We conducted two experiments to investigate how stereoscopy and technologies that allow individual eye contact affect the impression of telepresence in video-conferencing. Telepresence is defined as the degree to which participants of a telemeeting get the impression of sharing space with the remote site. Results revealed, among other things, that stereoscopy increases telepresence and makes videoconferencing more attractive. In addition, we found that reduced eye contact angles enhance the recognizability of individually addressed nonverbal signals. However, a setup that eliminates horizontal and vertical eye contact angles seems to be advantageous only in conferences with more than two persons per site.
This paper deals with factors affecting Communicative Presence in videocommunications. Communicative Presence is defined as the capacity of a system to transfer mutual communicative signals of interlocutors. The experiment the paper reports on examined the effects of various features of videoconferencing systems in terms of several aspects, such as the conferees' feeling of being individually addressed by non-verbal signals (e.g. eye-contact), the flow of conversation, user satisfaction, and the willingness to use videoconferencing systems. One system feature that was systematically varied was the degree of vertical and horizontal eye-contact angles. In order to reduce the horizontal eye-contact angles for the two test subjects acting as conferees at one site of the experimental set-up, two different images (one per conferee) which were in accordance with the perspectives the conferees would have in a similar face-to-face meeting were displayed (“view-per-person” principle). Another feature that was examined was the spatial resolution of the displayed images. The results showed that large eye-contact angles as well as a low resolution decrease the feeling of Communicative Presence. Within the framework of the experiment, the hypothesis concerning the benefits of a view-per-person representation could not be verified.
The introduction of videocommunications via the Integrated Services Digital Network (ISDN) offers the potential of significant changes in the working conditions of a variety of professions including conference interpreters. A study was conducted aiming at identifying the special videocommunications requirements of professional conference interpreters and establishing whether ISDN videotelephony offers a sufficient audio bandwidth and image resolution to support the interpreters in their work. To this aim, a requirements analysis was conducted and four videotelephony systems were set up each implementing a different ISDN combination of audio bandwidth and picture quality. Five professional interpreters took part in the study. Each performed a simultaneous interpretation task of 30 minutes under each of the four conditions (set-ups). Stimulus material to be interpreted consisted of videotapes of conference presentations and TV interviews. Data on the dependent variables (task difficulty, benefits of the picture, sound quality, Social Presence, performance, and acceptance) were collected by means of questionnaires. The most important conclusion is that remote interpreting using ISDN videotelephony is possible only at a cost in terms of both increased fatigue and less satisfaction of the interpreters with their work. Remote interpreting requires at least the image quality that can be provided by a 384 kbit/s transmission rate (until better coding algorithms are available for lower transmission rates) and an audio bandwidth of at least 7 kHz. It is further recommended to conduct a field study with standardized interpreting equipment using more realistic input material.
The paper discusses factors that affect the impression of telepresence in videocommunications. Telepresence is experienced by interlocutors to the extent to which natural visual cues from the remote site are adequately transferred by the medium. The paper reports on two experimental Human Factors studies investigating the effects of various features of videoconferencing systems in terms of, inter alia, the conferees' impression of telepresence as well as user satisfaction and the willingness to use those systems. Within the framework of Experiment 1 the system features that were varied were the scale of representing the conferees (natural vs. reduced size) and the representation of the conferees' surroundings (small vs. large sector of the remote room). In Experiment 2 the system feature being tested was the stereoscopic representation of the conferees. Results showed that both the natural-size representation of conferees as well as the stereoscopic representation increase the impression of telepresence. The expected benefits of a representation of the conferees' surroundings could not be verified. Given a fixed size of the screen, the trade-off between the conferees' size and the representation of surroundings is in favor of the natural size representation.
Telex 185 995 hhi d boecker@ hhi.deThe paper addresses the question whether reproducing motion parallax increases the extent of telepresence in videocommunications. Motion parallax is defined as the change of the view due to the observer's movements. It was hypothesized that reproducing motion parallax (a) leads to more precise depth judgments by providing further depth cues, (b) allows 'interactive viewing', i s . the observer can actively explore the visual scene by changing hisher position, and (c) compensates for stereoscopic "apparent movements". In a Human Factors study, two videoconferencing set-ups providing motion parallax (one stereoscopic and one monoscopic version) were compared with two set-ups (monoscopic and stereoscopic) without motion parallax. Each set-up was used and rated by 32 subjects. The results supported the hypotheses only in part. Even though there was some evidence for more "spatial presence" and for a greater explorability of the scene through motion parallax, the compensation of apparent movements could not be achieved.
INTRODUCTIONhigh degree of telepresence requires a realistic sensory (visual and auditory)-representation of the remote scene including depth cues and communicative signals. This paper concentrates on the effects of the reproduction of motion parallax on spatial presence.
The starting point of the project is the observation that new information and communication technologies (leT) are often introduced without taking into account the requirements of elderly and/or disabled users, resulting in products and services that are hardly usable by those users. A method for identifying enablers for future e-Services is described. In short it identifies usability problems with future interation technologies and map these future interaction technologies to e-Services. The results of investigations using this method allow stakeholders in different stages of the research and development Iifecycle e-Services to spot potential difficulties in the design of user interfaces which could cause elderly or disabled users to experience usability issues.
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