Patent ID: 7657065

Claim:
A marker placement information estimating method for an information processing device to estimate spatial placement information of a plurality of markers present within space under a geometric constraint, the marker placement information estimating method comprising: a marker detecting step for detecting markers from a photographed image including markers taken by an imaging unit; a constraint condition setting step for setting a constraint condition of markers; a marker projected position calculating step, performed by a marker projected position calculation unit of the information processing device, for calculating a projected position where a marker is projected on an image surface based on an approximate value of a position and orientation of the imaging unit used to take the photographed image and an approximate value of placement information of the marker; a correction value calculating step for calculating a first correction value for correcting the placement information of the plurality of markers and a second correction value for correcting the position and orientation of the imaging unit used to take the photographed image so as to reduce a sum of error between a position of the marker on the image surface detected in the marker detecting step and the projected position of the marker on the image surface obtained in the marker projected position calculating step, the first correction value satisfying the constraint condition of markers set in the constraint condition setting step; a placement information correcting step for correcting the placement information of the plurality of markers based on the first correction value obtained in the correction value calculating step; and a repeated calculating step for calculating the placement information of the plurality of markers by repeatedly performing the marker projected position calculating step, the correction value calculating step, and the placement information correcting step using the corrected placement information of the plurality of markers and a corrected approximated value of the position and orientation of the imaging unit instead of the approximate value of placement information of the marker and the approximate value of the position and orientation of the imaging unit, wherein the corrected approximated value of the position and orientation of the imaging unit is calculated based on the second correction value, and wherein the repeated calculating step is repeatedly performed until a convergence requirement is met for reducing the sum of the error between the position of the marker on the image surface detected in the marker detecting step and the projected position of the marker on the image surface obtained in the marker projected position calculating step.