Vertical Panorama Problems
Tim
upgraded PTGUI to the latest 8.3.6 version and have been having
problems I have not seen before. My panoramas are all of landscapes.
My horizontal panoramas are behaving just as they should but my
vertical ones are showing rather peculiar traits.
The overall stitching seems fine but there are patches in the finished
image that are soft and "woolly" despite the program reporting back to
me that the control point accuracy is "very good". The biggest
problem, however, is that the exposure blending is odd. there are
patches that are more sharp, more saturated, more contrasty etc etc
and then there are patches that are misty, slightly greyed. the
divisions between these areas seem to be on diagonals. It is almost as
if the image is made, in areas, in loosely triangular pieces. The
vertical panoramas are usually comprised of 4 or five images ranging
from shots of the ground plane up to shots which are mostly sky. There
is often quite a range of exposure between the shots of the darker
ground and the lighter sky. The problems appear more commonly where
there is the greatest exposure difference between pairs.
I have not had this problem before, the program has been able to
handle the blending very efficiently and I wonder if something has
gone wrong in the latest version.
I am using Windows XPpro SP3
Roger D. Williams
attempt by PTgui to blend images that are affected by wind,
like rippling grass or tree leaves.
If you output with layers, a little judicious selection of
one layer over another will give you "unrippled" grass.
Playing with precedence settings can also reduce this. A
lower precedence for one layer will allow the other to
predominate without attempting to blend then.
It may not be the whole answer, but it's worth looking into.
That this comes where the exposure difference is greatest
is a pointer in the same direction, but also may make it
difficult to select one layer over another unless the
underlying brightness levels are similar in the region
affected.
Roger W.
--
Business: www.adex-japan.com
Pleasure: www.usefilm.com/member/roger
John Houghton
all the images the same exposure with the camera in manual mode. If
your subject has extreme brightness range, take multiple sets of
photos with different exposures using the auto exposure bracketing
feature on your camera, if it has one, and merge the sets with fusion/
HDR techniques or manual blending in Photoshop. Another option with
your present images would be to try blending with Enblend and
Smartblend.
John
Tim
Roger, I didn't quite understand your reference to "precedence
settings". I experimented with some gradient masks for the various
layers of the panorama in Photoshop and did solve some of the blurry
areas -- in essence setting precedence for the images that were
clearer in some areas. What I also did was process the raw (CR2)
images in Photoshop rather than bring them into PTGUI as raw files. I
was able to make the exposures more similar and PTGui was able to
handle them better. But the problem is that with a vertical panorama
that moves from groundplane to sky one is likely to get exposure
variations and part of the reason for taking the shot as a panorama is
to be able to use different exposure settings to accomodate the
different light values. To use a single exposure setting somewhat
defeats the purpose. I have in the past bracketed exposures and tried
the HDR techniques that you suggested, John. Quite successfully as
well, largely using the program Photomatix. In the case of these
panoramas that haven't worked so well, I did not have a tripod and in
this context it seems that bracketed photos should be made using a
tripod. Another thing I could try would be to process the raw images
as if into a bracketed series. However, I was not aware of the plugins
you mentioned, John. I have now been using Smartblend on the same
troublesome images and it has worked extremely well. I thank you for
the suggestion.
I could not get Enblend to work. I kept getting an error message:
enblend cannot load images (placed in my docs/local settings/temp
folder) ptg_2472_AGVM3G.tif. because the Enblend format of the fikle
is unrecognized or unknown.
When I looked in the folder there was no such item, not anything like
it, so I suspect that PTGUI is not interacting with Enblend properly
(or the other way round)
Many thanks
Tim
> > I am using Windows XPpro SP3- Hide quoted text -
>
> - Show quoted text -
Roger D. Williams
On Fri, 29 Jan 2010 10:00:26 +0900, Tim <ti...@netaxs.com> wrote:
> Thank you, Roger and John for your responses.
> Roger, I didn't quite understand your reference to "precedence
> settings".
I should have said "priority settings" (sorry). If you are not familiar
with these they are certainly worth exploring. You will find them after
you select "Advanced" settings, then "Image Parameters" and scroll right
until you see "Priority Settings." The default setting is 100 (%). If
there is something in one image that you would like to de-emphasize,
just reduce the setting. Dropping it to 25% will create a noticeable
difference, and even setting it to 5% will still let PTgui use it for
bits of the panorama that are only available within it. It will just
reduce the area of that particular shot that overlaps with the
adjacent one and is blended with it.
I found HDR too much trouble in terms of ghosts and their removal, and
now use "pseudo" HDR as provided by PTgui's "Exposure fusion" which
oddly enough works on a single set of exposures. It is considerably
more flexible and effective than relying on PTgui to do its best with
automatic exposures, although I admit the latter can also do a very
good job in some circumstances.
Roger W.
John Houghton
> in the case of these
> panoramas that haven't worked so well, I did not have a tripod and in
> this context it seems that bracketed photos should be made using a
> tripod.
For handheld shots, I would align one exposure set for the base
panorama, and then use control points to align individual images of
the other sets to the corresponding images of the aligned base set.
i.e. don't use the link facility to force images to share common y,p,r
values, which isn't appropriate. That generally works quite well.
John