VR panorama workflow with Hugin, GIMP and SLANT pano head

This is a set of scripts intended to build 360° x 180° panoramas shot in single-row technique with a SLANT panoramic head.

The intention is to transform a set of photos into a equirectangular panorama with as little user intervention as possible.

Components

This repository is split into two parts:

A script that uses the Hugin CLI tools to create a Hugin project file
A GIMP plugin to automate the pre- and post-processing required for patching the zenith and nadir

Requirements

bash and python3
The Hugin suite. The script should work with any recent version. It was tested with Hugin 2023.
GIMP. The plugin requires a GIMP version with Python3 interface; at the time of writing this means installing the 2.99.x development version, that beta version is required until GIMP 3 is released.

The beta version can be easily installed via flatpak:
```
flatpak install --user https://flathub.org/beta-repo/appstream/org.gimp.GIMP.flatpakref
```
- The GIMP step (zenith and nadir patching) is already possible with GIMP out of the box (see Filters -> Map -> Panorama Projection); the plugin only eliminates manual steps through automation.
- To make GIMP aware of the plug-in, point it at the "gimp-plugin" folder in this repository:
  - Edit -> Preferences -> Folders -> Plug-ins
  - Add the path to the "gimp-plugin" directory
  - After restart, there should be a new menu entry (Filters -> Panorama)

Usage

Create panorama

Call create-pano.sh, pointing it at the first photo of the series. It will select 8 consecutive image files for the panorama.

e.g. scripts/create-pano.sh /path/to/img/DSCF0025.JPG
The script creates a Hugin project containing the photo set, pre-aligns the photos (using known parameters like slant angle, lens properties, angle between images), creates control points and conducts a first optimization run.
After the Hugin project is built it is opened in Hugin Panorama Creator GUI.
Hugin GUI should already show a decent panorama; now it's possible to do some fine tuning (move/drag/straighten, further optimization etc)
Select panorama format & resolution
Finally stitch the panorama from the GUI or on the command line (e.g. hugin_executor --stitching tmp/pano_final.pto).

Patch zenith & nadir

Open the stiched panorama in GIMP.
Run Filters -> Panorama -> Extract Zenith and Nadir
- Two new layers should appear, containing the Zenith and Nadir in rectilinear projection.
Patch the Zenith and Nadir layers until satisfied.
Run Filters -> Panorama -> Reinsert Zenith and Nadir
- The Zenith and Nadir layers should be reverted into equirectangular projection.
The panorama can now be flattened & exported for further editing or publishing.

Compatibility

The Hugin script was created for and tested with a Samyang 8mm f/2.8 Fisheye & Fuji X-E2 on a PT4Pano SLANT pano head. This setup requires 8 single-row shots for a 360° x 180° panorama.

The script should work out of the box with any single-row fisheye setup using 8 shots for 360˚.

It should be easily adaptable for similar setups that use a different number of shots.

TODO

Support exposure bracketing for HDR panoramas.
Use ML / GAN to "auto-patch" zenith and nadir without user intervention.

patrislav1/pano-workflow