Depth from defocus measurement method based on liquid crystal lens

This paper describes a depth from defocus (DFD) method to recover the depth of scene from two images taken by a liquid crystal (LC) lens imaging system. The system is composed of a camera module and an LC lens. The system's focal length is electrically adjusted by the voltages that are applied on the LC lens. We use two images that are taken at maximum positive and negative, respectively, and the LC lens's optical power, to obtain the depth information via DFD. The principle is described and the experimental results are successfully obtained. The method is simple in that it needs not to involve any mechanical lens movements in the imaging system.