Recovering depth from a single image using spectral energy of the defocused step edge gradient

Obtaining the distance of an object using image capture devices is a convenient and practical approach for intelligent 3D technology. “Depth from defocus” is one of the recovery methods, which has the advantage of using only a single static viewpoint. In this paper, a new method is proposed to represent the defocus blur amount by the spectral energy of the point spread function for depth recovery in a single image. Different from the previous depth from defocus methods, our intuitive approach identifies the blur amount effectively without modeling the defocus blur kernel, and has a high quality of recovery in theory. Experiments using an uncalibrated commercial digital camera have validated the proposed depth recovery technology and shown a considerably good extent of accuracy.