Comparing direct and indirect interaction in stroke rehabilitation

We explore the differences of direct (DI) vs. indirect (IDI) interaction in stroke rehabilitation. Direct interaction is when the patients move their arms in reaction to changes in the augmented physical environment; indirect interaction is when the patients move their arms in reaction to changes on a computer screen. We developed a rehabilitation game in both settings evaluated by a within-subject study with 10 patients with chronic stroke, aiming to answer 2 major questions: (i) do the game scores in either of the two interaction modes correlate with clinical assessment scores? and (ii) whether performance is different using direct versus indirect interaction in patients with stroke. Our experimental results confirm higher performance in use of DI over IDI. They also suggest better correlation of DI and clinical scores. Our study provides evidence for the benefits of direct interaction therapies vs. indirect computer-assisted therapies in stroke rehabilitation

Determining the Haptic Feedback Position for Optimizing the Targeting Performance on Ultrasonic Tactile Displays

International audienceAlongside questions of how to create haptic effects on displays via alternative hardware, recent work has explored rendering options with respect to haptic effects, i.e. when and where to provide haptic feedback. In particular, recent work by Zhang and Harrison for electrostatic haptic feedback noted that the optimal technique for haptic feedback during interaction is the Fill technique, where haptic effects are rendered at all times when a user's finger is within the bounds of the target. In this paper, we explore whether this result generalizes to an alternative haptic rendering technology that uses ultrasonic vibrations to create haptic sensations, a technique called the " Squeeze Film Effect ". In contrast to prior work, our results indicate that positioning the haptic feedback as a discrete linear stimulus centred on the target provides an optimal trade-off between speed, accuracy, and user preference. We highlight the implications of this work to the generalizability of haptic feedback: Haptic feedback can improve time, errors, and user satisfaction during interaction, but only if the correct form of feedback is used for the specific haptic effect generated by the hardware

Interface design to support situation awareness in virtual puppetry

Virtual Heritage is the use of digital media to reconstruct cultures and cultural artifacts as they are today or as they might have been in the past. The central element is usually a threedimensional computer model of a person, place, or thing. Frequently, these are ancient monuments, temples, homes, and other social spaces (Jacobson, 2008). The goal of Virtual Heritage is to draw viewers into the virtual world and allow them to directly experience the overall context of the environment. This phenomenon is known to researchers as “presence.” It is a long held belief that the increased presence yields better the opportunities for deeper learning (Devine, 2007)

Evaluating tactile feedback and direct vs. indirect stylus input in pointing and crossing selection tasks

We present a pair of experiments that explore the effects of tactile-feedback and direct vs. indirect pen input on pointing and crossing selection tasks. While previous work has demonstrated the validity of crossing as a useful selection mechanism for pen-based computing, those experiments were conducted using an indirect input device- one in which the pen-input and display were separated. We investigate users ’ performance with pointing and crossing interfaces controlled via not only an indirect input device, but also a direct input device- one in which the pen-input and display are co-located. Results show that direct input significantly outperforms indirect input for crossing selections, but the two modalities are essentially equivalent in pointing selection. A small amount of tactile feedback is shown to be beneficial for both pointing and crossing selection, most noticeably in crossing tasks when using direct input where visual feedback is often occluded by a hand or stylus

Touch Amplification for Human Computer Interaction

This thesis proposes a unique approach to haptic feedback, based on a hand-worn electronic device that amplifies the sense of touch. By capturing and reproducing touch elicited vibrations in real time, the feeling of otherwise natural finger-object interactions can be altered, while preserving temporal and spectral properties of the signal that are unique for every interaction and thus impossible to display without sensing and processing in real time. In order to shed light on the physical mechanisms through which such a device can operate, this thesis undertook an empirical investigation of the propagation of touch elicited mechanical vibrations (elastic waves) in the finger, and their dependence on the spatial pathway and frequency of excitation. Next, the thesis proposes a novel touch amplification system informed by these results, and addresses factors affecting the performance of the device, including the stability of the system at high gain levels. The results suggest promising applications in augmented reality and human-computer interaction

Supporting Eyes-Free Human–Computer Interaction with Vibrotactile Haptification

The sense of touch is a crucial sense when using our hands in complex tasks. Some tasks we learn to do even without sight by just using the sense of touch in our fingers and hands. Modern touchscreen devices, however, have lost some of that tactile feeling while removing physical controls from the interaction. Touch is also a sense that is underutilized in interactions with technology and could provide new ways of interaction to support users. While users are using information technology in certain situations, they cannot visually and mentally focus completely during the interaction. Humans can utilize their sense of touch more comprehensively in interactions and learn to understand tactile information while interacting with information technology. This thesis introduces a set of experiments that evaluate human capabilities to understand and notice tactile information provided by current actuator technology and further introduces a couple of examples of haptic user interfaces (HUIs) to use under eyes-free use scenarios. These experiments evaluate the benefits of such interfaces for users and concludes with some guidelines and methods for how to create this kind of user interfaces. The experiments in this thesis can be divided into three groups. In the first group, with the first two experiments, the detection of vibrotactile stimuli and interpretation of the abstract meaning of vibrotactile feedback was evaluated. Experiments in the second group evaluated how to design rhythmic vibrotactile tactons to be basic vibrotactile primitives for HUIs. The last group of two experiments evaluated how these HUIs benefit the users in the distracted and eyes-free interaction scenarios. The primary aim for this series of experiments was to evaluate if utilizing the current level of actuation technology could be used more comprehensively than in current-day solutions with simple haptic alerts and notifications. Thus, to find out if the comprehensive use of vibrotactile feedback in interactions would provide additional benefits for the users, compared to the current level of haptic interaction methods and nonhaptic interaction methods. The main finding of this research is that while using more comprehensive HUIs in eyes-free distracted-use scenarios, such as while driving a car, the user’s main task, driving, is performed better. Furthermore, users liked the comprehensively haptified user interfaces

Expressive feedback from virtual buttons

The simple action of pressing a button is a multimodal interaction with an interesting depth of complexity. As the development of computer interfaces to support 3D tasks evolves, there is a need to better understand how users will interact with virtual buttons that generate feedback from multiple sensory modalities. This research examined the effects of visual, auditory, and haptic feedback from virtual buttons on task performance dialing phone numbers and on the motion of individual buttons presses. This research also presents a theoretical framework for virtual button feedback and a model of virtual button feedback that includes touch feedback hysteresis. The results suggest that although haptic feedback alone was not enough to prevent participants from pressing the button farther than necessary, bimodal and trimodal feedback combinations that included haptic feedback shortened the depth of the presses. However, the shallower presses observed during trimodal feedback may have led to a counterintuitive increase in the number of digits that the participants omitted during the task. Even though interaction with virtual buttons may appear simple, it is important to understand the complexities behind the multimodal interaction because users will seek out the multimodal interactions they prefer

Touch Crossing-Based Selection and the Pin-and-Cross Technique

This thesis focuses on the evaluation, exploration and demonstration of crossing paradigm with touch modality. Under the scenario of crossing selection, the target is selected by stroking through a boundary 'goal' instead of pointing inside a perimeter. We present empirical evidence to validate crossing performance for touch. Inspired by the experimental results, we then develop, evaluate and demonstrate a new unimanual multi-touch interaction space called 'pin-and-cross'. It combines one or more static touches ('pins') with another touch to cross a radial target, all performed with one hand. Our work serves to provide necessary support for the exploration and evaluation of more expressive multi-touch crossing techniques