Why do poorly composed 3D stereoscopic images give headache and eye-strain problems


The brain is used to being able to “fuse” the two separate views of the world seen from each eye into a 3D perceived scene. However we have a closed-loop system and the eye muscles constantly pull convergence and focus depending on the region of interest. When presented with two separate image streams originating from the left and right camera systems of a 3D rig, the eye – brain coupling has to deal with potentially unusual errors, inconsistencies and paradoxes to try and fuse the images into one. If any one or more of the many possible camera misalignments is out, then for some people who view the 3D, their brain and eyes will struggle to pull-in the images and make sense of them – hence the problem.
Relative to each other, there are 5 axis camera alignments that must be set very accurately and held during shooting. This is why 3D rigs are (or should be) so solidly built, to ensure camera alignment can be set-up and rigidly maintained. There are the 3 relative rotations: pitch, roll and yaw. In 3D the yaw (Y axis) rotation is particularly important as it sets the convergence of the optical axes. Any vertical misalignment must be eliminated and needless to say, both cameras should be on the same focal plane.
The other axis is the interocular, the distance between the lenses and is more an artistic decision than a technically fixed point. There can be wide range of variation chosen, depending on the scene and the intended viewing conditions. Added to 5 critical camera axes, there are the variations and inconstancies between the lenses. Further more, there are many additional factors inherent in each camera to affect matching such as white balance, gamma and image stabilisation – which should be off.
In some opinions there is an attitude of assuming everything can be ‘fixed in post’. This may not always be possible such as with lens flare or lost genlock. It is certainly not optimum, not just because of the time and cost but because any fix to a stereo pair’s geometry must involve having to throw away part of the source images or compromise the dynamic range and resolution. For these reasons initial camera set-up, alignment and monitoring before and during shooting is critically more important in 3D than 2D. Its not just one extra dimension to make good 3D – it’s a dozen or more.

Tags: 3d stereoscopic | 3d diaries | cel-soft | white balance | gamma | 5 axis camera alignment | 3d | iss041 | N/A
Contributing Author N/A

Article Copyright tv-bay limited. All trademarks recognised.
Reproduction of the content strictly prohibited without written consent.

Related Interviews
  • 3D Storm show the new NDI to HDMI decoder at NAB 2019

    3D Storm show the new NDI to HDMI decoder at NAB 2019

  • 3D Storm presents LiveXpert and NewTek products at IBC 2018

    3D Storm presents LiveXpert and NewTek products at IBC 2018

  • 3D Storm discuss IP and NDI for Live Media Server and Live CG Broadcast at NAB 2018

    3D Storm discuss IP and NDI for Live Media Server and Live CG Broadcast at NAB 2018

  • LiveCG Broadcast and LiveMedia Server from 3D Storm at BVE 2018

    LiveCG Broadcast and LiveMedia Server from 3D Storm at BVE 2018

  • NDI and Newtek Products from 3D Storm at IBC 2017

    NDI and Newtek Products from 3D Storm at IBC 2017

  • LiveMedia Server and Live Xpert from 3D Storm at NAB 2017

    LiveMedia Server and Live Xpert from 3D Storm at NAB 2017

  • 3D Storm with LiveXpert at BVE 2017

    3D Storm with LiveXpert at BVE 2017

  • 3D Storm at IBC 2016

    3D Storm at IBC 2016

  • 3D Storm at BVE 2016

    3D Storm at BVE 2016

  • 3D Storm at IBC 2015

    3D Storm at IBC 2015

  • Brainstorm Multimedia: Aston3D at NAB 2013

    Brainstorm Multimedia: Aston3D at NAB 2013

  • Brainstorm Multimedia at IBC 2015

    Brainstorm Multimedia at IBC 2015

  • BRAINSTORM VIRTUAL SETS at NAB 2015

    BRAINSTORM VIRTUAL SETS at NAB 2015

  • Brainstorm Multimedia at BVE 2015

    Brainstorm Multimedia at BVE 2015

  • Brainstorm on BroadcastShow LIVE at IBC 2013

    Brainstorm on BroadcastShow LIVE at IBC 2013

  • Brainstorm with Aston demonstration at IBC 2013

    Brainstorm with Aston demonstration at IBC 2013

  • Brainstorm at IBC 2013

    Brainstorm at IBC 2013

  • Featured Clip: Geoff Boyle comments on NAB 2012

    Featured Clip: Geoff Boyle comments on NAB 2012

  • Brainstorm at NAB 2012

    Brainstorm at NAB 2012

  • VIZRT at BVE 2012

    VIZRT at BVE 2012

  • Newtek at BVE 2012

    Newtek at BVE 2012

  • Sony at ProVideo2011

    Sony at ProVideo2011

  • Sisvel Technology at IBC2011

    Sisvel Technology at IBC2011

  • Sensio at IBC2011

    Sensio at IBC2011

  • Panasonic at IBC2011

    Panasonic at IBC2011

  • Doremi at IBC2011

    Doremi at IBC2011

  • Matrox at IBC2011

    Matrox at IBC2011

  • Blackmagic at IBC2011

    Blackmagic at IBC2011

  • SGO at IBC2011

    SGO at IBC2011

  • Marshall Electronics at IBC2011

    Marshall Electronics at IBC2011


Related Shows
  • Show 20 - July 17th 2013

    Show 20 - July 17th 2013


Articles
How the Womens World Cup was Boosted by Broadcast
John Griffiths As we write this article, England’s Lionesses have just beaten Norway 3-0 and are smashing viewing figure records, with 6.9 million viewers tuning in to watch them play Cameroon on BBC One. Rewind to the previous World Cup in 2015, and England’s group and early stage knockout games tempted up to 2.5 million viewers for each match. It’s safe to say that women’s football is finally having its moment; what was perhaps once considered a niche sport is finally gaining momentum in the mainstream space with broadcasters giving it the attention it deserves.
Tags: iss138 | wwc | world cup | spicymango | diversity | John Griffiths
Contributing Author John Griffiths Click to read or download PDF
Industry Ready Broadcasting Students
KitPlus Cardiff Metropolitan University traces its roots back to 1865, when they opened their first school in an old library. Now Cardiff Met is a global, practice-focused and professionally oriented institution, committed to ensure every student fulfills their potential to make outstanding contributions in their future industries.
Tags: iss138 | newtek | live production | cardiff metropolitain | sports broadcasting | tricaster | cardiff devils | KitPlus
Contributing Author KitPlus Click to read or download PDF
How LiveU Has Changed The Way We Work At ITV Daytime
Tim Guilder As my job title suggests, I’m responsible for planning and executing technology projects across ITV’s Daytime, including outside broadcasts, which are central to what we do. We broadcast live for more than six hours every weekday with four shows: Good Morning Britain, This Morning, Lorraine and Loose Women. With a history as one of the main UK terrestrial broadcasters – of course, we have also evolved alongside the industry in terms of viewing options – we have high standards. We constantly generate new ideas to keep audiences engaged and we also need to be responsive to the latest breaking news.
Tags: iss138 | liveu | itv | daytime | cobham | explorer 8100 | satellite | lu600 hevc | ka-band | lu300 | garland | Tim Guilder
Contributing Author Tim Guilder Click to read or download PDF
The Evolution of Audio Monitoring
Stephen Brownsill Every user, production, environment, operation and application is different, meaning that universal tools simply cannot provide the versatility required by today’s customers. Audio monitoring continues to evolve as productions advance, with the need for multi-channel monitoring, configurable metering as well as the ability to adhere to the latest loudness guidelines remaining at the top of the must-have list.
Tags: iss138 | tsl products | st-2110 | lip synce | ip | ptp stauts | amwa | nmos | Stephen Brownsill
Contributing Author Stephen Brownsill Click to read or download PDF
TVFutures. No More Comfort Zone - Get a Placement
Michelle Brown I have often heard that any chance of getting work in the television industry is based quite heavily on who you know, and whilst that might indeed be true, I’ve also come to the realisation that it may also depends on what opportunities you seize and how far out of your comfort zone you might be prepared to push yourself.
Tags: iss138 | portsmouth uni | creative careers | placement | Michelle Brown
Contributing Author Michelle Brown Click to read or download PDF