I. Introduction
Although the concept of the “paperless office” was proposed a long time ago, physical paper documents are still resilient, even in a digital age, because they have many advantages, such as ease of use, superior readability, and availability. However, the information printed on paper is static, making the information hard to modify and search. On the other hand, mobile devices provide great flexibility and convenience to retrieve and modify digital information anywhere and anytime. However, the small screen makes it frustrating to browse a large amount of information. By augmenting paper documents with digital information, a spatially aware, mobile interaction can overcome the shortcomings of paper documents and mobile devices. A user can move a spatially aware mobile device over a paper document to dynamically visualize the user-focused information within a large workspace that provides the necessary interaction context.