alignment_procedure crashes when both eyes are in the same position

[Dobiasd]

When looking at a face from the side, the landmark detector may give the same position for both eyes.

In that case, retinaface.commons.postprocess.alignment_procedure crashes with UnboundLocalError: cannot access local variable 'angle' where it is not associated with a value.

Some IDEs also highlight this problem:

Here is a minimal example to reproduce the problem:

import numpy as np
from retinaface.commons import postprocess

postprocess.alignment_procedure(np.zeros([123, 123, 3], dtype=np.uint8), (10, 10), (10, 10), (33, 33))

[Dobiasd]

Of course, it would be nice if pylint would catch such problems already in the CI.

I've opened a StackOverflow question asking if enabling such a check is possible.

[serengil]

Good spot! Do you mind to share your input image? Would be easier to fix if i can reproduce.

[Dobiasd]

It happened while processing a video stream. I no longer have the problematic frame, but I'll try to reproduce one by moving in front of my webcam. 🕺

[Dobiasd]

I've tried, but so far failed to align my head in a pose to fulfill the required condition.

Hope you can maybe fix it even without such an example image.

[serengil]

No problem, we can still fix it.

[serengil]

@Dobiasd if we set an initial 0 value to angle in alignment produce function, then this will be sorted.

Do you mind to create a PR for this? I would like to see your name as a contributor because you found this issue.

https://github.com/serengil/retinaface/blob/master/retinaface/commons/postprocess.py#L33

[Dobiasd]

FYI:

While pylint is not able to catch such bugs in the linter step, mypy (with --enable-error-code possibly-undefined) is. 🎉

So in case you're interested in preventing such issues automatically in the future, using mypy could be an option. 🙂

[serengil]

Oh no, very satisfied with pylint, do not want to switch anything else :)

[Dobiasd]

Ah, no, I did not mean to replace pylint with mypy, but adding mypy to the CI. mypy is a type checker and solves different problems than pylint (a linter) does. Not only our team at work, but also me in my private projects (example) use both in conjunction, and I like this combination a lot. 🙂