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Re: [PanoToolsNG] Re: Drum panorama

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  • Bjørn K Nilssen
    ... There s a lot of example photos showing the problems it causes with single-shots in that Wikipedia article I linked to above. And there are tons of other
    Message 1 of 25 , Nov 2, 2011
      På Wed, 02 Nov 2011 23:06:34 +0100, skrev John Riley <johnriley@...>:

      > Thanks Erik, that's interesting. Is the sensor also read sequentially when shooting photos? Would that have the potential to cause problems depending on the physical shutter speed? I have never thought much about that aspect of the reading of the sensor.

      There's a lot of example photos showing the problems it causes with single-shots in that Wikipedia article I linked to above.
      And there are tons of other pages dealing with the rolling-shutter problem and CMOS sensors.
      And there are also (extremely expensive) tools/plugins that can correct some of the problems.

      > John
      >
      > John Riley
      > 4Pi-VR Media Solutions
      > http://4pi-vr.com
      > johnriley@...
      > (h)864-461-3504
      > (c)864-431-7075
      > (w)864-503-5775
      >
      > On Nov 2, 2011, at 5:00 PM, Erik Krause wrote:
      >
      >> Am 02.11.2011 21:51, schrieb John Riley:
      >> >
      >> > Isn't the shutter locked up while shooting video? I don't think those
      >> > shutter are capable of running 30 fps 8-)
      >>
      >> There is no physical shutter of course but since the sensor has to be
      >> read sequentially there is an electronic "shutter".
      >
      >


      --
      Bjørn K Nilssen - bk@... - 3D and panoramas
    • panovrx
      ... I unwrapped a painted vase once for a potter who wanted to make a replica, with a decal transfer, of the vase. I put the vase on a panorama head turntable,
      Message 2 of 25 , Nov 2, 2011
        --- In PanoToolsNG@yahoogroups.com, John Riley <johnriley@...> wrote:
        >
        > I have read about an artist who makes some very cool works using a simulated/computed/extracted technique. In essence, you shoot video of the object while rotating it continuously, extracting the center column of pixels to make a "roll out" image, like you want. There are other, fancier ways you can do things to get awesome artistic effects. A good place to start:
        > http://www.flong.com/texts/lists/slit_scan/
        > That site even has code to automate the process. Even extracting it while shooting, I think. I did a few of them a few years back and it was pretty straightforward. Video quality from your DSLR is so good now that it would look better than back then too.
        >
        > John Riley
        > 4Pi-VR Media Solutions
        > http://4pi-vr.com
        > johnriley@...
        > (h)864-461-3504
        > (c)864-431-7075
        > (w)864-503-5775
        >
        > On Nov 2, 2011, at 9:16 AM, Bjørn K Nilssen wrote:
        >
        > > Often called slit-scan (you'll find lots of links on that with Google)
        > > Traditionally it was made with a camera with a narrow vertical slit, and film passing slowly past that slit while the rotation was synchronized with the turntable with the object on.
        > > I've tried to find an automated solution too, but with no success.
        >

        I unwrapped a painted vase once for a potter who wanted to make a replica, with a decal transfer, of the vase. I put the vase on a panorama head turntable, set it to 5 degrees, and then did 72 shots from straight on, with lighting with polarizers. Then I made a rough 3d CG model of the vase and projected the textures one at a time on the model and rendered a vertical slice from each frame. I stitched them together to make a 360 and mapped that onto the vase to check it looked ok.

        Then the potter took that panoramic image and used a program that makes gores (foldable shapes) whose name I forget and had the transfer made and made the replica. It looked close to the original I thought.

        PeterM
      • Erik Krause
        ... Deshaker for VirtualDub (both freeware) will remove rolling shutter from camera movement, but not from object movement. -- Erik Krause
        Message 3 of 25 , Nov 2, 2011
          Am 02.11.2011 23:22, schrieb Bjørn K Nilssen:
          > And there are also (extremely expensive) tools/plugins that can
          > correct some of the problems.

          Deshaker for VirtualDub (both freeware) will remove rolling shutter from
          camera movement, but not from object movement.

          --
          Erik Krause
          http://www.erik-krause.de
        • Erik Krause
          ... Wouldn t it have been easier to project the images on the vase using a slide or video projector? If the projection lens reproduces the same field of view
          Message 4 of 25 , Nov 2, 2011
            Am 02.11.2011 23:40, schrieb panovrx:
            > I unwrapped a painted vase once for a potter who wanted to make a
            > replica [...]

            Wouldn't it have been easier to project the images on the vase using a
            slide or video projector? If the projection lens reproduces the same
            field of view like the taking lens and you have the vase at the same
            distance you should get the very same image on the vase...

            --
            Erik Krause
            http://www.erik-krause.de
          • panovrx
            I forget the details of the rendering -- maybe I had to choose a particular mapping or unwrapping or baking or something -- sorry 10 years ago :-) ..but it
            Message 5 of 25 , Nov 2, 2011
              I forget the details of the rendering -- maybe I had to choose a particular mapping or unwrapping or baking or something -- sorry 10 years ago :-)
              ..but it worked
              here are the replica vases -- I did 2
              http://www.norman-lindsay.com.au/art/more_teatowels.html

              PeterM

              --- In PanoToolsNG@yahoogroups.com, Erik Krause <erik.krause@...> wrote:
              >
              > Am 02.11.2011 23:40, schrieb panovrx:
              > > I unwrapped a painted vase once for a potter who wanted to make a
              > > replica [...]
              >
              > Wouldn't it have been easier to project the images on the vase using a
              > slide or video projector? If the projection lens reproduces the same
              > field of view like the taking lens and you have the vase at the same
              > distance you should get the very same image on the vase...
              >
              > --
              > Erik Krause
              > http://www.erik-krause.de
              >
            • panovrx
              here is the other vase http://www.normanlindsay.com.au/proddetail.php?prod=101557 the second image of the slideshow shows what the unwrapped texture looked
              Message 6 of 25 , Nov 2, 2011
                here is the other vase
                http://www.normanlindsay.com.au/proddetail.php?prod=101557
                the second image of the slideshow shows what the unwrapped texture looked like

                --- In PanoToolsNG@yahoogroups.com, "panovrx" <panovrx@...> wrote:
                >
                > I forget the details of the rendering -- maybe I had to choose a particular mapping or unwrapping or baking or something -- sorry 10 years ago :-)
                > ..but it worked
                > here are the replica vases -- I did 2
                > http://www.norman-lindsay.com.au/art/more_teatowels.html
                >
                > PeterM
                >
                > --- In PanoToolsNG@yahoogroups.com, Erik Krause <erik.krause@> wrote:
                > >
                > > Am 02.11.2011 23:40, schrieb panovrx:
                > > > I unwrapped a painted vase once for a potter who wanted to make a
                > > > replica [...]
                > >
                > > Wouldn't it have been easier to project the images on the vase using a
                > > slide or video projector? If the projection lens reproduces the same
                > > field of view like the taking lens and you have the vase at the same
                > > distance you should get the very same image on the vase...
                > >
                > > --
                > > Erik Krause
                > > http://www.erik-krause.de
                > >
                >
              • Scott Highton
                Hi Peter, What you re trying to do is the equivalent of a slit scan camera shooting an object on a turntable, as I believe someone else mentioned here. In
                Message 7 of 25 , Nov 2, 2011
                  Hi Peter,

                  What you're trying to do is the equivalent of a slit scan camera shooting an object on a turntable, as I believe someone else mentioned here.  In general, the narrower the slit, the better your results (unless you go to extremes and then wind up with diffraction problems... don't worry about this for the following).  This sort of work has traditionally been done with slit scan camera/turntable systems such as those available from Roundshot (both film and digital) and Panoscan.



                  You can try a similar approach with a low priced digital camera, a slow moving turntable, and some automated scripts (which you'll probably have to create) in Photoshop.

                  Basically, you shoot a series of images as the object rotates, then extract a center column of pixels from each image, and then stack these columns together (like books in a book case) in Photoshop to create a complete 360° flattened view.  Don't try to "stitch" these columns, but rather, simply abut them next to each other.  The more pictures you take (i.e. the smaller the rotation between each), the fewer number of pixels you'll need to extract from the center of each, and the better your resulting image assembly is likely to be.

                  In a perfect world, you'd only take a single pixel column from each image (the equivalent of a single pixel wide slit or image sensor), but that could entail capturing and extracting thousands of images.

                  However, you may find that you can still get great results by shooting fewer images and extracting 10, 20, or 50 pixel wide columns from the center of each.  You'll have to do your own tests to see what works for the size of the object you're shooting and the resolution of the finished image you need.  And you'll have to figure out how many shots are necessary (how much to rotate the object between each shot) for a full rotation in order to maintain the proper aspect ratio for the resulting file when the columns are all stacked together.  Use a telephoto lens for best results.


                  For example, let's say you want a final image that is 3,600 pixels wide.

                  If you were only going to extract a single pixel column for each source image, you'd need 3,600 images, and you'd have to rotate the object 1/10 of a degree between shots.
                  If you could use 10 pixel (wide) columns instead, you'd need only 360 images where the object was rotated one degree between shots.
                  If you could use 20 pixel columns, you'd need 180 images where the object was rotated two degrees between shots.
                  If you could use 50 pixel columns, you'd need 72 images where the object was rotated five degrees between shots.
                  Or, if you could use 100 pixel columns, you'd need only 36 images where the object was rotated 10 degrees between shots.
                  You see the pattern.


                  Bryan Mumford, developer of the Time Machine camera triggering and time lapse system, has a web page that discusses this approach using his Time Machine, a motorized rotary table, and a digital camera.  The Time Machine controls the rotation of the rotary table and the firing of the camera.  He calls this process "Streak Photography," and he's created some beautifully artistic results, including sequences assembled into QT movies.  The same approach should work for capturing and assembling single "unwrapped" object images.




                  Should you decide that you want to pursue a "stitching" approach instead, consider using a telephoto lens and shoot the object from a distance.  This will compress the differences between high and low points on the surface of the drum and minimize visual distortion or foreshortening of the object in each source image.  Then, enter a long focal length, such as 400mm, in PTGui (you may need to override the  EXIF lens info).  That might  better help with control point generation.


                  Good luck with your efforts, and please let us know about your results (post them so we can see, if possible).

                  Regards,




                  Scott Highton
                  Author, Virtual Reality Photography
                       320 pages, 300+ illustrations, $44.95
                       ISBN 978-0-615-34223-8)
                  Web: http://www.vrphotography.com

                • John Riley
                  ... Now, THAT was a crazy ride! Reminds me of my younger days when a friend handed me something and said here, eat this , hehehe. You say Yes, of course ,
                  Message 8 of 25 , Nov 2, 2011


                    On Nov 2, 2011, at 6:20 PM, Erik Krause wrote:

                    Am 02.11.2011 23:06, schrieb John Riley:
                    > Thanks Erik, that's interesting. Is the sensor also read sequentially
                    > when shooting photos?

                    Yes, of course. But it is read after the physical shutter closed, so it 
                    won't have any impact on the image.

                    Video rolling shutter can give very strange effects, but it can be 
                    positively used as well: http://www.youtube.com/watch?v=EnrwrwMfNSs


                    Now, THAT was a crazy ride!  Reminds me of my younger days when a friend handed me something and said "here, eat this", hehehe.

                    You say "Yes, of course", but are you sure about that?  I did a some looking around on the web and I get the impression that DSLRs only use (electronic) rolling shutter when shooting video, but read the whole sensor at once after the shutter closes with stills.

                    Feel free to straighten me out, if need be.

                    John

                    John Riley
                    4Pi-VR Media Solutions
                    http://4pi-vr.com
                    johnriley@...
                    (h)864-461-3504
                    (c)864-431-7075
                    (w)864-503-5775
                  • prague
                    YOu might want to ask Igor Marx how he did this http://www.360cities.net/image/strawberry-panorama
                    Message 9 of 25 , Nov 3, 2011
                      YOu might want to ask Igor Marx how he did this

                      http://www.360cities.net/image/strawberry-panorama




                      --- In PanoToolsNG@yahoogroups.com, "Peter Stephens - PanoTools NG list" <panotoolsng@...> wrote:
                      >
                      > Hi Guys,
                      >
                      > I have been asked to produce a panoramic image of a drum, as if the drum was
                      > sliced down on side and flattened. The idea is to produce a printable image
                      > showing all areas of the cylinder at the same time.
                      >
                      > I have been experimenting with on of my own drums on an object turntable.
                      > I've taken 16 images around it and have been playing around trying to
                      > stitching it together. This particular drum hasn't a huge amount of detail
                      > on it making it nearly impossible to generate control points in PTGui, so
                      > not a great one to experiment with really. I suppose I could put some small
                      > stickers around the outside of it which would help with stitching, might try
                      > that later.
                      >
                      > I'm just wandering if any of you have done this before and have any advise
                      > you can share with me? Cropping the 16 images into a thin strip and
                      > manually stitching it with Photoshop has given me the best results so far,
                      > though not of a quality high enough that I'm happy with. PTGui couldn't
                      > generate control points, so didn't get anywhere with that. Expect I will
                      > get better results with more images taken from different angles, but it's
                      > going to take forever to process by hand. Would be great if I could do this
                      > in PTGui.
                      >
                      > Any help would be appreciated.
                      >
                      >
                      > Pete
                      >
                      > Peter Stephens Photography
                      > www.peterstephens.co.uk
                      > Follow me: <http://www.twitter.com/PJSPhotography> Twitter -
                      > <http://www.facebook.com/PJSPhotography> Facebook -
                      > <http://www.linkedin.com/in/PJSPhotography> Linkedin -
                      > <http://www.flickr.com/peterstephensphotography> Flickr
                      >
                    • Peter Stephens - PanoTools NG list
                      Cool !! gona have to give that a go now ! Pete Peter Stephens Photography www.peterstephens.co.uk From: PanoToolsNG@yahoogroups.com
                      Message 10 of 25 , Nov 3, 2011

                        Cool !!  gona have to give that a go now !

                         

                         

                        Pete

                        Peter Stephens Photography

                        www.peterstephens.co.uk

                         

                        From: PanoToolsNG@yahoogroups.com [mailto:PanoToolsNG@yahoogroups.com] On Behalf Of prague
                        Sent: 03 November 2011 09:53
                        To: PanoToolsNG@yahoogroups.com
                        Subject: [PanoToolsNG] Re: Drum panorama

                         

                         



                        YOu might want to ask Igor Marx how he did this

                        http://www.360cities.net/image/strawberry-panorama

                        --- In PanoToolsNG@yahoogroups.com, "Peter Stephens - PanoTools NG list" <panotoolsng@...> wrote:
                        >
                        > Hi Guys,
                        >
                        > I have been asked to produce a panoramic image of a drum, as if the drum was
                        > sliced down on side and flattened. The idea is to produce a printable image
                        > showing all areas of the cylinder at the same time.
                        >
                        > I have been experimenting with on of my own drums on an object turntable.
                        > I've taken 16 images around it and have been playing around trying to
                        > stitching it together. This particular drum hasn't a huge amount of detail
                        > on it making it nearly impossible to generate control points in PTGui, so
                        > not a great one to experiment with really. I suppose I could put some small
                        > stickers around the outside of it which would help with stitching, might try
                        > that later.
                        >
                        > I'm just wandering if any of you have done this before and have any advise
                        > you can share with me? Cropping the 16 images into a thin strip and
                        > manually stitching it with Photoshop has given me the best results so far,
                        > though not of a quality high enough that I'm happy with. PTGui couldn't
                        > generate control points, so didn't get anywhere with that. Expect I will
                        > get better results with more images taken from different angles, but it's
                        > going to take forever to process by hand. Would be great if I could do this
                        > in PTGui.
                        >
                        > Any help would be appreciated.
                        >
                        >
                        > Pete
                        >
                        > Peter Stephens Photography
                        > www.peterstephens.co.uk
                        > Follow me: <http://www.twitter.com/PJSPhotography> Twitter -
                        > <http://www.facebook.com/PJSPhotography> Facebook -
                        > <http://www.linkedin.com/in/PJSPhotography> Linkedin -
                        > <http://www.flickr.com/peterstephensphotography> Flickr
                        >

                      • Peter Stephens - PanoTools NG list
                        Hi Scott, Thanks…. The drum I was experimenting with was only shot with 16 images so no wander I had issues with it….. also I shot it with an 75mm lens.
                        Message 11 of 25 , Nov 3, 2011

                          Hi Scott,

                           

                          Thanks….  The drum I was experimenting with was only shot with 16 images so no wander I had issues with it…..  also I shot it with an 75mm lens.  Will have another go with far more images and maybe a longer lens.  Loving the time machine photos, need to make some time to try to create some of these cool images.

                           

                          I’ll post my results here for you to see yes.

                           

                          Pete

                           

                          Peter Stephens Photography

                          www.peterstephens.co.uk

                           

                          From: PanoToolsNG@yahoogroups.com [mailto:PanoToolsNG@yahoogroups.com] On Behalf Of Scott Highton
                          Sent: 03 November 2011 00:16
                          To: PanoToolsNG@yahoogroups.com
                          Cc: Peter Stevens
                          Subject: [PanoToolsNG] Re: Drum panorama

                           

                           

                          Hi Peter,

                           

                          What you're trying to do is the equivalent of a slit scan camera shooting an object on a turntable, as I believe someone else mentioned here.  In general, the narrower the slit, the better your results (unless you go to extremes and then wind up with diffraction problems... don't worry about this for the following).  This sort of work has traditionally been done with slit scan camera/turntable systems such as those available from Roundshot (both film and digital) and Panoscan.

                           

                           

                           

                          You can try a similar approach with a low priced digital camera, a slow moving turntable, and some automated scripts (which you'll probably have to create) in Photoshop.

                           

                          Basically, you shoot a series of images as the object rotates, then extract a center column of pixels from each image, and then stack these columns together (like books in a book case) in Photoshop to create a complete 360° flattened view.  Don't try to "stitch" these columns, but rather, simply abut them next to each other.  The more pictures you take (i.e. the smaller the rotation between each), the fewer number of pixels you'll need to extract from the center of each, and the better your resulting image assembly is likely to be.

                           

                          In a perfect world, you'd only take a single pixel column from each image (the equivalent of a single pixel wide slit or image sensor), but that could entail capturing and extracting thousands of images.

                           

                          However, you may find that you can still get great results by shooting fewer images and extracting 10, 20, or 50 pixel wide columns from the center of each.  You'll have to do your own tests to see what works for the size of the object you're shooting and the resolution of the finished image you need.  And you'll have to figure out how many shots are necessary (how much to rotate the object between each shot) for a full rotation in order to maintain the proper aspect ratio for the resulting file when the columns are all stacked together.  Use a telephoto lens for best results.

                           

                           

                          For example, let's say you want a final image that is 3,600 pixels wide.

                           

                          If you were only going to extract a single pixel column for each source image, you'd need 3,600 images, and you'd have to rotate the object 1/10 of a degree between shots.

                          If you could use 10 pixel (wide) columns instead, you'd need only 360 images where the object was rotated one degree between shots.

                          If you could use 20 pixel columns, you'd need 180 images where the object was rotated two degrees between shots.

                          If you could use 50 pixel columns, you'd need 72 images where the object was rotated five degrees between shots.

                          Or, if you could use 100 pixel columns, you'd need only 36 images where the object was rotated 10 degrees between shots.

                          You see the pattern.

                           

                           

                          Bryan Mumford, developer of the Time Machine camera triggering and time lapse system, has a web page that discusses this approach using his Time Machine, a motorized rotary table, and a digital camera.  The Time Machine controls the rotation of the rotary table and the firing of the camera.  He calls this process "Streak Photography," and he's created some beautifully artistic results, including sequences assembled into QT movies.  The same approach should work for capturing and assembling single "unwrapped" object images.

                           

                           

                           

                           

                          Should you decide that you want to pursue a "stitching" approach instead, consider using a telephoto lens and shoot the object from a distance.  This will compress the differences between high and low points on the surface of the drum and minimize visual distortion or foreshortening of the object in each source image.  Then, enter a long focal length, such as 400mm, in PTGui (you may need to override the  EXIF lens info).  That might  better help with control point generation.

                           

                           

                          Good luck with your efforts, and please let us know about your results (post them so we can see, if possible).

                           

                          Regards,

                           

                           

                           

                           

                          Scott Highton

                          Author, Virtual Reality Photography

                               320 pages, 300+ illustrations, $44.95

                               ISBN 978-0-615-34223-8)

                          Web: http://www.vrphotography.com

                           

                        • Michel Thoby
                          ... I had posted a page about what I think is a closely related matter. I have converted some QTVR old files to supplement them in Flash. Hoping it all works
                          Message 12 of 25 , Nov 3, 2011

                            Le 3 nov. 2011 à 10:53, prague a écrit :

                            YOu might want to ask Igor Marx how he did this

                            http://www.360cities.net/image/strawberry-panorama

                            I had posted a page about what I think is a closely related matter. I have converted some QTVR old files to supplement them in Flash. Hoping it all works right:

                            Michel
                          • Erik Krause
                            ... It isn t possible technically to read the whole sensor at once. You would need one A/D converter for each sensor cell, not to speak of the processor which
                            Message 13 of 25 , Nov 3, 2011
                              Am 03.11.2011 04:10, schrieb John Riley:
                              > I get the impression that DSLRs only use (electronic) rolling shutter
                              > when shooting video, but read the whole sensor at once after the shutter
                              > closes with stills.

                              It isn't possible technically to read the whole sensor at once. You
                              would need one A/D converter for each sensor cell, not to speak of the
                              processor which would need to run several million tasks in parallel. You
                              can't even read all scan lines in parallel.

                              read
                              http://en.wikipedia.org/wiki/Active_pixel_sensor#Array
                              and
                              http://en.wikipedia.org/wiki/Charge-coupled_device#Frame_transfer_CCD

                              However, since the physical shutter moves at limited speed you get a
                              rolling shutter effect anyway. If you shoot at exposure times faster
                              than shortest flash sync (1/250s usually) only a slit moves across the
                              sensor. See f.e. http://www.youtube.com/watch?v=ptfSW4eW25g

                              --
                              Erik Krause
                              http://www.erik-krause.de
                            • prague
                              then how does a Global Shutter work?
                              Message 14 of 25 , Nov 4, 2011
                                then how does a Global Shutter work?



                                --- In PanoToolsNG@yahoogroups.com, Erik Krause <erik.krause@...> wrote:
                                >
                                > Am 03.11.2011 04:10, schrieb John Riley:
                                > > I get the impression that DSLRs only use (electronic) rolling shutter
                                > > when shooting video, but read the whole sensor at once after the shutter
                                > > closes with stills.
                                >
                                > It isn't possible technically to read the whole sensor at once. You
                                > would need one A/D converter for each sensor cell, not to speak of the
                                > processor which would need to run several million tasks in parallel. You
                                > can't even read all scan lines in parallel.
                                >
                                > read
                                > http://en.wikipedia.org/wiki/Active_pixel_sensor#Array
                                > and
                                > http://en.wikipedia.org/wiki/Charge-coupled_device#Frame_transfer_CCD
                                >
                                > However, since the physical shutter moves at limited speed you get a
                                > rolling shutter effect anyway. If you shoot at exposure times faster
                                > than shortest flash sync (1/250s usually) only a slit moves across the
                                > sensor. See f.e. http://www.youtube.com/watch?v=ptfSW4eW25g
                                >
                                > --
                                > Erik Krause
                                > http://www.erik-krause.de
                                >
                              • Erik Krause
                                ... In still photography any non-focal-plane shutter is a global one. For video apparently CCD sensors don t suffer from rolling shutter (which was new to me):
                                Message 15 of 25 , Nov 6, 2011
                                  Am 04.11.2011 15:57, schrieb prague:
                                  > then how does a Global Shutter work?

                                  In still photography any non-focal-plane shutter is a global one. For
                                  video apparently CCD sensors don't suffer from rolling shutter (which
                                  was new to me): http://www.dvxuser.com/jason/CMOS-CCD/

                                  --
                                  Erik Krause
                                  http://www.erik-krause.de
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