JPH04203906A - Measuring apparatus of position - Google Patents

Abstract

PURPOSE:To enable execution of measurement with the precision equivalent to the length of a pixel or to the one less than that even when an image is sensed over a number of pixels and thereby to improve the precision in measurement by using a light-emitting body which emits light with luminous intensity being in a known distribution for all directions. CONSTITUTION:A light-emitting body 5 of which the luminous intensity is in a Gaussian distribution being usable conveniently relatively, out of known luminous intensity distributions for all directions, is employed. Besides, two photosensors 3a and 3b are disposed at arbitrary different positions Pa and Pb and mounted on bases in such a manner that the angles thereof can be varied in vertical and horizontal directions manually or automatically so that light can be sensed even when the body 5 moves to a position being different to a large extent. The angles formed when the sensors are operated manually or automatically so that the light of the body 5 is sensed at the centers of the image-sensing screens thereof, for instance, are outputted to an arithmetic processing device 20 through angle detecting devices attached to the sensors 3a and 3b. In the device 20, the position P1 of the body 5 is calculated from position coordinates Pa (Xa, Ya, Za) and Pb (Xb, Yb, Zb) by prescribed operations. According to this constitution, the precision in measurement of the position of the body 5 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a position measuring device that uses a light emitter to measure the position of the light emitter.

[Prior art] In order to measure the finished precision of a processed workpiece,
It is necessary to measure the position of a specific point. Conventionally, as a method of measuring the position of the light emitter using a light emitter and performing processing such as predetermined calculations, there is a method of measuring the position of the light emitter using a light emitter 5 and two light receivers as shown in FIG. This was done using vessels 3a and 3b.

That is, an LED or the like is placed as the light emitter 5 at the measuring point P1, and CCD cameras are used as the light receivers 3a and 3b.
The angle between the light emitting body 5 and each CCD camera 3a13b (zenith angle α
, horizontal angle β) is detected by the angle detection device attached to the receiver,
Similarly, an arithmetic processing unit 20 attached to the light receiver performs a predetermined calculation based on the angle and the position coordinates of the light receivers 3a and 3b to calculate the position of the light emitter 5. Furthermore, the target position whose positional relationship with the light emitter 5 is known is also calculated as a measurement result.

[Problems to be Solved by the Invention] The above method for measuring the position of the light emitting source has the following problems. That is, as the light receivers 3a and 3b, for example, CCD
When using a camera, the image receiving screen of a CCD camera has a finite number of pixels arrayed with a specific length in both the vertical and horizontal directions, and even if the light from the light emitter is captured by the CCD camera, it will be smaller than the length of the pixel. It cannot be measured with precision. That is, as a result of the received light being received across a large number of pixels, the positional relationship between the position of the light emitter and the image receiving screen becomes unclear, making it difficult to improve measurement accuracy.

[Means for Solving the Problems] A position measuring device of the present invention includes two or more light receivers that receive light from a light emitter, and an arithmetic device that uses the light receivers to calculate the position of the light emitter. , a light emitting body is used whose luminous intensity has a known luminous intensity distribution in all directions.

[Operation] A luminous body that emits light with a known luminous intensity distribution in all directions is used. Therefore, when light from a light emitter is received by a CCD camera, even if the image is received over many pixels, since the luminous intensity distribution of the light emitter is known, it can be measured with an accuracy less than the length of the pixel. It is possible to improve measurement accuracy compared to .

[Example code] An embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows a light emitter placed at a measuring point P1 on a workpiece 1 in order to measure the accuracy of the surface of a workpiece 1 processed in the same manner as in the conventional example.
FIG. 4 is a conceptual diagram for calculating the position coordinates of the light emitting body 5 by placing the light emitting body 5 on the light emitting body 5. The light emitting body 5 used in this embodiment is one having a Gaussian distribution, which is relatively easy to use, among those having a known luminous intensity distribution in all directions. on the other hand,
Two light receivers (CCD cameras are used in this example) 3a
13b are arranged at arbitrary different positions Pa and Pb. The light receivers 3a, 3b are mounted on a base (not shown) so that the angle can be changed manually or automatically in up, down, left and right directions so that even if the light emitting body 5 moves to a greatly different position, it can receive light. In addition, the angles (zenith angles α11, α21, horizontal angles β11, β21) when the light from the light emitting body 5 is manually or automatically operated to receive the image at the center of the screen, for example, are the angles (zenith angles α11, α21, horizontal angles β11, β21) of the light receiver 3a (not shown). , 3b are outputted to the arithmetic processing unit 20 via the attached angle detection device. The arithmetic processing unit 20 calculates the angle and the position coordinates Pa (Xa) of the light receivers 3a and 3b.

The position P1 of the light emitter 5 is calculated by performing a predetermined calculation from Ya, Za) and Pb (Xb, Yb, Zb).

That is, specifically, it is calculated as follows. The light emitter 5 is placed on the measurement point P1 on the workpiece 1, and the light from the light emitter 5 is received by the light receivers 3a and 3b. Receiver (CCD camera)
As shown in FIG. 2, the image receiving screens 11 of 3a and 3b are composed of pixels 10 arranged vertically and horizontally (the length is a by vertical and horizontal is b),
The angles of the light receivers 3a and 3b are adjusted so that the light receivers 3a and 3b receive light at the center of the image receiving screen 11 (the intersection of the pixels indicated by lines m and n). However, depending on the type of the light emitting body 5, the image may be received across a plurality of pixels 10 as shown in the shaded area in FIG. becomes unclear,
It is difficult to measure the position of the light emitter 5 with an accuracy less than the length of the pixel 10. That is, since the luminous intensity distribution of the light emitter 5 is unknown, the luminous intensity distribution on the image receiving screen 11 differs depending on the positions and angles of the light receivers 3a and 3b. Therefore, even if the center of the image receiving screen 11 (the intersection on the pixels indicated by the line mSn)
Even if the angles of the light receivers 2a and 2b are adjusted so that the light is received at 1, the adjusted angles are inaccurate.

However, when using the light emitting body 5 that emits light with a Gaussian distribution in all directions used in this embodiment, the received light intensity also varies between the centers m and n of the image receiving screen 11, as shown in FIG. It becomes a Gaussian distribution with a peak at
Images are received regardless of the positions and angles of a and 3b. For that reason,
The light received by the light emitter 5 is placed at the center of the image receiving screen 11 (the intersection of mSn).
The angles (zenith angles α11, α21, horizontal angles β11, β21) when each light receiver 3a, 3b is activated are detected by the angle detection device, and the light emitting body 5 is detected by the arithmetic processing device 20 in the following manner. The position P1 can be determined and will be explained with reference to FIG.

The positions of the light receivers 3a, 3b, etc. in the space represented by the x, y, and z axes are as follows. Fixed receivers 3a, 3b
The position coordinates of Pa (Xa, Ya.

Za), Pb (Xb, Yb, Zb), and the position coordinates of the light emitter 5 are determined as PL (Xi, Yl, Zl), and the coordinates PL (Xi, Yl, Zl) of the light emitter 5 are determined.

The light receivers 3a and 3b are operated to receive the light from the light emitter 5, for example, at the center m1n of the image receiving screen 11 of the light receivers 3a and 3b, and the determined zenith angles of the light receivers 3a and 3b are α11, α21, Let the horizontal angles be β11 and β21. or,
The distance between Pa and 21 is Lla, and the distance between Pb and Pl is Ll.
b, zenith angle α11, α21, horizontal angle β11, β21, X1=Xa −Lla −8IN (all) ・CO8(β11)
Y 1 = Y a −Lla −8IN (all) ・S IN (β1
1) Z1=Za+L1a -CO8(all)X1=X
b -Llb-3IN(α21)・CO8(β21)Y1=
Yb-Llb-8IN(α21)・5IN(β21)Z1
The relational expression =Zb+L1b-CO8(α21) is established.

From the above formulas, the coordinates PL of the light emitter 5 (Xi, Yl,
Zl) can be found.

In the above embodiment, two light receivers were used, but if a large number of light receivers are installed, measurement can be performed without moving the light receivers by selecting the light receiver corresponding to the shape of the workpiece. In addition, the angle of the light receiver was simply determined by receiving the light from the emitter so that it was centered on the image receiving screen of the light receiver, but it is also possible to receive the light at any position on the image receiving screen and perform calculation processing to calculate the angle. It may be calculated. In addition, when using another light emitter whose luminous intensity distribution is known, the exact position of the emitter can be determined by calculating the angle of the receiver by calculating from the received luminous intensity distribution and the known luminous intensity distribution. It can be calculated.

Further, in the above embodiment, a CCD camera was used as a light receiver, but an MO3 type image receiving element formed of similar pixels may also be used. Furthermore, the same holds true even when using a camera that uses scanning lines to image on a monitor.

[Effects of the Invention] Since the position measuring device of the present invention uses a light emitter whose luminous intensity distribution is known in all directions, image reception is independent of the position of the light emitter, which improves the accuracy of position measurement of the light emitter. You can improve your performance.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention. Fig. 1 is a conceptual diagram of a position measuring device, Fig. 2 is a diagram showing a part of the image receiving screen of a light receiver, and Fig. 3 is a diagram showing the received light intensity on a pixel. FIG. 1... Workpieces 3a, 3b... Light receivers Pa, Pb... Coordinates of the light receiver 5... Light emitter Pl... Coordinates of the light emitter α11, α21... Zenith angle β11, β21...・Horizontal angle

Claims (1)

[Scope of Claims] In a position measuring device comprising two or more light receivers that receive light from a light emitter, and an arithmetic device that uses the light receivers to calculate the position of the light emitter, the luminous intensity of the light emitter is determined by: A position measuring device characterized in that it uses a light emitter that has a known luminous intensity distribution in all directions.