Dynamic registration correction in augmented-reality systems

This paper addresses the problem of correcting visual registration errors in video-based augmented-reality systems. Accurate visual registration between real and computer-generated objects in combined images is critically important for conveying the perception that both types of object occupy the same 3-dimensional (3D) space. To date, augmented-reality systems have concentrated on simply improving 3D coordinate system registration in order to improve apparent (image) registration error. This paper introduces the idea of dynamically measuring registration error in combined images (2D error) and using that information to correct 3D coordinate system registration error which in turn improves registration in the combined images. Registration can be made exact in every combined image if a small video delay can be tolerated. Our experimental augmented-reality system achieves improved image registration, stability, and error tolerance from tracking system drift and jitter over current augmented-reality systems. No additional tracking hardware or other devices are needed on the user's head-mounted display. Computer-generated objects can be "nailed" to real-world reference points in every image the user sees with an easily-implemented algorithm. Dynamic error correction as demonstrated here will likely be a key component of future augmented-reality systems.