This paper presents a simple image recognition system for the Rh-0 humanoid robot that has been developed in the University Carlos III of Madrid, Spain. This system extracts some basic features from the image that may be used in the robot's navigation and path planning. The simplicity of this system is based on the assumption that the person interacting with the robot is wearing a red T-shirt as well as on some other assumptions. In the paper we describe the vision system's structure and the steps followed in the development of the image recognition system. Experimental results and discussion complete the description of the system. © 2006 Springer-Verlag Berlin Heidelberg.