Image deblurring by means of defocus

A new method for rapid deblurring (partial deconvolution) is proposed which is based on the physics of coherent image formation. The method uses slightly out-of-focus images in a way that makes the Fresnel diffraction counteract the blurring due to the point-spread function. The resultant deblurring improves spatial resolution in the images and is remarkably insensitive to noise. Successful performance of several variants of this technique is demonstrated using simulated and experimental images. It is anticipated that this method will find applications in medical, astronomical and other imaging problems, as well as in lithography.