JPH04250384A - Three-dimensional target identification device - Google Patents

Abstract

PURPOSE:To accurately identify a target even when the wavelength of an electromagnetic wave is longer than the target by measuring the reflecting electromagnetic wave from the target at a plurality of measurement points, and by examining the intensity distribution of the reflecting electromagnetic wave of the target from the center to the edge. CONSTITUTION:A pulse of predetermined number is sent to an antenna scanner 22 by a microcomputer 28, and transmission and input antennae 21a, 21b are moved to predetermined measurement points, and the digital information indicating the intensity of the reflecting electromagnetic wave is stored from the output of an A/D converter 27. When the storage of the digital information is finished at all of the measurement points, a maximum value of the reflecting intensity is found out, and position coordinates (x,y) of the antennae 21a, 21b on that point are searched. A coordinate (x) is fixed, while a coordinate (y) is varied, so as to examine the intensity distribution at each measurement point, and it is judged if the intensity distribution is diminished in a simple mode. When it is not, a target is considered to have a curvature in the back surface, and an H signal is output to a line 30. When it is judged as simply diminishing, the coordinate (y) is fixed, and the same operation is carried out.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to a three-dimensional object marker identification device for identifying a target object using information on the reflection intensity of electromagnetic waves, and in particular to a device for detecting whether or not a target object has a curvature on its back surface. This invention relates to a device for identifying three-dimensional objects.

0002

2. Description of the Related Art FIG. 7 shows an example of a conventional object marker identification device for identifying targets using information on the reflection intensity of electromagnetic waves.

In FIG. 7, the antenna 1 is placed in the horizontal direction (X
The transmitting antenna 1a and the receiving antenna 1b are arranged in the antenna moving table 2. As shown in FIG. 8, the antenna moving table 2 has a transmitting antenna 1a and a receiving antenna 1b set between a start point S and an end point E in the X-Z plane on the antenna moving table 2. It can be moved to multiple measurement points.

[0004] The transmitting antenna 1a has, for example, a 60GH
The output of a Gunn oscillator 3 that oscillates electromagnetic waves in the millimeter wave band z is connected via a millimeter wave cable 4, and from this transmitting antenna 1a, electromagnetic waves of 60 GHz are transmitted forward with a spread angle of 4 degrees, for example.

[0005] The receiving antenna 1b receives the 60GH signal transmitted from the transmitting antenna 1a and reflected by the target object 5 in front.
The reflected electromagnetic wave of z is received at each measurement point. In addition, in FIG. 7, a spherical object disposed on a table 6 is shown as the target object 5.

The output of the receiving antenna 1b is applied to a spectrum analyzer 8 via a millimeter wave cable 7. The spectrum analyzer 8 measures the intensity of reflected electromagnetic waves at each measurement point from the target object 5 in front of the output of the receiving antenna 1b.

The microcomputer 10 receives the intensity of the reflected electromagnetic waves at each measurement point measured by the spectrum analyzer 8 via the interface bus (GP-IB) 9, and calculates the intensity of the reflected electromagnetic waves at each measurement point. It is classified into a plurality of level ranges, and each level range is associated with a plurality of gradations of, for example, a single color, and the intensity of the reflected electromagnetic waves at each measurement point is colored. A signal obtained by coloring the intensity of the reflected electromagnetic waves at each measurement point is sent to the monitor display 11, and the intensity of the reflected electromagnetic waves at each measurement point is displayed, for example, in a plurality of gradations of a single color.

The operation of this conventional device will be further explained with reference to the flowchart of FIG.

First, the spectrum analyzer 8 is initialized from the microcomputer 10 via the interface bus (CP-IP) 9, and a command is sent to the antenna moving base 2 to initialize the antenna moving base 2 (step 101).

Next, the transmitting antenna 1a and the receiving antenna 1b are moved to the starting point S (step 10).
2). Here, the intensity of the reflected electromagnetic waves at this time is measured by the spectrum analyzer 8 (step 103),
This measurement data is transmitted to the microcomputer 10 (step 104).

Next, the microcomputer 10 drives the antenna moving table 2 to move the transmitting antenna 1a and the receiving antenna 1b to the next measurement point (step 10).
5).

Next, it is checked whether the antenna moving table 2 is at the end point E (step 106), and if it is not the end point E, the process returns to step 103, and this operation is continued until the antenna moving table 2 reaches the end point E. repeat. In this way, the data of all measurement points from the start point to the end point are loaded into the microcomputer 10.

When the antenna moving base 2 reaches the end point E, the microcomputer 10 detects the minimum received strength and the maximum received strength from the measured values at each measurement point (step 107), and calculates the difference between the minimum received strength and the maximum received strength. For example, the area is divided into 9 parts, and the received strength at each measurement point is checked to see which category from 1 to 9 it belongs to, and the received strength at each measurement point is labeled with a numerical value from 1 to 9 (step 10).
8) From the measurement point of maximum reception strength (point belonging to classification "1") to the measurement point of minimum reception strength (point belonging to classification "9"), gradation is done in a single color corresponding to reception strength. The images are colored differently, and this is converted into an image on the monitor display 11 (step 109).

[0014]

[Problems to be Solved by the Invention] However, in the conventional device that monitors and displays the reception intensity at multiple points from the target object in front using gradation, it is difficult to detect a target object whose electromagnetic wave projection area is approximately equal (for example, In cases where the wavelength of the electromagnetic waves used for measurement is large compared to the size of the target object (a square plate and a sphere with approximately equal cross-sectional area), the edge of the target object in the monitor image can be determined based on its resolution. sometimes became unclear and it was not possible to distinguish between the two. For example, if this device were to be used as a visual sensor for a robot, it would be impossible to distinguish between a square plate and a cylinder.
In this case, there was a problem that it led to errors in the work and the work could not be done accurately.

[0015] Therefore, the present invention provides a three-dimensional method that can accurately identify a target object even when the projected area of the electromagnetic waves is equal and the wavelength of the electromagnetic wave used for measurement is large compared to the size of the target object. The purpose is to provide an original identification device.

[0016]

[Means for Solving the Problems] In order to achieve the above object, the present invention has an electromagnetic wave transmitting/receiving means a configured as shown in FIG. , reflection intensity distribution measuring means b for measuring the distribution of the reflection intensity from the center to the edge of the target;
and back surface shape determining means (c) for determining that the back surface of the target object does not have curvature when the distribution of reflection intensity measured by the measuring means (b) monotonically decreases from the center to the edge of the target object. There is.

[0017]

[Operation] Measure the reflection intensity at multiple points, and if the distribution of reflection intensity monotonically decreases from the center to the edge of the target, it is determined that the back surface of the target has no curvature. Distinguish and recognize cases where the back shape of the back surface is different.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the drawings.

First, the principle of detecting a target according to the present invention will be explained. A ball with a diameter of 200 mm and a ball with a diameter of 150 mm are used as targets.
Let us consider a case where a flat plate of 150 mm is identified using the conventional apparatus shown in FIG. Here, the electromagnetic wave projected from the transmitting antenna 1a in FIG. 7 to the target object 5 is 60GH.
Let's assume a millimeter wave of z (wavelength 5 mm), and its spread angle is 4 degrees,
The distance from the transmitting antenna 1a to the target object 5 is 2 m, and the scanning range of the transmitting antenna 1a, that is, the movement range of the transmitting antenna 1a and the receiving antenna 1b in FIG. 8 is 300 mm in the horizontal direction and 300 mm in the vertical direction. . In this case, as already mentioned, in the conventional device shown in FIG. 7, there is no significant difference in the monitor image on the monitor display 11, and the sphere and the flat plate cannot be distinguished from the monitor image on the monitor display 11.

However, when the intensity distribution of the reflected electromagnetic waves from the target object 5 is examined in detail, a remarkable difference is recognized between when the target object 5 is a sphere and when it is a flat plate.

FIGS. 5A and 5B show the intensity distribution of reflected electromagnetic waves when the target object 5 is a sphere and a flat plate, respectively. In FIGS. 5(a) and 5(b), the two axes of the x-y plane indicate position coordinates, and the z-axis indicates the intensity of reflected electromagnetic waves. As is clear from Fig. 5(b), when the target is a flat plate, the intensity of the reflected electromagnetic wave decreases monotonically no matter which direction the position coordinate is moved from the point where the intensity of the reflected electromagnetic wave is maximum. , it shows a so-called unimodal distribution, whereas when the target is a sphere, as shown in the same figure (c), there is a slight increase or decrease in the intensity distribution of the reflected electromagnetic waves, resulting in a unimodal distribution. It can be seen that it does not show This can be explained by the so-called creeping wave phenomenon.

FIGS. 6(a), (b), and (c) are for explaining this creeping wave phenomenon. For example, if the target object 5 is a sphere as shown in FIG. 6(a), the rear part of the target object 5 has a curvature in this case, so the position of the target object 5 and the antenna 1 shown in FIG. 6(a) is In this relationship, the electromagnetic waves received by the antenna 1 include a wave that is directly reflected from the target object and a wave that comes around from the rear of the target object along the spherical surface of the target object 5. This is the creeping wave phenomenon. In this case, the waves directly reflected from the target object 5 and the waves coming around from the rear of the target object may interfere, and the electromagnetic waves received by the antenna 1 may be strengthened or weakened by each other.

Furthermore, in the positional relationship between the target object 5 and the antenna 1 shown in FIG. Although there should be no reflected electromagnetic waves from the target object 5, there are cases where waves coming around from the rear of the target object 5 occur and become electromagnetic waves received by the antenna 1.

On the other hand, if the target object 5 is a flat plate as shown in FIG. 6(c), the creeping wave phenomenon due to the wraparound of waves as described above does not occur.

Therefore, when the target is a flat plate, the intensity of the reflected electromagnetic waves decreases monotonically no matter which direction the position coordinates are moved from the point where the intensity of the reflected electromagnetic waves is maximum.
In contrast, when the target object is a sphere with a curvature on its back surface, the intensity distribution of reflected electromagnetic waves increases and decreases in a complex manner, and does not show a unimodal distribution.

The present invention pays attention to the above phenomenon and distinguishes between a target object such as a sphere having a curvature on its back surface and a target object such as a flat plate having no curvature on its back surface.

FIG. 2 shows an embodiment of the present invention. FIG. 2 corresponds to the conventional device shown in FIG. 7, and this figure is a top view of the device corresponding to FIG. In this embodiment, in order to reduce the size of the spectrum, the spectrum analyzer 8 shown in FIG. 7 is replaced by a detector 26 that outputs a voltage signal corresponding to the magnitude of the input electromagnetic wave.
The detector 26 and the analog/digital converter 2 are configured using an analog/digital converter (A/D converter) 27 that converts the output of the
7 may be constructed from a spectrum analyzer as in the conventional example shown in FIG. Furthermore, in the conventional example shown in FIG. 7, an antenna scanner movable in the X-Z direction is assumed as the antenna moving table 2, but in the embodiment shown in FIG. The antenna scanner 22 is composed of a combination of two uniaxial scanners: an X-axis scanner and a Z-axis scanner movable in the Z-axis direction. This antenna scanner 22 can also be replaced with an antenna moving table similar to that shown in FIG.

First, to explain the configuration, in FIG.
The antenna 21 consists of a transmitting antenna 21a and a receiving antenna 21b arranged in the horizontal direction (X direction),
This transmitting antenna 21a and receiving antenna 21b
is arranged in the antenna scanner 22.

The antenna scanner 22 consists of a combination of two uniaxial scanners, an X-axis scanner movable in the X-axis direction and a Z-axis scanner movable in the Z-axis direction. As shown in FIG. 3, the transmitting antenna 21a and the receiving antenna 21b are
It is configured to be able to move to a total of 900 measurement points, including 30 points in the Z-axis direction. The movement of the transmitting antenna 21a and the receiving antenna 21b by the antenna scanner 22 is controlled by a microcomputer 28, which will be described later.

[0030] The transmitting antenna 21a has, for example, a 60G
The output of a Gunn oscillator 23 that oscillates electromagnetic waves in the millimeter wave band of Hz is connected via a millimeter wave cable 24, and this transmitting antenna 21a has a spread angle of 4 degrees and a 60G beam forward.
Sends out Hz electromagnetic waves.

The receiving antenna 21b receives at each measurement point the 60 GHz reflected electromagnetic wave that is transmitted from the transmitting antenna 21a and reflected by a target (not shown) in front.

The output of the receiving antenna 21b is input to the wave detector 26 via the millimeter wave cable 25, and the wave detector 26 detects the input electromagnetic wave and outputs a voltage signal corresponding to the magnitude of the input electromagnetic wave. The output of the wave detector 26 is applied to an analog/digital converter 27, which converts the analog output of the wave detector 26 into a digital signal that can be processed by the microcomputer 28.

The microcomputer 28 is an analog/
A digital signal indicating the intensity of the reflected electromagnetic waves at each measurement point outputted from the digital converter 27 is input, and as in the conventional example explained in FIG. For example, each level range is assigned a plurality of gradations of a single color, and the intensity of reflected electromagnetic waves at each measurement point is colored. A determination is made as to whether or not this is the case, and the determination result is output to line 30. The details of this judgment will be explained in detail later.

The microcomputer 28 sends a signal in which the intensity of the reflected electromagnetic waves at each measurement point is colored to a monitor display 29, and the monitor display 29 displays the intensity of the reflected electromagnetic waves at each measurement point in a plurality of colors, for example, a single color. Display in gradation.

Next, the operation of this embodiment will be explained with reference to the flowchart of FIG.

First, the intensity of reflected electromagnetic waves at each measurement point is measured (step 201). This step 201 is shown in FIG.
This corresponds to steps 101 to 106 shown in FIG. however,
In this embodiment, a detector 26 and an analog/digital converter 27 are used in place of the spectrum analyzer 8 shown in FIG. 7, and an X
Since the antenna scanner 22 is a combination of two uniaxial scanners, an X-axis scanner movable in the axial direction and a Z-axis scanner movable in the Z-axis direction, the details of step 201 are as follows.

That is, first, the microcomputer 2
3 performs initial settings of the antenna scanner 22. That is, an initial setting command is given to the antenna scanner 22, the transmitting antenna 21a and the receiving antenna 21b are moved to the starting point, that is, the position of measurement point "1" shown in FIG. Digital information indicating the intensity of reflected electromagnetic waves at measurement point "1" is taken in from the output of the analog/digital converter 27.

Next, the microcomputer 28 supplies a predetermined number of pulses to the X-axis scanner of the antenna scanner 22, and transmits the transmitting antenna 21a and the receiving antenna 21.
b is moved in the X-axis direction, and the transmitting antenna 21a and the receiving antenna 21b are moved to the next measurement point "2".

Here, the microcomputer 28 determines the measurement point "2" from the output of the analog/digital converter 27.
captures digital information indicating the intensity of reflected electromagnetic waves at

In this way, the microcomputer 2
8 takes in digital information indicating the intensity of reflected electromagnetic waves from measurement point "1" to measurement point "30", supplies a predetermined number of pulses to the Y-axis scanner of the antenna scanner 22, and transmits the transmitting antenna 21a and the receiving antenna 21a. antenna 21
b is moved in the Z-axis direction, and the transmitting antenna 21a and the receiving antenna 21b are moved to the next measurement point "60".

Here, the microcomputer 28 selects the measurement point "60" from the output of the analog/digital converter 27.
” The digital information indicating the intensity of reflected electromagnetic waves is captured. Next, the microcomputer 28 supplies a predetermined number of pulses to the X-axis scanner of the antenna scanner 22, moves the transmitting antenna 21a and the receiving antenna 21b in the X-axis direction, and moves the transmitting antenna 21a and the receiving antenna 21b. Move to the next measuring point "59".

Here, the microcomputer 28 selects the measurement point "59" from the output of the analog/digital converter 27.
” The digital information indicating the intensity of reflected electromagnetic waves is captured. In this way, the microcomputer 28 takes in the digital information indicating the intensity of the reflected electromagnetic waves from the measurement point "60" to the measurement point "31", and supplies a predetermined number of pulses to the Y-axis scanner of the antenna scanner 22.
The transmitting antenna 21a and the receiving antenna 21b are
The transmitting antenna 21a and the receiving antenna 21b are moved in the axial direction to the next measuring point "61".

Similarly, microcomputer 2
8 takes in digital information indicating the intensity of reflected electromagnetic waves at all measurement points "1" to "900" from the output of the analog/digital converter 27.

When the acquisition of the digital information indicating the intensity of the reflected electromagnetic waves at all measurement points "1" to "900" is completed, the microcomputer 28 calculates the reflected intensity from the digital information indicating the intensity of the reflected electromagnetic waves at each measurement point. The maximum value of is found (step 202), and the position coordinates (x, y) of the transmitting antenna 21a and receiving antenna 21b that indicate this maximum value are searched for (step 203).

Next, the intensity distribution at each measurement point is examined by fixing the coordinate x and changing the coordinate y (step 204).
, it is determined whether this intensity distribution is monotonically decreasing (step 205). That is, each time the y-coordinate changes, the intensity of the previous reflected electromagnetic wave is compared with the current intensity, and if the current intensity is small, it is determined that the intensity distribution is decreasing monotonically. In this judgment, if it is judged that the intensity distribution is not monotonically decreasing (NO in step 205), the target object is assumed to have a curvature on its back surface (step 20
8), the microcomputer 28 outputs a signal to that effect, for example, a high level signal, to the line 30, and this flowchart ends.

On the other hand, if it is determined in step 205 that the intensity distribution is monotonically decreasing (YES in step 205), then the coordinate y is fixed and the coordinate x is changed to determine each measurement point. Examine the intensity distribution at (step 20
6), it is determined whether this intensity distribution is monotonically decreasing (step 207). In this judgment, if it is judged that the intensity distribution is not monotonically decreasing (step 20
7), the target object has a curvature on its back surface (step 208), and the microcomputer 28 outputs a signal to that effect, for example, a high-level signal, to the line 30, and ends this flowchart.

However, if it is determined in step 207 that the intensity distribution is monotonically decreasing (YES in step 207), then the target object is assumed to have no curvature on its back surface (step 209). ), the microcomputer 28 outputs a signal to that effect, for example, a low level signal, to the line 30, and this flowchart ends.

In the above embodiment, the position coordinates (x, y) of the transmitting antenna 21a and the receiving antenna 21b where the reflected intensity is the maximum value are searched, and the intensity is adjusted by changing the y or x coordinate at this point. We investigated whether the intensity distribution is decreasing monotonically, but this is just an example, and by changing both the x and y coordinates, we can check whether the intensity distribution is decreasing monotonically. It may be configured to check and identify whether or not the back surface of the target object has a curvature.

Although the flowchart of this embodiment does not show the formation of an image signal for the monitor display 29, the formation of an image signal for the monitor display 29 can be performed in the same manner as in the flowchart shown in FIG. can. That is, the minimum received strength and the maximum received strength are detected from the measured values at each measurement point, and the difference between the minimum received strength and the maximum received strength is, for example, 9.
The reception strength at each measurement point is divided into 1 to 9 categories, and the reception strength at each measurement point is divided into 1 to 9 categories.
Labeling is done with a numerical value of 9, and the points from the measurement point of the maximum reception strength (point belonging to the classification "1") to the measurement point of the minimum reception strength (point belonging to the classification "9") are labeled according to the reception strength. Coloring is performed using a single color with different gradations, and this is converted into an image on the monitor display 29. In this case, information regarding the shape of the target object can be obtained from the display on the monitor display 29. Note that color display may be used for the display on the monitor display 29.

Further, in the above embodiment, information indicating whether the back surface of the target object has a curvature is provided on the line 30.
Although the configuration is configured to output the information to the screen, it may be configured to directly display it on the monitor display 29.

[0051]

As explained above, according to the present invention, it is determined from the distribution of reflection intensity whether or not the back surface of the target object has a curvature. are the same, and even when it is difficult to identify the targets, it is possible to accurately identify the targets. The three-dimensional object label sorting device of the present invention can be applied, for example, to a visual sensor for a robot that sorts parts.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to claims of the present invention.

FIG. 2 is an explanatory diagram showing an embodiment of the present invention.

FIG. 3 is a diagram showing an example of measurement points in the embodiment shown in FIG. 2;

FIG. 4 is a flowchart explaining the operation of the embodiment shown in FIG. 2;

FIG. 5 is a diagram showing the distribution of reflected intensity of electromagnetic waves to explain the identification principle of the present invention.

FIG. 6 is a diagram illustrating a creeping wave phenomenon related to the identification principle of the present invention.

FIG. 7 is an explanatory diagram showing a conventional example of an object label classification device.

FIG. 8 is a diagram showing an example of measurement points in the conventional example shown in FIG. 7;

FIG. 9 is a flowchart illustrating the operation of the conventional example shown in FIG. 7;

[Explanation of symbols]

a Electromagnetic wave transmitting/receiving means b Reflection intensity distribution measuring means c Back shape determining means 1, 21 Antenna 1a, 21a Transmitting antenna 1b, 21b Receiving antenna 2 Antenna moving table 3, 23 Gun oscillator 4, 24, 7, 25 Millimeter wave Cable 5, 5' Target 6 Unit 8 Spectrum analyzer 10, 28 Microcomputer 11, 29 Monitor display 26 Detector 27 A/D converter

Claims (1)

[Claims] 1. An electromagnetic wave transmitting/receiving means that irradiates electromagnetic waves forward at multiple points and measures the reflected intensity thereof, and a reflected intensity that measures the distribution of the reflected intensity from the center to the edge of a target object. a distribution measuring means; a back surface shape determining means for determining that the back surface of the target object does not have curvature if the distribution of reflection intensity measured by the measuring means monotonically decreases from the center to the edge of the target object; A three-dimensional object labeling device characterized by comprising: