Automatic calibration method

• US 5,471,312 A
• Filed: 02/19/1993
• Issued: 11/28/1995
• Est. Priority Date: 07/04/1991
• Status: Expired due to Term

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Warashina, Fumikazu, Terawaki, Fumikazu, Watanabe, Atsushi
• Primary Examiner(s): Reinhart, Mark J.
• Application Number:
  US07/975,557
• Time in Patent Office: 1,012 Days
• Field of Search: 346/1.1, 346/108, 346/160, 382/22, 382/23, 382/21, 382/15, 382/16, 358/296, 347/256
• US Class Current: 358/296
• CPC Class Codes: B25J 9/1692 Calibration of manipulator
• CPC Class Codes: G05B 19/4015 going to a reference at the beginning of machine cycle, e.g. for calibration

Abstract

A method for automatically effecting calibration between an image processing apparatus and a control device of an automatic machine. Jig data for calibration and the position of a robot, fitted with a jig which can be photographed by a camera at the time of calibration, are previously given as instructions. In response to a calibration command, the robot, fitted with the jig, moves to a point of instruction, the image processing apparatus photographs the jig and fetches an image after the movement. A calibration process is executed in accordance with data of the photographed image, set jig data, and robot position. When the jig data and the instruction point are first set and given once as instructions, the calibration thereafter can be automatically effected only by mounting the jig on the robot and inputting the calibration command.

Claims

1. A method of automatically calibrating a camera of an image processing apparatus which processes an image of an object of operation by combining a work coordinate system set in a control device of an automatic machine with a camera coordinate system set in the image processing apparatus, said method comprising the steps of:

(a) giving the automatic machine an instruction point for a position of the automatic machine wherein a whole body of a jig mounted on the automatic machine comes within the range of the camera of the image processing apparatus, and storing first data of the instruction point in first storage means in the automatic machine;

(b) setting, in the image processing apparatus, second data relating to an object of recognition attached to said jig, and storing said second data relating to the object of recognition in second storage means in the image processing apparatus;

(c) mounting said jig on the automatic machine;

(d) issuing a calibration start command to actuate the image processing apparatus and the automatic machine;

(e) moving the automatic machine to said instruction point based on said first data stored in said first storage means;

(f) photographing said jig with the camera, to produce image data; and

(g) combining the camera coordinate system and the work coordinate system in accordance with the image data obtained by said photographing in said step (f), said second data relating to the object of recognition stored in said second storage means, and said position data of the automatic machine at said instruction point, while maintaining communication between the image processing apparatus and the automatic machine;

said steps (e), (f) and (g) being automatically repeated in response to said calibration start command issued in said step (d).

2. The automatic calibration method according to claim 1, wherein said step (b) further comprises the step of storing data of a position and attitude of said jig mounted on the automatic machine in the image processing apparatus.

5. The automatic calibration method as claimed in claim 2, wherein said step (g) further comprises the steps of:

combining the camera coordinate system and the work coordinate system based upon the mounting position and attitude data of said jig.

8. The automatic calibration method as claimed in claim 1, wherein the object of recognition comprises a pattern which includes a first circle of a first size and a second circle of a second size different than said first size.

9. The automatic calibration method as claimed in claim 1, wherein the object of recognition comprises a pattern which includes a first circle of a first size and a plurality of second circles of a second size different than said first size and arranged in a lattice formation.

3. A method of automatically calibrating a camera of an image processing apparatus for processing an image of an object of operation by combining a work coordinate system set in a control device of an automatic machine with a camera coordinate system set in the image processing apparatus, said method comprising the steps of:

(a) giving the automatic machine an instruction point for a position of the automatic machine wherein a whole body of a jig mounted on the automatic machine comes within the range of the camera of the image processing apparatus, and storing first data of the instruction point in first storage means in the automatic machine;

(b) setting, in the image processing apparatus, second data relating to an object of recognition attached to said jig based upon one of a plurality of types of calibration, and storing said second data relating to the object of recognition in second storage means in the image processing apparatus;

(c) mounting said jig based upon the one of the plurality of calibration types to be used on the automatic machine and inputting the one of the plurality of calibration types;

(d) issuing a calibration start command to actuate the image processing apparatus and the automatic machine;

(e) moving the automatic machine to said instruction point based upon said first data stored in said first storage means;

(f) photographing said jig with the camera to produce image data; and

(g) combining the camera coordinate system and the work coordinate system in accordance with the image data obtained by said photographing in said step (f), said second data relating to the object of recognition stored in said second storage means, and said position data of the automatic machine at the instruction point, while maintaining communication between the image processing apparatus and the automatic machine,

said steps (e), (f) and (g) being automatically repeated in response to said calibration start command issued in said step (d).

4. The automatic calibration method according to claim 3, wherein said step (b) further comprises the step of storing data of a position and attitude of said jig mounted on the automatic machine in the image processing apparatus.

6. The automatic calibration method as claimed in claim 4, wherein said step (g) further comprises the steps of:

combining the camera coordinate system and the work coordinate system based upon the mounting position and attitude data of said jig.

7. The automatic calibration method as claimed in claim 3, wherein said plurality of calibration types comprise two-dimensional calibration and three-dimensional calibration.