Fundamentals of Wearable Computers and Augmented Reality, 2nd Edition

156 Fundamentals of Wearable Computers and Augmented Reality

7.3 CAMERA POSE TRACKING WITH ROBUST SFM

This section describes a tracking system for markerless AR based on the tracking

via recognition framework. As illustrated in Figure 7.1, the system includes two

main components. The rst component, the ofine stage, takes a video stream as

input and builds a sparse point cloud model of the target environment using robust

SFM. Keypoints are extracted from the point clouds and represented as a set of local

descriptors. Its output is a database of recognizable keypoints along with 3D descrip-

tions of accompanying virtual objects. The second par ...