1. A process comprising: determining a radon transform of the power spectrum of the blurred image; inspecting the power spectrum of the image and determining the direction of the blur by detecting the direction in which a projection of the radon transform of the image's power spectrum displays the most variance; selecting the radon transform of the images power spectrum in the direction of the blur; applying a filter to smooth the spectrum and remove noise; computing key locations of the smoothed spectrum, wherein the key locations include points at peaks and valleys of the spectrum; using the shutter sequence, computing a modulation transfer function (MTF) of the shutter sequence; computing key locations of the MTF; and computing blur extent in the image from the weighted sum of the ratios of the corresponding key locations from the smoothed spectrum and the MTF shutter sequence.