Panorama and QTVR Notes

Uses:

Making Panos

Basic Steps and tips:

Use the following table to help determin number of images to take. I reality, you will probably be able to get away with the 16 shots our tripods are set up for.

Focal Length FOV Horiz. FOV Vert. Pan Steps
15mm 110° 72° 10
18mm 100° 66° 12
20mm 94° 62° 12
24mm 84° 55° 16
28mm 74° 49° 16
35mm 62° 41° 18
50mm 46° 30° 24


More Tips:

For the Olympus cameras set the camera on SQ/VGA/High which is SQ(640x480) for resolution and High Quality for compression. This should allow you approximately 32 images on the card. If you are using another camera, use similar settings if possible.

If using a (very)pro camera, try using a rectilinear flat field lens to minimize the distortion.

Nodal point:

Optical center of the lens where the rays of light converge and the image flips. If the optical center ois offset from the center of rotation, objects in the foreground look as if they are sliding in relation to the background. In most landscapes, objects are far enough away so it won't matter.

Most heads have protractors to help maintain consistent frame overlap.

 

The number of images depends on the focal length, lighting conditions, and your final image requirements. When the lighting differences in a scene are distinct, allow more frame overlap to avoid banding. Image overlap should be no less than 20% and no more than 50%. Too many frames is better than too few. Shoot an even number of frames.

 

 

Consult the QTVR Authoring Studio Manual for instructions on stitching the panos.

Stitching the panos:

1. Download and organize

2. Resize, rotate, and sharpen (if necessary)

3. Retouch

4. Stitch.

Optional: retouch and composite. Stitch again

Optional: add hotspots.

5. Display or print.

Image recognition algorithms automatically control the overlap of images. Most stitching software also smooths out uneveness of the light to eliminate banding. When you enter the focal lenghth of the lens used to capture the images, the software builds the correct curvature into the finished movie.

It is often helpful to downsize your images before you stitch them.

If 640x480 don't downsize. If your making large prints, don't downsize.

Size down in increments of 50%, throws out every other pixel, faster and less anti-aliasing.

Do not crop individual source images, all images must be same dimensions.

Use unsharp mask judiciously, QTVR Studio allows you to control sharpening. Perhaps use after sizing an image down.

Retouch:

During the stitching process, you have 2 chances to retouch the image before you stitch the individual source images together and after the initial stitch.

The first retouch includes the following:

1. Basic color and tonal correction.

2. Remove Artifacts

The second retouch takes place after the initial stitch:

1. Finessing color and contrast.

2. Remove stitching artifacts

3. Composting exposures or creative backgrounds.

www.vrview.com

Stitch:

1. Load source images

2. Determine camera settings

3. Build a preview stitch

4. Adjust stitch alignment

5. Build final panorama

Optional: Save the file for printing (pict or jpeg). Retouch and/or composite. Print.

6. Create the file for interactive viewing.

Optiional: Embed into Web page.

7. Add hotspots.

Horizontal pixel dimension limitation of the pict file format is 4095 pixels.

Rotate by 90 degrees.

Compression:

1. Cinepak: offers fast decompression for playback, but compression in production is slow. Can add artifacts.

2. Sorenson

3. JPEG good for photographic based panorama images.

4. Graphics: 3d artists, graphic designers, and industrial designers who create immersive images.

Tiling:

only the part of the image actually on the screen is decompressed and loaded into ram. Tiles to the left and right are partially decompressed. Images are rotated 90 degrees and then tiled into 24 even tiles. On playback, they are rotated back and placed edge to edge for a seamless image.

Notes:

2 Groups of Immersive Images: Panoramic and Object

A pano that does not extend completely around is called a partial.

Multi-row object movies show top and bottom surfaces as well.

Both kinds of images can have hotspots which can go to another immersive image, a higher resolution image, a sound, a text, or any other kind of file.