Acquiring full sphere images:
Two opposing fisheye images with 180° or larger fields of view
are required. One approach is the Spherecam,
a camera system that uses a pair of 220° Nikon fisheye lenses on a
pair of Nikon F camera bodies.
An alternate approach is to take a pair of opposing photographs
180° fisheye lenses. Suitable lenses include the Nikon 8 mm f2.8
and some of the Sigma 8 mm f4 lenses. Not all of the Sigma 8 mm
have the necessary 180° coverage.
Processing full sphere images
Once fisheye photo pairs have been photographed, they need to be
combined in a computer. For the examples here, the combination is
with Adobe Photoshop, version 4.0. The first step is to form a
perspective intermediate image. From this image, the following
The following section describes how to form the cylindrical
image and then form a VR compatible view (option 1) that can be
with the RealVR viewer. The
for options 2 and 3 are described in another article. Much of
processing can be automated as an Action in Adobe Photoshop.
here to download an action file for processing Spherecam
This action file would need to be slightly modified for processing
degree fisheye images.
VR compatible view in all directions -- similar to Apple QTVR
Cylindrical format panoramic image -- similar to the image
a scanning panoramic camera.
Spherical format hyperfisheye image -- similar to the image
a 360° fisheye lens.
The following list are the Spherecam processing steps needed to
the cylindrical intermediate image:
Scan film frames -- For the Nikon LS-1000 film scanner
size 23 x 23 mm at 1350 or 2700 dpi. This minimizes unneeded
interppolation steps. Center the scan area on to the circular
Scan both images.
Rotate both images to the same orientation -- Use
Canvas>) options in Photoshop as needed to bring both images
into the same
Start Photoshop action sequence -- The following sequence
can be automated as a macro in Photoshop version 4. The action
that the imagess were scanned at a 23 x 23 mm size at 1350 dpi.
Convert image 1 to rectangular form -- Use the polar to
conversion filter (Filter>Distort>Polar Coordinates) to
convert the 1st
imagee to a cylindrical projection. Use the Polar to Rectangular
in this filter.
Increase the canvas size of image 1 -- Increase the
from 0.908" to 1.481" when using a 220° fisheye lens (ratio of
Select image 2 and convert to rectangular form -- Use the
to rectangular conversion filter to convert the 2nd
a cylindrical projection.
Rotate image 2 by 180 degrees -- This will align the
lower and upper
Copy image 2 to the clipboard -- The entire image should
Close image 2 -- This image is no longer needed.
Paste image 2 as a layer onto image 1 -- A new layer is
Align layer 2 relative to layer 1 -- Image 2 is aligned
to image 1 by using the offset filter
(Filter>Other>Offset). Typical offsets
are around 4450 pixels vertical and 0 pixels horizontal. The
must be set to the wrap around mode.
Blend transition between layer 1 and 2 -- Create a layer
blend between the images.
Apply color corrections to both layers -- Apply any
corrections, both to make the transition region disappear and to
the scene color balance andd gamma, etc.
Merge the layers into a single image -- When the layer
is complete, merge the 2 layers into a single layer.
At this point you have the cylindrical perspective intermediate
image. Use the following additional processing to form a
Save the intermediate file as a JPG -- Convert the image
desired pixel density and size and save as a jpeg file.
Create a VRML control file -- The VRML control file can
in Wordpad or another text editor. The JPG image file name needs
imbedded in thee VRML file. The VRML control file should end
with the file
extension name ".ivr". The following is an example of the text
in the ivr
file assuming that the jpeg image name is "example.jpg".
#VRML V2.0 utf8
Click Here for an example.
Install the RealVR viewer -- The RealVR viewer extracts
views from the JPG image by using the ivr file to define the
There are several types of RealVR viewers including stand alone,
plug in and Internet Explorer plug in. These viewers can be
at no cost from http://www.livepicture.com
. You can test the viewer by double clicking on the ivr file
that you created
and associating it with the internet browser or stand alone
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© Copyright 1996, by Dan Slater, All Rights