Nonlinear Stitching I have made a small VBA Excel Program for the Merlin Orion Panogear to optimize 360 x 180 degrees panoramas for sky and bottom.
The sky and bottom is not linear for the grid calculation. The Excel Program uses your camera specification to optimize de grid.
The Excel program exports preset files and papywizard like xml code for the grid importation. The nonlinear stitching gives better results for the sky and the bottom. It is not necessary to take pictures from the Merlin Orion gear on the bottom. The Excel VBA program was also developed for my own gear. I have developed it in my technician school. We have 2 prototypes and are looking to commercialize the product.
I use a lot the Merlin Orion panogear from kolor.com. I use an external 12V plumb accumulator. But the grid stitching was not enough precise. And the speed of the Merlin panogear for gigapixel panoramas was too low.
The VBA program can also be used for smaller panoramas.