How to auto-crop result panorama image

[pstein]

Sometimes PTGui (v8.02) creates a panorama image where large parts are
simple black background.
The software could automatically (!) crop this images (withut loss of
picture info).

How can I tell PTGui to do it?

Peter

[PTGui Support]

This is currently not possible; the 'fit panorama' crops to the outer
edges of the panorama. Being able to crop to the inner edges is already
on the wish list.

Joost

[Keith Martin]

>Being able to crop to the inner edges is already
>on the wish list.

Is this when stitching with just some images enabled? When I do this
it is so I can patch something into a complete equirect, and because
it is generated as a full height/width image I can simply shift-drag
the image into the full one in Photoshop and it fits perfectly, no
nudging required. I can see the benefits of cropping, but I'd like to
retain the option to not crop if this ability is added.

k

[luca vascon]

FULLY agree with keith.

2009/2/24 Keith Martin <ke...@vortex.co.uk>:

>
>>Being able to crop to the inner edges is already
>>on the wish list.
>

[PTGui Support]

I think there's a misunderstanding here, probably from my part.. What I
meant is:

The Fit Panorama function automatically crops to the outer edges of the
panorama. Since the edges of the warped images are usually curved or
slanted, this results in some transparent space in the corner. i.e. an
'outer crop'.

Often you would crop the panorama some more by hand until you don't see
the transparent areas anymore and the entire canvas is filled by the
panorama. I would call this an 'inner crop'. Some users have requested
that PTGui be able do this automatically. This would be just a new
feature, not affecting the current behaviour.

You can already crop manually in any way you want by dragging a yellow
marker from the edges in the panorama editor.

And this is not to be confused with cropped layers: internally PTGui
uses cropped layers so that it only will render the part of each layer
that is actually covered by image content, improving stitching speed and
reducing memory usage. This happens automatically, you won't notice it
in the layered output.

Does this answer the questions?

Joost

[John Houghton]

On Feb 24, 10:36 am, PTGui Support <supp...@ptgui.com> wrote:

> The Fit Panorama function automatically crops to the outer edges
> of the panorama.

This is slightly misleading. It generally crops to only 2 of the
outer edges when the panorama image is not exactly symmetrically
positioned about the centre point of the output area. After
levelling, the image can be considerably offset from the centre, both
horizontally and vertically, leading to large blank areas after the
"fit".

John

[Tom Sharpless]

Hi Joost,

I would like to add something related to John's comment to the wish
list. I am one of what I'm sure is a very tiny minority of digital
panographers who sometimes use a rotating slit-scan camera. When the
lens axis points at the horizon, that generates a cylindrical pano, or
a roughly eqirectangular one with a fisheye lens, that you can load
into PTGui and correct, reformat, etc. But if you tilt the lens up
or down you get a panorama that PTGui (or any other PT-derived tool)
cannot process correctly because the center of projection no longer
coincides with the horizon, but follows some other parallel on the
panosphere. This situation requires one additional lens parameter,
call it the altitude angle, and of course code that can deal with the
conical projection in the quasi-cylindrical (rectilinear lens) case.

The quasi-equirectangular (fisheye) case is simpler. With a perfect
equal-angle fisheye, or after correcting lens errors, the lens
inclination is just a constant in the Y coordinate of an
equirectangular image, or to put it another way, the horizon is not in
the center of the image. But the only way you can get a PT-family
tool to handle that image is by padding it until the horizon is in the
middle (that is so for PanoTools and Hugin, I'm only guessing that
PTGui is the same).

So my wish is not at all difficult to implement: please make it
possible to designate the position of the horizon in an input
equirectangular image. I don't much care if you display it cropped or
not, just line it up right.

Regards, Tom

[Ken Warner]

I think that's a useful idea too. I can think of situations where
I might not want to shoot a partial spherical image. Partial in that
it has less than a 180 VFOV and not centered on the 0'th parallel.

[Ken Warner]

Oh crap, I meant I might want to shoot...

[John Houghton]

On Mar 1, 6:09 am, Tom Sharpless <TKSharpl...@gmail.com> wrote:
> to put it another way, the horizon is not in the center of the image.
> But the only way you can get a PT-family tool to handle that image is

> by padding it until the horizon is in the middle.

Tom, You should be able to adjust the horizon position using the
vertical shift parameter (lens parameter "e"). Does that work for
your images?

John

[Ken Warner]

How does (e) interact with the numerical transform in the Panorama Editor?

[John Houghton]

On Mar 1, 8:30 am, Ken Warner <kwarner...@verizon.net> wrote:
> How does (e) interact with the numerical transform in the Panorama Editor?
>

I don't think it does interact. The numerical transform will operate
on whatever view you happen to be seeing in the Panorama Editor
window.

John

[Erik Krause]

Ken Warner wrote:

> How does (e) interact with the numerical transform in the Panorama Editor?

e shifts the center for other lens corrections in the input image(s).
Numerical transform applies on the created panorama (which consists of
the corrected and warped input images) and has nothing to do with the
input lens correction.

--
Erik Krause
http://www.erik-krause.de

[Ken Warner]

Thanks Erik, John, I understand now...