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by Max Lyons
Late last year, an image was posted on the internet which was claimed to
be the largest digital“photograph” ever. Here the photographer explains
how he did it. And what‘s more, you can download the shareware used
to create it!
T
he photo at right is a view from
Bryce Point in Bryce Canyon
National Park in Utah. Nice,
huh?
But we haven’t shown you the photo
just because of its scenic beauty. This
image is believed to be the largest
digital photograph ever. If SILICON
CHIP pages were five metres wide,
this image could be printed at high
resolution!
The original contains 40,784 x
26,800 pixels – 1,093,011,200 pixels
in total, or a little more than one gigapixel.
Now you might think that it would
be a rather impressive digital camera
to take such a photo – and you’d be
half right. In fact, such a camera hasn’t
yet been invented. This image actually
consists of 196 separate photographs
shot with a garden-variety Canon D1,
then stitched together into one seamless composite.
I have been unable to find any record
of a higher resolution photographic
(ie non-scientific) digital image that
has been created without resizing a
smaller, lower resolution image or
using an interpolated image.
Here’s another way to think about it.
Given that the resolving power of the
human eye (under ideal conditions at
the centre of the retina) is about one
arcminute (1/60th of one degree). This
image captures considerably more detail than I (or any other normal sighted
human) was able to see with my eye
when standing on the overlook at
Bryce Point. Assuming one pixel per
arcminute, an image with dimensions
of 3780 x 2485 would suffice to capture
the amount of detail that the naked eye
could resolve. This image has more
than 100 times this detail. Looking at
the full sized digital image, one is able
to see things that might have been difficult or impossible to spot, even when
using binoculars.
Below are some crops to simulate
the amount of detail that would be
captured using cameras of different
resolutions (I don’t own any of these
higher resolution cameras, so the
crops below are simulated. Due to
the resizing algorithm used to create
these crops, they may over-estimate
the amount of detail actually captured
by these cameras).
How was it created?
The first step in the creation of the
image was to choose an appropriate
subject. There were a number of technical issues that I had to consider that
are not normally encountered when
taking single images.
For example, it took me 13 minutes
simply to take all the photographs and
I was shooting as fast as my camera
could write images to its memory
card. So I needed a subject that was
relatively static.
Secondly, I knew that I would have
to use a very long focal length lens
to take the image, otherwise the final
composite would end up with an
extremely wide field of view. . . some-
RESOLUTION:
What does it mean?
Each of these simulations
shows the amount of detail
captured shooting the same
scene at different resolutions.
While they are simulations,
achieved by resizing the 1GB
image) they probably err on
the good side (actual results
would probably be worse.)
76 Silicon Chip
Unresized (1.09GB)
140 megapixel camera.
50 megapixel camera.
www.siliconchip.com.au
We obviously can’t do the image justice printed on a magazine page. In true life, it would be five metres wide . . .
thing I didn’t want. This also presented
challenges due to the extremely short
depth of field when using very long
lenses.
The second step was to assemble
the images. This was a complex and
lengthy process. My normal procedure
(using “PTAssembler” [see “About
the software”]), Panorama Tools and
Photoshop) was not sufficient in this
case for a number of reasons because
of the size and number of images I was
working with.
For example, the version of Photoshop that I use cannot work with
images with pixel dimensions of more
than 30,000. So, my solution was to
22 megapixel camera.
www.siliconchip.com.au
modify some of the existing programs
in my workflow and write a number
of new software programs to create
this image.
Why Bother?
Good question. The short answer is
“why not?” As digital camera resolutions have increased and the hardware,
techniques and software for stitching
multiple images into composites have
improved, there has been specualtion
about when gigapixel images would
become possible.
This seemed like an interesting challenge to me. (I still think that it will
be a long time before true gigapixel
11 megapixel camera.
6 megapixel camera.
cameras will become available.)
However, this isn’t the only reason.
I’ve been producing and printing
stitched images consisting of 20-150
megapixels for several years.
I’ve become addicted to the amazing detail that is visible in large prints
from these images! Gigapixel images
present the possibility of producing
some of the most amazingly detailed
prints at sizes of 10-15 feet wide. A
300ppi print of this image would
measure about 3.3m wide, while a 240
ppi print would be close to 5m wide.
Even printed at this size, the image
would appear very sharp upon close
inspection.
3 megapixel camera.
February 2004 77
Another advantage to an image this
size is the ability to crop very small
portions of this image in a number
of different ways and still produce
extremely high resolution large prints.
How do you print It?
Another good question. The short
answer to this is that there appear to
be a number of alternatives, but none
that I’ve discovered I’m completely
happy with. So, I’m still thinking about
it! However, I’m interested in hearing
from anyone who would like to partner with me on printing this image. I
think it would be an excellent match
for (and an excellent demonstration
of) large format printing technology. If
you have an idea or a proposal, please
let me know!
About the software
With time and patience, anyone can
achieve the results seen on these pages.
Basically, two programs are used:
PTAssembler and Panorama Tools.
In fact, you could use just Panorama
Tools but PTAssembler will dramatically help you.
PTAssembler is a Windows “helper”
program for Panorama Tools, Helmut
Dersch’s powerful panoramic image
stitching software.
Despite (perhaps because of) its
numerous features and capabilities,
Panorama Tools can be challenging to
use. It requires a lot of time and effort
to create the “scripts” needed by Panorama Tools to stitch multiple images
into a larger panorama. PTAssembler
is designed to make this task as easy as
possible. No knowledge of Panorama
Tools or its script syntax is needed in
order to operate PTAssembler.
I’ve been using Panorama Tools
This shows the 196 individual digital photographs before they were stitched
together to achieve the single 1 gigapixel photograph shown earlier. It took some
thirteen minutes to shoot the series, as fast as the Canon 1D camera would allow.
for a few years to create my high
resolution images and continue to be
impressed by its abilities. However,
many people (myself included) find
it extremely difficult to learn and
use. I decided to write PTAssembler
to make it easier to use Panorama
Tools. Even with a “helper” program
like PTAssembler, Panorama Tools is
complicated and requires more input
from the user to create a final panorama than many popular “automatic”
stitching programs. But the results are
worth it. With a little time, perfectly
stitched panoramas can be created
every time.
Overview of panorama
creation
Stitching images together using
Panorama Tools is a little different
from most “automatic” stitching programs.
For example, the user is required
to set “control points” on each image marking features that appear in
the overlap region between adjacent
images. Unlike automatic programs,
Panorama Tools does not know (and
will not guess) how images should be
aligned without these control points.
Another aspect of using Panorama
Tools that may seem strange to users
who are used to automatic programs
is its “optimiser”. The optimiser uses
the control points to determine the
best positioning for individual images
in the final panorama. The optimiser
also uses the control points to detect
and correct any lens distortions (e.g.
Here’s how it works, with (in this case) four overlapping photographs. digitally “stitched” together to produce one
composite picture that would defy even the experts to pick! There are several fully automatic programs around which
will do this simple task; none could possibly hope to handle a 1GB final image nor do it anywhere near as well!
78 Silicon Chip
www.siliconchip.com.au
barrel or pincushion) that can cause misalignments between images.
PTAssembler allows the user to optimise all parameters
necessary to create a panorama without having to write
and/or modify scripts.
Although Panorama Tools can output a final image in
JPEG, TIFF (and other) formats, one of its greatest strengths
is its ability to output a “layered” image file that allows
the user to perform the final blending between adjacent
images manually.
Panorama Tools takes care of warping, aligning and positioning the images so that they line up correctly. However,
you can choose to perform the final blending (i.e. decide
the exact position of the “seam” between images) in your
favorite image editor.
For a beginners guide to creating a stitched image using
PTAssembler, please refer to the on-line PTAssembler
Tutorial at www.tawbaware.com/ptasmblr_tutorial.htm
Also, complete documentation is included with PTAssembler but is also available on-line.
Where from, how much
Both Panorama Tools and PTAssembler are shareware;
that is, they can be downloaded free of charge but a small
registration fee applies. Some features may not work fully
without registration.
All necessary links for the software along with a large
amount of documentation, examples, tutorials and further
links (and much more besides!) may be accessed via the
author’s website, www.tawbaware.com
SC
About the author/photographer . . .
This is me. . .
Max Lyons. So is
the guy on my left,
and the one on his
left, and the... (not
forgetting the one
peeking in from
the edge of the
photo!)
As you can see,
I have a lot of fun
“doing things”
with digital photography.
I’m the author of the software and photographs in this
article. This isn’t my “day job” but I do spend a lot of
time at it!
I became interested in progamming and digital photography around 1996, after buying a “Teach yourself
Visual Basic” book and a fantastically over-priced
digital camera.
The programs on my website (see below) are the
product of a few years of work and far too many late
nights...
I have some other stuff on the web. There is the digital
camera software (www.tawbaware.com), and some of
my better photographs (www.tawbaware.com/maxlyons/
index.html).
If you are moved to do so, you can email me at
maxlyons<at>tawbaware.com. I promise I will read them
all but as you might imagine, I get a lot of them so I can’t
guarantee I will answer every one!
www.siliconchip.com.au
February 2004 79
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