optical path changing prism 4a and the projection lens 5, and is projected onto a one-dimensional image sensor 6 such as a CCI (charge coupled device). The matching prism 4 has its center l
is placed offset from the center of the tubular bubble tube 3, and the offset is sufficient to separate the bubble images in the longitudinal direction of the -dimensional image sensor 6. Actually, since the magnification M of the projection lens 5 is applied, if the interval between the separated bubble images on the -dimensional image sensor 6 is a, the above deviation amount is a
/M.

Because of this structure, when the inclination of the tubular bubble tube 3 is zero, the peripheral area shown by the solid line in FIG. bubble image 7
a and 7b occur. The distance between the tips of the bubble images 7a, 71) is a. Even if the bubble length expands or contracts due to temperature changes, the distance a between the tips of the bubble images 7a and 7b remains constant. That is,
Even if one bubble image 7a shrinks by Δa as shown by the broken line,
The other bubble image 7b also shrinks by Δa as shown by the broken line, so
The spacing between the tips does not change.

When the tubular bubble tube 3 is tilted, the distance between the bubble images 7a and 7b changes as shown by the broken line in FIG.

If this interval is X, the inclination θ of the tubular vial 3 is -2-
f depends on m=. Now, set the sensitivity of the tubular vial 3 to P seconds/
If 2 mm, 1x-a on image sensor 6
, t' 2 2M (1).

Therefore, as shown in FIGS. 5 and 6, the waveform shaping circuit 9 converts the video signal as indicated by the dotted line in FIG. level V. The pulse generation circuit 10 obtains a pulse generated at the rising edge of the rectangular signal as shown in FIG. 6(C), and the pulse interval measuring circuit 11 generates a rectangular signal as shown in FIG. If we calculate the pulse interval corresponding to the interval between the bubble images 7a and 7b, we can obtain the values a and P in advance.
.

As explained in FIG. 3, even in this case, the interval X does not change even if there is a temperature change.

In addition, the above-mentioned device can automatically correct errors caused by the tilt K of heavy equipment by incorporating it into a device such as a digital theodolite that generates electrical signals from vertical and horizontal angles. . .

It should be noted that it is effective to use the above-mentioned device as a leveling inclinometer, since the inclination angle can be measured from any point.

(Effects of the Invention) As described above, according to the present invention, it is possible to obtain an inclination angle measuring device that can easily and automatically measure an inclination angle without being affected by temperature changes.

[Brief explanation of drawings]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is a plan view of the matching prism and optical path changing prism shown in FIG. 1, and FIG. 3 is a diagram showing that there is no influence of temperature changes. Figure 4 shows the bubble image on the -dimensional image sensor to explain that the position of the bubble changes depending on the tilt of the bubble tube. FIG. 5 is a processing block diagram of an embodiment of the present invention, and FIG. 6 is a waveform diagram of each part of FIG. (Explanation of symbols of main parts) 3. Tubular bubble tube, 4. Matching prism, 4a. Optical path changing prism, 5. Projection lens, 6. -Dimensional image sensor. '! 'II', +1 applicant Takao Watanabe, agent of Nippon Kogaku Kogyo Co., Ltd.

Claims (1)

[Claims] It has a tubular bubble tube, a -dimensional image sensor, and a division projection optical means for dividing a bubble image of the bubble tube and forming it on the image sensor, and the division projection optical means comprises:
An inclination angle characterized in that the bubble image is divided such that both end positions of the bubble image move in opposite directions depending on the inclination of the bubble tube, and the divided images are formed so that the divided images do not overlap. measuring device.