An efficient method for monocular depth from defocus

We propose a new method to evaluate the depth from defocus. Using two blurred images we measure the difference of blur level at pixel locations that correspond to intensity discontinuities. The two images are acquired from the same point of view with different focus settings. The proposed algorithm is based on the computation of the ratio of the magnitude of gradients computed from the two images. The resulting algorithm is simple and efficient. Experiments on real confirm the accuracy of the method which can run at video rate.