Method and system for performing automatic camera calibration for robot control

A method for performing robot control, the method comprising:

• generating, by a robot control system, a movement command for outputting to a communication interface of the robot control system, wherein the communication interface is configured to communicate with a robot having a base and a robot arm with a calibration pattern disposed thereon, and is configured to communicate with a camera having a camera field of view;
• outputting, by the robot control system, the movement command to the communication interface, wherein the communication interface is configured to communicate the movement command to the robot to cause the robot arm to move the calibration pattern to at least one location in the camera field of view;
• receiving, by the robot control system, a calibration image, wherein the communication interface is configured to receive the calibration image from the camera, the calibration image being an image of the calibration pattern at the at least one location in the camera field of view, and wherein the calibration pattern includes a plurality of pattern elements having respective defined pattern element locations in a pattern coordinate system, wherein the pattern coordinate system is a coordinate system defined with respect to a location and orientation of the calibration pattern;
• determining, by the robot control system, a plurality of image pattern element locations from the calibration image, wherein the plurality of image pattern element locations indicate respective locations at which the plurality of pattern elements appear in the calibration image;
• determining, by the robot control system, an estimate of a first intrinsic camera parameter of a first type based on the plurality of image pattern element locations and based on the defined pattern element locations and without having previously determined an estimate of an intrinsic camera parameter of a second type;
• determining, by the robot control system, an estimate of a second intrinsic camera parameter of the second type based on the estimate of the first intrinsic camera parameter of the first type and based on an amount of curvature detected between the plurality of image pattern element locations;
• and
• determining, by the robot control system, based on the estimate of the first intrinsic camera parameter of the first type and the estimate of the second intrinsic camera parameter of the second type, an estimate of a transformation function that describes a relationship between a camera coordinate system and a world coordinate system, wherein the camera coordinate system is a coordinate system defined with respect to a location and orientation of the camera that the communication interface is configured to communicate with, and the world coordinate system is a coordinate system defined with respect to a location that is stationary relative to the base of the robot that the communication interface is configured to communicate with.

A non-transitory computer-readable medium having instructions stored thereon that, when executed by a control circuit of a robot control system, causes the control circuit to perform camera calibration by:

• generating a movement command for outputting to a communication interface of the robot control system, wherein the communication interface is configured to communicate with a robot having a base and a robot arm with a calibration pattern disposed thereon, and with a camera having a camera field of view;
• outputting the movement command to the communication interface, wherein the communication interface is configured to communicate the movement command to the robot to cause the robot arm to move the calibration pattern to at least one location in the camera field of view;
• receiving a calibration image, wherein the communication interface is configured to receive the calibration image from the camera, the calibration image being an image of the calibration pattern at the at least one location in the camera field of view, and wherein the calibration pattern includes a plurality of pattern elements having respective defined pattern element locations in a pattern coordinate system, wherein the pattern coordinate system is a coordinate system defined with respect to a location and orientation of the calibration pattern;
• determining a plurality of image pattern element locations from the calibration image, wherein the plurality of image pattern element locations indicate respective locations at which the plurality of pattern elements appear in the calibration image;
• determining an estimate of a first intrinsic camera parameter of a first type based on the plurality of image pattern element locations and based on the defined pattern element locations and without having previously determined an estimate of an intrinsic camera parameter of a second type;
• determining an estimate of a second intrinsic camera parameter of the second type based on the estimate of the first intrinsic camera parameter of the first type and based on an amount of curvature detected between the plurality of image pattern element locations;
• and
• determining, based on the estimate of the first intrinsic camera parameter of the first type and the estimate of the second intrinsic camera parameter of the second type, an estimate of a transformation function that describes a relationship between a camera coordinate system and a world coordinate system, wherein the camera coordinate system is a coordinate system defined with respect to a location and orientation of the camera that the communication interface is configured to communicate with, and the world coordinate system is a coordinate system defined with respect to a location that is stationary relative to the base of the robot that the communication interface is configured to communicate with.