Replace FFT with a Nearest Neighbor Ransac approach and refactor SkyFit

[Cybis320]

Replace deprecated imreg_dft with scikit-image.

[markmac99]

I'll have to assume the maths is correct as its not an area i'm familiar with. I left a couple of comments in the review.

[Cybis320]

Ok, I think it works. It's slightly more accurate (although this a coarse tool so it doesn't matter) and it's slightly faster.

[dvida]

Would could also just use RANSAC to reduce complexity: https://scikit-image.org/docs/0.25.x/auto_examples/transform/plot_matching.html
Apparently there are also USAC and MAGSAC that's included in opencv (>v4.0) which are apparently better, but I never used them myself.

[Cybis320]

Would could also just use RANSAC to reduce complexity: https://scikit-image.org/docs/0.25.x/auto_examples/transform/plot_matching.html Apparently there are also USAC and MAGSAC that's included in opencv (>v4.0) which are apparently better, but I never used them myself.

Great suggestion!! It's so much better. 185x faster, perfectly accurate, and 180 less lines of code.

[markmac99]

@Cybis320 I commented this on the latest commit, but ImageIO version 2.33 isn't available for Python 3.7 which is the standard on Buster builds. The last version thats compatible with python 3.7 is 2.31.2. See https://pypi.org/project/ImageIO/#history for more.

  Could not find a version that satisfies the requirement imageio>=2.33 (from -r requirements.txt (line 16)) (from versions: 1.1-linux32, 1.1-linux64, 1.1-osx64, 1.1-win32, 1.1-win64, 1.2-linux32, 1.2-linux64, 1.2-osx64, 1.2-win32, 1.2-win64, 1.3-linux32, 1.3-linux64, 1.3-osx64, 1.3-win32, 1.3-win64, 0.2.1, 0.2.2, 0.2.3, 0.3.0, 0.3.1, 0.3.2, 0.4, 0.4.1, 0.5, 0.5.1, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.1.2, 2.2.0, 2.3.0, 2.4.0, 2.4.1, 2.5.0, 2.6.0, 2.6.1, 2.8.0, 2.9.0, 2.10.1, 2.10.2, 2.10.3, 2.10.4, 2.10.5, 2.11.0, 2.11.1, 2.12.0, 2.13.0, 2.13.1, 2.13.2, 2.13.3, 2.13.4, 2.13.5, 2.14.0, 2.14.1, 2.15.0, 2.16.0, 2.16.1, 2.16.2, 2.17.0, 2.18.0, 2.19.0, 2.19.1, 2.19.2, 2.19.3, 2.19.5, 2.20.0, 2.21.0, 2.21.1, 2.21.2, 2.21.3, 2.22.0, 2.22.1, 2.22.2, 2.22.3, 2.22.4, 2.23.0, 2.24.0, 2.25.0, 2.25.1, 2.26.0, 2.26.1, 2.27.0, 2.28.0, 2.28.1, 2.29.0, 2.30.0, 2.31.0, 2.31.1, 2.31.2)
No matching distribution found for imageio>=2.33 (from -r requirements.txt (line 16))
(testsk) pi@uk001l:~/source/testing/testsk $ python -V
Python 3.7.3
(testsk) pi@uk001l:~/source/testing/testsk $ cat /etc/os-release
PRETTY_NAME="Raspbian GNU/Linux 10 (buster)"

[markmac99]

Latest update resolves the imageio issue, however frustratingly we have a new problem on Python 3.7 - the latest build of bcrypt is only available as a tar.gz file, and to build it requires Rust which is not installed / available for Buster 32bit.

Building wheels for collected packages: bcrypt
  Building wheel for bcrypt (pyproject.toml) ... error
  error: subprocess-exited-with-error
 This package requires Rust >=1.64.0.

To work around that i think we need to install the last-good wheel version on python 3.7

bcrypt==3.2.0 ; python_version <='3.7'
bcrypt ; python_version >='3.8' 

in the requirements. Sigh.

[Cybis320]

Isn't that a paramiko dependency? We didn't touch that here or in prerelease. Are you running into issues with a new install on Buster?

[markmac99]

Quite possibly. I was testing by trying to install the requirements on Buster in a brand new virtualenv, so that i can identify any potential incompatabilities. Existing stations might be ok, as they'd have bcrypt 3.2.0 installed already. So, it should only be a problem if someone has a buster-based system and has to rebuild it to buster. Maybe we just make a note in the README file explaining the potential issue.