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Re: Consistent stitching errors

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  • Alessandro Ugazio
    Blake, I ve seen your pano and I have some workflow suggestions: - be sure all your shots (including zenith and nadir) are _really_ vertical, or portrait mode;
    Message 1 of 8 , Nov 30, 2006
      Blake, I've seen your pano and I have some workflow suggestions:

      - be sure all your shots (including zenith and nadir) are _really_ vertical, or portrait mode;
      if you zenith or nadir are horizontal, rotate them in Photoshop and resave them.
      - set vertical cps not only in anchor image but also in other images every about 90
      degrees in the scene;
      - optimizing, check yaw, pitch and roll for every image and uncheck only yaw for
      anchor image (I use PTMac, don't know how PTGui appears but it should be the same)

      I usually optimize first only for image position, deleting just very high values (90 or more,
      but not 30-40, for example)
      Then I optimize for position + fov (at this point the distance should be strongly reduced),
      then pos+fov+b, then pos+fov+a,b,d,e.
      During these steps I try to keep the more cps I can, and I usually end up with about 3 or 4
      maximum cp distance.

      I have an old Panosaurus not perfectly set up, and a cheap quick-release plate (brand
      Kaiser!...) that produces a remarkable camera inclination in every image; nevertheless, I
      usually obtain satisfying results after described optimization.

      The main issues I have are enblend misalignments that I mask out in Photoshop (I always
      generate an enblend tiff, keeping single layers to play with in PS).

      Another thing I usually do: I shot two nadirs with panohead visible, and then a "free" nadir
      to close the gap; then I merge them in PS and generate a nadir that stitches well with other
      images. I save a lot of time since I begun doing like this.

      I have different camera and lens (Nikon D50+Nikkor 10.5), but even though Panosaurus
      isn't a perfect tool I hope you can obtain aligned panos with your actual gear.

      These are mine:
      <http://www.ziouga.it/Panorami/Panorami.html>

      ciao
      Alessandro Ugazio
    • John Houghton
      ... This suggests that the lateral positioning of the camera is not correct. The entrance pupil may be located correctly front to back, but not side to side.
      Message 2 of 8 , Nov 30, 2006
        --- In PanoToolsNG@yahoogroups.com, Blake Michaelson
        <blake.michaelson@...> wrote:
        >
        > Imagine a nautilus shell put on its side, and shifted 60° about
        > it's "nodal point" - there's a bit of a lip from each pano image
        > that contributes to making the circle look a bit like a pinwheel...
        > if you can imagine what I'm attempting to describe.

        This suggests that the lateral positioning of the camera is not
        correct. The entrance pupil may be located correctly front to back,
        but not side to side. Whatever instructions you are following, they
        don't seem to have worked. Try checking the entrance pupil position
        visually using this simple arrangement:
        http://homepage.ntlworld.com/j.houghton/eppos.jpg
        Point the eyepiece at a bright light source to illuminate the
        entrance pupil. Make sure you have the pano head level and use the
        plumb line to check that the entrance pupil is centered on the axis
        point.

        Generally, there is no requirement to accurately level the panorama
        head and/or the camera to ensure good stitching. Rotating the camera
        about the no-parallax point is the important thing to get right.

        John
      • Sacha Griffin
        There s no way to know really without the original images and your project file where the flaw is in your system. I ve used an identical setup as yours, and
        Message 3 of 8 , Nov 30, 2006
          There's no way to know really without the original images and your project
          file where the flaw is in your system.

          I've used an identical setup as yours, and consistently get under 1 pixel of
          error average with a max error of no more than 1.5 or 2.

          There are literally a dozen or more points of failure and this could turn
          into a dangerous thread of conjecture.

          You can browse past messages here for many many useful hints but I advise to
          post everything somewhere so we can take a look.

          Sacha Griffin
          Southern Digital Solutions LLC
          www.southern-digital.com
          www.seeit360.net
          www.ezphotosafe.com
          404-551-4275
          404-731-7798


          -----Original Message-----
          From: Blake Michaelson [mailto:blake.michaelson@...]
          Sent: Thursday, November 30, 2006 3:57 AM
          To: PanoToolsNG@yahoogroups.com
          Subject: [PanoToolsNG] Consistent stitching errors

          Hello,

          I've been searching for a resolution to some consistent stitching errors
          without success - I'm hoping I can gain some insight from some of the
          sage here... Forgive me if this is a bit lengthy, but I wanted to
          ensure I accurately represented the issue.

          I am using a Canon 350D with the Peleng 8mm EOS, a Panosaurus head,
          Bogen 3012B Legs and 486RC2 (with RC2 removable plate) - my first
          instinct is to immediately jump on the panosaurus as the culprit, but I
          don't want to be too quick to judge.

          The consistent problem I am having with the stitching errors is that,
          regardless of the number of images I take (4/6/8/12) I have a
          significant amount of deviation on my control point table. Were I to
          take 4 shots plus Z & N, import them into PTGui (basic mode) and align
          them - my results would be: Average control point distance 8.3524,
          minimum 0.6301, maximum 30.7133 - this is a typical spread for any given
          series of images. Although this isn't too detrimental when taking
          outdoor panos, it is a significant issue when taking indoor panos.

          I have found that I can decrease the spread, i.e. improve the tightness
          of the table, by removing and nadir - marginally, but some - say an
          average of 5.0 for the control points, and a little bit more by removing
          the zenith. The biggest gain is accomplished by simply removing the nadir.

          I have attempted to clean up my control point table by deleting high
          value points, and re-optimizing the table, eventually ending up with
          very few control points, but a "very good" optimization with a max
          distance control point of less than 5.0. Regardless, the same stitching
          issues remain.

          The actual stitching issue is typically a highly visible vertical
          "smudge" or alignment issue on a horizontal surface (i.e. a ceiling
          seam, a structural beam) or simply a skewed vertical stitch placed in
          the middle of a cabinet or wall. As an aside - I had nearly no such
          issues with the same legs, head, camera setup using the 18-55 kit lens
          set to 18mm using 3 rows of 12 shots - 36 pictures with the kit lens
          stitched better than 6 using the peleng! (sample at
          http://www.nwpropertyphotos.com/)

          I've attempted to attach a copy of a nadir from a 6 shot pano - in the
          event it doesn't attach, the picture depicts the base of the panosaurus
          (a circle) displayed as though there are parallax problems. Imagine a
          nautilus shell put on its side, and shifted 60° about it's "nodal point"
          - there's a bit of a lip from each pano image that contributes to making
          the circle look a bit like a pinwheel... if you can imagine what I'm
          attempting to describe.

          The few thoughts that came to mind:
          - I've incorrectly calibrated the lens/head - I followed the
          instructions precisely, and have come up with the same result on many
          attempts over the last few weeks (17.2 on the far left DSLR scale)
          - Somehow the panosaurus is not rotating precisely and I'm getting
          paralax regardless of calibration
          - There is a flaw in my workflow
          - I'm expecting too much from PTGui
          - I'm expecting too much from my gear

          Any thoughts would be greatly appreciated - I've seen so many fantastic
          panos here and I wish I could share similar great work myself!!!

          I'd be happy to post any files you feel may be salient to this topic.

          I'm also thinking its time to step up to a more substantial pano head -
          any sub-$500US suggestions without locking into a body/lens combo like
          the 360P?

          Thanks in advance,
          Blake


          [Non-text portions of this message have been removed]



          --

          Yahoo! Groups Links
        • Blake Michaelson
          Thank you all for the excellent information! I tore down my system (Canon 350D / Peleng 8mm / Panosaurus - for the next guy who searches for this issue) and
          Message 4 of 8 , Dec 1, 2006
            Thank you all for the excellent information! I tore down my system
            (Canon 350D / Peleng 8mm / Panosaurus - for the next guy who searches
            for this issue) and set it all up once again (I have to admit that the
            link below to eppos.jpg was a nice simplistic approach to checking the
            alignment). I took another 4+1+2 (2 nadir opposed 180°), things
            stitched a little better, but not much different than before.

            However, I did have GREAT success with going into advanced mode of
            PTGui, selecting the Optimizer tab, keeping the Optimizer in simple
            mode, selecting optimize lens Field of View, and selecting Minimize lens
            distortion to "Heavy + lens shift", then ran the optimizer. I ended up
            with an average of 1.03, max of 2.47 and min 0.04 - significantly better
            points, and subsequently significantly better stitched panos! This
            almost completely eliminated the "nautilus" effect with regard to the
            unpatched nadir. I went back and restitched some panos I took prior to
            realigning my setup and they stitched just as precisely as well...

            Thanks for the all the continued assistance - I appreciate it tremendously!

            Blake

            John Houghton wrote:
            >
            > --- In PanoToolsNG@yahoogroups.com
            > <mailto:PanoToolsNG%40yahoogroups.com>, Blake Michaelson
            > <blake.michaelson@...> wrote:
            > >
            > > Imagine a nautilus shell put on its side, and shifted 60° about
            > > it's "nodal point" - there's a bit of a lip from each pano image
            > > that contributes to making the circle look a bit like a pinwheel...
            > > if you can imagine what I'm attempting to describe.
            >
            > This suggests that the lateral positioning of the camera is not
            > correct. The entrance pupil may be located correctly front to back,
            > but not side to side. Whatever instructions you are following, they
            > don't seem to have worked. Try checking the entrance pupil position
            > visually using this simple arrangement:
            > http://homepage.ntlworld.com/j.houghton/eppos.jpg
            > <http://homepage.ntlworld.com/j.houghton/eppos.jpg>
            > Point the eyepiece at a bright light source to illuminate the
            > entrance pupil. Make sure you have the pano head level and use the
            > plumb line to check that the entrance pupil is centered on the axis
            > point.
            >
            > Generally, there is no requirement to accurately level the panorama
            > head and/or the camera to ensure good stitching. Rotating the camera
            > about the no-parallax point is the important thing to get right.
            >
            > John
            >
            >
          • Roger D. Williams
            Blake, I am so glad you got what you needed. As a moderator of the list I must say it gives the very greatest satisfaction to think that we have such
            Message 5 of 8 , Dec 1, 2006
              Blake, I am so glad you got what you needed. As a moderator of the
              list I must say it gives the very greatest satisfaction to think
              that we have such knowledgeable and helpful people in the group.
              I am only a few years ahead of you, and still groping around near
              the bottom of the learning curve but I would still be trying to
              warp images in PaintShop pro if it weren't for this list!

              Roger W.

              On Fri, 01 Dec 2006 17:07:07 +0900, Blake Michaelson
              <blake.michaelson@...> wrote:

              > Thank you all for the excellent information! I tore down my system
              > (Canon 350D / Peleng 8mm / Panosaurus - for the next guy who searches
              > for this issue) and set it all up once again (I have to admit that the
              > link below to eppos.jpg was a nice simplistic approach to checking the
              > alignment). I took another 4+1+2 (2 nadir opposed 180°), things
              > stitched a little better, but not much different than before.
              >
              > However, I did have GREAT success with going into advanced mode of
              > PTGui, selecting the Optimizer tab, keeping the Optimizer in simple
              > mode, selecting optimize lens Field of View, and selecting Minimize lens
              > distortion to "Heavy + lens shift", then ran the optimizer. I ended up
              > with an average of 1.03, max of 2.47 and min 0.04 - significantly better
              > points, and subsequently significantly better stitched panos! This
              > almost completely eliminated the "nautilus" effect with regard to the
              > unpatched nadir. I went back and restitched some panos I took prior to
              > realigning my setup and they stitched just as precisely as well...
              >
              > Thanks for the all the continued assistance - I appreciate it
              > tremendously!

              --
              Work: www.adex-japan.com
              Play: www.usefilm.com/member/roger
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