In a system for segmenting a pixel based image, pixels containing image boundaries are identified. The image boundaries are then fattened by repeatedly adding fattening rows of pixels to the pixels containing boundaries to separate the remaining pixels into separate segments. The separate segments are then grown back to their original size before the boundaries were fattened. This operation has the effect of linking the boundaries together to separate the image into segments and to extend incomplete boundaries into complete boundaries around segments in the image.