Table of contents
Preparation
PTGui and Autopano
Fine-tuning with PTGui
The zenith-image
Assembling the images
Creating the QTVR

Go here if you look for an updated tutorial for PTGui V5 and above!

Part 2: PTGui and Autopano

You have your first images on your hard disk?

OK  - to give us plenty of work to do I have chosen a real and "imperfect" set of images.  They were taken handheld and do not meet the nodal point!

If you want to, you can also use my source images (reduced quality, 3.4 MB download)

fisheye1.jpg (4873 Byte) fisheye2.jpg (4872 Byte) fisheye3.jpg (4774 Byte) fisheye4.jpg (4832 Byte) fisheye5.jpg (6172 Byte)

Fisheye lenses tend to have very recognizable light falloff on the outer parts of the image. Also chromatic aberrations are a big issue. You may want to minimize these flaws before stitching your panorama.
Here are some good resources how this can be done:
PTShift by Eric Gerds
More technical background about chromatic aberration can be found at the homepages of Jim Watters and Erik Krause.

The images show the recently renovated "Kloster- und Wallfahrtskirche der Unbeschuhten Karmeliten" in Vienna.

The first 4 images are taken in portrait mode. The 5th image is the so called zenith- or sky-image. I did not shoot a nadir- (or floor-)image because of the regular texture of the floor.

To capture the high dynamic range of the interior i have slightly under-exposed. To get the correct exposure, we have to adapt the brightness of the finished panorama.


Please start now by opening PTGui. First we will only use the first 4 images.

Load them:

ptgui01.jpg (54923 Byte)

For further processing the images, we need to rotate them to portrait mode.
A simple method is to use the "PTGui Project Wizard" with the following settings: "360 degree single row panorama", 2 steps ahead use the button "Rotate Counterclockwise". Afterwards click "cancel" to abort.
As a nice side effect we already have pre-positioned our source images, although the result looks a little quirky:

ptgui02.jpg (45129 Byte)

We will now bring that in order::

  • Go to the tab "Lens Settings".
    The Lens Type is "Circular".-> Using a recent version of PTGui you will already have this Lens Type.
    You will notice that now only the "Horizontal Field of View" can be entered. A simple and sufficient value could be 180.

    If PTGui complains about entering a value above 120 you have not installed the correctly adapted version of pano12.dll (or you may have installed it in a wrong location)

    All other settings will be left at the default values.
    ptgui03.jpg (54646 Byte)

  • Now click on the tab "Panorama Setting"
    We will need the File-Format "Multi-Image TIFF" for later use of enblend.
    Projection must be changed to "Equirectangular". This is the only type capable of projecting a full 360x180 panorama on a plane. Also adapt the field of view to full 360x180:
    ptgui04.jpg (43973 Byte)

You will notice that the "Panorama Editor" window shows the first impression of your full panorama:
ptgui05.jpg (51627 Byte)

Don't worry about the black edges. You can remove them by clicking on the "Crop"-tab.

Cropping the image is helpful for visualizing the panorama in the editor window but it is not really needed. In fact there are some disadvantages to cropping the image: The creation of the panorama will take more time and full 16bit images are silently downgraded to 8bit color depth (at least in our case, where the crop circle leaves the image boundaries).

ptgui06.jpg (55579 Byte)

With a click on the button "Apply to all images" we will transfer the crop to the rest of the images.
If you look closely you will notice that PTGui automatically adapts the field of view of your lens. This is OK - we use a guessed value which normally would be about 170-180 degrees of a 8mm fisheye on a DSLR.

Autopano:

We will now use the external tool "Autopano" to automagically create some control points for our panorama.

I hope you already have told PTGui where to find your autopano.exe. If not, please do so now (int the Menu "Options"). You can also leave some parameters for Autopano's command line there. Here are some values that work acceptably for fisheye lenses:

/size:800 /keys:30 /ransac:1 /search:1
Finding the "right" options for Autopano depends heavily on the way you take your images and the scene itself. If you want to know further details about choosing parameters you may follow the discussions at the Panotools-List where i also thankfully got some good tips for parameter combination.
In my example images you will notice a very special problem: there are quite many wrong control points. This is due the nature of the scene, having many recurring ornaments.

Now start Autopano through the Menu "Plugins"
This is now a good time to make some fresh coffe and feed the cats - you won't miss anything exiting the next minutes...

As soon as Autopano has finished you will see a message appearing on your screen:
ptgui07.jpg (6610 Byte)

 

Now advance to Part 3: Fine-tuning with PTGui