We can touch things, and our senses tell us when our hands are touching something. But most computer input devices cannot detect when the user touches or releases the device or some portion of the device. Thus, adding touch sensors to input devices offers many possibilities for novel interaction techniques. We demonstrate the TouchTrackball and the Scrolling TouchMouse, which use unobtrusive capacitance sensors to detect contact from the user's hand without requiring pressure or mechanical actuation of a switch. We further demonstrate how the capabilities of these devices can be matched to an implicit interaction technique, the On-Demand Interface, which uses the passive information captured by touch sensors to fade in or fade out portions of a display depending on what the user is doing; a second technique uses explicit, intentional interaction with touch sensors for enhanced scrolling. We present our new devices in the context of a simple taxonomy of tactile input technologies. Final...

Subjects made roughness judgments of textured surfaces made of raised elements, while holding stick-like probes or through a rigid sheath mounted on the fingertip. These rigid links, which impose vibratory coding of roughness, were compared with the finger (bare or covered with a compliant glove), using magnitude-estimation and roughness differentiation tasks. All end effectors led to an increasing function relating subjective roughness magnitude to surface interelement spacing, and all produced above-chance roughness discrimination. Although discrimination was best with the finger, rigid links produced greater perceived roughness for the smoothest stimuli. A peak in the magnitude-estimation functions for the small probe and a transition from calling more sparsely spaced surfaces rougher to calling them smoother were predictable from the size of the contact area. The results indicate the potential viability of vibratory coding of roughness through a rigid link and have implications for teleoperation and virtual-reality systems. Perceived texture is a multidimensional concept that includes roughness, among many other percepts relating to the distribution of elements on a surface (see Hollins, Faldowski, Rao, & Young, 1993; Loomis & Lederman,

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People can perceive a number of spatial and other prop-erties of objects, without the benefit of vision, simply by wielding and hefting the objects. A variety of recent ex-periments are reported, showing that in this kind of touch-ing, which is closely connected with the states of muscles, the nervous system cleverly exploits the physics of rota-tions. For most people, touch refers to a type of experience they have when their hands move over an object's surface, such as the glossy cover of this issue of the American Psychologist, or when an object contacts their skin, such as a fly alighting on a bare arm in the summertime. There is a form of touch, however, that is perhaps much more commonplace than either of the two forms just mentioned but that usually goes unnoticed. It

This paper presents an intelligent adaptive system for the integration of haptic output in graphical user interfaces. The system observes the user’s actions, extracts meaningful features, and generates a user and application specific model. When the model is sufficiently detailled, it is used to predict the widget which is most likely to be used next by the user. Upon entering this widget, two magnets in a specialized mouse are activated to stop the movement, so target acquisition becomes easier and more comfortable. Besides the intelligent control system, we will present several methods to generate haptic cues which might be integrated in multimodal user interfaces in the future.

In four experiments, we tested whether haptic comparison of curvature ranging from �4/m to +4/m is qualitatively the same for static and for dynamic touch. In Experiments 1 and 3, we tested whether static and dynamic curvature discrimination are based on height differences, attitude (slope) differences, curvature differences, or a combination of these geometrical variables. It was found that both static and dynamic haptic curvature discrimination are based on attitude differences. In Experiments 2 and 4, we tested whether this mechanism leads to errors in the comparison of stimuli with different lengths for static and dynamic touch, respectively. If the judgments are based on attitude differences, subjects will make systematic errors in these comparisons. In both experiments, we found that subjects compared the curvatures of strips of the same length veridically, whereas they made systematic errors if they were required to compare the curvatures of strips of different lengths. Longer stimuli were judged to be more curved than shorter stimuli with the same curvature. We conclude that similar mechanisms underlie static and dynamic haptic curvature comparison. Moreover, additional data comparison showed that static and dynamic curvature comparison is not only qualitatively, but also quantitatively similar. We are grateful to the Netherlands Organization for Scientific Research (NWO) for funding this project. We thank Heino Blanckaert,

This is the second part of a two-part paper that develops a method for the automatic conversion of images from visual to tactile form. In Part I, a variety of topics were reviewed including issues in human factors, access technology for tactile graphics production, and image processing. In this part, the material presented in the first part is used to motivate, develop and support the methods used in the development of a prototype visual-to-tactile translator called the TACTile Image Creation System (TACTICS). The specific choices made in the design of the system are discussed and justified, including selection of software platform, tactile output format, tactile image creation procedure, aggregate image processing sequences used, and principles from the discipline of psychophysics. The results of four experiments on tactile image discrimination, identification and comprehension are reported and discussed, and future directions in this area are proposed. Keywords--- blindness, image p...

Static haptic discrimination of the curvature of convex, concave, or straight 20-cm-long strips was investigated for nine placements on the hand. In one condition, the strips were touched with the palmar side of the hand, and in the other condition, with the dorsal side. The influence of the lengths of the strips, and thus of contact lengths, was also investigated. For all placements, discrimination was poorer in the dorsal than in the palmar condition, owing to poorer cutaneous resolution on the dorsal side of the hand (the kinesthetic stimulation was the same in both conditions). Thus cutaneous stimulation is important. In both experiments, performance appeared to depend primarily on contact length. Moreover, the discrimination thresholds for all different placements and contact lengths followed the same trend. We conclude that in these experiments the effective stimulus for the discrimination of curved strips is the total difference of local surface attitude—that is, the slope difference over the far ends of the stimulus. The authors are grateful to the Netherlands Organization for Scientific Research (NWO) for funding this project. We thank Susan te Pas, Irene Hoitink, and Ronald Burger for acting as observers, and Sheila McNab, whose critical comments have improved the language style of

This paper describes a series of studies involving a haptic device which can display virtual textures and 3D objects. The device has potential for simulating real world objects and assisting in the navigation of virtual environments (VEs). Three experiments investigated: (a) whether previous results from experiments using real textures could be replicated using virtual textures

There are many interactions possible between performer, (electronic) system and audience, involving various modes of communication. In this paper, a concise overview and theoretic fiamework based on research mainly carried out in the HCI field (Human-Computer Interaction) is described, illustrated with a research project in musical performance and interactive technology. The approach described focuses on the physical interaction between people and systems, rather then the interactive behaviour as a result of machine cognition.