Efficient restoration of space-variant blurs from physical optics by sectioning with modified Wiener filtering

Digital images blurred by space-variant point-spread functions of uncorrected physical optics may be efficiently restored using Wiener filtering on overlapping subimage frames. Frame size must be tailored to accommodate the displacement-dependent spreading and shifting of physical pointspread functions at large field angles to prevent circular convolution edge effects from corrupting the frame’s central section. We define the section as the nonoverlapping subframe used to construct the composite full-image restoration. Otherwise, if the frame is too small, edge-effect errors may extend into the section, inducing artifacts in the composite restoration. Conversely, if the frame is too large, total restoration processing will be greater than necessary. By adjusting frame size with field displacement, we demonstrate the effective restoration of images blurred by a laboratory-grade spherical lens. Blurred images are simulated and then restored with a modified Wiener filter. Meansquare-error and restoration improvement are reported as a function of field angle and criteria are developed for frame and section size selection.  2002 Elsevier Science (USA). All rights reserved.