IMAGE DECONVOLUTION OF EXTENDED OBJECTS - A COMPARISON OF THE INVERSE FOURIER AND THE LUCY TECHNIQUES

We have investigated the relative effectiveness of two deconvolution techniques in restoring spherically aberrated Hubble Space Telescope (HST) images. These images were restricted to extended objects (such as planets) of high signal-to-noise. Our reason for pursuing these studies was that one of the deconvolution methods, the Lucy iterative technique, is generally thought to be far superior to the inverse Fourier method. The application of the Lucy algorithm takes considerably more computing time than the Fourier method and is therefore less desirable if computing resources are limited. The principle deficiency of the Lucy method is that it lacks a general stopping mechanism for the iterations-a condition that the Fourier method is not prone to. For the class of objects described above we find that when properly applied the Fourier technique is completely adequate and equivalent to results from the application of the Lucy algorithm. We tested these methods on the basis of many different starting criteria and found that the final restored image was independent of most of the test parameters. Similar tests applied to a Voyager image of Jupiter (that had been blurred to HST resolution and then had Gaussian and readout noise added to it) provided further verification of these results. © 1993 by Academic Press, Inc.