Abstract
This paper addresses the calibration accuracy of a TV camera parameter, i.e., the principal distance. Fiducial marks on a grid plane are translated in the direction vertical to the plane, and the parameter is calibrated from the fiducial-mark image coordinates by using a direct nonlinear minimization. Considering the propagation from the image coordinates measurement errors, we examine the errors of the calibrated parameters and those of the visual angles in 3D space from cameras. Thus, an optimal setup condition with minimum visual-angle error was found among various fiducial mark setups. The errors in the optimal condition are also shown by figures : it enables us to estimate approximate values for any cameras with different principal distances.
