The Iterative refocus command line utility can be used to sharpen images acquired by a defocused camera, blurred with gaussian or any combination of these degradations. In cases of severe blur it produces much better results than plug-ins such as sharpen or unsharp mask. This utility works only with PNM image format (PPM, PGM) Use `refocit -h' for help. There are a few nice features of this utility, especially adaptive/static area smoothing used to remove the so called "ringing" effect introduced by edges in the image and effects introduced by noise. Two boundary conditions can be used (mirror boundaries / periodical boundaries). The algorithm is based on finding the minimum of the error function using Hopfield neural network. There are a few NOT nice features of this utility as well, namely its memory and CPU requirements. If you have any problems or requests please mail me. Lukas Kunc --- Thanks to Ernst Lippe for making his Refocus Gimp plug-in and all authors of the GIMP.