A primary stage in the analysis of Synthetic Aperture Radar (and other) images, is to produce a segmentation of the image; that is, a division into sub-regions each, hopefully, representing a single object: a field, hedge, wood etc. Producing such a segmentation is made difficult by the high level of speckle inherent in SAR images, and a number of segmentation techniques have been developed. We describe here a methodology for providing objective tests of segmentation algorithms and give representative resulls for one such algorithm.