It began with a presentation by CableLabs vp of consumer video technology David Broberg of almost every possible method for delivering 3D via cable, most of which involve a reduction of horizontal resolution (side-by-side images), vertical resolution (over-under), temporal resolution (alternating frames) or some combination.  There are mechanisms for delivering 3D in HD (Walt Husak, Dolby’s director of image technologies, later described some), but they’re not available in first-generation implementations using existing set-top boxes (STBs).

NDS system architect Kevin Murray offered other reasons why those STBs might need to be changed, including making sure that such graphics as captions and program guides are placed in 3D space in front of any picture content they occlude.  Current STBs not only don’t take depth into account but would also place a single caption across the width of a side-by-side 3D image pair, making it impossible to read even with one eye closed.

What about future non-glasses multiview systems?  As a participant on the panel, I pointed out that the number of views divides the spatial resolution.  That led an NHK demo shot with an ultra-high-definition (”8K”) camera to appear to have lower resolution than even a YouTube clip.

There’s more coverage of the session in yesterday’s Multichannel News here: http://www.multichannel.com/article/452530-Cable_Show_2010_3DTV_Work_Left_To_Be_Done.php

My paper from the proceedings can be found here: Mark Schubin’s paper from the 2010 Cable Connection Spring Technical Forum Proceedings and is copyright 2010 by the National Cable & Telecommunications Association

As people age, unfortunately, they become less able to focus at different distances, a normally occurring condition called “presbyopia.”  And that means that a stereographer with presbyopia can’t properly judge vergence-accommodation conflict.

There’s more here: http://www.prlog.org/10611247-woods-hole-imaging-systems-group-to-launch-3d-hd-unit-at-2010-nab.html

That concept — and a way to marry the two — is spelled out in “Broadcast Spectrum or Broadband Spectrum? We Want Both,” by Eliot Van Buskirk in Wired: http://www.wired.com/epicenter/2010/03/fcc-mobile-tv/

Thanks to Doug Lung for pointing out the story in his RF Shorts in TV Technology: http://tvtechnology.com/article/97760

It begins, “If the test footage shot recently at the Augusta National Golf Club is an authentic gauge, the Masters in 3-D will look terrific.”  And, until the very end of the article, it seemed only to get better still.

At the very end, however, Sandomir acknowledged some “flaws,” one that “blurred” the picture, another that was “visually jarring,” and a third that “was dizzying.”  The review ends with a quote:

“‘We’re figuring out what works and what doesn’t,’ said Mark Francisco, a Comcast Fellow working on 3-D.”

Here’s the first sentence of the editorial writer’s official biography: “Gary Shapiro is president and CEO of the Consumer Electronics Association (CEA), the U.S. trade association representing some 2,000 consumer electronics companies and owning and producing the world’s largest tradeshow for consumer technology, the International CES.”  As such, he is, among other things, the cheerleader-in-chief for the organizations manufacturing 3DTVs.

Yet his editorial in the current (March/April) issue of Vision magazine calls for some braking of the 3DTV steamroller.  ”We must agree on standards so consumers can invest in glasses.  We must understand that those with eye issues, monovision or susceptibility to motion sickness may not appreciate 3D.  We need to qualify consumers and set their expectations to avoid 3DTV returns.  We need to understand the benefits and any potential harm from 3D viewing.”

There’s lots more here: http://www.nxtbook.com/nxtbooks/cea/vision0310/index.php?startid=2#

It’s well worth reading.

One note: It’s not necessarily a bad thing to be unable to see 3D when the axis of your eyes is vertical.

The presentation offered a good overview of 3D production in general and then concentrated on the camera.  Small image sensors were chosen to allow a side-by-side configuration, even though that led to reduced sensitivity (the 3D camcorder was the only one in the demo room to require additional lighting instruments).  The lens motors are controlled together (Fujinon had a demo in the same room for a common calibrator and controller for paired 3D lenses), and the same system used for chromatic-aberration correction can be used to correct geometric distortion and differences between the left- and right-eye pickups.

So why isn’t the optical system finalized?  Panasonic wants this to be a 3D-training camcorder and, as such, as simple to use as a bicycle with training wheels.  Zoom range will be affected by convergence angle (and at the HPA Tech Retreat at least one participant expressed an opinion opposing convergence, because it effectively changes the frame shape at any fixed plane from the camera from two rectangles to two trapezoids, with opposite short and long sides for the two views, introducing an undesirable vertical-scale difference).

The presentation also covered the professional monitor, which, unlike consumer devices, uses crossed linear polarization.  One advantage of linear polarization is that it tends to offer less ghosting (especially in blues) than circular polarization, if the viewer’s eyes are as horizontal as the display.

The seeming disadvantage is that a viewer cannot put her or his head on someone else’s shoulder without getting severe ghosting.  But that same characteristic might be seen as an advantage for a professional monitor; when one’s eyes aren’t horizontal, one isn’t seeing 3D properly, regardless of ghosting.  The ghosts act as a self-corrective to head position.

There were many more 3D presentations and demonstrations at the HPA Tech Retreat, including TDVision on 3D to mobile devices (they had an encoding demo), Miranda on the proper z-axis positioning of graphics, and Dolby showing HD 3D on a giant screen in just about 7.5 Mbps.  There was the 1 Beyond Wrangler for portable 3D recording and review, Cobalt’s UDX 3D processor, Doremi’s 3D format converter, DVS’s system for 3D digital-cinema package (DCP) creation, including subtitles, Fraunhofer’s 3D DCP player (and immersive 3D-capture system), GIC’s 3DV quality-control (and subtitling) system, 3D-shooting tools from IFX, Imartis’s rapid-stereo-adjustment SwissRig, and JVC’s 3D upconverter-mixer-monitor system.

Oculus 3D showed a brand-new system for film-based 3D in movie theaters (Technicolor just announced another).  OmniTek offered 3D test patterns and a range of 3D displays (waveform, histogram, metadata, and picture-difference among them).  Quantel had their latest 4K 3D software.  Ross Video had a 3D character generator.  SpectSoft had a new 3D converter (as well as other 3D features).  THX had 3D signaling for home theaters.  T-VIPS had 3D-over-IP using JPEG2000.  And I might have missed some of the 3D demos.

There were also at least a dozen breakfast roundtables at which 3D was discussed — everything from the effect of blur on the perception of depth to the use of 2D equipment in 3D production.  What there didn’t seem to be was anything on the mysterious single-lens 3D camera shown by Sony at CEATEC.

The unofficial motto of the HPA Tech Retreat, however, is “someone will be there who knows the answer.”  Sure enough, at a networking opportunity, it was possible to get not only the lowdown on the single-lens Sony 3D camera but even an unpublished paper about it and the published research on which it’s based.

The subject of that research is “microstereopsis,” and it has been studied in many labs around the world.  At a breakfast roundtable at the HPA Tech Retreat, Professor Martin Banks of the University of California – Berkeley noted that the human visual sensitivity to disparity between the left- and right-eye views (stereopsis) is a full factor of magnitude greater than its sensitivity to detail resolution.

In an ideal 3D system, the cameras would shoot views matching the distance between the centers of a viewer’s pupils (pupillary distance, or PD), and the display would duplicate that.  But different viewers have different PDs, and screens come in a range of sizes.  To keep viewers from ever having to (unnaturally) diverge their eyes, the views, especially on TVs, are usually presented at considerably less than the viewer’s PD.  If the cameras had a greater separation, the result can be a sensation of looking at a doll house, with a shortened depth sensation.

So why not shoot with a reduced PD in the first place?  That’s the idea behind microstereopsis.  One paper about it is called “Kinder Gentler Stereo.”  Another is “Just Enough Reality.”

Digital Optical Television Systems used a single-lens 3D camera in the early 1970s.  Sony’s CEATEC camera — not yet intended as a product — is another.  It shoots at 240 frames per second for a different kind of sensation and uses ordinary zoom lenses, which cannot be mismatched because only one is used at a time.  Behind the lens, a mirrored optical system splits the two views and sends them to different paths, but the two eye views can actually be recombined and viewed comfortably as 2D.  Pictures from the camera were actually shown at last year’s Consumer Electronics Show.

There was lots more at the 2010 HPA Tech Retreat.  If I get a chance, I’ll provide some more in a future post.  Meanwhile, you can read up on it at the URLs I provided last time: http://schubincafe.com/blog/2010/03/2010-hpa-tech-retreat-what-gave-some-avatar-viewers-discomfort/

The first iPad has yet to be sold, but Broadcast Pix has already announced iPixPanel, an application that allows an iPad to control Slate production switchers.  There’s more here: http://www.broadcastpix.com/Press-Releases/-New-iPixPanel-Turns-Apple-iPad-into-Control-Panel-for-Broadcast-Pix-Systems.html

I’m going to start with something that has been bothering me about a subject I’ve covered here, the seeming need for 2D glasses for some viewers of 3D (see “2D (not 3D) Glasses” http://schubincafe.com/blog/2010/02/2d-not-3d-glasses/).  I could understand the issue for home TVs, where short viewing distances could cause a conflict between visual accommodation (eye focus, which is always on the screen) and vergence or convergence (the aiming of the eyes, which could be far behind the screen or in front of it).  But I had a hard time understanding why there have been so many complaints of 3D discomfort, worldwide, from people watching Avatar in movie theaters.

Avatar seems to have superb 3D, without wild, in-your-face effects.  And movie theaters have viewing distances that should minimize, if not altogether eliminate, vergence-accommodation conflict.  So what was making those viewers (only a minority) queasy?

One possible answer was provided at one of those networking opportunities at the HPA Tech Retreat.  An engineer noted that his wife became queasy at Avatar but had also become queasy at another, non-3D James Cameron movie, Titanic, when the floors and walls shifted and the views got vertiginous.  So maybe it was just people susceptible to queasiness when visual cues don’t match those of the vestibular system (the semi-circular canals of the inner ear), the same conflict that causes sea sickness.  And maybe the reports came out in association with Avatar just because of the magnitude of its 3D buzz.

Unfortunately, at another networking opportunity, a viewer who got queasy watching Avatar said she’d had no discomfort when watching Titanic or even more vertiginous movies.  So what had caused the issue for her?

One of the speakers at the 3D-in-the-Home supersession at the HPA Tech Retreat was Professor Martin Banks, who heads the Visual Space Perception Laboratory at the University of California – Berkeley.  That’s the lab that proved, perhaps for the first time, that there is a vergence-accommodation conflict (see “3DTV: Home and the Range” http://schubincafe.com/blog/2009/11/3dtv-home-and-the-range/).  But that explains discomfort primarily at close home-viewing distances, not in cinemas, especially if what’s being viewed is not in-your-face 3D.

Adam Wilt has provided comprehensive coverage of the HPA Tech Retreat on his ProVideo Coalition Camera Log http://provideocoalition.com/index.php/awilt/story/hpatr2010_1/.  Be sure to go to the other pages and other days of his coverage to get a good taste of the event.

If you scroll down on the first page, you’ll come to some of Banks’s diagrams.  Note that, as far as vergence-accommodation conflict is concerned, “Percival’s zone of comfort” covers most cinema-viewing conditions but not all home 3D conditions.  Scroll down a bit more, however, and you’ll see that 3D has a narrower acceptable viewing angle than 2D, at least for some purposes.  So maybe that’s what’s been causing some Avatar viewers discomfort.  Maybe they were seated outside the acceptable viewing angle.

I’ll get to more of the 2010 HPA Tech Retreat in future posts, but, in the meantime, in addition to Adam Wilt’s coverage, you might check these others:

http://www.hdtvexpert.com/?p=256
http://www.studiodaily.com/main/news/headlines/3D-TV-Mobile-and-More-at-2010-HPA-Tech-Retreat_11958.html
http://www.televisionbroadcast.com/article/94876
http://www.televisionbroadcast.com/article/94880
http://www.televisionbroadcast.com/article/94888
http://www.televisionbroadcast.com/article/94914
http://www.televisionbroadcast.com/article/94918
http://www.televisionbroadcast.com/blog/95048
http://www.mobilizedtv.com/behind-the-mobile-dtv-scenes
http://www.mobilizedtv.com/the-brewing-battle-over-spectrum
http://www.mobilizedtv.com/six-tips-for-a-digital-transformation
http://www.dtvusaforum.com/mobile-dtv/24411-who-has-mobile-dtv-rights.html
http://tech.ebu.ch/news/3d-tv-gains-momentum-in-the-us-18feb10
http://bradfortner.wordpress.com/2010/02/17/hollywood-post-alliance-tech-retreat-2010-a-preview-of-nab-2010/
http://bradfortner.wordpress.com/2010/02/18/atsc-audio-seminar-the-package/