Mobile 3-D, Part II: Music to One's Eyes?

Mobile 3-D, Part II: Music to One’s Eyes?

This is part 2 of a two-part series by Mark Schubin, a multiple Emmy Award-winning SMPTE Fellow who has worked professionally in TV since 1967. Read Part 1 here.

In 1908, Camille Saint-Saëns composed what was probably the first film score. What does that have to do with mobile 3-D? It could be a solution (of markschubin2 sorts) to the infinity-interpupillary problem.

Any form of stereoscopic 3-D entertainment must deal with three categories of issues. Technical issues include the delivery of two motion-picture streams instead of one, alignment of dual imagery in both time and space, and mechanisms for getting the correct view–and only the correct view–to each eye.

Then there are program-production issues, including where to make different objects appear (in front of, at, or behind the screen) and how else to make use of the depth axis. When Alfred Hitchcock shot Dial M for Murder in 3-D, he was shocked to discover how barren the sets looked when he viewed the first rushes stereoscopically. Many more props had to be added before the experienced director was satisfied that the depth was properly filled.

The Society of Motion-Picture and Television Engineers (SMPTE) devoted an entire webcast of its Professional Development Academy (PDA) in June of 2009 to the subject, “Producing Stereoscopic Content: What Makes Great 3-D Great and What Can Go Wrong.” How, for example, can distant scenes be made to look like they’re in 3-D (long distances dilute the effect) without artificially separating the camera pickups of the two eye views, which would make people seem tiny, as though viewed by a giant?

As the existence of the SMPTE PDA webcast shows, effort is being devoted to production issues. And, as the appearance of a glasses-free 3-D mobile-phone display at the exhibit of Korea’s Electronics and Telecommunications Research Institute (ETRI) at the 2009 National Association of Broadcasters (NAB) convention shows, effort is also being applied to the technical issues.

The third category, however, is psychophysical issues–how viewers respond psychologically to the physical stimuli of 3-D imagery. Part I of this series covered one psychophysical issue, the convergence-accommodation disparity (viewers’ eyes point to one distance while their eyes’ lenses might focus on another). That disparity can introduce eye strain and fatigue–perhaps even nausea–but, in the same way that experienced sailors can get over the perceptual disparity that causes seasickness, 3-D viewers who become sufficiently accustomed to stereoscopic imagery might be able to watch without discomfort.

The infinity-interpupillary problem is different. When looking at something infinitely distant, eyes point straight ahead, creating parallel views separated by the same distance as the centers of their pupils — nominally a little more than two-and-a-half inches in a human adult. If a screen were to be placed in front of those eyes–at any distance away–the stereoscopic left-eye and right-eye images on that screen would have to be that same interpupillary distance apart.

In 3-D, “infinity” can actually be pretty close. When looking at something at a distance of 120 feet, our eyes each “toe-in” from looking straight ahead by less than five hundredths of one degree each. At 30 feet, it’s just two tenths of a degree. At even just six feet, there’s less than one degree of angular change per eye.

That’s not too much of an issue for 3-D in a movie theater. The left- and right-eye images of a distant object can be placed 2.5 inches apart. Unfortunately, if that’s done for a 30-foot-wide screen, then they’ll be five inches apart when the same movie is shown on a 60-foot-wide screen, requiring unnatural eye divergence.

On a 15-foot screen, everything would appear to be too close. On a home TV, the same object would seem really too close. That’s why 3-D TV might not be able to “repurpose” 3-D movies directly. As for yet smaller displays, is the screen on a mobile phone even 2.5 inches wide?

Perhaps that’s one reason why 3-D TV has yet to take off. The first 3-D TV broadcast was in 1928, and by 1953 Business Week ran the headline “3-D Invades TV.” Stereoscopic TV is hardly new. The idea that 3-D needs to recreate the depth cues of the real world, however, is arguable. Is 3-D, like sound, color, and increased detail, the next step towards reproducing reality? Or might it be more like film music?

No one would argue that music adds to the reality of dramatic or comedic programming. We don’t go through life with a band of personal musicians providing a background to our emotional states. But there’s also little doubt that music can enhance that programming. The same Alfred Hitchcock who tried 3-D in Dial M for Murder also performed an experiment in Psycho. To save money, the director shot the movie with the crew that worked on his TV series. But, according to Steve Vertlieb, in Midnight Marquee magazine in 2002, “Hitchcock himself had begun to have serious misgivings about the picture. It seemed somehow flat and lifeless, and he gave serious thought for a time to cutting the film down to an hour and releasing it as a part of his long running television series.”

What changed his mind was Bernard Hermann’s music score. It converted what might have been a mere TV episode into a movie classic, the American Film Institute’s number-one thriller of all time.

Could 3-D be similar to movie music? The stereoscopic scene shown on the mobile phone at the ETRI exhibit at NAB 2009 was hardly realistic. The trees in a forest glade seemed just inches apart. At the same time, the view was captivating. Imagine! There was a 3-D picture on a mobile phone!
Stereoscopic 3-D will do nothing to make the images on a mobile screen seem bigger, more detailed, or more realistic. But, if it entices users to pay for what they otherwise wouldn’t (or pay more for what they otherwise would), who cares?

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