Fixing broken lines between adjacent images
ricepixels
Do you have any advice on how to fix broken lines between images? I'm
pretty certain of my nodal settings when shooting and stitching is
usually fine. But I will sometimes get broken lines from telephone/
power lines that cross from one image to another in the exported pano.
I see the "Control Point Type: New line t3" is an option but where to
place the control points on a line without any features? Whenever I
try this method it increases my Maximum Control Point Distance
greatly. I may be doing it wrong and hoping you can set me straight
(no pun intended:)
Thanks
John Houghton
common for them to exhibit stitching errors. Usually it'a not
practical to correct them with line control points, for the wires
shouldn't align because they are moving between shots. They are best
corrected in Photoshop.
When appropriate, t3, t4 ... points can be assigned on features that
are straight in the output image. Just spread them along the feature.
Use t3 points on the first straight line feature, t4 on the next, and
so on. The optimizer will try to align the points on each feature in
straight lines. However, PTGui's own optimizer does not support them,
so you need to use PTOptimizer.
John
Erik Krause
> But I will sometimes get broken lines from telephone/
> power lines that cross from one image to another in the exported pano.
> I see the "Control Point Type: New line t3" is an option but where to
> place the control points on a line without any features?
You should know that the lines you set straight line control points on
must be straight in the output panorama. If this is the case, you must
set two pairs of points, simply on the line. See
http://wiki.panotools.org/Straight_line_control_points and
http://wiki.panotools.org/Panotools_internals#Line_control_points for
details.
In any case PTGui optimizer ignores straight line control points. You
must use Panotools optimizer if you want any effect.
--
Erik Krause
http://www.erik-krause.de
Ken Warner
and the like directly. Sometimes (and emphasis is on
infrequently) you can diminish the gap by finding better
control points between the two images deleting others CP's
and re-optimizing. And sometimes a better stitch is
gotten while the Maximum Control Point Distance increases.
At least that's been my experience.
ricepixels
I should add some more information for your prognosis:
Erik: Yes, I am optimizing with Panotools but outputting with PTGui.
John: I also get the broken lines on stationary objects such as beams
or bars that start in one shot and end in the next.
Ken: Me too, I've accepted large CP distance and crossed my fingers
and corrected my broken lines better but found it created problems
elsewhere.
Thanks for bearing with me. I just discovered the New line t3 tool. I
think I understand from reading the Help and Wiki that the New line
tool is more for correcting lens distortion on things that in reality
are straight such as the base of a wall or lines in a ceiling and not
so much for reconnecting broken lines? When using this tool, do I do
it with two adjacent images like normal CP's or on the same image like
I would when correcting Vertical and Horizontal lines?
Thanks again
Michael Crane
...
On 28 Feb 2010, at 17:15, ricepixels <ricep...@gmail.com> wrote:
> Thanks gentlemen,
> I should add some more information for your prognosis:
>
If you are consistently getting many errors then probably your set up
and the lens parameters are incorrect.
Make a very friendly panorama with lots of obvious available control
points.
Work on that to make it as good as possible then save the project as a
template and apply it to future panoramas using that lens.
regards
Mick
ricepixels
I'm pretty confident of my setup. Usually it's stitching fine with a
little post-production in PS because I work with scenes with moving
people. It's just those occasional power lines, or other straight line
or two that span two images that break. Your template suggestion is
definitely on my list of things to learn next. That's for using the
exact same lens and body each time?
best regards
On Feb 28, 9:29 am, Michael Crane <mick.cr...@gmail.com> wrote:
> ...
>
michael crane
> Thanks Mick,
> I'm pretty confident of my setup. Usually it's stitching fine with a
> little post-production in PS because I work with scenes with moving
> people. It's just those occasional power lines, or other straight line
> or two that span two images that break. Your template suggestion is
> definitely on my list of things to learn next. That's for using the
> exact same lens and body each time?
yes. you can also save the lens separately and apply the lens alone if
I remember correctly.
regrads
mmick
Erik Krause
[t3 control points]
> When using this tool, do I do
> it with two adjacent images like normal CP's or on the same image like
> I would when correcting Vertical and Horizontal lines?
If you want to fix stitching errors you must use it on the two images
that don't stitch. Always place one point right and one left. The nearer
the points are on the line the less it is important that the line is
straight in output.
Notice that this doesn't actually fix the broken line but helps to find
lens and positional parameters for a better fit of the complete images.
Moreover it might affect the lens parameters of all images if you
allowed to optimize them.
It still might be your setup causing the errors. For other subjects the
blender might hide the misalignments. This is not possible for lines
crossing the overlap region. If they don't fit they must be broken
somewhere, even with the best blender available.
I'd dare to say that a lens perfectly rotated and tilted around the
no-parallax-point and perfectly calibrated won't cause any stitching
errors in non-moving subjects.
In most cases fixing in photoshop is the only possibility (select one
part of the line, copy and paste in a new layer, use transformation
tools to skew it into position, merge layer down, retouch remnants with
the clone stamp).