Edit zenith and nadir in one go with PTGui

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Here I show you a fast way to retouch zenith and nadir in one go.
Use this method only if you have a proper stitched panorama and only
the top (zenith) and bottom (nadir) areas need some retouching.
Otherwise use other technics as described under
Extracting and inserting rectilinear Views and How to use PTEditor.


Remap to zenith and nadir view

Open PTGui and add one spherical panorama. As you can see the source pano is 6000 x 3000 pixels in size:

PTGUIret 001.jpg

On the Lens Setting tab add the yellow highlighted values:

PTGUIret 002.jpg

On the Panorama Settings tab add the yellow highlighted values: "Use fast transform" has now moved to "Create Panorama" tab.

PTGUIret 003.jpg

On the Image parameters tab add the yellow highlighted values and you can immediately see the remapping of the image:

PTGUIret 004.jpg

Enable Lock width and height, press Set optimum size button, choose Maximum size and compare the values with the original size of the panorama. "Lock width and height" was called "Lock aspect ratio" in older versions.
Choose as output file format TIFF (.tif) for fewer quality loss. Press Create Panorama to start the remapping process:

PTGUIret 005.jpg

You don't have to add control points and optimize in this case, so press OK.

PTGUIret 006.jpg

Retouching zenith and nadir in one go

Here you see the remapped panorama opened in Photoshop. The yellow circles mark zenith and nadir as nearly flat regions.
It is now much easier to retouch these regions.

PTGUIret 008.jpg

Remapping back to normal view

Open the retouched panorama again in PTGui with the same values under Lens Settings and Panorama Settings.
Fill in the yellow highlighted values under Yaw and Roll.
The Warped view changes imediately to the original projection.

PTGUIret 010.jpg

Change the values as below, alter output file name to your needs and press Create Panorama!

PTGUIret 011.jpg
If you want the best possible quality, follow the next steps. Otherwise you are done here.

Merging with most quality

Open the retouched, spherical pano in Photoshop and take a look at the layer palette.
Drag and drop the background layer over the new layer icon to make a copy of it:

PTGUIret 012.jpg

Here you can see an additional layer as copy of the background.
Now drag and drop background layer over the recycle bin icon at the bottom of the
layer palette to delete it:

PTGUIret 013.jpg

Rename the existing layer to zenith and nadir by double clicking its layer name:

PTGUIret 014.jpg

Choose the Marquee Tool and change the feather width to 40:

PTGUIret 015.jpg

Set the grid under Edit > Preferences > Guides, Grids & Slices > Gridline every to 50%
and Subdivison to 1. Left click the grid cross in the middle of the pano and drag the selection
square to the most right side by holding Alt key until it looks like the image below and then release the left
mouse button:

PTGUIret 016.jpg

Press Delete key that only zenith and nadir region of the retouched pano will stay:

PTGUIret 017.jpg
To delete the rectangle selection, press Ctrl+D.

Open the original pano. Switch to the retouched pano and press Ctrl+A to select the whole image.
Change to Move Tool and drag and drop the retouched pano over the original
pano by holding Shift key to align it proper.

PTGUIret 018.jpg

Now you can see two layers in the original file, the original background layer and
on top of that, the dropped layer.

PTGUIret 019.jpg

Flatten these layers to background under Layer > Flatten Image :

PTGUIret 020.jpg

You are done now, but don't forget to save the panorama with a different name:

PTGUIret 021.jpg

Peter Nyfeler (Pitdavos)