Marcel Gavriliu

Sensing techniques for tablet+stylus interaction

We explore grip and motion sensing to afford new techniques that leverage how users naturally manipulate tablet and stylus devices during pen + touch interaction. We can detect whether the user holds the pen in a writing grip or tucked between his fingers. We can distinguish bare-handed inputs, such as drag and pinch gestures produced by the nonpreferred hand, from touch gestures produced by the hand holding the pen, which necessarily impart a detectable motion signal to the stylus. We can sense which hand grips the tablet, and determine the screens relative orientation to the pen. By selectively combining these signals and using them to complement one another, we can tailor interaction to the context, such as by ignoring unintentional touch inputs while writing, or supporting contextually-appropriate tools such as a magnifier for detailed stroke work that appears when the user pinches with the pen tucked between his fingers. These and other techniques can be used to impart new, previously unanticipated subtleties to pen + touch interaction on tablets.

HyperCam: hyperspectral imaging for ubiquitous computing applications

Emerging uses of imaging technology for consumers cover a wide range of application areas from health to interaction techniques; however, typical cameras primarily transduce light from the visible spectrum into only three overlapping components of the spectrum: red, blue, and green. In contrast, hyperspectral imaging breaks down the electromagnetic spectrum into more narrow components and expands coverage beyond the visible spectrum. While hyperspectral imaging has proven useful as an industrial technology, its use as a sensing approach has been fragmented and largely neglected by the UbiComp community. We explore an approach to make hyperspectral imaging easier and bring it closer to the end-users. HyperCam provides a low-cost implementation of a multispectral camera and a software approach that automatically analyzes the scene and provides a user with an optimal set of images that try to capture the salient information of the scene. We present a number of use-cases that demonstrate HyperCams usefulness and effectiveness.

Sensing Tablet Grasp + Micro-mobility for Active Reading

The orientation and repositioning of physical artefacts (such as paper documents) to afford shared viewing of content, or to steer the attention of others to specific details, is known as micro-mobility. But the role of grasp in micro-mobility has rarely been considered, much less sensed by devices. We therefore employ capacitive grip sensing and inertial motion to explore the design space of combined grasp + micro-mobility by considering three classes of technique in the context of active reading. Single user, single device techniques support grip-influenced behaviors such as bookmarking a page with a finger, but combine this with physical embodiment to allow flipping back to a previous location. Multiple user, single device techniques, such as passing a tablet to another user or working side-by-side on a single device, add fresh nuances of expression to co-located collaboration. And single user, multiple device techniques afford facile cross-referencing of content across devices. Founded on observations of grasp and micro-mobility, these techniques open up new possibilities for both individual and collaborative interaction with electronic documents.