Adaptive scale selection for multiresolution defocus blur estimation

This paper presents a new method for defocus blur estimation using a single image. The proposed method exploits the ratio of gradient magnitude images computed at multiple scales, using the scale-space theory to estimate the number of reliable scales. Experimental results on synthetic and real images show that the proposed method is robust to noise, edge mis-localization and neighboring edge interference. We also show a new application of blur estimation algorithms to perform image re-targeting algorithms, leading to in-focus object preservation.