In this article will be presented the problem of real-time localization for humanoid robots. For this purpose we using a single camera as the only sensor.nbsp In order to obtain fully autonomous robots an accurate localization of the robot in the world is much more than desirable. Moreover, if we can obtain an accurate localization in real-time, than we can use the remaining computational resources to perform other important humanoid robotic tasks such as planning [1], 3D object modeling [2] or visual perception [3].