Markerless Visual Tracking for Augmented Books

Abstract

An augmented book is an application that augments such multimedia elements as virtual 3D objects, movie clips, or sound clips to a real book using AR technologies. It is intended to bring additional education effects or amusement to users. For augmented books, this paper presents a markerless visual tracking method which recognizes the current page among numerous pages and estimates its 6 DOF pose in real-time. Given an input image by a camera, the tracking method first recognizes a page and performs wide-baseline keypoint matching at the same time. For that purpose,a generic randomized forest (GRF) is proposed which extends the randomized forest (RF) proposed by Lepetit et al. which only performs wide-baseline keypoint matching. The proposed GRF is capable of simultaneous page recognition and wide-baseline keypoint matching. Once a page is recognized, the tracking method executes the page tracking process without page recognition until the page is turned. The page tracking process selects a keyframe of the page adequate for tracking and employs a coarse-to-fine approach. As a result, the tracking method shows robustness to viewpoint and illumination variations and performance of more than 30 fps for augmented books.