Confusion regarding changing CP distances

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Judson Fisher

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Dec 13, 2019, 12:58:30 AM12/13/19
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Hi,
I'm confused about how Hugin is depicting control point distances, especially in that they all seem to change once I save a .pto file and then re-open it.

While setting my control points, in the control point selecter, they were all depicted in some shade of green (I'm aligning an image stack).  Then, after optimization, Hugin reported an average alignment of about 0.5, with a max of only 1 or 2.  BUT if i save the .pto file and then reopen it, it's a totally different story:  Average alignment is closer to 10 with a max of 40 and no amount of resetting or iterations of optimization get anywhere near the originally reported results?

Is this correct? Am I missing something?

I'm attatching my .pto file below just in case it is helpful.

thanks,
/Jud
All_Flights.pto

Luís Henrique Camargo Quiroz

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Dec 13, 2019, 11:37:19 AM12/13/19
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   Hi Jud,

   Did you changed the pano size after optimizations?  By default Hugin chooses a pano of 3000x1500 pels, for a complete equirectangular, and shows the errors relative to this size.

   I also did not understand why my errors "suddenly" increased a lot, but I noticed that I had chosen the final max size for my photos and this changes how the errors are numerically presented.

   This seens your situation: mean ~0.5 for a max 1 or 2 (for 3000x1500, probably) and then (mean) 10 and max 40, perhaps your canvas increased to about 12000x6000?

   Luís Henrique

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Judson Fisher

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Dec 17, 2019, 4:56:12 PM12/17/19
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Luis,

Thank you, I think you are correct. I can see now that control point distance is a function of canvas size and my canvas size does indeed change when I "calculate canvas size."  Thanks for pointing this out, I have only used Hugin for image stack alignment where canvas size is assumed to be the same as the original photo size.

/Jud


On Friday, December 13, 2019 at 8:37:19 AM UTC-8, Luís Henrique Camargo Quiroz wrote:

   Hi Jud,

   Did you changed the pano size after optimizations?  By default Hugin chooses a pano of 3000x1500 pels, for a complete equirectangular, and shows the errors relative to this size.

   I also did not understand why my errors "suddenly" increased a lot, but I noticed that I had chosen the final max size for my photos and this changes how the errors are numerically presented.

   This seens your situation: mean ~0.5 for a max 1 or 2 (for 3000x1500, probably) and then (mean) 10 and max 40, perhaps your canvas increased to about 12000x6000?

   Luís Henrique

Em qui., 12 de dez. de 2019 às 22:58, Judson Fisher <Judson...@humboldt.edu> escreveu:
Hi,
I'm confused about how Hugin is depicting control point distances, especially in that they all seem to change once I save a .pto file and then re-open it.

While setting my control points, in the control point selecter, they were all depicted in some shade of green (I'm aligning an image stack).  Then, after optimization, Hugin reported an average alignment of about 0.5, with a max of only 1 or 2.  BUT if i save the .pto file and then reopen it, it's a totally different story:  Average alignment is closer to 10 with a max of 40 and no amount of resetting or iterations of optimization get anywhere near the originally reported results?

Is this correct? Am I missing something?

I'm attatching my .pto file below just in case it is helpful.

thanks,
/Jud

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A list of frequently asked questions is available at: http://wiki.panotools.org/Hugin_FAQ
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