3-D: Unfortunately, It's NOT Just Technology and Technique

Despite the recent clamor for 3-D movies & television, there are physiological and psychological hurdles.

Here is a headline that appeared in Business Week magazine: "3-D Invades TV."  The issue in which it appeared was dated May 3, 1953, and it was by no means the first time 3-D was considered for television; decades earlier, the first 3-D TV demo took place in Britain.

 

Today, more than half a century after the Business Week headline, there are many reasons to believe that 3-D is closer than ever to taking over the moving-image media.  New tiny high-definition cameras can be placed as close together as a pair of eyes.  Advanced post-production software can correct differences between the two signals.  Digital distribution technologies allow 3-D to be transmitted within single channels.  Cinema and home display technologies are more "stereo-friendly" than ever before.  And the 3-D Hannah Montana movie had amazingly high opening-weekend box-office gross revenues.

 

On the other hand, a later, non-stereoscopic Hannah Montana movie reportedly had an even-higher opening-weekend gross.  And more-serious 3-D issues relate to the physiology and psychology of human vision.  One is called the "infinity-interpupillary" problem; another is the "accommodation-vergence" problem.

 

The infinity-interpupillary problem relates to the way we see distant objects or scenes, with our eyes pointing straight ahead.  To match that, a 3-D display should have those objects at the same spacing -- roughly 2.5 inches apart.  That's easy to achieve on almost any screen, from a TV set to a movie palace.  Unfortunately, points that are 2.5 inches apart on a TV screen will be much farther apart on a movie screen, demanding our eyes to try to diverge, an unnatural condition.  Conversely, points that are 2.5 inches apart on a movie screen will be much closer on a TV screen, giving the impression that distant objects are much closer, as though the viewer had the eyes of an office-building-sized giant.  And, on a mobile-phone screen, the 2.5-inch spacing could be simply impossible.

 

The accommodation-vergence problem relates to human-visual feedback mechanisms associated with lens focus in the eyes (accommodation) and the angle at which they point (vergence or convergence).  In the real world, the two are locked together.  In most forms of 3-D (holography is an exception), the vergence might be in front of the screen or behind it, whereas the accommodation is always at the screen distance.  Professor Martin Banks of the University of California in Berkeley presented evidence to the 2009 Digital Cinema Summit in April that the accommodation-vergence problem can cause physical discomfort.

 

Neither problem is necessarily insurmountable.  One hope is the fact that human perception can be trained.  When the Lumiere brothers showed a black-&-white, silent movie of a train in 1895, a contemporary account suggested that at least one audience member feared there was a locomotive in the room.  Long before high-fidelity, a reporter for the Pittsburgh Post said he was unable to tell the difference between an Edison phonograph recording of an opera singer and the real thing.

 

Today we might find those reports laughable.  If so, it's because we have been trained to recognize visual and aural recordings.  Similarly, although a first mountain hike can result in sore muscles, we can train ourselves to hike without the soreness.

 

Perhaps we can be trained to deal with the infinity-interpupillary and accommodation-vergence problems, too.  But the long-term success of 3-D as more than a novel gimmick, alas, will require more than shooting, transmission, and stereoscopic-display developments.

This author consults with leading institutions through GLG