Am 14.03.21 um 12:04 schrieb Harry van der Wolf:
Op za 13 mrt. 2021 om 17:20 schreef 'Kay F. Jahnke' via hugin and other
I also used the new --snapshot_threads and set it to 3.
However, pv still uses all 4 cores/threads and when I "time" the command
it is exactly the same as without this parameter.
Sorry, that was a quick shot: batch jobs always set the number of
threads to the number of cores, the option --snapshot_threads only
affects the number of threads used when the job is launched via the UI
with 'U' or 'Shift+U'. I'll change it so that the option is honoured always.
I don't look at the
masks in the PTO yet, but you should now be able to simply feed images
with unwanted content 'erased' to transparency (should even be best
with
a feathered brush on the erase tool), and as long as the other images
provide content, the 'ghosts' should become invisible, thanks to the
B&A
magic.
I do not entirely understand what you mean. Do you mean I should erase
some unwanted part in one of my bracketed??images? or does pv that? Or do
you have to do that in the live view?
Let me explain in detail.
Sometimes you have things in your images you don't want to see in the
final output. In a stitching/image fusion context these unwanted bits
are often called 'ghosts', and the process of suppressing them so that
they aren't visible is called 'deghosting'. For stitching, this is often
done automatically, and a commonly used method is 'Khan deghosting',
used e.g. by hugin, see
http://hugin.sourceforge.net/docs/html/namespacedeghosting.html
pv does not have automatic deghosting (yet), so if an image of the set
you are fusing/stitching has unwanted bits, you must mask it out 'manually'.
In hugin, you can assign an 'exclusion mask', which results in the
partial image, rendered by nona, coming out transparent where the mask
is set. But pv does not process hugin's mask information (yet), so if
you want parts masked out for processing with pv, you have to 'manually'
make the unwanted bits transparent. You can do that e.g. with gimp: add
an alpha channel to your image if it doesn't have one yet, then pick the
'eraser' tool and select a *soft* brush to 'erase' the unwanted bits
with a bit of 'feathering'. Store the image. If pv reads such an image
(it must be run in alpha mode, so use pv --alpha=yes) it will exclude
the transparent parts - but not totally, instead it will honour the
feathering.
This is really interesting. I personally like sunrises and sunsets. You
mostly need bracketed sets to get a good dynamic range.
They sometimes contain unwanted parts or enfuse (up til now my used
program) does not pick the??part I want. I sometimes fall back on hugin
for its use of masks. (enfuse does understand masks, but I do have to
create them in hugin so I can just as well finish in hugin)
You're right, enfuse does understand masks, in fact I think enfuse
expects all it's input to come with an alpha channel. How you create the
transparency - hugin mask, then nona - or e.g. the gimp using an eraser
- is irrelevant. But enfuse has a limitation (to my knowledge, please
doublecheck): it's either-or for enfuse: if there is the slightest bit
of transparency in an pixel in an incoming image, it will completely
exclude the pixel. And hugin also has a limitation: the masks are
either/or as well: inside the mask is totally transparent, outside
totally opaque.
pv, on the other hand, will accept both images with alpha channel and
images without alpha channel. And if there is an alpha channel, it will
make an attempt at correct alpha blending, so you can fade stuff out (a
process called feathering or mask feathering), rather than having a
sharp discontinuity from totally opaque to totally ignored. This should
result in better output, because discontinuities are usually bad,
especially in large-scale gradients like the blue sky, where
discontinuities are very noticeable.
Because pv uses (hopefully) correct alpha blending, the results should
be very good, and masked-out bits should be even less apparent than with
other techniques. This is where I'd like feedback, just to see if my
hopes to have implemented a higher-quality image blending method are
justified. It should even be quite possible to do more interesting
things with the alpha channel than just erasing unwanted bits - in pv,
the quality masks for the B&A image splining algorithm are *weighted*
with the alpha channel, so you might put whatever content you want into
the alpha channel to make things appear 'less strongly' where the alpha
channel is 'less opaque'. This should open up a whole new set of
possibilities, but we can discuss this some other time.
So: Do you have such images (with pto) as example??that??shows??this
functionality?
Sorry, not just right at hand, but I think you get my drift. If I find
the time, maybe I can come up with an example, please bear with me.
Kay
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