Distance-Dependent Barcodes for Context-Aware Mobile Applications.

This article introduces the novel concept of distance-dependent barcodes, which provide users with different data based on their scanning distance. These barcodes employ color blending as the key technique to achieve distance-dependence. A simple yet robust encoding scheme is devised accordingly to distinguish between near and far users. Through several experimental results, the proposed technique is shown to be effective (in terms of clear separation between near and far scanners), reliable (as to successful scans), and practical (it can be used in off-the-shelf smartphones). A few representative use cases are then presented to establish distance-dependent barcodes as an enabling technology for context-aware mobile applications. They include casual interactions with public displays, where the role of users is determined based on their distance from a screen, and augmented reality in retail, where distance-dependent barcodes provide information on available goods with different granularities. Finally, distance-dependent barcodes are shown to be user-friendly and effective through a user study.