The effective refocusing distance of the light field camera

Nowadays the researches on light field (LF) and synthetic aperture camera have gained rapidly both in theoretical and application fields. However, the widespread analytical model to interpret the principles of digital refocusing still hasnt provided a satisfactory conclusion on the limitation of refocusing or the restriction of depth of field (DOF), which is an inescapable topic in the study of LF applications. In this paper we adopt the canonical 4-D ray space model of LF camera to offer a brief analytical method for the limitation of digital refocusing. By investigating the inner structure and the optical property of the LF camera, we will also derive a quantized assessment of limitation of refocusing theoretically. As for the experiment, we further design validation experiments to test our estimation value just using the consumer-available micro-lens-array (MLA) camera, Lytro1.0. Both the farthest and the closest distance of the refocusing have been verified. In the future, our theoretical work on the limitation of refocusing may play an essential part in the application of LF camera such as depth estimation.