Depth recovery using defocus blur at infinity

This paper presents a depth recovery technique based on the maximum defocus blur associated with a camera focus setting. The depth-blur relation is formulated by a mathematical model and verified by defocus calibration. Image intensity histogram analysis is used to identify the blur extent. Different from the existing depth from defocus approaches, our method is capable of depth recovery using a single image, possibly up to scale. Experiments on real scene images have demonstrated the feasibility of the proposed method for depth recovery.