Session 4: Keynote Speaker: Mark Schubin, Technology Consultant
What is 3D?
Jan 14, ITU-R SG6 defined 3 generations of 3D; first generation is plano- stereoscopic (with 4 sub-levels, 1 = anaglyph), second generation is multiview, and third generation is object-wave profile (holography), which is 15-20 yrs away. RabbitHole is delivering film-based holography (we have examples in the ETC Consumer 3D Experience Lab). It is limited to 1280 frames.
Less than full stereoscopic is enhanced chromostereopsis and pulfrich effect. Chromostereopsis works as long as you control the colors in the scene. View-shifting works by jiggling, and microstereopsis (Trioscopics) doesn’t cause vision problems but doesn’t work well either.
The term ‘3D graphics’ is used for both CGI and stereoscopic 3D, which can make conversations confusing.
POOT is plain old ordinary TV. If you close one eye, you might sense depth.
He reviewed the visual cues mentioned by Pete Lude in a previous talk. Papers by S. Nagata, 1991 and J. Cutting & P. Vishton, 1995 contain graphs illustrating the influence of the various cues.
Ames rooms confuse perspective vs. size cues. (Ames rooms are the distorted, optical-illusion rooms that make the same object appear huge in one corner and tiny in the other.) Five Ames rooms were used in Lord of the Rings to make Gandalf appear much taller than the Hobbits. If Lord of the Rings was shot in 3D, the effect would not work.
Why does 3D matter?
Things to consider when creating 3D:
– The placement of the convergence point when shooting
– Pupillary distance can be 40-80 mm for children
– Screen size
– Viewing distance (if your pupillary distance matches the negative parallax on the screen, the object will come out 3’ if you are 6’ away, and 25’ if you are 50’ away, which is less credible.)
The movie theatre is not the home. In a theatre, the audience is most likely entirely in the zone of comfort. At home, the zone of comfort is only a small portion of the available seating locations around the TV.
Conflict / Effect
– perspective-size / incorrect relative size
– occlusion – stereopsis / graphics difficult to view
– vergence-accommodation / possible discomfort
– stereovisual – vestibular / possible discomfort
– stereopsis – vergence / incorrect depth
– impairment, choice / might training help the muscular areas? We don’t know.
Why are so many TVs coming out with active shutter technology? Because polarization is hard to implement. With active shutter, you don’t have to do anything to the screen. You just add the emitter, so it ends up about the same price. This is good for the CE manufacturer, because they are not necessarily concerned about the cost of the glasses. Also, the battery life of the battery in the glasses is not their concern.
While people who are sensitive to 3D can watch polarized in 2D by putting the same lens in both eyes, isolating one image for both eyes in active shutter glasses may produce flicker.
BBC R&D White Paper 180, posted on the web, discusses how to synthesize 3D.
Steve Scklair said 3D requires fewer camera positions.” The same was said at the birth of HDTV. Audience expectations evolved, so expect the gradual adoption of faster cuts and shorter scenes.
Terms that are often used in marketing and press releases but rarely credible include: “the first”, “successful”, and “good enough.”
A paper by I. Howard & B. Rogers, 1996, discussed microstereopsis. Human perception of stereo is greater than human perception of luminance.
Digital Optical Technology Systems, The Netherlands, is a glasses-free display that uses a slit iris to induce color fringes that creates a 3D effect. The patents for this technology have expired. It works with one ordinary lens per camera position, as long as it is outfitted with a slit iris. This solution, which has a nearly zero interocular distance, has no ghosting, but it is incapable of a WOW effect. It is a ‘kinder gentler 3D.’
(See Gary Shapiro’s editorial on 3D in the current issue of Vision magazine.)
Q&A
What types of content are particularly suited for 3D? From a physiological standpoint, talking heads and children’s shows are well suited for 3D because of narrow depth range and comfort. Getting people to buy things, though, will take sports and movies.
How can you shoot the Grand Canyon in 3D? Make the camera spacing very large. Hyperstereo reduces the 3D at a distance and heightens it up close.
Do you want to make any points about Avatar? We need to interview everyone who had a problem viewing Avatar. That is the epitome of 3D, so we need to understand why those people had problems.
Why is this rebirth of 3D different? We have the digital technology, management of the convergence plains (keystoning), multiple camera sizes are available, and other factors, so from a technical perspective we are in a new place. I cannot speak to the market question of whether this is the future.