Panoramic & HDR Imaging (June 2004)

Using my trusty Canon PowerShot G3, I've been making some spherical panoramas. Because I don't have a particularly wide angle lens (it's equivilent is about 38mm-40mm lens on a 35mm film camera), these require approximately 46 photos for one spherical exposure.

The tripod mount is crude because I am planning to build something better when I aquire a new camera. The reason for the structure is to keep the camera's magic entrance pupil centered as it is tilted and panned. Without it, the photos would not stitch properly because the image would shift from frame to frame. The images are stitched together using RealViz Stitcher. A benefit of using this system is that the images can be output at a very high resolution. The three images below are links to Quicktime VRs. They are all single exposure value panoramas which may be explored.


Apartment 2.79MB

Apartment Building Deck 886KB

Denver, Colorado 1.05MB

or high resolution
Denver, Colorado 14.86MB

Single exposure value panoramas are nice for exploring an existing location, but some interesting lighting information may be gathered when one increases the dynamic range of the capturing process. Consumer digital cameras, especially, have a low dynamic range... Human vision is by far more flexible. In this next image, I took 276 photographs to create the sphere (6 exposures from 1/2000s to 1.6s for each of the 46 photo locations). The result is tone mapped so that it can be viewed on a conventional computer display. The real benefit of this is being able to gather lighting information about the scene. This lighting information may be used in some 3D software packages for lighting a scene.

Image based lighting can be done with a single exposure panorama. Some of the lighting information that was available in the panorama is seen in the picture below left. However, with HDR panoramas more of the lighting information may be extracted. We can actually define a sun in the HDR panorama because it was one of the few bright spots in the fast exposures. In the example, below right, the dummy has bright highlights corresponding to the location of the sun in the HDR. The reason there are no shadows on the ground is that the dummy object is actually floating in space. The background photo is the spherical panorama which is lighting the scene.


You may download the HDR 2.0MB, and use in your own projects if you wish. High Resolution HDR available by request.

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