We present a fast and robust system for color-based segmentation. The system is based on hierarchical region-growing on a special hexagonal topology. In contrast to common region-growing techniques it is independent of the starting point and the order of processing. It is generally applicable in natural color scenes and algorithmically efficient. The use of local and global information and a new color similarity measure contribute to the robust segmentation results. The system is successfully applied in two difficult applications from the field of autonomous vehicle guidance.