Where physically is the optical center?

A simple and fast method of determining the position of the optical center without any specialized equipment is presented. The position of the optical center is a depth determining parameter in a panoramic depth imaging system [Peer, P., Solina, F., 2002. Panoramic depth imaging: single standard camera approach. Internat. J. Comput. Vision 47 (1/2/3), 149–160; Peer, P., Solina, F., 2005. Multiperspective panoramic depth imaging. In: Computer Vision and Robotics. Nova Science Publishers]. The reconstructed distances correspond well to the actual measured distances on the scene.