The Making of a QuickTime VR Panorama
For the amateur photographer interested in creating QuickTime VR panoramas, here is
a summary of steps that I've found work for me. I have no doubt that better
tools and equipment would produce better results, but it is possible to construct
panoramas of acceptable quality quite inexpensively.
Minimum Requirements
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As good a camera as you have— a manual SLR is better but
even a cheap automatic will work.
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A good computer with about 50 MB of disk space.
I use an Apple Macintosh G3 (beige).
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Some version of Adobe Photoshop— I really can't imagine
doing this without it.
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Apple's QuickTime (you probably need the registered ‘pro’
version if you want to put your panoramas on the Web) and the
‘Make QTVR Panorama’ tool.
Photograph
Everything begins with the sequence of photographs. Here is a list of things
to watch for— probably none of these are critical, but the better you can
make your pictures, the more time you will save yourself later on:
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Use a flat, stable surface, or a tripod that you can rotate the camera
on, so that the horizon will line up from beginning to end.
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Make sure the pictures overlap somewhat on the edges— about one-fifth
seems to be fine. The amount of overlap doesn't need to be consistent.
I've used between nine and thirteen exposures for my panoramas.
-
It helps to shoot so that objects at the extreme pitch angles are distant
and near objects are around the horizontal center. The stitching later on
needs to transform the spherical projection of the camera to a cylindrical
projection of the panorama. Because I don't know of any tools that do
this automatically, you otherwise end up doing a bit of manual work later.
Unfortunately in practice, although the upper edge usually is distant (sky),
the lower edge is often not.
-
It also really helps to use a good camera that introduces as few distortions
as possible. The automatic cameras determine shutter time and f-stop
differently for each exposure, causing more work to balance them back out
later on. Also, the cheap plastic lenses of these cameras introduce
horrible circular brightness distortions. Even my old manual Praktica
MTL5B made much better pictures.
-
I imagine that you should get more consistent contrast and color balance
if you take the pictures when the lighting is overhead (i.e., midday if
you are outside).
Digitize
The key here is to try and minimize the number of processing steps, because the
further along the chain you get the more quality you lose and the less consistent
the frames become. If you use a digital camera, this step is no problem. With
a film camera, there are four different ways that I know of to convert photographs
into digital images:
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Develop the film and use a negative scanner. I haven't tried this,
but I imagine it should give very good results.
-
Develop the film and process into a Kodak PhotoCD. This will leave you
with a disc with high-quality uncompressed pixel map (lossless) images
of various sizes (my guess is that Kodak uses a film negative scanner).
Unfortunately it is rather expensive: 1 da$ for the
disc itself plus about 1 $ per exposure. If you take this approach, you
might want to use a short film and make only the minimum number of
exposures necessary to save on processing costs.
-
Develop the film and process into a Kodak PictureCD. This is similar
to the previous option, except that the images are noticeably lower quality
and they are compressed to JPEG on the CD. My guess is that they scan
the prints because you cannot get the PictureCD without them, and you
can see dust and hair artifacts on the scans. Also, the contrast and
color are different on each exposure, presumably because of the processing,
so you will have to do more work later on to correct for this. The disc
and prints together cost only about 1 da$.
-
Develop and print as usual and scan. This is probably the cheapest option,
but is going to be more work. You will want to take care to minimize the
contrast and color corrections normally performed by the scanner to give
the most consistent results.
Stitch
Once the photographs are digitized comes the hard part: stitching the individual
pictures into a consistent linear panorama. First, combine the photographs into
a single Photoshop document, each single photograph into its own layer:
Then, line up the pictures so that the features match as well as possible, though
they will often not, especially when objects are near.
If the brightness and contrast of individual photographs are not balanced,
you need to even them out. I haven't found an easy way to do this:
-
Select an area with its border about midway the gradient of the
brightness distortion.
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Feather the selection with a radius about equal to half the length of
the gradient.
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Invert the selection so that it now contains the part of the image
to be corrected.
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Use Adjust Brightness/Contrast to even out the brightness distortion.
In addition to this, to account for processing differences in individual photographs
you need to adjust the brightness, contrast, and color balance of the frame in its
entirety so that each frame matches its neighbor.
You can see that the result of all this is better, though not perfect:
Finally, use the Perspective and Distort effects around the left and right edges
of each frame to line up the features (note how the horizon has become much more
even):
Finally, flatten the image into a single layer, rotate 90° counterclockwise
and save as an uncompressed PICT. The image width and height need to be
a multiple of some numbers that I always forget, but you can go on to the next step,
let the tool suggest the right image size for you, and then come back and crop it.
Movie
You need Apple's ‘Make QTVR Panorama’ tool to create the panoramic
movie. Remarkably, it is the simplest step of all, and there is not much to do
here but select the compression method— I use medium Photo-JPEG.
If you intend to serve the panorama on the Web, you need ‘flatten’
it into a single fork. You can do this easily by opening the panorama movie in
the QuickTime Player and then Exporting it as a ‘hinted’ movie.
Note: A “da$” (or ‘decadollar’) by the
Système International (SI) system of units, is 10 dollars.
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Ben Hekster