Automatic Refinement of Foreground Regions for Robot Trail Following

Continuous trails are extended regions along the ground such as roads, hiking paths, rivers, and pipelines which can be navigationally useful for ground-based or aerial robots. Finding trails in an image and determining possible obstacles on them are important tasks for robot navigation systems. Assuming that a rough initial segmentation or outline of the region of interest is available, our goal is to refine the initial guess to obtain a more accurate and detail representation of the true trail borders. In this paper, we compare the suitability of several previously published segmentation algorithms both in terms of agreement with ground truth and speed on a range of trail images with diverse appearance characteristics. These algorithms include generic graph cut, a shape-based version of graph cut which employs a distance penalty, Grab Cut, and an iterative superpixel grouping method.