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Re: live action for fulldome

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  • Ed Lantz
    ... True. One problem with this approach is that the brightest projectors available are challenged to achieve the 2-3 foot-lamberts of brightness that
    Message 1 of 20 , Oct 10, 2006
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      Don Davis writes:

      >If projector brightness increases dramatically the brightness of the
      >dome can be lowered. A massively brilliant projection on a nearly
      >black dome would be the ideal for delivering wide contrast.

      True. One problem with this approach is that the brightest projectors
      available are challenged to achieve the 2-3 foot-lamberts of brightness
      that large-format film deserves. Throwing away 90% of the available
      light is not a good situation. I also think there may be problems with
      very dark domes achieving neutral density across all colors. But, as
      you point out, a darker dome is currently the only way to improve
      dome-limited contrast.

      >I recall speculation 30 years ago about covering a dome with
      >honeycomb shaped partitions perhaps 1 cm across and high to reduce
      >cross-dome scatter, although the illuminated surfaces would still face
      >each other on opposite sides.

      >A 'scotchlite' like surface, silvery with strong backscatter
      >properties, would deliver a bright image for those seated near the
      >central projector, although the 'cone' of scattering may be something
      >that can be modified for given requirements. Such surfaces are
      >delicate and expensive.

      These approaches could work for a fisheye projector, but are not
      compatible with multiprojector configurations since image brightness
      in the blends is a function of both the angle of incidence and viewer
      angle. So the blends would only work for one viewer position.
      And, as you point out, light from the bottom of the dome will still
      reflect across the theater onto the opposite side of the screen unless
      there is an asymmetric reflectance curve that varies with elevation.

      >It is possible that tilted dome 'unidirectional' configurations are
      >better suited for these ideas, but restricted seating areas may be
      >implied by these methods. So long as we are talking about projections
      >on the inner surfaces of opaque domes I suspect the projector/dome
      >brightness will be the most fruitful forseeable progress in that area.

      Agreed. The problem can be addressed with a specially engineered
      dome screen surface, but that is still an R&D project.

      Ed
      ed@...
    • Erik Roberts
      I am curious to ask learned Planetarians, like Ed and Don and David et al, whether they think OLED domeskins will arrive to save the day in terms of black
      Message 2 of 20 , Oct 10, 2006
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        I am curious to ask learned Planetarians, like Ed and Don and David et
        al, whether they think OLED "domeskins" will arrive to save the day in
        terms of black levels?

        I guess it will also eliminate the projector(s)?

        Just trying to keep up with the Future.

        Thanks in anticipation...


        cameraderie
      • Ryan Wyatt
        It seems this is *the* topic for people who cannot post. Posted for Ka Chun Yu: === Hi Tim, ... Do you mean Raoul Grimoin-Sanson s Cinéorama , supposedly
        Message 3 of 20 , Oct 10, 2006
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          It seems this is *the* topic for people who cannot post.

          Posted for Ka Chun Yu:

          ===

          Hi Tim,

          > Well, there were several attempts in history to produce fulldome
          > "movies": Starting 1900 at the World Fair in Paris...

          Do you mean Raoul Grimoin-Sanson's "Cinéorama", supposedly footage
          from 10 interlocked 70 mm cameras arranged in a circle and mounted
          under a balloon, which lifted off from various European cities? The
          take-offs (and "landings" which was just the film running backwards)
          were said to have been shown in a giant 360 degree cylindrical room.
          Emmanuelle Toulet writes about the faux terrain of the viewing
          platform which included a fake balloon gondola, tackles, guide-ropes,
          ballast, etc., in her article "Le Cinéma a L'Exposition Universelle
          de 1900." The theater was shut down by the police after only four
          screenings because of the fire hazard from the projectors.

          However Vanessa Schwartz points out in her book, _Spectacular
          Realities: Early Mass Culture in Fin-de-Siècle Paris_ that Cinéorama
          never worked. (Toulet mentions that she was never able to find any
          public records or press supporting Grimoin-Sanson's story.) Schwartz
          cites Meusy, "L'énigme du cinéorama de l'exposition universelle de
          1900", _Archives_, no. 3, Jan 1991, which is difficult to find in the
          US. Does anyone have access to that issue of the journal?

          > Nowadays allsky.de and Hamburg Planetarium are developing several
          > camera systems for use in planetaria. Keep in mind that the viewing
          > angle is important for that. Tom Kwasnitschka was giving some good
          > hints on that earlier on the list.

          > Right now Hamburg Planetarium is working on adding some fulldome
          > movie content (10min) to our "Future is wild"-version; This time
          > timelapse will show the daily changes on our planet: rushing people/
          > cars, weather, tides, ...

          > For 2008 we?re working on a project about the Easter Island where
          > fulldome content will play a major role. It will combine the
          > traditional planetarium story telling with fulldome to provide more
          > touching and immersive emotions.

          > Many of our music shows use fulldome, like AERO (produced by
          > Starlight Productions) or Deep Space Night 2... and we?re looking
          > forward to use more and more reallife content ... there?s nothing
          > like reality.

          I would certainly welcome more information about your filmed content
          for your fulldome shows once they become available. You may know
          that I have emailed with Tom Kwasnitschka about this, so perhaps we
          can continue this conversation offline.


          -kachun

          +** Dr. Ka Chun Yu **+
          +** Curator of Space Science **+
          +** Denver Museum of Nature & Science **+
          +** 2001 Colorado, Denver, CO 80205-5798 **+
          +** kcyu@... 303-370-6394 **+
        • Mark C. Petersen
          Yes, contrast can be a problem. But besides the dome scatter and projector issues, consider the source. As I m sure the allsky.de guys can attest, anyone who
          Message 4 of 20 , Oct 10, 2006
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            Yes, contrast can be a problem. But besides the dome scatter and
            projector issues, consider the source.

            As I'm sure the allsky.de guys can attest, anyone who has shot
            fisheye all-skies knows you have a huge range of dark-to-light to
            deal with. Most skies are incredibly bright compared to the
            landscape around the horizons. If you set the exposure for the sky,
            the land is too dark; compensate the other way and your sky washes
            out toward white. And of course there are the inherent lens flares
            from the sun. It's nigh-impossible to capture a single all-around
            well-exposed frame.

            I bracket still exposures from way under to way over, twice -- once
            with my hand occulting the sun, once without. Then in Photoshop, I
            make composites, selectively choosing the properly exposed
            areas. The end result is an artifice, but looks good.

            But that's for stills. Trying to do that in real-time, in video...
            ummm, remains an exercise for the student.

            >> Mark


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          • Ed Lantz
            Hey Cameraderie - thanks for your cogent posts on this list! Wish I had time to respond to all the great fulldome posts that have been flying around... You
            Message 5 of 20 , Oct 10, 2006
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              Hey Cameraderie - thanks for your cogent posts on this list! Wish I had
              time to respond to all the great fulldome posts that have been flying
              around...

              You wrote:

              <<I am curious to ask learned Planetarians, like Ed and Don and David et
              al, whether they think OLED "domeskins" will arrive to save the day in
              terms of black levels? I guess it will also eliminate the
              projector(s)?>>

              This will eventually happen and, yes, it will solve problems with
              contrast, brightness, etc. (and create some new problems at the same
              time, no doubt). Although OLED may not be the first contender... Right
              now cost is the barrier. You don't see any flatscreen movie theaters
              using LED screens for this reason.

              E
            • Raymond Worthy
              Hello everyone, I have just been following the progress of the discussion and the contributions of Don Davis and Ed Lantz about the possible advantages of a
              Message 6 of 20 , Oct 10, 2006
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                Hello everyone,

                I have just been following the progress of the discussion and the contributions of Don Davis and Ed Lantz about the possible advantages of a near black screen.

                This is an amazing co-incidence. I have one.

                My set up is that I do all my marketing and ordering etc. from my home which is in Hartlepool. The factory where the domes are cut out and welded is located some forty miles away in a country town called Thirsk.

                It is a long time now since I made a dome with a white screen. all my current domes have grey screens to accommodate the digital projections which are now all the rage.

                The domes' outer polyester skins are usually black . There has been a series of these domes and the supply and delivery system has worked quite smoothly.

                Two weeks ago, I took a delivery of what I thought was enough of the usual fabric to make the next order. It came in two long boxes which I did not open and I delivered them to the factory on my next visit.

                A week later, I returned to the factory to examine my latest dome , only to find that they had made a chocolate tea-pot. The colours had been reversed. The outside was grey and the screen was black.

                The proud team stood around with expectant smiles on their faces, because this dome was the first in a series with much improved ventilation, which now works so brilliantly. They had assumed that the peculiar reversal of colour was my deliberate choice because of some special order.

                So now, I am the proud possessor of an avant garde dome with cutting edge technology. It has a beautiful black screen with a soft flock surface. It has a diameter of 5.6 m. it goes up in five minutes and comes down in two seconds. I kid you not.

                Does anyone feel the need to do some experiments?

                Best wishes to you all,

                Ray Worthy.
              • Tom Casey
                The best method for shooting fulldome still content is to go with raw imagery... I will even say, it s the only way. You then get about a 5 f/stop range of
                Message 7 of 20 , Oct 10, 2006
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                  The best method for shooting fulldome still content is to go with raw
                  imagery... I will even say, it's the only way. You then get about a
                  5 f/stop range of values to work with after importing into
                  photoshop. You can adjust for exposure, color temp, work with
                  multiple exposures for specific areas, just about everything and in a
                  16 bit mode. I use an old style light meter, one with the little
                  white "full" dome to measure light in the entire scene... and
                  exposure is always right on, giving me lots of latitude to finish the
                  image in photoshop. You really don't want to limit yourself with the
                  jpeg conversions the camera's do on the fly.

                  With video capture, exposure control is going to be difficult,
                  although some of the new Ultra HD cameras (single lens setup) are
                  promising the ability to get a raw stack of tiff (12 bit) files out
                  of the memory storage... so you might be able to go a similar route
                  as with still content. Any of the multi-lens camera arrangements
                  will have problems if the sun is in a scene (when would it not?)...
                  the lens aimed at the sun will probably create a stitching issue.
                  It's gonna be a tough road on the way to getting good video capture
                  even before you consider the projection issues.

                  Tom


                  ************************************************
                  H o m e R u n P i c t u r e s

                  Tom Casey
                  President & Creative Director

                  100 First Avenue - Suite 450
                  Pittsburgh, PA 15222
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                • Don Davis
                  ... Another 30 year old fantasy, the LED planetarium . The entire dome would be covered with a seamless extremely dense array of lights. Forgetting the
                  Message 8 of 20 , Oct 10, 2006
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                    >I am curious to ask learned Planetarians, like Ed and Don and David et
                    >al, whether they think OLED "domeskins" will arrive to save the day in
                    >terms of black levels?

                    Another 30 year old fantasy, the 'LED planetarium'. The entire dome
                    would be covered with a seamless extremely dense array of lights.
                    Forgetting the harrowing practical considerations, it could be a
                    means to provide amazing brightness range, a sun could be quite
                    bright for instance while showing shadow detail in the same scene if
                    it is in the image. The closest things I see to this are the giant TV
                    displays seen in some cities on the sides of buildings, and they seem
                    to use as few pixels as they can get away with.

                    Don
                  • Ryan Wyatt
                    ... Been to Times Square lately? (I was there just Sunday night, but I suppose I have an advantage in that department.) There are some truly stunning
                    Message 9 of 20 , Oct 10, 2006
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                      Don Davis opined:

                      > The closest things I see to this are the giant TV displays seen in
                      > some cities on the sides of buildings, and they seem to use as few
                      > pixels as they can get away with.

                      Been to Times Square lately? (I was there just Sunday night, but I
                      suppose I have an advantage in that department.) There are some
                      truly stunning displays there, and they're getting better and better
                      all the time. Surprising color uniformity and LED density, even
                      compared to a year ago.

                      Put it this way: we've discussed having an LED display to replace
                      our video wall in the Hall of the Universe.

                      The technology is getting there pretty quickly...


                      Ryan, a.k.a.
                      Ryan Wyatt, Science Visualizer
                      Rose Center for Earth & Space
                      American Museum of Natural History
                      79th Street at Central Park West
                      New York, NY 10024
                    • david mcconville
                      ... Actually, a 44 year old plan, the bulbs are just getting smaller: http://www.bfi.org/node/564 ... The new educational technology will probably provide
                      Message 10 of 20 , Oct 10, 2006
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                        At 06:29 PM 10/10/2006, Don Davis wrote:
                        >Another 30 year old fantasy, the 'LED planetarium'.

                        Actually, a 44 year old plan, the bulbs are just getting smaller:

                        http://www.bfi.org/node/564

                        "... The new educational technology will probably provide also an invention
                        of mine called the Geoscope - a large two-hundred-foot diameter (or more)
                        lightweight geodesic sphere hung hoveringly at one hundred feet above
                        mid-campus by approximately invisible cables from three remote masts. This
                        giant sphere is a miniature earth. Its entire exterior and interior
                        surfaces will be covered with closely-packed electric bulbs, each with
                        variable intensity controls. The lighting of the bulbs is scanningly
                        controlled through an electric computer. The number of the bulbs and their
                        minimum distance of one hundred feet from viewing eyes, either at the
                        center of the sphere or on the ground outside and below the sphere, will
                        produce the visual al effect and resolution of a fine-screen halftone cut
                        or that of an excellent television tube picture. The two-hundred-foot
                        geoscope will cost about fifteen million dollars. It will make possible
                        communication of phenomena that are not at present communicable to man’s
                        conceptual understanding. There are many motion patterns such as those of
                        the hands of the clock or of the solar system planets or of the molecules
                        of gas in a pneumatic ball or of atoms or the earth’s annual weather that
                        cannot be seen or comprehended by the human eye and brain relay and are
                        therefore inadequately comprehended and dealt with by the human mind."

                        ­ from <http://bfi.org/node/400>Education Automation, R. Buckminster
                        Fuller, 1962

                        Discussed in the current technological, scientific, and cultural context in
                        the podcast at http://blog.stranova.com/?p=41


                        --------------------------
                        david mcconville
                        http://www.elumenati.com
                        612.605.0826 x5
                        ----------
                      • Erik Roberts
                        The Geoscope concept is discussed by Bonnie DeVarco and David McConville in this interesting podcast at Stravova:
                        Message 11 of 20 , Oct 11, 2006
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                          The Geoscope concept is discussed by Bonnie DeVarco and David McConville
                          in this interesting podcast at Stravova:

                          http://www.stranova.com/Podcasts/Stranova22.mp3

                          cameraderie
                        • Martin Howe
                          Ed Lantz writes: True. One problem with this approach is that the brightest projectors available are challenged to achieve the 2-3 foot-lamberts of
                          Message 12 of 20 , Oct 11, 2006
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                            Ed Lantz writes:

                            "True. One problem with this approach is that the brightest projectors
                            available are challenged to achieve the 2-3 foot-lamberts of brightness
                            that large-format film deserves. Throwing away 90% of the available
                            light is not a good situation. I also think there may be problems with
                            very dark domes achieving neutral density across all colors. But, as
                            you point out, a darker dome is currently the only way to improve
                            dome-limited contrast."

                            Agree and maybe disagree. I'm not convinced (and I've not yet proved it
                            to myself either way) that 2ftL to 3ftL is the appropriate goal for live
                            action content in a truly dark theatre with the typical screen gain
                            (typically anywhere from 0.3 to 0.7). I agree that very, very low gain
                            screens may prove problematic and it's not particularly efficient!

                            It's (always) about contrast and in particular system contrast. The
                            biggest killer for us (all) is the screen characteristics brought about
                            by its shape and the fact that it is a reflective display system not an
                            emissive one. 10:1 is a good target to shoot for, this is achievable. In
                            our collimated flight simulator systems we typically sign off at around
                            10:1. That means that Civil and Military pilots train on flight
                            simulators with a CR of 10:1. The typical views are terrain, sky and
                            clouds, runway and fields or night flying. This CR is acceptable and
                            provides realistic imagery (for a very fussy audience!!).

                            In some hemispheric systems we have achieved much more, up to 40:1CR but
                            this gives an extremely narrow viewing volume (= very small audience),
                            unrealistic for Fulldome I think.

                            Important to note the measurement approach for this spec though. This CR
                            of 10:1 is measured with a 50/50 checkerboard pattern, not very
                            representative of video. I was always told that average video equivalent
                            'white' content is 40% (I've never taken the time to try to validate
                            this though - any comments?). Normal 'space' content will be lower than
                            this, and this is an important point. It would be interesting to agree
                            test patterns that represent average white content of Fulldome content
                            (live action / space shows / real time).

                            Stephen Dos Remedios over at Chabot did an amazing demonstration of HDR
                            content of images that he shot of a forest scene. Grieg Downing has
                            shown superb HDR content at Denver. These display systems deliver 'only'
                            10:1 CR (checker) and yet this content looks stunning, just like 'being
                            there'. Neither achieve anywhere near 2ftL either.

                            I did take the opportunity at IPS to provoke a well known screen vendor
                            to ask what can be done to screen technology to reduce scatter. He told
                            me that most of the ideas have been tried before and it's too expensive
                            for this market to absorb the development and product costs (if I
                            understood his point correctly).

                            It is true that most of the successful technologies of this market have
                            transferred from other markets that can support the development costs
                            and product volumes (video projectors for instance and playback systems)
                            and I still remain hopeful (maybe naively) that some of the ideas for
                            reducing scatter from reflective hemispheric screens can be implemented
                            - soon.

                            Which brings me onto LED systems...

                            I have had the pleasure of working with outdoor display systems before
                            LED products were commonplace. We spent a lot of time playing with
                            projection systems and screens to manage contrast in an amazingly bright
                            environment - that's where I learnt that contrast is so important. We
                            actually installed a 32 cube rear projected display system outdoors at
                            Piccadilly Circus in London, which worked very well (in the right
                            lighting conditions). We then replaced it with hi-res LED and I sold a
                            few other outdoor LED systems after that too.

                            However LED (good LED) is not at all cheap. However it's main advantage
                            in a dome system would be that it is emissive (it does not depend upon
                            screen reflectance to create the imaging surface). Therefore a lot of
                            treatment can be done to the screen surface to manage scatter (as Ed
                            Lantz rightly points out, just because you use LED you don't get rid of
                            the scatter issue). If you ever get close to an LED display you'll
                            notice that there is a lot of black and not a lot of LED (better to do
                            this when it's off!). My concern about LED (or OLED) is not the
                            practicality of it, it's the price (cost). An LED system suitable for a
                            big outdoor screen is SO different to a hemispheric one indoors in a
                            black room. It will require a dedicated product, developed from the
                            ground up which means R&D $$$'s. So even IF the cost of the little LED
                            comes down to the right $/pixel that doesn't mean to say that the cost
                            of putting them all together in a perfect hemisphere with the correct
                            viewing angle/s and system contrast is realistic.

                            Sorry to be a little pessimistic, I'm naturally an optimist tempered
                            slightly by the scars of reality. We have a bunch of ideas about how to
                            create the perfect Fulldome display system but my spreadsheet just
                            doesn't add up yet to justify the $$$$,s to build a prototype (or two,
                            or three...) just for us Fulldomers. Any backers?

                            Martin

                            Martin Howe
                            Vice President, Visualization
                            SEOS Ltd
                            tel: +44 (0) 1444 870 888
                            mob +44 (0) 7793 414 553
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