Browsing by Author "Jorge, Joaquim"

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    A Comparison of Ray Pointing Techniques for Very Large Displays
    (2009-09-25T17:30:29Z) Jota, Riccardo; Nacenta, Miguel; Jorge, Joaquim; Carpendale, Sheelagh; Greenberg, Saul
    Ray pointing techniques such as laser pointing have long been proposed as a natural way to interact with large and distant displays. However we still do not understand the differences between ray pointing alternatives and how they are affected by the large size of modern displays. We present a study where four different variants of ray pointing are tested for horizontal targeting, vertical targeting and tracing tasks in a room-sized display that covers a large part of the user‟s field of view. Our goal was to better under-stand two factors: control type and parallax under this sce-nario. The results show that techniques based on rotational control perform better for targeting tasks and techniques with low parallax are best for tracing tasks. This implies that ray pointing techniques must be carefully selected de-pending on the kind of tasks supported by the system. We also present evidence on how a Fitts‟s law analysis based on angles can explain the differences in completion time of tasks better than the standard analysis based on linear width and distance.
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    The Continuous Interaction Space: Interaction Techniques Unifying Touch and Gesture On and Above a Digital Surface
    (2011-01-28T18:00:55Z) Jota, Ricardo; Marquardt, Nicolai; Greenberg, Saul; Jorge, Joaquim
    The rising popularity of digital table surfaces has spawned considerable interest in new interaction techniques. Most interactions fall into one of two modalities: 1) direct touch and multi-touch (by hand and by tangibles) directly on the surface, and 2) hand gestures above the surface. The limitation is that these two modalities ignore the rich interaction space between them. To move beyond this limitation, we first contribute a unification of these discrete interaction modalities called the continuous interaction space. The idea is that many interaction techniques can be developed that go beyond these two modalities, where they can leverage the space between them. That is, we believe that the underlying system should treat the space on and above the surface as a continuum, where a person can use touch, gestures, and tangibles anywhere in the space and naturally move between them. Our second contribution illustrates this, where we introduce a variety of interaction categories that exploit the space between these modalities. For example, with our Extended Continuous Gestures category, a person can start an interaction with a direct touch and drag, and then naturally lift off the surface and continue their drag with a hand gesture over the surface. For each interaction category, we implement an example (or use prior work) that illustrates how that technique can be applied. In summary, our primary contribution is to broaden the design space of interaction techniques for digital surfaces, where we populate the continuous interaction space both with concepts and examples that emerge from considering this space as a continuum.
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    Interactive Two-Sided Transparent Displays: Designing for Collaboration
    (2014-01-24) Li, Jiannan; Greenberg, Saul; Sharlin, Ehud; Jorge, Joaquim
    Transparent displays can serve as an important collaborative medium supporting face-to-face interactions over a shared visual work surface. Such displays enhance workspace awareness: when a person is working on one side of a transparent display, the person on the other side can see the other’s body, hand gestures, gaze and what he or she is actually manipulating on the shared screen. Even so, we argue that designing such transparent displays must go beyond current offerings if it is to support collaboration. First, both sides of the display must accept interactive input, preferably by at least touch and / or pen, as that affords the ability for either person to directly interact with the workspace items. Second, and more controversially, both sides of the display must be able to present different content, albeit selectively. Third (and related to the second point), because screen contents and lighting can partially obscure what can be seen through the surface, the display should visually enhance the actions of the person on the other side to better support workspace awareness. We describe a prototype system we built to satisfy these requirements called FACINGBOARD-2, where we concentrate on how its design supports these three collaborative requirements.