JPH06294618A - Method and system for detecting relative position and angle between two object and marker therefor - Google Patents

Abstract

PURPOSE:To provide method and system for detecting the relative position and angle between two objects at an arbitrary position and a marker used therein. CONSTITUTION:The marker comprises main and auxiliary markers 10, 16 spaced apart by a central distance L wherein the main marker 10 comprises a plurality of chevrons 12 having inclining faces of different colors whereas the auxiliary marker 16 comprises a plurality of concentric circles of different colors. A visual sensor recognizes the marker and detects the relative angles between two objects in two directions based on the ratio of areas of different colors. The distance between two objects is then operated based on the relative angles, the angle theta between the line connecting the centers O, O' and the line connecting the two objects, and the distance between the centers O, O' on an image, thus detecting the relative position of two objects.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for detecting a relative position and an angle between two objects and a marker used for the method and apparatus.

[0002]

2. Description of the Related Art In outer space, it is necessary for installation and assembly of equipment to detect a relative position between two objects, for example, a relative position and a relative angle between a robot arm and a target by a visual sensor. Further, even in a general assembly plant or the like, it is often necessary to detect the relative position and the relative angle between two objects remotely and in a non-contact manner, such as an arm of a welding robot and a non-welded object.

[0003]

In order to meet such a need, conventionally, for example, one of two objects is fixed at a predetermined position and the relative position of the other object, for example, a robot arm, is determined from the movement distance of the arm. Numerical calculation was performed, and the relative position and relative angle between the two objects were calculated from this. However, such means has a problem that a large error occurs when the actual object position deviates from the calculated position. Further, there is a problem that such means is difficult to apply when the relative distance between two objects is large. Therefore, conventionally, for example, by attaching an appropriate detection marker to one of two objects,
There has been a demand for means for providing a visual sensor on the other side of the object and recognizing the marker by the visual sensor to detect the relative position and relative angle between the two objects. As means for satisfying a part of the demand, for example, a marker having a predetermined length is attached to one side, the marker is recognized by a visual sensor from directly above the marker, and the distance between the image-shaped markers is determined by the visual sensor and Corrected by the scale factor on the image display,
A means for detecting the distance between the marker and the visual sensor, that is, the relative position between the two objects has been proposed and has been partially implemented. However, such a method has a problem that it is necessary to position the visual sensor directly above the marker.

The present invention was created to completely satisfy the above-mentioned needs. That is, the object of the present invention is to
It can be detected from the actual object position without fixing the object, and can be applied even when the relative distance between the two objects is large, and further, without fixing the relative position between the two objects to a specific position, It is an object of the present invention to provide a method and apparatus capable of detecting a relative position and an angle between two objects from a free position and a marker used for the method and apparatus.

[0005]

According to the present invention, a marker is attached to one of two objects, and a visual sensor is provided on the other of the two objects. The visual sensor recognizes the marker to detect the relative position between the two objects. And a method for detecting an angle, wherein the marker comprises a main marker and an auxiliary marker whose centers are separated by a predetermined distance L, and the main marker has a plurality of concentric chevron portions, and one of the chevron portions is formed. The inclined surface and the other inclined surface have different lightness, saturation, or hue, the marker is recognized by the visual sensor, and the two orthogonal directions a passing through the center O of the recognized main marker,
For b, the area ratio between one inclined surface and the other inclined surface is calculated from the difference in brightness, saturation, or hue to detect the relative angles α and β between the two objects in two directions, and the detected 2
Angle θ formed by the line connecting two objects, the relative angle α, β, and the line connecting the center O of the main marker and the center O ′ of the auxiliary marker on the image, the center O of the main marker on the image, and the auxiliary marker The distance between the two objects is calculated from the distance L ′ from the center O ′ of
There is provided a method for detecting the relative position and angle between two objects, characterized in that the relative position x, y, z between the two objects is detected.

Further, according to the present invention, a marker attached to one of the two objects and a visual sensor attached to the other of the two objects are provided, and the visual sensor recognizes the marker to detect the relative distance between the two objects. A device for detecting a position and an angle, wherein the marker is composed of a main marker and an auxiliary marker whose centers are separated by a predetermined distance L, and the main marker has a plurality of concentric chevron portions, The one inclined surface and the other inclined surface have different lightness, saturation or hue, and further, the marker is recognized by the visual sensor, and two orthogonal directions a passing through the center O of the recognized main marker. , B, the area ratio between one inclined surface and the other inclined surface is calculated from the difference in lightness, saturation or hue to detect the relative angles α and β between the two objects in two directions, and the detected 2 Horn The relative angles α, β, the angle θ formed by the line connecting the center O of the main marker and the center O ′ of the auxiliary marker on the image with the line connecting the two objects, and the center O of the main marker on the image
And the distance L ′ between the center O ′ of the auxiliary marker and the distance between the two objects, and the relative position x,
There is provided a device for detecting a relative position and an angle between two objects, which is provided with an arithmetic device for detecting y and z.
The arithmetic unit binarizes visual data of different lightness, saturation, or hue recognized by the visual sensor using a constant threshold value, and one of the inclined surface and the other inclined surface of the marker recognized by this binarization. It is preferable to calculate the area ratio and detect the relative angle between the two objects.

Further, according to the present invention, a marker attached to one of the two objects and a visual sensor attached to the other of the two objects are provided, and the visual data of the marker recognized by the visual sensor A marker used to detect a relative position and an angle between objects, wherein the marker is composed of a main marker and an auxiliary marker whose centers are separated by a predetermined distance L, and the main marker has a plurality of concentric chevron shapes. There is provided a marker having a portion, wherein one inclined surface of the chevron portion and the other inclined surface have different lightness, saturation or hue.

[0008]

According to the present invention, the main marker has a plurality of concentric circular chevron portions, and one slanted surface and the other slanted surface of the chevron portion have different lightness, saturation, or hue. , Orthogonal 2 passing through the center O of the recognized main marker
For the directions a and b, the area ratio between the one inclined surface and the other inclined surface is calculated from the difference in lightness, saturation, or hue to obtain 2
It is possible to detect the relative angles α and β between the two objects in the direction. Such detection is performed by binarizing the visual data of different lightness, saturation or hue recognized by the visual sensor using a certain threshold value, and the area between one inclined surface and the other inclined surface of the marker recognized by this binarization. It can be easily implemented by calculating the ratio and detecting the relative angle between the two objects. Then the two detected relative angles α,
β, the angle θ formed by the line connecting the center O of the main marker on the image and the center O ′ of the auxiliary marker with the line connecting the two objects, and the center O of the main marker on the image and the center O ′ of the auxiliary marker. The distance L ′ between the two objects is calculated from the distance L ′ and the relative position x, y, z between the two objects is detected from these to obtain 2
The relative position and angle between two objects can be detected from a free position without fixing the relative position between the objects to a specific position. The present invention can be implemented without fixing the object, only by attaching the marker to one of the two objects and providing the visual sensor on the other of the two objects. Furthermore, only the marker is recognized by the visual sensor.
It can be easily applied even when the relative distance between objects is large. Further, since the marker is attached to the actual object, the relative angle can be detected without causing an error even if the actual object position deviates from the calculated position.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a device for detecting a relative position and an angle between two objects according to the present invention. In this figure, the device for detecting relative angles according to the invention comprises a main marker 10 attached to one of the two objects 1 and a visual sensor 20 attached to the other 2 of the two objects. The main marker 10 and the visual sensor 20 are preferably mounted parallel to the respective reference lines (for example, axes) of the two objects 1 and 2. Thereby, the relative angle A between the two objects can be matched with the relative angle between the main marker 10 and the visual sensor 20. Hereinafter, this case will be described. The main marker 10 or the visual sensor 20 may be attached while being inclined with respect to the reference line.

The main marker 10 has a plurality of concentric chevron portions 12.
And the other inclined surface 13 and the other inclined surface 14 of the chevron portion 12 have different lightness, saturation or hue. The means for dividing the inclined surfaces 13, 14 into different lightness, saturation or hue is a well-known means such as painting or plating.
The difference in lightness, saturation, or hue may be any difference as long as it can be distinguished by the visual sensor. For example, if they are painted white and black, it is possible to easily distinguish them by the difference in brightness. Further, for example, white and red, black and red, and the like can be easily distinguished by either lightness, saturation, or hue. Visual sensor 2
Reference numeral 0 is, for example, a television camera provided with a CCD having a high resolution, and it is preferable to have an appropriate filter according to the brightness, saturation or hue of the inclined surface of the marker.

The detection apparatus according to the present invention further calculates the area ratio between the one inclined surface 13 of the main marker 10 and the other inclined surface 14 recognized by the visual sensor 20 from the difference in lightness, saturation or hue. The arithmetic unit 30 is provided. The arithmetic unit 30 is, for example, a computer, which binarizes a certain range of the main marker 10 recognized by the visual sensor 20 using visual data of different lightness, saturation, or hue using a certain threshold value, and recognizes the binarized data. Main marker 1
The area ratio between the one inclined surface 13 and the other inclined surface 14 is calculated to detect the relative angle between the two objects. Incidentally, 32 is a CRT, which displays an image by the visual sensor 20.

The relative angle between two objects is first detected by the visual sensor 20 by the relative angle detecting device, and the recognized main marker 10 is detected.
It is detected by calculating the area ratio between the one inclined surface 13 and the other inclined surface 14 from the difference in lightness, saturation or hue. The detected relative angle A is a relative angle between two objects in a plane perpendicular to the plurality of linear chevron portions 12 of the main marker 10 (in the plane in FIG. 1). The visual sensor 20 does not necessarily have to be positioned in a plane perpendicular to the chevron portion 12 of the main marker 10. For example, even if the chevron sensor 12 faces the chevron portion 12 of the main marker 10 at an angle, the same can be achieved by the above-described detection device. Relative angle A can be detected.

FIG. 2 is a plan view (A) and a side sectional view (B) of the marker according to the present invention. In this figure, the marker comprises a main marker 10 and an auxiliary marker 16 whose centers are separated by a predetermined distance L. Main marker 10
Has a plurality of concentric chevron portions 12 as shown in FIG. 1, one slanted surface 13 of this chevron portion and the other slanted surface 1
4 has different lightness, saturation or hue. Also,
The auxiliary marker 16 has a flat plate shape as a whole, and has a plurality of concentric circles, and the concentric circles have mutually different brightness, saturation, or hue. The central portion of the main marker 10 has a planar shape, which facilitates recognition from any angle. In addition, such a configuration of the auxiliary marker 16 is not essential, and may be a shape that can recognize at least the center, for example, a simple point or a circle.

The arithmetic unit 30 according to the present invention further recognizes the markers 10 and 16 by the visual sensor 20 and one inclined surface in two orthogonal directions a and b passing through the center O of the recognized main marker 10. 13 and the other inclined surface 14 are calculated from the difference in lightness, saturation or hue to detect the relative angles α and β between the two objects in two directions, and the two detected relative angles α and β. And a line connecting the center O of the main marker and the center O ′ of the auxiliary marker on the image is 2
The angle θ formed by the line connecting the objects and the distance L ′ between the center O of the main marker and the center O ′ of the auxiliary marker on the image are calculated from the distance between the two objects, and the relative distance between the two objects is calculated from these. The position x, y, z is detected.

The device according to the invention described above is used as follows. First, the markers 10 and 16 are recognized by the visual sensor 20 shown in FIG. 1, and the markers 10 and 16 are displayed as an image. The markers 10 and 16 on the image are, for example, as shown in FIG.
Is displayed as if viewed from an angle. Next, two orthogonal directions a and b passing through the center O of the recognized main marker 10.
For the line segment (horizontal and vertical axes on the image are preferable),
The area ratio between the one inclined surface 13 and the other inclined surface 14 is calculated from the difference in lightness, saturation or hue to detect the relative angles α, β between the two objects in the two directions. This detection method is the above-described method of detecting the angle A in FIG. That is, the visual data on the straight line of the radius from the center O of the main marker 10 recognized by the visual sensor 20 to the a direction is binarized using a certain threshold value, and one inclination of the main marker 10 recognized from this is binarized. The area ratio between the surface 13 and the other inclined surface 14 is calculated to detect the relative angle α between the two objects. Similarly, the relative angle β can be detected from the visual data on the straight line of the radius from the center O in the b direction. The relative angles α and β may be obtained from the visual data for the diameter instead of the visual data for the radius. Then, the detected two relative angles α and β and the center O of the main marker on the image
And the center O'of the auxiliary marker form an angle θ with the line connecting the two objects, and the distance L'between the center O of the main marker and the center O'of the auxiliary marker on the image The distance is calculated, and the relative position x, y, z between the two objects is detected from these. That is, the distance (actual distance) L between the centers of the markers
Are displayed at a distance L'on the image, and the main marker 1
The angle between 0 and the image plane of the visual sensor 20 can be calculated from the three relative angles α, β, and θ, and the scale factor of the marker on the image by the visual sensor and the image display is known. The distance between the main marker 10 and the visual sensor 20 can be calculated from this, and the relative position x, y, z between the two objects can be detected from these.

[0016]

As described above, according to the present invention, the main marker has a plurality of concentric circular chevron portions, and one slanted surface of this chevron portion and the other slanted surface have different lightness, saturation or hue. Therefore, in two orthogonal directions a and b passing through the center O of the recognized main marker, the area ratio between one inclined surface and the other inclined surface is calculated from the difference in lightness, saturation or hue. Then, the relative angles α and β between the two objects in the two directions can be detected. Such detection is performed by binarizing the visual data of different lightness, saturation or hue recognized by the visual sensor using a certain threshold value, and the area between one inclined surface and the other inclined surface of the marker recognized by this binarization. It can be easily implemented by calculating the ratio and detecting the relative angle between the two objects. Then, the detected two relative angles α and β and the center O of the main marker on the image
And the center O'of the auxiliary marker form an angle θ with the line connecting the two objects, and the distance L'between the center O of the main marker and the center O'of the auxiliary marker on the image By calculating the distance and detecting the relative position x, y, z between the two objects from these, the relative position between the two objects can be changed from a free position without fixing the relative position between the two objects to a specific position. The target position and angle can be detected. The present invention can be implemented without fixing the object, only by attaching the marker to one of the two objects and providing the visual sensor on the other of the two objects. Furthermore, only the marker is recognized by the visual sensor, and it can be easily applied even when the relative distance between two objects is large. Further, since the marker is attached to the actual object, the relative angle can be detected without causing an error even if the actual object position deviates from the calculated position.

Therefore, the method and apparatus for detecting the relative position and angle between two objects of the present invention, and the marker used therefor are as follows:
It can be detected from the actual object position without fixing the object, and can be applied even when the relative distance between the two objects is large, and further, without fixing the relative position between the two objects to a specific position, It has an excellent effect that the relative position and angle between two objects can be detected from a free position.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a device for detecting a relative position and an angle between two objects according to the present invention.

FIG. 2 is a plan view and a side sectional view of a marker according to the present invention.

[Explanation of symbols]

 1 and 2 object 10 main marker 12 chevron portion 13 and 14 inclined surface 16 auxiliary marker 20 visual sensor 30 arithmetic unit 32 CRT

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideyuki Ando 3-1-15-1 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries Co., Ltd. Toni Technical Center (72) Inventor Shuntaro Suzuki 3-chome, Toyosu, Koto-ku, Tokyo No. 1-15 Ishikawajima Harima Heavy Industries Co., Ltd. Toji Technical Center

Claims (4)

[Claims] 1. A marker attached to one of two objects,
A method for detecting a relative position and an angle between two objects by providing a visual sensor on the other side of the object and recognizing the marker by the visual sensor, wherein the marker is a main body whose center is separated by a predetermined distance L. The marker comprises a marker and an auxiliary marker, the main marker has a plurality of concentric chevron portions, one inclined surface of the chevron portion and the other inclined surface have different lightness, saturation or hue, the visual sensor The marker is recognized by the following, and the area ratio between one inclined surface and the other inclined surface is calculated from the difference in lightness, saturation, or hue in two orthogonal directions a and b passing through the center O of the recognized main marker. Then, the relative angles α and β between the two objects in two directions are detected, and a line connecting the detected two relative angles α and β and the center O of the main marker and the center O ′ of the auxiliary marker on the image is drawn. A line connecting two objects Angle θ and a center O of the main marker on the image and 'distance L between the' center O of the auxiliary marker, calculates the distance between two objects from the relative position x between these two objects, y,
A method of detecting a relative position and an angle between two objects, characterized by detecting z. 2. A marker attached to one of the two objects, and a visual sensor attached to the other of the two objects, and the marker is recognized by the visual sensor to detect the relative position and angle between the two objects. In the device, the marker comprises a main marker and an auxiliary marker whose centers are separated by a predetermined distance L, and the main marker has a plurality of concentric chevron portions, and one inclined surface of the chevron portion and the other. The inclined surface has different lightness, saturation or hue, and further, the marker is recognized by the visual sensor,
Regarding two directions a and b orthogonal to each other that pass through the center O of the recognized main marker, the area ratio between one inclined surface and the other inclined surface is calculated from the difference in lightness, saturation, or hue to obtain two objects in two directions. The relative angles α and β between the two are detected, and the detected two relative angles α and β and the center O of the main marker on the image
And the center O'of the auxiliary marker form an angle θ with the line connecting the two objects, and the distance L'between the center O of the main marker and the center O'of the auxiliary marker on the image A device for detecting a relative position and an angle between two objects, comprising a calculation device for calculating a distance and detecting a relative position x, y, z between the two objects from these. 3. The computing device binarizes visual data of different lightness, saturation, or hue recognized by a visual sensor using a certain threshold value, and one sloped surface of the marker and the other recognized by the binarized data. 3. The relative position and angle detection device between two objects according to claim 2, wherein an area ratio with respect to the inclined surface is calculated to detect a relative angle between the two objects. 4. A relative position between two objects, comprising a marker attached to one of the two objects and a visual sensor attached to the other of the two objects, and from the visual data of the marker recognized by the visual sensor. And a marker used for detecting an angle, wherein the marker is composed of a main marker and an auxiliary marker whose centers are separated by a predetermined distance L, and the main marker has a plurality of concentric chevron portions, A marker characterized in that one sloped surface of the chevron portion and the other sloped surface have different lightness, saturation or hue.