[ptx] Enblend 1.0

[Morten A. Steien]

On Mon, 29 Mar 2004 15:14:24 -0800 (PST), <ptx-bounces at email-lists.org> 
wrote:

> On Mon, 29 Mar 2004, alexandre jenny wrote:
>
>> You made a great tool with enblend. It works great in many case ... But
>> not all.  I uploaded here a result of a enblended panorama which shows a
>> strange mis-interpolation line http://www.le-geo.com/temp/emblend1.jpg
>> You can see that it breaks by a vertical line the luminosity of a single
>> picture in that panorama.  I can provide you the inputs pictures if you
>> need it for debug.
>
> I noticed problems like that a couple times during development. It seems
> that occasionally the greedy assembly heuristic will make bad choices as
> to which images to blend next. If it picks an image with a long, skinny
> overlap region, there will not be enough space to use very many pyramid
> levels. Then there will almost always be a line in the result. Then in 
> the
> next blending step, it will think that the line is really supposed to be
> there, and will blend future images against the line. Therefore the line
> will never totally go away. In cases like this the right thing to do is 
> to
> blend the images in a different order. Save the image with small overlap
> for later, when there might be a bigger overlap region to use.
>
> Another option would be to force it to use a specified number of blend
> levels no matter the size of the overlap region. Then enblend will use
> extrapolation to guess what happens off the edge of each image. But this
> can go wrong too. I've seen an example where parts of the image start to
> turn gray - I think this is because the blending zone exceeds the overlap
> zone too much.
>
> So there should be a better way to automatically decide what image(s) to
> blend in next. For now you might try using the -s flag to specify an 
> order
> manually and see if you can get that line to go away.
>
> Andrew

I have the same problem with a panorama consisting of 7 images in one 
horisontal
line. I tried feeding them to enblend in reverse order and that moved the 
anomaly
to a different spot.
When I use -s i just get more anomalies in the resulting file.
I will be happy to provide the source images and the ptgui project file to 
help
debugging if needed.

-- 
Best regards,
Morten A. Steien
Hydro IS Partner