Patent ID: 7613361

Claim:
An information processing method for calculating a position of a marker provided upon an object in an object coordinate system using the object as a reference, the information processing method comprising: an object position-and-orientation information obtaining step for obtaining position and orientation information of the object; a first image input step for inputting a first image from a bird's-eye view imaging unit, photographed from a bird's-eye view of the object in a world coordinate system; a detecting step for detecting the marker from the first image and obtaining a real value of an image coordinate of the detected marker; an image coordinate calculating step for calculating an ideal value of the image coordinate of the marker based on the position and orientation information of the object in the world coordinate system and a state vector representing the position of the marker in the object coordinate system; a correction value calculating step for calculating a correction value of the state vector based on a difference between the real value and the ideal value of the image coordinate of the marker; and a marker position calculating step for calculating the position of the marker in the object coordinate system by correcting the state vector representing the position of the marker in the object coordinate system with the correction value.