Sunday, January 21, 2007

Stitching Your Panorama

There are many good panorama stitching programs to choose from; I like PTGui with Panotools because it give me maximum control over the final output. The basic process is:
  1. Load your images into your stitching program with the first image containing the "normalized" orientation for the panorama. By normalized I mean straight and level, since all other images will be oriented with respect to this one. I usually include my nadir shot for control point calculations, but omit it before the final stitch.
  2. Generate your control points and/or manually add your own pairs.
  3. Examine the control point table and remove errant points until the overall error is less than two pixels. Redefine control point pairs if necessary.
  4. Stitch to an equirectangular .tif file
  5. Rotate the nadir by applying -90° pitch and stitch with these settings to a nadir file.
  6. Use an image editing program to fill-in the nadir circle. Sometimes I use a handheld nadir shot and stitch it during step 5. Save the nadir file.
  7. Load the nadir file into PTGui and reverse the pitch, returning the panorama to its original orientation. Save the file to a temporary file.
  8. Using your image editing software, combine the original stitch without nadir data with the temporary file your just saved. Blend the nadir into the original and save the result as a complete spherical equirectangular image.
  9. Use Pano2QTVR or other similar programs to create Quicktime VR movies.