Estimation of projected circle centers from array circles and its application in camera calibration

A method of detecting projected circle centers (PCC) based on array circles is proposed. The perspective distortion of projected circle centers could be eliminated from coplanar circles. By utilizing the property of projected coplanar circles, lines connecting PCCs are computed from projective invariant points defined by the projected circles (PCs), and then the PCCs are determined from the intersection of the computed lines. Once PCCs are recovered, the camera could be calibrated from classic method such as Zhang´s. Both synthetic and real data have been used to testify the proposed algorithm and good results have been obtained. The calibration results show that the estmation of projected circle centre bears high stability and accuracy, even when the image noise is massive.