Creating Simple Panoramas: getting started
When in Sydney, one of my favourite walks takes me from Berowra railway
station down to Waratah bay. I don't think that a single picture can
do justice to the scene, so I took five pictures and created the above
panorama from them. Here's how.
Many have tried to create panoramas by loading pictures into layers,
shifting them around and trying to blend the edges; this takes a long
time and results can be poor.
There are many stitching programmes available, I use
which is available (free of course) on
Linux, Mac and Microsoft operating systems - just go the the download
page. However I expect that the principles are the same for commercial
programs. Enblend, available from the Hugin page, does a very nice job
of blending the images, so download that as well.
- The individual pictures will form a whole, so camera settings should
be the same for each picture: put everything, focus, aperture, shutter
speed and white balance on manual and leave unchanged for every
picture. Take a note of the focal length.
- Each picture must overlap the adjacent pictures by at least
25%. Using a tripod helps but is not necessary.
- Try to avoid objects moving across picture boundaries.
- Taking jpegs will do, but in this case the pictures were in
Canon raw format and converted to 16bit tiffs using
using the same setting for each picture.
- Run hugin. This will bring up the Images screen. Use the
Add individual images button to load the images; make
sure the first is the leftmost and the rest are in order.
- Use the tab at the top to access the Camera and Lens
screen. Click on the first image and enter the focal length in the
first box (this is 35mm equivalent, so I enter 28, not 7.2 as I
used the wide-angle end of the zoom). Tick the Inherit box
to save doing this for each image. Check that the Degrees
of view makes sense - it is about 63 degrees for me.
- Hugin needs to know the centre and horizon of the panorama.
Return to the Images screen. Click on the centre image and
click Anchor this image for position and Anchor
this image for exposure. Click on set anchor image, a window
pops up of which Fig. 1 is a part. Click to set the
cross as shown; the critical thing here is to set the horizon
correctly to avoid a banana-shaped panorama. In
Fig. 1, I have chosen the far beach as the horizon.
- Click on the Control Points tab to bring up that
screen. There are two identical pictures (Image 0, the left-most
picture) side-by side. Click on the 1 above the right-hand image;
you now have the first two pictures side by side.
- Figure 2 shows four pairs of control
points, that is points in the two pictures which are the same.
It is important that the points that you choose cannot move; for
example: don't choose the boat or a cloud. Points are selected by
first clicking on the left-hand picture followed by a click on the
right-hand picture at about the same place. Hugin automatically
fine-tunes the second point to match the first accurately; if this
doesn't work, choose a more salient point. Four points is about
right for this sort of picture. Hugin will choose points
automatically, but this is not recommended as it might choose the
boat or a cloud. Repeat for the other pairs.
- Click on the Optimiser tab. Click on the
Optimise now! button and wait a few second for Hugin to
complete its optimisation. Towards the left of the upper toolbar is
a screen icon representing Panorama preview; click on this
and a new window appears. In the new window, click on
Update and you should see Figure 3. This
is how hugin proposes to stitch the panorama. Notice how it
distorts the images to give the correct perspective. At this point,
I often return and readjust the Set Anchor Image screen
and repeat the optimisation (leave the control points alone).
- Choose the Stitcher tab to access that screen. Choose:
Equirectangular, nona and tiff in the
various options. Tick the soft blending box, this removes
the any visible joins which appear Figure 3. Choose
the pixel size of the panorama, the ``optimal'' size is usually far
to big. I chose 8000 pixels horizontally. Finally, click the
Stitch now! button. Go and have a cup of tea as this will
take a while.
You should now have a tiff corresponding to the panorama previewed in
Fig. 3 but at a higher resolution and with nicely
blended boundaries. Read this into your favourite program (I use
Gimp, but PS is fine) and crop off the rough edges. I was left with
the problem that the boat had moved from the first to the second
picture giving me one and a half boats in the final picture - clone
tool to the rescue.
As well as printing, the panoramas can be
A lot of relevant information is gathered at the PanoTools
Creating Simple Panoramas: getting started
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