Resolution versus Speckle Relative to Geologic Interpretability of Spaceborne Radar Images: A Survey of User Preference

A survey was conducted to evaluate user preference for resolution versus speckle relative to the geologic interpretability of spaceborne radar images. Thirteen different resolution/looks combinations were simulated from Seasat synthetic-aperture radar (SAR) data of each of three test sites. The SAR images were distributed with questionnarires for analysis by eighty-five earth scientists. The relative discriminability of geologic targets at each test site for each simulation of resolution and speckle on the images is determined here from a survey of the evaluations. A large majority of the analysts indicate that for most targets a two-look image at the highest simulated resolution is best. For a constant data rate a higher resolution is more important for target discrimination than a greater number of looks. Sand dunes require more looks than other geologic targets. Multiple-look images are preferred over the corresponding single-look image at all resolutions. The number of multiple looks that is optimal for discriminating geologic logic targets is in general inversely related to the simulated resolution.