TNO Human Factors Virtue: Overview of human factors experiments; concertation meeting September 2002 Michael Holewijn (the Netherlands)

Human Factors 2 Partners BT Exact Technologies:Management Heinrich-Hertz Institut:Real-time algorithms Sony Europe:Hardware systems Heriot-Watt University:3-D computer vision Technical University Delft:Image processing TNO Human Factors:Human Factors

Human Factors 3 User centered design Environment Technical issues Human Factors

Human Factors 4 Background 5 user centered experiments Experiments used a mock- up with the features of the Virtue system Goal: test user specs described from literature (D01) & contribute to requirements final system

Human Factors 5 Experiment 1: Effects of shared virtual background Do subjects perceive a seam in the display? task: information sharing measures: telepresence, information exchange, cohesion, satisfaction, task performance Results: no difference between conditions

Human Factors 6 Experiment 2: Value of stereoscopic visualization and motion parallax Goals: determine if stereoscopy and motion parallax are recognizable? How much freedom of movement is necessary? Delft University’s Panorama system

Human Factors 7 Results: exp stereoscopic visualization and motion parallax Motion parallax is assessed (48%) more often correctly than stereoscopy (25%). Subjects have to have at least 31 degrees moving space in order to notice a difference in motion parallax. Explanations: People have experience watching 2D television and are used to perceive depth based on other cues, such as interposition. Panorama system has a limited range of stereo-scopic and motion parallax effect

Human Factors 8 Experiment 3: Effects of delays / synchronization on subjective measures Goal: Determine user acceptance of desynchronized audio-video signals by reducing the audio delay Conditions: video roundtrip delay fixed at 700 ms audio roundtrip delays: 300, 500 (audio ahead of video), 700 ms Measures:, information exchange, cohesion, satisfaction telepresence, task performance `

Human Factors 9 Results experiment “ Effects of delays / synchronization” No effects of audio delays on any performance measure With delays perceived telepresence was significantly lower

Human Factors 10 Experiment 4: Effects of deviations in selective gaze Goal: to provide information on the gaze deviations allowed Gaze deviations toward A: 0, 5, 10 degrees Gaze deviations B C: 0, 15, 30 degrees Measures: presence communication

Human Factors 11 Results experiment “Effects of deviations in selective gaze” Deviations in gaze toward oneself lead to lower spatial presence than situations without gaze deviations. A gaze deviation for the other two participants is often not visible for the person behind the VIRTUE system. Large deviations (up to 30 degrees) have no effect on perceived presence or group communication.

Human Factors 12 Design implications No seamless background is required to produce a convincing impression of telepresence. Large gaze deviations (up to 30 degrees) have an effect on perceived presence nor on group communication.

Human Factors 13 Design implications Stereoscopy and motion parallax features do not have to be taken into consideration for increasing telepresence. People are used to using different cues to perceive depth. The round-trip delay for audio can be set up to 0.4 s below that for video (audio may be sent up to 400 ms ahead of video). Different set of tasks and more time pressure may show beneficial effects of stereoscopy and motion parallax, and set round-trip delay for audio to 0.3 s below that for video.

Human Factors 14 Goal: to investigate whether and how users adapt their videoconferencing behavior over time Conditions: 4 types of tasks (brainstorm, negotiation, choice, execute) Face-to-face (FF) versus Videoconferencing (VC) 4 times in 2-week intervals Measures of performance task performance communication structure (e.g., # turns, interruptions, pauses) communication content (e.g., questions, answers, support) subjective measures (e.g., presence, cohesion, workload) Experiment 5: Long-term adaptation

Human Factors 15 Conclusions Performance VC = FF Adaptation effect Structure FF > VC: more formal communication in VC No adaptation effect Content VC > FF: more positive expressions in VC FF > VC: more questions and fewer answers in VC VC > FFVC = FFFF > VC Performance Communication structure Communication content VC=video conf. FF= face to face

Human Factors 16 Assessment of final VIRTUE videoconferencing system User requirements & acceptance check (September- October)