JPH10318716A - Method and apparatus for position detection of object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for the position detection of an object, which are simple and whose detecting time is short. SOLUTION: Cross-shaped slit light 4 which is crossed at angles other than a right angle is irradiated vertically. The image of a rectangular parallelepiped 1 irradiated with the cross-shaped slit light 4 is fetched into an image processing means by using an imaging means 7. Positions of four points of intersection in which the cross-shaped slit light 4 is crossed with the outline of the rectangular parallelepiped 1 are found. By one measuring operation, the movement amount and the rotation amount of the rectangular parallelepiped 1 can be decided unconditionally.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting the position and direction on a plane of an object having a rectangular outline when viewed from above.

[0002]

2. Description of the Related Art A method for detecting the position and direction of a rectangular object on a plane according to the prior art will be described with reference to the drawings. FIG. 4 is a perspective view showing an example of the prior art. In the figure, reference numeral 1 denotes a rectangular parallelepiped to be detected, which is placed on a plane (not shown).
The reference position and direction of the rectangular parallelepiped 1 to be placed on the plane are determined. However, since the parallel movement and the rotation around the vertical axis are free on the plane, the actual position and direction are unknown. This is a problem encountered, for example, when picking roughly positioned articles with an industrial robot. Reference numeral 2 denotes a rectangle, which is an outline when the rectangular parallelepiped 1 is viewed from above. Reference numeral 5 denotes a light source, which is fixed above the rectangular parallelepiped 1 and cross-shaped slit light 6 intersecting at a right angle.
Irradiate on top. Reference numeral 7 denotes imaging means such as a video camera, which is fixed above the rectangular parallelepiped 1 and has slit light 6.
The image of the rectangle 2 illuminated by the image is taken and sent to an image processing device (not shown). FIG. 5 is an explanatory diagram showing an image of the rectangle 2 captured by the imaging unit 7. In the figure, R1, R
2, R3 and R4 are intersections where the side of the rectangle 2 and the cross-shaped slit light 6 intersect. The intersections R1, R2, R3, R4
In the image processing means, for example, a point at which the intensity of the reflected light of the cross-shaped slit light 6 becomes discontinuous due to a difference in reflectance between the plane of the background and the rectangle 2 is obtained.
The position and direction of the rectangle 2 are calculated from the positions of the intersections R1, R2, R3, and R4, and the position and direction of the rectangular parallelepiped 1 are calculated by a calculation device (not shown).

[0003]

However, in the prior art, there is a problem that the position and direction of the rectangle 2 cannot be uniquely specified simply by obtaining the positions of the intersections R1, R2, R3, and R4. FIG. 6 is an explanatory diagram showing a method of determining the position of the rectangle 2 by knowing the positions of the intersections R1, R2, R3, and R4. In the figure, A is a rectangle 2 actually photographed.
B has four points R1, R2, R
3, another rectangle passing through R4. As shown in FIG.
There are two solutions for the position and direction of the rectangle passing through R2, R3, and R4. Therefore, in order to determine the position and the direction of the rectangle 2, it is necessary to determine whether the rectangle 2 is at the position A or B by another auxiliary means. There is also a problem that the detection becomes complicated and takes a long time. Therefore, an object of the present invention is to provide an object position detecting method and an object position detecting device which are simple and have a short detection time.

[0004]

In order to solve the above-mentioned problems, the present invention irradiates an object to be detected with a cross-shaped slit light that intersects at an angle other than a right angle, and detects the slit light and the contour of the object. Are obtained to obtain the position and direction of the object. Further, two distance measuring means arranged above the object and measuring a distance in a direction perpendicular to the plane scans a straight line intersecting at an angle other than a right angle on a plane parallel to the plane, The position and the direction of the object are obtained by obtaining four intersections where the scanning trajectory intersects the contour of the object.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a first embodiment of the present invention. Since the basic configuration is the same as that of the related art, different portions will be described. In the figure, reference numeral 3 denotes a light source, which is fixed above the rectangular parallelepiped 1 and irradiates the cross-shaped slit light 4 on the rectangular parallelepiped 1 at an angle other than a right angle. The imaging means 7 captures the rectangle 2 illuminated by the cross-shaped slit light 4 and sends the image to an image processing device (not shown). FIG. 2 is a plan view showing an image of the rectangle 2 taken by the image pickup means 7. In the figure, P1, P2, P3,
P4 is the intersection of the slit light 4 and the rectangle 2, and Q
1, Q2, Q3, and Q4 are vertices of the rectangle 2. Since the reflection intensity of the cross-shaped slit light 4 is different between the rectangle 2 and the other portions, a point where the reflection intensity of the slit light 4 becomes discontinuous is obtained. , P2, P3, and P4. Next, these four intersections P
A method for obtaining the position and direction of the rectangle 2 from 1, P2, P3, and P4 will be described. Now, when the rectangle 2 is placed at the reference position and direction, the four vertices are represented by q1, q2, q
3, q4, and the respective coordinates are determined as follows.

(Equation 1) Here, a and b are known numerical values, and 2a and 2b are the lengths of two sides of the rectangle 4. Next, this rectangle 2 has an angle θ
, And the vertices of the rectangle 2 when translated by (α, β) are Q1, Q2, Q3, and Q4. The coordinates of the vertices before and after movement are (x, y),
(X, Y)

(Equation 2) There is a relationship. Here, c = cos θ and s = sin θ. Determining the position and direction of the rectangle 2 means determining the translation amounts α and β and the rotation angle θ. Now, of the cross-shaped images that the cross-shaped slit light 4 creates on the rectangle 2,
Take one straight line image on the y-axis, and let other intersecting straight line images be y = k
The straight line of x is set, and the intersection of the two straight line images is set as the origin. Here, k is a known constant determined by the angle between the two straight lines. Point P1 is the intersection of side Q1Q2 and straight line y = kx, point P2 is the intersection of side Q2Q3 and the y-axis, and point P3 is side Q3.
The intersection of Q4 and the straight line y = kx, point P4, is the intersection of the side Q4Q1 and the y-axis. From equations 1 and 2, points Q1, Q2, Q3, Q
4 can be obtained. Assuming that the x-coordinates of the points P1 and P3 are X1 and X2, and the y-coordinates of the points P2 and P4 are Y2 and Y4, the following relationship exists.

(Equation 3)

(Equation 4)

(Equation 5)

(Equation 6) The following equations are obtained from Equations 3 and 4.

(Equation 7) The following equations are obtained from Equations 5 and 6.

(Equation 8) The following equations are obtained from Equations 3 and 5.

(Equation 9)

(Equation 10) Further, by substituting Equations 7 and 8 into Equations 9 and 10, α and β can be obtained. Further, when the cross-shaped slit light 4 is orthogonal as shown in the related art, the straight line of one slit coincides with the x-axis. That is, k = 0. At this time, Equation 8 does not hold, and s is not uniquely determined, so that a solution cannot be determined. FIG.
FIG. 4 is a plan view showing a second embodiment of the present invention. In the figure, reference numeral 8 denotes a part located above the rectangular parallelepiped 1 and scanning in one direction.
Each scanning direction 9 intersects at an angle other than a right angle, and the measuring direction of the distance is a direction perpendicular to the rectangle 2 to be detected. The distance to the rectangle 2 is obtained by scanning the distance measuring means 8, and a point at which the change in distance is discontinuous is detected as an intersection of the scanning direction and the rectangular parallelepiped 1,
Find its position. The position of the intersection is input to a calculation device (not shown), and the position and direction of the rectangle 2 are obtained in the same procedure as in the first embodiment. The object to be detected according to the present invention may be any object having a rectangular outline shape when viewed from above. For example, the present invention can be applied to a rectangular hole or a concave portion opened in a plane.

[0006]

As described above, according to the present invention, the following effects can be obtained. (1) Since the cross-shaped slit lights intersect at an angle other than a right angle, the position and direction of an object having a rectangular plane can be detected with a simple device. (2) The operation formula is simple, and the operation processing time is short.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a plan view of an image showing the first embodiment of the present invention.

FIG. 3 is a plan view showing a second embodiment of the present invention.

FIG. 4 is a perspective view showing an example of the prior art.

FIG. 5 is a plan view showing an example of the related art.

FIG. 6 is a plan view showing an example of the related art.

[Explanation of symbols]

 1: rectangular parallelepiped 2: rectangular 3: light source 4: cruciform slit light 5: light source 6: cruciform slit light 7: imaging means 8: distance measuring means 9: scanning direction

Claims (4)

[Claims] 1. An object position detecting method for detecting a position and a direction on a plane of an object having a rectangular outline when viewed from above, wherein a cross-shaped slit light intersecting at an angle other than a right angle is applied to the plane. Irradiated vertically to the object, the image of the object illuminated by the cross-shaped slit light is taken into image processing means using an imaging means, and the positions of four intersections where the cross-shaped slit light intersects the contour of the object are determined. An object position detecting method for obtaining the position and direction of the object from the positions of the four intersections. 2. An object position detecting method for detecting a position and a direction on a plane of an object having a rectangular outline when viewed from above, wherein the distance is set above the object and perpendicular to the plane. Two distance measuring means for measuring
In a plane parallel to the plane, scan so as to intersect at an angle other than a right angle, determine the positions of four intersections where the trajectory of the scan intersects the contour of the object, and determine the position of the object from the positions of the four intersections. An object position detection method that determines the position and direction. 3. An object position detecting device for detecting a position and a direction on a plane of an object having a rectangular outline when viewed from above, wherein the object is disposed above the object and intersects at an angle other than a right angle. A light source for irradiating a vertical slit light with respect to the plane, and disposed above the object;
An object position detection device, comprising: an imaging unit that captures an image of the object illuminated by the cross-shaped slit light; an image processing device; and a calculation device. 4. An object position detecting device for detecting the position and direction of an object having a rectangular outline when viewed from above on a plane, wherein the distance is set above the object and perpendicular to the plane. An object position detecting device, comprising: two distance measuring means for scanning a straight line intersecting at an angle other than a right angle in a plane parallel to the plane, and a calculating device.