For solving the task successfully and instantly on mobile phones, we propose a method for robust segmentation based on a marker target with a structured background. A checkerboard background is chosen to allow segmentation of arbitrarily coloured object Sina robust manner(seeFigure 1). The marker target itself can be detected efficiently using readily available marker tracking software,likeStudierstube or ARToolkitPlus2. Moreover, the marker itself has a fixed known size, which enables us to accurately measure