We address the registration problem for interactive AR applications. Such applications require a real-time registration process. Although the registration problem has received a lot of attention in the computer vision community, it's far from being solved. Ideally, an AR system should work in all environments without the need to prepare the scene ahead of time, and users should be able to walk anywhere they want. In the past, several AR systems have achieved accurate and fast tracking and registration, putting dots over objects and tracking the dots with a camera. We can also achieve registration by identifying features in the scene that we can carefully measure for real-world coordinates. However, such methods restrict the system's flexibility. Hence, we need to investigate registration methods that work in unprepared environments and reduce the need to know the objects' geometry in the scene. We propose an efficient solution to real-time camera tracking for scenes that contain planar structures. We can consider many types of scene with our method. We show that our system is reliable and we can use it for real-time applications. We also present results demonstrating real-time camera tracking on indoor and outdoor scenes.