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Presented are tips and techniques for underwater panorama
creation, adding signature lines to your panoramas, and
getting your images to de-warp correctly. Issues and
examples relating to the number of exposures required for a
panorama as well as the panorama size and quality settings
are discussed along with a multinode project run through
with examples of the results.
Nodal Point - the Optical
Center of the Lens
Before we go any further in this section, we must
understand the term "lens nodal point". This is a somewhat
confusing term which we will attempt to define by way of
physical demonstration rather than through an optics lesson
or mathematical equations.
We have been told that the camera must be positioned and
rotate over the optical center, or nodal point, of the
camera's lens. If we do not do this, our panoramas will look
like horrid and we will be witness to the end of the world
as we know it. The basic idea is to prevent image parallax
between near and far objects which will ruin an otherwise
good panorama. For an example of image parallax, perform the
following experiment: With one eye closed, hold your hand at
arms length with your thumb pointing upward. Position your
arm so that your thumb is between your eye and the vertical
portion of a door frame. If you are doing this correctly,
your thumb should be obscuring part of the door frame. Now
turn your head left and right. Notice how the door frame
becomes visible as you move your head a bit left or a bit
right? This is an example of image parallax due to the fact
that the nodal point of your eye is not over the center of
your head rotation. You can do this same experiment with a
camera and attached lens. Using a standard 35mm camera,
pivot the camera left and right over its tripod mount and
you will notice the same effect of the far image becoming
visible as you get a bit left or right of where you started.
If you pivot the camera at a certain point under the lens,
you will notice that the far image remains obscured. This
special point of rotation is called the optical center, or
nodal point, of the lens. The idea is to mount the camera on
the panhead so that the nodal point of the lens sits
directly over the rotation axis of the panhead. Now that we
have that issue out of the way, we can get into more
interesting topics.
Panoramas Without a
Tripod
You hold the camera (in portrait mode) up to eye level
with your arms tucked in against your body. The idea is to
snap pictures which overlap by about 50% (easy to guess at
while looking through the view finder) all the way around
for 360 degrees of images. By holding the camera steady, and
arms tucked against your body, the images will be fairly
consistent. You may want to lean back a little bit while in
this position to help put the camera lens above your body
rotation. You will need to do an interactive stitch, but the
results are not bad. You will probably need to crop the top
and bottom of the resulting stitched image to account for
inaccuracies while shooting the panorama.
- The following is a closeup example of the raw stitch
result showing the inaccuracies introduced when using
this technique
- Closeup
of Resulting Stitch from Hand Held Photos
-
- Amount
of image inset required to get rid of the stitching
errors
-
As an example of how well this technique works, we
pulled out some old images from a camping trip in which
we hiked a few miles looking for a place called "hell to
find lake". We found it and took overlapping photos of it
for future reference. Little did we know that a year
later we would have the technology to take these pictures
and produce this stitched image of the area. As you can
see, you do not need to create just panorama movies, you
can create super wide images as well.
- Hell
To Find Lake in Trinity National Forest
-
As a final example of shooting without a tripod, we
will show what you get if you shoot a panorama with a
mono-pod. This monopod example was taken at Disneyland
without the benefit of any panhead. This was strictly a
monopod with a camera attached. The only benefit this
method has over the hand held method is that the camera
stays at one height and pivots around a consistent
center. The overlap was a guess for 50% and the level of
the unit was total guess for each shot. We did not use
our custom compass/bubble level panning device for this
panorama. We did, however, come up with plenty of panhead
and leveling ideas while we were shooting this series of
panoramas. Our compass/bubble level panning device was
one of them.
- 322KB
panorama of Tomorrow Land at the Happiest Place On
Earth
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- For a detailed description on the use of a monopod
with QTVR, ckeck out:
- www.OutsideTheLines.com/qtvrmonopod
Underwater
Panoramas
Equipment Preparation, Handling, and
Use
Camera Equipment
You just got your diver certification, so now you want to
take underwater panoramas. What now? First, you need to get
yourself some underwater photographic equipment. An example
of your basic underwater gear is the following:
- Nikonos V underwater camera body
- Nikonos V 20mm lens (equivalent to a 28mm lens above
water)
- Your favorite underwater strobe
- Bracket to hold the camera and strobe as one unit
with the camera sitting on an L-bracket to increase the
vertical field of view. All bracket hardware should be
made of aluminum with stainless steel fasteners.
Now that you have your basic underwater photo gear, you
need to become one with the equipment. Get used to taking
photos underwater, messing with the strobe, focusing and
setting the lens aperture. Learn how to clean the equipment,
learn how to ready it for underwater use. Once you are
comfortable with the use your equipment, do it some more.
Practice, practice, practice.
Tripod, Leveler, and
Panhead
Now you are ready to put together your underwater
panorama gear: your basic tripod, leveler, and panhead. The
key to picking gear is ease of use. The equipment must be
easy to setup, easy to take your images, and easy to tear
down. Easy is the key word here because you are underwater
and have other, more important things to think about, such
as how much air you have left and making sure your dive
buddy is not getting into trouble.
To start with, you need a good solid tripod - sound like
a familiar theme? For underwater use, this is more important
than ever. You should pick a tripod that is solid and can
take a beating. The best underwater tripod is one that can
be disassembled and put back together without too much
trouble. The Bogen 3001 is a good choice since it is very
easy to set up under water and can be cleaned and serviced
easily. For underwater use, the rubber leg end caps and the
center post end cap should be removed to allow for water
drainage and quick air escape. Once you have your tripod
picked out, you need to pick out a pan head. We chose to use
the standard Bogen 3047 pan/tilt/swivel head for use as our
panhead. The setup is simple and our custom compass markings
are readable while floating above the equipment. We preset
the tilt and swivel portion of the head since below the pan
head we use a Bogen 3115 ball camera level. This leveling
device is ideal under water as there is only one adjustment.
You loosen the ball, level the head, and tighten the leveler
down - a process that takes maybe 30 seconds. The last, but
most important item, is weight. You will need to add some
weight to your tripod setup. Trust us. The weight should be
added at the bottom of the tripod legs and is needed to keep
the entire setup sitting firmly on the ocean floor, rock
steady to keep the influence of the ocean's surge to a
minimum. An explanation of creating your own tripod weights
can be found on the hardware creation page.

Preparing the Equipment
Now that you have your tripod equipment, you need to tear
it all apart. Starting with the tripod itself, tear down as
much of it as you can. You need to remove all the white
lubricating grease you can find. The white grease can not
handle the severity of ocean water so you will need to
replace it with silicon dive grease. You can get jars of
silicon grease at your local dive shop. In addition to the
silicon grease, you should get a can of silicon spray while
you are there. You should apply the silicon grease liberally
to all internal moving parts where you found the white
grease. You should then spray the rest of the tripod with
the silicon spray. Reassemble the tripod and wipe it down
with a cloth to remove most of the excess silicon. You then
repeat the process with the ball leveler. Being careful not
to scratch either the ball or the socket, put plenty of
silicon lube on both the ball and socket. You should then
lube all adjustment bolts and threads and spray the rest of
the unit. Again, wipe off most of the excess silicon. The
next part is a pain, but must be done. You need to
completely break down the panhead. If you are using the
Bogen #3047 pan/tilt/swivel head, you need to remove the
compass marker on the pan section and the swivel marker on
the swivel section to get to the retaining bolts. These
markers are made of plastic and have sticky backs - you may
or may not want to keep them. For our use, we have discarded
them since we use our own removable marker plate for the pan
marker and the swivel marker is simply not useful for
panorama creation. Once you remove all the retaining bolts,
the pan/tilt/swivel head should fall apart in your hands.
Use the silicon grease liberally on all internal parts,
threads, and bushings. Spray the rest of the parts with the
silicon spray. Reassemble the unit, being careful of where
all of the plastic spacers and bushings belong, and verify
you have put it together correctly. Wipe off most of the
excess silicon lubricant with a rag. You should then attach
the ball leveler to the tripod and the panhead assembly to
the ball leveler.
Congratulations, you are now the owner of an underwater
capable tripod unit. After an underwater outing, you should
wash the unit with warm fresh water to remove all salt and
sand contamination, and then make extensive use of the
silicon spray. Use the silicon grease for those parts you
can get to easily such as the ball and socket of the leveler
and all adjustment threads you can get to. A complete tear
down and lube session is required every so often; the
frequency is up to you.
Above Water Dry Run
You should now have two distinct pieces of equipment. The
first piece is the camera/strobe combination and should be
attached to a common bracket. This bracket will be attached
to the second piece of equipment, the tripod/panhead
combination. This second piece of equipment consists of the
tripod with leg weights, a ball leveler and panhead. Before
entering the water, a dry run should be performed.
The camera should be configured with the correct film and
lens aperture setting. The strobe should be set for the
environment you are going to photograph. These camera
settings come from your experience in taking underwater
photos. This case is no different.
Next, the tripod is set up and tested. The ball leveler
is adjusted to be level. The tilt and swivel adjustments on
the panhead are then set so that they are level. The tilt
and swivel adjustments need not ever be changed from this
position, so they should be locked down tightly. The ball
leveler is responsible for leveling the unit and the pan
adjustment is responsible for the panorama. Be sure your
panning compass marker is attached securely to the panhead.
It is no fun to have to guess at 50% image overlap
underwater.
There should be a quickrelease at the bottom of the
camera/flash unit which mates into the panhead on the tripod
unit. For our setup, the panhead uses a large hex
quickrelease mount and is suitable for the weight of the
camera unit. The camera unit should then be clamped to the
panhead to verify all is well with the setup. You should now
be ready to carry out the same procedure underwater.
Setting up underwater
Since both of these groups of equipment are large and
unwieldy, each should be carried into the water by different
divers. The first diver will bring the tripod group down,
open up and tighten the legs, and then level the panhead.
Only the top two leg sections of the tripod should be used
and the legs should be opened wider than normal. You tend to
want the tripod sitting low and squat to avoid being moved
by any current or surge. You want it as immovable as
possible since you only have one chance to get the panorama.
Once the tripod setup is finished, the second diver will
verify that the tripod is set up correctly and then attach
the camera bracket group to the panhead. The first diver
should then verify the camera is setup correctly. All of
this is done while hovering above the ocean floor to avoid
kicking up dirt and sand. The entire experience is what one
might imagine it feeling like to work in outer space,
basically setting up a piece of equipment in a weightless
environment.
Which brings us to our next important point. The
equipment you carry down with you is not buoyant, meaning it
sinks, it is very heavy. To achieve a controlled decent, you
will need to add a lot of air to your BC (buoyancy
compensator). When you place the equipment on the ocean
floor and let go, you will rocket to the surface, causing
yourself an agonizing death. To solve this problem, you need
to let the air out of your BC once you hit the bottom and
are ready to let go of the equipment you are holding. Do not
forget to do this - you have been warned.
Shooting the underwater
panorama
You are now ready to image your panorama. Verify the
aperture settings on the lens and set the focus. Verify that
your strobe is ready to go. Verify that your dive buddy is
out of the camera's view and is going to follow the camera
rather than lead it. You should do this since this makes it
easy to know if you are in the shot or not. It also keeps
the shot free of any kicked up sand and dirt since you are
not following their fins. Do not hold onto the camera rig,
if you do you will inadvertently cause it to move and
require you to start over; be sure to float above it. When
you advance the film or rotate the panhead for the next
shot, do not hold on to the equipment, exert a downward
force to get a sure grip and then make your adjustments.
Once you complete you panorama, go for a swim. Check out
the scenery. Have a nice dive. The entire photo process
should take no more than 10 to 15 minutes. You should have
plenty of air left to cruise around. Don't forget to grab
your equipment on the way back.
222KB
Example of an underwater panorama taken inside Second
Cathedral off of the Hawaiian island of Lanai. The big
problem with this panorama is that we had only taken 12
images where 16 or more were needed. Due to the lack of
image overlap, the panorama has a great deal of banding
because the flash coverage was not great enough to provide
balanced lighting. For underwater panoramas, both the lens
type and flash coverage will determine the amount of image
overlap required.
Image Quality Part
1
As Defined by Download Speed vs. Panorama
Size
- The following example attempts to show the difference
in web download speed versus image quality. The idea is
not earth shaking, but we felt the need to demonstrate
the difference. The idea being that there is a point at
which download time outweighs the importance of image
quality. That is, there is a point at which the panorama
simply takes too long to download and you lose your
audience. There is another point in which the image
quality is simply too poor and you lose your
audience.
- This
first panorama is 33% the size of the original at 144KB.
Note the quality of the image and the loss of detail when
zoomed in.
-
- This
second image is full size at 945KB. Note that in this
case the image takes far too long to download, but that
the quality is sufficient enough to see the detail of the
image.
-
- This
third panorama is 66% the size of the original at 463K.
It has sufficient image quality and an acceptable
download time compared to the full size
panorama.
Image quality Part
2
As Defined by Download Speed vs. Compression
Settings
- The following examples show the effects compression
on image quality. The parameter for using the p2mv tool
to set the image quality compression settings is the
following:
- Image quality of movie (default=1023
(codecMaxQuality))
- -quality <image quality>
-
- Using the Cinepak compressor, we can adjust the image
compression to reduce the image size but at a cost of
image quality. By adjusting this setting, as well as the
actual pixel size of the panorama (as demonstrated
above), you can maximize your panorama acceptability of
quality and download speed for web delivery.
- This
first example is a 414KB panorama with a maximum quality
setting for the Cinepak compressor.
-
- This
second example is a 131KB panorama created with a quality
setting of zero (-quality 0).
Number of
Images
Depends on Lens and Lighting
The following image examples show the differences in
image quality relating to dark bands produced by extremes in
exposure value from one image to the next. Note that as the
number of exposures is increased, the banding effect is
reduced due to smoother image blending from one to the next.
If the camera exposure setting of the entire panorama were
consistent or the scene itself had balanced lighting
throughout, the banding effect would be reduced. Your images
would not require as much overlap, thus reducing the number
of images required for your panorama. By increasing the
amount of overlap, you can get away with fully automatic
camera exposures without significantly increasing the
banding effect on the panorama for unbalanced scenes such as
the following. We have several wide angle examples from a
Canon PowerShot 600 digital camera of image overlap in the
case where there is a large exposure difference between
frames due to shooting into the sun. We have provided both
blended and non blended stitched images to show how the
blend command in the stitcher can be used to average out the
exposure differences.
- 70%
overlap - 24 images for full panorama
- 55%
overlap - 16 images for full panorama
- 40%
overlap - 12 images for full panorama
- 30%
overlap - 10 images for full panorama
- 10%
overlap - 8 images for full panorama
Subjective vs.
Objective Part 1
Finding the Forest Among the Trees
- The following is a quick comparison between an image
with too much detail "noise" versus the same panorama
which has gone through some Photoshop "enhancements". The
left hand panorama has a lot of detail, but much of it is
just noise; you can't really get a grasp of what the
panorama is trying to convey. In the right hand panorama,
you get a better idea of the environment you are in
although there is much less detail. This is a case of
basic information overload which has been attenuated by
removing much if the small detail, leaving only the
important information for the viewer.
- Two
234KB panoramas of Disneyland's ToonTown
Subjective vs.
Objective Part 2
Panorama with Different Paint
Techniques
- As we have seen with the above panorama, you can
enrich a panorama by reinterpreting the panoramic scene
using various post processing techniques. In our case, we
simply ran the stitched panorama image through a
Photoshop filter to reduce the amount of irrelevant
detail into something a bit more subjective. In addition
to reducing panorama detail, one can also add to the
visual richness by other photographic tricks. While your
original image may be interesting and true to life, you
can spice up your panoramas with a bit of surrealism
using this technique. You could reduce the color
saturation and adjust the colors for a pastel 50's look,
or you could turn your panorama into a duo tone to give
the viewer a sense of calm and serenity. The following
example is a panorama which has been changed to a
contrast enhanced duotone image.
- 635KB
panorama of Emigrant Wilderness overlooking Relief
Reservoir
- In addition to changing the look of the panorama for
artistic reinterpretation, you can also use this
technique to mask a camera's poor image quality. The
following panorama was taken with a Canon RC-250 video
still camera which produces 250 lines of analog video and
is of extremely poor quality. The left hand image shows
an untouched panorama from this camera. The right hand
image is an altered panorama which attempts to give the
feel of looking at a panoramic painting.
- Two
246KB panoramas of an outside scene
Circle in
Panorama
De-warp Correctness Test
- To help tune the warp/de-warp parameters of both the
stitcher and msnm tools, you can use this little trick.
Create a panorama that contains a large circular object
that is relatively level with the camera. This can be a
large truck tire or wheel, or a round business placard.
The idea is to create your panorama with the tool
settings you have found to work and tune them by making
sure the circular image in the panorama is a true circle.
If the stitchers 'fovy' parameter or the msnm vPanRange
parameter are sub optimal, you will see an oval rather
than a true circular image of your control object.
Another method is to take images with 20% overlap, and
paint a circle onto the center 20% of one of your images.
This leaves 20% on either side of the painted circle for
image blending and offset errors when the panorama is
stitched. Due to the relatively small size of the painted
circle, in addition to its location in the center of the
image, it should be close to what one might photograph if
the object actually existed.
- Individual
frame with circle painted over center 20% of
image
- After you have stitched and created a panorama, you
should see the painted circle you have added. If all of
your parameters are correct, you should have a circle
rather than an oval.
- 91KB
Panorama built correctly with painted circle
Adding A Signature
Line
- A signature line is a copyright notice, a personal
signature, or other important information you may want to
attach to your panoramas. In our case, we will detail how
we added the following signature to an example
panorama:
- ©Concepts In Motion -
www.OutsideTheLines.com
-
First, we will share with you some of our original
ideas on this and why we decided against them. The
easiest way to add a signature is to paste the text into
the panorama image somewhere at the bottom of the frame.
The resulting signature, when viewed in the panorama
movie, is curved, unreadable, and generally
unprofessional looking. It does seem to be in a good
location otherwise.
- Example
of curved text
-
So you figure that the problem is that the text is not
curved, so you think about orienting the text vertically.
This is not curved, is readable (though sideways), but
looks silly and unprofessional.
- Example
of vertical text
-
So you try the text oriented vertically but with the
text rotated. A bit better, but still does not look any
better than previous tries.
- Example
of vertical rotated text
-
The only solutions are either not having a signature,
or bending the text so that it matches the warped image.
We went with the latter technique, dealing with the few
issues of warping the text to match the panorama image
itself. The amount of warp is dependent on the
camera/lens combination you are using. The wider the
lens, the more warped the text needs to be to match the
panorama image. The other issue is placement of the
signature text. If the text is to be placed at the bottom
of the frame, the text must be warped upward. If the text
is to be placed in the center of the frame, then no
warping should be required. For the top of the frame, the
text must be warped downward to match the panorama
image.
- To resolve these problems, one simply needs to take a
partial panorama of an object which will act as a
template for the warped text. For example, find a park
bench with a horizontal rail upon which you could imagine
your signature line placed, similar to where an
advertisement might be located. Take a partial panorama,
3 or 4 images, so that you capture the entire template
object - the park bench in this case. Make sure the
template object is located at the bottom of the panorama,
in about the location you want your signature line to
sit. Once you create your partial panorama image, you
should extract from it just the warped template image
upon which you will create your signature. As an example
of this, we used the back of a kitchen counter as our
template as shown here:
- Extracted
template from stitched partial panorama
-
Once you have extracted your template image, you need
to import it into a drawing application that allows you
to create text along a curved path. In our case, we
imported the template image into Adobe Illustrator. From
there, we created a text path whose curve and width
matched the curve and width of the template.
- We then added our signature text along the path in a
font and size that allowed the text to span the entire
width of our template. After deleting the template image,
we saved the file as our signature text.
- Screen
shot of Illustrator canvas with signature text along
template path
-
From the signature text we create our signature image
as follows. Open the Illustrator file from within
Photoshop at the default size suggested in the open
dialog - the background for this image should be empty,
not filled with any color. We now have some minor
preparatory work to complete before we are able to paste
this image into our real panorama. First, the canvas (not
the image) should be enlarged a bit to give some working
room. Next, to bring out the signature within the
panorama itself, we created a second layer upon which we
airbrushed a light background for the signature text and
set this layer to 50% opacity in the layers palette. Once
we are happy with the look of the airbrushed background,
we merge down layer 2 (the light background) into layer 1
(the text) and save it as our completed signature image.
You should merge down layer 2, rather than flatten the
image, to preserve the transparent background of your
signature image.
- Screen
shot of Photoshop canvas with painted background and
text
-
At this point, we simply open a panorama image created
with the same camera and lens combination as that used
for our signature image, rotate the image 90 degrees
clockwise, paste the signature image at the bottom of the
panorama is some appropriate place, rotate the panorama
back 90 degrees counter clockwise, flatten the image, and
save the finished panorama as a PICT file. You have now
created a professional looking signature line, which when
viewed from the panorama movie, will be flat and readable
along the bottom of the frame. Be aware that if you
intend to reduce the size of your signed panorama image,
the signature will become blurred and unreadable. To
prevent this, you should recreate your signature image by
opening the Illustrator signature text at the reduced
percentage you intend on reducing your final panorama
image. For example, if you intend to reduce your panorama
image by 50% for the final panorama movie, you should
first open the signature text at 50% size, create its
painted background and paste that entire thing into the
50% reduced panorama image.
- Example
of unreadable text as a result of reducing the final
stitched panorama image size after the signature text has
been added
-
- Example
of readable text as a result of reducing the final
stitched panorama image and signature text
separately
-
- Example
of correct signature text
-
- 946KB
panorama with the final signature added
Project Run Through -
Bear Harbor at Sinkyone Park
Sinkyone Wilderness - Bear Harbor
Camp
The Bear Harbor QTVR project is an example of why digital
cameras with removable storage make a lot of sense. Bear
Harbor is a camp located along the California pacific north
coast in the Sinkyone Wilderness. We were there for 4 days
of basic rest and relaxation, and on the second day we
realized we were having warm sunny days with blue skies - a
minor miracle for the north coast. With this revelation, we
decided to pull out the Canon XapShot video still camera and
take a bunch of panoramas. We had enough floppy disk storage
and battery power for 40 nodes. We mapped out the camp, the
beach, the bluff, and up and down the coast on a Nut'n
PAD writing tablet and divided up the different areas
with the number of nodes we thought would be appropriate. We
started shooting around 11:30 in the morning, shooting from
one end of the camp to the beach. We shot the bluff, then
shot up and down the coast. Each node took around 90 seconds
to set up the tripod, level the head, and take the shots for
the panorama. The camera has auto-exposure only metering so
we did not have to do anything special here, just point and
shoot. We then walked, with camera on the tripod, to the
next location. All in all, the complete set of panoramas
took a few hours to complete, all in one early afternoon. If
the images did not turn out, or if some of the panoramas did
not work because we were not very careful about tripod
levelness, or whatever, we were only out our time and not a
bunch of expensive film and processing costs. We had time,
that is why we were there, to enjoy ourselves, and our
panorama shooting afternoon was fun, it didn't really matter
if the the shots worked or not. As it turns out, the shots
did work, quite nicely in fact, even with the ultra poor
quality Canon XapShot camera. The image quality is not very
good, but gives you the idea of the surrounding area, so
much so that you may want to visit the the place. We would
not have done this if there was any expense involved. We did
this because we were there, had the benefit of good weather,
and had a camera with removable storage and lots of reusable
media.
3.4MB
multinode panorama of Bear Harbor at Sinkyone Park. The
Bear Harbor panabout was built using half sized stitched
images. The original stitched image size was 2496x320 and
produced a 9.2MB multinode panorama. With each stitch
reduced to 1248x160, the file size has been reduced to 3.4MB
without losing too much in image quality.
Once back at home with 13 floppy disks worth of images, 3
complete panoramas per disk, it was time to do the actual
work. We used a PowerMac 8500 to record in millions of
colors at 320x240 the NTSC images from the video out port of
the XapShot camera. Image folders corresponding to the
floppy disks were created and numbered according to the disk
number itself. All images were saved into their respective
folder, each folder containing the images needed for 3
panoramas. The following is the folder hierarchy for the
Bear Harbor multi-node QTVR project. The thing to take note
of is the naming scheme used for the files. In order for the
Scene Editor to work correctly, all node names are required
to have indexes of increasing magnitude. For this reason, we
split the node sections into different numerical ranges. For
example, the Beach section contains all the 100 series
nodes, and the Bluff section contains all the 400 series
nodes.
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