ABSTRACT
We present HapTable; a multi-modal interactive tabletop that allows users to interact with digital images and objects through natural touch gestures, and receive visual and haptic feedback accordingly. In our system, hand pose is registered by an infrared camera and hand gestures are classified using a Support Vector Machine (SVM) classifier. To display a rich set of haptic effects for both static and dynamic gestures, we integrated electromechanical and electrostatic actuation techniques effectively on tabletop surface of HapTable, which is a surface capacitive touch screen. We attached four piezo patches to the edges of tabletop to display vibrotactile feedback for static gestures. For this purpose, the vibration response of the tabletop, in the form of frequency response functions (FRFs), was obtained by a laser Doppler vibrometer for 84 grid points on its surface. Using these FRFs, it is possible to display localized vibrotactile feedback on the surface for static gestures. For dynamic gestures, we utilize the electrostatic actuation technique to modulate the frictional forces between finger skin and tabletop surface by applying voltage to its conductive layer. To our knowledge, this hybrid haptic technology is one of a kind and has not been implemented or tested on a tabletop. It opens up new avenues for gesture-based haptic interaction not only on tabletop surfaces but also on touch surfaces used in mobile devices with potential applications in data visualization, user interfaces, games, entertainment, and education. Here, we present two examples of such applications, one for static and one for dynamic gestures, along with detailed user studies. In the first one, user detects the direction of a virtual flow, such as that of wind or water, by putting their hand on the tabletop surface and feeling a vibrotactile stimulus traveling underneath it. In the second example, user rotates a virtual knob on the tabletop surface to select an item from a menu while feeling the knob's detents and resistance to rotation in the form of frictional haptic feedback.
ABSTRACT
Many computer graphics applications must fragment freehand curves into sets of prespecified geometric primitives. For example, sketch recognition typically converts hand-drawn strokes into line and arc segments and then combines these primitives into meaningful symbols for recognizing drawings. However, current fragmentation methods' shortcomings make them impractical. For example, they require manual tuning, require excessive computational resources, or produce suboptimal solutions that rely on local decisions. DPFrag is an efficient, globally optimal fragmentation method that learns segmentation parameters from data and produces fragmentations by combining primitive recognizers in a dynamic-programming framework. The fragmentation is fast and doesn't require laborious and tedious parameter tuning. In experiments, it beat state-of-the-art methods on standard databases with only a handful of labeled examples.
ABSTRACT
PURPOSE: A unique case of retinitis pigmentosa (RP) associated with bilateral disc edema and unilateral macular hole is presented. METHODS: A 49-year-old woman, a known RP patient, was found to have bilateral disc edema and a macular hole in the left eye during routine clinical examination. Fluorescein angiography revealed hyperfluorescent leakage of the optic nerve head significantly OD and minimally OS. There was staining in the macular regions which was consistent with retinal pigment epithelium atrophy OD and cystoid macular edema (CME) OS. Cerebrospinal fluid pressure and examination by lumbar puncture was normal. Disc edema spontaneously decreased bilaterally during follow-up. DISCUSSION: Bilateral disc edema was thought to be secondary to inflammation caused by rapid degeneration of photoreceptors and retinal pigment epithelium and macular hole was secondary to CME. CONCLUSIONS: Inflammatory response in the course of retinitis pigmentosa may result in disc edema and cystoid macular edema, which may further progresses to macular hole.
