A neural network model of boundary segmentation and surface representation is developed to process images containing range data gathered by a s y n thetic aperture radar (SAR) sensor. The boundary and surface processing are accomplished by an improved Boundary Contour System (BCS) and Feature Contour System (FCS), respectively, t h a t h a ve been derived from analyses of perceptual and neurobiological data. BCS/FCS processing makes structures such as motor vehicles, roads, and buildings more salient and interpretable to human observers than they are in the original imagery. Early processing by ON cells and OFF cells emb e d d e d i n s h unting centersurround network models preprocessing by lateral geniculate nucleus (LGN). Such preprocessing compensates for illumination gradients, normalizes input dynamic range, and extracts local ratio contrasts. ON cell and OFF cell outputs are combined in the BCS to de ne oriented lters that model cortical simple cells. Pooling ON and OFF outputs at simple cells overcomes complementary processing de ciencies of each c e l l t ype along concave and convex contours, and enhances simple cell sensitivity to image edges. Oriented lter outputs are recti ed and outputs sensitive to opposite contrast polarities are pooled to de ne complex cells. The complex cells output to stages of shortrange spatial competition (or endstopping) and orientational competition among hypercomplex cells. Hypercomplex cells activate long range cooperative bipole cells that begin to group image boundaries. Nonlinear feedback b e t ween bipole cells and hypercomplex cells segments image regions by cooperatively completing and regularizing the most favored boundaries while suppressing image noise and weaker boundary groupings. Boundary segmentation is performed by three copies of the BCS at small, medium, and large lter scales, whose subsequent i n teraction distances covary with the size of the lter. Filling-in of multiple surface representations occurs within the FCS at each scale via a boundary-gated di usion process. Di usion is activated by the normalized LGN ON and OFF outputs within ON and OFF lling-in domains. Di usion is restricted to the regions de ned by gating signals from the corresponding BCS boundary segmentation. The lled-in opponent O N and OFF signals are subtracted to form double opponent surface representations. These surface representations are shown by a n y of three methods to be sensitive to both image ratio contrasts and background luminance. The three scales of surface representation are then added to yield a nal multiple-scale output. The BCS and FCS are shown to perform favorably in comparison to several other techniques for speckle removal.