Dark line at +/-180° on some circular pano

The file dark_line.jpg was added: Vertical dark line in Quicktime rendering

I solve the problem by turning my pano about few degrees.
File Added: preview_dark_line.jpg

The file preview_dark_line.jpg was added: Hugin preview showing a picture near -/+180° limit

can you elaborate / give more detail? are these full sphericals? and are their pixel dimensions X = 2*Y when there is a black line? and when there is no? can you provide a set of images and two .pto files, one that generates the dark line and one that does not? do you see the black line also when looking at the panorama in a local viewer such as FSPViewer?

Please find samples in the following folder :

http://geek86.free.fr/panophoto/bug/

I mostly observed it for circular/cylinder pano. I did not checked for spherical ones. I don't think it is a matter of the renderer because you can check on the generated tiff file that pixels colors near the right/left borders are already not consistent.

If you have more question, don't hesitate. I will try to answer faster...

Test were done with Windows XP Home SP 3 ia32. It still exists with the latest Hugin version (2009.4.0).

Hi are you scaling these images in Photoshop?

Photoshop has a known bug that produces exactly this problem, the workaround is to remove the alpha channel before resizing.

Not, I don't scale the images. Usually, I use .tif file from RAW (Olympus Raw File converted with Olympus Studio 2). But in this case, I also checked with jpg direct from DSLR (the files provided in the link bellow). So TIF or JPG, I get the dark line.

Sorry, I meant the images created by Hugin not the input photos.

No scaling after generation by Hugin. Usually, I remove the alpha channel with Gimp. But dark line is present with or without alpha channel.

This is an enblend bug. Enblend sometimes takes along pixels from the "black" (but alpha=0) pixels outside the remapped area.

The question is what enblend can do about the "wraparound" area. For a good blend, it needs access to pixels "beyond the edge".

(for storing as a cylindrical projection image, it doesn't really matter that much, but as postprocessing people might want to put it in a VR tool or something where the seam at 0/360 or -180/180 becomes important. )

Anyway, The only thing I can think of to fix this easily would be for Nona (or other remappers) to generate an output image canvas from -190 to +190 and then later cropping at -180 - +180. (i.e. duplicating pixels between +170/-190 to +180 and from -180 to -170 (+190).

This shouldn't be a problem and I don't see it myself, there is an
enblend --wrap option to deal with the case of a 360° panorama that
tiles horizontally, Hugin automatically sets this.

This sounds like a known Photoshop bug: if you scale an image in
Photoshop with an alpha channel, the edge pixels darken. The
workaround is to flatten the image before working on it.

--
Bruno