BlindAid, a virtual environment system developed in part for orientation and mobility training of newly, adventitiously, and congenitally blind persons, allows interaction with different virtual structures and objects via auditory and haptic feedback. This research examined whether and how the system might help people who are blind develop orientation and mobility skills within a traditional rehabilitation program. Nine clients at The Carroll Center for the Blind (Newton, MA) explored VEs and performed virtual orientation tasks in addition to their traditional orientation and mobility training. The virtual training gave the participants additional time to learn systematic exploration and orientation strategies and their performance was evaluated using qualitative and quantitative methods. The findings supply strong evidence that practicing with the BlindAid system does enhance traditional orientation and mobility training in these areas.

In this work, we designed an interactive stylus interface for touch-screen devices, the wUbi-Pen haptic stylus. The stylus has functions of providing both vibration and impact with a single actuator, and it is a stand-alone system including its own battery and communication module. We present a new interaction scheme on the graphical user interface (GUI) based on sensory feedback events for clicking, drag-and-drop, moving, sliding, highlighting, and drawing. Experiments evaluating stylus performance indicated that the haptic cues improved precise control of GUI elements. A simple interactive digital sketchbook was also implemented, which provided a variety of haptic feedback while drawing and touching objects.

The generation of multimodal virtual environments for surgical training is complicated by the necessity to develop heterogeneous simulation scenarios such as surgical incision, cauterization, bleeding, and smoke generation involving the interaction of surgical tools with soft biological tissues in real time. While several techniques ranging from rapid but nonphysical geometry-based procedures to complex but computationally inefficient finite element analysis schemes have been proposed, none is uniquely suited to solve the digital surgery problem. In this paper we discuss the challenges facing the field of realistic surgery simulation and present a novel point-associated finite field (PAFF) approach, developed specifically to cope with these challenges. Based upon the equations of motion dictated by physics, this technique is independent of the state of matter, geometry and material properties and permits different levels of detail. We propose several specializations of this scheme for various operational complexities. The accuracy and efficiency of this technique is compared with solutions using traditional finite element methods and simulation results are reported on segmented models obtained from the Visible Human Project.

The extent to which the addition of haptic communication between human users in a shared virtual environment (SVE) contributes to the shared experience of the users has not received much attention in the literature. In this paper we describe a demonstration of and an experimental study on haptic interaction between two users over a network of significant physical distance and a number of network hops. A number of techniques to mitigate instability of the haptic interactions induced by network latency are presented. An experiment to evaluate the use of haptics in a collaborative situation mediated by a networked virtual environment is examined. The experimental subjects were to cooperate in lifting a virtual box together under one of four conditions in a between-groups design. Questionnaires were used to report the ease with which they could perform the task and the subjective levels of presence and copresence experienced. This extends earlier work by the authors to consider the possibility of haptic collaboration under real network conditions with a number of improvements. Using the technology described in this paper, transatlantic touch was successfully demonstrated between the Touch Lab at Massachusetts Institute of Technology, USA and Virtual Environments and Computer Graphics (VECG) lab at University College London (UCL), UK in 2002. It was also presented at the Internet II demonstration meeting in 2002 between University of Southern California and the Massachusetts Institute of Technology.

Computer haptics, an emerging field of research that is analogous to computer graphics, is concerned with the generation and rendering of haptic virtual objects. In this paper, we propose an efficient haptic rendering method for displaying the feel of 3-D polyhedral objects in virtual environments (VEs). Using this method and a haptic interface device, the users can manually explore and feel the shape and surface details of virtual objects. The main component of our rendering method is the “neighborhood watch” algorithm that takes advantage of precomputed connectivity information for detecting collisions between the end effector of a force-reflecting robot and polyhedral objects in VEs. We use a hierarchical database, multithreading techniques, and efficient search procedures to reduce the computational time such that the haptic servo rate after the first contact is essentially independent of the number of polygons that represent the object. We also propose efficient methods for displaying surface properties of objects such as haptic texture and friction. Our haptic-texturing techniques and friction model can add surface details onto convex or concave 3-D polygonal surfaces. These haptic-rendering techniques can be extended to display dynamics of rigid and deformable objects.