Video Conferencing - not that old, not yet truly faithful

Video conferencing is reaching out to everyone, including the desktop. Still I am often confronted with the fact that video conferencing has been “the NEXT big thing” for more than a decade, and has yet to become a truly popular means of communication (like, for instance, the mobile phone). Researchers have found that there are a few problems - primarily psychological - that may explain the slow penetration of video conferencing into our lives, and also the reluctance of many users to add video into their communication-filled lives.

One of the problems highlighted by many researchers was the quality of the video  (image size, frame rate, bit rate, etc.). Before the long-awaited HD became a reality, low resolution video conferencing was very far from supplying a close-to-real experience, and many of the advantages of using a video system were lost. This, of course, is not a real problem anymore, particularly with Telepresence.

High definition Telepresence-like video conference. Source: LifeSize.

Now we move onto the next problem, the “real” problem - maintaining spatial faithfulness. Spatial faithfulness is a term used to describe how attention cues, such as gaze and gesture, are transmitted over virtual space. For more than four decades, research has shown that non-verbal cues, such as gaze, gesture, and body posture, convey a lot of information which helps us conduct effective conversations with our peers.

Albert Mehrabian and others have shown that what we verbally communicate only explains roughly 7% of the impression we leave. The other 93% of communication is attributed to non-verbal cues. This means that if a video conference system does not preserve these cues, the impressions in the conference are at risk.

The limits of a single viewpoint

Most video conferencing systems use a single camera. This means that everyone shares the same view, and so everyone shares the same perspective, without any ability to direct non-verbal cues only at a certain participant. Therefore, important non-verbal cues like gaze and gesture are almost completely lost. Therefore simple tasks in real-life conferences, such as determining whether the speaker is looking at you when he is asking a particular question, are becoming complicated, if not impossible. Even the latest Telepresence systems, which use up to three cameras and screens, still use the same concept of a shared perspective and consequently do not address this issue at all.

Maintaining eye contact

Another part of the challenge to maintain spatial faithfulness is solving the gaze parallax problem. Research has shown that gaze (eye contact) is one of the most important non-verbal cues responsible for monitoring the other participants, regulating the conference and expressing feelings and attitudes. However in many cases, especially when using a low-cost video conferencing system with a simple webcam as a camera, the positioning of the camera (usually on the top of the screen) creates a big difference between the actual gaze and the perceived gaze. In order to look at the screen, the participant must look down, which makes his gaze behavior become totally different than what was intended.

The gaze parallax problem. Source: CeMNet SmartSpace

Milton Chen (pdf) has shown that the correct placement for cameras is at the position of the eyes and they can be up to five degrees higher before the gaze parallax is perceived. Most video conferencing systems, even the latest and greatest, do not comply with these restrictions. However Telepresence, for instance,  uses strict camera positioning help with eliminating the gaze parallax and improving “in-person realism”.

Interesting work has been continuing; both in the industry and academy; to try and come up with a truly spatially faithful video conferencing system: one that preserves the non-verbal cues as much as possible (see Multiview by David Nguyen for a good example). Just as high definition systems are becoming popular and solve one of the barriers for using video conferencing, hopefully innovative concepts and “out of the box” ideas for solving the other barriers mentioned above will soon influence commercial video conferencing systems.

Old Faithful (CC)

Having true spatial faithful video conference systems will enable video conferences to become not only an important and effective means of communication, but also something for the masses. Until then I will continue to preach my preaching, for all the good reasons of course. The next big thing is right around the corner. Use your video conference systems to take a look…