JPH03255910A - Three-dimensional position measurement system - Google Patents

Abstract

PURPOSE:To measure the inside of the hole of an object work to be measured, etc., and to improve the measurement accuracy by measuring the three- dimensional position of an object point to be measured according to a stereoscopic image of the spot light source of a measured object point teaching means. CONSTITUTION:When the three-dimensional position of the measured object point P at the recessed part 4a of the work which can not be picked up directly by TV cameras 1 and 2 is measured, the indication point 6 of a coordinate teaching pen 5 (measured object point teaching means) is brought into contact with the object point P. Consequently, a switch 8 is closed and respective LEDs 7 of the pen 5 illuminate. In this state, the stereoscopic image of the pen 5 including the LEDs 7 is picked up by the cameras 1 and 2. An image processor 3 calculates a three-dimensional position of each LED 7 according to the bright point parallax between the right and left images of the stereoscopic image of the LED 7. Each LED 7 and the indication point are in known fixed position relation, so when the three-dimensional positions of the respective LEDs 7 are known, the fixed position relation is added to the positions to calculate the three-dimensional position of the indication point 6 at the position which can not be picked up by the cameras 1 and 2, i.e. the object point P.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is applicable to computer aided
Design).

CA T (Computer Aided Test
The present invention relates to a three-dimensional position measuring method suitable for inputting the three-dimensional shape and dimensions of a processed product when using a software such as ing), and for use as a man-machine interface with a computer by exchanging three-dimensional information.

[Prior art] This type of three-dimensional position measuring device has been developed by
There is one shown in Publication No. 3-61904. In order to obtain the three-dimensional coordinates of the measurement point on the workpiece surface, this conventional device includes: (1) multiple projectors for projecting bright spots onto the measurement point;
■Two imagers to obtain stereo images around the bright spot; ■Means for calculating the three-dimensional coordinates of multiple measurement points from the stereo images by triangulation; ■From the three-dimensional coordinates of the multiple measurement points. It consists of means for determining the relative positional relationship between the measurement head (projector, imager) and the workpiece. In other words, this conventional device uses a bright spot projected from a light projector to indicate the measurement point on the workpiece surface.

In addition to the above-mentioned conventional technology, a means for directly adding a point light source to a measurement point on the surface of a workpiece is also disclosed [Television Society of Japan Technical Report ITA40-2 (1977) p. 7.
Kurasawa et al.: “Gait pattern measurement system using semiconductor device detection method”].

[Problems to be Solved by the Invention] However, the conventional apparatus that uses a bright spot as a measurement point by irradiation with a light beam has the following problems.

(a) It is impossible to teach parts such as the inside of a hole, the back surface, and the side surface of a workpiece that cannot be seen in common with the left and right imagers.

(b) If the work surface is a mirror surface, no scattered light is generated from the bright spot, making it impossible to capture an image.

(c) If the workpiece surface has low reflectance, an image of a bright spot cannot be obtained.

(d) Even if the surface of the workpiece is a diffusive surface, if the surface is tilted, a bright bright spot will appear on the closer side, causing an error.

(e) If the shape of the workpiece changes drastically, multiple reflections occur, resulting in multiple bright spots.

In addition, with the conventional method of directly adding a point light source to the measurement point, there are problems similar to those in (a), (d), and (e) above, and the position of the point light source is far from the actual surface due to the size of the light source. There are also problems such as a shift of about half, which can cause errors.

The present invention aims to solve such problems,
To provide a three-dimensional position measuring method that enables measurement regardless of whether the inside of a hole, back, side, or surface of a workpiece to be measured is a mirror surface or a diffused surface 9 reflectance, and which improves measurement accuracy. With the goal.

[Means for Solving the Problems] In order to achieve the above object, the three-dimensional position measurement method of the present invention includes at least two imaging devices for obtaining stereo images, and a method based on the stereo images from the imaging devices. comprising a calculating means for calculating a three-dimensional position, a measuring point teaching means having a pointing point indicating a measuring point and a plurality of point light sources having a fixed positional relationship known in advance with respect to the pointing point,
The imaging device images the measurement target point teaching means in a state where the measurement target point is indicated by the pointing point and the plurality of point light sources are turned on, and the calculation means A three-dimensional position of each point light source is calculated based on the stereo image of the light source, a three-dimensional position of the indicated point is calculated based on the obtained three-dimensional position and the fixed positional relationship, and the three-dimensional position is calculated. It is characterized in that it is output as a three-dimensional position of the point to be measured.

[Function] In the three-dimensional position measuring method of the present invention described above, when measuring the three-dimensional position of a point to be measured, the pointing point of the measuring point teaching means is placed in contact with the point to be measured, and this In this state, a plurality of point light sources of the measurement target point teaching means are turned on, and a stereo image of the point light sources is captured by an imaging device.

Then, the calculation means calculates the three-dimensional position of each point light source based on the stereo images of the plurality of point light sources from the imaging device. Here, since the plurality of point light sources and the indicated point have a fixed positional relationship known in advance, once the three-dimensional positions of the plurality of point light sources are known, it is possible to add the fixed positional relationship to the three-dimensional position. , the three-dimensional position of the indicated point can be easily calculated. Since the current stereo image is obtained with the pointing point pointing to the point to be measured, the three-dimensional position of the pointing point remains the three-dimensional position of the point to be measured.

As a result, even if it is not possible to directly capture a stereo image of the measurement target point, if stereo images of multiple point light sources of the measurement target point teaching means are obtained, the three-dimensional position of the measurement target point can be determined from that image. can do.

[Embodiments of the Invention] A three-dimensional position measuring method as an embodiment of the present invention will be explained below with reference to the drawings. Fig. 1 is an explanatory diagram thereof, Fig. 2 is a front view showing the coordinate teaching pen, and Fig. 3 is a drawing. 4 is a circuit diagram showing the circuit configuration of the coordinate teaching pen, and FIG. 4 is an explanatory diagram showing another usage example of the system of this embodiment.

In Fig. 1, 1 and 2 are 2 for obtaining stereo images.
3 is an image processor (calculating means) that calculates a three-dimensional position based on a bright point shift (parallax) in the left and right images of the stereo images from these TV cameras 1 and 2; Reference numeral 4 indicates a workpiece whose position is to be measured, and this workpiece 4 has a concave portion 4a that cannot be imaged by the TV camera 1.2.
have.

Reference numeral 5 denotes a coordinate teaching pen (measuring target point teaching means), and as shown in FIGS. Point 6
Four LEDs (
a point light source) 7, and a switch 8 which becomes a closed circuit state when the pointing point 6 contacts the surface of the workpiece 4 at the tip of the pen 5 including the pointing point 6.

It is composed of a battery 9 that serves as a power source for lighting the LED 7, a glass cover 10 that covers the LED 7, and a protective resistor 11. As shown in FIG. 3, the LEDs 7 are connected in parallel with each other, and when the switch 8 is closed, they receive power from the battery 9 via the protective resistor 11 and turn on. In addition, as shown in FIG.
All ED7 are arranged on the central axis of the coordinate teaching pen 5,
The distance between the indicator point 6 and the lowest LED 7 is Q', and each LED
The distance between 7 and 7 is Ω, which is known in advance. Further, each LED 7 has a footprint angle of 400 μm, for example.

With the above configuration, for example, as shown in FIG.
When measuring the three-dimensional position of the measurement target point P in the recess 4a of the workpiece 4, which cannot be directly imaged by the cameras 1 and 2, first, the coordinate teaching pen 5 is attached to the measurement target point P.
The pointing point 6 of is placed in contact with the point 6 of FIG. Point 6 of coordinate teaching pen 5
is in contact with or pressed against the measurement target point P, the switch 8 is closed and each LED 7 of the coordinate teaching pen 5 is turned on.
lights up.

With each LED 7 lit in this way, the LED
A stereo image of the coordinate teaching pen 5 including 7 is captured by the TV camera 1.
, 2.

The imaging results are input to the image processor 3, and the image processor 3 calculates the three-dimensional position of each LED 7 based on the bright point parallax in the left and right images of the stereo images of the LEDs 7.

Furthermore, since each LED 7 and the pointing point 6 have a fixed positional relationship known in advance as described above with reference to FIG.
Once the three-dimensional position of D7 is known, by adding the fixed positional relationship to that three-dimensional position, the three-dimensional position (three-dimensional coordinate ), that is, the cubic top M of the measurement target point P
(three-dimensional coordinates) can be easily calculated.

By the way, as shown in FIG. 4, the coordinate teaching pen 5 described above can be used as a two-dimensional coordinate input device similar to a conventional digitizer or mouse by moving it in translation on a plane on a desk. In addition, the coordinate teaching pen 5 mentioned above
If the three-dimensional positions of multiple ED7s are obtained using You can also do that. By combining these two types of functions, information such as "three-dimensional coordinates + direction" that matches the human sense of space can be exchanged with a computer, making it possible to effectively use it as a new man-machine interface device.

In this way, according to the measurement method of this embodiment, even if it is not possible to directly capture a stereo image of the measurement target point P,
If a stereo image of each LED 7 of the coordinate teaching pen 5 is obtained, the three-dimensional position of the measurement target point P can be determined from that image. It becomes possible to measure the three-dimensional position of the surface regardless of the magnitude of the surface 2 reflectance, and by increasing the number of LEDs 7, the measurement accuracy can be greatly improved.

Further, the coordinate teaching pen 5 in the measurement method of this embodiment is
As a man-machine interface device with a computer, it can be used as a three-dimensional digitizer device that has a larger amount of one-dimensional information than a two-dimensional digitizer such as a conventional mouse, and in that case, a man-machine interface that is highly compatible with the spatial sense of humans. can be realized.

In the above embodiment, the LED 7 of the coordinate teaching pen 5 is set to 4.
Although the case where LEDs are provided is described, the same function as the above-mentioned embodiment can be obtained if there are at least two LEDs. Furthermore, a large number of LEDs may be arranged to improve the accuracy of detecting coordinates and vectors. Further, in the above embodiment, a case has been described in which the LEDs 7 are arranged in a straight line, but each LED 7 may be arranged in any manner as long as the fixed positional relationship with the pointing point 6 is clear.

Further, in the above embodiment, in order to obtain the three-dimensional position of each point light source, a method is disclosed in which stereo images are captured using two imaging devices and calculations are performed by image processing using an image processor. If two light spot position detectors are used instead of one imaging device, it is also possible to determine the three-dimensional position of each point light source by simple calculations without requiring an image processor. however,
Since the light spot position detector cannot handle multiple point light sources at the same time,
In that case, it is necessary to turn on each point light source in chronological order.

[Effects of the Invention] As detailed above, according to the three-dimensional position measurement method of the present invention, even if it is not possible to directly capture a stereo image of the measurement target point, the point light source of the measurement target point teaching means can be used. By capturing a stereo image, the three-dimensional position of the measurement target point can be measured based on the stereo image. This method has the advantage of being able to perform measurements regardless of the magnitude of the reflectance, and significantly improving measurement accuracy.

[Brief explanation of drawings]

Figures 1 to 4 show a three-dimensional position measurement method as an embodiment of the present invention. Figure 1 is an explanatory diagram thereof, Figure 2 is a front view showing the coordinate teaching pen, and Figure 3 is a diagram showing the coordinates. FIG. 4 is a circuit diagram showing the circuit configuration of the teaching pen, and is an explanatory diagram showing another usage example of the system of this embodiment. In the figure, 1. 2-TV camera (imaging device), 3-image processor (calculating means), 4-workpiece, 4a recess, 5-coordinate teaching pen (measurement target point teaching means), 6-instruction point, 7 −
LED (point light source), 8-switch. 9-Battery, 10-Glass cover, 11-Protection resistor, P-
- A point to be measured.

Claims (1)

[Scope of Claims] At least two imaging devices for obtaining stereo images, and arithmetic means for calculating a three-dimensional position based on the stereo images from the imaging devices, and for indicating a point to be measured. Measurement target point teaching means is provided which has a pointing point and a plurality of point light sources having a fixed positional relationship known in advance with respect to the pointing point, and the measuring point teaching means is provided with a pointing point and a plurality of point light sources having a fixed positional relationship known in advance with respect to the pointing point, and the pointing point is used to point out the measuring point using the pointing point. The measurement target point teaching means in a state where a plurality of point light sources are turned on is imaged by the imaging device, and the calculation means calculates the measurement target point teaching means based on the stereo images of the plurality of point light sources imaged by the imaging device. The three-dimensional position of each point light source is calculated, and the three-dimensional position of the indicated point is calculated based on the obtained three-dimensional position of each point light source and the previously known fixed positional relationship. A three-dimensional position measuring method, characterized in that the three-dimensional position of the designated point is output as the three-dimensional position of the point to be measured.