Data are presented from observations of Magical Mirrors, a set of four large public displays with gesture-based interaction installed in downtown Berlin, Germany. The displays show a mirror image of the environment in front of them and react with optical effects to the gestures of the audience. Observations of audience behavior revealed recurring behavioral patterns, like glancing at a first display while passing it, moving the arms to cause some effects, then directly approaching one of the following displays and positioning oneself in the center of the display. This was often followed by positioning oneself in the center of the other displays to explore the possibilities of the different effects, and sometimes by taking photographs or videos. From these observations a framework of interaction with gesture-based public display systems was deduced. It describes the phases of passing by a display, viewing & reacting, subtle interaction, direct interaction, multiple interactions, and follow-up actions. Quantitative data of these behavioral phases was collected by observing 660 passers-by on 2 weekend evenings. This article shows how many passers-by pass the thresholds between these phases. This “Audience Funnel” should provide a framework to encourage systematic investigation of public display systems and enable comparability between different studies.

Digital immersion is moving into public space. Interactive screens and public displays are deployed in urban environments, malls, and shop windows. Inner city areas, airports, train stations and stadiums are experiencing a transformation from traditional to digital displays enabling new forms of multimedia presentation and new user experiences. Imagine a walkway with digital displays that allows a user to immerse herself in her favorite content while moving through public space. In this paper we discuss the fundamentals for creating exciting public displays and multimedia experiences enabling new forms of engagement with digital content. Interaction in public space and with public displays can be categorized in phases, each having specific requirements. Attracting, engaging and motivating the user are central design issues that are addressed in this paper. We provide a comprehensive analysis of the design space explaining mental models and interaction modalities and we conclude a taxonomy for interactive public display from this analysis. Our analysis and the taxonomy are grounded in a large number of research projects, art installations and experience. With our contribution we aim at providing a comprehensive guide for designers and developers of interactive multimedia on public displays.