JP2977102B2 - Position measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position measuring device for measuring three-dimensional coordinates of a plurality of measuring points.

[0002]

2. Description of the Related Art Conventionally, a plurality of points (measurement points) on an object to be measured have been used in order to recognize the surface shape and the like of the object to be measured.
Various position measuring devices for measuring three-dimensional coordinates have been proposed. In one of such devices, a retro-reflector which previously reflects light at a plurality of measurement points in a direction exactly opposite to the incident direction is arranged, and the plurality of retro-reflectors are irradiated with laser light, and the reflected light There is a device that receives the light and obtains the retroreflector, that is, the three-dimensional coordinates of each measurement point.

FIG. 2 shows an example of the conventional position measuring device. In the drawing, reference numeral 1 denotes a measuring point, 2 denotes a pulse laser light source,
3 is an optical system, 4 is a streak tube, 5 is a reference optical fiber,
Reference numeral 6 denotes a synchronization unit, 7 denotes a time delay adjustment circuit, 8 denotes a voltage application suppression circuit, and 9 denotes an image processing device.

The measuring points 1 are a plurality of points on the object to be measured (not shown), and retroreflectors for reflecting light in the direction exactly opposite to the incident direction are arranged in advance.
The pulse laser light source 2 generates a pulse laser light having a constant period. The optical system 3 divides the pulse laser light emitted from the pulse laser light source 2 into two, irradiates one of them into a plurality of measurement points 1 and guides the reflected light to the streak tube 4,
The other is guided to the streak tube 4 via a reference optical fiber 5 having a fixed length, that is, a fixed optical path length (hereinafter, referred to as a reference optical path length). The optical system 3
Is composed of convex lenses 10, 11, and 12, a concave lens 13 for diffusing pulse laser light, and a half mirror 14.

The streak tube 4 has a light receiving surface 4a and a fluorescent surface 4a.
The light incident on the light receiving surface 4a is photoelectrically converted into electrons, and flies to the fluorescent surface 4b to generate a bright spot. At this time, by applying a sweep voltage from the outside perpendicularly to the flight direction of the electrons and at the same timing, the flight direction of the electrons can be deflected,
The luminescent spot moves on the phosphor screen 4b in proportion to the amount of deflection.
The application of the sweep voltage is possible by knowing the timing at which the pulsed laser light is emitted and adjusting the time delay by an electric circuit, and is realized by the synchronization unit 6 and the time delay adjusting circuit 7.

In the streak tube 4, the voltage for deflecting the electrons is an AC sawtooth voltage having a much longer period than the period of the pulsed laser light emitted in a short period. 8 is applied.

That is, at the time of voltage suppression, as shown in FIG.
The luminescent spot 16 caused by the laser beam 5 passing through the reference optical fiber 5 is projected on the fluorescent screen 4 b of the streak tube 4 while maintaining the relationship with the optical axis of the optical system 3. The angle with respect to the device position of No. 1 is known.

When a voltage is applied, the bright spot 1
Reference numeral 5 denotes a difference in arrival time at the streak tube 4 between the laser light reflected at the measurement point 1 and the laser light passing through the reference optical fiber 5 as shown in FIG. Moves a distance proportional to the difference from the length of the fiber 5,
The image is displayed as a bright point 15 '. The bright spot 16 does not move. However, since the bright spot 16 does not move even when a sweep voltage is applied, the bright spot 16 is moved to the bright spot 16 because the length of the reference optical fiber 5 is used as the reference optical path length. The time of the sweep voltage by the time delay adjustment circuit 7 is set in advance so that the time when the corresponding electron passes through the deflection unit (not shown) of the streak tube 4 and the time when the sweep voltage crosses 0 [V] coincide. This is due to adjusting the delay.

The luminescent spot 15-15 on the fluorescent screen 4b
Image processing device 9 using CCD camera
The image is analyzed and the relative distance to the length of the reference optical fiber 5 is calculated. By adding this relative distance and the length of the reference optical fiber 5, the absolute distance to the measurement point 1 can be determined. As described above, the two pieces of angle information of the measurement point 1 can be measured when the voltage is suppressed, and the distance information can be measured when the voltage is applied, whereby the three-dimensional coordinates of the measurement point 1 can be measured.

[0010]

The measurement of the three-dimensional coordinates of the measuring point 1 in the above-mentioned apparatus is performed sequentially in two stages of application and suppression of the sweep voltage to the streak tube 4, from which the angle information and the distance information are obtained. Thus, the three-dimensional coordinates of the measurement point 1 are obtained.

However, the time required for switching between the application of the sweep voltage and the suppression is limited by the time constant of the voltage application suppression circuit 8, and there is a problem that the measurement time cannot be shortened beyond these limits. .

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a position measuring device capable of measuring three-dimensional coordinates of a measuring point at high speed.

[0013]

In order to achieve the above-mentioned object, the present invention has an optical fiber bundle in which a plurality of optical fibers are divided into two in the middle and bundled, and one image is divided into two identical images. In addition to using the obtained optical system, a sweep voltage was constantly applied to the streak tube, and a branched image was photographed by another image processing device and analyzed.

[0014]

According to the present invention, the same image as in the case where no sweep voltage is applied to the streak tube by the optical system can be branched, and this image is taken by another image processing apparatus and analyzed to obtain a measurement point. Is obtained. Further, by constantly applying the sweep voltage to the streak tube, distance information of the measurement points can be obtained at the same time, and the measurement time can be reduced.

[0015]

FIG. 1 shows an embodiment of a position measuring apparatus according to the present invention. In the figure, the same components as those of the conventional example are denoted by the same reference numerals. That is, 1 is a measurement point, 2 is a pulse laser light source,
4 is a streak tube, 5 is a reference optical fiber, 6 is a synchronization unit, 7 is a time delay adjustment circuit, 9 and 21 are image processing devices, 22 is an optical system, and 23 is an electronic computer.

The optical system 22 comprises an optical fiber coupler 24, an optical fiber bundle 25, lens systems 26, 27, 28, optical fibers 29, 30, 31, and a concave lens 32.

The optical fiber coupler 24 comprises two optical fiber couplers 24a and 24b as shown in FIG. 4. The optical fiber coupler 24a splits the laser light emitted from the pulse laser light source 2 into two, One of them enters the reference optical fiber 5 and the other enters the optical fiber 2.
9 is incident. The optical fiber coupler 24b enters the reference optical fiber 5 and splits the laser light returning via the reference optical fiber 5 into two light beams, which are respectively input to the optical fibers 30 and 31.

The optical fiber bundle 25 comprises a main body 25-1 formed by bundling a plurality of optical fibers without any gap and forming a substantially circular section.
It is composed of branch portions 25-2 and 25-3 formed by bundling half of the optical fibers of the plurality of optical fibers constituting the main body portion 25-1 without gaps and forming a substantially circular cross section.

FIG. 5 shows the optical fibers constituting the branching portions 25-2 and 25-3 among the optical fibers constituting the main body 25-1. In the drawing, reference numeral 25a denotes the branching portion 25-2. 25b is an optical fiber constituting the branching section 25-3. The optical fibers 25a and 25
“b” is two-dimensionally arranged alternately in the cross section (end face) of the main body 25-1, and their relative positions are also determined in the cross section (end face) of the branch portions 25-2 and 25-3. It is arranged so as not to change. Therefore, the image input from the end face of the main body 25-1 is transmitted to the branch 25-.
2 and 25-3 are output as they are (although the image quality is slightly reduced).

The optical fiber 29 is disposed substantially at the center of the main body 25-1.
The optical fibers 30 and 31 are disposed at substantially the center positions of the optical fibers 30 and 25-3, respectively.

The lens system 26 couples the end face of the main body 25-1 of the optical fiber bundle 25 to the concave lens 32, and the lens systems 27 and 28 form the branching portion 25- of the optical fiber bundle 25.
2 and 25-3, and light receiving surface 4a of streak tube 4
And the image pickup surface of the image processing device 21.

In the above apparatus, the laser light emitted from the pulse laser light source 2 is split into two by an optical fiber coupler 24a, one of which is incident on a reference optical fiber 5,
The other is incident on the optical fiber 29. The laser light incident on the reference optical fiber 5 reciprocates through the reference optical fiber 5 and is incident on the optical fiber coupler 24b, where it is split into two and incident on the optical fibers 30 and 31. The laser beam incident on the optical fiber 29 is applied to the measurement point 1 from substantially the center of the main body 25-1 of the optical fiber bundle 25 via the lens system 26 and the concave lens 32.

At this time, the laser beam reflected at the measurement point 1 is transmitted through the concave lens 32 and the lens system 26 to the optical fiber bundle 2.
5 is incident on the main body 25-1. The laser beam (image by the laser beam) incident on the main body 25-1 is branched to the branch portions 25-2 and 25-3 as described above, and the laser beam branched to the branch portion 25-2 is light. The laser beam, which is incident from the fiber 30 and passes through the reference optical fiber 5, is guided to the streak tube 4 via the lens system 27, and the laser beam branched to the branch portion 25-3 is incident from the optical fiber 31. The image processing device 2 via the lens system 28 together with the laser beam passing through the reference optical fiber 5
It is led to 1.

A sweep voltage is always applied to the streak tube 4 by the synchronization unit 6 and the time delay adjusting circuit 7 in consideration of the emission timing of the pulsed laser light, the delay of the electric circuit, and the like. As in the case of (1), the distance information of the measurement point 1 can be obtained by taking an image with the image processing device 9 and analyzing the image. On the other hand, the laser light (image by) incident on the image processing device 21 is similar to the case where the sweep voltage is not applied to the streak tube 4, so that the image is captured by the image processing device 21 and the image is analyzed to obtain the measurement point 1 Is obtained. These two image processing devices 9,
The three-dimensional coordinates of the measurement point 1 are obtained by the calculation by the electronic computer 23 using the distance and angle information from 21.

As described above, according to the apparatus, distance information and angle information of a measurement point can be obtained at the same time, and there is no need to switch between application and suppression of the sweep voltage to the streak tube. The three-dimensional coordinates of a point can be measured at high speed. In addition, the voltage application suppression circuit becomes unnecessary,
Problems associated with the switching, such as noise and circuit stability, can be avoided. In addition, it is not necessary to set an optical system using a half mirror or the like, and the operability is good. Furthermore, by increasing the length of the optical fiber constituting the optical fiber bundle, the optical system can be easily separated from the streak tube and the image processing apparatus. It is suitable for a configuration in which only the circuit is exposed to the outer space, and the processing circuit and the like are put in the body of the satellite for protection.

[0026]

As described above, according to the present invention, distance information and angle information of a measurement point can be obtained at the same time, and there is no need to switch between applying and suppressing the sweep voltage to the streak tube. The measurement can be shortened, and the three-dimensional coordinates of the measurement point can be measured at high speed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a position measuring device according to the present invention.

FIG. 2 is a configuration diagram showing an example of a conventional position measuring device.

FIG. 3 is an explanatory diagram showing an example of a bright spot displayed on a phosphor screen of a streak tube when voltage is suppressed and when voltage is applied.

FIG. 4 is a detailed explanatory view of an optical system in the apparatus of FIG. 1;

FIG. 5 is a cross-sectional view taken along line AA of FIG. 4;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 measurement point 2 pulse laser light source 4 streak tube 4 b fluorescent screen 5 reference optical fiber 6 synchronization unit 7 time delay adjustment circuit 9, 21 image processing device 22 optics System, 23: Computer, 24: Optical fiber coupler, 25: Optical fiber bundle, 26, 27, 28: Lens system, 29, 30, 31: Optical fiber, 32: Concave lens.

Claims (1)

(57) [Claims] 1. A pulse laser light source for generating a pulse laser beam, a streak tube having a fluorescent screen for generating a bright spot corresponding to the incident light, a light emission timing of the pulse laser beam,
A means for constantly applying a sweep voltage taking into account the delay of the air circuit, etc.
And a reference optical path having a constant optical path length, and a plurality of optical fibers bundled without any gap at one end, and the other end
On the side, half of them are bundled without gaps,
The relative position of each optical fiber at the two other ends is
The image input from the
The optical fiber bundle has an optical fiber bundle arranged so as to be output, divides a pulse laser beam emitted from a pulse laser light source into two, irradiates one to a plurality of measurement points, and reflects the reflected light to the optical fiber. incident on one end of the bundle and the other is through the reference optical path, two of said optical fiber bundle is divided further into two
Respectively incident on the other end of an optical system for guiding one of the other end of the optical fiber bundle in the streak tube, the phosphor screen and each photographed image analysis the other end of the other one of the optical fiber bundle of the streak tube A position measuring device comprising a pair of image processing devices.