Eyeballing 3D errors


Standard-issue human eyeballs are very adaptive and clever. Of course it’s the massively powerful image processing in the visual cortex of the brain that really allows us to resolve 3D images. Stereographers have been very practised over the years in achieving good camera set-up with only simple tools. The most common test uses a picture monitor showing left eye image subtracted from the right. Depth disparities show up as blackish or whitish edges on any vertical edge features creating parallaxes. This display also shows vertical disparities and any rotation (roll) problems. However, to measure actual values of anything, a plastic ruler might be needed. (This is frequently only too true.) Slightly better, some of the specialised monitors have a grid or an offset control allowing visual estimate of disparity values. With a complicated scene, there will be many different points in the image to consider. It is then very difficult when objects and people are continually moving around. That is one reason why stereoscopic analysers are really needed.
Where a production is destined for the cinema, the large screen sizes available predicate for large disparity ranges. So the depth budget will allow larger pixel or screen percentages than those smaller ranges essential for TV. Curiously, this means cinema is actually easier to eyeball set-up than TV. In any case, cinema folk are not going to be very happy to accept 3D with basic errors that could have been avoided by proper measurement and quality control. Using a 3D display monitor is not an option for measurement. The eyeballs of an experienced operator will tolerate a wider range of depth than real audiences.
A number of on-set and post-production tools are now available which directly measure depth budgets as actually being imaged by the cameras. Some of these only show numerical results or a confusion of tagging feature points overlaid on a monitor. You can use a depth map to ‘eyeball’ the depth accurately in a whole scene. The stereoscopic analyser translates disparity values found by comparing left with right eye images into depth value. The depth values across the analysed picture are then translated into colour values according to a look-up table. Rather like a contour map of the countryside, this reveals the topography of the 3D scene. The disparity extremes that exceed the preset depth budget limits can be portrayed in warning colours. Excess negative (in front of the screen) is flagged in mauve. Other discrete colours show the intermediate values in use. The Cel-scope3D analyser has this mode among its facilities. It offers a number of different LUT colour schemes which can be selected. The one illustrated has white corresponding tozero parallax or no depth. With a colour depth map, you can instantly see where and when you are off budget.
Robin Palmer is Managing Director of Cel-Soft and is currently involved with software solutions for 3D & TV quality control and measurement technology.

Tags: 3d | iss050 | 3d errors | cel-soft | stereographer | cel-scope3d | N/A
Contributing Author N/A

Read this article in the tv-bay digital magazine
Article Copyright tv-bay limited. All trademarks recognised.
Reproduction of the content strictly prohibited without written consent.

Related Interviews
  • 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
NEP Student Day
KitPlus The world of broadcasting is in constant flux, with undefined boundaries between broadcast, TV, film and interactive media. With a changing consumer demographic now a key influence on the industry, many companies no longer specialise in a single medium, but have had to become adaptable to deliver multiple services through a combination of media.
Tags: iss134 | students | tvfutures | NEP | KitPlus
Contributing Author KitPlus Click to read or download PDF
Keeping it remotely real
Reuben Such Everyone wants to do more with less. Always have, although it could be argued that doing more with more is something to aspire to, not many have that luxury. So let’s stick with the prevailing winds of doing more with less, and not just doing more, but doing it remotely, particularly in terms of production. Remote production, in particular, is getting a lot of attention in the field these days, but not so much in terms of the remote operation of fixed studios.
Tags: iss134 | remote control | IPE | IDS | Reuben Such
Contributing Author Reuben Such Click to read or download PDF
Protecting the continuity of transmission
Lorna Garrett Your viewers love you. You consistently bring them their preferred channels 24/7. They’ve come to rely on you for their viewing pleasure. They never miss cheering on their beloved sports teams. They’re the envy of their friends as they watch live concerts of their favourite bands. They gather the family around and catch up on their must-see shows. They don’t have a bad word to say about you.
Tags: iss134 | garland | gpl | streaming | artel | disaster recovery | Lorna Garrett
Contributing Author Lorna Garrett Click to read or download PDF
The Wireless Way to 4k
JP Delport DTC’s AEON group of products have been specifically designed for the 4K market. We encode with the more efficient HEVC algorithm, which means we are taking a 12G signal and compressing it to a bitrate that can be managed over an RF link. So what makes this a leading idea in the 4K revolution?
Tags: iss134 | wireless | 4k | transmission | JP Delport
Contributing Author JP Delport Click to read or download PDF
What content providers need to know about OTT
Hiren Hindocha As OTT (Over-The-Top) technology has gotten more mature and established robust standards over the years, the concept of OTT monitoring is gaining popularity. With customer expectations soaring, it’s vital for OTT providers to deliver superior quality content. To deliver Quality of Experience (QoE) on par with linear TV broadcast, the entire system, starting from ingest to multi-bitrate encoding to delivery to CDN must be monitored continuously.
Tags: iss134 | ott monitoring | qos | logging | compliance | dash | atsc | cloud | Hiren Hindocha
Contributing Author Hiren Hindocha Click to read or download PDF