I just started a panoramic project involving 275 8GP full-size tiff
images split across 25 stacks. The images amount to around 14GB. Since
this is the first time I've used Hugin, I thought I'd document what I
found confusing (correct my workflow) or broken (correct hugin):
Major Major Major Problem:
Even though there are 275 images, they are split across 24 stacks, so
not that many control points are needed. Finding the control points
takes about 45 minutes using multirow CPFind + align_image_stack and
generates approximately 30.000 points. The points match the adjacent
bracketed images, and one optimally exposed image from each stack
matches the adjacent stacks. The matches are generally very good and I
am able to reduce my error distance for all points to less than 2.5px
relatively quickly.
However when I save and restart, while there are maybe the same amount
of control points according to the control points table - around
30.000, I don't remember the exact number, they match different
images. So obviously the matches are now very bad. For example,
adjacent bracketed images are generally no longer matched (missing all
control points). Adjacent stacks are also generally no longer matched
(missing all control points), and if there are matches, they are weak.
My maximum CP distance jumped from 2.5 to 30, and average distance
from 0.09 to 8. After re-optimization, maximum distance jumped up to
50, standard deviation back down to 2.125... but the image alignment
was completely screwed up. Points I'm pretty sure that I deleted by
hand have re-appeared. It is an enormous mess. (note: and I haven't
even used the fast preview window -> see my last question)
Luckily, Hugin saves the individual image positions correctly so if I
don't apply optimizations I don't modify the panorama. However, I just
found an area that needs more control points to get rid of some
glitches, and the only way to modify the control points and
re-optimize is to start from scratch.
Other Problems:
This means I can't close/reopen hugin, which is annoying not only
because I've had hugin crash twice, but also the "clean control
points" freezes hugin and I have to manually kill it. Ten hours after
clicking "clean control points", the hugin interface remained
inactive/dead. The terminal outputs a lot of:
" ...
" Number of images 2
" No Parameters to optimize
" Bad params
" ...
Really Minor Problems:
. Hugin segfaults if I press enter on the keyboard while the splash
window has focus
. If there are too many images in the horizontal list of the preview
tab of the Fast Preview Window, then a scrollbar appears and partially
covers the image list.
. stacks only works out-of-the box with a maximum of 12 stacks. Images
from any extra stacks remained unclicked in the optimizer/exposer tab
lists, and so aren't aligned/optimized.
Stuff I just don't understand:
Two images from adjacent stacks have about 40 control points with a
maximum distance of 2px. To the eye, the points looked perfectly
aligned. However, Hugin decided to rotate the right image 180 degrees.
Basically, the first four stacks were right-side up, the next four
where upside-down, the next two where 90 degrees clockwise, etc
despite perfect control point matches. I had to go to the image tab
and reset the roll and pitch manually.
Feature Requests:
. The control point table - 30.000 points - just too slow. Several
minutes required to regenerate the list after deleting a point. Can it
be made faster?
. Similarly, the layout tab of the fast preview window is even slower
- several tens of minutes to update.
I find that the layout mode of the fast preview window is
indispensable. If it can't be used and the user knows the approximate
angle of rotation between bracket sets, there should be a method in
the images tab to programmatically set the yaw, or pitch/roll: for
example progressively rotate each stack X degrees counterclockwise
(from above)
Questions:
. Is there any tool that can merge stacks into HDR without any
alignment or other pre-processing? That way, I can work with only 24
hdr images instead of the full 275? And can exposure fusion work with
HDR images?
. Is it possible to configure control point creations on:
* all images
* only overlapping images
. Does changing the EV of "displayed images" in the fast preview
window have any effect on the output panorama, especially when using
HDR or Exposure Fusion modes.
. Why does hugin's stitching/enblend use practically no memory (25% of
RAM) but all swap space (100% of partition)?
. Is it possible to run the *same* vertical line across several
images? == four points across two images that also help precisely
align the images.
. I assume that the fast preview window tools (center/fit/straighten)
actually affect the image parameters (yaw,pitch,roll,etc) and do not
modify control points. Therefore, after applying center/fit/straighten
I would think if I subsequently optimize the project it would revert
to the exact state before applying center/fit/straighten. That is, the
image positions/parameters are identical to before applying
center/fit/straighten, and the control points and control-point
distances are also identical to the state before applying
center/fit/straighten. Why is this not the case?
Anyway, aside from these several questions, the documentation is very
good. And I really like the interface.
thanks
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