Fig. 1.
(color online) (a), (b): Our color marker seen at a distance of 1 meter and of 6 meters respectively. The figures shows a 121 × 121 pixel subimage cropped from the original 640 × 480 pixel image. Superimposed are the locations of the 4 pixels of a “probe” placed at the center of the marker's image. Note the probe's size is the same for the two images, and that correct detection is attained in both cases. (c): The color marker region is segmented (shown in yellow) after detection.