Yasutake Takahashi Walter Nowak Thomas Wisspeintner Adaptive Recognition of Color-Coded Objects in Indoor and Outdoor Environments. 65-76 2007 RoboCup http://dx.doi.org/10.1007/978-3-540-68847-1_6 conf/robocup/2007 db/conf/robocup/robocup2007.html#TakahashiNW07