Estimation of camera parameters from arbitrary parallelograms

A novel method is introduced to estimate the camera parameters when there is no useful information in the scene but in which two or more parallelograms exist. First, the proposed method acquires the infinite homography by rectification of the imaged parallelograms instead of the general method that uses vanishing point correspondences directly. Due to this peculiar approach, the additional constraints that arise from the parallelograms can be acquired. Second, the infinite homography estimated together with the additional constraints is applied to the calibration of a camera. Owing to the effect of the additional constraints, more accurate estimation results can be acquired. Moreover, even if the number of vanishing points induced from parallelograms is three, the infinite homography and, consequently, camera parameters can be computed without the need for an estimation of the fundamental matrix that requires many point correspondences between the views for accuracy.