Papers by Sharif Razzaque
2007 IEEE Virtual Reality Conference, 2007
Page 1. MACBETH: The avatar which I see before me and its movement toward my hand1 Eric Burns Uni... more Page 1. MACBETH: The avatar which I see before me and its movement toward my hand1 Eric Burns University of North Carolina, Chapel Hill [email protected] Sharif Razzaque InnerOptic Technologies, Inc. [email protected] ...
Two studies used virtual environments (VEs) to examine the role of simulated motion frequency in ... more Two studies used virtual environments (VEs) to examine the role of simulated motion frequency in visually-induced motion and simulator sickness (SS). Predictions were derived from the "crossover" hypothesis, which suggests that restricting simulated motion frequency in the region where conflicting motion cues to the visual and vestibular self-motion systems are readily detected (around 0.07 Hz) should reduce SS. Results from
2007 IEEE Virtual Reality Conference, 2007
Page 1. MACBETH: The avatar which I see before me and its movement toward my hand1 Eric Burns Uni... more Page 1. MACBETH: The avatar which I see before me and its movement toward my hand1 Eric Burns University of North Carolina, Chapel Hill [email protected] Sharif Razzaque InnerOptic Technologies, Inc. [email protected] ...
CHI '03 extended abstracts on Human factors in computer systems - CHI '03, 2003
... ABSTRACT This paper presents a technique to add the tactile cues of real buttons to virtual b... more ... ABSTRACT This paper presents a technique to add the tactile cues of real buttons to virtual buttons displayed on mobile devices with touch screens. When the user's finger is on the display, tactile feedback coveys a feeling of button location and activation. ...
Abdominal Ultrasound for Surgeons, 2014
IEEE Virtual Reality, 2003. Proceedings., 2003
Previous research has shown that even low end-to-end latency can have adverse effects on performa... more Previous research has shown that even low end-to-end latency can have adverse effects on performance in virtual environments (VE). This paper reports on an experiment investigating the effect of latency on other metrics of VE effectiveness: physiological response, simulator sickness, and self-reported sense of presence. The VE used in the study includes two rooms: the first is normal and non-threatening; the second is designed to evoke a fear/stress response. Participants were assigned to either a low latency (~50 ms) or high latency (~90 ms) group. Participants in the low latency condition had a higher self-reported sense of presence and a statistically higher change in heart rate between the two rooms than did those in the high latency condition. There were no significant relationships between latency and simulator sickness
Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention, 2012
A novel approach to the problem of locating and recognizing anatomical structures of interest in ... more A novel approach to the problem of locating and recognizing anatomical structures of interest in ultrasound (US) video is proposed. While addressing this challenge may be beneficial to US examinations in general, it is particularly useful in situations where portable US probes are used by less experienced personnel. The proposed solution is based on the hypothesis that, rather than their appearance in a single image, anatomical structures are most distinctively characterized by the variation of their appearance as the transducer moves. By drawing on recent advances in the non-linear modeling of video appearance and motion, using an extension of dynamic textures, successful location and recognition is demonstrated on two phantoms. We further analyze computational demands and preliminarily explore insensitivity to anatomic variations.
IEEE Proceedings. VR 2005. Virtual Reality, 2005., 2005
To compare and evaluate locomotion interfaces for users who are (virtually) moving on foot in VEs... more To compare and evaluate locomotion interfaces for users who are (virtually) moving on foot in VEs, we performed a study to characterize task behavior and task performance with different visual and locomotion interfaces. In both a computer-generated environment and a corresponding real environment, study participants walked to targets on walls and stopped as close to them as they could without making contact.
ACM SIGGRAPH 2002 conference abstracts and applications on - SIGGRAPH '02, 2002
A common metric of VE quality is presence the degree to which the user feels like they are in t... more A common metric of VE quality is presence the degree to which the user feels like they are in the virtual scene as opposed to the real world. Presence is important for many VE applications [Hodges et al. 1994]. Since presence is a subjective condition, it is most commonly ...
Redirected Walking, a new interactive locomotion technique for virtual environments (VEs), captur... more Redirected Walking, a new interactive locomotion technique for virtual environments (VEs), captures the benefits of real walking while extending the possible size of the VE. Real walking, although natural and producing a high subjective sense of presence, limits virtual environments to the size of the tracked space. Redirected Walking addresses this limitation by interactively and imperceptibly rotating the virtual scene about the user. The rotation causes the user to walk continually toward the furthest wall of the lab without noticing the rotation. We implemented the technique using stereo graphics and 3D spatialized audio. Observations during a pilot study suggest that the technique works: Redirected Walking causes people to change their real walking direction without noticing it, allows for larger VEs, and does not induce appreciable simulator sickness.
Presence: Teleoperators and Virtual Environments, 2005
This paper presents an experiment investigating the impact of behavior and responsiveness on soci... more This paper presents an experiment investigating the impact of behavior and responsiveness on social responses to virtual humans in an immersive virtual environment (IVE). A number of responses are investigated, including presence, copresence, and two physiological responses-heart rate and electrodermal activity (EDA). Our findings suggest that increasing agents' responsiveness even on a simple level can have a significant impact on certain aspects of people's social responses to humanoid agents.
Presence: Teleoperators and Virtual Environments, 2006
A virtual environment (VE) user's avatar may penetrate virtual objects. Some VE designers pr... more A virtual environment (VE) user's avatar may penetrate virtual objects. Some VE designers prevent visual interpenetration, assuming that prevention improves user experience. However, preventing visual avatar interpenetration causes a discrepancy between visual and proprioceptive ...
Applied Psychophysiology and Biofeedback, 2005
A common measure of effectiveness of a virtual environment (VE) is the amount of presence it evok... more A common measure of effectiveness of a virtual environment (VE) is the amount of presence it evokes in users. Presence is commonly defined as the sense of being there in a VE. There has been much debate about the best way to measure presence, and presence researchers need and have sought a measure that is reliable, valid, sensitive, and objective. We hypothesized that to the degree that a VE seems real, it would evoke physiological responses similar to those evoked by the corresponding real environment, and that greater presence would evoke a greater response. To examine this, we conducted four experiments, each of which built upon findings that physiological measures in general, and heart rate in particular, are reliable, valid, sensitive, and objective presence measures. The experiments compare participants' physiological reactions to a nonthreatening virtual room and their reactions to a stressful virtual height situation. We found that change in heart rate satisfied our requirements for a measure of presence, change in skin conductance did to a lesser extent, and that change in skin temperature did not. Moreover, the results showed that significant increases in heart rate measures of presence appeared with the inclusion of a passive haptic element in the VE, with increasing frame rate (30 FPS > 20 FPS > 15 FPS) and when end-to-end latency was reduced (50 ms > 90 ms).
International Journal of …, 2007
AbstractWhen a virtual environment system prevents a user's avatar hand from penetrating vi... more AbstractWhen a virtual environment system prevents a user's avatar hand from penetrating virtual objects, the seen and felt positions of the hand separate. We propose a new method for reducing this position discrepancy as quickly as possible without introducing perceptible ...
. A participant who believes he is aiming at the virtual game board directly in front of him.
Proceedings of the …, May 30, 2002
This paper describes a method for allowing people to virtually move around a CAVE��� without ever... more This paper describes a method for allowing people to virtually move around a CAVE��� without ever having to turn to face the missing back wall. We describe the method, and report a pilot study of 28 participants, half of whom moved through the virtual world using a hand-held controller, and the other half used the new technique called'Redirected Walking in Place'(RWP). The results show that the current instantiation of the RWP technique does not result in a lower frequency of looking towards the missing wall. ...
Lambeosaurine hadrosaurs are duck-billed dinosaurs known for their large head crests, which resea... more Lambeosaurine hadrosaurs are duck-billed dinosaurs known for their large head crests, which researchers hypothesize were resonators for vocal calls. This paper describes the motivation and process of iteratively designing a musical instrument and interactive sound installation based on imagining the sounds of this extinct dinosaur. We used scientific research as a starting point to create a means of sound production and resonator, using a 3D model obtained from Computed Topology (CT) scans of a Corythosaurus skull and an endocast of its crest and nasal passages. Users give voice to the dinosaur by blowing into a mouthpiece, exciting a larynx mechanism and resonating the sound through the hadrosaur's full-scale nasal cavities and skull. This action allows an embodied glimpse into an ancient past. Users know the dinosaur through the controlled exhalation of their breath, how the compression of their lungs leads to a whisper or a roar.
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Papers by Sharif Razzaque