B-splines

What an interesting thing this is.

With it you can resize this:

To this:

Without looking like this:

While used to describe continuous surfaces in 3D models, their ability to produce a value at sub pixel resolutions con be abused here to unfold the 360° panorama more smoothly.

Panorama when unfolding with the nearest pixel to the calculated value:

Panorama when unfolding with the sub pixel value:

The down side is that using brute force to calculate every pixel amounts to couple of hours per full resolution image.

Next step, use science & math to speed things up!

And to finally fix the aspect ration (now that the images are smooth).