[opendtv] Re: Researchers say eye strain a concern as 3-D TVs debut

  • From: Mark Schubin <tvmark@xxxxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Thu, 25 Feb 2010 19:39:27 -0500

The unnamed event was last week's HPA Tech Retreat in Rancho Mirage, with 453 registered participants. Banks spoke at the 3D-in-the-Home supersession on Tuesday and then had a one-hour breakfast roundtable on 3D and human vision the next morning. I agree that I'd love to listen to him for a day -- or maybe a week or a month.

His discussion of the vergence-accommodation conflict has appeared before. He's actually run tests in his lab and described the experimental apparatus and methodology. He noted how Percival's Zone of Comfort is reduced as viewing distances drop, as they do in home TV as compared to 3D cinema. But he also offered what seemed to me a clue about why some people (but only a minority) have complained of discomfort even when watching the excellent 3D of "Avatar" in a cinema. Banks showed experimental results that indicate a much more narrow acceptable viewing angle for 3D as opposed to 2D; maybe those complaining of problems in "Avatar" were outside the acceptable viewing angle.

Banks covered LOTS more stuff, including the role of blur. He also had some good things to say about certain 3D technologies like shutter glasses, which, he said, provide very good flicker performance.

By the way, there has been lots of coverage of the HPA Tech Retreat. Here's some of it:
(follow the side links to additional pages and days)

I imagine more will be appearing soon.


On 2/25/2010 6:43 PM, Manfredi, Albert E wrote:
Researchers say eye strain a concern as 3-D TVs debut
Vendor groups discuss but yet to act on sensitive issue

Rick Merritt
(02/25/2010 4:18 PM EST)
URL: http://www.eetimes.com/showArticle.jhtml?articleID=223100762

SAN JOSE, Calif. - Experts in human perception are expressing concerns stereo 
3-D TVs now hitting the market could cause eye strain and related health 
problems. Industry groups are actively discussing the topic, but in their rush 
to get systems out the door vendors have yet to fund any major studies of the 

Stereo 3-D movies and television could generate as many as seven different 
perceptual problems, said Martin Banks, a professor of optometry and vision 
science at the University of California at Berkeley. He gave a talk earlier 
this month for a broad group of consumer and Hollywood technologists about some 
of his biggest concerns, and was invited to come back to give a day-long course.

"They seem concerned about it, and my impression is they want to address this," Banks 
said of multiple contacts he has had with the industry. "They know they will kill the business 
if they make an unpleasant experience for people, [but] the question is what they will 
implement," he added.

"I think there are real things to be concerned about with the use of stereo displays 
becoming very widespread, especially if younger children are exposed to them 
routinely," added Simon Watt, a lecturer in the school of psychology at Bangor 
University in Wales who, like Banks, has been conducting studies on eye movements and 
stereo 3-D displays.

One of the main issues the researchers are studying is the so-called 
convergence-accommodation conflict. People watching stereo 3-D content have to 
adjust what they see at one point on a flat screen to information in the 
content that tells them that object is at another point in 3-D space. Such 
adjustments are not needed in the real world, so the human brain is not wired 
to handle them smoothly.

"We were the first to show that causes a variety of symptoms people can find 
unpleasant" such as headache and fatigue, said Banks.

Recent 3-D movies such as "Avatar" did a good job of minimize the effect, Banks 
said. But "as you decrease the distance [to the display] the problems created by this 
conflict accelerate and it's non-linear so they accelerate quickly.

"Things you could get away with in movies, you can't in a video game where a kid is 
close to the screen, so I am more troubled about stereo 3-D TVs than movies," he 

Both Banks and Watt are working on one possible solution. In separate efforts 
they are developing so-called multi-focal-plane displays that could reduce eye 

So far 3-D TV consortia in the U.S., Japan and Korea have discussed the issue 
in their meetings, but not taken any concrete actions.

"It's still in the discussion phase--we need someone to take the bull by the horns 
and create teams and structure and so forth," said Chris Chinnock senior analyst at 
market watcher Insight Media and a member of the 3D@Home Consortium.

"First, we need to characterize all the factors that can cause eye strain, then find 
ways to measure the levels of the effects and ultimately develop tools and rating systems 
for the content," said Chinnock, rolling out one scenario the groups have considered.

It's a sensitive issue for the vendor groups. "There's the danger of a panic about 3-D making 
you sick, and we've got to be careful about not starting that sort of stampede," Chinnock 
said. "The key to that is education and understanding what's real and what's not," he 

Taking a small step forward, Panasonic recently contributed an undisclosed amount to the 
Entertainment Technology Center (ETC) at the University of Southern California to fund 
the first step toward a broad study. "Our goal is to get scientifically and 
statistically valid data on the impact of viewing stereoscopic 3-D content among the 
general population," said Phil Lelyveld, a program manager at the ETC.

The Panasonic money will fund two pilot studies to establish the design 
criteria for two large population studies that still lack funding. Essentially 
the group aims to provide eye tests to a few theaters full of consumers before 
and after watching 3-D movies.

"There is no real data today, it's all anecdotal," said Lelyveld.

In a marketing survey of 1,914 adults conducted in December by the ETC and the 
Consumer Electronics Association, 18 percent of the group expected they might 
have eye strain or headaches from seeing a stereo 3-D movie. Only 12 percent 
said they had the symptoms after watching one.

Many of the issues are in the content-not the TVs--and may not rear their head 
for another year or two, said Chinnock.

"I am fairly confident in the first year or two we will have pretty good content because 
people are on to this," Chinnock said. "I am more concerned about what happens a few 
years out when amateurs put out a lot of stereo 3-D content.

"If someone tries to put a movie created for a theater screen on to a 46-inch TV you 
could blow your eyeballs out trying to focus on objects that are supposed to be behind 
you," he quipped.

Some of the new TVs will use algorithms to automatically turn 2-D content into 
stereo 3-D. Banks said he has not studied the 2D-to-3D techniques.

Those techniques typically create a sensation of depth behind the screen, not 
in front of it, said Chinnock and others. Thus they may create visible 
artifacts users may find crude but not contribute as dramatically to the 
convergence-accommodation conflict as effects that create depth in front of the 

Meanwhile the latest crop of 3-D TVs are hitting retail shelves at prices lower 
than some expected.

Sears announced Monday (Feb. 22) it has new stereo 3-D capable TVs from Samsung 
at prices as low as $2,500. Vizio, now the largest vendor of LCD-TVs in the 
U.S., announced models costing as little as $2,000.

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