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[PanoToolsNG] Re: Nadir editing...

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  • Keith Martin
    ... My instinct would be to avoid scaling past the suggested maximum size. That would probably involve recalculating the bitmap content past the actual
    Message 1 of 25 , Oct 5, 2008
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      Sometime around 5/10/08 (at 17:27 +0200) Erik Krause said:

      >Check "Maximum Size" in "Set optimum size" on create panorama tab and
      >possibly even a bit larger.

      My instinct would be to avoid scaling past the suggested maximum
      size. That would probably involve recalculating the bitmap content
      past the actual captured level of detail, and it might involve
      slightly more recalculation softening than the specific 'max size'
      output would produce.

      Although this is just an instinctive reaction based on some
      experience with more traditional (i.e. non-pano) image resizing
      caveats and pitfalls.


      > Uncheck "Use fast transform".

      Is there a way to make that option default to off? I virtually always
      uncheck it, so I'd rather make it off from the start.


      k
    • Erik Krause
      ... Since you remap to rectilinear the image is always heavily recalculated. If you chose Maximum size you get a rectilinear result image where the
      Message 2 of 25 , Oct 5, 2008
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        Am Sunday, October 05, 2008 um 18:10 schrieb Keith Martin:

        > >Check "Maximum Size" in "Set optimum size" on create panorama tab and
        > >possibly even a bit larger.
        >
        > My instinct would be to avoid scaling past the suggested maximum
        > size. That would probably involve recalculating the bitmap content
        > past the actual captured level of detail, and it might involve
        > slightly more recalculation softening than the specific 'max size'
        > output would produce.

        Since you remap to rectilinear the image is always heavily
        recalculated. If you chose "Maximum size" you get a rectilinear
        result image where the resolution in the image center is exactly the
        same as for the equirect equator (equirect width / pi). Outside the
        center pixels are stretched anyway.

        That's why it is important not to compress pixels in the image
        center, since this information will be lost if remapped back into
        equirect. Panotools and PTGui use pretty sophisticated interpolators,
        which always a greater surrounding of the source pixel to calculate a
        destination pixel.

        The anti-aliasing interpolators in panotools (and most likely the
        PTGui interpolators, too) guarantee that there is no information lost
        if you enlarge, hence it might be better to enlarge slightly in order
        to have all information available when reducing again.

        > > Uncheck "Use fast transform".
        >
        > Is there a way to make that option default to off? I virtually always
        > uncheck it, so I'd rather make it off from the start.

        Should be possible if you use "Make default" (File menu)

        best regards
        --
        Erik Krause
        Offenburger Str. 33
        79108 Freiburg
      • Sacha Griffin
        I did some checking into the interpolators used. Panotools Lanczos were just barely distinguishable from the source. Ptgui lanczos had the sharpening effect.
        Message 3 of 25 , Oct 5, 2008
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          I did some checking into the interpolators used.

          Panotools Lanczos were just barely distinguishable from the source.

          Ptgui lanczos had the sharpening effect. However ptools lanczos took about
          10 times the amount of time.

          Probably using one of the bicubics is going to be best.

          I don't think fast transform disabled is probably going to be worth the
          effect versus noticability.





          Sacha Griffin

          Southern Digital Solutions LLC

          http://www.southern-digital.com

          http://www.seeit360.net

          404-551-4275







          From: PanoToolsNG@yahoogroups.com [mailto:PanoToolsNG@yahoogroups.com] On
          Behalf Of Erik Krause
          Sent: Sunday, October 05, 2008 3:15 PM
          To: PanoToolsNG@yahoogroups.com
          Subject: [PanoToolsNG] Re: Nadir editing...



          Am Sunday, October 05, 2008 um 18:10 schrieb Keith Martin:

          > >Check "Maximum Size" in "Set optimum size" on create panorama tab and
          > >possibly even a bit larger.
          >
          > My instinct would be to avoid scaling past the suggested maximum
          > size. That would probably involve recalculating the bitmap content
          > past the actual captured level of detail, and it might involve
          > slightly more recalculation softening than the specific 'max size'
          > output would produce.

          Since you remap to rectilinear the image is always heavily
          recalculated. If you chose "Maximum size" you get a rectilinear
          result image where the resolution in the image center is exactly the
          same as for the equirect equator (equirect width / pi). Outside the
          center pixels are stretched anyway.

          That's why it is important not to compress pixels in the image
          center, since this information will be lost if remapped back into
          equirect. Panotools and PTGui use pretty sophisticated interpolators,
          which always a greater surrounding of the source pixel to calculate a
          destination pixel.

          The anti-aliasing interpolators in panotools (and most likely the
          PTGui interpolators, too) guarantee that there is no information lost
          if you enlarge, hence it might be better to enlarge slightly in order
          to have all information available when reducing again.

          > > Uncheck "Use fast transform".
          >
          > Is there a way to make that option default to off? I virtually always
          > uncheck it, so I'd rather make it off from the start.

          Should be possible if you use "Make default" (File menu)

          best regards
          --
          Erik Krause
          Offenburger Str. 33
          79108 Freiburg





          [Non-text portions of this message have been removed]
        • Erik Krause
          ... Interesting! Did you test lanczos2 or lanczos3 with panotools? They should both sharpen slightly, but lanczos3 more than lanczos2. ... If you assemble
          Message 4 of 25 , Oct 6, 2008
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            Am Sunday, October 05, 2008 um 21:38 schrieb Sacha Griffin:

            > Panotools Lanczos were just barely distinguishable from the source.
            >
            > Ptgui lanczos had the sharpening effect. However ptools lanczos took about 10
            > times the amount of time.

            Interesting! Did you test lanczos2 or lanczos3 with panotools? They
            should both sharpen slightly, but lanczos3 more than lanczos2.

            > Probably using one of the bicubics is going to be best.
            >
            > I don't think fast transform disabled is probably going to be worth the
            > effect versus noticability.

            If you assemble cubefaces to equirect with Fast Transform on you get
            tiny black triangles in the corners...

            best regards
            --
            Erik Krause
            Offenburger Str. 33
            79108 Freiburg
          • Sacha Griffin
            Probably 3, I didn t notice any sharpening effect unlike ptgui lanczos which admittedly is a little extreme. I don t imagine a case where ll Ill need to go
            Message 5 of 25 , Oct 6, 2008
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              Probably 3, I didn't notice any sharpening effect unlike ptgui lanczos which
              admittedly is a little extreme.
              I don't imagine a case where'll Ill need to go from cubefaces to
              equirectangular. At least in my workflow.
              The corners would be the edge of the image, which wouldn't be retouched. I
              mask a little bit the remapped retouch by selecting the black and expanding
              some pixels and creating a mask. Some time ago someone pointed out I
              shouldn't be using the associated alpha channel, and eliminate that step,
              and now I imagine doing so would require deselecting fast transform. Cut
              time some place and add it somewhere else. :)

              On Mon, Oct 6, 2008 at 1:34 PM, Erik Krause <erik.krause@...> wrote:

              > Am Sunday, October 05, 2008 um 21:38 schrieb Sacha Griffin:
              >
              >
              > > Panotools Lanczos were just barely distinguishable from the source.
              > >
              > > Ptgui lanczos had the sharpening effect. However ptools lanczos took
              > about 10
              > > times the amount of time.
              >
              > Interesting! Did you test lanczos2 or lanczos3 with panotools? They
              > should both sharpen slightly, but lanczos3 more than lanczos2.
              >
              > > Probably using one of the bicubics is going to be best.
              > >
              > > I don't think fast transform disabled is probably going to be worth the
              > > effect versus noticability.
              >
              > If you assemble cubefaces to equirect with Fast Transform on you get
              > tiny black triangles in the corners...
              >
              > best regards
              > --
              > Erik Krause
              > Offenburger Str. 33
              > 79108 Freiburg
              >
              >
              >



              --

              Sacha Griffin
              Southern Digital Solutions LLC
              http://www.southern-digital.com
              http://www.seeit360.net
              404-551-4275


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