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Flat scan distortion not working

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  • Sepp Spenlinhauer
    SO I have my 20th high school reunion coming up and I wanted to print out a copy of the (4) large all school photos that were taken with everyone standing on
    Message 1 of 5 , Apr 14 9:49 AM
      SO I have my 20th high school reunion coming up and I wanted to print out a copy of the (4) large all school photos that were taken with everyone standing on semi-circular bleachers with a moving camera. It was a very cool experience - but trying to stitch the three scans of the images has not.
      I have read the FAQ about setting the FOV to 1° and not optimizing it, but despite the fact that I think this is a very simple thing to do, PTgui is warping the photos rather than rotating them to align.
      It is finding excellent control points, and I have added a couple more, but when I look at the resulting layers in photoshop they aren't even CLOSE....

      The optimizer is constantly returning BAD or not very good...

      If PTgui can't handle the flat scanner alignment, which program could?
      Is it the FOV that is affecting this? is there another setting that I can adjust to get this "basic" alignment?

      I have played around with just moving the layers in photoshop, but they are just off enough that it is not easy.
      If I were to use manual control points would this help?
      Since there are no architectural elements in the photo, which is in a field, I can't really align or distort with anything fixed.

      Or is there another program I should look at for this type of alignment?



      THanks SEPP!
    • Gerald Lodron
      PTGUI normally takes good control points, the only thing you must to do is to check if the control points are on fixed objects (no moving clouds or persons
      Message 2 of 5 , Apr 14 10:37 AM
        PTGUI normally takes good control points, the only thing you must to do is to check if the control points are on fixed objects (no moving clouds or persons etc, DONT USE CONTROLPOINTS TO CORRECT STITCHING ERRORS CAUSED BY MOVEMENTS). The second thing is to check if the points are well distributed over the overlapping images (thats not so important but will enhance the result a little bit). And for sure, first check the cropping.

        Did you use a nodal point adapter when making the images? When not then it is possible that you get stitching errors on objects which are near the camera (see wikipedia for nodal point explanation). If you have near objects it is nearly impossible to make get good results without nodal point adapter. You can use the smartblend blender from panotools as an alternative blender which is very good in correcting such things, but big it does not always work, so you must correct them with photoshop tricks.

        Another hint for making stiched panos: Use manual mode with constant aperture, exposure time, manual white point AND FIXED FOCUS FOR ALL images.

        Maybe you send a small image of the result, maybe we have another hint when we see the image?

        I hope I said everything correct, I am also a newbe,
        best regards,




        ________________________________
        From: Sepp Spenlinhauer <seppspenlinhauer@...>
        To: PanoToolsNG@yahoogroups.com
        Sent: Tuesday, April 14, 2009 6:49:01 PM
        Subject: [PanoToolsNG] Flat scan distortion not working





        SO I have my 20th high school reunion coming up and I wanted to print out a copy of the (4) large all school photos that were taken with everyone standing on semi-circular bleachers with a moving camera. It was a very cool experience - but trying to stitch the three scans of the images has not.
        I have read the FAQ about setting the FOV to 1° and not optimizing it, but despite the fact that I think this is a very simple thing to do, PTgui is warping the photos rather than rotating them to align.
        It is finding excellent control points, and I have added a couple more, but when I look at the resulting layers in photoshop they aren't even CLOSE....

        The optimizer is constantly returning BAD or not very good...

        If PTgui can't handle the flat scanner alignment, which program could?
        Is it the FOV that is affecting this? is there another setting that I can adjust to get this "basic" alignment?

        I have played around with just moving the layers in photoshop, but they are just off enough that it is not easy.
        If I were to use manual control points would this help?
        Since there are no architectural elements in the photo, which is in a field, I can't really align or distort with anything fixed.

        Or is there another program I should look at for this type of alignment?

        THanks SEPP!







        [Non-text portions of this message have been removed]
      • John Houghton
        ... You should not be optimizing fov,a,b and c, so there should be no obvious warping. Optimizing one of the shear parameters (g or t) might be helpful since
        Message 3 of 5 , Apr 14 11:28 AM
          --- In PanoToolsNG@yahoogroups.com, "Sepp Spenlinhauer" <seppspenlinhauer@...> wrote:
          >
          > I have read the FAQ about setting the FOV to 1° and not optimizing it, but despite the fact that I think this is a very simple thing to do, PTgui is warping the photos rather than rotating them to align.

          You should not be optimizing fov,a,b and c, so there should be no obvious warping. Optimizing one of the shear parameters (g or t) might be helpful since these are scanned images. Otherwise, ensure all the images are cropped to exactly the same size, fix y,p and r of one image and optimize y,p,r of the other images.

          If you include the edges of the original photos in the scans, you could use line control points (t3,t4 etc) on these to help with the alignment. (Need to use the Panorama Tools optimizer in this case).

          John
        • Sepp Spenlinhauer
          John, Thanks for the pointers. I had not thought of making sure that all the scans were the same size. That did the trick! I had already tried leveling the
          Message 4 of 5 , Apr 14 9:13 PM
            John,

            Thanks for the pointers. I had not thought of making sure that all the scans were the same size. That did the trick!

            I had already tried leveling the image, but it was not helping.

            Gerald,
            This is a scan of a photo, there are no nodal points.
            I have done some advanced stitching and own a nodal ninja, so I am very familiar with getting good panos, and that is why I was so frustrated.
            Of course I overlooked a very simple thing!

            If the Website moderators read this, they should add that little reminder to the website FAQ - that scanned images need to be the same size... I thought that PTgui would give the user a notice if the images weren't all the same size?

            Thanks for the help.

            SEPP!
          • Sepp Spenlinhauer
            I uploaded a link to the image...Its a big image. www.eclecticprecision.com/GDA-1988.jpg (That s me, 3rd row down from the top, 7th in from the right side,
            Message 5 of 5 , Apr 15 8:00 PM
              I uploaded a link to the image...Its a "big" image.

              www.eclecticprecision.com/GDA-1988.jpg

              (That's me, 3rd row down from the top, 7th in from the right side, wearing a
              white shirt, between the girl with the brown vest and the guy in blue
              shirt.)

              It was a moving camera panorama with the film moving in the opposite
              direction. It was a "long" exposure and that is why some things are
              "blurry". Some "kids" moved their hands - we were told to be still. If you
              look at the angle of the shadows, it might help explain that we are in
              standing on semi-circular bleachers so that we are all the same distance
              from the camera.

              One year, a kid stood at one end, then when the photographer signaled, he
              ran behind everyone and stood at the other end, and was in the same photo
              twice!
              Its no big deal these days with digital photos and everything, but remember,
              this was 1988!!!!

              Thanks again,

              SEPP!

              _____

              From: PanoToolsNG@yahoogroups.com [mailto:PanoToolsNG@yahoogroups.com] On
              Behalf Of Sepp Spenlinhauer
              Sent: April 15, 2009 12:13
              To: PanoToolsNG@yahoogroups.com
              Subject: [PanoToolsNG] Re: Flat scan distortion not working - SOLVED





              John,

              Thanks for the pointers. I had not thought of making sure that all the scans
              were the same size. That did the trick!

              I had already tried leveling the image, but it was not helping.

              Gerald,
              This is a scan of a photo, there are no nodal points.
              I have done some advanced stitching and own a nodal ninja, so I am very
              familiar with getting good panos, and that is why I was so frustrated.
              Of course I overlooked a very simple thing!

              If the Website moderators read this, they should add that little reminder to
              the website FAQ - that scanned images need to be the same size... I thought
              that PTgui would give the user a notice if the images weren't all the same
              size?

              Thanks for the help.

              SEPP!






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