28 3 Click the Change display button to display the through image. Confirm that Meas. value Z is within 400 ± 5 mm and visually check that the optical axis of the 3D vision sensor is perpendicular to the plane of the plate. Refer to the figure on the right for the posture of the camera calibration target. After you check the above, click the Change display button once again to return to the freeze image display. 4 Click the Var. check button to display the results of the geometric variation check in the Geometric var. check result area.